更新日志
********


Python 下一版
=============

*发布日期: XXXX-XX-XX*


核心与内置
----------

* bpo-38379: When cyclic garbage collection (gc) runs finalizers
  that resurrect unreachable objects, the current gc run ends, without
  collecting any cyclic trash.  However, the statistics reported by
  "collect()" and "get_stats()" claimed that all cyclic trash found
  was collected, and that the resurrected objects were collected.
  Changed the stats to report that none were collected.


库
--

* bpo-38449: Revert GH-15522, which introduces a regression in
  "mimetypes.guess_type()" due to improper handling of filenames as
  urls.

* bpo-38431: Fix "__repr__" method for "dataclasses.InitVar" to
  support typing objects, patch by Samuel Colvin.

* bpo-38109: Add missing "stat.S_IFDOOR", "stat.S_IFPORT",
  "stat.S_IFWHT", "stat.S_ISDOOR()", "stat.S_ISPORT()", and
  "stat.S_ISWHT()" values to the Python implementation of "stat".

* bpo-38405: Nested subclasses of "typing.NamedTuple" are now
  pickleable.

* bpo-38332: Prevent "KeyError" thrown by "_encoded_words.decode()"
  when given an encoded-word with invalid content-type encoding from
  propagating all the way to "email.message.get()".

* bpo-38341: Add "smtplib.SMTPNotSupportedError" to the "smtplib"
  exported names.

* bpo-13153: OS native encoding is now used for converting between
  Python strings and Tcl objects.  This allows to display, copy and
  paste to clipboard emoji and other non-BMP characters.  Converting
  strings from Tcl to Python and back now never fails (except
  MemoryError).


文档
----

* bpo-38294: Add list of no-longer-escaped chars to re.escape
  documentation


测试
----

* bpo-37531: On timeout, regrtest no longer attempts to call
  "popen.communicate()" again: it can hang until all child processes
  using stdout and stderr pipes completes. Kill the worker process and
  ignores its output. Change also the faulthandler timeout of the main
  process from 1 minute to 5 minutes, for Python slowest buildbots.


Windows
-------

* bpo-38344: Fix error message in activate.bat

* bpo-38359: Ensures "pyw.exe" launcher reads correct registry key.

* bpo-38355: Fixes "ntpath.realpath" failing on "sys.executable".


IDLE
----

* bpo-36698: IDLE no longer fails when write non-encodable
  characters to stderr.  It now escapes them with a backslash, as the
  regular Python interpreter. Added the "errors" field to the standard
  streams.


工具/示例
---------

* bpo-38118: Update Valgrind suppression file to ignore a false
  alarm in "PyUnicode_Decode()" when using GCC builtin strcmp().

* bpo-38347: pathfix.py: Assume all files that end on '.py' are
  Python scripts when working recursively.


C API
-----

* bpo-38395: Fix a crash in "weakref.proxy" objects due to incorrect
  lifetime management when calling some associated methods that may
  delete the last reference to object being referenced by the proxy.
  Patch by Pablo Galindo.


Python 3.8.0 release candidate 1
================================

*Release date: 2019-10-01*


安全
----

* bpo-38243: 在将文档页渲染为 HTML 时会对
  "xmlrpc.server.DocXMLRPCServer" 的服务器标题进行转义。 （由 Dong-hee
  Na 在 bpo-38243 中贡献。）

* bpo-38174: 将厂商化的 expat 库版本更新至 2.2.8，这解决了
  CVE-2019-15903。

* bpo-37764: 修复了 email._header_value_parser.get_unstructured 在邮
  件 头不包含末尾空格，以及在其包含无效的已编码字等特定情况下进入无限
  循环 的问题。 由 Ashwin Ramaswami 贡献补丁。


核心与内置
----------

* bpo-38006: Fix a bug due to the interaction of weakrefs and the
  cyclic garbage collector. We must clear any weakrefs in garbage in
  order to prevent their callbacks from executing and causing a crash.

* bpo-38317: Fix warnings options priority: "PyConfig.warnoptions"
  has the highest priority, as stated in the **PEP 587**.

* bpo-36871: 改进了 mock 的 assert_has_calls 和 assert_has_awaits 方
  法 的错误处理。 修复了一个漏洞，它会在将预期的调用绑定到 mock 的规格
  时 静默接收所遇到的任何错误，从而产生误导性的错误输出。

* bpo-38236: Python now dumps path configuration if it fails to
  import the Python codecs of the filesystem and stdio encodings.

* bpo-38013: Allow to call "async_generator_athrow().throw(...)"
  even for non-started async generator helper. It fixes annoying
  warning at the end of "asyncio.run()" call.

* bpo-38124: Fix an off-by-one error in PyState_AddModule that could
  cause out-of-bounds memory access.

* bpo-38005: 修复InterpreterID 和 ChannelID的创建和对比.

* bpo-37994: Fixed silencing arbitrary errors if an attribute lookup
  fails in several sites. Only AttributeError should be silenced.

* bpo-37990: Fix elapsed time in gc stats was not printed correctly.
  This bug was a regression in 3.8b4.

* bpo-37966: The implementation of "is_normalized()" has been
  greatly sped up on strings that aren't normalized, by implementing
  the full normalization-quick-check algorithm from the Unicode
  standard.

* bpo-20490: Improve import error message for partially initialized
  module on circular "from" imports - by Anthony Sottile.

* bpo-37409: Ensure explicit relative imports from interactive
  sessions and scripts (having no parent package) always raise
  ImportError, rather than treating the current module as the package.
  Patch by Ben Lewis.

* bpo-37619: When adding a wrapper descriptor from one class to a
  different class (for example, setting "__add__ = str.__add__" on an
  "int" subclass), an exception is correctly raised when the operator
  is called.

* bpo-30773: Prohibit parallel running of aclose() / asend() /
  athrow(). Fix ag_running to reflect the actual running status of the
  AG.


库
--

* bpo-38319: 修复 套接字 和 shutil 模块中使用的sendfile() 在 32-bit
  架 构上会产生 OverflowError for files >= 2GiB . (补丁由Giampaolo
  Rodola 提供)

* bpo-38242: 回滚新的 asyncio Streams API

* bpo-38019: Correctly handle pause/resume reading of closed asyncio
  unix pipe.

* bpo-38163: Child mocks will now detect their type as either
  synchronous or asynchronous, asynchronous child mocks will be
  AsyncMocks and synchronous child mocks will be either MagicMock or
  Mock (depending on their parent type).

* bpo-38161: Removes _AwaitEvent from AsyncMock.

* bpo-38216: Allow the rare code that wants to send invalid http
  requests from the "http.client" library a way to do so.  The fixes
  for bpo-30458 led to breakage for some projects that were relying on
  this ability to test their own behavior in the face of bad requests.

* bpo-38108: Any synchronous magic methods on an AsyncMock now
  return a MagicMock. Any asynchronous magic methods on a MagicMock
  now return an AsyncMock.

* bpo-38248: asyncio: Fix inconsistent immediate Task cancellation

* bpo-38237: The arguments for the builtin pow function are more
  descriptive. They can now also be passed in as keywords.

* bpo-38191: Constructors of "NamedTuple" and "TypedDict" types now
  accept arbitrary keyword argument names, including "cls", "self",
  "typename", "_typename", "fields" and "_fields".  Passing positional
  arguments by keyword is deprecated.

* bpo-38185: Fixed case-insensitive string comparison in
  "sqlite3.Row" indexing.

* bpo-38136: Changes AsyncMock call count and await count to be two
  different counters. Now await count only counts when a coroutine has
  been awaited, not when it has been called, and vice-versa. Update
  the documentation around this.

* bpo-37828: Fix default mock name in
  "unittest.mock.Mock.assert_called()" exceptions. Patch by Abraham
  Toriz Cruz.

* bpo-38175: Fix a memory leak in comparison of "sqlite3.Row"
  objects.

* bpo-33936: _hashlib no longer calls obsolete OpenSSL
  initialization function with OpenSSL 1.1.0+.

* bpo-34706: Preserve subclassing in
  inspect.Signature.from_callable.

* bpo-38153: Names of hashing algorithms frome OpenSSL are now
  normalized to follow Python's naming conventions. For example
  OpenSSL uses sha3-512 instead of sha3_512 or blake2b512 instead of
  blake2b.

* bpo-38115: Fix a bug in dis.findlinestarts() where it would return
  invalid bytecode offsets. Document that a code object's co_lnotab
  can contain invalid bytecode offsets.

* bpo-38148: Add slots to "asyncio" transport classes, which can
  reduce memory usage.

* bpo-36991: Fixes a potential incorrect AttributeError exception
  escaping ZipFile.extract() in some unsupported input error
  situations.

* bpo-38134: Remove obsolete copy of PBKDF2_HMAC_fast. All supported
  OpenSSL versions contain a fast implementation.

* bpo-38132: The OpenSSL hashlib wrapper uses a simpler
  implementation. Several Macros and pointless caches are gone. The
  hash name now comes from OpenSSL's EVP. The algorithm name stays the
  same, except it is now always lower case.

* bpo-38008: Fix parent class check in protocols to correctly
  identify the module that provides a builtin protocol, instead of
  assuming they all come from the "collections.abc" module

* bpo-37405: Fixed regression bug for socket.getsockname() for non-
  CAN_ISOTP AF_CAN address family sockets by returning a 1-tuple
  instead of string.

* bpo-38121: Update parameter names on functions in
  importlib.metadata matching the changes in the 0.22 release of
  importlib_metadata.

* bpo-38110: The os.closewalk() implementation now uses the libc
  fdwalk() API on platforms where it is available.

* bpo-38093: Fixes AsyncMock so it doesn't crash when used with
  AsyncContextManagers or AsyncIterators.

* bpo-37488: Add warning to "datetime.utctimetuple()",
  "datetime.utcnow()" and "datetime.utcfromtimestamp()" .

* bpo-38086: Update importlib.metadata with changes from
  importlib_metadata 0.21.

* bpo-37251: Remove "__code__" check in AsyncMock that incorrectly
  evaluated function specs as async objects but failed to evaluate
  classes with "__await__" but no "__code__" attribute defined as
  async objects.

* bpo-38037: Fix reference counters in the "signal" module.

* bpo-38066: Hide internal asyncio.Stream methods: feed_eof(),
  feed_data(), set_exception() and set_transport().

* bpo-38059: inspect.py now uses sys.exit() instead of exit()

* bpo-37953: In "typing", improved the "__hash__" and "__eq__"
  methods for "ForwardReferences".

* bpo-38026: Fixed "inspect.getattr_static()" used "isinstance"
  while it should avoid dynamic lookup.

* bpo-38010: In "importlib.metadata" sync with "importlib_metadata"
  0.20, clarifying behavior of "files()" and fixing issue where only
  one requirement was returned for "requires()" on "dist-info"
  packages.

* bpo-38006: weakref.WeakValueDictionary defines a local remove()
  function used as callback for weak references. This function was
  created with a closure. Modify the implementation to avoid the
  closure.

* bpo-34410: Fixed a crash in the "tee()" iterator when re-enter it.
  RuntimeError is now raised in this case.

* bpo-37140: Fix a ctypes regression of Python 3.8. When a
  ctypes.Structure is passed by copy to a function, ctypes internals
  created a temporary object which had the side effect of calling the
  structure finalizer (__del__) twice. The Python semantics requires a
  finalizer to be called exactly once. Fix ctypes internals to no
  longer call the finalizer twice.

* bpo-37972: Subscripts to the "unittest.mock.call" objects now
  receive the same chaining mechanism as any other custom attributes,
  so that the following usage no longer raises a "TypeError":

  call().foo().__getitem__('bar')

  Patch by blhsing

* bpo-22347: Update mimetypes.guess_type to allow proper parsing of
  URLs with only a host name. Patch by Dong-hee Na.

* bpo-37885: venv: Don't generate unset variable warning on
  deactivate.

* bpo-37785: Fix xgettext warnings in "argparse".

* bpo-11953: Completing WSA* error codes in "socket".

* bpo-37424: Fixes a possible hang when using a timeout on
  "subprocess.run()" while capturing output.  If the child process
  spawned its own children or otherwise connected its stdout or stderr
  handles with another process, we could hang after the timeout was
  reached and our child was killed when attempting to read final
  output from the pipes.

* bpo-37212: "unittest.mock.call()" now preserves the order of
  keyword arguments in repr output. Patch by Karthikeyan Singaravelan.

* bpo-37305: Add .webmanifest -> application/manifest+json to list
  of recognized file types and content type headers

* bpo-21872: Fix "lzma": module decompresses data incompletely. When
  decompressing a FORMAT_ALONE format file, and it doesn't have the
  end marker, sometimes the last one to dozens bytes can't be output.
  Patch by Ma Lin.

* bpo-37206: Default values which cannot be represented as Python
  objects no longer improperly represented as "None" in function
  signatures.

* bpo-12144: Ensure cookies with "expires" attribute are handled in
  "CookieJar.make_cookies()".

* bpo-31163: pathlib.Path instance's rename and replace methods now
  return the new Path instance.

* bpo-25068: "urllib.request.ProxyHandler" now lowercases the keys
  of the passed dictionary.

* bpo-21315: Email headers containing RFC2047 encoded words are
  parsed despite the missing whitespace, and a defect registered. Also
  missing trailing whitespace after encoded words is now registered as
  a defect.

* bpo-36250: Ignore "ValueError" from "signal" with "interaction" in
  non-main thread.

* bpo-35168: "shlex.shlex.punctuation_chars" is now a read-only
  property.

* bpo-20504: Fixes a bug in "cgi" module when a multipart/form-data
  request has no "Content-Length" header.

* bpo-34519: Add additional aliases for HP Roman 8. Patch by Michael
  Osipov.


文档
----

* bpo-26868: Fix example usage of "PyModule_AddObject()" to properly
  handle errors.

* bpo-36797: Fix a dead link in the distutils API Reference.

* bpo-37977: Warn more strongly and clearly about pickle insecurity

* bpo-37937: Mention "frame.f_trace" in "sys.settrace()" docs.

* bpo-36260: Add decompression pitfalls to zipfile module
  documentation.

* bpo-36960: Restructured the "datetime" docs in the interest of
  making them more user-friendly and improving readability. Patch by
  Brad Solomon.

* bpo-23460: The documentation for decimal string formatting using
  the ":g" specifier has been updated to reflect the correct
  exponential notation cutoff point. Original patch contributed by
  Tuomas Suutari.

* bpo-35803: Document and test that "tempfile" functions may accept
  a *path-like object* for the "dir" argument.  Patch by Anthony
  Sottile.

* bpo-33944: Added a note about the intended use of code in .pth
  files.

* bpo-34293: Fix the Doc/Makefile regarding PAPER environment
  variable and PDF builds


测试
----

* bpo-38239: Fix test_gdb for Link Time Optimization (LTO) builds.

* bpo-38275: test_ssl now handles disabled TLS/SSL versions better.
  OpenSSL's crypto policy and run-time settings are recognized and
  tests for disabled versions are skipped. Tests also accept more TLS
  minimum_versions for platforms that override OpenSSL's default with
  strict settings.

* bpo-38271: The private keys for test_ssl were encrypted with 3DES
  in traditional PKCS#5 format. 3DES and the digest algorithm of
  PKCS#5 are blocked by some strict crypto policies. Use PKCS#8 format
  with AES256 encryption instead.

* bpo-38270: test.support now has a helper function to check for
  availibility of a hash digest function. Several tests are refactored
  avoid MD5 and use SHA256 instead. Other tests are marked to use MD5
  and skipped when MD5 is disabled.

* bpo-37123: Multiprocessing test test_mymanager() now also expects
  -SIGTERM, not only exitcode 0. BaseManager._finalize_manager() sends
  SIGTERM to the manager process if it takes longer than 1 second to
  stop, which happens on slow buildbots.

* bpo-38212: Multiprocessing tests: increase
  test_queue_feeder_donot_stop_onexc() timeout from 1 to 60 seconds.

* bpo-38117: Test with OpenSSL 1.1.1d

* bpo-37531: Enhance regrtest multiprocess timeout: write a message
  when killing a worker process, catch popen.kill() and popen.wait()
  exceptions, put a timeout on the second call to popen.communicate().

* bpo-37876: Add tests for ROT-13 codec.

* bpo-37252: Fix assertions in "test_close" and
  "test_events_mask_overflow" devpoll tests.

* bpo-34001: Make test_ssl pass with LibreSSL. LibreSSL handles
  minimum and maximum TLS version differently than OpenSSL.

* bpo-36919: Make "test_source_encoding.test_issue2301"
  implementation independent. The test will work now for both CPython
  and IronPython.

* bpo-34596: Fallback to a default reason when "unittest.skip()" is
  uncalled. Patch by Naitree Zhu.


构建
----

* bpo-38301: In Solaris family, we must be sure to use
  "-D_REENTRANT". Patch by Jesús Cea Avión.

* bpo-36210: Update optional extension module detection for AIX.
  ossaudiodev and spwd are not applicable for AIX, and are no longer
  reported as missing. 3rd-party packaging of ncurses (with ASIS
  support) conflicts with officially supported AIX curses library, so
  configure AIX to use libcurses.a. However, skip trying to build
  _curses_panel.

  patch by M Felt

* bpo-36002: Locate "llvm-profdata" and "llvm-ar" binaries using
  "AC_PATH_TOOL" rather than "AC_PATH_TARGET_TOOL".

* bpo-37936: The ".gitignore" file systematically keeps "rooted",
  with a non-trailing slash, all the rules that are meant to apply to
  files in a specific place in the repo.  Previously, when the
  intended file to ignore happened to be at the root of the repo, we'd
  most often accidentally also ignore files and directories with the
  same name anywhere in the tree.

* bpo-37936: The ".gitignore" file no longer applies to any files
  that are in fact tracked in the Git repository.  Patch by Greg
  Price.


Windows
-------

* bpo-38117: Update bundled OpenSSL to 1.1.1d

* bpo-38092: Reduce overhead when using multiprocessing in a Windows
  virtual environment.

* bpo-38133: Allow py.exe launcher to locate installations from the
  Microsoft Store and improve display of active virtual environments.

* bpo-38114: The "pip.ini" is no longer included in the Nuget
  package.

* bpo-36634: "os.cpu_count()" now returns active processors rather
  than maximum processors.

* bpo-36634: venv activate.bat now works when the existing variables
  contain double quote characters.

* bpo-38081: Prevent error calling "os.path.realpath()" on "'NUL'".

* bpo-38087: Fix case sensitivity in test_pathlib and test_ntpath.

* bpo-38088: Fixes distutils not finding vcruntime140.dll with only
  the v142 toolset installed.

* bpo-37283: Ensure command-line and unattend.xml setting override
  previously detected states in Windows installer.

* bpo-38030: Fixes "os.stat()" failing for block devices on Windows

* bpo-38020: Fixes potential crash when calling "os.readlink()" (or
  indirectly through "realpath()") on a file that is not a supported
  link.

* bpo-37705: Improve the implementation of "winerror_to_errno()".

* bpo-37702: Fix memory leak on Windows in creating an SSLContext
  object or running urllib.request.urlopen('https://...').

* bpo-37445: Include the "FORMAT_MESSAGE_IGNORE_INSERTS" flag in
  "FormatMessageW()" calls.

* bpo-37380: Don't collect unfinished processes with
  "subprocess._active" on Windows to cleanup later. Patch by Ruslan
  Kuprieiev.

* bpo-32587: Make "winreg.REG_MULTI_SZ" support zero-length strings.


macOS
-----

* bpo-38117: 更新MacOS installer中的OpenSSL为1.1.1d.

* bpo-38089: Move Azure Pipelines to latest VM versions and make
  macOS tests optional


IDLE
----

* bpo-35379: When exiting IDLE, catch any AttributeError.  One
  happens when EditorWindow.close is called twice.  Printing a
  traceback, when IDLE is run from a terminal, is useless and
  annoying.

* bpo-38183: To avoid problems, test_idle ignores the user config
  directory. It no longer tries to create or access .idlerc or any
  files within. Users must run IDLE to discover problems with saving
  settings.

* bpo-38077: IDLE no longer adds 'argv' to the user namespace when
  initializing it.  This bug only affected 3.7.4 and 3.8.0b2 to
  3.8.0b4.

* bpo-38041: Shell restart lines now fill the window width, always
  start with '=', and avoid wrapping unnecessarily. The line will
  still wrap if the included file name is long relative to the width.

* bpo-35771: To avoid occasional spurious test_idle failures on
  slower machines, increase the "hover_delay" in test_tooltip.

* bpo-37902: Add mousewheel scrolling for IDLE module, path, and
  stack browsers. Patch by George Zhang.


工具/示例
---------

* bpo-37803: pdb's "--help" and "--version" long options now work.

* bpo-37064: Add option -k to pathscript.py script: preserve shebang
  flags. Add option -a to pathscript.py script: add flags.


C API
-----

* bpo-38234: "Py_SetPath()" now sets "sys.executable" to the program
  full path ("Py_GetProgramFullPath()") rather than to the program
  name ("Py_GetProgramName()").

* bpo-38234: Python ignored arguments passed to "Py_SetPath()",
  "Py_SetPythonHome()" and "Py_SetProgramName()": fix Python
  initialization to use specified arguments.

* bpo-38205: The "Py_UNREACHABLE()" macro now calls
  "Py_FatalError()".

* bpo-37879: Fix subtype_dealloc to suppress the type decref when
  the base type is a C heap type


Python 3.8.0 beta 4
===================

*Release date: 2019-08-29*


安全
----

* bpo-34155: Fix parsing of invalid email addresses with more than
  one "@" (e.g. a@b@c.com.) to not return the part before 2nd "@" as
  valid email address. Patch by maxking & jpic.


核心与内置
----------

* bpo-37947: Adjust correctly the recursion level in the symtable
  generation for named expressions. Patch by Pablo Galindo.

* bpo-37830: Fixed compilation of "break" and "continue" in the
  "finally" block when the corresponding "try" block contains "return"
  with a non-constant value.

* bpo-32912: Reverted bpo-32912: emitting "SyntaxWarning" instead of
  "DeprecationWarning" for invalid escape sequences in string and
  bytes literals.

* bpo-37757: **PEP 572**: As described in the PEP, assignment
  expressions now raise "SyntaxError" when their interaction with
  comprehension scoping results in an ambiguous target scope.

  The "TargetScopeError" subclass originally proposed by the PEP has
  been removed in favour of just raising regular syntax errors for the
  disallowed cases.

* bpo-36311: Decoding bytes objects larger than 2GiB is faster and
  no longer fails when a multibyte characters spans a chunk boundary.

* bpo-37433: Fix "SyntaxError" indicator printing too many spaces
  for multi-line strings - by Anthony Sottile.

* bpo-20523: "pdb.Pdb" supports ~/.pdbrc in Windows 7. Patch by Tim
  Hopper and Dan Lidral-Porter.


库
--

* bpo-37834: Prevent shutil.rmtree exception when built on non-
  Windows system without fd system call support, like older versions
  of macOS.

* bpo-37965: Fix C compiler warning caused by
  distutils.ccompiler.CCompiler.has_function.

* bpo-37960: "repr()" of buffered and text streams now silences only
  expected exceptions when get the value of "name" and "mode"
  attributes.

* bpo-37951: Most features of the subprocess module now work again
  in subinterpreters. Only *preexec_fn* is restricted in
  subinterpreters.

* bpo-36205: Fix the rusage implementation of time.process_time() to
  correctly report the sum of the system and user CPU time.

* bpo-37950: Fix "ast.dump()" when call with incompletely
  initialized node.

* bpo-34679: Restores instantiation of Windows IOCP event loops from
  the non-main thread.

* bpo-36917: Add default implementation of the
  "ast.NodeVisitor.visit_Constant()" method which emits a deprecation
  warning and calls corresponding methody "visit_Num()",
  "visit_Str()", etc.

* bpo-37798: Update test_statistics.py to verify that the statistics
  module works well for both C and Python implementations. Patch by
  Dong-hee Na

* bpo-26589: Added a new status code to the http module: 451
  UNAVAILABLE_FOR_LEGAL_REASONS

* bpo-37915: Fix a segmentation fault that appeared when comparing
  instances of "datetime.timezone" and "datetime.tzinfo" objects.
  Patch by Pablo Galindo.

* bpo-37868: Fix dataclasses.is_dataclass when given an instance
  that never raises AttributeError in __getattr__.  That is, an object
  that returns something for __dataclass_fields__ even if it's not a
  dataclass.

* bpo-37811: Fix "socket" module's "socket.connect(address)"
  function being unable to establish connection in case of interrupted
  system call. The problem was observed on all OSes which "poll(2)"
  system call can take only non-negative integers and -1 as a timeout
  value.

* bpo-21131: Fix "faulthandler.register(chain=True)" stack.
  faulthandler now allocates a dedicated stack of "SIGSTKSZ*2" bytes,
  instead of just "SIGSTKSZ" bytes. Calling the previous signal
  handler in faulthandler signal handler uses more than "SIGSTKSZ"
  bytes of stack memory on some platforms.

* bpo-37798: Add C fastpath for statistics.NormalDist.inv_cdf()
  Patch by Dong-hee Na

* bpo-37819: Add Fraction.as_integer_ratio() to match the
  corresponding methods in bool, int, float, and decimal.

* bpo-37810: Fix "difflib" "?" hint in diff output when dealing with
  tabs.  Patch by Anthony Sottile.

* bpo-37772: In "zipfile.Path", when adding implicit dirs, ensure
  that ancestral directories are added and that duplicates are
  excluded.

* bpo-28292: Mark calendar.py helper functions as being private.
  The follows PEP 8 guidance to maintain the style conventions in the
  module and it addresses a known case of user confusion.

* bpo-18049: Add definition of THREAD_STACK_SIZE for AIX in
  Python/thread_pthread.h The default thread stacksize caused crashes
  with the default recursion limit Patch by M Felt

* bpo-37738: Fix the implementation of curses "addch(str,
  color_pair)": pass the color pair to "setcchar()", instead of always
  passing 0 as the color pair.

* bpo-37723: Fix performance regression on regular expression
  parsing with huge character sets. Patch by Yann Vaginay.

* bpo-32178: Fix IndexError in "email" package when trying to parse
  invalid address fields starting with ":".

* bpo-37685: Fixed comparisons of "datetime.timedelta" and
  "datetime.timezone".

* bpo-37695: Correct "curses.unget_wch()" error message.  Patch by
  Anthony Sottile.

* bpo-37354: Make Activate.ps1 Powershell script static to allow for
  signing it.

* bpo-37664: Update wheels bundled with ensurepip (pip 19.2.3 and
  setuptools 41.2.0)

* bpo-37642: Allowed the pure Python implementation of
  "datetime.timezone" to represent sub-minute offsets close to minimum
  and maximum boundaries, specifically in the ranges (23:59, 24:00)
  and (-23:59, 24:00). Patch by Ngalim Siregar

* bpo-16970: Adding a value error when an invalid value in passed to
  nargs Patch by Robert Leenders

* bpo-37587: Make json.loads faster for long strings. (Patch by
  Marco Paolini)

* bpo-18378: Recognize "UTF-8" as a valid value for LC_CTYPE in
  locale._parse_localename.

* bpo-37531: "python3 -m test -jN --timeout=TIMEOUT" now kills a
  worker process if it runs longer than *TIMEOUT* seconds.

* bpo-37482: Fix serialization of display name in originator or
  destination address fields with both encoded words and special
  chars.

* bpo-37372: Fix error unpickling datetime.time objects from Python
  2 with seconds>=24. Patch by Justin Blanchard.

* bpo-37085: Add the optional Linux SocketCAN Broadcast Manager
  constants, used as flags to configure the BCM behaviour, in the
  socket module.  Patch by Karl Ding.

* bpo-36871: Ensure method signature is used instead of constructor
  signature of a class while asserting mock object against method
  calls. Patch by Karthikeyan Singaravelan.

* bpo-36582: Fix "UserString.encode()" to correctly return "bytes"
  rather than a "UserString" instance.

* bpo-34775: Division handling of PurePath now returns
  NotImplemented instead of raising a TypeError when passed something
  other than an instance of str or PurePath. Patch by Roger Aiudi.


文档
----

* bpo-37979: Added a link to dateutil.parser.isoparse in the
  datetime.fromisoformat documentation. Patch by Paul Ganssle

* bpo-37759: Beginning edits to Whatsnew 3.8

* bpo-37726: Stop recommending getopt in the tutorial for command
  line argument parsing and promote argparse.

* bpo-37256: Fix wording of arguments for "Request" in
  "urllib.request"

* bpo-37004: In the documentation for difflib, a note was added
  explicitly warning that the results of SequenceMatcher's ratio
  method may depend on the order of the input strings.

* bpo-36487: Make C-API docs clear about what the "main" interpreter
  is.


测试
----

* bpo-37805: Add tests for json.dump(..., skipkeys=True). Patch by
  Dong-hee Na.


构建
----

* bpo-37707: Mark some individual tests to skip when --pgo is used.
  The tests marked increase the PGO task time significantly and likely
  don't help improve optimization of the final executable.


Windows
-------

* bpo-37549: "os.dup()" no longer fails for standard streams on
  Windows 7.

* bpo-1311: The "nul" file on Windows now returns True from
  "exists()" and a valid result from "os.stat()" with "S_IFCHR" set.

* bpo-9949: Enable support for following symlinks in
  "os.realpath()".

* bpo-37834: Treat all name surrogate reparse points on Windows in
  "os.lstat()" and other reparse points as regular files in
  "os.stat()".

* bpo-36266: Add the module name in the formatted error message when
  DLL load fail happens during module import in
  "_PyImport_FindSharedFuncptrWindows()". Patch by Srinivas Nyayapati.

* bpo-25172: Trying to import the "crypt" module on Windows will
  result in an "ImportError" with a message explaining that the module
  isn't supported on Windows. On other platforms, if the underlying
  "_crypt" module is not available, the ImportError will include a
  message explaining the problem.

* bpo-37778: Fixes the icons used for file associations to the
  Microsoft Store package.

* bpo-37734: Fix use of registry values to launch Python from
  Microsoft Store app.

* bpo-28269: Replace use of "strcasecmp()" for the system function
  "_stricmp()". Patch by Minmin Gong.


macOS
-----

* bpo-18049: Increase the default stack size of threads from 5MB to
  16MB on macOS, to match the stack size of the main thread. This
  avoids crashes on deep recursion in threads.


IDLE
----

* bpo-37824: Properly handle user input warnings in IDLE shell.
  Cease turning SyntaxWarnings into SyntaxErrors.

* bpo-37929: IDLE Settings dialog now closes properly when there is
  no shell window.

* bpo-37849: Fixed completions list appearing too high or low when
  shown above the current line.

* bpo-36419: Refactor IDLE autocomplete and improve testing.

* bpo-37748: Reorder the Run menu.  Put the most common choice, Run
  Module, at the top.


工具/示例
---------

* bpo-37942: Improve ArgumentClinic converter for floats.

* bpo-37034: Argument Clinic now uses the argument name on errors
  with keyword-only argument instead of their position. Patch
  contributed by Rémi Lapeyre.


C API
-----

* bpo-36763: Options added by "PySys_AddXOption()" are now handled
  the same way than "PyConfig.xoptions" and command line "-X" options.

* bpo-37926: Fix a crash in "PySys_SetArgvEx(0, NULL, 0)".


Python 3.8.0 beta 3
===================

*Release date: 2019-07-29*


安全
----

* bpo-37461: Fix an infinite loop when parsing specially crafted
  email headers. Patch by Abhilash Raj.


核心与内置
----------

* bpo-37593: Swap the positions of the *posonlyargs* and *args*
  parameters in the constructor of "ast.parameters" nodes.

* bpo-36974: Implemented separate vectorcall functions for every
  calling convention of builtin functions and methods. This improves
  performance for calls.


库
--

* bpo-37697: Syncronize "importlib.metadata" with importlib_metadata
  0.19, improving handling of EGG-INFO files and fixing a crash when
  entry point names contained colons.

* bpo-37691: Let math.dist() accept coordinates as sequences (or
  iterables) rather than just tuples.

* bpo-37664: Update wheels bundled with ensurepip (pip 19.2.1 and
  setuptools 41.0.1)

* bpo-36324: Make internal attributes for statistics.NormalDist()
  private.

* bpo-37491: Fix "IndexError" when parsing email headers with
  unexpectedly ending bare-quoted string value. Patch by Abhilash Raj.

* bpo-37579: Return "NotImplemented" in Python implementation of
  "__eq__" for "timedelta" and "time" when the other object being
  compared is not of the same type to match C implementation. Patch by
  Karthikeyan Singaravelan.

* bpo-21478: Record calls to parent when autospecced object is
  attached to a mock using "unittest.mock.attach_mock()". Patch by
  Karthikeyan Singaravelan.

* bpo-37502: pickle.loads() no longer raises TypeError when the
  buffers argument is set to None

* bpo-37520: Correct behavior for zipfile.Path.parent when the path
  object identifies a subdirectory.

* bpo-18374: Fix the ".col_offset" attribute of nested "ast.BinOp"
  instances which had a too large value in some situations.

* bpo-37421: Fix "multiprocessing.util.get_temp_dir()" finalizer:
  clear also the 'tempdir' configuration of the current process, so
  next call to "get_temp_dir()" will create a new temporary directory,
  rather than reusing the removed temporary directory.

* bpo-37481: The distutils "bdist_wininst" command is deprecated in
  Python 3.8, use "bdist_wheel" (wheel packages) instead.

* bpo-26967: An "ArgumentParser" with "allow_abbrev=False" no longer
  disables grouping of short flags, such as "-vv", but only disables
  abbreviation of long flags as documented. Patch by Zac Hatfield-
  Dodds.

* bpo-37347: "sqlite3.Connection.create_aggregate()",
  "sqlite3.Connection.create_function()",
  "sqlite3.Connection.set_authorizer()",
  "sqlite3.Connection.set_progress_handler()"
  "sqlite3.Connection.set_trace_callback()" methods lead to segfaults
  if some of these methods are called twice with an equal object but
  not the same. Now callbacks are stored more carefully. Patch by
  Aleksandr Balezin.

* bpo-36564: Fix infinite loop in email header folding logic that
  would be triggered when an email policy's max_line_length is not
  long enough to include the required markup and any values in the
  message. Patch by Paul Ganssle


文档
----

* bpo-32910: Remove implementation-specific behaviour of how venv's
  Deactivate works.

* bpo-37284: Add a brief note to indicate that any new
  "sys.implementation" required attributes must go through the PEP
  process.

* bpo-30088: Documented that "mailbox.Maildir" constructor doesn't
  attempt to verify the maildir folder layout correctness. Patch by
  Sviatoslav Sydorenko.

* bpo-37521: Fix "importlib" examples to insert any newly created
  modules via importlib.util.module_from_spec() immediately into
  sys.modules instead of after calling loader.exec_module().

  Thanks to Benjamin Mintz for finding the bug.

* bpo-37456: Slash ('/') is now part of syntax.

* bpo-37487: Fix PyList_GetItem index description to include 0.

* bpo-37149: Replace the dead link to the Tkinter 8.5 reference by
  John Shipman, New Mexico Tech, with a link to the archive.org copy.

* bpo-37478: Added possible exceptions to the description of
  os.chdir().


测试
----

* bpo-37558: Fix
  test_shared_memory_cleaned_after_process_termination name handling

* bpo-37526: Add "test.support.catch_threading_exception()": context
  manager catching "threading.Thread" exception using
  "threading.excepthook()".

* bpo-37421: test_concurrent_futures now explicitly stops the
  ForkServer instance if it's running.

* bpo-37421: multiprocessing tests now stop the ForkServer instance
  if it's running: close the "alive" file descriptor to ask the server
  to stop and then remove its UNIX address.


构建
----

* bpo-36044: Reduce the number of unit tests run for the PGO
  generation task.  This speeds up the task by a factor of about 15x.
  Running the full unit test suite is slow.  This change may result in
  a slightly less optimized build since not as many code branches will
  be executed.  If you are willing to wait for the much slower build,
  the old behavior can be restored using './configure [..]
  PROFILE_TASK="-m test --pgo-extended"'. We make no guarantees as to
  which PGO task set produces a faster build. Users who care should
  run their own relevant benchmarks as results can depend on the
  environment, workload, and compiler tool chain.


Windows
-------

* bpo-37672: Switch Windows Store package's pip to use bundled
  "pip.ini" instead of "PIP_USER" variable.


IDLE
----

* bpo-37692: Improve highlight config sample with example shell
  interaction and better labels for shell elements.

* bpo-37628: Settings dialog no longer expands with font size.

* bpo-37627: Initialize the Customize Run dialog with the command
  line arguments most recently entered before.  The user can
  optionally edit before submitting them.

* bpo-33610: Fix code context not showing the correct context when
  first toggled on.

* bpo-37530: Optimize code context to reduce unneeded background
  activity. Font and highlight changes now occur along with text
  changes instead of after a random delay.

* bpo-27452: Cleanup "config.py" by inlining "RemoveFile" and
  simplifying the handling of "file" in "CreateConfigHandlers".

* bpo-17535: Add optional line numbers for IDLE editor windows.
  Windows open without line numbers unless set otherwise in the
  General tab of the configuration dialog.

* bpo-26806: To compensate for stack frames added by IDLE and avoid
  possible problems with low recursion limits, add 30 to limits in the
  user code execution process.  Subtract 30 when reporting recursion
  limits to make this addition mostly transparent.

* bpo-36390: Gather Format menu functions into format.py.  Combine
  paragraph.py, rstrip.py, and format methods from editor.py.


工具/示例
---------

* bpo-37675: 2to3 now works when run from a zipped standard library.


Python 3.8.0 beta 2
===================

*Release date: 2019-07-04*


安全
----

* bpo-37363: Adds audit events for the range of supported run
  commands (see 命令行与环境).

* bpo-37463: ssl.match_hostname() no longer accepts IPv4 addresses
  with additional text after the address and only quad-dotted notation
  without trailing whitespaces. Some inet_aton() implementations
  ignore whitespace and all data after whitespace, e.g. '127.0.0.1
  whatever'.

* bpo-37363: Adds audit events for "ensurepip", "ftplib", "glob",
  "imaplib", "nntplib", "pdb", "poplib", "shutil", "smtplib",
  "sqlite3", "subprocess", "telnetlib", "tempfile" and "webbrowser",
  as well as "os.listdir()", "os.scandir()" and "breakpoint()".

* bpo-37364: "io.open_code()" is now used when reading ".pth" files.

* bpo-34631: Updated OpenSSL to 1.1.1c in Windows installer


核心与内置
----------

* bpo-37467: Fix "sys.excepthook()" and "PyErr_Display()" if a
  filename is a bytes string. For example, for a SyntaxError exception
  where the filename attribute is a bytes string.

* bpo-37417: "bytearray.extend()" now correctly handles errors that
  arise during iteration. Patch by Brandt Bucher.

* bpo-24214: Improved support of the surrogatepass error handler in
  the UTF-8 and UTF-16 incremental decoders.

* bpo-35224: Reverse evaluation order of key: value in dict
  comprehensions as proposed in PEP 572. I.e. in "{k: v for ...}", "k"
  will be evaluated before "v".

* bpo-37316: Fix the "PySys_Audit()" call in "mmap.mmap".

* bpo-37269: Fix a bug in the peephole optimizer that was not
  treating correctly constant conditions with binary operators. Patch
  by Pablo Galindo.

* bpo-37213: Handle correctly negative line offsets in the peephole
  optimizer. Patch by Pablo Galindo.

* bpo-37219: Remove errorneous optimization for empty set
  differences.

* bpo-36922: Slot functions optimize any callable with
  "Py_TPFLAGS_METHOD_DESCRIPTOR" instead of only instances of
  "function".

* bpo-36974: The slot "tp_vectorcall_offset" is inherited
  unconditionally to support "super().__call__()" when the base class
  uses vectorcall.

* bpo-37160: "threading.get_native_id()" now also supports NetBSD.

* bpo-37077: Add "threading.get_native_id()" support for AIX. Patch
  by M. Felt


库
--

* bpo-37440: http.client now enables TLS 1.3 post-handshake
  authentication for default context or if a cert_file is passed to
  HTTPSConnection.

* bpo-37437: Update vendorized expat version to 2.2.7.

* bpo-37428: SSLContext.post_handshake_auth = True no longer sets
  SSL_VERIFY_POST_HANDSHAKE verify flag for client connections.
  Although the option is documented as ignored for clients, OpenSSL
  implicitly enables cert chain validation when the flag is set.

* bpo-37420: "os.sched_setaffinity()" now correctly handles errors
  that arise during iteration over its "mask" argument. Patch by
  Brandt Bucher.

* bpo-37412: The "os.getcwdb()" function now uses the UTF-8 encoding
  on Windows, rather than the ANSI code page: see **PEP 529** for the
  rationale. The function is no longer deprecated on Windows.

* bpo-29412: Fix IndexError in parsing a header value ending
  unexpectedly. Patch by Abhilash Raj.

* bpo-36546: The *dist* argument for statistics.quantiles() is now
  positional only. The current name doesn't reflect that the argument
  can be either a dataset or a distribution.  Marking the parameter as
  positional avoids confusion and makes it possible to change the name
  later.

* bpo-37394: Fix a bug that was causing the "queue" module to fail
  if the accelerator module was not available. Patch by Pablo Galindo.

* bpo-33972: Email with single part but content-type set to
  "multipart/*" doesn't raise AttributeError anymore.

* bpo-37280: Use threadpool for reading from file for sendfile
  fallback mode.

* bpo-37279: Fix asyncio sendfile support when sendfile sends extra
  data in fallback mode.

* bpo-19865: "ctypes.create_unicode_buffer()" now also supports non-
  BMP characters on platforms with 16-bit "wchar_t" (for example,
  Windows and AIX).

* bpo-37210: Allow pure Python implementation of "pickle" to work
  even when the C "_pickle" module is unavailable.

* bpo-35922: Fix "RobotFileParser.crawl_delay()" and
  "RobotFileParser.request_rate()" to return "None" rather than raise
  "AttributeError" when no relevant rule is defined in the robots.txt
  file.  Patch by Rémi Lapeyre.

* bpo-35766: Change the format of feature_version to be a (major,
  minor) tuple.

* bpo-36607: Eliminate "RuntimeError" raised by
  "asyncio.all_tasks()" if internal tasks weak set is changed by
  another thread during iteration.

* bpo-18748: "_pyio.IOBase" destructor now does nothing if getting
  the "closed" attribute fails to better mimick "_io.IOBase"
  finalizer.

* bpo-36402: Fix a race condition at Python shutdown when waiting
  for threads. Wait until the Python thread state of all non-daemon
  threads get deleted (join all non-daemon threads), rather than just
  wait until non-daemon Python threads complete.

* bpo-34886: Fix an unintended ValueError from "subprocess.run()"
  when checking for conflicting "input" and "stdin" or
  "capture_output" and "stdout" or "stderr" args when they were
  explicitly provided but with "None" values within a passed in
  "**kwargs" dict rather than as passed directly by name. Patch
  contributed by Rémi Lapeyre.

* bpo-37173: The exception message for "inspect.getfile()" now
  correctly reports the passed class rather than the builtins module.

* bpo-37178: Give math.perm() a one argument form that means the
  same as math.factorial().

* bpo-37178: For math.perm(n, k), let k default to n, giving the
  same result as factorial.

* bpo-37163: Deprecated passing "obj" argument of
  "dataclasses.replace()" as keyword argument.

* bpo-37165: Converted _collections._count_elements to use the
  Argument Clinic.

* bpo-34767: Do not always create a "collections.deque" in
  "asyncio.Lock".

* bpo-37158: Speed-up statistics.fmean() by switching from a
  function to a generator.

* bpo-37150: "argparse._ActionsContainer.add_argument" now throws
  error, if someone accidentally pass FileType class object instead of
  instance of FileType as "type" argument

* bpo-35621: Support running asyncio subprocesses when execution
  event loop in a thread on UNIX.

* bpo-36520: Lengthy email headers with UTF-8 characters are now
  properly encoded when they are folded. Patch by Jeffrey Kintscher.

* bpo-30835: Fixed a bug in email parsing where a message with
  invalid bytes in content-transfer-encoding of a multipart message
  can cause an AttributeError. Patch by Andrew Donnellan.

* bpo-35805: Add parser for Message-ID header and add it to default
  HeaderRegistry. This should prevent folding of Message-ID using RFC
  2048 encoded words.

* bpo-35070: posix.getgrouplist() now works correctly when the user
  belongs to NGROUPS_MAX supplemental groups. Patch by Jeffrey
  Kintscher.

* bpo-32627: Fix compile error when "_uuid" headers conflicting
  included.

* bpo-11122: Distutils won't check for rpmbuild in specified paths
  only.

* bpo-4963: Fixed non-deterministic behavior related to mimetypes
  extension mapping and module reinitialization.


文档
----

* bpo-34903: Documented that in "datetime.datetime.strptime()", the
  leading zero in some two-digit formats is optional. Patch by Mike
  Gleen.


测试
----

* bpo-37421: test_distutils.test_build_ext() is now able to remove
  the temporary directory on Windows: don't import the newly built C
  extension ("xx") in the current process, but test it in a separated
  process.

* bpo-37421: test_concurrent_futures now cleans up multiprocessing
  to remove immediately temporary directories created by
  multiprocessing.util.get_temp_dir().

* bpo-37421: test_winconsoleio doesn't leak a temporary file
  anymore: use tempfile.TemporaryFile() to remove it when the test
  completes.

* bpo-37421: multiprocessing tests now explicitly call
  "_run_finalizers()" to immediately remove temporary directories
  created by tests.

* bpo-37199: Fix test failures when IPv6 is unavailable or disabled.

* bpo-37335: Remove no longer necessary code from c locale coercion
  tests

* bpo-37421: Fix test_shutil to no longer leak temporary files.

* bpo-37411: Fix test_wsgiref.testEnviron() to no longer depend on
  the environment variables (don't fail if "X" variable is set).

* bpo-37400: Fix test_os.test_chown(): use os.getgroups() rather
  than grp.getgrall() to get groups. Rename also the test to
  test_chown_gid().

* bpo-37359: Add --cleanup option to python3 -m test to remove
  "test_python_*" directories of previous failed jobs. Add "make
  cleantest" to run "python3 -m test --cleanup".

* bpo-37362: test_gdb no longer fails if it gets an "unexpected"
  message on stderr: it now ignores stderr. The purpose of test_gdb is
  to test that python-gdb.py commands work as expected, not to test
  gdb.

* bpo-35998: Avoid TimeoutError in test_asyncio:
  test_start_tls_server_1()

* bpo-37278: Fix test_asyncio ProactorLoopCtrlC: join the thread to
  prevent leaking a running thread and leaking a reference.

* bpo-37261: Fix "test.support.catch_unraisable_exception()": its
  __exit__() method now ignores unraisable exception raised when
  clearing its "unraisable" attribute.

* bpo-37169: Rewrite "_PyObject_IsFreed()" unit tests.

* bpo-37153: "test_venv.test_mutiprocessing()" now explicitly calls
  "pool.terminate()" to wait until the pool completes.

* bpo-28009: Modify the test_uuid logic to test when a program is
  available AND can be used to obtain a MACADDR as basis for an UUID.
  Patch by M. Felt


构建
----

* bpo-37189: Many "PyRun_XXX()" functions like "PyRun_String()" were
  no longer exported in "libpython38.dll" by mistake. Export them
  again to fix the ABI compatibiliy.


Windows
-------

* bpo-10945: Officially drop support for creating bdist_wininst
  installers on non-Windows systems.

* bpo-37369: Fixes path for "sys.executable" when running from the
  Microsoft Store.

* bpo-37351: Removes libpython38.a from standard Windows
  distribution.

* bpo-35360: Update Windows builds to use SQLite 3.28.0.

* bpo-37267: On Windows, "os.dup()" no longer creates an inheritable
  fd when handling a character file.

* bpo-36779: Ensure "time.tzname" is correct on Windows when the
  active code page is set to CP_UTF7 or CP_UTF8.


macOS
-----

* bpo-34602: Avoid test suite failures on macOS by no longer calling
  resource.setrlimit to increase the process stack size limit at
  runtime. The runtime change is no longer needed since the
  interpreter is being built with a larger default stack size.

* bpo-35360: Update macOS installer to use SQLite 3.28.0.

* bpo-34631: Updated OpenSSL to 1.1.1c in macOS installer.


IDLE
----

* bpo-37325: Fix tab focus traversal order for help source and
  custom run dialogs.

* bpo-37321: Both subprocess connection error messages now refer to
  the 'Startup failure' section of the IDLE doc.

* bpo-37177: Properly 'attach' search dialogs to their main window
  so that they behave like other dialogs and do not get hidden behind
  their main window.

* bpo-37039: Adjust "Zoom Height" to individual screens by
  momemtarily maximizing the window on first use with a particular
  screen. Changing screen settings may invalidate the saved height.
  While a window is maximized, "Zoom Height" has no effect.

* bpo-35763: Make calltip reminder about '/' meaning positional-only
  less obtrusive by only adding it when there is room on the first
  line.

* bpo-5680: Add 'Run... Customized' to the Run menu to run a module
  with customized settings.  Any 'command line arguments' entered are
  added to sys.argv. One can suppress the normal Shell main module
  restart.


C API
-----

* bpo-36763: Add "PyConfig_SetWideStringList()" function.

* bpo-28805: The "METH_FASTCALL" calling convention has been
  documented.

* bpo-37221: "tp_print" is put back at the end of the "PyTypeObject"
  structure to restore support for old code (in particular generated
  by Cython) setting "tp_print = 0". Note that "tp_print" will be
  removed entirely in Python 3.9.

* bpo-37221: The new function "PyCode_NewWithPosOnlyArgs()" allows
  to create code objects like "PyCode_New()", but with an extra
  *posonlyargcount* parameter for indicating the number of positonal-
  only arguments.

* bpo-37215: Fix dtrace issue introduce by bpo-36842

* bpo-37191: Python.h does not need compiler support for
  intermingled declarations (GCC's "-Wdeclaration-after-statement"),
  which were added in 3.8.0 Beta 1. Note that in Python 3.9,
  intermingled declarations will be needed again.

* bpo-37170: Fix the cast on error in
  "PyLong_AsUnsignedLongLongMask()".


Python 3.8.0 beta 1
===================

*Release date: 2019-06-04*


安全
----

* bpo-35907: CVE-2019-9948: Avoid file reading by disallowing
  "local- file://" and "local_file://" URL schemes in
  "URLopener().open()" and "URLopener().retrieve()" of
  "urllib.request".

* bpo-33529: Prevent fold function used in email header encoding
  from entering infinite loop when there are too many non-ASCII
  characters in a header.

* bpo-33164: Updated blake2 implementation which uses secure memset
  implementation provided by platform.


核心与内置
----------

* bpo-35814: Allow unpacking in the right hand side of annotated
  assignments. In particular, "t: Tuple[int, ...] = x, y, *z" is now
  allowed.

* bpo-37126: All structseq objects are now tracked by the garbage
  collector. Patch by Pablo Galindo.

* bpo-37122: Make the *co_argcount* attribute of code objects
  represent the total number of positional arguments (including
  positional-only arguments). The value of *co_posonlyargcount* can be
  used to distinguish which arguments are positional only, and the
  difference (*co_argcount* - *co_posonlyargcount*) is the number of
  positional-or-keyword arguments. Patch by Pablo Galindo.

* bpo-20092: Constructors of "int", "float" and "complex" will now
  use the "__index__()" special method, if available and the
  corresponding method "__int__()", "__float__()" or "__complex__()"
  is not available.

* bpo-37087: Add native thread ID (TID) support to OpenBSD.

* bpo-26219: Implemented per opcode cache mechanism and
  "LOAD_GLOBAL" instruction use it. "LOAD_GLOBAL" is now about 40%
  faster. Contributed by Yury Selivanov, and Inada Naoki.

* bpo-37072: Fix crash in PyAST_FromNodeObject() when flags is NULL.

* bpo-37029: Freeing a great many small objects could take time
  quadratic in the number of arenas, due to using linear search to
  keep "obmalloc.c"'s list of usable arenas sorted by order of number
  of free memory pools. This is accomplished without search now,
  leaving the worst-case time linear in the number of arenas.  For
  programs where this quite visibly matters (typically with more than
  100 thousand small objects alive simultaneously), this can greatly
  reduce the time needed to release their memory.

* bpo-26423: Fix possible overflow in "wrap_lenfunc()" when
  "sizeof(long) < sizeof(Py_ssize_t)" (e.g., 64-bit Windows).

* bpo-37050: Improve the AST for "debug" f-strings, which use '=' to
  print out the source of the expression being evaluated.  Delete
  expr_text from the FormattedValue node, and instead use a Constant
  string node (possibly merged with adjacent constant expressions
  inside the f-string).

* bpo-22385: The "bytes.hex", "bytearray.hex", and "memoryview.hex"
  methods as well as the "binascii.hexlify" and "b2a_hex" functions
  now have the ability to include an optional separator between hex
  bytes.  This functionality was inspired by MicroPython's hexlify
  implementation.

* bpo-26836: Add "os.memfd_create()".

* bpo-37032: Added new "replace()" method to the code type
  ("types.CodeType").

* bpo-37007: Implement "socket.if_nameindex()",
  "socket.if_nametoindex()", and "socket.if_indextoname()" on Windows.

* bpo-36829: "PyErr_WriteUnraisable()" now creates a traceback
  object if there is no current traceback. Moreover, call
  "PyErr_NormalizeException()" and "PyException_SetTraceback()" to
  normalize the exception value. Ignore any error.

* bpo-36878: Only accept text after "# type: ignore" if the first
  character is ASCII. This is to disallow things like "# type:
  ignoreé".

* bpo-36878: Store text appearing after a "# type: ignore" comment
  in the AST. For example a type ignore like "# type: ignore[E1000]"
  will have the string ""[E1000]"" stored in its AST node.

* bpo-2180: Treat line continuation at EOF as a "SyntaxError" by
  Anthony Sottile.

* bpo-36907: Fix a crash when calling a C function with a keyword
  dict ("f(**kwargs)") and changing the dict "kwargs" while that
  function is running.

* bpo-36946: Fix possible signed integer overflow when handling
  slices.

* bpo-36826: Add NamedExpression kind support to ast_unparse.c

* bpo-1875: A "SyntaxError" is now raised if a code blocks that will
  be optimized away (e.g. if conditions that are always false)
  contains syntax errors. Patch by Pablo Galindo.

* bpo-36027: Allow computation of modular inverses via three-
  argument "pow": the second argument is now permitted to be negative
  in the case where the first and third arguments are relatively
  prime.

* bpo-36861: Update the Unicode database to version 12.1.0.

* bpo-28866: Avoid caching attributes of classes which type defines
  mro() to avoid a hard cache invalidation problem.

* bpo-36851: The "FrameType" stack is now correctly cleaned up if
  the execution ends with a return and the stack is not empty.

* bpo-34616: The "compile()" builtin functions now support the
  "ast.PyCF_ALLOW_TOP_LEVEL_AWAIT" flag,  which allow to compile
  sources that  contains top-level "await", "async with" or "async
  for". This is useful to evaluate async-code from with an already
  async functions; for example in a custom REPL.

* bpo-36842: Implement PEP 578, adding sys.audit, io.open_code and
  related APIs.

* bpo-27639: Correct return type for UserList slicing operations.
  Patch by Michael Blahay, Erick Cervantes, and vaultah

* bpo-36737: Move PyRuntimeState.warnings into per-interpreter state
  (via "module state").

* bpo-36793: Removed "__str__" implementations from builtin types
  "bool", "int", "float", "complex" and few classes from the standard
  library. They now inherit "__str__()" from "object".

* bpo-36817: Add a "=" feature f-strings for debugging. This can
  precede "!s", "!r", or "!a". It produces the text of the expression,
  followed by an equal sign, followed by the repr of the value of the
  expression. So "f'{3*9+15=}'" would be equal to the string
  "'3*9+15=42'".  If "=" is specified, the default conversion is set
  to "!r", unless a format spec is given, in which case the formatting
  behavior is unchanged, and __format__ will be used.

* bpo-24048: Save the live exception during import.c's
  "remove_module()".

* bpo-27987: pymalloc returns memory blocks aligned by 16 bytes,
  instead of 8 bytes, on 64-bit platforms to conform x86-64 ABI.
  Recent compilers assume this alignment more often. Patch by Inada
  Naoki.

* bpo-36601: A long-since-meaningless check for "getpid() ==
  main_pid" was removed from Python's internal C signal handler.

* bpo-36594: Fix incorrect use of "%p" in format strings. Patch by
  Zackery Spytz.

* bpo-36045: builtins.help() now prefixes "async" for async
  functions

* bpo-36084: Add native thread ID (TID) to threading.Thread objects
  (supported platforms: Windows, FreeBSD, Linux, macOS)

* bpo-36035: Added fix for broken symlinks in combination with
  pathlib

* bpo-35983: Added new trashcan macros to deal with a double
  deallocation that could occur when the "tp_dealloc" of a subclass
  calls the "tp_dealloc" of a base class and that base class uses the
  trashcan mechanism. Patch by Jeroen Demeyer.

* bpo-20602: Do not clear "sys.flags" and "sys.float_info" during
  shutdown. Patch by Zackery Spytz.

* bpo-26826: Expose "copy_file_range()" as a low level API in the
  "os" module.

* bpo-32388: Remove cross-version binary compatibility requirement
  in tp_flags.

* bpo-31862: Port binascii to PEP 489 multiphase initialization.
  Patch by Marcel Plch.


库
--

* bpo-37128: Added "math.perm()".

* bpo-37120: Add SSLContext.num_tickets to control the number of
  TLSv1.3 session tickets.

* bpo-12202: Fix the error handling in
  "msilib.SummaryInformation.GetProperty()". Patch by Zackery Spytz.

* bpo-26835: The fcntl module now contains file sealing constants
  for sealing of memfds.

* bpo-29262: Add "get_origin()" and "get_args()" introspection
  helpers to "typing" module.

* bpo-12639: "msilib.Directory.start_component()" no longer fails if
  *keyfile* is not "None".

* bpo-36999: Add the "asyncio.Task.get_coro()" method to publicly
  expose the tasks's coroutine object.

* bpo-35246: Make "asyncio.create_subprocess_exec()" accept path-
  like arguments.

* bpo-35279: Change default *max_workers* of "ThreadPoolExecutor"
  from "cpu_count() * 5" to "min(32, cpu_count() + 4))".  Previous
  value was unreasonably large on many cores machines.

* bpo-37076: "_thread.start_new_thread()" now logs uncaught
  exception raised by the function using "sys.unraisablehook()",
  rather than "sys.excepthook()", so the hook gets access to the
  function which raised the exception.

* bpo-33725: On macOS, the "multiprocessing" module now uses *spawn*
  start method by default.

* bpo-37054: Fix destructor "_pyio.BytesIO" and
  "_pyio.TextIOWrapper": initialize their "_buffer" attribute as soon
  as possible (in the class body), because it's used by "__del__()"
  which calls "close()".

* bpo-37058: PEP 544: Add "Protocol" and "@runtime_checkable" to the
  "typing" module.

* bpo-36933: The functions "sys.set_coroutine_wrapper" and
  "sys.get_coroutine_wrapper" that were deprecated and marked for
  removal in 3.8 have been removed.

* bpo-37047: Handle late binding and attribute access in
  "unittest.mock.AsyncMock" setup for autospeccing. Document newly
  implemented async methods in "unittest.mock.MagicMock".

* bpo-37049: PEP 589: Add "TypedDict" to the "typing" module.

* bpo-37046: PEP 586: Add "Literal" to the "typing" module.

* bpo-37045: PEP 591: Add "Final" qualifier and "@final" decorator
  to the "typing" module.

* bpo-37035: Don't log OSError based exceptions if a fatal error has
  occurred in asyncio transport. Peer can generate almost any OSError,
  user cannot avoid these exceptions by fixing own code. Errors are
  still propagated to user code, it's just logging them is pointless
  and pollute asyncio logs.

* bpo-37001: "symtable.symtable()" now accepts the same input types
  for source code as the built-in "compile()" function. Patch by Dino
  Viehland.

* bpo-37028: Implement asyncio REPL

* bpo-37027: Return safe to use proxy socket object from
  transport.get_extra_info('socket')

* bpo-32528: Make asyncio.CancelledError a BaseException.

  This will address the common mistake many asyncio users make: an
  "except Exception" clause breaking Tasks cancellation.

  In addition to this change, we stop inheriting asyncio.TimeoutError
  and asyncio.InvalidStateError from their concurrent.futures.*
  counterparts. There's no point for these exceptions to share the
  inheritance chain.

* bpo-1230540: Add a new "threading.excepthook()" function which
  handles uncaught "threading.Thread.run()" exception. It can be
  overridden to control how uncaught "threading.Thread.run()"
  exceptions are handled.

* bpo-36996: Handle "unittest.mock.patch()" used as a decorator on
  async functions.

* bpo-37008: Add support for calling "next()" with the mock
  resulting from "unittest.mock.mock_open()"

* bpo-27737: Allow whitespace only header encoding in "email.header"
  - by Batuhan Taskaya

* bpo-36969: PDB command "args" now  display positional only
  arguments. Patch contributed by Rémi Lapeyre.

* bpo-36969: PDB command "args" now  display keyword only arguments.
  Patch contributed by Rémi Lapeyre.

* bpo-36983: Add missing names to "typing.__all__": "ChainMap",
  "ForwardRef", "OrderedDict" - by Anthony Sottile.

* bpo-36972: Add SupportsIndex protocol to the typing module to
  allow type checking to detect classes that can be passed to "hex()",
  "oct()" and "bin()".

* bpo-32972: Implement "unittest.IsolatedAsyncioTestCase" to help
  testing asyncio-based code.

* bpo-36952: "fileinput.input()" and "fileinput.FileInput"
  **bufsize** argument has been removed (was deprecated and ignored
  since Python 3.6), and as a result the **mode** and **openhook**
  arguments have been made keyword-only.

* bpo-36952: Starting with Python 3.3, importing ABCs from
  "collections" is deprecated, and import should be done from
  "collections.abc". Still being able to import from "collections" was
  marked for removal in 3.8, but has been delayed to 3.9;
  documentation and "DeprecationWarning" clarified.

* bpo-36949: Implement __repr__ for WeakSet objects.

* bpo-36948: Fix "NameError" in
  "urllib.request.URLopener.retrieve()". Patch by Karthikeyan
  Singaravelan.

* bpo-33524: Fix the folding of email header when the
  max_line_length is 0 or None and the header contains non-ascii
  characters. Contributed by Licht Takeuchi (@Licht-T).

* bpo-24564: "shutil.copystat()" now ignores "errno.EINVAL" on
  "os.setxattr()" which may occur when copying files on filesystems
  without extended attributes support.

  Original patch by Giampaolo Rodola, updated by Ying Wang.

* bpo-36888: Python child processes can now access the status of
  their parent process using multiprocessing.process.parent_process

* bpo-36921: Deprecate "@coroutine" for sake of "async def".

* bpo-25652: Fix bug in "__rmod__" of "UserString" - by Batuhan
  Taskaya.

* bpo-36916: Remove a message about an unhandled exception in a task
  when writer.write() is used without await and writer.drain() fails
  with an exception.

* bpo-36889: Introduce "asyncio.Stream" class that merges
  "asyncio.StreamReader" and "asyncio.StreamWriter" functionality.
  "asyncio.Stream" can work in readonly, writeonly and readwrite
  modes. Provide "asyncio.connect()", "asyncio.connect_unix()",
  "asyncio.connect_read_pipe()" and "asyncio.connect_write_pipe()"
  factories to open "asyncio.Stream" connections. Provide
  "asyncio.StreamServer" and "UnixStreamServer" to serve servers with
  asyncio.Stream API. Modify "asyncio.create_subprocess_shell()" and
  "asyncio.create_subprocess_exec()" to use "asyncio.Stream" instead
  of deprecated "StreamReader" and "StreamWriter". Deprecate
  "asyncio.StreamReader" and "asyncio.StreamWriter". Deprecate usage
  of private classes, e.g. "asyncio.FlowControlMixing" and
  "asyncio.StreamReaderProtocol" outside of asyncio package.

* bpo-36845: Added validation of integer prefixes to the
  construction of IP networks and interfaces in the ipaddress module.

* bpo-23378: Add an extend action to argparser.

* bpo-36867: Fix a bug making a SharedMemoryManager instance and its
  parent process use two separate resource_tracker processes.

* bpo-23896: Adds a grammar to lib2to3.pygram that contains exec as
  a function not as statement.

* bpo-36895: The function "time.clock()" was deprecated in 3.3 in
  favor of "time.perf_counter()" and marked for removal in 3.8, it has
  removed.

* bpo-35545: Fix asyncio discarding IPv6 scopes when ensuring
  hostname resolutions internally

* bpo-36887: Add new function "math.isqrt()" to compute integer
  square roots.

* bpo-34632: Introduce the "importlib.metadata" module with
  (provisional) support for reading metadata from third-party
  packages.

* bpo-36878: When using "type_comments=True" in "ast.parse", treat
  "# type: ignore" followed by a non-alphanumeric character and then
  arbitrary text as a type ignore, instead of requiring nothing but
  whitespace or another comment. This is to permit formations such as
  "# type: ignore[E1000]".

* bpo-36778: "cp65001" encoding (Windows code page 65001) becomes an
  alias to "utf_8" encoding.

* bpo-36867: The multiprocessing.resource_tracker replaces the
  multiprocessing.semaphore_tracker module. Other than semaphores,
  resource_tracker also tracks shared_memory segments.

* bpo-30262: The "Cache" and "Statement" objects of the "sqlite3"
  module are not exposed to the user.  Patch by Aviv Palivoda.

* bpo-24538: In "shutil.copystat()", first copy extended file
  attributes and then file permissions, since extended attributes can
  only be set on the destination while it is still writeable.

* bpo-36829: Add new "sys.unraisablehook()" function which can be
  overridden to control how "unraisable exceptions" are handled. It is
  called when an exception has occurred but there is no way for Python
  to handle it. For example, when a destructor raises an exception or
  during garbage collection ("gc.collect()").

* bpo-36832: Introducing "zipfile.Path", a pathlib-compatible
  wrapper for traversing zip files.

* bpo-36814: Fix an issue where os.posix_spawnp() would incorrectly
  raise a TypeError when file_actions is None.

* bpo-33110: Handle exceptions raised by functions added by
  concurrent.futures add_done_callback correctly when the Future has
  already completed.

* bpo-26903: Limit "max_workers" in "ProcessPoolExecutor" to 61 to
  work around a WaitForMultipleObjects limitation.

* bpo-36813: Fix "QueueListener" to call "queue.task_done()" upon
  stopping. Patch by Bar Harel.

* bpo-36806: Forbid creation of asyncio stream objects like
  StreamReader, StreamWriter, Process, and their protocols outside of
  asyncio package.

* bpo-36802: Provide both sync and async calls for
  StreamWriter.write() and StreamWriter.close()

* bpo-36801: Properly handle SSL connection closing in asyncio
  StreamWriter.drain() call.

* bpo-36785: Implement PEP 574 (pickle protocol 5 with out-of-band
  buffers).

* bpo-36772: functools.lru_cache() can now be used as a straight
  decorator in addition to its existing usage as a function that
  returns a decorator.

* bpo-6584: Add a "BadGzipFile" exception to the "gzip" module.

* bpo-36748: Optimized write buffering in C implementation of
  "TextIOWrapper". Writing ASCII string to "TextIOWrapper" with ascii,
  latin1, or utf-8 encoding is about 20% faster.  Patch by Inada
  Naoki.

* bpo-8138: Don't mark "wsgiref.simple_server.SimpleServer" as
  multi- threaded since "wsgiref.simple_server.WSGIServer" is single-
  threaded.

* bpo-22640: "py_compile.compile()" now supports silent mode. Patch
  by Joannah Nanjekye

* bpo-29183: Fix double exceptions in "wsgiref.handlers.BaseHandler"
  by calling its "close()" method only when no exception is raised.

* bpo-36548: Improved the repr of regular expression flags.

* bpo-36542: The signature of Python functions can now be overridden
  by specifying the "__text_signature__" attribute.

* bpo-36533: Reinitialize logging.Handler locks in forked child
  processes instead of attempting to acquire them all in the parent
  before forking only to be released in the child process.  The
  acquire/release pattern was leading to deadlocks in code that has
  implemented any form of chained logging handlers that depend upon
  one another as the lock acquisition order cannot be guaranteed.

* bpo-35252: Throw a TypeError instead of an AssertionError when
  using an invalid type annotation with singledispatch.

* bpo-35900: Allow reduction methods to return a 6-item tuple where
  the 6th item specifies a custom state-setting method that's called
  instead of the regular "__setstate__" method.

* bpo-35900: enable custom reduction callback registration for
  functions and classes in _pickle.c, using the new Pickler's
  attribute "reducer_override"

* bpo-36368: Fix a bug crashing SharedMemoryManager instances in
  interactive sessions after a ctrl-c (KeyboardInterrupt) was sent

* bpo-31904: Fix mmap fail for VxWorks

* bpo-27497: "csv.DictWriter.writeheader()" now returns the return
  value of the underlying "csv.Writer.writerow()" method. Patch
  contributed by Ashish Nitin Patil.

* bpo-36239: Parsing .mo files now ignores comments starting and
  ending with #-#-#-#-#.

* bpo-26707: Enable plistlib to read and write binary plist files
  that were created as a KeyedArchive file. Specifically, this allows
  the plistlib to process 0x80 tokens as UID objects.

* bpo-31904: Add posix module support for VxWorks.

* bpo-35125: Asyncio: Remove inner callback on outer cancellation in
  shield

* bpo-35721: Fix "asyncio.SelectorEventLoop.subprocess_exec()" leaks
  file descriptors if "Popen" fails and called with
  "stdin=subprocess.PIPE". Patch by Niklas Fiekas.

* bpo-31855: "unittest.mock.mock_open()" results now respects the
  argument of read([size]). Patch contributed by Rémi Lapeyre.

* bpo-35431: Implement "math.comb()" that returns binomial
  coefficient, that computes the number of ways to choose k items from
  n items without repetition and without order. Patch by Yash Aggarwal
  and Keller Fuchs.

* bpo-26660: Fixed permission errors in "TemporaryDirectory" clean
  up. Previously "TemporaryDirectory.cleanup()" failed when non-
  writeable or non-searchable files or directories were created inside
  a temporary directory.

* bpo-34271: Add debugging helpers to ssl module. It's now possible
  to dump key material and to trace TLS protocol. The default and
  stdlib contexts also support SSLKEYLOGFILE env var.

* bpo-26467: Added AsyncMock to support using unittest to mock
  asyncio coroutines. Patch by Lisa Roach.

* bpo-33569: dataclasses.InitVar: Exposes the type used to create
  the init var.

* bpo-34424: Fix serialization of messages containing encoded
  strings when the policy.linesep is set to a multi-character string.
  Patch by Jens Troeger.

* bpo-34303: Performance of "functools.reduce()" is slightly
  improved. Patch by Sergey Fedoseev.

* bpo-33361: Fix a bug in "codecs.StreamRecoder" where seeking might
  leave old data in a buffer and break subsequent read calls. Patch by
  Ammar Askar.

* bpo-22454: The "shlex" module now exposes "shlex.join()", the
  inverse of "shlex.split()". Patch by Bo Bayles.

* bpo-31922: "asyncio.AbstractEventLoop.create_datagram_endpoint()":
  Do not connect UDP socket when broadcast is allowed. This allows to
  receive replies after a UDP broadcast.

* bpo-24882: Change ThreadPoolExecutor to use existing idle threads
  before spinning up new ones.

* bpo-31961: Added support for bytes and path-like objects in
  "subprocess.Popen()" on Windows.  The *args* parameter now accepts a
  *path-like object* if *shell* is "False" and a sequence containing
  bytes and path-like objects. The *executable* parameter now accepts
  a bytes and *path-like object*. The *cwd* parameter now accepts a
  bytes object. Based on patch by Anders Lorentsen.

* bpo-33123: "pathlib.Path.unlink" now accepts a *missing_ok*
  parameter to avoid a "FileNotFoundError" from being raised. Patch by
  Robert Buchholz.

* bpo-32941: Allow "mmap.mmap" objects to access the madvise()
  system call (through "mmap.mmap.madvise()").

* bpo-22102: Added support for ZIP files with disks set to 0. Such
  files are commonly created by builtin tools on Windows when use
  ZIP64 extension. Patch by Francisco Facioni.

* bpo-32515: trace.py can now run modules via python3 -m trace -t
  --module module_name

* bpo-32299: Changed "unittest.mock.patch.dict()" to return the
  patched dictionary when used as context manager. Patch by Vadim
  Tsander.

* bpo-27141: Added a "__copy__()" to "collections.UserList" and
  "collections.UserDict" in order to correctly implement shallow
  copying of the objects. Patch by Bar Harel.

* bpo-31829: "\r", "\0" and "\x1a" (end-of-file on Windows) are now
  escaped in protocol 0 pickles of Unicode strings. This allows to
  load them without loss from files open in text mode in Python 2.

* bpo-23395: "_thread.interrupt_main()" now avoids setting the
  Python error status if the "SIGINT" signal is ignored or not handled
  by Python.


文档
----

* bpo-36896: Clarify that some types have unstable constructor
  signature between Python versions.

* bpo-36686: Improve documentation of the stdin, stdout, and stderr
  arguments of of the "asyncio.subprocess_exec" function to specify
  which values are supported. Also mention that decoding as text is
  not supported.

  Add a few tests to verify that the various values passed to the std*
  arguments actually work.

* bpo-36984: Improve version added references in "typing" module -
  by Anthony Sottile.

* bpo-36868: What's new now mentions
  SSLContext.hostname_checks_common_name instead of
  SSLContext.host_flags.

* bpo-35924: Add a note to the "curses.addstr()" documentation to
  warn that multiline strings can cause segfaults because of an
  ncurses bug.

* bpo-36783: Added C API Documentation for Time_FromTimeAndFold and
  PyDateTime_FromDateAndTimeAndFold as per PEP 495. Patch by Edison
  Abahurire.

* bpo-36797: More of the legacy distutils documentation has been
  either pruned, or else more clearly marked as being retained solely
  until the setuptools documentation covers it independently.

* bpo-22865: Add detail to the documentation on the "pty.spawn"
  function.

* bpo-35397: Remove deprecation and document urllib.parse.unwrap().
  Patch contributed by Rémi Lapeyre.

* bpo-32995: Added the context variable in glossary.

* bpo-33519: Clarify that "copy()" is not part of the
  "MutableSequence" ABC.

* bpo-33482: Make "codecs.StreamRecoder.writelines" take a list of
  bytes.

* bpo-25735: Added documentation for func factorial to indicate that
  returns integer values

* bpo-20285: Expand object.__doc__ (docstring) to make it clearer.
  Modify pydoc.py so that help(object) lists object methods (for other
  classes, help omits methods of the object base class.)


测试
----

* bpo-37069: Modify test_coroutines, test_cprofile, test_generators,
  test_raise, test_ssl and test_yield_from to use
  "test.support.catch_unraisable_exception()" rather than
  "test.support.captured_stderr()".

* bpo-37098: Fix test_memfd_create on older Linux Kernels.

* bpo-37081: Test with OpenSSL 1.1.1c

* bpo-36829: Add "test.support.catch_unraisable_exception()":
  context manager catching unraisable exception using
  "sys.unraisablehook()".

* bpo-36915: The main regrtest process now always removes all
  temporary directories of worker processes even if they crash or if
  they are killed on KeyboardInterrupt (CTRL+c).

* bpo-36719: "python3 -m test -jN ..." now continues the execution
  of next tests when a worker process crash (CHILD_ERROR state).
  Previously, the test suite stopped immediately. Use --failfast to
  stop at the first error.

* bpo-36816: Update Lib/test/selfsigned_pythontestdotnet.pem to
  match self-signed.pythontest.net's new TLS certificate.

* bpo-35925: Skip httplib and nntplib networking tests when they
  would otherwise fail due to a modern OS or distro with a default
  OpenSSL policy of rejecting connections to servers with weak
  certificates.

* bpo-36782: Add tests for several C API functions in the "datetime"
  module. Patch by Edison Abahurire.

* bpo-36342: Fix test_multiprocessing in test_venv if platform lacks
  functioning sem_open.


构建
----

* bpo-36721: To embed Python into an application, a new "--embed"
  option must be passed to "python3-config --libs --embed" to get
  "-lpython3.8" (link the application to libpython). To support both
  3.8 and older, try "python3-config --libs --embed" first and
  fallback to "python3-config --libs" (without "--embed") if the
  previous command fails.

  增加一个 pkg-config "python-3.8-embed" 模块用来将 Python 嵌入到一个
  应用中: "pkg-config python-3.8-embed --libs" 包含 "-lpython3.8"。 要
  同时支持 3.8 和旧版本，请先尝试 "pkg-config python-X.Y-embed --libs"
  并在此命令失败时回退到 "pkg-config python-X.Y --libs" (即不带 "--
  embed") （请将 "X.Y" 替换为 Python 版本号）。

  On the other hand, "pkg-config python3.8 --libs" no longer contains
  "-lpython3.8". C extensions must not be linked to libpython (except
  on Android, case handled by the script); this change is backward
  incompatible on purpose.

* bpo-36786: "make install" now runs compileall in parallel.


Windows
-------

* bpo-36965: include of STATUS_CONTROL_C_EXIT without depending on
  MSC compiler

* bpo-35926: Update to OpenSSL 1.1.1b for Windows.

* bpo-29883: Add Windows support for UDP transports for the Proactor
  Event Loop. Patch by Adam Meily.

* bpo-33407: The "Py_DEPRECATED()" macro has been implemented for
  MSVC.


macOS
-----

* bpo-36231: Support building Python on macOS without /usr/include
  installed. As of macOS 10.14, system header files are only available
  within an SDK provided by either the Command Line Tools or the Xcode
  app.


IDLE
----

* bpo-35610: Replace now redundant .context_use_ps1 with
  .prompt_last_line. This finishes change started in bpo-31858.

* bpo-37038: Make idlelib.run runnable; add test clause.

* bpo-36958: Print any argument other than None or int passed to
  SystemExit or sys.exit().

* bpo-36807: When saving a file, call os.fsync() so bits are flushed
  to e.g. USB drive.

* bpo-32411: In browser.py, remove extraneous sorting by line number
  since dictionary was created in line number order.


工具/示例
---------

* bpo-37053: Handle strings like u"bar" correctly in
  Tools/parser/unparse.py. Patch by Chih-Hsuan Yen.


C API
-----

* bpo-36763: Implement the **PEP 587** "Python Initialization
  Configuration".

* bpo-36379: Fix crashes when attempting to use the *modulo*
  parameter when "__ipow__" is implemented in C.

* bpo-37107: Update "PyObject_CallMethodObjArgs()" and
  "_PyObject_CallMethodIdObjArgs" to use "_PyObject_GetMethod" to
  avoid creating a bound method object in many cases. Patch by Michael
  J. Sullivan.

* bpo-36974: Implement **PEP 590**: Vectorcall: a fast calling
  protocol for CPython. This is a new protocol to optimize calls of
  custom callable objects.

* bpo-36763: "Py_Main()" now returns the exitcode rather than
  calling "Py_Exit(exitcode)" when calling "PyErr_Print()" if the
  current exception type is "SystemExit".

* bpo-36922: Add new type flag "Py_TPFLAGS_METHOD_DESCRIPTOR" for
  objects behaving like unbound methods. These are objects supporting
  the optimization given by the "LOAD_METHOD"/"CALL_METHOD" opcodes.
  See PEP 590.

* bpo-36728: The "PyEval_ReInitThreads()" function has been removed
  from the C API. It should not be called explicitly: use
  "PyOS_AfterFork_Child()" instead.


Python 3.8.0 alpha 4
====================

*Release date: 2019-05-06*


安全
----

* bpo-36742: 于函数 urlsplit() 中修复了对于预规格化字符的不当处理过
  程 。

* bpo-30458: Address CVE-2019-9740 by disallowing URL paths with
  embedded whitespace or control characters through into the
  underlying http client request.  Such potentially malicious header
  injection URLs now cause an http.client.InvalidURL exception to be
  raised.

* bpo-35755: "shutil.which()" now uses "os.confstr("CS_PATH")" if
  available and if the "PATH" environment variable is not set. Remove
  also the current directory from "posixpath.defpath". On Unix,
  "shutil.which()" and the "subprocess" module no longer search the
  executable in the current directory if the "PATH" environment
  variable is not set.


核心与内置
----------

* bpo-36722: In debug build, import now also looks for C extensions
  compiled in release mode and for C extensions compiled in the stable
  ABI.

* bpo-32849: Fix Python Initialization code on FreeBSD to detect
  properly when stdin file descriptor (fd 0) is invalid.

* bpo-36623: Remove parser headers and related function declarations
  that lack implementations after the removal of pgen.

* bpo-20180: "dict.pop()" is now up to 33% faster thanks to Argument
  Clinic. Patch by Inada Naoki.

* bpo-36611: Debug memory allocators: disable serialno field by
  default from debug hooks on Python memory allocators to reduce the
  memory footprint by 5%. Enable "tracemalloc" to get the traceback
  where a memory block has been allocated when a fatal memory error is
  logged to decide where to put a breakpoint. Compile Python with
  "PYMEM_DEBUG_SERIALNO" defined to get back the field.

* bpo-36588: On AIX, "sys.platform" doesn't contain the major
  version anymore. Always return "'aix'", instead of "'aix3'" ..
  "'aix7'". Since older Python versions include the version number, it
  is recommended to always use "sys.platform.startswith('aix')".
  Contributed by M. Felt.

* bpo-36549: Change str.capitalize to use titlecase for the first
  character instead of uppercase.

* bpo-36540: Implement **PEP 570** (Python positional-only
  parameters). Patch by Pablo Galindo.

* bpo-36475: "PyEval_AcquireLock()" and "PyEval_AcquireThread()" now
  terminate the current thread if called while the interpreter is
  finalizing, making them consistent with "PyEval_RestoreThread()",
  "Py_END_ALLOW_THREADS()", and "PyGILState_Ensure()".

* bpo-36504: 在 _ctypes.c's "PyCArrayType_new()" 中修复了“有符号整数
  ” 类型的溢出。

* bpo-20844: 修复了含有经编码的 cookie 和换行符的脚本位于 Windows 平
  台 可能运行失败的问题。

* bpo-24214: 修复了UTF-8增量解码器对surrogatepass的错误回调方法的支
  持

* bpo-36452: Changing "dict" keys during iteration of the dict
  itself, "keys()", "values()", or "items()" will now be detected in
  certain corner cases where keys are deleted/added so that the number
  of keys isn't changed. A "RuntimeError" will be raised after
  "len(dict)" iterations. Contributed by Thomas Perl.

* bpo-36459: 修复了由于tokenizer.c中的 "tok_nextc()" 方法可能导致的
  两 次 "PyMem_FREE()" 调用。

* bpo-36433: 修复了位于 classmethoddescr_call 的类型错误信息

* bpo-36430: 修复了函数 "itertools.count()" 中的潜在引用对象泄漏。

* bpo-36440: Include node names in "ParserError" messages, instead
  of numeric IDs. Patch by A. Skrobov.

* bpo-36143: Regenerate "keyword" from the Grammar and Tokens file
  using pgen. Patch by Pablo Galindo.

* bpo-18372: Add missing "PyObject_GC_Track()" calls in the "pickle"
  module. Patch by Zackery Spytz.


库
--

* bpo-35952: Fix pythoninfo when the compiler is missing.

* bpo-28238: The ".find*()" methods of xml.etree.ElementTree can now
  search for wildcards like "{*}tag" and "{ns}*" that match a tag in
  any namespace or all tags in a namespace.  Patch by Stefan Behnel.

* bpo-26978: "pathlib.path.link_to()" is now implemented. It creates
  a hard link pointing to a path.

* bpo-1613500: "fileinput.FileInput" now uses the input file mode to
  correctly set the output file mode (previously it was hardcoded to
  "'w'")  when "inplace=True" is passed to its constructor.

* bpo-36734: Fix compilation of "faulthandler.c" on HP-UX.
  Initialize "stack_t current_stack" to zero using "memset()".

* bpo-13611: The xml.etree.ElementTree packages gained support for
  C14N 2.0 serialisation. Patch by Stefan Behnel.

* bpo-36669: Add missing matrix multiplication operator support to
  weakref.proxy.

* bpo-36676: The XMLParser() in xml.etree.ElementTree provides
  namespace prefix context to the parser target if it defines the
  callback methods "start_ns()" and/or "end_ns()". Patch by Stefan
  Behnel.

* bpo-36673: The TreeBuilder and XMLPullParser in
  xml.etree.ElementTree gained support for parsing comments and
  processing instructions. Patch by Stefan Behnel.

* bpo-36650: The C version of functools.lru_cache() was treating
  calls with an empty "**kwargs" dictionary as being distinct from
  calls with no keywords at all. This did not result in an incorrect
  answer, but it did trigger an unexpected cache miss.

* bpo-28552: Fix "distutils.sysconfig" if "sys.executable" is "None"
  or an empty string: use "os.getcwd()" to initialize "project_base".
  Fix also the distutils build command: don't use "sys.executable" if
  it is "None" or an empty string.

* bpo-35755: "shutil.which()" and
  "distutils.spawn.find_executable()" now use "os.confstr("CS_PATH")"
  if available instead of "os.defpath", if the "PATH" environment
  variable is not set. Moreover, don't use "os.confstr("CS_PATH")" nor
  "os.defpath" if the "PATH" environment variable is set to an empty
  string.

* bpo-25430: improve performance of "IPNetwork.__contains__()"

* bpo-30485: Path expressions in xml.etree.ElementTree can now avoid
  explicit namespace prefixes for tags (or the "{namespace}tag"
  notation) by passing a default namespace with an empty string
  prefix.

* bpo-36613: Fix "asyncio" wait() not removing callback if exception

* bpo-36598: Fix "isinstance" check for Mock objects with spec when
  the code is executed under tracing. Patch by Karthikeyan
  Singaravelan.

* bpo-18748: In development mode ("-X" "dev") and in debug build,
  the "io.IOBase" destructor now logs "close()" exceptions. These
  exceptions are silent by default in release mode.

* bpo-36575: The "_lsprof" module now uses internal timer same to
  "time.perf_counter()" by default. "gettimeofday(2)" was used on
  Unix. New timer has better resolution on most Unix platforms and
  timings are no longer impacted by system clock updates since
  "perf_counter()" is monotonic. Patch by Inada Naoki.

* bpo-33461: "json.loads" now emits "DeprecationWarning" when
  "encoding" option is specified.  Patch by Matthias Bussonnier.

* bpo-36559: The random module now prefers the lean internal _sha512
  module over hashlib for seed(version=2) to optimize import time.

* bpo-17561: Set backlog=None as the default for
  socket.create_server.

* bpo-34373: Fix "time.mktime()" error handling on AIX for year
  before 1970.

* bpo-36232: Improve error message when trying to open existing DBM
  database that actually doesn't exist. Patch by Marco Rougeth.

* bpo-36546: Add statistics.quantiles()

* bpo-36050: Optimized "http.client.HTTPResponse.read()" for large
  response. Patch by Inada Naoki.

* bpo-36522: If *debuglevel* is set to >0 in "http.client", print
  all values for headers with multiple values for the same header
  name. Patch by Matt Houglum.

* bpo-36492: Deprecated passing required arguments like *func* as
  keyword arguments in functions which should accept arbitrary keyword
  arguments and pass them to other function. Arbitrary keyword
  arguments (even with names "self" and "func") can now be passed to
  these functions if the required arguments are passed as positional
  arguments.

* bpo-27181: Add statistics.geometric_mean().

* bpo-30427: "os.path.normcase()" relies on "os.fspath()" to check
  the type of its argument. Redundant checks have been removed from
  its "posixpath.normcase()" and "ntpath.normcase()" implementations.
  Patch by Wolfgang Maier.

* bpo-36385: Stop rejecting IPv4 octets for being ambiguously octal.
  Leading zeros are ignored, and no longer are assumed to specify
  octal octets. Octets are always decimal numbers. Octets must still
  be no more than three digits, including leading zeroes.

* bpo-36434: Errors during writing to a ZIP file no longer prevent
  to properly close it.

* bpo-36407: Fixed wrong indentation writing for CDATA section in
  xml.dom.minidom. Patch by Vladimir Surjaninov.

* bpo-36326: inspect.getdoc() can now find docstrings for member
  objects when __slots__ is a dictionary.

* bpo-36366: Calling "stop()" on an unstarted or stopped
  "unittest.mock.patch()" object will now return "None" instead of
  raising "RuntimeError", making the method idempotent. Patch by
  Karthikeyan Singaravelan.

* bpo-36348: The "imap.IMAP4.logout()" method no longer ignores
  silently arbitrary exceptions.

* bpo-31904: Add time module support and fix test_time faiures for
  VxWorks.

* bpo-36227: Added support for keyword arguments "default_namespace"
  and "xml_declaration" in functions ElementTree.tostring() and
  ElementTree.tostringlist().

* bpo-36004: Added new alternate constructors
  "datetime.date.fromisocalendar()" and
  "datetime.datetime.fromisocalendar()", which construct date objects
  from ISO year, week number and weekday; these are the inverse of
  each class's "isocalendar" method. Patch by Paul Ganssle.

* bpo-35936: "modulefinder" no longer depends on the deprecated
  "imp" module, and the initializer for "modulefinder.ModuleFinder"
  now has immutable default arguments. Patch by Brandt Bucher.

* bpo-35376: "modulefinder" correctly handles modules that have the
  same name as a bad package. Patch by Brandt Bucher.

* bpo-17396: "modulefinder" no longer crashes when encountering
  syntax errors in followed imports. Patch by Brandt Bucher.

* bpo-35934: Added "create_server()" and "has_dualstack_ipv6()"
  convenience functions to automate the necessary tasks usually
  involved when creating a server socket, including accepting both
  IPv4 and IPv6 connections on the same socket.  (Contributed by
  Giampaolo Rodola in bpo-17561.)

* bpo-23078: Add support for "classmethod()" and "staticmethod()" to
  "unittest.mock.create_autospec()".  Initial patch by Felipe Ochoa.

* bpo-35416: Fix potential resource warnings in distutils. Patch by
  Mickaël Schoentgen.

* bpo-25451: Add transparency methods to "tkinter.PhotoImage".
  Patch by Zackery Spytz.

* bpo-35082: Don't return deleted attributes when calling dir on a
  "unittest.mock.Mock".

* bpo-34547: "wsgiref.handlers.BaseHandler" now handles abrupt
  client connection terminations gracefully. Patch by Petter
  Strandmark.

* bpo-31658: "xml.sax.parse()" now supports *path-like*. Patch by
  Mickaël Schoentgen.

* bpo-34139: Remove stale unix datagram socket before binding

* bpo-33530: Implemented Happy Eyeballs in
  "asyncio.create_connection()". Added two new arguments,
  *happy_eyeballs_delay* and *interleave*, to specify Happy Eyeballs
  behavior.

* bpo-33291: Do not raise AttributeError when calling the inspect
  functions isgeneratorfunction, iscoroutinefunction,
  isasyncgenfunction on a method created from an arbitrary callable.
  Instead, return False.

* bpo-31310: Fix the multiprocessing.semaphore_tracker so it is
  reused by child processes

* bpo-31292: 为包含 "include" 指令的文件修复 "setup.py check
  --restructuredtext"。


文档
----

* bpo-36625: Remove obsolete comments from docstrings in
  fractions.Fraction

* bpo-30840: Document relative imports

* bpo-36523: Add docstring for io.IOBase.writelines().

* bpo-36425: 新增的文档翻译: 简体中文.

* bpo-36345: Avoid the duplication of code from
  "Tools/scripts/serve.py" in using the "literalinclude" directive for
  the basic wsgiref-based web server in the documentation of
  "wsgiref". Contributed by Stéphane Wirtel.

* bpo-36345: Using the code of the "Tools/scripts/serve.py" script
  as an example in the "wsgiref" documentation.  Contributed by
  Stéphane Wirtel.

* bpo-36157: Added Documention for  PyInterpreterState_Main().

* bpo-33043: Updates the docs.python.org page with the addition of a
  'Contributing to Docs' link at the end of the page (between
  'Reporting Bugs' and 'About Documentation'). Updates the 'Found a
  Bug' page with additional links and information in the Documentation
  Bugs section.

* bpo-35581: @typing.type_check_only now allows type stubs to mark
  functions and classes not available during runtime.

* bpo-33832: Add glossary entry for 'magic method'.

* bpo-32913: Added re.Match.groupdict example to regex HOWTO.


测试
----

* bpo-36719: regrtest now always detects uncollectable objects.
  Previously, the check was only enabled by "--findleaks". The check
  now also works with "-jN/--multiprocess N". "--findleaks" becomes a
  deprecated alias to "--fail-env-changed".

* bpo-36725: When using mulitprocessing mode (-jN), regrtest now
  better reports errors if a worker process fails, and it exits
  immediately on a worker thread failure or when interrupted.

* bpo-36454: Change test_time.test_monotonic() to test only the
  lower bound of elapsed time after a sleep command rather than the
  upper bound. This prevents unnecessary test failures on slow
  buildbots. Patch by Victor Stinner.

* bpo-32424: Improve test coverage for xml.etree.ElementTree. Patch
  by Gordon P. Hemsley.

* bpo-32424: Fix typo in test_cyclic_gc() test for
  xml.etree.ElementTree. Patch by Gordon P. Hemsley.

* bpo-36635: Add a new "_testinternalcapi" module to test the
  internal C API.

* bpo-36629: Fix "test_imap4_host_default_value()" of
  "test_imaplib": catch also "errno.ENETUNREACH" error.

* bpo-36611: Fix "test_sys.test_getallocatedblocks()" when
  "tracemalloc" is enabled.

* bpo-36560: Fix reference leak hunting in regrtest: compute also
  deltas (of reference count, allocated memory blocks, file descriptor
  count) during warmup, to ensure that everything is initialized
  before starting to hunt reference leaks.

* bpo-36565: Fix reference hunting ("python3 -m test -R 3:3") when
  Python has no built-in abc module.

* bpo-31904: Port test_resource to VxWorks: skip tests cases setting
  RLIMIT_FSIZE and RLIMIT_CPU.

* bpo-31904: Fix test_tabnanny on VxWorks: adjust ENOENT error
  message.

* bpo-36436: Fix "_testcapi.pymem_buffer_overflow()": handle memory
  allocation failure.

* bpo-31904: Fix test_utf8_mode on VxWorks: Python always use UTF-8
  on VxWorks.

* bpo-36341: Fix tests that may fail with PermissionError upon
  calling bind() on AF_UNIX sockets.


构建
----

* bpo-36747: Remove the stale scriptsinstall Makefile target.

* bpo-21536: On Unix, C extensions are no longer linked to libpython
  except on Android and Cygwin.

  It is now possible for a statically linked Python to load a C
  extension built using a shared library Python.

  When Python is embedded, "libpython" must not be loaded with
  "RTLD_LOCAL", but "RTLD_GLOBAL" instead. Previously, using
  "RTLD_LOCAL", it was already not possible to load C extensions which
  were not linked to "libpython", such as C extensions of the standard
  library built by the "*shared*" section of "Modules/Setup".

  distutils, python-config and python-config.py have been modified.

* bpo-36707: "./configure --with-pymalloc" no longer adds the "m"
  flag to SOABI (sys.implementation.cache_tag). Enabling or disabling
  pymalloc has no impact on the ABI.

* bpo-36635: Change "PyAPI_FUNC(type)", "PyAPI_DATA(type)" and
  "PyMODINIT_FUNC" macros of "pyport.h" when "Py_BUILD_CORE_MODULE" is
  defined. The "Py_BUILD_CORE_MODULE" define must be now be used to
  build a C extension as a dynamic library accessing Python internals:
  export the PyInit_xxx() function in DLL exports on Windows.

* bpo-31904: Don't build the "_crypt" extension on VxWorks.

* bpo-36618: Add "-fmax-type-align=8" to CFLAGS when clang compiler
  is detected. The pymalloc memory allocator aligns memory on 8 bytes.
  On x86-64, clang expects alignment on 16 bytes by default and so
  uses MOVAPS instruction which can lead to segmentation fault.
  Instruct clang that Python is limited to alignment on 8 bytes to use
  MOVUPS instruction instead: slower but don't trigger a SIGSEGV if
  the memory is not aligned on 16 bytes. Sadly, the flag must be added
  to "CFLAGS" and not just "CFLAGS_NODIST", since third party C
  extensions can have the same issue.

* bpo-36605: "make tags" and "make TAGS" now also parse
  "Modules/_io/*.c" and "Modules/_io/*.h".

* bpo-36465: Release builds and debug builds are now ABI compatible:
  defining the "Py_DEBUG" macro no longer implies the "Py_TRACE_REFS"
  macro, which introduces the only ABI incompatibility. The
  "Py_TRACE_REFS" macro, which adds the "sys.getobjects()" function
  and the "PYTHONDUMPREFS" environment variable, can be set using the
  new "./configure --with-trace-refs" build option.

* bpo-36577: setup.py now correctly reports missing OpenSSL headers
  and libraries again.

* bpo-36544: Fix regression introduced in bpo-36146 refactoring
  setup.py

* bpo-36508: "python-config --ldflags" no longer includes flags of
  the "LINKFORSHARED" variable. The "LINKFORSHARED" variable must only
  be used to build executables.

* bpo-36503: Remove references to "aix3" and "aix4". Patch by M.
  Felt.


Windows
-------

* bpo-35920: Added platform.win32_edition() and
  platform.win32_is_iot(). Added support for cross-compiling packages
  for Windows ARM32. Skip tests that are not expected to work on
  Windows IoT Core ARM32.

* bpo-36649: Remove trailing spaces for registry keys when installed
  via the Store.

* bpo-34144: Fixed activate.bat to correctly update codepage when
  chcp.com returns dots in output. Patch by Lorenz Mende.

* bpo-36509: Added preset-iot layout for Windows IoT ARM containers.
  This layout doesn't contain UI components like tkinter or IDLE. It
  also doesn't contain files to support on-target builds since Windows
  ARM32 builds must be cross-compiled when using MSVC.

* bpo-35941: enum_certificates function of the ssl module now
  returns certificates from all available certificate stores inside
  windows in a query instead of returning only certificates from the
  system wide certificate store. This includes certificates from these
  certificate stores: local machine, local machine enterprise, local
  machine group policy, current user, current user group policy,
  services, users. ssl.enum_crls() function is changed in the same way
  to return all certificate revocation lists inside the windows
  certificate revocation list stores.

* bpo-36441: Fixes creating a venv when debug binaries are
  installed.

* bpo-36085: Enable better DLL resolution on Windows by using safe
  DLL search paths and adding "os.add_dll_directory()".

* bpo-36010: Add the venv standard library module to the nuget
  distribution for Windows.

* bpo-29515: Add the following socket module constants on Windows:
  IPPROTO_AH IPPROTO_CBT IPPROTO_DSTOPTS IPPROTO_EGP IPPROTO_ESP
  IPPROTO_FRAGMENT IPPROTO_GGP IPPROTO_HOPOPTS IPPROTO_ICLFXBM
  IPPROTO_ICMPV6 IPPROTO_IDP IPPROTO_IGMP IPPROTO_IGP IPPROTO_IPV4
  IPPROTO_IPV6 IPPROTO_L2TP IPPROTO_MAX IPPROTO_ND IPPROTO_NONE
  IPPROTO_PGM IPPROTO_PIM IPPROTO_PUP IPPROTO_RDP IPPROTO_ROUTING
  IPPROTO_SCTP IPPROTO_ST

* bpo-35947: Added current version of libffi to cpython-source-deps.
  Change _ctypes to use current version of libffi on Windows.

* bpo-34060: Report system load when running test suite on Windows.
  Patch by Ammar Askar. Based on prior work by Jeremy Kloth.

* bpo-31512: With the Windows 10 Creators Update, non-elevated users
  can now create symlinks as long as the computer has Developer Mode
  enabled.


macOS
-----

* bpo-34602: Avoid failures setting macOS stack resource limit with
  resource.setrlimit. This reverts an earlier fix for bpo-18075 which
  forced a non-default stack size when building the interpreter
  executable on macOS.


IDLE
----

* bpo-36429: Fix starting IDLE with pyshell. Add idlelib.pyshell
  alias at top; remove pyshell alias at bottom. Remove obsolete
  __name__=='__main__' command.


工具/示例
---------

* bpo-14546: Fix the argument handling in Tools/scripts/lll.py.


C API
-----

* bpo-36763: Fix memory leak in "Py_SetStandardStreamEncoding()":
  release memory if the function is called twice.

* bpo-36641: "PyDoc_VAR(name)" and "PyDoc_STRVAR(name,str)" now
  create "static const char name[]" instead of "static char name[]".
  Patch by Inada Naoki.

* bpo-36389: Change the value of "CLEANBYTE", "DEADDYTE" and
  "FORBIDDENBYTE" internal constants used by debug hooks on Python
  memory allocators ("PyMem_SetupDebugHooks()" function). Byte
  patterns "0xCB", "0xDB" and "0xFB" have been replaced with "0xCD",
  "0xDD" and "0xFD" to use the same values than Windows CRT debug
  "malloc()" and "free()".

* bpo-36443: Since Python 3.7.0, calling "Py_DecodeLocale()" before
  "Py_Initialize()" produces mojibake if the "LC_CTYPE" locale is
  coerced and/or if the UTF-8 Mode is enabled by the user
  configuration. The LC_CTYPE coercion and UTF-8 Mode are now disabled
  by default to fix the mojibake issue. They must now be enabled
  explicitly (opt-in) using the new "_Py_PreInitialize()" API with
  "_PyPreConfig".

* bpo-36025: Fixed an accidental change to the datetime C API where
  the arguments to the "PyDate_FromTimestamp()" function were
  incorrectly interpreted as a single timestamp rather than an
  arguments tuple, which causes existing code to start raising
  "TypeError". The backwards-incompatible change was only present in
  alpha releases of Python 3.8. Patch by Paul Ganssle.

* bpo-35810: Modify "PyObject_Init" to correctly increase the
  refcount of heap- allocated Type objects. Also fix the refcounts of
  the heap- allocated types that were either doing this manually or
  not decreasing the type's refcount in tp_dealloc


Python 3.8.0 alpha 3
====================

*发布日期： 2019-03-25*


安全
----

* bpo-36216: Changes urlsplit() to raise ValueError when the URL
  contains characters that decompose under IDNA encoding (NFKC-
  normalization) into characters that affect how the URL is parsed.

* bpo-35121: Don't send cookies of domain A without Domain attribute
  to domain B when domain A is a suffix match of domain B while using
  a cookiejar with "http.cookiejar.DefaultCookiePolicy" policy. Patch
  by Karthikeyan Singaravelan.


核心与内置
----------

* bpo-36421: Fix a possible double decref in _ctypes.c's
  "PyCArrayType_new()".

* bpo-36412: Fix a possible crash when creating a new dictionary.

* bpo-36398: Fix a possible crash in "structseq_repr()".

* bpo-36256: Fix bug in parsermodule when parsing a state in a DFA
  that has two or more arcs with labels of the same type. Patch by
  Pablo Galindo.

* bpo-36365: repr(structseq) is no longer limited to 512 bytes.

* bpo-36374: Fix a possible null pointer dereference in
  "merge_consts_recursive()". Patch by Zackery Spytz.

* bpo-36236: 在 Python 初始化时，如果当前目录被移除，则它将不再会被
  添 加到 "sys.path" 中。

* bpo-36352: Python initialization now fails with an error, rather
  than silently truncating paths, if a path is too long.

* bpo-36301: Python initialization now fails if decoding
  "pybuilddir.txt" configuration file fails at startup.

* bpo-36333: Fix leak in _PyRuntimeState_Fini. Contributed by
  Stéphane Wirtel.

* bpo-36332: The builtin "compile()" can now handle AST objects that
  contain assignment expressions. Patch by Pablo Galindo.

* bpo-36282: Improved error message for too much positional
  arguments in some builtin functions.

* bpo-30040: New empty dict uses fewer memory for now.  It used more
  memory than empty dict created by "dict.clear()".  And empty dict
  creation and deletion is about 2x faster.  Patch by Inada Naoki.

* bpo-36262: 修复了在 "float(str)", "complex(str)", "pickle.load()",
  "marshal.load()" 等所用的函数 "_Py_dg_strtod()" 中进行从字符串到浮点
  数的转换时偶有发生的一个内存泄漏问题。

* bpo-36252: Update Unicode databases to version 12.0.0.

* bpo-36218: Fix a segfault occurring when sorting a list of
  heterogeneous values. Patch contributed by Rémi Lapeyre and Elliot
  Gorokhovsky.

* bpo-36188: Cleaned up left-over vestiges of Python 2 unbound
  method handling in method objects and documentation. Patch by
  Martijn Pieters

* bpo-36124: Add a new interpreter-specific dict and expose it in
  the C-API via PyInterpreterState_GetDict().  This parallels
  PyThreadState_GetDict(). However, extension modules should continue
  using PyModule_GetState() for their own internal per-interpreter
  state.

* bpo-35975: Add a "feature_version" flag to "ast.parse()"
  (documented) and "compile()" (hidden) that allows tweaking the
  parser to support older versions of the grammar. In particular, if
  "feature_version" is 5 or 6, the hacks for the "async" and "await"
  keyword from PEP 492 are reinstated. (For 7 or higher, these are
  unconditionally treated as keywords, but they are still special
  tokens rather than "NAME" tokens that the parser driver recognizes.)

* bpo-31904: Use UTF-8 as the system encoding on VxWorks.

* bpo-36048: The "__index__()" special method will be used instead
  of "__int__()" for implicit conversion of Python numbers to C
  integers. Using the "__int__()" method in implicit conversions has
  been deprecated.

* bpo-35808: Retire pgen and use a modified version of pgen2 to
  generate the parser. Patch by Pablo Galindo.


库
--

* bpo-36401: The class documentation created by pydoc now has a
  separate section for readonly properties.

* bpo-36320: The typing.NamedTuple() class has deprecated the
  _field_types attribute in favor of the __annotations__ attribute
  which carried the same information. Also, both attributes were
  converted from OrderedDict to a regular dict.

* bpo-34745: Fix "asyncio" ssl memory issues caused by circular
  references

* bpo-36324: Add method to statistics.NormalDist for computing the
  inverse cumulative normal distribution.

* bpo-36321: collections.namedtuple() misspelled the name of an
  attribute. To be consistent with typing.NamedTuple, the attribute
  name should have been "_field_defaults" instead of
  "_fields_defaults".  For backwards compatibility, both spellings are
  now created.  The misspelled version may be removed in the future.

* bpo-36297: "unicode_internal" codec is removed.  It was deprecated
  since Python 3.3. Patch by Inada Naoki.

* bpo-36298: Raise ModuleNotFoundError in pyclbr when a module can't
  be found. Thanks to 'mental' for the bug report.

* bpo-36268: Switch the default format used for writing tars with
  mod:"tarfile" to the modern POSIX.1-2001 pax standard, from the
  vendor-specific GNU. Contributed by C.A.M. Gerlach.

* bpo-36285: Fix integer overflows in the array module. Patch by
  Stephan Hohe.

* bpo-31904: Add _signal module support for VxWorks.

* bpo-36272: "logging" does not silently ignore RecursionError
  anymore. Patch contributed by Rémi Lapeyre.

* bpo-36280: Add a kind field to ast.Constant. It is 'u' if the
  literal has a 'u' prefix (i.e. a Python 2 style unicode literal),
  else None.

* bpo-35931: The "pdb" "debug" command now gracefully handles all
  exceptions.

* bpo-36251: Fix format strings used for stderrprinter and re.Match
  reprs. Patch by Stephan Hohe.

* bpo-36235: Fix "CFLAGS" in "customize_compiler()" of
  "distutils.sysconfig": when the "CFLAGS" environment variable is
  defined, don't override "CFLAGS" variable with the "OPT" variable
  anymore. Initial patch written by David Malcolm.

* bpo-35807: Update ensurepip to install pip 19.0.3 and setuptools
  40.8.0.

* bpo-36139: Release GIL when closing "mmap" objects.

* bpo-36179: Fix two unlikely reference leaks in _hashopenssl. The
  leaks only occur in out-of-memory cases.

* bpo-36169: Add overlap() method to statistics.NormalDist.
  Computes the overlapping coefficient for two normal distributions.

* bpo-36103: Default buffer size used by "shutil.copyfileobj()" is
  changed from 16 KiB to 64 KiB on non-Windows platform to reduce
  system call overhead. Contributed by Inada Naoki.

* bpo-36130: Fix "pdb" with "skip=..." when stepping into a frame
  without a "__name__" global.  Patch by Anthony Sottile.

* bpo-35652: shutil.copytree(copy_function=...) erroneously pass
  DirEntry instead of a path string.

* bpo-35178: Ensure custom "warnings.formatwarning()" function can
  receive "line" as positional argument. Based on patch by Tashrif
  Billah.

* bpo-36106: Resolve potential name clash with libm's sinpi(). Patch
  by Dmitrii Pasechnik.

* bpo-36091: Clean up reference to async generator in Lib/types.
  Patch by Henry Chen.

* bpo-36043: "FileCookieJar" supports *path-like object*.
  Contributed by Stéphane Wirtel

* bpo-35899: Enum has been fixed to correctly handle empty strings
  and strings with non-Latin characters (ie. 'α', 'א') without
  crashing. Original patch contributed by Maxwell. Assisted by
  Stéphane Wirtel.

* bpo-21269: Add "args" and "kwargs" properties to mock call
  objects. Contributed by Kumar Akshay.

* bpo-30670: "pprint.pp" has been added to pretty-print objects with
  dictionary keys being sorted with their insertion order by default.
  Parameter *sort_dicts* has been added to "pprint.pprint",
  "pprint.pformat" and "pprint.PrettyPrinter". Contributed by Rémi
  Lapeyre.

* bpo-35843: Implement "__getitem__" for "_NamespacePath".  Patch by
  Anthony Sottile.

* bpo-35802: Clean up code which checked presence of "os.stat" /
  "os.lstat" / "os.chmod" which are always present.  Patch by Anthony
  Sottile.

* bpo-35715: Librates the return value of a ProcessPoolExecutor
  _process_worker after it's no longer needed to free memory

* bpo-35493: Use "multiprocessing.connection.wait()" instead of
  polling each 0.2 seconds for worker updates in
  "multiprocessing.Pool". Patch by Pablo Galindo.

* bpo-35661: Store the venv prompt in pyvenv.cfg.

* bpo-35121: Don't set cookie for a request when the request path is
  a prefix match of the cookie's path attribute but doesn't end with
  "/". Patch by Karthikeyan Singaravelan.

* bpo-21478: Calls to a child function created with
  "unittest.mock.create_autospec()" should propagate to the parent.
  Patch by Karthikeyan Singaravelan.

* bpo-35198: Fix C++ extension compilation on AIX


文档
----

* bpo-36329: Declare the path of the Python binary for the usage of
  "Tools/scripts/serve.py" when executing "make -C Doc/ serve".
  Contributed by Stéphane Wirtel

* bpo-36138: Improve documentation about converting
  datetime.timedelta to scalars.

* bpo-21314: A new entry was added to the Core Language Section of
  the Programming FAQ, which explaines the usage of slash(/) in the
  signature of a function. Patch by Lysandros Nikolaou


测试
----

* bpo-36234: test_posix.PosixUidGidTests: add tests for invalid
  uid/gid type (str). Initial patch written by David Malcolm.

* bpo-29571: Fix "test_re.test_locale_flag()":  use
  "locale.getpreferredencoding()" rather than "locale.getlocale()" to
  get the locale encoding. With some locales, "locale.getlocale()"
  returns the wrong encoding.

* bpo-36123: Fix race condition in test_socket.


构建
----

* bpo-36356: Fix leaks that led to build failure when configured
  with address sanitizer.

* bpo-36146: Add "TEST_EXTENSIONS" constant to "setup.py" to allow
  to not build test extensions like "_testcapi".

* bpo-36146: Fix setup.py on macOS: only add "/usr/include/ffi" to
  include directories of _ctypes, not for all extensions.

* bpo-31904: Enable build system to cross-build for VxWorks RTOS.


Windows
-------

* bpo-36312: Fixed decoders for the following code pages: 50220,
  50221, 50222, 50225, 50227, 50229, 57002 through 57011, 65000 and
  42.

* bpo-36264: Don't honor POSIX "HOME" in "os.path.expanduser" on
  windows.  Patch by Anthony Sottile.

* bpo-24643: Fix name collisions due to "#define timezone _timezone"
  in PC/pyconfig.h.


IDLE
----

* bpo-36405: Use dict unpacking in idlelib.

* bpo-36396: Remove fgBg param of idlelib.config.GetHighlight().
  This param was only used twice and changed the return type.

* bpo-36176: 修复 IDLE 自动补全和 calltip 悬浮窗的颜色. 避免与 Linux
  暗色主题冲突 (略微加深了calltip 的背景颜色).

* bpo-23205: For the grep module, add tests for findfiles, refactor
  findfiles to be a module-level function, and refactor findfiles to
  use os.walk.

* bpo-23216: Add docstrings to IDLE search modules.

* bpo-36152: Remove colorizer.ColorDelegator.close_when_done and the
  corresponding argument of .close().  In IDLE, both have always been
  None or False since 2007.

* bpo-32129: Avoid blurry IDLE application icon on macOS with Tk
  8.6. Patch by Kevin Walzer.

* bpo-36096: Refactor class variables to instance variables in
  colorizer.

* bpo-30348: Increase test coverage of idlelib.autocomplete by 30%.
  Patch by Louie Lu


工具/示例
---------

* bpo-35132: Fix py-list and py-bt commands of python-gdb.py on
  gdb7.

* bpo-32217: Fix freeze script on Windows.


C API
-----

* bpo-36381: Raise "DeprecationWarning" when '#' formats are used
  for building or parsing values without "PY_SSIZE_T_CLEAN".

* bpo-36142: The whole coreconfig.h header is now excluded from
  Py_LIMITED_API. Move functions definitions into a new internal
  pycore_coreconfig.h header.


Python 3.8.0 alpha 2
====================

*Release date: 2019-02-25*


核心与内置
----------

* bpo-36052: Raise a "SyntaxError" when assigning a value to
  "__debug__" with the Assignment Operator. Contributed by Stéphane
  Wirtel and Pablo Galindo.

* bpo-36012: Doubled the speed of class variable writes.  When a
  non- dunder attribute was updated, there was an unnecessary call to
  update slots.

* bpo-35942: The error message emitted when returning invalid types
  from "__fspath__" in interfaces that allow passing "PathLike"
  objects has been improved and now it does explain the origin of the
  error.

* bpo-36016: "gc.get_objects" can now receive an optional parameter
  indicating a generation to get objects from. Patch by Pablo Galindo.

* bpo-1054041: When the main interpreter exits due to an uncaught
  KeyboardInterrupt, the process now exits in the appropriate manner
  for its parent process to detect that a SIGINT or ^C terminated the
  process.  This allows shells and batch scripts to understand that
  the user has asked them to stop.

* bpo-35992: Fix "__class_getitem__()" not being called on a class
  with a custom non-subscriptable metaclass.

* bpo-35993: Fix a crash on fork when using subinterpreters.
  Contributed by Stéphane Wirtel

* bpo-35991: Fix a potential double free in Modules/_randommodule.c.

* bpo-35961: Fix a crash in slice_richcompare(): use strong
  references rather than stolen references for the two temporary
  internal tuples.

* bpo-35911: Enable the creation of cell objects by adding a
  "cell.__new__" method, and expose the type "cell" in "Lib/types.py"
  under the name CellType. Patch by Pierre Glaser.

* bpo-12822: Use monotonic clock for "pthread_cond_timedwait" when
  "pthread_condattr_setclock" and "CLOCK_MONOTONIC" are available.

* bpo-15248: The compiler emits now syntax warnings in the case when
  a comma is likely missed before tuple or list.

* bpo-35886: The implementation of PyInterpreterState has been moved
  into the internal header files (guarded by Py_BUILD_CORE).

* bpo-31506: Clarify the errors reported when "object.__new__" and
  "object.__init__" receive more than one argument. Contributed by
  Sanyam Khurana.

* bpo-35724: Signal-handling is now guaranteed to happen relative to
  the main interpreter.

* bpo-33608: We added a new internal _Py_AddPendingCall() that
  operates relative to the provided interpreter.  This allows us to
  use the existing implementation to ask another interpreter to do
  work that cannot be done in the current interpreter, like decref an
  object the other interpreter owns.  The existing Py_AddPendingCall()
  only operates relative to the main interpreter.

* bpo-33989: Fix a possible crash in "list.sort()" when sorting
  objects with "ob_type->tp_richcompare == NULL".  Patch by Zackery
  Spytz.


库
--

* bpo-35512: "unittest.mock.patch.dict()" used as a decorator with
  string target resolves the target during function call instead of
  during decorator construction. Patch by Karthikeyan Singaravelan.

* bpo-36018: Add statistics.NormalDist, a tool for creating and
  manipulating normal distributions of random variable.  Features a
  composite class that treats the mean and standard deviation of
  measurement data as single entity.

* bpo-35904: Added statistics.fmean() as a faster, floating point
  variant of the existing mean() function.

* bpo-35918: Removed broken "has_key" method from
  multiprocessing.managers.SyncManager.dict. Contributed by Rémi
  Lapeyre.

* bpo-18283: Add support for bytes to "shutil.which()".

* bpo-35960: Fix "dataclasses.field()" throwing away empty mapping
  objects passed as metadata.

* bpo-35500: Write expected and actual call parameters on separate
  lines in "unittest.mock.Mock.assert_called_with()" assertion errors.
  Contributed by Susan Su.

* bpo-35931: The "pdb" "debug" command now gracefully handles syntax
  errors.

* bpo-24209: In http.server script, rely on getaddrinfo to bind to
  preferred address based on the bind parameter. Now default bind or
  binding to a name may bind to IPv6 or dual-stack, depending on the
  environment.

* bpo-35321: Set "__spec__.origin" of  "_frozen_importlib" to frozen
  so that it matches the behavior of "_frozen_importlib_external".
  Patch by Nina Zakharenko.

* bpo-35378: Fix a reference issue inside "multiprocessing.Pool"
  that caused the pool to remain alive if it was deleted without being
  closed or terminated explicitly. A new strong reference is added to
  the pool iterators to link the lifetime of the pool to the lifetime
  of its iterators so the pool does not get destroyed if a pool
  iterator is still alive.

* bpo-34294: re module, fix wrong capturing groups in rare cases.
  "re.search()", "re.findall()", "re.sub()" and other functions that
  scan through string looking for a match, should reset capturing
  groups between two match attempts. Patch by Ma Lin.

* bpo-35615: "weakref": Fix a RuntimeError when copying a
  WeakKeyDictionary or a WeakValueDictionary, due to some keys or
  values disappearing while iterating.

* bpo-35606: Implement "math.prod()" as analogous function to
  "sum()" that returns the product of a 'start' value (default: 1)
  times an iterable of numbers. Patch by Pablo Galindo.

* bpo-32417: Performing arithmetic between "datetime.datetime"
  subclasses and "datetime.timedelta" now returns an object of the
  same type as the "datetime.datetime" subclass. As a result,
  "datetime.datetime.astimezone()" and alternate constructors like
  "datetime.datetime.now()" and "datetime.fromtimestamp()" called with
  a "tz" argument now *also* retain their subclass.

* bpo-35153: Add *headers* optional keyword-only parameter to
  "xmlrpc.client.ServerProxy", "xmlrpc.client.Transport" and
  "xmlrpc.client.SafeTransport".  Patch by Cédric Krier.

* bpo-34572: Fix C implementation of pickle.loads to use importlib's
  locking mechanisms, and thereby avoid using partially-loaded
  modules. Patch by Tim Burgess.


文档
----

* bpo-36083: Fix formatting of --check-hash-based-pycs options in
  the manpage Synopsis.

* bpo-36007: Bump minimum sphinx version to 1.8.  Patch by Anthony
  Sottile.

* bpo-22062: Update documentation and docstrings for pathlib.
  Original patch by Mike Short.


测试
----

* bpo-27313: Avoid test_ttk_guionly ComboboxTest failure with macOS
  Cocoa Tk.

* bpo-36019: Add test.support.TEST_HTTP_URL and replace references
  of http://www.example.com by this new constant. Contributed by
  Stéphane Wirtel.

* bpo-36037: Fix test_ssl for strict OpenSSL configuration like
  RHEL8 strict crypto policy. Use older TLS version for minimum TLS
  version of the server SSL context if needed, to test TLS version
  older than default minimum TLS version.

* bpo-35798: Added "test.support.check_syntax_warning()".

* bpo-35505: Make test_imap4_host_default_value independent on
  whether the local IMAP server is running.

* bpo-35917: multiprocessing: provide unit tests for SyncManager and
  SharedMemoryManager classes + all the shareable types which are
  supposed to be supported by them.  (patch by Giampaolo Rodola)

* bpo-35704: Skip "test_shutil.test_unpack_archive_xztar" to prevent
  a MemoryError on 32-bit AIX when MAXDATA setting is less than
  0x20000000.

  Patch by Michael Felt (aixtools)

* bpo-34720: Assert m_state != NULL to mimic GC traversal functions
  that do not correctly handle module creation when the module state
  has not been created.


Windows
-------

* bpo-35976: Added ARM build support to Windows build files in
  PCBuild.

* bpo-35692: "pathlib" no longer raises when checking file and
  directory existence on drives that are not ready

* bpo-35872: Uses the base Python executable when invoking venv in a
  virtual environment

* bpo-35873: Prevents venv paths being inherited by child processes

* bpo-35299: Fix sysconfig detection of the source directory and
  distutils handling of pyconfig.h during PGO profiling


IDLE
----

* bpo-24310: IDLE -- Document settings dialog font tab sample.

* bpo-35833: Revise IDLE doc for control codes sent to Shell. Add a
  code example block.

* bpo-35689: Add docstrings and unittests for colorizer.py.


Python 3.8.0 alpha 1
====================

*Release date: 2019-02-03*


安全
----

* bpo-35746: [CVE-2019-5010] Fix a NULL pointer deref in ssl module.
  The cert parser did not handle CRL distribution points with empty DP
  or URI correctly. A malicious or buggy certificate can result into
  segfault. Vulnerability (TALOS-2018-0758) reported by Colin Read and
  Nicolas Edet of Cisco.

* bpo-34812: The "-I" command line option (run Python in isolated
  mode) is now also copied by the "multiprocessing" and "distutils"
  modules when spawning child processes. Previously, only "-E" and
  "-s" options (enabled by "-I") were copied.

* bpo-34791: The xml.sax and xml.dom.domreg no longer use
  environment variables to override parser implementations when
  sys.flags.ignore_environment is set by -E or -I arguments.

* bpo-17239: The xml.sax and xml.dom.minidom parsers no longer
  processes external entities by default. External DTD and ENTITY
  declarations no longer load files or create network connections.

* bpo-34623: CVE-2018-14647: The C accelerated _elementtree module
  now initializes hash randomization salt from _Py_HashSecret instead
  of libexpat's default CSPRNG.

* bpo-34405: Updated to OpenSSL 1.1.0i for Windows builds.

* bpo-33871: 修复了使用 "os.sendfile()" 在macOS上发送部分文件的错误
  。 使用 *trailers* 参数可能导致从输入文件发送的字节数多于指定的数量
  。

* bpo-32533: Fixed thread-safety of error handling in _ssl.

* bpo-33136: Harden ssl module against LibreSSL CVE-2018-8970.
  X509_VERIFY_PARAM_set1_host() is called with an explicit namelen. A
  new test ensures that NULL bytes are not allowed.

* bpo-33001: Minimal fix to prevent buffer overrun in os.symlink on
  Windows

* bpo-32981: Regexes in difflib and poplib were vulnerable to
  catastrophic backtracking. These regexes formed potential DOS
  vectors (REDOS). They have been refactored. This resolves
  CVE-2018-1060 and CVE-2018-1061. Patch by Jamie Davis.

* bpo-28414: The ssl module now allows users to perform their own
  IDN en/decoding when using SNI.


核心与内置
----------

* bpo-35877: Make parenthesis optional for named expressions in
  while statement. Patch by Karthikeyan Singaravelan.

* bpo-35814: Allow same right hand side expressions in annotated
  assignments as in normal ones. In particular, "x: Tuple[int, int] =
  1, 2" (without parentheses on the right) is now allowed.

* bpo-35766: Add the option to parse PEP 484 type comments in the
  ast module. (Off by default.) This is merging the key functionality
  of the third party fork thereof,
  [typed_ast](https://github.com/python/typed_ast).

* bpo-35713: Reorganize Python initialization to get working
  exceptions and sys.stderr earlier.

* bpo-33416: Add end line and end column position information to the
  Python AST nodes. This is a C-level backwards incompatible change.

* bpo-35720: Fixed a minor memory leak in pymain_parse_cmdline_impl
  function in Modules/main.c

* bpo-35634: "func(**kwargs)" will now raise an error when "kwargs"
  is a mapping containing multiple entries with the same key. An error
  was already raised when other keyword arguments are passed before
  "**kwargs" since Python 3.6.

* bpo-35623: 修复了在排序超长列表时崩溃的问题。 补丁作者 Stephan
  Hohe 。

* bpo-35214: 添加了 clang Memory Sanitizer 构建工具以绕过来自 posix,
  socket, time, test_io 和 test_faulthandler 的误报问题。

* bpo-35560: 修复了在调试版中使用 "n" 格式进行零留空和小宽度的浮点格
  式 化时 "format()" 内的一个断言错误。 发布版未受影响。 补丁作者
  Karthikeyan Singaravelan。

* bpo-35552: Format characters "%s" and "%V" in
  "PyUnicode_FromFormat()" and "%s" in "PyBytes_FromFormat()" no
  longer read memory past the limit if *precision* is specified.

* bpo-35504: 修复了在删除特定属性时的段错误和 "SystemError" 问题。
  补 丁作者 Zackery Spytz。

* bpo-35504: Fixed a SystemError when delete the characters_written
  attribute of an OSError.

* bpo-35494: Improved syntax error messages for unbalanced
  parentheses in f-string.

* bpo-35444: Fixed error handling in pickling methods when fail to
  look up builtin "getattr". Sped up pickling iterators.

* bpo-35436: Fix various issues with memory allocation error
  handling. Patch by Zackery Spytz.

* bpo-35423: Separate the signal handling trigger in the eval loop
  from the "pending calls" machinery. There is no semantic change and
  the difference in performance is insignificant.

* bpo-35357: Internal attributes' names of unittest.mock._Call and
  unittest.mock.MagicProxy (name, parent & from_kall) are now prefixed
  with _mock_ in order to prevent clashes with widely used object
  attributes. Fixed minor typo in test function name.

* bpo-35372: Fixed the code page decoder for input longer than 2 GiB
  containing undecodable bytes.

* bpo-35336: Fix PYTHONCOERCECLOCALE=1 environment variable: only
  coerce the C locale if the LC_CTYPE locale is "C".

* bpo-31241: The *lineno* and *col_offset* attributes of AST nodes
  for list comprehensions, generator expressions and tuples are now
  point to the opening parenthesis or square brace. For tuples without
  parenthesis they point to the position of the first item.

* bpo-33954: For "str.format()", "float.__format__()" and
  "complex.__format__()" methods for non-ASCII decimal point when
  using the "n" formatter.

* bpo-35269: Fix a possible segfault involving a newly-created
  coroutine. Patch by Zackery Spytz.

* bpo-35224: Implement **PEP 572** (assignment expressions). Patch
  by Emily Morehouse.

* bpo-32492: Speed up "namedtuple" attribute access by 1.6x using a
  C fast-path for the name descriptors. Patch by Pablo Galindo.

* bpo-35214: Fixed an out of bounds memory access when parsing a
  truncated unicode escape sequence at the end of a string such as
  "'\N'".  It would read one byte beyond the end of the memory
  allocation.

* bpo-35214: The interpreter and extension modules have had
  annotations added so that they work properly under clang's Memory
  Sanitizer.  A new configure flag --with-memory-sanitizer has been
  added to make test builds of this nature easier to perform.

* bpo-35193: Fix an off by one error in the bytecode peephole
  optimizer where it could read bytes beyond the end of bounds of an
  array when removing unreachable code. This bug was present in every
  release of Python 3.6 and 3.7 until now.

* bpo-35169: Improved error messages for forbidden assignments.

* bpo-34022: Fix handling of hash-based bytecode files in
  "zipimport". Patch by Elvis Pranskevichus.

* bpo-28401: Debug builds will no longer to attempt to import
  extension modules built for the ABI as they were never compatible to
  begin with. Patch by Stefano Rivera.

* bpo-29341: Clarify in the docstrings of "os" methods that path-
  like objects are also accepted as input parameters.

* bpo-35050: "socket": Fix off-by-one bug in length check for
  "AF_ALG" name and type.

* bpo-29743: Raise "ValueError" instead of "OverflowError" in case
  of a negative "_length_" in a "ctypes.Array" subclass.  Also raise
  "TypeError" instead of "AttributeError" for non-integer "_length_".
  Original patch by Oren Milman.

* bpo-16806: Fix "lineno" and "col_offset" for multi-line string
  tokens.

* bpo-35029: "SyntaxWarning" raised as an exception at code
  generation time will be now replaced with a "SyntaxError" for better
  error reporting.

* bpo-34983: Expose "symtable.Symbol.is_nonlocal()" in the symtable
  module. Patch by Pablo Galindo.

* bpo-34974: "bytes" and "bytearray" constructors no longer convert
  unexpected exceptions (e.g. "MemoryError" and "KeyboardInterrupt")
  to "TypeError".

* bpo-34939: Allow annotated names in module namespace that are
  declared global before the annotation happens. Patch by Pablo
  Galindo.

* bpo-34973: Fixed crash in "bytes()" when the "list" argument is
  mutated while it is iterated.

* bpo-34876: The *lineno* and *col_offset* attributes of the AST for
  decorated function and class refer now to the position of the
  corresponding "def", "async def" and "class" instead of the position
  of the first decorator. This leads to more correct line reporting in
  tracing. This is the only case when the position of child AST nodes
  can precede the position of the parent AST node.

* bpo-34879: Fix a possible null pointer dereference in
  bytesobject.c. Patch by Zackery Spytz.

* bpo-34784: Fix the implementation of PyStructSequence_NewType in
  order to create heap allocated StructSequences.

* bpo-32912: A "SyntaxWarning" is now emitted instead of a
  "DeprecationWarning" for invalid escape sequences in string and
  bytes literals.

* bpo-34854: 修复问题——当编译包含一个没有默认值的关键字参数的 lambda
  的字符串注解时可导致崩溃。

* bpo-34850: The compiler now produces a "SyntaxWarning" when
  identity checks ("is" and "is not") are used with certain types of
  literals (e.g. strings, ints).  These can often work by accident in
  CPython, but are not guaranteed by the language spec.  The warning
  advises users to use equality tests ("==" and "!=") instead.

* bpo-34824: Fix a possible null pointer dereference in
  Modules/_ssl.c. Patch by Zackery Spytz.

* bpo-30156: The C function "property_descr_get()" uses a "cached"
  tuple to optimize function calls. But this tuple can be discovered
  in debug mode with "sys.getobjects()". Remove the optimization, it's
  not really worth it and it causes 3 different crashes last years.

* bpo-34762: Fix contextvars C API to use PyObject* pointer types.

* bpo-34751: The hash function for tuples is now based on xxHash
  which gives better collision results on (formerly) pathological
  cases. Additionally, on 64-bit systems it improves tuple hashes in
  general. Patch by Jeroen Demeyer with substantial contributions by
  Tim Peters.

* bpo-34735: Fix a memory leak in Modules/timemodule.c.  Patch by
  Zackery Spytz.

* bpo-34683: Fixed a bug where some SyntaxError error pointed to
  locations that were off-by-one.

* bpo-34651: Only allow the main interpreter to fork.  The avoids
  the possibility of affecting the main interpreter, which is critical
  to operation of the runtime.

* bpo-34653: Remove unused function
  PyParser_SimpleParseStringFilename.

* bpo-32236: Warn that line buffering is not supported if "open()"
  is called with binary mode and "buffering=1".

* bpo-34641: Further restrict the syntax of the left-hand side of
  keyword arguments in function calls. In particular,
  "f((keyword)=arg)" is now disallowed.

* bpo-34637: Make the *start* argument to *sum()* visible as a
  keyword argument.

* bpo-1621: Do not assume signed integer overflow behavior (C
  undefined behavior) when performing set hash table resizing.

* bpo-34588: Fix an off-by-one in the recursive call pruning feature
  of traceback formatting.

* bpo-34485: On Windows, the LC_CTYPE is now set to the user
  preferred locale at startup. Previously, the LC_CTYPE locale was "C"
  at startup, but changed when calling setlocale(LC_CTYPE, "") or
  setlocale(LC_ALL, "").

* bpo-34485: Standard streams like sys.stdout now use the
  "surrogateescape" error handler, instead of "strict", on the POSIX
  locale (when the C locale is not coerced and the UTF-8 Mode is
  disabled).

* bpo-34485: Fix the error handler of standard streams like
  sys.stdout: PYTHONIOENCODING=":" is now ignored instead of setting
  the error handler to "strict".

* bpo-34485: Python now gets the locale encoding with C code to
  initialize the encoding of standard streams like sys.stdout.
  Moreover, the encoding is now initialized to the Python codec name
  to get a normalized encoding name and to ensure that the codec is
  loaded. The change avoids importing _bootlocale and _locale modules
  at startup by default.

* bpo-34527: On FreeBSD, Py_DecodeLocale() and Py_EncodeLocale() now
  also forces the ASCII encoding if the LC_CTYPE locale is "POSIX",
  not only if the LC_CTYPE locale is "C".

* bpo-34527: The UTF-8 Mode is now also enabled by the "POSIX"
  locale, not only by the "C" locale.

* bpo-34403: On HP-UX with C or POSIX locale,
  sys.getfilesystemencoding() now returns "ascii" instead of "roman8"
  (when the UTF-8 Mode is disabled and the C locale is not coerced).

* bpo-34523: The Python filesystem encoding is now read earlier
  during the Python initialization.

* bpo-12458: Tracebacks show now correct line number for
  subexpressions in multiline expressions. Tracebacks show now the
  line number of the first line for multiline expressions instead of
  the line number of the last subexpression.

* bpo-34408: Prevent a null pointer dereference and resource leakage
  in "PyInterpreterState_New()".

* bpo-34400: Fix undefined behavior in parsetok.c.  Patch by Zackery
  Spytz.

* bpo-33073: Added as_integer_ratio to ints to make them more
  interoperable with floats.

* bpo-34377: 更新valgrind的抑制列表，使用
  "_PyObject_Free"/"_PyObject_Realloc" 代替
  "PyObject_Free"/"PyObject_Realloc" 。

* bpo-34353: Added the "socket" option in the "stat.filemode()"
  Python implementation to match the C implementation.

* bpo-34320: 修复问题——"dict(od)" 不会复制 OrderedDict 的迭代顺序。

* bpo-34113: Fixed crash on debug builds when opcode stack was
  adjusted with negative numbers. Patch by Constantin Petrisor.

* bpo-34100: Compiler now merges constants in tuples and frozensets
  recursively. Code attributes like "co_names" are merged too.

* bpo-34151: Performance of list concatenation, repetition and
  slicing operations is slightly improved. Patch by Sergey Fedoseev.

* bpo-34170: -X dev: 即使启用了开发模式，现在也可以使用PYTHONMALLOC
  重 载内存分配器。

* bpo-33237: Improved "AttributeError" message for partially
  initialized module.

* bpo-34149: Fix min and max functions to get default behavior when
  key is None.

* bpo-34125: Profiling of unbound built-in methods now works when
  "**kwargs" is given.

* bpo-34141: Optimized pickling atomic types (None, bool, int,
  float, bytes, str).

* bpo-34126: 修复在分析某些未绑定的方法的无效调用时崩溃的问题。由
  Jeroen Demeyer修复。

* bpo-24618: 修复了当创建代码对象时使用的变量名元组太小或参数太多导
  致 读取无效内存的问题。

* bpo-34068: 在调用 "io.IOBase.close()" 时确保 "closed" 属性未设置有
  效 的异常。 由Zackery Spytz和Serhiy Storchaka修复。

* bpo-34087: 修复由unicode转换为数值类型时缓冲区溢出的问题。

* bpo-34080: 修复了编译器在标记化过程中引发一些不常见错误时内存泄漏
  的 问题。

* bpo-34066: 调用 "open()" 和进入  "with open()" 的 **with** 语句块
  内 时禁止使用 Ctrl-C 中断。

* bpo-34042: 修复 dict.copy() 以维护正确的总引用计数（由
  sys.gettotalrefcount()报告）。

* bpo-33418: Fix potential memory leak in function object when it
  creates reference cycle.

* bpo-33985: 实现contextvars.ContextVar.name 属性。

* bpo-33956: Update vendored Expat library copy to version 2.2.5.

* bpo-24596: 执行 "PyErr_Print()" 之前，在
  "PyRun_SimpleFileExFlags()" 内减少模块对象的引用。 由Zackery Spytz修
  复。

* bpo-33451: 执行 "PyEval_EvalCode()" 前先关闭直接执行的pyc文件。

* bpo-1617161: The hash of "BuiltinMethodType" instances (methods of
  built-in classes) now depends on the hash of the identity of
  *__self__* instead of its value. The hash and equality of
  "ModuleType" and "MethodWrapperType" instances (methods of user-
  defined classes and some methods of built-in classes like
  "str.__add__") now depend on the hash and equality of the identity
  of *__self__* instead of its value. "MethodWrapperType" instances no
  longer support ordering.

* bpo-33824: 修复"LC_ALL=C python3.7 -V"：在读取Python配置后编码发生
  更 改时，正确重置命令行解析器。

* bpo-33803: Fix a crash in hamt.c caused by enabling GC tracking
  for an object that hadn't all of its fields set to NULL.

* bpo-33738: Seven macro incompatibilities with the Limited API were
  fixed, and the macros "PyIter_Check()", "PyIndex_Check()" and
  "PyExceptionClass_Name()" were added as functions. A script for
  automatic macro checks was added.

* bpo-33786: Fix asynchronous generators to handle GeneratorExit in
  athrow() correctly

* bpo-30167: "PyRun_SimpleFileExFlags" removes "__cached__" from
  module in addition to "__file__".

* bpo-33706: Fix a crash in Python initialization when parsing the
  command line options. Thanks Christoph Gohlke for the bug report and
  the fix!

* bpo-33597: Reduce "PyGC_Head" size from 3 words to 2 words.

* bpo-30654: Fixed reset of the SIGINT handler to SIG_DFL on
  interpreter shutdown even when there was a custom handler set
  previously. Patch by Philipp Kerling.

* bpo-33622: Fixed a leak when the garbage collector fails to add an
  object with the "__del__" method or referenced by it into the
  "gc.garbage" list. "PyGC_Collect()" can now be called when an
  exception is set and preserves it.

* bpo-33462: Make dict and dict views reversible. Patch by Rémi
  Lapeyre.

* bpo-23722: A "RuntimeError" is now raised when the custom
  metaclass doesn't provide the "__classcell__" entry in the namespace
  passed to "type.__new__".  A "DeprecationWarning" was emitted in
  Python 3.6-- 3.7.

* bpo-33499: Add "PYTHONPYCACHEPREFIX" environment variable and "-X"
  "pycache_prefix" command-line option to set an alternate root
  directory for writing module bytecode cache files.

* bpo-25711: The "zipimport" module has been rewritten in pure
  Python.

* bpo-33509: Fix module_globals parameter of
  warnings.warn_explicit(): don't crash if module_globals is not a
  dict.

* bpo-31849: Fix signed/unsigned comparison warning in pyhash.c.

* bpo-33475: Fixed miscellaneous bugs in converting annotations to
  strings and optimized parentheses in the string representation.

* bpo-20104: Added support for the "setpgroup", "resetids",
  "setsigmask", "setsigdef" and "scheduler" parameters of
  "posix_spawn". Patch by Pablo Galindo.

* bpo-33391: Fix a leak in set_symmetric_difference().

* bpo-33363: 在异步函数外使用``async with`` 和 "async for"  时抛出
  SyntaxError异常。

* bpo-28055: Fix unaligned accesses in siphash24(). Patch by Rolf
  Eike Beer.

* bpo-33128: 修复导致PathFinder在sys.meta_path上出现两次的错误。由
  Pablo Galindo Salgado提供补丁。

* bpo-33331: Modules imported last are now cleared first at
  interpreter shutdown.

* bpo-33312: Fixed clang ubsan (undefined behavior sanitizer)
  warnings in dictobject.c by adjusting how the internal struct
  _dictkeysobject shared keys structure is declared.

* bpo-33305: Improved syntax error messages for invalid numerical
  literals.

* bpo-33306: Improved syntax error messages for unbalanced
  parentheses.

* bpo-33234: The list constructor will pre-size and not over-
  allocate when the input length is known.

* bpo-33270: Intern the names for all anonymous code objects.  Patch
  by Zackery Spytz.

* bpo-30455: The C and Python code and the documentation related to
  tokens are now generated from a single source file "Grammar/Tokens".

* bpo-33176: Add a "toreadonly()" method to memoryviews.

* bpo-33231: 修复 "normalizestring()" 中潜在的内存泄漏。

* bpo-33205: Change dict growth function from
  "round_up_to_power_2(used*2+hashtable_size/2)" to
  "round_up_to_power_2(used*3)".  Previously, dict is shrinked only
  when "used == 0". Now dict has more chance to be shrinked.

* bpo-29922: Improved error messages in 'async with' when
  "__aenter__()" or "__aexit__()" return non-awaitable object.

* bpo-33199: Fix "ma_version_tag" in dict implementation is
  uninitialized when copying from key-sharing dict.

* bpo-33053: When using the -m switch, sys.path[0] is now explicitly
  expanded as the *starting* working directory, rather than being left
  as the empty path (which allows imports from the current working
  directory at the time of the import)

* bpo-33138: Changed standard error message for non-pickleable and
  non-copyable types. It now says "cannot pickle" instead of "can't
  pickle" or "cannot serialize".

* bpo-33018: Improve consistency of errors raised by "issubclass()"
  when called with a non-class and an abstract base class as the first
  and second arguments, respectively. Patch by Josh Bronson.

* bpo-33083: "math.factorial" no longer accepts arguments that are
  not int-like. Patch by Pablo Galindo.

* bpo-33041: Added new opcode "END_ASYNC_FOR" and fixes the
  following issues:

  * Setting global "StopAsyncIteration" no longer breaks "async for"
    loops.

  * Jumping into an "async for" loop is now disabled.

  * Jumping out of an "async for" loop no longer corrupts the stack.

* bpo-25750: Fix rare Python crash due to bad refcounting in
  "type_getattro()" if a descriptor deletes itself from the class.
  Patch by Jeroen Demeyer.

* bpo-33041: Fixed bytecode generation for "async for" with a
  complex target. A StopAsyncIteration raised on assigning or
  unpacking will be now propagated instead of stopping the iteration.

* bpo-33026: Fixed jumping out of "with" block by setting f_lineno.

* bpo-33005: Fix a crash on fork when using a custom memory
  allocator (ex: using PYTHONMALLOC env var). _PyGILState_Reinit() and
  _PyInterpreterState_Enable() now use the default RAW memory
  allocator to allocate a new interpreters mutex on fork.

* bpo-32911: Due to unexpected compatibility issues discovered
  during downstream beta testing, reverted bpo-29463. "docstring"
  field is removed from Module, ClassDef, FunctionDef, and
  AsyncFunctionDef ast nodes which was added in 3.7a1.  Docstring
  expression is restored as a first statement in their body. Based on
  patch by Inada Naoki.

* bpo-17288: Prevent jumps from 'return' and 'exception' trace
  events.

* bpo-32946: Importing names from already imported module with "from
  ... import ..." is now 30% faster if the module is not a package.

* bpo-32932: Make error message more revealing when there are non-
  str objects in "__all__".

* bpo-32925: Optimized iterating and containing test for literal
  lists consisting of non-constants: "x in [a, b]" and "for x in [a,
  b]". The case of all constant elements already was optimized.

* bpo-32889: Update Valgrind suppression list to account for the
  rename of "Py_ADDRESS_IN_RANG" to "address_in_range".

* bpo-32836: Don't use temporary variables in cases of list/dict/set
  comprehensions

* bpo-31356: Remove the new API added in bpo-31356
  (gc.ensure_disabled() context manager).

* bpo-32305: For namespace packages, ensure that both "__file__" and
  "__spec__.origin" are set to None.

* bpo-32303: Make sure "__spec__.loader" matches "__loader__" for
  namespace packages.

* bpo-32711: Fix the warning messages for Python/ast_unparse.c.
  Patch by Stéphane Wirtel

* bpo-32583: Fix possible crashing in builtin Unicode decoders
  caused by write out-of-bound errors when using customized decode
  error handlers.

* bpo-32489: A "continue" statement is now allowed in the "finally"
  clause.

* bpo-17611: Simplified the interpreter loop by moving the logic of
  unrolling the stack of blocks into the compiler. The compiler emits
  now explicit instructions for adjusting the stack of values and
  calling the cleaning up code for "break", "continue" and "return".

  Removed opcodes "BREAK_LOOP", "CONTINUE_LOOP", "SETUP_LOOP" and
  "SETUP_EXCEPT". Added new opcodes "ROT_FOUR", "BEGIN_FINALLY" and
  "CALL_FINALLY" and "POP_FINALLY". Changed the behavior of
  "END_FINALLY" and "WITH_CLEANUP_START".

* bpo-32285: New function unicodedata.is_normalized, which can check
  whether a string is in a specific normal form.

* bpo-10544: Yield expressions are now disallowed in comprehensions
  and generator expressions except the expression for the outermost
  iterable.

* bpo-32117: Iterable unpacking is now allowed without parentheses
  in yield and return statements, e.g. "yield 1, 2, 3, *rest". Thanks
  to David Cuthbert for the change and Jordan Chapman for added tests.

* bpo-31902: Fix the "col_offset" attribute for ast nodes
  "ast.AsyncFor", "ast.AsyncFunctionDef", and "ast.AsyncWith".
  Previously, "col_offset" pointed to the keyword after "async".

* bpo-25862: 修复 "io.TextIOWrapper" 的 "tell()" 方法内的错误断言。

* bpo-21983: Fix a crash in "ctypes.cast()" in case the type
  argument is a ctypes structured data type. Patch by Eryk Sun and
  Oren Milman.

* bpo-31577: Fix a crash in "os.utime()" in case of a bad ns
  argument. Patch by Oren Milman.

* bpo-29832: Remove references to 'getsockaddrarg' from various
  socket error messages. Patch by Oren Milman.


库
--

* bpo-35845: Add 'order' parameter to memoryview.tobytes().

* bpo-35864: The _asdict() method for collections.namedtuple now
  returns a regular dict instead of an OrderedDict.

* bpo-35537: An ExitStack is now used internally within
  subprocess.POpen to clean up pipe file handles. No behavior change
  in normal operation. But if closing one handle were ever to cause an
  exception, the others will now be closed instead of leaked.  (patch
  by Giampaolo Rodola)

* bpo-35847: RISC-V needed the CTYPES_PASS_BY_REF_HACK.  Fixes
  ctypes Structure test_pass_by_value.

* bpo-35813: Shared memory submodule added to multiprocessing to
  avoid need for serialization between processes

* bpo-35780: Fix lru_cache() errors arising in recursive, reentrant,
  or multi-threaded code. These errors could result in orphan links
  and in the cache being trapped in a state with fewer than the
  specified maximum number of links. Fix handling of negative maxsize
  which should have been treated as zero. Fix errors in toggling the
  "full" status flag. Fix misordering of links when errors are
  encountered.  Sync-up the C code and pure Python code for the space
  saving path in functions with a single positional argument. In this
  common case, the space overhead of an lru cache entry is reduced by
  almost half.  Fix counting of cache misses. In error cases, the miss
  count was out of sync with the actual number of times the underlying
  user function was called.

* bpo-35537: "os.posix_spawn()" and "os.posix_spawnp()" now have a
  *setsid* parameter.

* bpo-23846: "asyncio.ProactorEventLoop" now catches and logs send
  errors when the self-pipe is full.

* bpo-34323: "asyncio": Enhance "IocpProactor.close()" log: wait 1
  second before the first log, then log every second. Log also the
  number of seconds since "close()" was called.

* bpo-35674: Add a new "os.posix_spawnp()" function. Patch by
  Joannah Nanjekye.

* bpo-35733: "ast.Constant(boolean)" no longer an instance of
  "ast.Num".  Patch by Anthony Sottile.

* bpo-35726: QueueHandler.prepare() now makes a copy of the record
  before modifying and enqueueing it, to avoid affecting other
  handlers in the chain.

* bpo-35719: Sped up multi-argument "math" functions atan2(),
  copysign(), remainder() and hypot() by 1.3--2.5 times.

* bpo-35717: Fix KeyError exception raised when using enums and
  compile. Patch contributed by Rémi Lapeyre.

* bpo-35699: Fixed detection of Visual Studio Build Tools 2017 in
  distutils

* bpo-32710: Fix memory leaks in asyncio ProactorEventLoop on
  overlapped operation failure.

* bpo-35702: The "time.CLOCK_UPTIME_RAW" constant is now available
  for macOS 10.12.

* bpo-32710: Fix a memory leak in asyncio in the ProactorEventLoop
  when "ReadFile()" or "WSASend()" overlapped operation fail
  immediately: release the internal buffer.

* bpo-35682: Fix "asyncio.ProactorEventLoop.sendfile()": don't
  attempt to set the result of an internal future if it's already
  done.

* bpo-35283: Add a deprecated warning for the
  "threading.Thread.isAlive()" method. Patch by Dong-hee Na.

* bpo-35664: Improve operator.itemgetter() performance by 33% with
  optimized argument handling and with adding a fast path for the
  common case of a single non-negative integer index into a tuple
  (which is the typical use case in the standard library).

* bpo-35643: 修复了 Modules/_sha3/cleanup.py 中的一个 SyntaxWarning:
  invalid escape sequence。 补丁作者 Mickaël Schoentgen。

* bpo-35619: Improved support of custom data descriptors in "help()"
  and "pydoc".

* bpo-28503: 当库函数可用时 "crypt" 模块现在将在内部使用 "crypt_r()"
  而非 "crypt()"。

* bpo-35614: Fixed help() on metaclasses. Patch by Sanyam Khurana.

* bpo-35568: Expose "raise(signum)" as "raise_signal"

* bpo-35588: The floor division and modulo operations and the
  "divmod()" function on "fractions.Fraction" types are 2--4x faster.
  Patch by Stefan Behnel.

* bpo-35585: 加快构建按值枚举的速度，例如 http.HTTPStatus(200)。

* bpo-30561: random.gammavariate(1.0, beta) now computes the same
  result as random.expovariate(1.0 / beta).  This synchonizes the two
  algorithms and eliminates some idiosyncrasies in the old
  implementation.  It does however produce a difference stream of
  random variables than it used to.

* bpo-35537: The "subprocess" module can now use the
  "os.posix_spawn()" function in some cases for better performance.

* bpo-35526: Delaying the 'joke' of barry_as_FLUFL.mandatory to
  Python version 4.0

* bpo-35523: Remove "ctypes" callback workaround: no longer create a
  callback at startup. Avoid SELinux alert on "import ctypes" and
  "import uuid".

* bpo-31784: "uuid.uuid1()" now calls "time.time_ns()" rather than
  "int(time.time() * 1e9)".

* bpo-35513: "unittest.runner" 的 "TextTestRunner" 现在将使用
  "time.perf_counter()" 而非 "time.time()" 来计量一个测试的执行时间:
  "time.time()" 可以回退，而 "time.perf_counter()" 为单调递增。

* bpo-35502: 修复了构建树未完成的情况下
  "xml.etree.ElementTree.TreeBuilder" 中的引用泄漏（特别是在解析 XML
  期间引发错误的时候）。

* bpo-35348: Make "platform.architecture()" parsing of "file"
  command output more reliable: add the "-b" option to the "file"
  command to omit the filename, force the usage of the C locale, and
  search also the "shared object" pattern.

* bpo-35491: "multiprocessing": Add "Pool.__repr__()" and enhance
  "BaseProcess.__repr__()" (add pid and parent pid) to ease debugging.
  Pool state constant values are now strings instead of integers, for
  example "RUN" value becomes "'RUN'" instead of "0".

* bpo-35477: "multiprocessing.Pool.__enter__()" now fails if the
  pool is not running: "with pool:" fails if used more than once.

* bpo-31446: 复制被传递给 CreateProcessW 的命令行，因为此函数能改变
  输 入缓存的内容。

* bpo-35471: Python 2.4 dropped MacOS 9 support. The macpath module
  was deprecated in Python 3.7. The module is now removed.

* bpo-23057: Unblock Proactor event loop when keyboard interrupt is
  received on Windows

* bpo-35052: Fix xml.dom.minidom cloneNode() on a document with an
  entity: pass the correct arguments to the user data handler of an
  entity.

* bpo-20239: Allow repeated assignment deletion of
  "unittest.mock.Mock" attributes. Patch by Pablo Galindo.

* bpo-17185: 在 mock 上设置 "__signature__" 以便 "inspect" 能获得签
  名 。 补丁作者为 Karthikeyan Singaravelan。

* bpo-35445: Memory errors during creating posix.environ no longer
  ignored.

* bpo-35415: Validate fileno= argument to socket.socket().

* bpo-35424: "multiprocessing.Pool" destructor now emits
  "ResourceWarning" if the pool is still running.

* bpo-35330: When a "Mock" instance was used to wrap an object, if
  "side_effect" is used in one of the mocks of it methods, don't call
  the original implementation and return the result of using the side
  effect the same way that it is done with return_value.

* bpo-35346: Drop Mac OS 9 and Rhapsody support from the "platform"
  module. Rhapsody last release was in 2000. Mac OS 9 last release was
  in 2001.

* bpo-10496: "check_environ()" of "distutils.utils" now catches
  "KeyError" on calling "pwd.getpwuid()": don't create the "HOME"
  environment variable in this case.

* bpo-10496: "posixpath.expanduser()" now returns the input *path*
  unchanged if the "HOME" environment variable is not set and the
  current user has no home directory (if the current user identifier
  doesn't exist in the password database). This change fix the "site"
  module if the current user doesn't exist in the password database
  (if the user has no home directory).

* bpo-35389: "platform.libc_ver()" now uses
  "os.confstr('CS_GNU_LIBC_VERSION')" if available and the
  *executable* parameter is not set.

* bpo-35394: Add empty slots to asyncio abstract protocols.

* bpo-35310: Fix a bug in "select.select()" where, in some cases,
  the file descriptor sequences were returned unmodified after a
  signal interruption, even though the file descriptors might not be
  ready yet. "select.select()" will now always return empty lists if a
  timeout has occurred.  Patch by Oran Avraham.

* bpo-35380: Enable TCP_NODELAY on Windows for proactor asyncio
  event loop.

* bpo-35341: Add generic version of "collections.OrderedDict" to the
  "typing" module. Patch by Ismo Toijala.

* bpo-35371: Fixed possible crash in "os.utime()" on Windows when
  pass incorrect arguments.

* bpo-35346: "platform.uname()" now redirects "stderr" to
  "os.devnull" when running external programs like "cmd /c ver".

* bpo-35066: Previously, calling the strftime() method on a datetime
  object with a trailing '%' in the format string would result in an
  exception. However, this only occurred when the datetime C module
  was being used; the python implementation did not match this
  behavior. Datetime is now PEP-399 compliant, and will not throw an
  exception on a trailing '%'.

* bpo-35345: The function "platform.popen" has been removed, it was
  deprecated since Python 3.3: use "os.popen()" instead.

* bpo-35344: On macOS, "platform.platform()" now uses
  "platform.mac_ver()", if it returns a non-empty release string, to
  get the macOS version rather than the darwin version.

* bpo-35312: Make "lib2to3.pgen2.parse.ParseError" round-trip
  pickle- able. Patch by Anthony Sottile.

* bpo-35308: Fix regression in "webbrowser" where default browsers
  may be preferred over browsers in the "BROWSER" environment
  variable.

* bpo-24746: Avoid stripping trailing whitespace in doctest fancy
  diff. Original patch by R. David Murray & Jairo Trad. Enhanced by
  Sanyam Khurana.

* bpo-28604: "locale.localeconv()" now sets temporarily the
  "LC_CTYPE" locale to the "LC_MONETARY" locale if the two locales are
  different and monetary strings are non-ASCII. This temporary change
  affects other threads.

* bpo-35277: Update ensurepip to install pip 18.1 and setuptools
  40.6.2.

* bpo-24209: Adds IPv6 support when invoking http.server directly.

* bpo-35226: Recursively check arguments when testing for equality
  of "unittest.mock.call" objects and add note that tracking of
  parameters used to create ancestors of mocks in "mock_calls" is not
  possible.

* bpo-29564: The warnings module now suggests to enable tracemalloc
  if the source is specified, the tracemalloc module is available, but
  tracemalloc is not tracing memory allocations.

* bpo-35189: Modify the following fnctl function to retry if
  interrupted by a signal (EINTR): flock, lockf, fnctl

* bpo-30064: Use add_done_callback() in sock_* asyncio API to
  unsubscribe reader/writer early on calcellation.

* bpo-35186: Removed the "built with" comment added when "setup.py
  upload" is used with either "bdist_rpm" or "bdist_dumb".

* bpo-35152: Allow sending more than 2 GB at once on a
  multiprocessing connection on non-Windows systems.

* bpo-35062: Fix incorrect parsing of
  "_io.IncrementalNewlineDecoder"'s *translate* argument.

* bpo-35065: Remove "StreamReaderProtocol._untrack_reader". The call
  to "_untrack_reader" is currently performed too soon, causing the
  protocol to forget about the reader before "connection_lost" can run
  and feed the EOF to the reader.

* bpo-34160: ElementTree and minidom now preserve the attribute
  order specified by the user.

* bpo-35079: Improve difflib.SequenceManager.get_matching_blocks doc
  by adding 'non-overlapping' and changing '!=' to '<'.

* bpo-33710: Deprecated "l*gettext()" functions and methods in the
  "gettext" module. They return encoded bytes instead of Unicode
  strings and are artifacts from Python 2 times. Also deprecated
  functions and methods related to setting the charset for
  "l*gettext()" functions and methods.

* bpo-35017: "socketserver.BaseServer.serve_forever()" now exits
  immediately if it's "shutdown()" method is called while it is
  polling for new events.

* bpo-35024: "importlib" no longer logs "wrote" redundantly after
  "(created|could not create)" is already logged. Patch by Quentin
  Agren.

* bpo-35047: "unittest.mock" now includes mock calls in exception
  messages if "assert_not_called", "assert_called_once", or
  "assert_called_once_with" fails. Patch by Petter Strandmark.

* bpo-31047: Fix "ntpath.abspath" regression where it didn't remove
  a trailing separator on Windows. Patch by Tim Graham.

* bpo-35053: tracemalloc now tries to update the traceback when an
  object is reused from a "free list" (optimization for faster object
  creation, used by the builtin list type for example).

* bpo-31553: Add the --json-lines option to json.tool. Patch by
  hongweipeng.

* bpo-34794: Fixed a leak in Tkinter when pass the Python wrapper
  around Tcl_Obj back to Tcl/Tk.

* bpo-34909: Enum: fix grandchildren subclassing when parent mixed
  with concrete data types.

* bpo-35022: "unittest.mock.MagicMock" now supports the "__fspath__"
  method (from "os.PathLike").

* bpo-35008: Fixed references leaks when call the "__setstate__()"
  method of "xml.etree.ElementTree.Element" in the C implementation
  for already initialized element.

* bpo-23420: Verify the value for the parameter '-s' of the cProfile
  CLI. Patch by Robert Kuska

* bpo-33947: dataclasses now handle recursive reprs without raising
  RecursionError.

* bpo-34890: Make "inspect.iscoroutinefunction()",
  "inspect.isgeneratorfunction()" and "inspect.isasyncgenfunction()"
  work with "functools.partial()". Patch by Pablo Galindo.

* bpo-34521: Use "socket.CMSG_SPACE()" to calculate ancillary data
  size instead of "socket.CMSG_LEN()" in
  "multiprocessing.reduction.recvfds()" as **RFC 3542** requires the
  use of the former for portable applications.

* bpo-31522: The "mailbox.mbox.get_string" function *from_*
  parameter can now successfully be set to a non-default value.

* bpo-34970: Protect tasks weak set manipulation in
  "asyncio.all_tasks()"

* bpo-34969: gzip: Add --fast, --best on the gzip CLI, these
  parameters will be used for the fast compression method (quick) or
  the best method compress (slower, but smaller file). Also, change
  the default compression level to 6 (tradeoff).

* bpo-16965: The *2to3* "execfile" fixer now opens the file with
  mode "'rb'".  Patch by Zackery Spytz.

* bpo-34966: "pydoc" now supports aliases not only to methods
  defined in the end class, but also to inherited methods.  The
  docstring is not duplicated for aliases.

* bpo-34926: "mimetypes.MimeTypes.guess_type()" now accepts *path-
  like object* in addition to url strings. Patch by Mayank Asthana.

* bpo-23831: Add "moveto()" method to the "tkinter.Canvas" widget.
  Patch by Juliette Monsel.

* bpo-34941: Methods "find()", "findtext()" and "findall()" of the
  "Element" class in the "xml.etree.ElementTree" module are now able
  to find children which are instances of "Element" subclasses.

* bpo-32680: "smtplib.SMTP" objects now always have a "sock"
  attribute present

* bpo-34769: Fix for async generators not finalizing when event loop
  is in debug mode and garbage collector runs in another thread.

* bpo-34936: Fix "TclError" in
  "tkinter.Spinbox.selection_element()". Patch by Juliette Monsel.

* bpo-34829: Add methods "selection_from", "selection_range",
  "selection_present" and "selection_to" to the "tkinter.Spinbox" for
  consistency with the "tkinter.Entry" widget. Patch by Juliette
  Monsel.

* bpo-34911: Added *secure_protocols* argument to
  *http.cookiejar.DefaultCookiePolicy* to allow for tweaking of
  protocols and also to add support by default for *wss*, the secure
  websocket protocol.

* bpo-34922: Fixed integer overflow in the "digest()" and
  "hexdigest()" methods for the SHAKE algorithm in the "hashlib"
  module.

* bpo-34925: 25% speedup in argument parsing for the functions in
  the bisect module.

* bpo-34900: Fixed "unittest.TestCase.debug()" when used to call
  test methods with subtests.  Patch by Bruno Oliveira.

* bpo-34844: logging.Formatter enhancement - Ensure styles and fmt
  matches in logging.Formatter - Added validate method in each format
  style class: StrFormatStyle, PercentStyle, StringTemplateStyle. -
  This method is called in the constructor of logging.Formatter class
  - Also re-raise the KeyError in the format method of each style
  class, so it would a bit clear that it's an error with the invalid
  format fields.

* bpo-34897: Adjust test.support.missing_compiler_executable check
  so that a nominal command name of "" is ignored. Patch by Michael
  Felt.

* bpo-34871: Fix inspect module polluted "sys.modules" when parsing
  "__text_signature__" of callable.

* bpo-34898: Add "mtime" argument to "gzip.compress" for
  reproducible output. Patch by Guo Ci Teo.

* bpo-28441: On Cygwin and MinGW, ensure that "sys.executable"
  always includes the full filename in the path, including the ".exe"
  suffix (unless it is a symbolic link).

* bpo-34866: Adding "max_num_fields" to "cgi.FieldStorage" to make
  DOS attacks harder by limiting the number of "MiniFieldStorage"
  objects created by "FieldStorage".

* bpo-34711: http.server ensures it reports HTTPStatus.NOT_FOUND
  when the local path ends with "/" and is not a directory, even if
  the underlying OS (e.g. AIX) accepts such paths as a valid file
  reference. Patch by Michael Felt.

* bpo-34872: Fix self-cancellation in C implementation of
  asyncio.Task

* bpo-34849: Don't log waiting for "selector.select" in asyncio loop
  iteration. The waiting is pretty normal for any asyncio program,
  logging its time just adds a noise to logs without any useful
  information provided.

* bpo-34022: The "SOURCE_DATE_EPOCH" environment variable no longer
  overrides the value of the *invalidation_mode* argument to
  "py_compile.compile()", and determines its default value instead.

* bpo-34819: 使用一个单一时钟计算 "Executor.map()" 和
  "as_completed()" 中的超时，以防止当系统时钟被修改时因偏离导致的超时
  。

* bpo-34758: Add .wasm -> application/wasm to list of recognized
  file types and content type headers

* bpo-34789: "xml.sax.make_parser()" now accepts any iterable as its
  *parser_list* argument.  Patch by Andrés Delfino.

* bpo-34334: In "QueueHandler", clear "exc_text" from "LogRecord" to
  prevent traceback from being written twice.

* bpo-34687: On Windows, asyncio now uses ProactorEventLoop, instead
  of SelectorEventLoop, by default.

* bpo-5950: Support reading zip files with archive comments in
  "zipimport".

* bpo-32892: The parser now represents all constants as
  "ast.Constant" instead of using specific constant AST types ("Num",
  "Str", "Bytes", "NameConstant" and "Ellipsis"). These classes are
  considered deprecated and will be removed in future Python versions.

* bpo-34728: Add deprecation warning when "loop" is used in methods:
  "asyncio.sleep", "asyncio.wait" and "asyncio.wait_for".

* bpo-34738: ZIP files created by "distutils" will now include
  entries for directories.

* bpo-34659: Add an optional *initial* argument to
  itertools.accumulate().

* bpo-29577: Support multiple mixin classes when creating Enums.

* bpo-34670: Add SSLContext.post_handshake_auth and
  SSLSocket.verify_client_post_handshake for TLS 1.3's post handshake
  authentication feature.

* bpo-32718: The Activate.ps1 script from venv works with PowerShell
  Core 6.1 and is now available under all operating systems.

* bpo-31177: Fix bug that prevented using "reset_mock" on mock
  instances with deleted attributes

* bpo-34672: Add a workaround, so the "'Z'" "time.strftime()"
  specifier on the musl C library can work in some cases.

* bpo-34666: Implement "asyncio.StreamWriter.awrite" and
  "asyncio.StreamWriter.aclose()" coroutines.  Methods are needed for
  providing a consistent stream API with control flow switched on by
  default.

* bpo-6721: Acquire the logging module's commonly used internal
  locks while fork()ing to avoid deadlocks in the child process.

* bpo-34658: Fix a rare interpreter unhandled exception state
  SystemError only seen when using subprocess with a preexec_fn while
  an after_parent handler has been registered with os.register_at_fork
  and the fork system call fails.

* bpo-34652: Ensure "os.lchmod()" is never defined on Linux.

* bpo-34638: Store a weak reference to stream reader to break strong
  references loop between reader and protocol.  It allows to detect
  and close the socket if the stream is deleted (garbage collected)
  without "close()" call.

* bpo-34536: "Enum._missing_":  raise "ValueError" if None returned
  and "TypeError" if non-member is returned.

* bpo-34636: Speed up re scanning of many non-matching characters
  for s w and d within bytes objects. (microoptimization)

* bpo-24412: Add "addModuleCleanup()" and "addClassCleanup()" to
  unittest to support cleanups for "setUpModule()" and "setUpClass()".
  Patch by Lisa Roach.

* bpo-34630: Don't log SSL certificate errors in asyncio code
  (connection error logging is skipped already).

* bpo-32490: Prevent filename duplication in "subprocess" exception
  messages.  Patch by Zackery Spytz.

* bpo-34363: dataclasses.asdict() and .astuple() now handle
  namedtuples correctly.

* bpo-34625: Update vendorized expat library version to 2.2.6.

* bpo-32270: The subprocess module no longer mistakenly closes
  redirected fds even when they were in pass_fds when outside of the
  default {0, 1, 2} set.

* bpo-34622: Create a dedicated "asyncio.CancelledError",
  "asyncio.InvalidStateError" and "asyncio.TimeoutError" exception
  classes.  Inherit them from corresponding exceptions from
  "concurrent.futures" package. Extract "asyncio" exceptions into a
  separate file.

* bpo-34610: Fixed iterator of "multiprocessing.managers.DictProxy".

* bpo-34421: Fix distutils logging for non-ASCII strings.  This
  caused installation issues on Windows.

* bpo-34604: Fix possible mojibake in the error message of
  "pwd.getpwnam" and "grp.getgrnam" using string representation
  because of invisible characters or trailing whitespaces. Patch by
  William Grzybowski.

* bpo-30977: Make uuid.UUID use "__slots__" to reduce its memory
  footprint. Based on original patch by Wouter Bolsterlee.

* bpo-34574: OrderedDict iterators are not exhausted during pickling
  anymore. Patch by Sergey Fedoseev.

* bpo-8110: Refactored "subprocess" to check for Windows-specific
  modules rather than "sys.platform == 'win32'".

* bpo-34530: "distutils.spawn.find_executable()" now falls back on
  "os.defpath" if the "PATH" environment variable is not set.

* bpo-34563: On Windows, fix multiprocessing.Connection for very
  large read: fix _winapi.PeekNamedPipe() and _winapi.ReadFile() for
  read larger than INT_MAX (usually 2^31-1).

* bpo-34558: Correct typo in Lib/ctypes/_aix.py

* bpo-34282: Move "Enum._convert" to "EnumMeta._convert_" and fix
  enum members getting shadowed by parent attributes.

* bpo-22872: When the queue is closed, "ValueError" is now raised by
  "multiprocessing.Queue.put()" and "multiprocessing.Queue.get()"
  instead of "AssertionError" and "OSError", respectively. Patch by
  Zackery Spytz.

* bpo-34515: Fix parsing non-ASCII identifiers in
  "lib2to3.pgen2.tokenize" (PEP 3131).

* bpo-13312: Avoids a possible integer underflow (undefined
  behavior) in the time module's year handling code when passed a very
  low negative year value.

* bpo-34472: Improved compatibility for streamed files in "zipfile".
  Previously an optional signature was not being written and certain
  ZIP applications were not supported. Patch by Silas Sewell.

* bpo-34454: Fix the .fromisoformat() methods of datetime types
  crashing when given unicode with non-UTF-8-encodable code points.
  Specifically, datetime.fromisoformat() now accepts surrogate unicode
  code points used as the separator. Report and tests by Alexey
  Izbyshev, patch by Paul Ganssle.

* bpo-6700: Fix inspect.getsourcelines for module level
  frames/tracebacks. Patch by Vladimir Matveev.

* bpo-34171: Running the "trace" module no longer creates the
  "trace.cover" file.

* bpo-34441: Fix crash when an "ABC"-derived class with invalid
  "__subclasses__" is passed as the second argument to "issubclass()".
  Patch by Alexey Izbyshev.

* bpo-34427: Fix infinite loop in "a.extend(a)" for
  "MutableSequence" subclasses.

* bpo-34412: Make "signal.strsignal()" work on HP-UX. Patch by
  Michael Osipov.

* bpo-20849: shutil.copytree now accepts a new "dirs_exist_ok"
  keyword argument. Patch by Josh Bronson.

* bpo-31715: Associate ".mjs" file extension with
  "application/javascript" MIME Type.

* bpo-34384: "os.readlink()" now accepts *path-like* and "bytes"
  objects on Windows.

* bpo-22602: The UTF-7 decoder now raises "UnicodeDecodeError" for
  ill-formed sequences starting with "+" (as specified in RFC 2152).
  Patch by Zackery Spytz.

* bpo-2122: The "mmap.flush()" method now returns "None" on success,
  raises an exception on error under all platforms.

* bpo-34341: Appending to the ZIP archive with the ZIP64 extension
  no longer grows the size of extra fields of existing entries.

* bpo-34333: 修复在 "pathlib.PurePath.with_suffix()" 内使用
  %-formatting 格式化错误信息的错误。

* bpo-18540: The "imaplib.IMAP4" and "imaplib.IMAP4_SSL" classes now
  resolve to the local host IP correctly when the default value of
  *host* parameter ("''") is used.

* bpo-26502: Implement "traceback.FrameSummary.__len__()" method to
  preserve compatibility with the old tuple API.

* bpo-34318: "assertRaises()", "assertRaisesRegex()",
  "assertWarns()" and "assertWarnsRegex()" no longer success if the
  passed callable is None. They no longer ignore unknown keyword
  arguments in the context manager mode. A DeprecationWarning was
  raised in these cases since Python 3.5.

* bpo-9372: Deprecate "__getitem__()" methods of
  "xml.dom.pulldom.DOMEventStream", "wsgiref.util.FileWrapper" and
  "fileinput.FileInput".

* bpo-33613: Fix a race condition in
  "multiprocessing.semaphore_tracker" when the tracker receives SIGINT
  before it can register signal handlers for ignoring it.

* bpo-34248: Report filename in the exception raised when the
  database file cannot be opened by "dbm.gnu.open()" and
  "dbm.ndbm.open()" due to OS-related error. Patch by Zsolt Cserna.

* bpo-33089: Add math.dist() to compute the Euclidean distance
  between two points.

* bpo-34246: "smtplib.SMTP.send_message()" no longer modifies the
  content of the *mail_options* argument. Patch by Pablo S. Blum de
  Aguiar.

* bpo-31047: Fix "ntpath.abspath" for invalid paths on windows.
  Patch by Franz Woellert.

* bpo-32321: Add pure Python fallback for functools.reduce. Patch by
  Robert Wright.

* bpo-34270: The default asyncio task class now always has a name
  which can be get or set using two new methods ("get_name()" and
  "set_name()") and is visible in the "repr()" output. An initial name
  can also be set using the new "name" keyword argument to
  "asyncio.create_task()" or the "create_task()" method of the event
  loop. If no initial name is set, the default Task implementation
  generates a name like "Task-1" using a monotonic counter.

* bpo-34263: asyncio's event loop will not pass timeouts longer than
  one day to epoll/select etc.

* bpo-34035: Fix several AttributeError in zipfile seek() methods.
  Patch by Mickaël Schoentgen.

* bpo-32215: Fix performance regression in "sqlite3" when a DML
  statement appeared in a different line than the rest of the SQL
  query.

* bpo-34075: Deprecate passing non-ThreadPoolExecutor instances to
  "AbstractEventLoop.set_default_executor()".

* bpo-34251: Restore "msilib.Win64" to preserve backwards
  compatibility since it's already used by "distutils"' "bdist_msi"
  command.

* bpo-19891: Ignore errors caused by missing / non-writable homedir
  while writing history during exit of an interactive session.  Patch
  by Anthony Sottile.

* bpo-33089: Enhanced math.hypot() to support more than two
  dimensions.

* bpo-34228: tracemalloc: PYTHONTRACEMALLOC=0 environment variable
  and -X tracemalloc=0 command line option are now allowed to disable
  explicitly tracemalloc at startup.

* bpo-13041: Use "shutil.get_terminal_size()" to calculate the
  terminal width correctly in the "argparse.HelpFormatter" class.
  Initial patch by Zbyszek Jędrzejewski-Szmek.

* bpo-34213: Allow frozen dataclasses to have a field named
  "object". Previously this conflicted with an internal use of
  "object".

* bpo-34052: "sqlite3.Connection.create_aggregate()",
  "sqlite3.Connection.create_function()",
  "sqlite3.Connection.set_authorizer()",
  "sqlite3.Connection.set_progress_handler()" methods raises TypeError
  when unhashable objects are passed as callable. These methods now
  don't pass such objects to SQLite API. Previous behavior could lead
  to segfaults. Patch by Sergey Fedoseev.

* bpo-34197: Attributes *skipinitialspace*, *doublequote* and
  *strict* of the *dialect* attribute of the "csv" reader are now
  "bool" instances instead of integers 0 or 1.

* bpo-32788: Errors other than "TypeError" raised in methods
  "__adapt__()" and "__conform__()" in the "sqlite3" module are now
  propagated to the user.

* bpo-21446: The "reload" fixer now uses "importlib.reload()"
  instead of deprecated "imp.reload()".

* bpo-940286: pydoc's "Helper.showtopic()" method now prints the
  cross references of a topic correctly.

* bpo-34164: "base64.b32decode()" could raise UnboundLocalError or
  OverflowError for incorrect padding.  Now it always raises
  "base64.Error" in these cases.

* bpo-33729: Fixed issues with arguments parsing in "hashlib".

* bpo-34097: ZipFile can zip files older than 1980-01-01 and newer
  than 2107-12-31 using a new "strict_timestamps" parameter at the
  cost of setting the timestamp to the limit.

* bpo-34108: Remove extraneous CR in 2to3 refactor.

* bpo-34070: Make sure to only check if the handle is a tty, when
  opening a file with "buffering=-1".

* bpo-27494: Reverted bpo-27494. 2to3 rejects now a trailing comma
  in generator expressions.

* bpo-33967: functools.singledispatch now raises TypeError instead
  of IndexError when no positional arguments are passed.

* bpo-34041: Add the parameter *deterministic* to the
  "sqlite3.Connection.create_function()" method. Patch by Sergey
  Fedoseev.

* bpo-34056: Ensure the loader shim created by "imp.load_module"
  always returns bytes from its "get_data()" function. This fixes
  using "imp.load_module" with **PEP 552** hash-based pycs.

* bpo-34054: The multiprocessing module now uses the monotonic clock
  "time.monotonic()" instead of the system clock "time.time()" to
  implement timeout.

* bpo-34043: Optimize tarfile uncompress performance about 15% when
  gzip is used.

* bpo-34044: "subprocess.Popen" now copies the *startupinfo*
  argument to leave it unchanged: it will modify the copy, so that the
  same "STARTUPINFO" object can be used multiple times.

* bpo-34010: Fixed a performance regression for reading streams with
  tarfile. The buffered read should use a list, instead of appending
  to a bytes object.

* bpo-34019: webbrowser: Correct the arguments passed to Opera
  Browser when opening a new URL using the "webbrowser" module. Patch
  by Bumsik Kim.

* bpo-34003: csv.DictReader now creates dicts instead of
  OrderedDicts. Patch by Michael Selik.

* bpo-33978: Closed existing logging handlers before reconfiguration
  via fileConfig and dictConfig. Patch by Karthikeyan Singaravelan.

* bpo-14117: Make minor tweaks to turtledemo. The 'wikipedia'
  example is now 'rosette', describing what it draws.  The 'penrose'
  print output is reduced. The'1024' output of 'tree' is eliminated.

* bpo-33974: Fixed passing lists and tuples of strings containing
  special characters """, "\", "{", "}" and "\n" as options to "ttk"
  widgets.

* bpo-27500: Fix getaddrinfo to resolve IPv6 addresses correctly.

* bpo-24567: Improve random.choices() to handle subnormal input
  weights that could occasionally trigger an IndexError.

* bpo-33871: Fixed integer overflow in "os.readv()", "os.writev()",
  "os.preadv()" and "os.pwritev()" and in "os.sendfile()" with
  *headers* or *trailers* arguments (on BSD-based OSes and macOS).

* bpo-25007: Add "copy.copy()" and "copy.deepcopy()" support to zlib
  compressors and decompressors.  Patch by Zackery Spytz.

* bpo-33929: multiprocessing: Fix a race condition in Popen of
  multiprocessing.popen_spawn_win32. The child process now duplicates
  the read end of pipe instead of "stealing" it. Previously, the read
  end of pipe was "stolen" by the child process, but it leaked a
  handle if the child process had been terminated before it could
  steal the handle from the parent process.

* bpo-33899: Tokenize module now implicitly emits a NEWLINE when
  provided with input that does not have a trailing new line.  This
  behavior now matches what the C tokenizer does internally.
  Contributed by Ammar Askar.

* bpo-33897: Added a 'force' keyword argument to
  logging.basicConfig().

* bpo-33695: "shutil.copytree()" uses "os.scandir()" function and
  all copy functions depending from it use cached "os.stat()" values.
  The speedup for copying a directory with 8000 files is around +9% on
  Linux, +20% on Windows and + 30% on a Windows SMB share. Also the
  number of "os.stat()" syscalls is reduced by 38% making
  "shutil.copytree()" especially faster on network filesystems.
  (Contributed by Giampaolo Rodola' in bpo-33695.)

* bpo-33916: bz2 and lzma: When Decompressor.__init__() is called
  twice, free the old lock to not leak memory.

* bpo-32568: Make select.epoll() and its documentation consistent
  regarding *sizehint* and *flags*.

* bpo-33833: Fixed bug in asyncio where ProactorSocketTransport logs
  AssertionError if force closed during write.

* bpo-33663: Convert content length to string before putting to
  header.

* bpo-33721: "os.path" functions that return a boolean result like
  "exists()", "lexists()", "isdir()", "isfile()", "islink()", and
  "ismount()", and "pathlib.Path" methods that return a boolean result
  like "exists()", "is_dir()", "is_file()", "is_mount()",
  "is_symlink()", "is_block_device()", "is_char_device()",
  "is_fifo()", "is_socket()" now return "False" instead of raising
  "ValueError" or its subclasses "UnicodeEncodeError" and
  "UnicodeDecodeError" for paths that contain characters or bytes
  unrepresentable at the OS level.

* bpo-26544: Fixed implementation of "platform.libc_ver()". It
  almost always returned version '2.9' for glibc.

* bpo-33843: Remove deprecated "cgi.escape", "cgi.parse_qs" and
  "cgi.parse_qsl".

* bpo-33842: Remove "tarfile.filemode" which is deprecated since
  Python 3.3.

* bpo-30167: Prevent site.main() exception if PYTHONSTARTUP is set.
  Patch by Steve Weber.

* bpo-33805: Improve error message of dataclasses.replace() when an
  InitVar is not specified

* bpo-33687: Fix the call to "os.chmod()" for "uu.decode()" if a
  mode is given or decoded. Patch by Timo Furrer.

* bpo-33812: Datetime instance d with non-None tzinfo, but with
  d.tzinfo.utcoffset(d) returning None is now treated as naive by the
  astimezone() method.

* bpo-32108: In configparser, don't clear section when it is
  assigned to itself.

* bpo-27397: Make email module properly handle invalid-length base64
  strings.

* bpo-33578: Implement multibyte encoder/decoder state methods

* bpo-30805: Avoid race condition with debug logging

* bpo-33476: Fix _header_value_parser.py when address group is
  missing final ';'. Contributed by Enrique Perez-Terron

* bpo-33694: asyncio: Fix a race condition causing data loss on
  pause_reading()/resume_reading() when using the ProactorEventLoop.

* bpo-32493: Correct test for "uuid_enc_be" availability in
  "configure.ac". Patch by Michael Felt.

* bpo-33792: Add asyncio.WindowsSelectorEventLoopPolicy and
  asyncio.WindowsProactorEventLoopPolicy.

* bpo-33274: W3C DOM Level 1 specifies return value of
  Element.removeAttributeNode() as "The Attr node that was removed."
  xml.dom.minidom now complies with this requirement.

* bpo-33778: Update "unicodedata"'s database to Unicode version
  11.0.0.

* bpo-33165: Added a stacklevel parameter to logging calls to allow
  use of wrapper/helper functions for logging APIs.

* bpo-33770: improve base64 exception message for encoded inputs of
  invalid length

* bpo-33769: asyncio/start_tls: Fix error message; cancel callbacks
  in case of an unhandled error; mark SSLTransport as closed if it is
  aborted.

* bpo-33767: The concatenation ("+") and repetition ("*") sequence
  operations now raise "TypeError" instead of "SystemError" when
  performed on "mmap.mmap" objects.  Patch by Zackery Spytz.

* bpo-33734: asyncio/ssl: Fix AttributeError, increase default
  handshake timeout

* bpo-31014: Fixed creating a controller for "webbrowser" when a
  user specifies a path to an entry in the BROWSER environment
  variable. Based on patch by John Still.

* bpo-2504: Add gettext.pgettext() and variants.

* bpo-33197: Add description property for _ParameterKind

* bpo-32751: When cancelling the task due to a timeout,
  "asyncio.wait_for()" will now wait until the cancellation is
  complete.

* bpo-32684: Fix gather to propagate cancellation of itself even
  with return_exceptions.

* bpo-33654: Support protocol type switching in
  SSLTransport.set_protocol().

* bpo-33674: Pause the transport as early as possible to further
  reduce the risk of data_received() being called before
  connection_made().

* bpo-33671: "shutil.copyfile()", "shutil.copy()", "shutil.copy2()",
  "shutil.copytree()" and "shutil.move()" use platform-specific fast-
  copy syscalls on Linux and macOS in order to copy the file more
  efficiently. On Windows "shutil.copyfile()" uses a bigger default
  buffer size (1 MiB instead of 16 KiB) and a "memoryview()"-based
  variant of "shutil.copyfileobj()" is used. The speedup for copying a
  512MiB file is about +26% on Linux, +50% on macOS and +40% on
  Windows. Also, much less CPU cycles are consumed. (Contributed by
  Giampaolo Rodola' in bpo-25427.)

* bpo-33674: Fix a race condition in SSLProtocol.connection_made()
  of asyncio.sslproto: start immediately the handshake instead of
  using call_soon(). Previously, data_received() could be called
  before the handshake started, causing the handshake to hang or fail.

* bpo-31647: Fixed bug where calling write_eof() on a
  _SelectorSocketTransport after it's already closed raises
  AttributeError.

* bpo-32610: Make asyncio.all_tasks() return only pending tasks.

* bpo-32410: Avoid blocking on file IO in sendfile fallback code

* bpo-33469: Fix RuntimeError after closing loop that used
  run_in_executor

* bpo-33672: Fix Task.__repr__ crash with Cython's bogus coroutines

* bpo-33654: Fix transport.set_protocol() to support switching
  between asyncio.Protocol and asyncio.BufferedProtocol.  Fix
  loop.start_tls() to work with asyncio.BufferedProtocols.

* bpo-33652: Pickles of type variables and subscripted generics are
  now future-proof and compatible with older Python versions.

* bpo-32493: Fixed "uuid.uuid1()" on FreeBSD.

* bpo-33238: Add "InvalidStateError" to "concurrent.futures".
  "Future.set_result" and "Future.set_exception" now raise
  "InvalidStateError" if the futures are not pending or running. Patch
  by Jason Haydaman.

* bpo-33618: Finalize and document preliminary and experimental TLS
  1.3 support with OpenSSL 1.1.1

* bpo-33625: Release GIL on "grp.getgrnam", "grp.getgrgid",
  "pwd.getpwnam" and "pwd.getpwuid" if reentrant variants of these
  functions are available. Patch by William Grzybowski.

* bpo-33623: Fix possible SIGSGV when asyncio.Future is created in
  __del__

* bpo-11874: Use a better regex when breaking usage into wrappable
  parts. Avoids bogus assertion errors from custom metavar strings.

* bpo-30877: Fixed a bug in the Python implementation of the JSON
  decoder that prevented the cache of parsed strings from clearing
  after finishing the decoding. Based on patch by c-fos.

* bpo-33604: Remove HMAC default to md5 marked for removal in 3.8
  (removal originally planned in 3.6, bump to 3.8 in gh-7062).

* bpo-33582: Emit a deprecation warning for inspect.formatargspec

* bpo-21145: Add "functools.cached_property" decorator, for computed
  properties cached for the life of the instance.

* bpo-33570: Change TLS 1.3 cipher suite settings for compatibility
  with OpenSSL 1.1.1-pre6 and newer. OpenSSL 1.1.1 will have TLS 1.3
  ciphers enabled by default.

* bpo-28556: Do not simplify arguments to "typing.Union". Now
  "Union[Manager, Employee]" is not simplified to "Employee" at
  runtime. Such simplification previously caused several bugs and
  limited possibilities for introspection.

* bpo-12486: "tokenize.generate_tokens()" is now documented as a
  public API to tokenize unicode strings. It was previously present
  but undocumented.

* bpo-33540: Add a new "block_on_close" class attribute to
  "ForkingMixIn" and "ThreadingMixIn" classes of "socketserver".

* bpo-33548: tempfile._candidate_tempdir_list should consider common
  TEMP locations

* bpo-33109: argparse subparsers are once again not required by
  default, reverting the change in behavior introduced by bpo-26510 in
  3.7.0a2.

* bpo-33541: Remove unused private method
  "_strptime.LocaleTime.__pad" (a.k.a. "_LocaleTime__pad").

* bpo-33536: dataclasses.make_dataclass now checks for invalid field
  names and duplicate fields. Also, added a check for invalid field
  specifications.

* bpo-33542: Prevent "uuid.get_node" from using a DUID instead of a
  MAC on Windows. Patch by Zvi Effron

* bpo-26819: Fix race condition with "ReadTransport.resume_reading"
  in Windows proactor event loop.

* Fix failure in "typing.get_type_hints()" when ClassVar was
  provided as a string forward reference.

* bpo-33516: "unittest.mock.MagicMock" now supports the "__round__"
  magic method.

* bpo-28612: Added support for Site Maps to urllib's
  "RobotFileParser" as "RobotFileParser.site_maps()". Patch by Lady
  Red, based on patch by Peter Wirtz.

* bpo-28167: Remove platform.linux_distribution, which was
  deprecated since 3.5.

* bpo-33504: Switch the default dictionary implementation for
  "configparser" from "collections.OrderedDict" to the standard "dict"
  type.

* bpo-33505: Optimize asyncio.ensure_future() by reordering if
  checks: 1.17x faster.

* bpo-33497: Add errors param to cgi.parse_multipart and make an
  encoding in FieldStorage use the given errors (needed for Twisted).
  Patch by Amber Brown.

* bpo-29235: The "cProfile.Profile" class can now be used as a
  context manager. Patch by Scott Sanderson.

* bpo-33495: Change dataclasses.Fields repr to use the repr of each
  of its members, instead of str.  This makes it more clear what each
  field actually represents.  This is especially true for the 'type'
  member.

* bpo-26103: Correct "inspect.isdatadescriptor" to look for
  "__set__" or "__delete__".  Patch by Aaron Hall.

* bpo-29209: Removed the "doctype()" method and the *html* parameter
  of the constructor of "XMLParser".  The "doctype()" method defined
  in a subclass will no longer be called. Deprecated methods
  "getchildren()" and "getiterator()" in the "ElementTree" module emit
  now a "DeprecationWarning" instead of "PendingDeprecationWarning".

* bpo-33453: Fix dataclasses to work if using literal string type
  annotations or if using PEP 563 "Postponed Evaluation of
  Annotations". Only specific string prefixes are detected for both
  ClassVar ("ClassVar" and "typing.ClassVar") and InitVar ("InitVar"
  and "dataclasses.InitVar").

* bpo-28556: Minor fixes in typing module: add annotations to
  "NamedTuple.__new__", pass "*args" and "**kwds" in
  "Generic.__new__".  Original PRs by Paulius Šarka and Chad Dombrova.

* bpo-33365: Print the header values besides the header keys instead
  just the header keys if *debuglevel* is set to >0 in "http.client".
  Patch by Marco Strigl.

* bpo-20087: Updated alias mapping with glibc 2.27 supported
  locales.

* bpo-33422: Fix trailing quotation marks getting deleted when
  looking up byte/string literals on pydoc. Patch by Andrés Delfino.

* bpo-28167: The function "platform.linux_distribution" and
  "platform.dist" now trigger a "DeprecationWarning" and have been
  marked for removal in Python 3.8

* bpo-33281: Fix ctypes.util.find_library regression on macOS.

* bpo-33311: Text and html output generated by cgitb does not
  display parentheses if the current call is done directly in the
  module. Patch by Stéphane Blondon.

* bpo-27300: The file classes in *tempfile* now accept an *errors*
  parameter that complements the already existing *encoding*.  Patch
  by Stephan Hohe.

* bpo-32933: "unittest.mock.mock_open()" now supports iteration over
  the file contents. Patch by Tony Flury.

* bpo-33217: Raise "TypeError" when looking up non-Enum objects in
  Enum classes and Enum members.

* bpo-33197: Update error message when constructing invalid
  inspect.Parameters Patch by Dong-hee Na.

* bpo-33383: Fixed crash in the get() method of the "dbm.ndbm"
  database object when it is called with a single argument.

* bpo-33375: The warnings module now finds the Python file
  associated with a warning from the code object, rather than the
  frame's global namespace. This is consistent with how tracebacks and
  pdb find filenames, and should work better for dynamically executed
  code.

* bpo-33336: "imaplib" now allows "MOVE" command in "IMAP4.uid()"
  (RFC 6851: IMAP MOVE Extension) and potentially as a name of
  supported method of "IMAP4" object.

* bpo-32455: Added *jump* parameter to "dis.stack_effect()".

* bpo-27485: Rename and deprecate undocumented functions in
  "urllib.parse()".

* bpo-33332: Add "signal.valid_signals()" to expose the POSIX
  sigfillset() functionality.

* bpo-33251: "ConfigParser.items()" was fixed so that key-value
  pairs passed in via "vars" are not included in the resulting output.

* bpo-33329: Fix multiprocessing regression on newer glibcs

* bpo-33334: "dis.stack_effect()" now supports all defined opcodes
  including NOP and EXTENDED_ARG.

* bpo-991266: Fix quoting of the "Comment" attribute of
  "http.cookies.SimpleCookie".

* bpo-33131: Upgrade bundled version of pip to 10.0.1.

* bpo-33308: Fixed a crash in the "parser" module when converting an
  ST object to a tree of tuples or lists with "line_info=False" and
  "col_info=True".

* bpo-23403: lib2to3 now uses pickle protocol 4 for pre-computed
  grammars.

* bpo-33266: lib2to3 now recognizes "rf'...'" strings.

* bpo-11594: Ensure line-endings are respected when using lib2to3.

* bpo-33254: Have "importlib.resources.contents()" and
  "importlib.abc.ResourceReader.contents()" return an *iterable*
  instead of an *iterator*.

* bpo-33265: "contextlib.ExitStack" and "contextlib.AsyncExitStack"
  now use a method instead of a wrapper function for exit callbacks.

* bpo-33263: Fix FD leak in "_SelectorSocketTransport"  Patch by
  Vlad Starostin.

* bpo-33256: Fix display of "<module>" call in the html produced by
  "cgitb.html()". Patch by Stéphane Blondon.

* bpo-33144: "random.Random()" and its subclassing mechanism got
  optimized to check only once at class/subclass instantiation time
  whether its "getrandbits()" method can be relied on by other
  methods, including "randrange()", for the generation of arbitrarily
  large random integers. Patch by Wolfgang Maier.

* bpo-33185: Fixed regression when running pydoc with the "-m"
  switch. (The regression was introduced in 3.7.0b3 by the resolution
  of bpo-33053)

  This fix also changed pydoc to add "os.getcwd()" to "sys.path" when
  necessary, rather than adding ""."".

* bpo-29613: Added support for the "SameSite" cookie flag to the
  "http.cookies" module.

* bpo-33169: Delete entries of "None" in "sys.path_importer_cache"
  when "importlib.machinery.invalidate_caches()" is called.

* bpo-33203: "random.Random.choice()" now raises "IndexError" for
  empty sequences consistently even when called from subclasses
  without a "getrandbits()" implementation.

* bpo-33224: Update difflib.mdiff() for **PEP 479**.  Convert an
  uncaught StopIteration in a generator into a return-statement.

* bpo-33209: End framing at the end of C implementation of
  "pickle.Pickler.dump()".

* bpo-32861: The urllib.robotparser's "__str__" representation now
  includes wildcard entries and the "Crawl-delay" and "Request-rate"
  fields. Also removes extra newlines that were being appended to the
  end of the string. Patch by Michael Lazar.

* bpo-23403: "DEFAULT_PROTOCOL" in "pickle" was bumped to 4.
  Protocol 4 is described in **PEP 3154** and available since Python
  3.4. It offers better performance and smaller size compared to
  protocol 3 introduced in Python 3.0.

* bpo-20104: Improved error handling and fixed a reference leak in
  "os.posix_spawn()".

* bpo-33106: Deleting a key from a read-only dbm database raises
  module specific error instead of KeyError.

* bpo-33175: In dataclasses, Field.__set_name__ now looks up the
  __set_name__ special method on the class, not the instance, of the
  default value.

* bpo-32380: Create functools.singledispatchmethod to support
  generic single dispatch on descriptors and methods.

* bpo-33141: Have Field objects pass through __set_name__ to their
  default values, if they have their own __set_name__.

* bpo-33096: Allow ttk.Treeview.insert to insert iid that has a
  false boolean value. Note iid=0 and iid=False would be same. Patch
  by Garvit Khatri.

* bpo-32873: Treat type variables and special typing forms as
  immutable by copy and pickle.  This fixes several minor issues and
  inconsistencies, and improves backwards compatibility with Python
  3.6.

* bpo-33134: When computing dataclass's __hash__, use the lookup
  table to contain the function which returns the __hash__ value.
  This is an improvement over looking up a string, and then testing
  that string to see what to do.

* bpo-33127: ssl模块现在使用LibreSSL 2.7.1编译。

* bpo-32505: 如果数据类的成员变量的类型为Field，但没有类型注解，则引
  发 TypeError。

* bpo-33078: 修复在OSX平台因为依赖sem_getvalue而导致的失败。

* bpo-33116: 将'Field'添加到dataclasses.__all__。

* bpo-32896: Fix an error where subclassing a dataclass with a field
  that uses a default_factory would generate an incorrect class.

* bpo-33100: Dataclasses: If a field has a default value that's a
  MemberDescriptorType, then it's from that field being in __slots__,
  not an actual default value.

* bpo-32953: If a non-dataclass inherits from a frozen dataclass,
  allow attributes to be added to the derived class.  Only attributes
  from the frozen dataclass cannot be assigned to.  Require all
  dataclasses in a hierarchy to be either all frozen or all non-
  frozen.

* bpo-33097: Raise RuntimeError when "executor.submit" is called
  during interpreter shutdown.

* bpo-32968: Modulo and floor division involving Fraction and float
  should return float.

* bpo-33061: 添加丢失的 "NoReturn" 到typing.py的 "__all__"

* bpo-33078: Fix the size handling in multiprocessing.Queue when a
  pickling error occurs.

* bpo-33064: lib2to3 now properly supports trailing commas after
  "*args" and "**kwargs" in function signatures.

* bpo-33056: FIX properly close leaking fds in
  concurrent.futures.ProcessPoolExecutor.

* bpo-33021: Release the GIL during fstat() calls, avoiding hang of
  all threads when calling mmap.mmap(), os.urandom(), and
  random.seed().  Patch by Nir Soffer.

* bpo-31804: Avoid failing in multiprocessing.Process if the
  standard streams are closed or None at exit.

* bpo-33034: Providing an explicit error message when casting the
  port property to anything that is not an integer value using
  "urlparse()" and "urlsplit()". Patch by Matt Eaton.

* bpo-30249: Improve struct.unpack_from() exception messages for
  problems with the buffer size and offset.

* bpo-33037: Skip sending/receiving data after SSL transport
  closing.

* bpo-27683: Fix a regression in "ipaddress" that result of
  "hosts()" is empty when the network is constructed by a tuple
  containing an integer mask and only 1 bit left for addresses.

* bpo-22674: Add the strsignal() function in the signal module that
  returns the system description of the given signal, as returned by
  strsignal(3).

* bpo-32999: Fix C implementation of "ABC.__subclasscheck__(cls,
  subclass)" crashed when "subclass" is not a type object.

* bpo-33009: Fix inspect.signature() for single-parameter
  partialmethods.

* bpo-32969: Expose several missing constants in zlib and fix
  corresponding documentation.

* bpo-32056: Improved exceptions raised for invalid number of
  channels and sample width when read an audio file in modules "aifc",
  "wave" and "sunau".

* bpo-32970: Improved disassembly of the MAKE_FUNCTION instruction.

* bpo-32844: Fix wrong redirection of a low descriptor (0 or 1) to
  stderr in subprocess if another low descriptor is closed.

* bpo-32960: For dataclasses, disallow inheriting frozen from non-
  frozen classes, and also disallow inheriting non-frozen from frozen
  classes. This restriction will be relaxed at a future date.

* bpo-32713: Fixed tarfile.itn handling of out-of-bounds float
  values. Patch by Joffrey Fuhrer.

* bpo-32257: The ssl module now contains OP_NO_RENEGOTIATION
  constant, available with OpenSSL 1.1.0h or 1.1.1.

* bpo-32951: Direct instantiation of SSLSocket and SSLObject objects
  is now prohibited. The constructors were never documented, tested,
  or designed as public constructors. Users were suppose to use
  ssl.wrap_socket() or SSLContext.

* bpo-32929: Remove the tri-state parameter "hash", and add the
  boolean "unsafe_hash". If unsafe_hash is True, add a __hash__
  function, but if a __hash__ exists, raise TypeError.  If unsafe_hash
  is False, add a __hash__ based on the values of eq= and frozen=. The
  unsafe_hash=False behavior is the same as the old hash=None
  behavior.  unsafe_hash=False is the default, just as hash=None used
  to be.

* bpo-32947: Add OP_ENABLE_MIDDLEBOX_COMPAT and test workaround for
  TLSv1.3 for future compatibility with OpenSSL 1.1.1.

* bpo-32146: Document the interaction between frozen executables and
  the spawn and forkserver start methods in multiprocessing.

* bpo-30622: The ssl module now detects missing NPN support in
  LibreSSL.

* bpo-32922: dbm.open() now encodes filename with the filesystem
  encoding rather than default encoding.

* bpo-32759: Free unused arenas in multiprocessing.heap.

* bpo-32859: In "os.dup2", don't check every call whether the "dup3"
  syscall exists or not.

* bpo-32556: nt._getfinalpathname, nt._getvolumepathname and
  nt._getdiskusage now correctly convert from bytes.

* bpo-21060: Rewrite confusing message from setup.py upload from "No
  dist file created in earlier command" to the more helpful "Must
  create and upload files in one command".

* bpo-32857: In "tkinter", "after_cancel(None)" now raises a
  "ValueError" instead of canceling the first scheduled function.
  Patch by Cheryl Sabella.

* bpo-32852: Make sure sys.argv remains as a list when running
  trace.

* bpo-31333: "_abc" module is added.  It is a speedup module with C
  implementations for various functions and methods in "abc". Creating
  an ABC subclass and calling "isinstance" or "issubclass" with an ABC
  subclass are up to 1.5x faster. In addition, this makes Python
  start-up up to 10% faster.

  Note that the new implementation hides internal registry and caches,
  previously accessible via private attributes "_abc_registry",
  "_abc_cache", and "_abc_negative_cache".  There are three debugging
  helper methods that can be used instead "_dump_registry",
  "_abc_registry_clear", and "_abc_caches_clear".

* bpo-32841: Fixed "asyncio.Condition" issue which silently ignored
  cancellation after notifying and cancelling a conditional lock.
  Patch by Bar Harel.

* bpo-32819: ssl.match_hostname() has been simplified and no longer
  depends on re and ipaddress module for wildcard and IP addresses.
  Error reporting for invalid wildcards has been improved.

* bpo-19675: "multiprocessing.Pool" no longer leaks processes if its
  initialization fails.

* bpo-32394: socket: Remove
  TCP_FASTOPEN,TCP_KEEPCNT,TCP_KEEPIDLE,TCP_KEEPINTVL flags on older
  version Windows during run-time.

* bpo-31787: Fixed refleaks of "__init__()" methods in various
  modules. (Contributed by Oren Milman)

* bpo-30157: Fixed guessing quote and delimiter in
  csv.Sniffer.sniff() when only the last field is quoted.  Patch by
  Jake Davis.

* bpo-30688: Added support of "\N{name}" escapes in regular
  expressions. Based on patch by Jonathan Eunice.

* bpo-32792: collections.ChainMap() preserves the order of the
  underlying mappings.

* bpo-32775: "fnmatch.translate()" no longer produces patterns which
  contain set operations. Sets starting with '[' or containing '--',
  '&&', '~~' or '||' will be interpreted differently in regular
  expressions in future versions. Currently they emit warnings.
  fnmatch.translate() now avoids producing patterns containing such
  sets by accident.

* bpo-32622: Implement native fast sendfile for Windows proactor
  event loop.

* bpo-32777: Fix a rare but potential pre-exec child process
  deadlock in subprocess on POSIX systems when marking file
  descriptors inheritable on exec in the child process.  This bug
  appears to have been introduced in 3.4.

* bpo-32647: The ctypes module used to depend on indirect linking
  for dlopen. The shared extension is now explicitly linked against
  libdl on platforms with dl.

* bpo-32749: A "dbm.dumb" database opened with flags 'r' is now
  read- only. "dbm.dumb.open()" with flags 'r' and 'w' no longer
  creates a database if it does not exist.

* bpo-32741: Implement "asyncio.TimerHandle.when()" method.

* bpo-32691: Use mod_spec.parent when running modules with pdb

* bpo-32734: Fixed "asyncio.Lock()" safety issue which allowed
  acquiring and locking the same lock multiple times, without it being
  free. Patch by Bar Harel.

* bpo-32727: Do not include name field in SMTP envelope from
  address. Patch by Stéphane Wirtel

* bpo-31453: Add TLSVersion constants and SSLContext.maximum_version
  / minimum_version attributes. The new API wraps OpenSSL 1.1
  https://w
  ww.openssl.org/docs/man1.1.0/ssl/SSL_CTX_set_min_proto_version.html
  feature.

* bpo-24334: Internal implementation details of ssl module were
  cleaned up. The SSLSocket has one less layer of indirection. Owner
  and session information are now handled by the SSLSocket and
  SSLObject constructor. Channel binding implementation has been
  simplified.

* bpo-31848: Fix the error handling in Aifc_read.initfp() when the
  SSND chunk is not found. Patch by Zackery Spytz.

* bpo-32585: Add Ttk spinbox widget to "tkinter.ttk".  Patch by Alan
  D Moore.

* bpo-32512: "profile" CLI accepts "-m module_name" as an
  alternative to script path.

* bpo-8525: help() on a type now displays builtin subclasses. This
  is intended primarily to help with notification of more specific
  exception subclasses.

  Patch by Sanyam Khurana.

* bpo-31639: http.server now exposes a ThreadingHTTPServer class and
  uses it when the module is run with "-m" to cope with web browsers
  pre-opening sockets.

* bpo-29877: compileall: import ProcessPoolExecutor only when
  needed, preventing hangs on low resource platforms

* bpo-32221: Various functions returning tuple containing IPv6
  addresses now omit "%scope" part since the same information is
  already encoded in *scopeid* tuple item. Especially this speeds up
  "socket.recvfrom()" when it receives multicast packet since useless
  resolving of network interface name is omitted.

* bpo-32147: "binascii.unhexlify()" is now up to 2 times faster.
  Patch by Sergey Fedoseev.

* bpo-30693: The TarFile class now recurses directories in a
  reproducible way.

* bpo-30693: The ZipFile class now recurses directories in a
  reproducible way.

* bpo-31680: Added "curses.ncurses_version".

* bpo-31908: Fix output of cover files for "trace" module command-
  line tool. Previously emitted cover files only when "--missing"
  option was used. Patch by Michael Selik.

* bpo-31608: Raise a "TypeError" instead of crashing if a
  "collections.deque" subclass returns a non-deque from "__new__".
  Patch by Oren Milman.

* bpo-31425: Add support for sockets of the AF_QIPCRTR address
  family, supported by the Linux kernel. This is used to communicate
  with services, such as GPS or radio, running on Qualcomm devices.
  Patch by Bjorn Andersson.

* bpo-22005: Implemented unpickling instances of "datetime", "date"
  and "time" pickled by Python 2. "encoding='latin1'" should be used
  for successful decoding.

* bpo-27645: "sqlite3.Connection" now exposes a "backup" method, if
  the underlying SQLite library is at version 3.6.11 or higher.  Patch
  by Lele Gaifax.

* bpo-16865: Support arrays >=2GiB in "ctypes".  Patch by Segev
  Finer.

* bpo-31508: Removed support of arguments in
  "tkinter.ttk.Treeview.selection". It was deprecated in 3.6.  Use
  specialized methods like "selection_set" for changing the selection.

* bpo-29456: Fix bugs in hangul normalization: u1176, u11a7 and
  u11c3


文档
----

* bpo-21257: Document "http.client.parse_headers()".

* bpo-34764: Improve example of iter() with 2nd sentinel argument.

* bpo-35564: Explicitly set master_doc variable in conf.py for
  compliance with Sphinx 2.0

* bpo-35511: Specified that profile.Profile class doesn't not
  support enable or disable methods. Also, elaborated that Profile
  object as a context manager is only supported in cProfile module.

* bpo-10536: Enhance the gettext docs. Patch by Éric Araujo

* bpo-35089: Remove mention of "typing.io" and "typing.re". Their
  types should be imported from "typing" directly.

* bpo-35038: Fix the documentation about an unexisting
  "f_restricted" attribute in the frame object. Patch by Stéphane
  Wirtel

* bpo-35042: Replace PEP XYZ by the pep role and allow to use the
  direct links to the PEPs.

* bpo-35044: Fix the documentation with the role "exc" for the
  appropriated exception. Patch by Stéphane Wirtel

* bpo-35035: Rename documentation for "email.utils" to
  "email.utils.rst".

* bpo-34967: Use app.add_object_type() instead of the deprecated
  Sphinx function app.description_unit()

* bpo-34913: Add documentation about the new command line interface
  of the gzip module.

* bpo-32174: chm document displays non-ASCII charaters properly on
  some MBCS Windows systems.

* bpo-11233: Create availability directive for documentation.
  Original patch by Georg Brandl.

* bpo-34790: Document how passing coroutines to asyncio.wait() can
  be confusing.

* bpo-34552: Make clear that "==" operator sometimes is equivalent
  to "is". The "<", "<=", ">" and ">=" operators are only defined
  where they make sense.

* bpo-28617: Fixed info in the stdtypes docs concerning the types
  that support membership tests.

* bpo-20177: Migrate datetime.date.fromtimestamp to Argument Clinic.
  Patch by Tim Hoffmann.

* bpo-34065: Fix wrongly written basicConfig documentation markup
  syntax

* bpo-33460: replaced ellipsis with correct error codes in tutorial
  chapter 3.

* bpo-33847: Add '@' operator entry to index.

* bpo-33409: Clarified the relationship between **PEP 538**'s
  PYTHONCOERCECLOCALE and PEP 540's PYTHONUTF8 mode.

* bpo-33197: Add versionadded tag to the documentation of
  ParameterKind.description

* bpo-17045: Improve the C-API doc for PyTypeObject.  This includes
  adding several quick-reference tables and a lot of missing
  slot/typedef entries. The existing entries were also cleaned up with
  a slightly more consistent format.

* bpo-33736: Improve the documentation of
  "asyncio.open_connection()", "asyncio.start_server()" and their UNIX
  socket counterparts.

* bpo-23859: Document that "asyncio.wait()" does not cancel its
  futures on timeout.

* bpo-32436: Document **PEP 567** changes to asyncio.

* bpo-33604: 更新HMAC md5默认报告DeprecationWarning，并将在3.8移除。

* bpo-33594: Document "getargspec", "from_function" and
  "from_builtin" as deprecated in their respective docstring, and
  include version since deprecation in DeprecationWarning message.

* bpo-33503: 修复错误的pypi链接

* bpo-33421: 为``typing.AsyncContextManager``添加缺失的文档。

* bpo-33487: BZ2file now emit a DeprecationWarning when
  buffering=None is passed, the deprecation message and documentation
  also now explicitly state it is deprecated since 3.0.

* bpo-33378: Add Korean language switcher for
  https://docs.python.org/3/

* bpo-33276: Clarify that the "__path__" attribute on modules cannot
  be just any value.

* bpo-33201: Modernize documentation for writing C extension types.

* bpo-33195: Deprecate "Py_UNICODE" usage in "c-api/arg" document.
  "Py_UNICODE" related APIs are deprecated since Python 3.3, but it is
  missed in the document.

* bpo-33126: Document PyBuffer_ToContiguous().

* bpo-27212: Modify documentation for the "islice()" recipe to
  consume initial values up to the start index.

* bpo-28247: Update "zipapp" documentation to describe how to make
  standalone applications.

* bpo-18802: Documentation changes for ipaddress.  Patch by Jon
  Foster and Berker Peksag.

* bpo-27428: Update documentation to clarify that
  "WindowsRegistryFinder" implements "MetaPathFinder". (Patch by
  Himanshu Lakhara)

* bpo-28124: The ssl module function ssl.wrap_socket() has been de-
  emphasized and deprecated in favor of the more secure and efficient
  SSLContext.wrap_socket() method.

* bpo-17232: Clarify docs for -O and -OO.  Patch by Terry Reedy.

* bpo-32436: Add documentation for the contextvars module (PEP 567).

* bpo-32800: Update link to w3c doc for xml default namespaces.

* bpo-11015: Update "test.support" documentation.

* bpo-32613: Update the faq/windows.html to use the py command from
  PEP 397 instead of python.

* bpo-8722: Document "__getattr__()" behavior when property "get()"
  method raises "AttributeError".

* bpo-32614: Modify RE examples in documentation to use raw strings
  to prevent "DeprecationWarning" and add text to REGEX HOWTO to
  highlight the deprecation.

* bpo-20709: Remove the paragraph where we explain that os.utime()
  does not support a directory as path under Windows. Patch by Jan-
  Philip Gehrcke

* bpo-32722: Remove the bad example in the tutorial of the Generator
  Expression. Patch by Stéphane Wirtel

* bpo-31972: Improve docstrings for "pathlib.PurePath" subclasses.

* bpo-30607: Use the externalized "python-docs-theme" package when
  building the documentation.

* bpo-8243: Add a note about curses.addch and curses.addstr
  exception behavior when writing outside a window, or pad.

* bpo-32337: Update documentation related with "dict" order.

* bpo-25041: Document "AF_PACKET" in the "socket" module.

* bpo-31432: Clarify meaning of CERT_NONE, CERT_OPTIONAL, and
  CERT_REQUIRED flags for ssl.SSLContext.verify_mode.


测试
----

* bpo-35772: Fix sparse file tests of test_tarfile on ppc64 with the
  tmpfs filesystem. Fix the function testing if the filesystem
  supports sparse files: create a file which contains data and
  "holes", instead of creating a file which contains no data. tmpfs
  effective block size is a page size (tmpfs lives in the page cache).
  RHEL uses 64 KiB pages on aarch64, ppc64, ppc64le, only s390x and
  x86_64 use 4 KiB pages, whereas the test punch holes of 4 KiB.

* bpo-35045: Make ssl tests less strict and also accept TLSv1 as
  system default. The changes unbreaks test_min_max_version on Fedora
  29.

* bpo-32710: "test_asyncio/test_sendfile.py" now resets the event
  loop policy using "tearDownModule()" as done in other tests, to
  prevent a warning when running tests on Windows.

* bpo-33717: test.pythoninfo now logs information of all clocks, not
  only time.time() and time.perf_counter().

* bpo-35488: Add a test to pathlib's Path.match() to verify it does
  not support glob-style ** recursive pattern matching.

* bpo-31731: Fix a race condition in "check_interrupted_write()" of
  test_io: create directly the thread with SIGALRM signal blocked,
  rather than blocking the signal later from the thread. Previously,
  it was possible that the thread gets the signal before the signal is
  blocked.

* bpo-35424: Fix test_multiprocessing_main_handling: use
  "multiprocessing.Pool" with a context manager and then explicitly
  join the pool.

* bpo-35519: Rename "test.bisect" module to "test.bisect_cmd" to
  avoid conflict with "bisect" module when running directly a test
  like "./python Lib/test/test_xmlrpc.py".

* bpo-35513: Replace "time.time()" with "time.monotonic()" in tests
  to measure time delta.

* bpo-34279: "test.support.run_unittest()" no longer raise
  "TestDidNotRun" if the test result contains skipped tests. The
  exception is now only raised if no test have been run and no test
  have been skipped.

* bpo-35412: Add testcase to "test_future4": check unicode literal.

* bpo-26704: 添加了对一个实例方法进行双重修补的测试演示。 补丁作者为
  Anthony Sottile。

* bpo-33725: test_multiprocessing_fork may crash on recent versions
  of macOS.  Until the issue is resolved, skip the test on macOS.

* bpo-35352: Modify test_asyncio to use the certificate set from the
  test directory.

* bpo-35317: Fix "mktime()" overflow error in "test_email": run
  "test_localtime_daylight_true_dst_true()" and
  "test_localtime_daylight_false_dst_true()" with a specific timezone.

* bpo-21263: After several reports that test_gdb does not work
  properly on macOS and since gdb is not shipped by default anymore,
  test_gdb is now skipped on macOS when LLVM Clang has been used to
  compile Python. Patch by Lysandros Nikolaou

* bpo-34279: regrtest issue a warning when no tests have been
  executed in a particular test file. Also, a new final result state
  is issued if no test have been executed across all test files. Patch
  by Pablo Galindo.

* bpo-34962: make docstest in Doc now passes., and is enforced in CI

* bpo-23596: Use argparse for the command line of the gzip module.
  Patch by Antony Lee

* bpo-34537: Fix "test_gdb.test_strings()" when "LC_ALL=C" and GDB
  was compiled with Python 3.6 or earlier.

* bpo-34587: test_socket: Remove RDSTest.testCongestion(). The test
  tries to fill the receiver's socket buffer and expects an error. But
  the RDS protocol doesn't require that. Moreover, the Linux
  implementation of RDS expects that the producer of the messages
  reduces its rate, it's not the role of the receiver to trigger an
  error. The test fails on Fedora 28 by design, so just remove it.

* bpo-34661: Fix test_shutil if unzip doesn't support -t.

* bpo-34200: Fixed non-deterministic flakiness of test_pkg by not
  using the scary test.support.module_cleanup() logic to save and
  restore sys.modules contents between test cases.

* bpo-34569: The experimental PEP 554 data channels now correctly
  pass negative PyLong objects between subinterpreters on 32-bit
  systems. Patch by Michael Felt.

* bpo-34594: Fix usage of hardcoded "errno" values in the tests.

* bpo-34579: Fix test_embed for AIX Patch by Michael Felt

* bpo-34542: Use 3072 RSA keys and SHA-256 signature for test certs
  and keys.

* bpo-11193: Remove special condition for AIX in
  "test_subprocess.test_undecodable_env"

* bpo-34347: Fix "test_utf8_mode.test_cmd_line" for AIX

* bpo-34490: On AIX with AF_UNIX family sockets getsockname() does
  not provide 'sockname', so skip calls to
  transport.get_extra_info('sockname')

* bpo-34391: Fix ftplib test for TLS 1.3 by reading from data
  socket.

* bpo-11192: Fix "test_socket" on AIX AIX 6.1 and later IPv6 zone id
  supports only supported by inet_pton6_zone() Switch to runtime-based
  platform.system() to establish current platform  rather than build-
  time based sys.platform()

* bpo-34399: Update all RSA keys and DH params to use at least 2048
  bits.

* bpo-34373: Fix "test_mktime" and "test_pthread_getcpuclickid"
  tests for AIX Add range checking for "_PyTime_localtime" for AIX
  Patch by Michael Felt

* bpo-11191: Skip the distutils test 'test_search_cpp' when using
  XLC as compiler patch by aixtools (Michael Felt)

* Improved an error message when mock assert_has_calls fails.

* bpo-33746: Fix test_unittest when run in verbose mode.

* bpo-33901: Fix test_dbm_gnu on macOS with gdbm 1.15: add a larger
  value to make sure that the file size changes.

* bpo-33873: Fix a bug in "regrtest" that caused an extra test to
  run if --huntrleaks/-R was used. Exit with error in case that
  invalid parameters are specified to --huntrleaks/-R (at least one
  warmup run and one repetition must be used).

* bpo-33562: Check that a global asyncio event loop policy is not
  left behind by any tests.

* bpo-33655: 忽略运行在BSD平台的ZFS上时test_posix_fallocate的失败。

* bpo-32962: Fixed test_gdb when Python is compiled with flags -mcet
  -fcf-protection -O0.

* bpo-33358: Fix "test_embed.test_pre_initialization_sys_options()"
  when the interpreter is built with "--enable-shared".

* bpo-32872: Avoid regrtest compatibility issue with namespace
  packages.

* bpo-32517: Fix failing "test_asyncio" on macOS 10.12.2+ due to
  transport of "KqueueSelector" loop was not being closed.

* bpo-32663: Making sure the "SMTPUTF8SimTests" class of tests gets
  run in test_smtplib.py.

* bpo-27643: Test_C test case needs "signed short" bitfields, but
  the IBM XLC compiler (on AIX) does not support this Skip the code
  and test when AIX and XLC are used

  Applicable to Python2-2.7 and later

* bpo-19417: Add test_bdb.py.

* bpo-31809: Add tests to verify connection with secp ECDH curves.


构建
----

* bpo-34691: The _contextvars module is now built into the core
  Python library on Windows.

* bpo-35683: Improved Azure Pipelines build steps and now verifying
  layouts correctly

* bpo-35642: Remove asynciomodule.c from pythoncore.vcxproj

* bpo-35550: Fix incorrect Solaris #ifdef checks to look for __sun
  && __SVR4 instead of sun when compiling.

* bpo-35499: "make profile-opt" no longer replaces "CFLAGS_NODIST"
  with "CFLAGS". It now adds profile-guided optimization (PGO) flags
  to "CFLAGS_NODIST": existing "CFLAGS_NODIST" flags are kept.

* bpo-35257: Avoid leaking the linker flags from Link Time
  Optimizations (LTO) into distutils when compiling C extensions.

* bpo-35351: When building Python with clang and LTO, LTO flags are
  no longer passed into CFLAGS to build third-party C extensions
  through distutils.

* bpo-35139: Fix a compiler error when statically linking "pyexpat"
  in "Modules/Setup".

* bpo-35059: PCbuild: Set InlineFunctionExpansion to
  OnlyExplicitInline ("/Ob1" option) in pyproject.props in Debug mode
  to expand functions marked as inline. This change should make Python
  compiled in Debug mode a little bit faster on Windows.

* bpo-35011: Restores the use of pyexpatns.h to isolate our embedded
  copy of the expat C library so that its symbols do not conflict at
  link or dynamic loading time with an embedding application or other
  extension modules with their own version of libexpat.

* bpo-28015: Have --with-lto works correctly with clang.

* bpo-34765: Update the outdated install-sh file to the latest
  revision from automake v1.16.1

* bpo-34585: Check for floating-point byte order in configure.ac
  using compilation tests instead of executing code, so that these
  checks work in cross-compiled builds.

* bpo-34710: Fixed SSL module build with OpenSSL & pedantic CFLAGS.

* bpo-34582: Add JUnit XML output for regression tests and update
  Azure DevOps builds.

* bpo-34081: Make Sphinx warnings as errors in the Docs Makefile.

* bpo-34555: Fix for case where it was not possible to have both
  "HAVE_LINUX_VM_SOCKETS_H" and "HAVE_SOCKADDR_ALG" be undefined.

* bpo-33015: Fix an undefined behaviour in the pthread
  implementation of "PyThread_start_new_thread()": add a function
  wrapper to always return "NULL".

* bpo-34245: The Python shared library is now installed with write
  permission (mode 0755), which is the standard way of installing such
  libraries.

* bpo-34121: Fix detection of C11 atomic support on clang.

* bpo-32430: Rename Modules/Setup.dist to Modules/Setup, and remove
  the necessity to copy the former manually to the latter when
  updating the local source tree.

* bpo-30345: Add -g to LDFLAGS when compiling with LTO to get debug
  symbols.

* bpo-5755: Move "-Wstrict-prototypes" option to "CFLAGS_NODIST"
  from "OPT". This option emitted annoying warnings when building
  extension modules written in C++.

* bpo-33614: Ensures module definition files for the stable ABI on
  Windows are correctly regenerated.

* bpo-33648: The --with-c-locale-warning configuration flag has been
  removed. It has had no effect for about a year.

* bpo-33522: Enable CI builds on Visual Studio Team Services at
  https://python.visualstudio.com/cpython

* bpo-33512: configure's check for "long double" has been simplified

* bpo-33483: C compiler is now correctly detected from the standard
  environment variables. --without-gcc and --with-icc options have
  been removed.

* bpo-33394: Enable the verbose build for extension modules, when
  GNU make is passed macros on the command line.

* bpo-33393: Update config.guess and config.sub files.

* bpo-33377: Add new triplets for mips r6 and riscv variants (used
  in extension suffixes).

* bpo-32232: By default, modules configured in "Modules/Setup" are
  no longer built with "-DPy_BUILD_CORE". Instead, modules that
  specifically need that preprocessor definition include it in their
  individual entries.

* bpo-33182: The embedding tests can once again be built with clang
  6.0

* bpo-33163: Upgrade pip to 9.0.3 and setuptools to v39.0.1.

* bpo-33012: gcc 8 has added a new warning heuristic to detect
  invalid function casts and a stock python build seems to hit that
  warning quite often.  The most common is the cast of a METH_NOARGS
  function (that uses just one argument) to a PyCFunction. Fix this by
  adding a dummy argument to all functions that implement METH_NOARGS.

* bpo-32898: Fix the python debug build when using COUNT_ALLOCS.

* bpo-29442: Replace optparse with argparse in setup.py


Windows
-------

* bpo-35890: Fix API calling consistency of GetVersionEx and wcstok.

* bpo-32560: The "py" launcher now forwards its "STARTUPINFO"
  structure to child processes.

* bpo-35854: Fix EnvBuilder and --symlinks in venv on Windows

* bpo-35811: Avoid propagating venv settings when launching via
  py.exe

* bpo-35797: Fix default executable used by the multiprocessing
  module

* bpo-35758: Allow building on ARM with MSVC.

* bpo-29734: Fix handle leaks in os.stat on Windows.

* bpo-35596: Use unchecked PYCs for the embeddable distro to avoid
  zipimport restrictions.

* bpo-35596: Fix vcruntime140.dll being added to embeddable distro
  multiple times.

* bpo-35402: Update Windows build to use Tcl and Tk 8.6.9

* bpo-35401: Updates Windows build to OpenSSL 1.1.0j

* bpo-34977: venv on Windows will now use a python.exe redirector
  rather than copying the actual binaries from the base environment.

* bpo-34977: Adds support for building a Windows App Store package

* bpo-35067: Remove _distutils_findvs module and use vswhere.exe
  instead.

* bpo-32557: Allow shutil.disk_usage to take a file path on Windows

* bpo-34770: Fix a possible null pointer dereference in
  pyshellext.cpp.

* bpo-34603: Fix returning structs from functions produced by MSVC

* bpo-34581: Guard MSVC-specific code in socketmodule.c with "#ifdef
  _MSC_VER".

* bpo-34532: Fixes exit code of list version arguments for py.exe.

* bpo-34062: Fixed the '--list' and '--list-paths' arguments for the
  py.exe launcher

* bpo-34225: Ensure INCLUDE and LIB directories do not end with a
  backslash.

* bpo-34011: A suite of code has been changed which copied across
  DLLs and init.tcl from the running Python location into a venv being
  created. These copies are needed only when running from a Python
  source build, and the copying code is now only run when that is the
  case, rather than whenever a venv is created.

* bpo-34006: Revert line length limit for Windows help docs. The
  line- length limit is not needed because the pages appear in a
  separate app rather than on a browser tab.  It can also interact
  badly with the DPI setting.

* bpo-31546: Restore running PyOS_InputHook while waiting for user
  input at the prompt. The restores integration of interactive GUI
  windows (such as Matplotlib figures) with the prompt on Windows.

* bpo-30237: Output error when ReadConsole is canceled by
  CancelSynchronousIo instead of crashing.

* bpo-33895: GIL is released while calling functions that acquire
  Windows loader lock.

* bpo-33720: Reduces maximum marshal recursion depth on release
  builds.

* bpo-29097: Fix bug where "datetime.fromtimestamp()" erroneously
  throws an "OSError" on Windows for values between 0 and 86400. Patch
  by Ammar Askar.

* bpo-33316: PyThread_release_lock always fails

* bpo-33184: Update Windows installer to use OpenSSL 1.1.0h.

* bpo-32890: Fix usage of GetLastError() instead of errno in
  os.execve() and os.truncate().

* bpo-33016: Fix potential use of uninitialized memory in
  nt._getfinalpathname

* bpo-32903: Fix a memory leak in os.chdir() on Windows if the
  current directory is set to a UNC path.

* bpo-32901: Update Tcl and Tk versions to 8.6.8

* bpo-31966: Fixed WindowsConsoleIO.write() for writing empty data.

* bpo-32409: Ensures activate.bat can handle Unicode contents.

* bpo-32457: Improves handling of denormalized executable path when
  launching Python.

* bpo-32370: Use the correct encoding for ipconfig output in the
  uuid module. Patch by Segev Finer.

* bpo-29248: Fix "os.readlink()" on Windows, which was mistakenly
  treating the "PrintNameOffset" field of the reparse data buffer as a
  number of characters instead of bytes. Patch by Craig Holmquist and
  SSE4.

* bpo-1104: Correctly handle string length in
  "msilib.SummaryInfo.GetProperty()" to prevent it from truncating the
  last character.


macOS
-----

* bpo-35401: Update macOS installer to use OpenSSL 1.1.0j.

* bpo-35025: Properly guard the use of the "CLOCK_GETTIME" et al.
  macros in "timemodule" on macOS.

* bpo-24658: On macOS, fix reading from and writing into a file with
  a size larger than 2 GiB.

* bpo-34405: Update to OpenSSL 1.1.0i for macOS installer builds.

* bpo-33635: In macOS stat on some file descriptors (/dev/fd/3 f.e)
  will result in bad file descriptor OSError. Guard against this
  exception was added in is_dir, is_file and similar methods.
  DirEntry.is_dir can also throw this exception so
  _RecursiveWildcardSelector._iterate_directories was also extended
  with the same error ignoring pattern.

* bpo-13631: The .editrc file in user's home directory is now
  processed correctly during the readline initialization through
  editline emulation on macOS.

* bpo-33184: Update macOS installer build to use OpenSSL 1.1.0h.

* bpo-32726: Build and link with private copy of Tcl/Tk 8.6 for the
  macOS 10.6+ installer. The 10.9+ installer variant already does
  this.  This means that the Python 3.7 provided by the python.org
  macOS installers no longer need or use any external versions of
  Tcl/Tk, either system-provided or user-installed, such as ActiveTcl.

* bpo-32901: Update macOS 10.9+ installer to Tcl/Tk 8.6.8.

* bpo-31903: In "_scproxy", drop the GIL when calling into
  "SystemConfiguration" to avoid deadlocks.


IDLE
----

* bpo-35770: IDLE macosx deletes Options => Configure IDLE. It
  previously deleted Window => Zoom Height by mistake. (Zoom Height is
  now on the Options menu).  On Mac, the settings dialog is accessed
  via Preferences on the IDLE menu.

* bpo-35769: Change IDLE's new file name from 'Untitled' to
  'untitled'

* bpo-35660: Fix imports in idlelib.window.

* bpo-35641: 当函数没有文档字符串时正确地格式化 "calltip"。

* bpo-33987: Use ttk Frame for ttk widgets.

* bpo-34055: Fix erroneous 'smart' indents and newlines in IDLE
  Shell.

* bpo-35591: Find Selection now works when selection not found.

* bpo-35196: Speed up squeezer line counting.

* bpo-35598: Update config_key: use PEP 8 names and ttk widgets,
  make some objects global, and add tests.

* bpo-28097: Add Previous/Next History entries to Shell menu.

* bpo-35208: Squeezer now properly counts wrapped lines before
  newlines.

* bpo-35555: Gray out Code Context menu entry when it's not
  applicable.

* bpo-35521: Document the IDLE editor code context feature. Add some
  internal references within the IDLE doc.

* bpo-22703: The Code Context menu label now toggles between
  Show/Hide Code Context. The Zoom Height menu now toggles between
  Zoom/Restore Height. Zoom Height has moved from the Window menu to
  the Options menu.

* bpo-35213: Where appropriate, use 'macOS' in idlelib.

* bpo-34864: On macOS, warn if the system preference "Prefer tabs
  when opening documents" is set to "Always".

* bpo-34864: Document two IDLE on MacOS issues. The System
  Preferences Dock "prefer tabs always" setting disables some IDLE
  features. Menus are a bit different than as described for Windows
  and Linux.

* bpo-35202: Remove unused imports from lib/idlelib

* bpo-33000: Document that IDLE's shell has no line limit. A program
  that runs indefinitely can overfill memory.

* bpo-23220: Explain how IDLE's Shell displays output.

* bpo-35099: Improve the doc about IDLE running user code.   The
  section is renamed from "IDLE -- console differences" is renamed
  "Running user code". It mostly covers the implications of using
  custom sys.stdxxx objects.

* bpo-35097: Add IDLE doc subsection explaining editor windows.
  Topics include opening, title and status bar, .py* extension, and
  running.

* bpo-35093: Document the IDLE document viewer in the IDLE doc. Add
  a paragraph in "Help and preferences", "Help sources" subsection.

* bpo-35088: Update idlelib.help.copy_string docstring. We now use
  git and backporting instead of hg and forward merging.

* bpo-35087: Update idlelib help files for the current doc build.
  The main change is the elimination of chapter-section numbers.

* bpo-34548: Use configured color theme for read-only text views.

* bpo-1529353: Enable "squeezing" of long outputs in the shell, to
  avoid performance degradation and to clean up the history without
  losing it. Squeezed outputs may be copied, viewed in a separate
  window, and "unsqueezed".

* bpo-34047: Fixed mousewheel scrolling direction on macOS.

* bpo-34275: Make IDLE calltips always visible on Mac. Some MacOS-tk
  combinations need .update_idletasks(). Patch by Kevin Walzer.

* bpo-34120: Fix unresponsiveness after closing certain windows and
  dialogs.

* bpo-33975: Avoid small type when running htests. Since part of the
  purpose of human-viewed tests is to determine that widgets look
  right, it is important that they look the same for testing as when
  running IDLE.

* bpo-33905: Add test for idlelib.stackview.StackBrowser.

* bpo-33924: Change mainmenu.menudefs key 'windows' to 'window'.
  Every other menudef key is lowercase version of main menu entry.

* bpo-33906: Rename idlelib.windows as window Match Window on the
  main menu and remove last plural module name.

* bpo-33917: Fix and document idlelib/idle_test/template.py. The
  revised file compiles, runs, and tests OK.  idle_test/README.txt
  explains how to use it to create new IDLE test files.

* bpo-33904: IDLE: In rstrip, rename class RstripExtension as Rstrip

* bpo-33907: For consistency and clarity, rename an IDLE module and
  classes. Module calltips and its class CallTips are now calltip and
  Calltip. In module calltip_w, class CallTip is now CalltipWindow.

* bpo-33856: Add "help" in the welcome message of IDLE

* bpo-33839: IDLE: refactor ToolTip and CallTip and add
  documentation and tests

* bpo-33855: Minimally test all IDLE modules. Add missing files,
  import module, instantiate classes, and check coverage. Check
  existing files.

* bpo-33656: On Windows, add API call saying that tk scales for DPI.
  On Windows 8.1+ or 10, with DPI compatibility properties of the
  Python binary unchanged, and a monitor resolution greater than 96
  DPI, this should make text and lines sharper.  It should otherwise
  have no effect.

* bpo-33768: Clicking on a context line moves that line to the top
  of the editor window.

* bpo-33763: IDLE: Use read-only text widget for code context
  instead of label widget.

* bpo-33664: Scroll IDLE editor text by lines. Previously, the mouse
  wheel and scrollbar slider moved text by a fixed number of pixels,
  resulting in partial lines at the top of the editor box.  The change
  also applies to the shell and grep output windows, but not to read-
  only text views.

* bpo-33679: Enable theme-specific color configuration for Code
  Context. Use the Highlights tab to see the setting for built-in
  themes or add settings to custom themes.

* bpo-33642: Display up to maxlines non-blank lines for Code
  Context. If there is no current context, show a single blank line.

* bpo-33628: IDLE: Cleanup codecontext.py and its test.

* bpo-33564: IDLE's code context now recognizes async as a block
  opener.

* bpo-21474: Update word/identifier definition from ascii to
  unicode. In text and entry boxes, this affects selection by double-
  click, movement left/right by control-left/right, and deletion
  left/right by control-BACKSPACE/DEL.

* bpo-33204: IDLE: consistently color invalid string prefixes. A 'u'
  string prefix cannot be paired with either 'r' or 'f'. Consistently
  color as much of the prefix, starting at the right, as is valid.
  Revise and extend colorizer test.

* bpo-32984: Set "__file__" while running a startup file.  Like
  Python, IDLE optionally runs one startup file in the Shell window
  before presenting the first interactive input prompt.  For IDLE,
  "-s" runs a file named in environmental variable  "IDLESTARTUP" or
  "PYTHONSTARTUP"; "-r file" runs "file".  Python sets "__file__" to
  the startup file name before running the file and unsets it before
  the first prompt.  IDLE now does the same when run normally, without
  the "-n" option.

* bpo-32940: Simplify and rename StringTranslatePseudoMapping in
  pyparse.

* bpo-32916: Change "str" to "code" in pyparse.

* bpo-32905: Remove unused code in pyparse module.

* bpo-32874: Add tests for pyparse.

* bpo-32837: Using the system and place-dependent default encoding
  for open() is a bad idea for IDLE's system and location-independent
  files.

* bpo-32826: Add "encoding=utf-8" to open() in IDLE's
  test_help_about. GUI test test_file_buttons() only looks at initial
  ascii-only lines, but failed on systems where open() defaults to
  'ascii' because readline() internally reads and decodes far enough
  ahead to encounter a non-ascii character in CREDITS.txt.

* bpo-32831: Add docstrings and tests for codecontext.

* bpo-32765: Update configdialog General tab docstring to add new
  widgets to the widget list.


工具/示例
---------

* bpo-35884: Add a benchmark script for timing various ways to
  access variables: "Tools/scripts/var_access_benchmark.py".

* bpo-34989: python-gdb.py now handles errors on computing the line
  number of a Python frame.

* bpo-20260: Argument Clinic now has non-bitwise unsigned int
  converters.

* bpo-32962: python-gdb now catches "UnicodeDecodeError" exceptions
  when calling "string()".

* bpo-32962: python-gdb now catches ValueError on read_var(): when
  Python has no debug symbols for example.

* bpo-33189: **pygettext.py** now recognizes only literal strings as
  docstrings and translatable strings, and rejects bytes literals and
  f-string expressions.

* bpo-31920: Fixed handling directories as arguments in the
  "pygettext" script. Based on patch by Oleg Krasnikov.

* bpo-29673: Fix pystackv and pystack gdbinit macros.

* bpo-25427: Remove the pyvenv script in favor of "python3 -m venv"
  in order to lower confusion as to what Python interpreter a virtual
  environment will be created for.

* bpo-32885: Add an "-n" flag for "Tools/scripts/pathfix.py" to
  disable automatic backup creation (files with "~" suffix).

* bpo-32222: Fix pygettext not extracting docstrings for functions
  with type annotated arguments. Patch by Toby Harradine.

* bpo-31583: Fix 2to3 for using with --add-suffix option but without
  --output-dir option for relative path to files in current directory.


C API
-----

* bpo-35713: The "PyByteArray_Init()" and "PyByteArray_Fini()"
  functions have been removed. They did nothing since Python 2.7.4 and
  Python 3.2.0, were excluded from the limited API (stable ABI), and
  were not documented.

* bpo-33817: Fixed "_PyBytes_Resize()" for empty bytes objects.

* bpo-35322: Fix memory leak in "PyUnicode_EncodeLocale()" and
  "PyUnicode_EncodeFSDefault()" on error handling.

* bpo-35059: The following C macros have been converted to static
  inline functions: "Py_INCREF()", "Py_DECREF()", "Py_XINCREF()",
  "Py_XDECREF()", "PyObject_INIT()", "PyObject_INIT_VAR()".

* bpo-35296: "make install" now also installs the internal API:
  "Include/internal/*.h" header files.

* bpo-35081: Internal APIs surrounded by "#ifdef Py_BUILD_CORE" have
  been moved from "Include/*.h" headers to new header files
  "Include/internal/pycore_*.h".

* bpo-35259: 基于 Py_LIMITED_API 有条件地声明 "Py_FinalizeEx()" (3.6
  中新增)。 补丁作者 Arthur Neufeld。

* bpo-35081: The "_PyObject_GC_TRACK()" and "_PyObject_GC_UNTRACK()"
  macros have been removed from the public C API.

* bpo-35134: Creation of a new "Include/cpython/" subdirectory.

* bpo-34725: Adds _Py_SetProgramFullPath so embedders may override
  sys.executable

* bpo-34910: Ensure that "PyObject_Print()" always returns "-1" on
  error.  Patch by Zackery Spytz.

* bpo-34523: Py_DecodeLocale() and Py_EncodeLocale() now use the
  UTF-8 encoding on Windows if Py_LegacyWindowsFSEncodingFlag is zero.

* bpo-34193: Fix pluralization in TypeError messages in getargs.c
  and typeobject.c: '1 argument' instead of '1 arguments' and '1
  element' instead of '1 elements'.

* bpo-34127: Return grammatically correct error message based on
  argument count. Patch by Karthikeyan Singaravelan.

* bpo-23927: Fixed "SystemError" in "PyArg_ParseTupleAndKeywords()"
  when the "w*" format unit is used for optional parameter.

* bpo-32455: Added "PyCompile_OpcodeStackEffectWithJump()".

* bpo-34008: Py_Main() can again be called after Py_Initialize(), as
  in Python 3.6.

* bpo-32500: Fixed error messages for "PySequence_Size()",
  "PySequence_GetItem()", "PySequence_SetItem()" and
  "PySequence_DelItem()" called with a mapping and "PyMapping_Size()"
  called with a sequence.

* bpo-33818: "PyExceptionClass_Name()" will now return "const char
  *" instead of "char *".

* bpo-33042: Embedding applications may once again call
  PySys_ResetWarnOptions, PySys_AddWarnOption, and PySys_AddXOption
  prior to calling Py_Initialize.

* bpo-32374: Document that m_traverse for multi-phase initialized
  modules can be called with m_state=NULL, and add a sanity check

* bpo-30863: "PyUnicode_AsWideChar()" and
  "PyUnicode_AsWideCharString()" no longer cache the "wchar_t*"
  representation of string objects.


Python 3.7.0 正式版
===================

*发布日期: 2018-06-27*


库
--

* bpo-33851: Fix "ast.get_docstring()" for a node that lacks a
  docstring.


C API
-----

* bpo-33932: Calling Py_Initialize() twice does nothing, instead of
  failing with a fatal error: restore the Python 3.6 behaviour.


Python 3.7.0 release candidate 1
================================

*发布日期: 2018-06-12*


核心与内置
----------

* bpo-33803: Fix a crash in hamt.c caused by enabling GC tracking
  for an object that hadn't all of its fields set to NULL.

* bpo-33706: Fix a crash in Python initialization when parsing the
  command line options. Thanks Christoph Gohlke for the bug report and
  the fix!

* bpo-30654: Fixed reset of the SIGINT handler to SIG_DFL on
  interpreter shutdown even when there was a custom handler set
  previously. Patch by Philipp Kerling.

* bpo-31849: Fix signed/unsigned comparison warning in pyhash.c.


库
--

* bpo-30167: Prevent site.main() exception if PYTHONSTARTUP is set.
  Patch by Steve Weber.

* bpo-33812: Datetime instance d with non-None tzinfo, but with
  d.tzinfo.utcoffset(d) returning None is now treated as naive by the
  astimezone() method.

* bpo-30805: Avoid race condition with debug logging

* bpo-33694: asyncio: Fix a race condition causing data loss on
  pause_reading()/resume_reading() when using the ProactorEventLoop.

* bpo-32493: Correct test for "uuid_enc_be" availability in
  "configure.ac". Patch by Michael Felt.

* bpo-33792: Add asyncio.WindowsSelectorEventLoopPolicy and
  asyncio.WindowsProactorEventLoopPolicy.

* bpo-33778: Update "unicodedata"'s database to Unicode version
  11.0.0.

* bpo-33770: improve base64 exception message for encoded inputs of
  invalid length

* bpo-33769: asyncio/start_tls: Fix error message; cancel callbacks
  in case of an unhandled error; mark SSLTransport as closed if it is
  aborted.

* bpo-33767: The concatenation ("+") and repetition ("*") sequence
  operations now raise "TypeError" instead of "SystemError" when
  performed on "mmap.mmap" objects.  Patch by Zackery Spytz.

* bpo-33734: asyncio/ssl: Fix AttributeError, increase default
  handshake timeout

* bpo-11874: Use a better regex when breaking usage into wrappable
  parts. Avoids bogus assertion errors from custom metavar strings.

* bpo-33582: Emit a deprecation warning for inspect.formatargspec


文档
----

* bpo-33409: Clarified the relationship between **PEP 538**'s
  PYTHONCOERCECLOCALE and PEP 540's PYTHONUTF8 mode.

* bpo-33736: Improve the documentation of
  "asyncio.open_connection()", "asyncio.start_server()" and their UNIX
  socket counterparts.

* bpo-31432: Clarify meaning of CERT_NONE, CERT_OPTIONAL, and
  CERT_REQUIRED flags for ssl.SSLContext.verify_mode.


构建
----

* bpo-5755: Move "-Wstrict-prototypes" option to "CFLAGS_NODIST"
  from "OPT". This option emitted annoying warnings when building
  extension modules written in C++.


Windows
-------

* bpo-33720: Reduces maximum marshal recursion depth on release
  builds.


IDLE
----

* bpo-33656: On Windows, add API call saying that tk scales for DPI.
  On Windows 8.1+ or 10, with DPI compatibility properties of the
  Python binary unchanged, and a monitor resolution greater than 96
  DPI, this should make text and lines sharper.  It should otherwise
  have no effect.

* bpo-33768: Clicking on a context line moves that line to the top
  of the editor window.

* bpo-33763: IDLE: Use read-only text widget for code context
  instead of label widget.

* bpo-33664: Scroll IDLE editor text by lines. Previously, the mouse
  wheel and scrollbar slider moved text by a fixed number of pixels,
  resulting in partial lines at the top of the editor box.  The change
  also applies to the shell and grep output windows, but not to read-
  only text views.

* bpo-33679: Enable theme-specific color configuration for Code
  Context. Use the Highlights tab to see the setting for built-in
  themes or add settings to custom themes.

* bpo-33642: Display up to maxlines non-blank lines for Code
  Context. If there is no current context, show a single blank line.


Python 3.7.0 beta 5
===================

*发布日期: 2018-05-30*


核心与内置
----------

* bpo-33622: Fixed a leak when the garbage collector fails to add an
  object with the "__del__" method or referenced by it into the
  "gc.garbage" list. "PyGC_Collect()" can now be called when an
  exception is set and preserves it.

* bpo-33509: Fix module_globals parameter of
  warnings.warn_explicit(): don't crash if module_globals is not a
  dict.

* bpo-20104: The new "os.posix_spawn" added in 3.7.0b1 was removed
  as we are still working on what the API should look like.  Expect
  this in 3.8 instead.

* bpo-33475: Fixed miscellaneous bugs in converting annotations to
  strings and optimized parentheses in the string representation.

* bpo-33391: Fix a leak in set_symmetric_difference().

* bpo-28055: Fix unaligned accesses in siphash24(). Patch by Rolf
  Eike Beer.

* bpo-32911: Due to unexpected compatibility issues discovered
  during downstream beta testing, reverted bpo-29463. "docstring"
  field is removed from Module, ClassDef, FunctionDef, and
  AsyncFunctionDef ast nodes which was added in 3.7a1.  Docstring
  expression is restored as a first statement in their body. Based on
  patch by Inada Naoki.

* bpo-21983: Fix a crash in "ctypes.cast()" in case the type
  argument is a ctypes structured data type. Patch by Eryk Sun and
  Oren Milman.


库
--

* bpo-32751: When cancelling the task due to a timeout,
  "asyncio.wait_for()" will now wait until the cancellation is
  complete.

* bpo-32684: Fix gather to propagate cancellation of itself even
  with return_exceptions.

* bpo-33654: Support protocol type switching in
  SSLTransport.set_protocol().

* bpo-33674: Pause the transport as early as possible to further
  reduce the risk of data_received() being called before
  connection_made().

* bpo-33674: Fix a race condition in SSLProtocol.connection_made()
  of asyncio.sslproto: start immediately the handshake instead of
  using call_soon(). Previously, data_received() could be called
  before the handshake started, causing the handshake to hang or fail.

* bpo-31647: Fixed bug where calling write_eof() on a
  _SelectorSocketTransport after it's already closed raises
  AttributeError.

* bpo-32610: Make asyncio.all_tasks() return only pending tasks.

* bpo-32410: Avoid blocking on file IO in sendfile fallback code

* bpo-33469: Fix RuntimeError after closing loop that used
  run_in_executor

* bpo-33672: Fix Task.__repr__ crash with Cython's bogus coroutines

* bpo-33654: Fix transport.set_protocol() to support switching
  between asyncio.Protocol and asyncio.BufferedProtocol.  Fix
  loop.start_tls() to work with asyncio.BufferedProtocols.

* bpo-33652: Pickles of type variables and subscripted generics are
  now future-proof and compatible with older Python versions.

* bpo-32493: Fixed "uuid.uuid1()" on FreeBSD.

* bpo-33618: Finalize and document preliminary and experimental TLS
  1.3 support with OpenSSL 1.1.1

* bpo-33623: Fix possible SIGSGV when asyncio.Future is created in
  __del__

* bpo-30877: Fixed a bug in the Python implementation of the JSON
  decoder that prevented the cache of parsed strings from clearing
  after finishing the decoding. Based on patch by c-fos.

* bpo-33570: Change TLS 1.3 cipher suite settings for compatibility
  with OpenSSL 1.1.1-pre6 and newer. OpenSSL 1.1.1 will have TLS 1.3
  ciphers enabled by default.

* bpo-28556: Do not simplify arguments to "typing.Union". Now
  "Union[Manager, Employee]" is not simplified to "Employee" at
  runtime. Such simplification previously caused several bugs and
  limited possibilities for introspection.

* bpo-33540: Add a new "block_on_close" class attribute to
  "ForkingMixIn" and "ThreadingMixIn" classes of "socketserver".

* bpo-33548: tempfile._candidate_tempdir_list should consider common
  TEMP locations

* bpo-33109: argparse subparsers are once again not required by
  default, reverting the change in behavior introduced by bpo-26510 in
  3.7.0a2.

* bpo-33536: dataclasses.make_dataclass now checks for invalid field
  names and duplicate fields. Also, added a check for invalid field
  specifications.

* bpo-33542: Prevent "uuid.get_node" from using a DUID instead of a
  MAC on Windows. Patch by Zvi Effron

* bpo-26819: Fix race condition with "ReadTransport.resume_reading"
  in Windows proactor event loop.

* Fix failure in "typing.get_type_hints()" when ClassVar was
  provided as a string forward reference.

* bpo-33505: Optimize asyncio.ensure_future() by reordering if
  checks: 1.17x faster.

* bpo-33497: Add errors param to cgi.parse_multipart and make an
  encoding in FieldStorage use the given errors (needed for Twisted).
  Patch by Amber Brown.

* bpo-33495: Change dataclasses.Fields repr to use the repr of each
  of its members, instead of str.  This makes it more clear what each
  field actually represents.  This is especially true for the 'type'
  member.

* bpo-33453: Fix dataclasses to work if using literal string type
  annotations or if using PEP 563 "Postponed Evaluation of
  Annotations". Only specific string prefixes are detected for both
  ClassVar ("ClassVar" and "typing.ClassVar") and InitVar ("InitVar"
  and "dataclasses.InitVar").

* bpo-28556: Minor fixes in typing module: add annotations to
  "NamedTuple.__new__", pass "*args" and "**kwds" in
  "Generic.__new__".  Original PRs by Paulius Šarka and Chad Dombrova.

* bpo-20087: Updated alias mapping with glibc 2.27 supported
  locales.

* bpo-33422: Fix trailing quotation marks getting deleted when
  looking up byte/string literals on pydoc. Patch by Andrés Delfino.

* bpo-28167: The function "platform.linux_distribution" and
  "platform.dist" now trigger a "DeprecationWarning" and have been
  marked for removal in Python 3.8

* bpo-33197: Update error message when constructing invalid
  inspect.Parameters Patch by Dong-hee Na.

* bpo-33263: Fix FD leak in "_SelectorSocketTransport"  Patch by
  Vlad Starostin.

* bpo-32861: The urllib.robotparser's "__str__" representation now
  includes wildcard entries and the "Crawl-delay" and "Request-rate"
  fields. Patch by Michael Lazar.

* bpo-32257: The ssl module now contains OP_NO_RENEGOTIATION
  constant, available with OpenSSL 1.1.0h or 1.1.1.

* bpo-16865: Support arrays >=2GiB in "ctypes".  Patch by Segev
  Finer.


文档
----

* bpo-23859: Document that "asyncio.wait()" does not cancel its
  futures on timeout.

* bpo-32436: Document **PEP 567** changes to asyncio.

* bpo-33604: 更新HMAC md5默认报告DeprecationWarning，并将在3.8移除。

* bpo-33503: 修复错误的pypi链接

* bpo-33421: 为``typing.AsyncContextManager``添加缺失的文档。


测试
----

* bpo-33655: 忽略运行在BSD平台的ZFS上时test_posix_fallocate的失败。

* bpo-32604:  删除_xxsubinterpreters模块（用于测试）和相关的帮助程序
  。 该模块最初最初是在3.7b1中添加的。


构建
----

* bpo-33614: Ensures module definition files for the stable ABI on
  Windows are correctly regenerated.

* bpo-33522: Enable CI builds on Visual Studio Team Services at
  https://python.visualstudio.com/cpython

* bpo-33012: Add "-Wno-cast-function-type" for gcc 8 for silencing
  warnings about function casts like casting to PyCFunction in method
  definition lists.


macOS
-----

* bpo-13631: The .editrc file in user's home directory is now
  processed correctly during the readline initialization through
  editline emulation on macOS.


IDLE
----

* bpo-33628: IDLE: Cleanup codecontext.py and its test.

* bpo-33564: IDLE's code context now recognizes async as a block
  opener.

* bpo-32831: Add docstrings and tests for codecontext.


Python 3.7.0 beta 4
===================

*发布日期: 2018-05-02*


核心与内置
----------

* bpo-33363: 在异步函数外使用``async with`` 和 "async for"  时抛出
  SyntaxError异常。

* bpo-33128: 修复导致PathFinder在sys.meta_path上出现两次的错误。由
  Pablo Galindo Salgado提供补丁。

* bpo-33312: Fixed clang ubsan (undefined behavior sanitizer)
  warnings in dictobject.c by adjusting how the internal struct
  _dictkeysobject shared keys structure is declared.

* bpo-33231: 修复 "normalizestring()" 中潜在的内存泄漏。

* bpo-33205: Change dict growth function from
  "round_up_to_power_2(used*2+hashtable_size/2)" to
  "round_up_to_power_2(used*3)".  Previously, dict is shrinked only
  when "used == 0". Now dict has more chance to be shrinked.

* bpo-29922: Improved error messages in 'async with' when
  "__aenter__()" or "__aexit__()" return non-awaitable object.

* bpo-33199: Fix "ma_version_tag" in dict implementation is
  uninitialized when copying from key-sharing dict.


库
--

* bpo-33281: Fix ctypes.util.find_library regression on macOS.

* bpo-33383: Fixed crash in the get() method of the "dbm.ndbm"
  database object when it is called with a single argument.

* bpo-33329: Fix multiprocessing regression on newer glibcs

* bpo-991266: Fix quoting of the "Comment" attribute of
  "http.cookies.SimpleCookie".

* bpo-33131: Upgrade bundled version of pip to 10.0.1.

* bpo-33308: Fixed a crash in the "parser" module when converting an
  ST object to a tree of tuples or lists with "line_info=False" and
  "col_info=True".

* bpo-33266: lib2to3 now recognizes "rf'...'" strings.

* bpo-11594: Ensure line-endings are respected when using lib2to3.

* bpo-33254: Have "importlib.resources.contents()" and
  "importlib.abc.ResourceReader.contents()" return an *iterable*
  instead of an *iterator*.

* bpo-33256: Fix display of "<module>" call in the html produced by
  "cgitb.html()". Patch by Stéphane Blondon.

* bpo-33185: Fixed regression when running pydoc with the "-m"
  switch. (The regression was introduced in 3.7.0b3 by the resolution
  of bpo-33053) This fix also changed pydoc to add "os.getcwd()" to
  "sys.path" when necessary, rather than adding ""."".

* bpo-33169: Delete entries of "None" in "sys.path_importer_cache"
  when "importlib.machinery.invalidate_caches()" is called.

* bpo-33217: Deprecate looking up non-Enum objects in Enum classes
  and Enum members (will raise "TypeError" in 3.8+).

* bpo-33203: "random.Random.choice()" now raises "IndexError" for
  empty sequences consistently even when called from subclasses
  without a "getrandbits()" implementation.

* bpo-33224: Update difflib.mdiff() for **PEP 479**.  Convert an
  uncaught StopIteration in a generator into a return-statement.

* bpo-33209: End framing at the end of C implementation of
  "pickle.Pickler.dump()".

* bpo-20104: Improved error handling and fixed a reference leak in
  "os.posix_spawn()".

* bpo-33175: In dataclasses, Field.__set_name__ now looks up the
  __set_name__ special method on the class, not the instance, of the
  default value.

* bpo-33097: Raise RuntimeError when "executor.submit" is called
  during interpreter shutdown.

* bpo-31908: Fix output of cover files for "trace" module command-
  line tool. Previously emitted cover files only when "--missing"
  option was used. Patch by Michael Selik.


文档
----

* bpo-33378: Add Korean language switcher for
  https://docs.python.org/3/

* bpo-33276: Clarify that the "__path__" attribute on modules cannot
  be just any value.

* bpo-33201: Modernize documentation for writing C extension types.

* bpo-33195: Deprecate "Py_UNICODE" usage in "c-api/arg" document.
  "Py_UNICODE" related APIs are deprecated since Python 3.3, but it is
  missed in the document.

* bpo-8243: Add a note about curses.addch and curses.addstr
  exception behavior when writing outside a window, or pad.

* bpo-32337: Update documentation related with "dict" order.


测试
----

* bpo-33358: Fix "test_embed.test_pre_initialization_sys_options()"
  when the interpreter is built with "--enable-shared".


构建
----

* bpo-33394: Enable the verbose build for extension modules, when
  GNU make is passed macros on the command line.

* bpo-33393: Update config.guess and config.sub files.

* bpo-33377: Add new triplets for mips r6 and riscv variants (used
  in extension suffixes).

* bpo-32232: By default, modules configured in "Modules/Setup" are
  no longer built with "-DPy_BUILD_CORE". Instead, modules that
  specifically need that preprocessor definition include it in their
  individual entries.

* bpo-33182: The embedding tests can once again be built with clang
  6.0


Windows
-------

* bpo-33184: Update Windows installer to use OpenSSL 1.1.0h.


macOS
-----

* bpo-33184: Update macOS installer build to use OpenSSL 1.1.0h.


IDLE
----

* bpo-21474: Update word/identifier definition from ascii to
  unicode. In text and entry boxes, this affects selection by double-
  click, movement left/right by control-left/right, and deletion
  left/right by control-BACKSPACE/DEL.

* bpo-33204: IDLE: consistently color invalid string prefixes. A 'u'
  string prefix cannot be paired with either 'r' or 'f'. Consistently
  color as much of the prefix, starting at the right, as is valid.
  Revise and extend colorizer test.


工具/示例
---------

* bpo-33189: **pygettext.py** now recognizes only literal strings as
  docstrings and translatable strings, and rejects bytes literals and
  f-string expressions.

* bpo-31920: Fixed handling directories as arguments in the
  "pygettext" script. Based on patch by Oleg Krasnikov.

* bpo-29673: Fix pystackv and pystack gdbinit macros.

* bpo-31583: Fix 2to3 for using with --add-suffix option but without
  --output-dir option for relative path to files in current directory.


Python 3.7.0 beta 3
===================

*发布日期: 2018-03-29*


安全
----

* bpo-33136: Harden ssl module against LibreSSL CVE-2018-8970.
  X509_VERIFY_PARAM_set1_host() is called with an explicit namelen. A
  new test ensures that NULL bytes are not allowed.

* bpo-33001: Minimal fix to prevent buffer overrun in os.symlink on
  Windows

* bpo-32981: Regexes in difflib and poplib were vulnerable to
  catastrophic backtracking. These regexes formed potential DOS
  vectors (REDOS). They have been refactored. This resolves
  CVE-2018-1060 and CVE-2018-1061. Patch by Jamie Davis.


核心与内置
----------

* bpo-33053: When using the -m switch, sys.path[0] is now explicitly
  expanded as the *starting* working directory, rather than being left
  as the empty path (which allows imports from the current working
  directory at the time of the import)

* bpo-33018: Improve consistency of errors raised by "issubclass()"
  when called with a non-class and an abstract base class as the first
  and second arguments, respectively. Patch by Josh Bronson.

* bpo-33041: Fixed jumping when the function contains an "async for"
  loop.

* bpo-33026: Fixed jumping out of "with" block by setting f_lineno.

* bpo-33005: Fix a crash on fork when using a custom memory
  allocator (ex: using PYTHONMALLOC env var). _PyGILState_Reinit() and
  _PyInterpreterState_Enable() now use the default RAW memory
  allocator to allocate a new interpreters mutex on fork.

* bpo-17288: Prevent jumps from 'return' and 'exception' trace
  events.

* bpo-32836: Don't use temporary variables in cases of list/dict/set
  comprehensions


库
--

* bpo-33141: Have Field objects pass through __set_name__ to their
  default values, if they have their own __set_name__.

* bpo-33096: Allow ttk.Treeview.insert to insert iid that has a
  false boolean value. Note iid=0 and iid=False would be same. Patch
  by Garvit Khatri.

* bpo-32873: Treat type variables and special typing forms as
  immutable by copy and pickle.  This fixes several minor issues and
  inconsistencies, and improves backwards compatibility with Python
  3.6.

* bpo-33134: When computing dataclass's __hash__, use the lookup
  table to contain the function which returns the __hash__ value.
  This is an improvement over looking up a string, and then testing
  that string to see what to do.

* bpo-33127: ssl模块现在使用LibreSSL 2.7.1编译。

* bpo-32505: 如果数据类的成员变量的类型为Field，但没有类型注解，则引
  发 TypeError。

* bpo-33078: 修复在OSX平台因为依赖sem_getvalue而导致的失败。

* bpo-33116: 将'Field'添加到dataclasses.__all__。

* bpo-32896: Fix an error where subclassing a dataclass with a field
  that uses a default_factory would generate an incorrect class.

* bpo-33100: Dataclasses: If a field has a default value that's a
  MemberDescriptorType, then it's from that field being in __slots__,
  not an actual default value.

* bpo-32953: If a non-dataclass inherits from a frozen dataclass,
  allow attributes to be added to the derived class.  Only attributes
  from the frozen dataclass cannot be assigned to.  Require all
  dataclasses in a hierarchy to be either all frozen or all non-
  frozen.

* bpo-33061: 添加丢失的 "NoReturn" 到typing.py的 "__all__"

* bpo-33078: Fix the size handling in multiprocessing.Queue when a
  pickling error occurs.

* bpo-33064: lib2to3 now properly supports trailing commas after
  "*args" and "**kwargs" in function signatures.

* bpo-33056: FIX properly close leaking fds in
  concurrent.futures.ProcessPoolExecutor.

* bpo-33021: Release the GIL during fstat() calls, avoiding hang of
  all threads when calling mmap.mmap(), os.urandom(), and
  random.seed().  Patch by Nir Soffer.

* bpo-31804: Avoid failing in multiprocessing.Process if the
  standard streams are closed or None at exit.

* bpo-33037: Skip sending/receiving data after SSL transport
  closing.

* bpo-27683: Fix a regression in "ipaddress" that result of
  "hosts()" is empty when the network is constructed by a tuple
  containing an integer mask and only 1 bit left for addresses.

* bpo-32999: Fix C implementation of "ABC.__subclasscheck__(cls,
  subclass)" crashed when "subclass" is not a type object.

* bpo-33009: Fix inspect.signature() for single-parameter
  partialmethods.

* bpo-32969: Expose several missing constants in zlib and fix
  corresponding documentation.

* bpo-32056: Improved exceptions raised for invalid number of
  channels and sample width when read an audio file in modules "aifc",
  "wave" and "sunau".

* bpo-32844: Fix wrong redirection of a low descriptor (0 or 1) to
  stderr in subprocess if another low descriptor is closed.

* bpo-32857: In "tkinter", "after_cancel(None)" now raises a
  "ValueError" instead of canceling the first scheduled function.
  Patch by Cheryl Sabella.

* bpo-31639: http.server now exposes a ThreadedHTTPServer class and
  uses it when the module is run with "-m" to cope with web browsers
  pre-opening sockets.

* bpo-27645: "sqlite3.Connection" now exposes a "backup" method, if
  the underlying SQLite library is at version 3.6.11 or higher.  Patch
  by Lele Gaifax.


文档
----

* bpo-33126: Document PyBuffer_ToContiguous().

* bpo-27212: Modify documentation for the "islice()" recipe to
  consume initial values up to the start index.

* bpo-28247: Update "zipapp" documentation to describe how to make
  standalone applications.

* bpo-18802: Documentation changes for ipaddress.  Patch by Jon
  Foster and Berker Peksag.

* bpo-27428: Update documentation to clarify that
  "WindowsRegistryFinder" implements "MetaPathFinder". (Patch by
  Himanshu Lakhara)


测试
----

* bpo-32872: Avoid regrtest compatibility issue with namespace
  packages.

* bpo-32517: Fix failing "test_asyncio" on macOS 10.12.2+ due to
  transport of "KqueueSelector" loop was not being closed.

* bpo-19417: Add test_bdb.py.


构建
----

* bpo-33163: Upgrade pip to 9.0.3 and setuptools to v39.0.1.


Windows
-------

* bpo-33016: Fix potential use of uninitialized memory in
  nt._getfinalpathname

* bpo-32903: Fix a memory leak in os.chdir() on Windows if the
  current directory is set to a UNC path.


macOS
-----

* bpo-32726: Build and link with private copy of Tcl/Tk 8.6 for the
  macOS 10.6+ installer. The 10.9+ installer variant already does
  this.  This means that the Python 3.7 provided by the python.org
  macOS installers no longer need or use any external versions of
  Tcl/Tk, either system-provided or user-installed, such as ActiveTcl.


IDLE
----

* bpo-32984: Set "__file__" while running a startup file.  Like
  Python, IDLE optionally runs one startup file in the Shell window
  before presenting the first interactive input prompt.  For IDLE,
  "-s" runs a file named in environmental variable  "IDLESTARTUP" or
  "PYTHONSTARTUP"; "-r file" runs "file".  Python sets "__file__" to
  the startup file name before running the file and unsets it before
  the first prompt.  IDLE now does the same when run normally, without
  the "-n" option.

* bpo-32940: Simplify and rename StringTranslatePseudoMapping in
  pyparse.


工具/示例
---------

* bpo-32885: Add an "-n" flag for "Tools/scripts/pathfix.py" to
  disable automatic backup creation (files with "~" suffix).


C API
-----

* bpo-33042: Embedding applications may once again call
  PySys_ResetWarnOptions, PySys_AddWarnOption, and PySys_AddXOption
  prior to calling Py_Initialize.

* bpo-32374: Document that m_traverse for multi-phase initialized
  modules can be called with m_state=NULL, and add a sanity check


Python 3.7.0 beta 2
===================

*发布日期: 2018-02-27*


安全
----

* bpo-28414: The ssl module now allows users to perform their own
  IDN en/decoding when using SNI.


核心与内置
----------

* bpo-32889: Update Valgrind suppression list to account for the
  rename of "Py_ADDRESS_IN_RANG" to "address_in_range".

* bpo-31356: Remove the new API added in bpo-31356
  (gc.ensure_disabled() context manager).

* bpo-32305: For namespace packages, ensure that both "__file__" and
  "__spec__.origin" are set to None.

* bpo-32303: Make sure "__spec__.loader" matches "__loader__" for
  namespace packages.

* bpo-32711: Fix the warning messages for Python/ast_unparse.c.
  Patch by Stéphane Wirtel

* bpo-32583: Fix possible crashing in builtin Unicode decoders
  caused by write out-of-bound errors when using customized decode
  error handlers.


库
--

* bpo-32960: For dataclasses, disallow inheriting frozen from non-
  frozen classes, and also disallow inheriting non-frozen from frozen
  classes. This restriction will be relaxed at a future date.

* bpo-32713: Fixed tarfile.itn handling of out-of-bounds float
  values. Patch by Joffrey Fuhrer.

* bpo-32951: Direct instantiation of SSLSocket and SSLObject objects
  is now prohibited. The constructors were never documented, tested,
  or designed as public constructors. Users were suppose to use
  ssl.wrap_socket() or SSLContext.

* bpo-32929: Remove the tri-state parameter "hash", and add the
  boolean "unsafe_hash". If unsafe_hash is True, add a __hash__
  function, but if a __hash__ exists, raise TypeError.  If unsafe_hash
  is False, add a __hash__ based on the values of eq= and frozen=. The
  unsafe_hash=False behavior is the same as the old hash=None
  behavior.  unsafe_hash=False is the default, just as hash=None used
  to be.

* bpo-32947: Add OP_ENABLE_MIDDLEBOX_COMPAT and test workaround for
  TLSv1.3 for future compatibility with OpenSSL 1.1.1.

* bpo-30622: The ssl module now detects missing NPN support in
  LibreSSL.

* bpo-32922: dbm.open() now encodes filename with the filesystem
  encoding rather than default encoding.

* bpo-32859: In "os.dup2", don't check every call whether the "dup3"
  syscall exists or not.

* bpo-32556: nt._getfinalpathname, nt._getvolumepathname and
  nt._getdiskusage now correctly convert from bytes.

* bpo-25988: Emit a "DeprecationWarning" when using or importing an
  ABC directly from "collections" rather than from "collections.abc".

* bpo-21060: Rewrite confusing message from setup.py upload from "No
  dist file created in earlier command" to the more helpful "Must
  create and upload files in one command".

* bpo-32852: Make sure sys.argv remains as a list when running
  trace.

* bpo-31333: "_abc" module is added.  It is a speedup module with C
  implementations for various functions and methods in "abc". Creating
  an ABC subclass and calling "isinstance" or "issubclass" with an ABC
  subclass are up to 1.5x faster. In addition, this makes Python
  start-up up to 10% faster. Note that the new implementation hides
  internal registry and caches, previously accessible via private
  attributes "_abc_registry", "_abc_cache", and "_abc_negative_cache".
  There are three debugging helper methods that can be used instead
  "_dump_registry", "_abc_registry_clear", and "_abc_caches_clear".

* bpo-32841: Fixed "asyncio.Condition" issue which silently ignored
  cancellation after notifying and cancelling a conditional lock.
  Patch by Bar Harel.

* bpo-32819: ssl.match_hostname() has been simplified and no longer
  depends on re and ipaddress module for wildcard and IP addresses.
  Error reporting for invalid wildcards has been improved.

* bpo-32394: socket: Remove
  TCP_FASTOPEN,TCP_KEEPCNT,TCP_KEEPIDLE,TCP_KEEPINTVL flags on older
  version Windows during run-time.

* bpo-31787: Fixed refleaks of "__init__()" methods in various
  modules. (Contributed by Oren Milman)

* bpo-30157: Fixed guessing quote and delimiter in
  csv.Sniffer.sniff() when only the last field is quoted.  Patch by
  Jake Davis.

* bpo-32792: collections.ChainMap() preserves the order of the
  underlying mappings.

* bpo-32775: "fnmatch.translate()" no longer produces patterns which
  contain set operations. Sets starting with '[' or containing '--',
  '&&', '~~' or '||' will be interpreted differently in regular
  expressions in future versions. Currently they emit warnings.
  fnmatch.translate() now avoids producing patterns containing such
  sets by accident.

* bpo-32622: Implement native fast sendfile for Windows proactor
  event loop.

* bpo-32777: Fix a rare but potential pre-exec child process
  deadlock in subprocess on POSIX systems when marking file
  descriptors inheritable on exec in the child process.  This bug
  appears to have been introduced in 3.4.

* bpo-32647: The ctypes module used to depend on indirect linking
  for dlopen. The shared extension is now explicitly linked against
  libdl on platforms with dl.

* bpo-32741: Implement "asyncio.TimerHandle.when()" method.

* bpo-32691: Use mod_spec.parent when running modules with pdb

* bpo-32734: Fixed "asyncio.Lock()" safety issue which allowed
  acquiring and locking the same lock multiple times, without it being
  free. Patch by Bar Harel.

* bpo-32727: Do not include name field in SMTP envelope from
  address. Patch by Stéphane Wirtel

* bpo-31453: Add TLSVersion constants and SSLContext.maximum_version
  / minimum_version attributes. The new API wraps OpenSSL 1.1
  https://w
  ww.openssl.org/docs/man1.1.0/ssl/SSL_CTX_set_min_proto_version.html
  feature.

* bpo-24334: Internal implementation details of ssl module were
  cleaned up. The SSLSocket has one less layer of indirection. Owner
  and session information are now handled by the SSLSocket and
  SSLObject constructor. Channel binding implementation has been
  simplified.

* bpo-31848: Fix the error handling in Aifc_read.initfp() when the
  SSND chunk is not found. Patch by Zackery Spytz.

* bpo-32585: Add Ttk spinbox widget to "tkinter.ttk".  Patch by Alan
  D Moore.

* bpo-32221: Various functions returning tuple containing IPv6
  addresses now omit "%scope" part since the same information is
  already encoded in *scopeid* tuple item. Especially this speeds up
  "socket.recvfrom()" when it receives multicast packet since useless
  resolving of network interface name is omitted.

* bpo-30693: The TarFile class now recurses directories in a
  reproducible way.

* bpo-30693: The ZipFile class now recurses directories in a
  reproducible way.


文档
----

* bpo-28124: The ssl module function ssl.wrap_socket() has been de-
  emphasized and deprecated in favor of the more secure and efficient
  SSLContext.wrap_socket() method.

* bpo-17232: Clarify docs for -O and -OO.  Patch by Terry Reedy.

* bpo-32436: Add documentation for the contextvars module (PEP 567).

* bpo-32800: Update link to w3c doc for xml default namespaces.

* bpo-11015: Update "test.support" documentation.

* bpo-8722: Document "__getattr__()" behavior when property "get()"
  method raises "AttributeError".

* bpo-32614: Modify RE examples in documentation to use raw strings
  to prevent "DeprecationWarning" and add text to REGEX HOWTO to
  highlight the deprecation.

* bpo-31972: Improve docstrings for "pathlib.PurePath" subclasses.


测试
----

* bpo-31809: Add tests to verify connection with secp ECDH curves.


构建
----

* bpo-32898: Fix the python debug build when using COUNT_ALLOCS.


Windows
-------

* bpo-32901: Update Tcl and Tk versions to 8.6.8

* bpo-31966: Fixed WindowsConsoleIO.write() for writing empty data.

* bpo-32409: Ensures activate.bat can handle Unicode contents.

* bpo-32457: Improves handling of denormalized executable path when
  launching Python.

* bpo-32370: Use the correct encoding for ipconfig output in the
  uuid module. Patch by Segev Finer.

* bpo-29248: Fix "os.readlink()" on Windows, which was mistakenly
  treating the "PrintNameOffset" field of the reparse data buffer as a
  number of characters instead of bytes. Patch by Craig Holmquist and
  SSE4.


macOS
-----

* bpo-32901: Update macOS 10.9+ installer to Tcl/Tk 8.6.8.


IDLE
----

* bpo-32916: Change "str" to "code" in pyparse.

* bpo-32905: Remove unused code in pyparse module.

* bpo-32874: Add tests for pyparse.

* bpo-32837: Using the system and place-dependent default encoding
  for open() is a bad idea for IDLE's system and location-independent
  files.

* bpo-32826: Add "encoding=utf-8" to open() in IDLE's
  test_help_about. GUI test test_file_buttons() only looks at initial
  ascii-only lines, but failed on systems where open() defaults to
  'ascii' because readline() internally reads and decodes far enough
  ahead to encounter a non-ascii character in CREDITS.txt.

* bpo-32765: Update configdialog General tab docstring to add new
  widgets to the widget list.


工具/示例
---------

* bpo-32222: Fix pygettext not extracting docstrings for functions
  with type annotated arguments. Patch by Toby Harradine.


Python 3.7.0 beta 1
===================

*Release date: 2018-01-30*


核心与内置
----------

* bpo-32703: Fix coroutine's ResourceWarning when there's an active
  error set when it's being finalized.

* bpo-32650: Pdb and other debuggers dependent on bdb.py will
  correctly step over (next command) native coroutines. Patch by Pablo
  Galindo.

* bpo-28685: Optimize list.sort() and sorted() by using type
  specialized comparisons when possible.

* bpo-32685: Improve suggestion when the Python 2 form of print
  statement is either present on the same line as the header of a
  compound statement or else terminated by a semi-colon instead of a
  newline. Patch by Nitish Chandra.

* bpo-32697: Python now explicitly preserves the definition order of
  keyword-only parameters.  It's always preserved their order, but
  this behavior was never guaranteed before; this behavior is now
  guaranteed and tested.

* bpo-32690: The locals() dictionary now displays in the lexical
  order that variables were defined.  Previously, the order was
  reversed.

* bpo-32677: Add ".isascii()" method to "str", "bytes" and
  "bytearray". It can be used to test that string contains only ASCII
  characters.

* bpo-32670: Enforce **PEP 479** for all code. This means that
  manually raising a StopIteration exception from a generator is
  prohibited for all code, regardless of whether 'from __future__
  import generator_stop' was used or not.

* bpo-32591: Added built-in support for tracking the origin of
  coroutine objects; see sys.set_coroutine_origin_tracking_depth and
  CoroutineType.cr_origin. This replaces the asyncio debug mode's use
  of coroutine wrapping for native coroutine objects.

* bpo-31368: Expose preadv and pwritev system calls in the os
  module. Patch by Pablo Galindo

* bpo-32544: "hasattr(obj, name)" and "getattr(obj, name, default)"
  are about 4 times faster than before when "name" is not found and
  "obj" doesn't override "__getattr__" or "__getattribute__".

* bpo-26163: Improved frozenset() hash to create more distinct hash
  values when faced with datasets containing many similar values.

* bpo-32550: Remove the STORE_ANNOTATION bytecode.

* bpo-20104: Expose posix_spawn as a low level API in the os module.
  (removed before 3.7.0rc1)

* bpo-24340: Fixed estimation of the code stack size.

* bpo-32436: Implement **PEP 567** Context Variables.

* bpo-18533: "repr()" on a dict containing its own "values()" or
  "items()" no longer raises "RecursionError"; OrderedDict similarly.
  Instead, use "...", as for other recursive structures.  Patch by Ben
  North.

* bpo-20891: Py_Initialize() now creates the GIL. The GIL is no
  longer created "on demand" to fix a race condition when
  PyGILState_Ensure() is called in a non-Python thread.

* bpo-32028: Leading whitespace is now correctly ignored when
  generating suggestions for converting Py2 print statements to Py3
  builtin print function calls. Patch by Sanyam Khurana.

* bpo-31179: Make dict.copy() up to 5.5 times faster.

* bpo-31113: Get rid of recursion in the compiler for normal control
  flow.


库
--

* bpo-25988: Deprecate exposing the contents of collections.abc in
  the regular collections module.

* bpo-31429: The default cipher suite selection of the ssl module
  now uses a blacklist approach rather than a hard-coded whitelist.
  Python no longer re-enables ciphers that have been blocked by
  OpenSSL security update. Default cipher suite selection can be
  configured on compile time.

* bpo-30306: contextlib.contextmanager now releases the arguments
  passed to the underlying generator as soon as the context manager is
  entered. Previously it would keep them alive for as long as the
  context manager was alive, even when not being used as a function
  decorator. Patch by Martin Teichmann.

* bpo-21417: Added support for setting the compression level for
  zipfile.ZipFile.

* bpo-32251: Implement asyncio.BufferedProtocol (provisional API).

* bpo-32513: In dataclasses, allow easier overriding of dunder
  methods without specifying decorator parameters.

* bpo-32660: "termios" makes available "FIONREAD", "FIONCLEX",
  "FIOCLEX", "FIOASYNC" and "FIONBIO" also under Solaris/derivatives.

* bpo-27931: Fix email address header parsing error when the
  username is an empty quoted string. Patch by Xiang Zhang.

* bpo-32659: Under Solaris and derivatives, "os.stat_result"
  provides a st_fstype attribute.

* bpo-32662: Implement Server.start_serving(),
  Server.serve_forever(), and Server.is_serving() methods.  Add
  'start_serving' keyword parameter to loop.create_server() and
  loop.create_unix_server().

* bpo-32391: Implement "asyncio.StreamWriter.wait_closed()" and
  "asyncio.StreamWriter.is_closing()" methods

* bpo-32643: Make Task._step, Task._wakeup and
  Future._schedule_callbacks methods private.

* bpo-32630: Refactor decimal module to use contextvars to store
  decimal context.

* bpo-32622: Add "asyncio.AbstractEventLoop.sendfile()" method.

* bpo-32304: distutils' upload command no longer corrupts tar files
  ending with a CR byte, and no longer tries to convert CR to CRLF in
  any of the upload text fields.

* bpo-32502: uuid.uuid1 no longer raises an exception if a 64-bit
  hardware address is encountered.

* bpo-32596: "concurrent.futures" imports "ThreadPoolExecutor" and
  "ProcessPoolExecutor" lazily (using **PEP 562**). It makes "import
  asyncio" about 15% faster because asyncio uses only
  "ThreadPoolExecutor" by default.

* bpo-31801: Add "_ignore_" to "Enum" so temporary variables can be
  used during class construction without being turned into members.

* bpo-32576: Use queue.SimpleQueue() in places where it can be
  invoked from a weakref callback.

* bpo-32574: Fix memory leak in asyncio.Queue, when the queue has
  limited size and it is full, the cancelation of queue.put() can
  cause a memory leak. Patch by: José Melero.

* bpo-32521: The nis module is now compatible with new libnsl and
  headers location.

* bpo-32467: collections.abc.ValuesView now inherits from
  collections.abc.Collection.

* bpo-32473: Improve ABCMeta._dump_registry() output readability

* bpo-32102: New argument "capture_output" for subprocess.run

* bpo-32521: glibc has removed Sun RPC. Use replacement libtirpc
  headers and library in nis module.

* bpo-32493: UUID module fixes build for FreeBSD/OpenBSD

* bpo-32503: Pickling with protocol 4 no longer creates too small
  frames.

* bpo-29237: Create enum for pstats sorting options

* bpo-32454: Add close(fd) function to the socket module.

* bpo-25942: The subprocess module is now more graceful when
  handling a Ctrl-C KeyboardInterrupt during subprocess.call,
  subprocess.run, or a Popen context manager.  It now waits a short
  amount of time for the child (presumed to have also gotten the
  SIGINT) to exit, before continuing the KeyboardInterrupt exception
  handling.  This still includes a SIGKILL in the call() and run()
  APIs, but at least the child had a chance first.

* bpo-32433: The hmac module now has hmac.digest(), which provides
  an optimized HMAC digest.

* bpo-28134: Sockets now auto-detect family, type and protocol from
  file descriptor by default.

* bpo-32404: Fix bug where "datetime.datetime.fromtimestamp()" did
  not call __new__ in "datetime.datetime" subclasses.

* bpo-32403: Improved speed of "datetime.date" and
  "datetime.datetime" alternate constructors.

* bpo-32228: Ensure that "truncate()" preserves the file position
  (as reported by "tell()") after writes longer than the buffer size.

* bpo-32410: Implement "loop.sock_sendfile" for asyncio event loop.

* bpo-22908: Added seek and tell to the ZipExtFile class. This only
  works if the file object used to open the zipfile is seekable.

* bpo-32373: Add socket.getblocking() method.

* bpo-32248: Add "importlib.resources" and
  "importlib.abc.ResourceReader" as the unified API for reading
  resources contained within packages.  Loaders wishing to support
  resource reading must implement the "get_resource_reader()" method.
  File-based and zipimport-based loaders both implement these APIs.
  "importlib.abc.ResourceLoader" is deprecated in favor of these new
  APIs.

* bpo-32320: collections.namedtuple() now supports default values.

* bpo-29302: Add contextlib.AsyncExitStack. Patch by Alexander Mohr
  and Ilya Kulakov.

* bpo-31961: *Removed in Python 3.7.0b2.* The *args* argument of
  subprocess.Popen can now be a *path-like object*. If *args* is given
  as a sequence, it's first element can now be a *path-like object* as
  well.

* bpo-31900: The "locale.localeconv()" function now sets temporarily
  the "LC_CTYPE" locale to the "LC_NUMERIC" locale to decode
  "decimal_point" and "thousands_sep" byte strings if they are non-
  ASCII or longer than 1 byte, and the "LC_NUMERIC" locale is
  different than the "LC_CTYPE" locale. This temporary change affects
  other threads. Same change for the "str.format()" method when
  formatting a number ("int", "float", "float" and subclasses) with
  the "n" type (ex: "'{:n}'.format(1234)").

* bpo-31853: Use super().method instead of socket.method in
  SSLSocket. They were there most likely for legacy reasons.

* bpo-31399: The ssl module now uses OpenSSL's
  X509_VERIFY_PARAM_set1_host() and X509_VERIFY_PARAM_set1_ip() API to
  verify hostname and IP addresses. Subject common name fallback can
  be disabled with SSLContext.hostname_checks_common_name.

* bpo-14976: Add a queue.SimpleQueue class, an unbounded FIFO queue
  with a reentrant C implementation of put().


文档
----

* bpo-32724: Add references to some commands in the documentation of
  Pdb. Patch by Stéphane Wirtel

* bpo-32649: Complete the C API documentation, profiling and tracing
  part with the newly added per-opcode events.

* bpo-17799: Explain real behaviour of sys.settrace and
  sys.setprofile and their C-API counterparts regarding which type of
  events are received in each function. Patch by Pablo Galindo
  Salgado.


测试
----

* bpo-32721: Fix test_hashlib to not fail if the _md5 module is not
  built.

* bpo-28414: Add test cases for IDNA 2003 and 2008 host names. IDNA
  2003 internationalized host names are working since bpo-31399 has
  landed. IDNA 2008 are still broken.

* bpo-32604: Add a new "_xxsubinterpreters" extension module that
  exposes the existing subinterpreter C-API and a new cross-
  interpreter data sharing mechanism. The module is primarily intended
  for more thorough testing of the existing subinterpreter support.
  Note that the _xxsubinterpreters module has been removed in
  3.7.0rc1.

* bpo-32602: Add test certs and test for ECDSA cert and EC/RSA dual
  mode.

* bpo-32549: On Travis CI, Python now Compiles and uses a local copy
  of OpenSSL 1.1.0g for testing.


构建
----

* bpo-32635: Fix segfault of the crypt module when libxcrypt is
  provided instead of libcrypt at the system.

* bpo-32598: Use autoconf to detect OpenSSL libs, headers and
  supported features. The ax_check_openssl M4 macro uses pkg-config to
  locate OpenSSL and falls back to manual search.

* bpo-32593: Drop support of FreeBSD 9 and older.

* bpo-29708: If the "SOURCE_DATE_EPOCH" environment variable is set,
  "py_compile" will always create hash-based ".pyc" files.


Windows
-------

* bpo-32588: Create standalone _distutils_findvs module and add
  missing _queue module to installer.

* bpo-29911: Ensure separate Modify and Uninstall buttons are
  displayed.

* bpo-32507: Use app-local UCRT install rather than the proper
  update for old versions of Windows.


macOS
-----

* bpo-32726: Provide an additional, more modern macOS installer
  variant that supports macOS 10.9+ systems in 64-bit mode only.
  Upgrade the supplied third-party libraries to OpenSSL 1.1.0g and to
  SQLite 3.22.0.  The 10.9+ installer now links with and supplies its
  own copy of Tcl/Tk 8.6.

* bpo-28440: No longer add /Library/Python/3.x/site-packages to
  sys.path for macOS framework builds to avoid future conflicts.


C API
-----

* bpo-32681: Fix uninitialized variable 'res' in the C
  implementation of os.dup2. Patch by Stéphane Wirtel

* bpo-10381: Add C API access to the "datetime.timezone" constructor
  and "datetime.timzone.UTC" singleton.


Python 3.7.0 alpha 4
====================

*Release date: 2018-01-08*


核心与内置
----------

* bpo-31975: The default warning filter list now starts with a
  "default::DeprecationWarning:__main__" entry, so deprecation
  warnings are once again shown by default in single-file scripts and
  at the interactive prompt.

* bpo-32226: "__class_getitem__" is now an automatic class method.

* bpo-32399: Add AIX uuid library support for RFC4122 using
  uuid_create() in libc.a

* bpo-32390: Fix the compilation failure on AIX after the f_fsid
  field has been added to the object returned by os.statvfs()
  (bpo-32143). Original patch by Michael Felt.

* bpo-32379: Make MRO computation faster when a class inherits from
  a single base.

* bpo-32259: The error message of a TypeError raised when unpack
  non- iterable is now more specific.

* bpo-27169: The "__debug__" constant is now optimized out at
  compile time. This fixes also bpo-22091.

* bpo-32329: The "-R" option now turns on hash randomization when
  the "PYTHONHASHSEED" environment variable is set to "0". Previously,
  the option was ignored. Moreover, "sys.flags.hash_randomization" is
  now properly set to 0 when hash randomization is turned off by
  "PYTHONHASHSEED=0".

* bpo-30416: The optimizer is now protected from spending much time
  doing complex calculations and consuming much memory for creating
  large constants in constant folding. Increased limits for constants
  that can be produced in constant folding.

* bpo-32282: Fix an unnecessary ifdef in the include of
  VersionHelpers.h in socketmodule on Windows.

* bpo-30579: Implement TracebackType.__new__ to allow Python-level
  creation of traceback objects, and make TracebackType.tb_next
  mutable.

* bpo-32260: Don't byte swap the input keys to the SipHash algorithm
  on big-endian platforms. This should ensure siphash gives consistent
  results across platforms.

* bpo-31506: Improve the error message logic for object.__new__ and
  object.__init__. Patch by Sanyam Khurana.

* bpo-20361: "-b" and "-bb" now inject "'default::BytesWarning'" and
  "error::BytesWarning" entries into "sys.warnoptions", ensuring that
  they take precedence over any other warning filters configured via
  the "-W" option or the "PYTHONWARNINGS" environment variable.

* bpo-32230: "-X dev" now injects a "'default'" entry into
  sys.warnoptions, ensuring that it behaves identically to actually
  passing "-Wdefault" at the command line.

* bpo-29240: Add a new UTF-8 mode: implementation of the **PEP
  540**.

* bpo-32226: **PEP 560**: Add support for "__mro_entries__" and
  "__class_getitem__". Implemented by Ivan Levkivskyi.

* bpo-32225: **PEP 562**: Add support for module "__getattr__" and
  "__dir__". Implemented by Ivan Levkivskyi.

* bpo-31901: The "atexit" module now has its callback stored per
  interpreter.

* bpo-31650: Implement **PEP 552** (Deterministic pycs). Python now
  supports invalidating bytecode cache files bashed on a source
  content hash rather than source last-modified time.

* bpo-29469: Move constant folding from bytecode layer to AST layer.
  Original patch by Eugene Toder.


库
--

* bpo-32506: Now that dict is defined as keeping insertion order,
  drop OrderedDict and just use plain dict.

* bpo-32279: Add params to dataclasses.make_dataclasses(): init,
  repr, eq, order, hash, and frozen.  Pass them through to
  dataclass().

* bpo-32278: Make type information optional on
  dataclasses.make_dataclass(). If omitted, the string 'typing.Any' is
  used.

* bpo-32499: Add dataclasses.is_dataclass(obj), which returns True
  if obj is a dataclass or an instance of one.

* bpo-32468: Improve frame repr() to mention filename, code name and
  current line number.

* bpo-23749: asyncio: Implement loop.start_tls()

* bpo-32441: Return the new file descriptor (i.e., the second
  argument) from "os.dup2". Previously, "None" was always returned.

* bpo-32422: "functools.lru_cache" uses less memory (3 words for
  each cached key) and takes about 1/3 time for cyclic GC.

* bpo-31721: Prevent Python crash from happening when
  Future._log_traceback is set to True manually.  Now it can only be
  set to False, or a ValueError is raised.

* bpo-32415: asyncio: Add Task.get_loop() and Future.get_loop()

* bpo-26133: Don't unsubscribe signals in asyncio UNIX event loop on
  interpreter shutdown.

* bpo-32363: Make asyncio.Task.set_exception() and set_result()
  raise NotImplementedError. Task._step() and Future.__await__() raise
  proper exceptions when they are in an invalid state, instead of
  raising an AssertionError.

* bpo-32357: Optimize asyncio.iscoroutine() and loop.create_task()
  for non-native coroutines (e.g. async/await compiled with Cython).
  'loop.create_task(python_coroutine)' used to be 20% faster than
  'loop.create_task(cython_coroutine)'.  Now, the latter is as fast.

* bpo-32356: asyncio.transport.resume_reading() and pause_reading()
  are now idempotent. New transport.is_reading() method is added.

* bpo-32355: Optimize asyncio.gather(); now up to 15% faster.

* bpo-32351: Use fastpath in asyncio.sleep if delay<0 (2x boost)

* bpo-32348: Optimize asyncio.Future schedule/add/remove callback.
  The optimization shows 3-6% performance improvements of async/await
  code.

* bpo-32331: Fix socket.settimeout() and socket.setblocking() to
  keep socket.type as is. Fix socket.socket() constructor to reset any
  bit flags applied to socket's type.  This change only affects OSes
  that have SOCK_NONBLOCK and/or SOCK_CLOEXEC.

* bpo-32248: Add "importlib.abc.ResourceReader" as an ABC for
  loaders to provide a unified API for reading resources contained
  within packages. Also add "importlib.resources" as the port of
  "importlib_resources".

* bpo-32311: Implement asyncio.create_task(coro) shortcut

* bpo-32327: Convert asyncio functions that were documented as
  coroutines to coroutines. Affected functions: loop.sock_sendall,
  loop.sock_recv, loop.sock_accept, loop.getaddrinfo,
  loop.getnameinfo.

* bpo-32323: "urllib.parse.urlsplit()" does not convert zone-id
  (scope) to lower case for scoped IPv6 addresses in hostnames now.

* bpo-32302: Fix bdist_wininst of distutils for CRT v142: it binary
  compatible with CRT v140.

* bpo-29711: Fix "stop_serving" in asyncio proactor loop kill all
  listening servers

* bpo-32308: "re.sub()" now replaces empty matches adjacent to a
  previous non-empty match.

* bpo-29970: Abort asyncio SSLProtocol connection if handshake not
  complete within 10s

* bpo-32314: Implement asyncio.run().

* bpo-17852: Revert incorrect fix based on misunderstanding of
  _Py_PyAtExit() semantics.

* bpo-32296: Implement asyncio._get_running_loop() and
  get_event_loop() in C. This makes them 4x faster.

* bpo-32250: Implement "asyncio.current_task()" and
  "asyncio.all_tasks()". Add helpers intended to be used by
  alternative task implementations: "asyncio._register_task",
  "asyncio._enter_task", "asyncio._leave_task" and
  "asyncio._unregister_task". Deprecate "asyncio.Task.current_task()"
  and "asyncio.Task.all_tasks()".

* bpo-32255: A single empty field is now always quoted when written
  into a CSV file. This allows to distinguish an empty row from a row
  consisting of a single empty field. Patch by Licht Takeuchi.

* bpo-32277: Raise "NotImplementedError" instead of "SystemError" on
  platforms where "chmod(..., follow_symlinks=False)" is not
  supported. Patch by Anthony Sottile.

* bpo-30050: New argument warn_on_full_buffer to
  signal.set_wakeup_fd lets you control whether Python prints a
  warning on stderr when the wakeup fd buffer overflows.

* bpo-29137: The "fpectl" library has been removed. It was never
  enabled by default, never worked correctly on x86-64, and it changed
  the Python ABI in ways that caused unexpected breakage of C
  extensions.

* bpo-32273: Move asyncio.test_utils to test.test_asyncio.

* bpo-32272: Remove asyncio.async() function.

* bpo-32269: Add asyncio.get_running_loop() function.

* bpo-32265: All class and static methods of builtin types now are
  correctly classified by inspect.classify_class_attrs() and grouped
  in pydoc ouput. Added types.ClassMethodDescriptorType for unbound
  class methods of builtin types.

* bpo-32253: Deprecate "yield from lock", "await lock", "with (yield
  from lock)" and "with await lock" for asyncio synchronization
  primitives.

* bpo-22589: Changed MIME type of .bmp from 'image/x-ms-bmp' to
  'image/bmp'

* bpo-32193: Convert asyncio to use *async/await* syntax. Old styled
  "yield from" is still supported too.

* bpo-32206: Add support to run modules with pdb

* bpo-32227: "functools.singledispatch" now supports registering
  implementations using type annotations.

* bpo-15873: Added new alternate constructors
  "datetime.datetime.fromisoformat()", "datetime.time.fromisoformat()"
  and "datetime.date.fromisoformat()" as the inverse operation of each
  classes's respective "isoformat" methods.

* bpo-32199: The getnode() ip getter now uses 'ip link' instead of
  'ip link list'.

* bpo-32143: os.statvfs() includes the f_fsid field from statvfs(2)

* bpo-26439: Fix ctypes.util.find_library() for AIX by implementing
  ctypes._aix.find_library() Patch by: Michael Felt

* bpo-31993: The pickler now uses less memory when serializing large
  bytes and str objects into a file.  Pickles created with protocol 4
  will require less memory for unpickling large bytes and str objects.

* bpo-27456: Ensure TCP_NODELAY is set on Linux. Tests by Victor
  Stinner.

* bpo-31778: ast.literal_eval() is now more strict. Addition and
  subtraction of arbitrary numbers no longer allowed.

* bpo-31802: Importing native path module ("posixpath", "ntpath")
  now works even if the "os" module still is not imported.

* bpo-30241: Add contextlib.AbstractAsyncContextManager. Patch by
  Jelle Zijlstra.

* bpo-31699: Fix deadlocks in
  "concurrent.futures.ProcessPoolExecutor" when task arguments or
  results cause pickling or unpickling errors. This should make sure
  that calls to the "ProcessPoolExecutor" API always eventually
  return.

* bpo-15216: "TextIOWrapper.reconfigure()" supports changing
  *encoding*, *errors*, and *newline*.


文档
----

* bpo-32418: Add get_loop() method to Server and AbstractServer
  classes.


测试
----

* bpo-32252: Fix faulthandler_suppress_crash_report() used to
  prevent core dump files when testing crashes. getrlimit() returns
  zero on success.

* bpo-32002: Adjust C locale coercion testing for the empty locale
  and POSIX locale cases to more readily adjust to platform dependent
  behaviour.


Windows
-------

* bpo-19764: Implement support for
  "subprocess.Popen(close_fds=True)" on Windows. Patch by Segev Finer.


工具/示例
---------

* bpo-24960: 2to3 and lib2to3 can now read pickled grammar files
  using pkgutil.get_data() rather than probing the filesystem. This
  lets 2to3 and lib2to3 work when run from a zipfile.


C API
-----

* bpo-32030: Py_Initialize() doesn't reset the memory allocators to
  default if the "PYTHONMALLOC" environment variable is not set.

* bpo-29084: Undocumented C API for OrderedDict has been excluded
  from the limited C API. It was added by mistake and actually never
  worked in the limited C API.

* bpo-32264: Moved the pygetopt.h header into internal/, since it
  has no public APIs.

* bpo-32241: "Py_SetProgramName()" and "Py_SetPythonHome()" now take
  the "const wchar *" arguments instead of "wchar *".


Python 3.7.0 alpha 3
====================

*Release date: 2017-12-05*


核心与内置
----------

* bpo-32176: co_flags.CO_NOFREE is now always set correctly by the
  code object constructor based on freevars and cellvars, rather than
  needing to be set correctly by the caller. This ensures it will be
  cleared automatically when additional cell references are injected
  into a modified code object and function.

* bpo-10544: Yield expressions are now deprecated in comprehensions
  and generator expressions. They are still permitted in the
  definition of the outermost iterable, as that is evaluated directly
  in the enclosing scope.

* bpo-32137: The repr of deeply nested dict now raises a
  RecursionError instead of crashing due to a stack overflow.

* bpo-32096: Revert memory allocator changes in the C API: move
  structures back from _PyRuntime to Objects/obmalloc.c. The memory
  allocators are once again initialized statically, and so
  PyMem_RawMalloc() and Py_DecodeLocale() can be called before
  _PyRuntime_Initialize().

* bpo-32043: Add a new "developer mode": new "-X dev" command line
  option to enable debug checks at runtime.

* bpo-32023: SyntaxError is now correctly raised when a generator
  expression without parenthesis is used instead of an inheritance
  list in a class definition. The duplication of the parentheses can
  be omitted only on calls.

* bpo-32012: SyntaxError is now correctly raised when a generator
  expression without parenthesis is passed as an argument, but
  followed by a trailing comma. A generator expression always needs to
  be directly inside a set of parentheses and cannot have a comma on
  either side.

* bpo-28180: A new internal "_Py_SetLocaleFromEnv(category)" helper
  function has been added in order to improve the consistency of
  behaviour across different "libc" implementations (e.g. Android
  doesn't support setting the locale from the environment by default).

* bpo-31949: Fixed several issues in printing tracebacks
  (PyTraceBack_Print()). Setting sys.tracebacklimit to 0 or less now
  suppresses printing tracebacks. Setting sys.tracebacklimit to None
  now causes using the default limit. Setting sys.tracebacklimit to an
  integer larger than LONG_MAX now means using the limit LONG_MAX
  rather than the default limit. Fixed integer overflows in the case
  of more than 2**31 traceback items on Windows. Fixed output errors
  handling.

* bpo-30696: Fix the interactive interpreter looping endlessly when
  no memory.

* bpo-20047: Bytearray methods partition() and rpartition() now
  accept only bytes-like objects as separator, as documented.  In
  particular they now raise TypeError rather of returning a bogus
  result when an integer is passed as a separator.

* bpo-21720: BytesWarning no longer emitted when the *fromlist*
  argument of "__import__()" or the "__all__" attribute of the module
  contain bytes instances.

* bpo-31845: Environment variables are once more read correctly at
  interpreter startup.

* bpo-28936: Ensure that lexically first syntax error involving a
  parameter and "global" or "nonlocal" is detected first at a given
  scope. Patch by Ivan Levkivskyi.

* bpo-31825: Fixed OverflowError in the 'unicode-escape' codec and
  in codecs.escape_decode() when decode an escaped non-ascii byte.

* bpo-31618: The per-frame tracing logic added in 3.7a1 has been
  altered so that "frame->f_lineno" is updated before either ""line""
  or ""opcode"" events are emitted. Previously, opcode events were
  emitted first, and therefore would occasionally see stale line
  numbers on the frame. The behavior of this feature has changed
  slightly as a result: when both "f_trace_lines" and
  "f_trace_opcodes" are enabled, line events now occur first.

* bpo-28603: Print the full context/cause chain of exceptions on
  interpreter exit, even if an exception in the chain is unhashable or
  compares equal to later ones. Patch by Zane Bitter.

* bpo-31786: Fix timeout rounding in the select module to round
  correctly negative timeouts between -1.0 and 0.0. The functions now
  block waiting for events as expected. Previously, the call was
  incorrectly non-blocking. Patch by Pablo Galindo.

* bpo-31781: Prevent crashes when calling methods of an
  uninitialized "zipimport.zipimporter" object. Patch by Oren Milman.

* bpo-30399: Standard repr() of BaseException with a single argument
  no longer contains redundant trailing comma.

* bpo-31626: Fixed a bug in debug memory allocator.  There was a
  write to freed memory after shrinking a memory block.

* bpo-30817: "PyErr_PrintEx()" clears now the ignored exception that
  may be raised by "_PySys_SetObjectId()", for example when no memory.


库
--

* bpo-28556: Two minor fixes for "typing" module: allow shallow
  copying instances of generic classes, improve interaction of
  "__init_subclass__" with generics. Original PRs by Ivan Levkivskyi.

* bpo-32214: PEP 557, Data Classes. Provides a decorator which adds
  boilerplate methods to classes which use type annotations so specify
  fields.

* bpo-27240: The header folding algorithm for the new email policies
  has been rewritten, which also fixes bpo-30788, bpo-31831, and
  bpo-32182.  In particular, RFC2231 folding is now done correctly.

* bpo-32186: io.FileIO.readall() and io.FileIO.read() now release
  the GIL when getting the file size. Fixed hang of all threads with
  inaccessible NFS server. Patch by Nir Soffer.

* bpo-321010: Add "sys.flags.dev_mode" flag

* bpo-32154: The "asyncio.windows_utils.socketpair()" function has
  been removed: use directly "socket.socketpair()" which is available
  on all platforms since Python 3.5 (before, it wasn't available on
  Windows). "asyncio.windows_utils.socketpair()" was just an alias to
  "socket.socketpair" on Python 3.5 and newer.

* bpo-32089: warnings: In development (-X dev) and debug mode
  (pydebug build), use the "default" action for ResourceWarning,
  rather than the "always" action, in the default warnings filters.

* bpo-32107: "uuid.getnode()" now preferentially returns universally
  administered MAC addresses if available, over locally administered
  MAC addresses.  This makes a better guarantee for global uniqueness
  of UUIDs returned from "uuid.uuid1()".  If only locally administered
  MAC addresses are available, the first such one found is returned.

* bpo-23033: Wildcard is now supported in hostname when it is one
  and only character in the left most segment of hostname in second
  argument of "ssl.match_hostname()".  Patch by Mandeep Singh.

* bpo-12239: Make "msilib.SummaryInformation.GetProperty()" return
  "None" when the value of property is "VT_EMPTY".  Initial patch by
  Mark Mc Mahon.

* bpo-28334: Use "os.path.expanduser()" to find the "~/.netrc" file
  in "netrc.netrc".  If it does not exist, "FileNotFoundError" is
  raised. Patch by Dimitri Merejkowsky.

* bpo-32121: Made "tracemalloc.Traceback" behave more like the
  traceback module, sorting the frames from oldest to most recent.
  "Traceback.format()" now accepts negative *limit*, truncating the
  result to the "abs(limit)" oldest frames. To get the old behaviour,
  one can use the new *most_recent_first* argument to
  "Traceback.format()". (Patch by Jesse Bakker.)

* bpo-31325: Fix wrong usage of "collections.namedtuple()" in the
  "RobotFileParser.parse()" method. Initial patch by Robin Wellner.

* bpo-12382: "msilib.OpenDatabase()" now raises a better exception
  message when it couldn't open or create an MSI file.  Initial patch
  by William Tisäter.

* bpo-19610: "setup()" now warns about invalid types for some
  fields. The "distutils.dist.Distribution" class now warns when
  "classifiers", "keywords" and "platforms" fields are not specified
  as a list or a string.

* bpo-32071: Added the "-k" command-line option to "python -m
  unittest" to run only tests that match the given pattern(s).

* bpo-10049: Added *nullcontext* no-op context manager to
  contextlib. This provides a simpler and faster alternative to
  ExitStack() when handling optional context managers.

* bpo-28684: The new test.support.skip_unless_bind_unix_socket()
  decorator is used here to skip asyncio tests that fail because the
  platform lacks a functional bind() function for unix domain sockets
  (as it is the case for non root users on the recent Android versions
  that run now SELinux in enforcing mode).

* bpo-32110: "codecs.StreamReader.read(n)" now returns not more than
  *n* characters/bytes for non-negative *n*. This makes it compatible
  with "read()" methods of other file-like objects.

* bpo-27535: The warnings module doesn't leak memory anymore in the
  hidden warnings registry for the "ignore" action of warnings
  filters. warn_explicit() function doesn't add the warning key to the
  registry anymore for the "ignore" action.

* bpo-32088: warnings:  When Python is build is debug mode
  ("Py_DEBUG"), "DeprecationWarning", "PendingDeprecationWarning" and
  "ImportWarning" warnings are now displayed by default.

* bpo-1647489: Fixed searching regular expression patterns that
  could match an empty string. Non-empty string can now be correctly
  found after matching an empty string.

* bpo-25054: Added support of splitting on a pattern that could
  match an empty string.

* bpo-32072: Fixed issues with binary plists: Fixed saving
  bytearrays. Identical objects will be saved only once. Equal
  references will be load as identical objects. Added support for
  saving and loading recursive data structures.

* bpo-32069: Drop legacy SSL transport from asyncio, ssl.MemoryBIO
  is always used anyway.

* bpo-32066: asyncio: Support pathlib.Path in
  create_unix_connection; sock arg should be optional

* bpo-32046: Updates 2to3 to convert from operator.isCallable(obj)
  to callable(obj). Patch by Dong-hee Na.

* bpo-32018: inspect.signature should follow **PEP 8**, if the
  parameter has an annotation and a default value. Patch by Dong-hee
  Na.

* bpo-32025: Add time.thread_time() and time.thread_time_ns()

* bpo-32037: Integers that fit in a signed 32-bit integer will be
  now pickled with protocol 0 using the INT opcode.  This will
  decrease the size of a pickle, speed up pickling and unpickling, and
  make these integers be unpickled as int instances in Python 2.

* bpo-32034: Make asyncio.IncompleteReadError and LimitOverrunError
  pickleable.

* bpo-32015: Fixed the looping of asyncio in the case of
  reconnection the socket during waiting async read/write from/to the
  socket.

* bpo-32011: Restored support of loading marshal files with the
  TYPE_INT64 code. These files can be produced in Python 2.7.

* bpo-28369: Enhance add_reader/writer check that socket is not used
  by some transport. Before, only cases when add_reader/writer were
  called with an int FD were supported.  Now the check is implemented
  correctly for all file-like objects.

* bpo-31976: Fix race condition when flushing a file is slow, which
  can cause a segfault if closing the file from another thread.

* bpo-31985: Formally deprecated aifc.openfp, sunau.openfp, and
  wave.openfp. Since change 7bc817d5ba917528e8bd07ec461c635291e7b06a
  in 1993, openfp in each of the three modules had been pointing to
  that module's open function as a matter of backwards compatibility,
  though it had been both untested and undocumented.

* bpo-21862: cProfile command line now accepts "-m module_name" as
  an alternative to script path. Patch by Sanyam Khurana.

* bpo-31970: Reduce performance overhead of asyncio debug mode.

* bpo-31843: *database* argument of sqlite3.connect() now accepts a
  *path-like object*, instead of just a string.

* bpo-31945: Add Configurable *blocksize* to "HTTPConnection" and
  "HTTPSConnection" for improved upload throughput.  Patch by Nir
  Soffer.

* bpo-31943: Add a "cancelled()" method to "asyncio.Handle".  Patch
  by Marat Sharafutdinov.

* bpo-9678: Fixed determining the MAC address in the uuid module:
  Using ifconfig on NetBSD and OpenBSD. Using arp on Linux, FreeBSD,
  NetBSD and OpenBSD. Based on patch by Takayuki Shimizukawa.

* bpo-30057: Fix potential missed signal in signal.signal().

* bpo-31933: Fix Blake2 params leaf_size and node_offset on big
  endian platforms. Patch by Jack O'Connor.

* bpo-21423: Add an initializer argument to
  {Process,Thread}PoolExecutor

* bpo-31927: Fixed compilation of the socket module on NetBSD 8.
  Fixed assertion failure or reading arbitrary data when parse a
  AF_BLUETOOTH address on NetBSD and DragonFly BSD.

* bpo-27666: Fixed stack corruption in curses.box() and
  curses.ungetmouse() when the size of types chtype or mmask_t is less
  than the size of C long. curses.box() now accepts characters as
  arguments.  Based on patch by Steve Fink.

* bpo-31917: Add 3 new clock identifiers: "time.CLOCK_BOOTTIME",
  "time.CLOCK_PROF" and "time.CLOCK_UPTIME".

* bpo-31897: plistlib now catches more errors when read binary
  plists and raises InvalidFileException instead of unexpected
  exceptions.

* bpo-25720: Fix the method for checking pad state of curses WINDOW.
  Patch by Masayuki Yamamoto.

* bpo-31893: Fixed the layout of the kqueue_event structure on
  OpenBSD and NetBSD. Fixed the comparison of the kqueue_event
  objects.

* bpo-31891: Fixed building the curses module on NetBSD.

* bpo-31884: added required constants to subprocess module for
  setting priority on windows

* bpo-28281: Remove year (1-9999) limits on the Calendar.weekday()
  function. Patch by Mark Gollahon.

* bpo-31702: crypt.mksalt() now allows to specify the number of
  rounds for SHA-256 and SHA-512 hashing.

* bpo-30639: "inspect.getfile()" no longer computes the repr of
  unknown objects to display in an error message, to protect against
  badly behaved custom reprs.

* bpo-30768: Fix the pthread+semaphore implementation of
  PyThread_acquire_lock_timed() when called with timeout > 0 and
  intr_flag=0: recompute the timeout if sem_timedwait() is interrupted
  by a signal (EINTR). See also the **PEP 475**.

* bpo-31854: Add "mmap.ACCESS_DEFAULT" constant.

* bpo-31834: Use optimized code for BLAKE2 only with SSSE3+. The
  pure SSE2 implementation is slower than the pure C reference
  implementation.

* bpo-28292: Calendar.itermonthdates() will now consistently raise
  an exception when a date falls outside of the 0001-01-01 through
  9999-12-31 range.  To support applications that cannot tolerate such
  exceptions, the new methods itermonthdays3() and itermonthdays4()
  are added.  The new methods return tuples and are not restricted by
  the range supported by datetime.date.

* bpo-28564: The shutil.rmtree() function has been sped up to 20--
  40%. This was done using the os.scandir() function.

* bpo-28416: Instances of pickle.Pickler subclass with the
  persistent_id() method and pickle.Unpickler subclass with the
  persistent_load() method no longer create reference cycles.

* bpo-31653: Don't release the GIL if we can acquire a
  multiprocessing semaphore immediately.

* bpo-28326: Fix multiprocessing.Process when stdout and/or stderr
  is closed or None.

* bpo-20825: Add "subnet_of" and "superset_of" containment tests to
  "ipaddress.IPv6Network" and "ipaddress.IPv4Network". Patch by Michel
  Albert and Cheryl Sabella.

* bpo-31827: Remove the os.stat_float_times() function. It was
  introduced in Python 2.3 for backward compatibility with Python 2.2,
  and was deprecated since Python 3.1.

* bpo-31756: Add a "subprocess.Popen(text=False)" keyword argument
  to "subprocess" functions to be more explicit about when the library
  should attempt to decode outputs into text. Patch by Andrew Clegg.

* bpo-31819: Add AbstractEventLoop.sock_recv_into().

* bpo-31457: If nested log adapters are used, the inner "process()"
  methods are no longer omitted.

* bpo-31457: The "manager" property on LoggerAdapter objects is now
  properly settable.

* bpo-31806: Fix timeout rounding in time.sleep(),
  threading.Lock.acquire() and socket.socket.settimeout() to round
  correctly negative timeouts between -1.0 and 0.0. The functions now
  block waiting for events as expected. Previously, the call was
  incorrectly non-blocking. Patch by Pablo Galindo.

* bpo-31803: time.clock() and time.get_clock_info('clock') now emit
  a DeprecationWarning warning.

* bpo-31800: Extended support for parsing UTC offsets. strptime '%z'
  can now parse the output generated by datetime.isoformat, including
  seconds and microseconds.

* bpo-28603: traceback: Fix a TypeError that occurred during
  printing of exception tracebacks when either the current exception
  or an exception in its context/cause chain is unhashable. Patch by
  Zane Bitter.

* bpo-30541: Add new function to seal a mock and prevent the
  automatically creation of child mocks. Patch by Mario Corchero.

* bpo-31784: Implement the **PEP 564**, add new 6 new functions with
  nanosecond resolution to the "time" module: "clock_gettime_ns()",
  "clock_settime_ns()", "monotonic_ns()", "perf_counter_ns()",
  "process_time_ns()", "time_ns()".

* bpo-30143: 2to3 now generates a code that uses abstract collection
  classes from collections.abc rather than collections.

* bpo-31770: Prevent a crash when calling the "__init__()" method of
  a "sqlite3.Cursor" object more than once. Patch by Oren Milman.

* bpo-31764: Prevent a crash in "sqlite3.Cursor.close()" in case the
  "Cursor" object is uninitialized. Patch by Oren Milman.

* bpo-31752: Fix possible crash in timedelta constructor called with
  custom integers.

* bpo-31620: an empty asyncio.Queue now doesn't leak memory when
  queue.get pollers timeout

* bpo-31690: Allow the flags re.ASCII, re.LOCALE, and re.UNICODE to
  be used as group flags for regular expressions.

* bpo-30349: FutureWarning is now emitted if a regular expression
  contains character set constructs that will change semantically in
  the future (nested sets and set operations).

* bpo-31664: Added support for the Blowfish hashing in the crypt
  module.

* bpo-31632: Fix method set_protocol() of class
  _SSLProtocolTransport in asyncio module. This method was previously
  modifying a wrong reference to the protocol.

* bpo-15037: Added a workaround for getkey() in curses for ncurses
  5.7 and earlier.

* bpo-31307: Allow use of bytes objects for arguments to
  "configparser.ConfigParser.read()". Patch by Vincent Michel.

* bpo-31334: Fix "poll.poll([timeout])" in the "select" module for
  arbitrary negative timeouts on all OSes where it can only be a non-
  negative integer or -1. Patch by Riccardo Coccioli.

* bpo-31310: multiprocessing's semaphore tracker should be launched
  again if crashed.

* bpo-31308: Make multiprocessing's forkserver process immune to
  Ctrl-C and other user interruptions. If it crashes, restart it when
  necessary.

* bpo-31245: Added support for AF_UNIX socket in asyncio
  "create_datagram_endpoint".

* bpo-30553: Add HTTP/2 status code 421 (Misdirected Request) to
  "http.HTTPStatus". Patch by Vitor Pereira.


文档
----

* bpo-32105: Added asyncio.BaseEventLoop.connect_accepted_socket
  versionadded marker.


测试
----

* bpo-31380: Skip test_httpservers test_undecodable_file on macOS:
  fails on APFS.

* bpo-31705: Skip test_socket.test_sha256() on Linux kernel older
  than 4.5. The test fails with ENOKEY on kernel 3.10 (on ppc64le). A
  fix was merged into the kernel 4.5.

* bpo-32138: Skip on Android test_faulthandler tests that raise
  SIGSEGV and remove the test.support.requires_android_level
  decorator.

* bpo-32136: The runtime embedding tests have been split out from
  "Lib/test/test_capi.py" into a new "Lib/test/test_embed.py" file.

* bpo-28668: test.support.requires_multiprocessing_queue is removed.
  Skip tests with
  test.support.import_module('multiprocessing.synchronize') instead
  when the semaphore implementation is broken or missing.

* bpo-32126: Skip test_get_event_loop_new_process in
  test.test_asyncio.test_events when sem_open() is not functional.

* bpo-31174: Fix test_tools.test_unparse: DirectoryTestCase now
  stores the names sample to always test the same files. It prevents
  false alarms when hunting reference leaks.


构建
----

* bpo-28538: Revert the previous changes, the if_nameindex structure
  is defined by Unified Headers.

* bpo-28762: Revert the last commit, the F_LOCK macro is defined by
  Android Unified Headers.

* bpo-29040: Support building Android with Unified Headers. The
  first NDK release to support Unified Headers is android-ndk-r14.

* bpo-32059: "detect_modules()" in "setup.py" now also searches the
  sysroot paths when cross-compiling.

* bpo-31957: Fixes Windows SDK version detection when building for
  Windows.

* bpo-31609: Fixes quotes in PCbuild/clean.bat

* bpo-31934: Abort the build when building out of a not clean source
  tree.

* bpo-31926: Fixed Argument Clinic sometimes causing compilation
  errors when there was more than one function and/or method in a .c
  file with the same name.

* bpo-28791: Update Windows builds to use SQLite 3.21.0.

* bpo-28791: Update OS X installer to use SQLite 3.21.0.

* bpo-28643: Record profile-opt build progress with stamp files.

* bpo-31866: Finish removing support for AtheOS.


Windows
-------

* bpo-1102: Return "None" when "View.Fetch()" returns
  "ERROR_NO_MORE_ITEMS" instead of raising "MSIError". Initial patch
  by Anthony Tuininga.

* bpo-31944: Fixes Modify button in Apps and Features dialog.

* bpo-20486: Implement the "Database.Close()" method to help closing
  MSI database objects.

* bpo-31857: Make the behavior of USE_STACKCHECK deterministic in a
  multi-threaded environment.


macOS
-----

* bpo-31392: Update macOS installer to use OpenSSL 1.0.2m


IDLE
----

* bpo-32207: Improve tk event exception tracebacks in IDLE. When tk
  event handling is driven by IDLE's run loop, a confusing and
  distracting queue.EMPTY traceback context is no longer added to tk
  event exception tracebacks.  The traceback is now the same as when
  event handling is driven by user code.  Patch based on a suggestion
  by Serhiy Storchaka.

* bpo-32164: Delete unused file idlelib/tabbedpages.py. Use of
  TabbedPageSet in configdialog was replaced by ttk.Notebook.

* bpo-32100: IDLE: Fix old and new bugs in pathbrowser; improve
  tests. Patch mostly by Cheryl Sabella.

* bpo-31858: IDLE -- Restrict shell prompt manipulation to the
  shell. Editor and output windows only see an empty last prompt line.
  This simplifies the code and fixes a minor bug when newline is
  inserted. Sys.ps1, if present, is read on Shell start-up, but is not
  set or changed.

* bpo-31860: The font sample in the IDLE configuration dialog is now
  editable. Changes persist while IDLE remains open

* bpo-31836: Test_code_module now passes if run after test_idle,
  which sets ps1. The code module uses sys.ps1 if present or sets it
  to '>>> ' if not. Test_code_module now properly tests both
  behaviors.  Ditto for ps2.

* bpo-28603: Fix a TypeError that caused a shell restart when
  printing a traceback that includes an exception that is unhashable.
  Patch by Zane Bitter.

* bpo-13802: Use non-Latin characters in the IDLE's Font settings
  sample. Even if one selects a font that defines a limited subset of
  the unicode Basic Multilingual Plane, tcl/tk will use other fonts
  that define a character. The expanded example give users of non-
  Latin characters a better idea of what they might see in IDLE's
  shell and editors. To make room for the expanded sample, frames on
  the Font tab are re-arranged.  The Font/Tabs help explains a bit
  about the additions.


工具/示例
---------

* bpo-32159: Remove CVS and Subversion tools: remove svneol.py and
  treesync.py scripts. CPython migrated from CVS to Subversion, to
  Mercurial, and then to Git. CVS and Subversion are no longer used to
  develop CPython.

* bpo-30722: Make redemo work with Python 3.6 and newer versions.
  Also, remove the "LOCALE" option since it doesn't work with string
  patterns in Python 3. Patch by Christoph Sarnowski.


C API
-----

* bpo-20891: Fix PyGILState_Ensure(). When PyGILState_Ensure() is
  called in a non-Python thread before PyEval_InitThreads(), only call
  PyEval_InitThreads() after calling PyThreadState_New() to fix a
  crash.

* bpo-32125: The "Py_UseClassExceptionsFlag" flag has been removed.
  It was deprecated and wasn't used anymore since Python 2.0.

* bpo-25612: Move the current exception state from the frame object
  to the co-routine. This simplifies the interpreter and fixes a
  couple of obscure bugs caused by having swap exception state when
  entering or exiting a generator.

* bpo-23699: Add Py_RETURN_RICHCOMPARE macro to reduce boilerplate
  code in rich comparison functions.

* bpo-30697: The "PyExc_RecursionErrorInst" singleton is removed and
  "PyErr_NormalizeException()" does not use it anymore. This singleton
  is persistent and its members being never cleared may cause a
  segfault during finalization of the interpreter. See also bpo-22898.


Python 3.7.0 alpha 2
====================

*Release date: 2017-10-16*


核心与内置
----------

* bpo-31558: "gc.freeze()" is a new API that allows for moving all
  objects currently tracked by the garbage collector to a permanent
  generation, effectively removing them from future collection events.
  This can be used to protect those objects from having their
  PyGC_Head mutated. In effect, this enables great copy-on-write
  stability at fork().

* bpo-31642: Restored blocking "from package import module" by
  setting sys.modules["package.module"] to None.

* bpo-31708: Allow use of asynchronous generator expressions in
  synchronous functions.

* bpo-31709: Drop support of asynchronous __aiter__.

* bpo-30404: The -u option now makes the stdout and stderr streams
  unbuffered rather than line-buffered.

* bpo-31619: Fixed a ValueError when convert a string with large
  number of underscores to integer with binary base.

* bpo-31602: Fix an assertion failure in "zipimporter.get_source()"
  in case of a bad "zlib.decompress()". Patch by Oren Milman.

* bpo-31592: Fixed an assertion failure in Python parser in case of
  a bad "unicodedata.normalize()". Patch by Oren Milman.

* bpo-31588: Raise a "TypeError" with a helpful error message when
  class creation fails due to a metaclass with a bad "__prepare__()"
  method. Patch by Oren Milman.

* bpo-31574: Importlib was instrumented with two dtrace probes to
  profile import timing.

* bpo-31566: Fix an assertion failure in "_warnings.warn()" in case
  of a bad "__name__" global. Patch by Oren Milman.

* bpo-31506: Improved the error message logic for object.__new__ and
  object.__init__.

* bpo-31505: Fix an assertion failure in "json", in case
  "_json.make_encoder()" received a bad "encoder()" argument. Patch by
  Oren Milman.

* bpo-31492: Fix assertion failures in case of failing to import
  from a module with a bad "__name__" attribute, and in case of
  failing to access an attribute of such a module. Patch by Oren
  Milman.

* bpo-31478: Fix an assertion failure in "_random.Random.seed()" in
  case the argument has a bad "__abs__()" method. Patch by Oren
  Milman.

* bpo-31336: Speed up class creation by 10-20% by reducing the
  overhead in the necessary special method lookups.  Patch by Stefan
  Behnel.

* bpo-31415: Add "-X importtime" option to show how long each import
  takes. It can be used to optimize application's startup time.
  Support the "PYTHONPROFILEIMPORTTIME" as an equivalent way to enable
  this.

* bpo-31410: Optimized calling wrapper and classmethod descriptors.

* bpo-31353: **PEP 553** - Add a new built-in called "breakpoint()"
  which calls "sys.breakpointhook()".  By default this imports "pdb"
  and calls "pdb.set_trace()", but users may override
  "sys.breakpointhook()" to call whatever debugger they want.  The
  original value of the hook is saved in "sys.__breakpointhook__".

* bpo-17852: Maintain a list of open buffered files, flush them
  before exiting the interpreter.  Based on a patch from Armin Rigo.

* bpo-31315: Fix an assertion failure in imp.create_dynamic(), when
  spec.name is not a string. Patch by Oren Milman.

* bpo-31311: Fix a crash in the "__setstate__()" method of
  "ctypes._CData", in case of a bad "__dict__". Patch by Oren Milman.

* bpo-31293: Fix crashes in true division and multiplication of a
  timedelta object by a float with a bad as_integer_ratio() method.
  Patch by Oren Milman.

* bpo-31285: Fix an assertion failure in "warnings.warn_explicit",
  when the return value of the received loader's get_source() has a
  bad splitlines() method. Patch by Oren Milman.

* bpo-30406: Make "async" and "await" proper keywords, as specified
  in **PEP 492**.


库
--

* bpo-30058: Fixed buffer overflow in select.kqueue.control().

* bpo-31672: "idpattern" in "string.Template" matched some non-ASCII
  characters. Now it uses "-i" regular expression local flag to avoid
  non-ASCII characters.

* bpo-31701: On Windows, faulthandler.enable() now ignores MSC and
  COM exceptions.

* bpo-31728: Prevent crashes in "_elementtree" due to unsafe cleanup
  of "Element.text" and "Element.tail". Patch by Oren Milman.

* bpo-31671: Now "re.compile()" converts passed RegexFlag to normal
  int object before compiling. bm_regex_compile benchmark shows 14%
  performance improvements.

* bpo-30397: The types of compiled regular objects and match objects
  are now exposed as "re.Pattern" and "re.Match".  This adds
  information in pydoc output for the re module.

* bpo-31675: Fixed memory leaks in Tkinter's methods splitlist() and
  split() when pass a string larger than 2 GiB.

* bpo-31673: Fixed typo in the name of Tkinter's method
  adderrorinfo().

* bpo-31648: Improvements to path predicates in ElementTree: Allow
  whitespace around predicate parts, i.e. "[a = 'text']" instead of
  requiring the less readable "[a='text']". Add support for text
  comparison of the current node, like "[.='text']". Patch by Stefan
  Behnel.

* bpo-30806: Fix the string representation of a netrc object.

* bpo-31638: Add optional argument "compressed" to
  "zipapp.create_archive", and add option "--compress" to the command
  line interface of "zipapp".

* bpo-25351: Avoid venv activate failures with undefined variables

* bpo-20519: Avoid ctypes use (if possible) and improve import time
  for uuid.

* bpo-28293: The regular expression cache is no longer completely
  dumped when it is full.

* bpo-31596: Added pthread_getcpuclockid() to the time module

* bpo-27494: Make 2to3 accept a trailing comma in generator
  expressions. For example, "set(x for x in [],)" is now allowed.

* bpo-30347: Stop crashes when concurrently iterate over
  itertools.groupby() iterators.

* bpo-30346: An iterator produced by itertools.groupby() iterator
  now becomes exhausted after advancing the groupby iterator.

* bpo-31556: Cancel asyncio.wait_for future faster if timeout <= 0

* bpo-31540: Allow passing a context object in
  "concurrent.futures.ProcessPoolExecutor" constructor. Also, free job
  resources in "concurrent.futures.ProcessPoolExecutor" earlier to
  improve memory usage when a worker waits for new jobs.

* bpo-31516: "threading.current_thread()" should not return a dummy
  thread at shutdown.

* bpo-31525: In the sqlite module, require the sqlite3_prepare_v2
  API. Thus, the sqlite module now requires sqlite version at least
  3.3.9.

* bpo-26510: argparse subparsers are now required by default.  This
  matches behaviour in Python 2. For optional subparsers, use the new
  parameter "add_subparsers(required=False)". Patch by Anthony
  Sottile. (As of 3.7.0rc1, the default was changed to not required as
  had been the case since Python 3.3.)

* bpo-27541: Reprs of subclasses of some collection and iterator
  classes ("bytearray", "array.array", "collections.deque",
  "collections.defaultdict", "itertools.count", "itertools.repeat")
  now contain actual type name insteads of hardcoded name of the base
  class.

* bpo-31351: python -m ensurepip now exits with non-zero exit code
  if pip bootstrapping has failed.

* bpo-31389: "pdb.set_trace()" now takes an optional keyword-only
  argument "header". If given, this is printed to the console just
  before debugging begins.


文档
----

* bpo-31537: Fix incorrect usage of "get_history_length" in readline
  documentation example code. Patch by Brad Smith.

* bpo-30085: The operator functions without double underscores are
  preferred for clarity. The one with underscores are only kept for
  back-compatibility.


构建
----

* bpo-31696: Improve compiler version information in "sys.version"
  when Python is built with Clang.

* bpo-31625: Stop using ranlib on static libraries. Instead, we
  assume ar supports the 's' flag.

* bpo-31624: Remove support for BSD/OS.

* bpo-22140: Prevent double substitution of prefix in python-
  config.sh.

* bpo-31569: Correct PCBuild/ case to PCbuild/ in build scripts and
  documentation.

* bpo-31536: Avoid wholesale rebuild after "make regen-all" if
  nothing changed.


IDLE
----

* bpo-31460: Simplify the API of IDLE's Module Browser. Passing a
  widget instead of an flist with a root widget opens the option of
  creating a browser frame that is only part of a window.  Passing a
  full file name instead of pieces assumed to come from a .py file
  opens the possibility of browsing python files that do not end in
  .py.

* bpo-31649: IDLE - Make _htest, _utest parameters keyword only.

* bpo-31559: Remove test order dependence in idle_test.test_browser.

* bpo-31459: Rename IDLE's module browser from Class Browser to
  Module Browser. The original module-level class and method browser
  became a module browser, with the addition of module-level
  functions, years ago. Nested classes and functions were added
  yesterday.  For back- compatibility, the virtual event <<open-class-
  browser>>, which appears on the Keys tab of the Settings dialog, is
  not changed. Patch by Cheryl Sabella.

* bpo-31500: Default fonts now are scaled on HiDPI displays.

* bpo-1612262: IDLE module browser now shows nested classes and
  functions. Original patches for code and tests by Guilherme Polo and
  Cheryl Sabella, respectively.


C API
-----

* bpo-28280: Make "PyMapping_Keys()", "PyMapping_Values()" and
  "PyMapping_Items()" always return a "list" (rather than a "list" or
  a "tuple"). Patch by Oren Milman.

* bpo-31532: Fix memory corruption due to allocator mix in getpath.c
  between Py_GetPath() and Py_SetPath()

* bpo-25658: Implement **PEP 539** for Thread Specific Storage (TSS)
  API: it is a new Thread Local Storage (TLS) API to CPython which
  would supersede use of the existing TLS API within the CPython
  interpreter, while deprecating the existing API. PEP written by Erik
  M. Bray, patch by Masayuki Yamamoto.


Python 3.7.0 alpha 1
====================

*Release date: 2017-09-19*


安全
----

* bpo-29781: SSLObject.version() now correctly returns None when
  handshake over BIO has not been performed yet.

* bpo-29505: Add fuzz tests for float(str), int(str), unicode(str);
  for oss-fuzz.

* bpo-30947: Upgrade libexpat embedded copy from version 2.2.1 to
  2.2.3 to get security fixes.

* bpo-30730: Prevent environment variables injection in subprocess
  on Windows.  Prevent passing other environment variables and command
  arguments.

* bpo-30694: Upgrade expat copy from 2.2.0 to 2.2.1 to get fixes of
  multiple security vulnerabilities including: CVE-2017-9233 (External
  entity infinite loop DoS), CVE-2016-9063 (Integer overflow, re-fix),
  CVE-2016-0718 (Fix regression bugs from 2.2.0's fix to
  CVE-2016-0718) and CVE-2012-0876 (Counter hash flooding with
  SipHash). Note: the CVE-2016-5300 (Use os-specific entropy sources
  like getrandom) doesn't impact Python, since Python already gets
  entropy from the OS to set the expat secret using
  "XML_SetHashSalt()".

* bpo-30500: Fix urllib.parse.splithost() to correctly parse
  fragments. For example, "splithost('//127.0.0.1#@evil.com/')" now
  correctly returns the "127.0.0.1" host, instead of treating
  "@evil.com" as the host in an authentication ("login@host").

* bpo-29591: Update expat copy from 2.1.1 to 2.2.0 to get fixes of
  CVE-2016-0718 and CVE-2016-4472. See
  https://sourceforge.net/p/expat/bugs/537/ for more information.


核心与内置
----------

* bpo-31490: Fix an assertion failure in "ctypes" class definition,
  in case the class has an attribute whose name is specified in
  "_anonymous_" but not in "_fields_". Patch by Oren Milman.

* bpo-31471: Fix an assertion failure in "subprocess.Popen()" on
  Windows, in case the env argument has a bad keys() method. Patch by
  Oren Milman.

* bpo-31418: Fix an assertion failure in "PyErr_WriteUnraisable()"
  in case of an exception with a bad "__module__" attribute. Patch by
  Oren Milman.

* bpo-31416: Fix assertion failures in case of a bad
  warnings.filters or warnings.defaultaction. Patch by Oren Milman.

* bpo-28411: Change direct usage of PyInterpreterState.modules to
  PyImport_GetModuleDict(). Also introduce more uniformity in other
  code that deals with sys.modules. This helps reduce complications
  when working on sys.modules.

* bpo-28411: Switch to the abstract API when dealing with
  "PyInterpreterState.modules". This allows later support for all dict
  subclasses and other Mapping implementations.  Also add a
  "PyImport_GetModule()" function to reduce a bunch of duplicated
  code.

* bpo-31411: Raise a TypeError instead of SystemError in case
  warnings.onceregistry is not a dictionary. Patch by Oren Milman.

* bpo-31344: For finer control of tracing behaviour when testing the
  interpreter, two new frame attributes have been added to control the
  emission of particular trace events: "f_trace_lines" ("True" by
  default) to turn off per-line trace events; and "f_trace_opcodes"
  ("False" by default) to turn on per-opcode trace events.

* bpo-31373: Fix several possible instances of undefined behavior
  due to floating-point demotions.

* bpo-30465: Location information ("lineno" and "col_offset") in
  f-strings is now (mostly) correct.  This fixes tools like flake8
  from showing warnings on the wrong line (typically the first line of
  the file).

* bpo-30860: Consolidate CPython's global runtime state under a
  single struct.  This improves discoverability of the runtime state.

* bpo-31347: Fix possible undefined behavior in
  _PyObject_FastCall_Prepend.

* bpo-31343: Include sys/sysmacros.h for major(), minor(), and
  makedev(). GNU C libray plans to remove the functions from
  sys/types.h.

* bpo-31291: Fix an assertion failure in
  "zipimport.zipimporter.get_data" on Windows, when the return value
  of "pathname.replace('/','\\')" isn't a string. Patch by Oren
  Milman.

* bpo-31271: Fix an assertion failure in the write() method of
  "io.TextIOWrapper", when the encoder doesn't return a bytes object.
  Patch by Oren Milman.

* bpo-31243: Fix a crash in some methods of "io.TextIOWrapper", when
  the decoder's state is invalid. Patch by Oren Milman.

* bpo-30721: "print" now shows correct usage hint for using Python 2
  redirection syntax.  Patch by Sanyam Khurana.

* bpo-31070: Fix a race condition in importlib _get_module_lock().

* bpo-30747: Add a non-dummy implementation of _Py_atomic_store and
  _Py_atomic_load on MSVC.

* bpo-31095: Fix potential crash during GC caused by "tp_dealloc"
  which doesn't call "PyObject_GC_UnTrack()".

* bpo-31071: Avoid masking original TypeError in call with *
  unpacking when other arguments are passed.

* bpo-30978: str.format_map() now passes key lookup exceptions
  through. Previously any exception was replaced with a KeyError
  exception.

* bpo-30808: Use _Py_atomic API for concurrency-sensitive signal
  state.

* bpo-30876: Relative import from unloaded package now reimports the
  package instead of failing with SystemError.  Relative import from
  non-package now fails with ImportError rather than SystemError.

* bpo-30703: Improve signal delivery. Avoid using Py_AddPendingCall
  from signal handler, to avoid calling signal-unsafe functions. The
  tests I'm adding here fail without the rest of the patch, on Linux
  and OS X. This means our signal delivery logic had defects (some
  signals could be lost).

* bpo-30765: Avoid blocking in pthread_mutex_lock() when
  PyThread_acquire_lock() is asked not to block.

* bpo-31161: Make sure the 'Missing parentheses' syntax error
  message is only applied to SyntaxError, not to subclasses. Patch by
  Martijn Pieters.

* bpo-30814: Fixed a race condition when import a submodule from a
  package.

* bpo-30736: The internal unicodedata database has been upgraded to
  Unicode 10.0.

* bpo-30604: Move co_extra_freefuncs from per-thread to per-
  interpreter to avoid crashes.

* bpo-30597: "print" now shows expected input in custom error
  message when used as a Python 2 statement. Patch by Sanyam Khurana.

* bpo-30682: Removed a too-strict assertion that failed for certain
  f-strings, such as eval("f'\n'") and eval("f'\r'").

* bpo-30501: The compiler now produces more optimal code for complex
  condition expressions in the "if", "while" and "assert" statement,
  the "if" expression, and generator expressions and comprehensions.

* bpo-28180: Implement **PEP 538** (legacy C locale coercion). This
  means that when a suitable coercion target locale is available, both
  the core interpreter and locale-aware C extensions will assume the
  use of UTF-8 as the default text encoding, rather than ASCII.

* bpo-30486: Allows setting cell values for __closure__. Patch by
  Lisa Roach.

* bpo-30537: itertools.islice now accepts integer-like objects
  (having an __index__ method) as start, stop, and slice arguments

* bpo-25324: Tokens needed for parsing in Python moved to C.
  "COMMENT", "NL" and "ENCODING". This way the tokens and tok_names in
  the token module don't get changed when you import the tokenize
  module.

* bpo-29104: Fixed parsing backslashes in f-strings.

* bpo-27945: Fixed various segfaults with dict when input
  collections are mutated during searching, inserting or comparing.
  Based on patches by Duane Griffin and Tim Mitchell.

* bpo-25794: Fixed type.__setattr__() and type.__delattr__() for
  non- interned attribute names.  Based on patch by Eryk Sun.

* bpo-30039: If a KeyboardInterrupt happens when the interpreter is
  in the middle of resuming a chain of nested 'yield from' or 'await'
  calls, it's now correctly delivered to the innermost frame.

* bpo-28974: "object.__format__(x, '')" is now equivalent to
  "str(x)" rather than "format(str(self), '')".

* bpo-30024: Circular imports involving absolute imports with
  binding a submodule to a name are now supported.

* bpo-12414: sys.getsizeof() on a code object now returns the sizes
  which includes the code struct and sizes of objects which it
  references. Patch by Dong-hee Na.

* bpo-29839: len() now raises ValueError rather than OverflowError
  if __len__() returned a large negative integer.

* bpo-11913: README.rst is now included in the list of distutils
  standard READMEs and therefore included in source distributions.

* bpo-29914: Fixed default implementations of __reduce__ and
  __reduce_ex__(). object.__reduce__() no longer takes arguments,
  object.__reduce_ex__() now requires one argument.

* bpo-29949: Fix memory usage regression of set and frozenset
  object.

* bpo-29935: Fixed error messages in the index() method of tuple,
  list and deque when pass indices of wrong type.

* bpo-29816: Shift operation now has less opportunity to raise
  OverflowError. ValueError always is raised rather than OverflowError
  for negative counts. Shifting zero with non-negative count always
  returns zero.

* bpo-24821: Fixed the slowing down to 25 times in the searching of
  some unlucky Unicode characters.

* bpo-29102: Add a unique ID to PyInterpreterState.  This makes it
  easier to identify each subinterpreter.

* bpo-29894: The deprecation warning is emitted if __complex__
  returns an instance of a strict subclass of complex.  In a future
  versions of Python this can be an error.

* bpo-29859: Show correct error messages when any of the pthread_*
  calls in thread_pthread.h fails.

* bpo-29849: Fix a memory leak when an ImportError is raised during
  from import.

* bpo-28856: Fix an oversight that %b format for bytes should
  support objects follow the buffer protocol.

* bpo-29723: The "sys.path[0]" initialization change for bpo-29139
  caused a regression by revealing an inconsistency in how sys.path is
  initialized when executing "__main__" from a zipfile, directory, or
  other import location. The interpreter now consistently avoids ever
  adding the import location's parent directory to "sys.path", and
  ensures no other "sys.path" entries are inadvertently modified when
  inserting the import location named on the command line.

* bpo-29568: Escaped percent "%%" in the format string for classic
  string formatting no longer allows any characters between two
  percents.

* bpo-29714: Fix a regression that bytes format may fail when
  containing zero bytes inside.

* bpo-29695: bool(), float(), list() and tuple() no longer take
  keyword arguments. The first argument of int() can now be passes
  only as positional argument.

* bpo-28893: Set correct __cause__ for errors about invalid
  awaitables returned from __aiter__ and __anext__.

* bpo-28876: "bool(range)" works even if "len(range)" raises
  "OverflowError".

* bpo-29683: Fixes to memory allocation in _PyCode_SetExtra.  Patch
  by Brian Coleman.

* bpo-29684: Fix minor regression of PyEval_CallObjectWithKeywords.
  It should raise TypeError when kwargs is not a dict.  But it might
  cause segv when args=NULL and kwargs is not a dict.

* bpo-28598: Support __rmod__ for subclasses of str being called
  before str.__mod__. Patch by Martijn Pieters.

* bpo-29607: Fix stack_effect computation for CALL_FUNCTION_EX.
  Patch by Matthieu Dartiailh.

* bpo-29602: Fix incorrect handling of signed zeros in complex
  constructor for complex subclasses and for inputs having a
  __complex__ method. Patch by Serhiy Storchaka.

* bpo-29347: Fixed possibly dereferencing undefined pointers when
  creating weakref objects.

* bpo-29463: Add "docstring" field to Module, ClassDef, FunctionDef,
  and AsyncFunctionDef ast nodes.  docstring is not first stmt in
  their body anymore.  It affects "co_firstlineno" and "co_lnotab" of
  code object for module and class. (Reverted in bpo-32911.)

* bpo-29438: Fixed use-after-free problem in key sharing dict.

* bpo-29546: Set the 'path' and 'name' attribute on ImportError for
  "from ... import ...".

* bpo-29546: Improve from-import error message with location

* bpo-29478: If max_line_length=None is specified while using the
  Compat32 policy, it is no longer ignored.  Patch by Mircea Cosbuc.

* bpo-29319: Prevent RunMainFromImporter overwriting sys.path[0].

* bpo-29337: Fixed possible BytesWarning when compare the code
  objects. Warnings could be emitted at compile time.

* bpo-29327: Fixed a crash when pass the iterable keyword argument
  to sorted().

* bpo-29034: Fix memory leak and use-after-free in os module
  (path_converter).

* bpo-29159: Fix regression in bytes(x) when x.__index__() raises
  Exception.

* bpo-29049: Call _PyObject_GC_TRACK() lazily when calling Python
  function. Calling function is up to 5% faster.

* bpo-28927: bytes.fromhex() and bytearray.fromhex() now ignore all
  ASCII whitespace, not only spaces.  Patch by Robert Xiao.

* bpo-28932: Do not include <sys/random.h> if it does not exist.

* bpo-25677: Correct the positioning of the syntax error caret for
  indented blocks. Based on patch by Michael Layzell.

* bpo-29000: Fixed bytes formatting of octals with zero padding in
  alternate form.

* bpo-18896: Python function can now have more than 255 parameters.
  collections.namedtuple() now supports tuples with more than 255
  elements.

* bpo-28596: The preferred encoding is UTF-8 on Android. Patch
  written by Chi Hsuan Yen.

* bpo-22257: Clean up interpreter startup (see **PEP 432**).

* bpo-26919: On Android, operating system data is now always
  encoded/decoded to/from UTF-8, instead of the locale encoding to
  avoid inconsistencies with os.fsencode() and os.fsdecode() which are
  already using UTF-8.

* bpo-28991: functools.lru_cache() was susceptible to an obscure
  reentrancy bug triggerable by a monkey-patched len() function.

* bpo-28147: Fix a memory leak in split-table dictionaries:
  setattr() must not convert combined table into split table. Patch
  written by INADA Naoki.

* bpo-28739: f-string expressions are no longer accepted as
  docstrings and by ast.literal_eval() even if they do not include
  expressions.

* bpo-28512: Fixed setting the offset attribute of SyntaxError by
  PyErr_SyntaxLocationEx() and PyErr_SyntaxLocationObject().

* bpo-28918: Fix the cross compilation of xxlimited when Python has
  been built with Py_DEBUG defined.

* bpo-23722: Rather than silently producing a class that doesn't
  support zero-argument "super()" in methods, failing to pass the new
  "__classcell__" namespace entry up to "type.__new__" now results in
  a "DeprecationWarning" and a class that supports zero-argument
  "super()".

* bpo-28797: Modifying the class __dict__ inside the __set_name__
  method of a descriptor that is used inside that class no longer
  prevents calling the __set_name__ method of other descriptors.

* bpo-28799: Remove the "PyEval_GetCallStats()" function and
  deprecate the untested and undocumented "sys.callstats()" function.
  Remove the "CALL_PROFILE" special build: use the "sys.setprofile()"
  function, "cProfile" or "profile" to profile function calls.

* bpo-12844: More than 255 arguments can now be passed to a
  function.

* bpo-28782: Fix a bug in the implementation "yield from" when
  checking if the next instruction is YIELD_FROM. Regression
  introduced by WORDCODE (bpo-26647).

* bpo-28774: Fix error position of the unicode error in ASCII and
  Latin1 encoders when a string returned by the error handler contains
  multiple non-encodable characters (non-ASCII for the ASCII codec,
  characters out of the U+0000-U+00FF range for Latin1).

* bpo-28731: Optimize _PyDict_NewPresized() to create correct size
  dict. Improve speed of dict literal with constant keys up to 30%.

* bpo-28532: Show sys.version when -V option is supplied twice.

* bpo-27100: The with-statement now checks for __enter__ before it
  checks for __exit__. This gives less confusing error messages when
  both methods are missing. Patch by Jonathan Ellington.

* bpo-28746: Fix the set_inheritable() file descriptor method on
  platforms that do not have the ioctl FIOCLEX and FIONCLEX commands.

* bpo-26920: Fix not getting the locale's charset upon initializing
  the interpreter, on platforms that do not have langinfo.

* bpo-28648: Fixed crash in Py_DecodeLocale() in debug build on Mac
  OS X when decode astral characters.  Patch by Xiang Zhang.

* bpo-28665: Improve speed of the STORE_DEREF opcode by 40%.

* bpo-19398: Extra slash no longer added to sys.path components in
  case of empty compile-time PYTHONPATH components.

* bpo-28621: Sped up converting int to float by reusing faster bits
  counting implementation.  Patch by Adrian Wielgosik.

* bpo-28580: Optimize iterating split table values. Patch by Xiang
  Zhang.

* bpo-28583: PyDict_SetDefault didn't combine split table when
  needed. Patch by Xiang Zhang.

* bpo-28128: Deprecation warning for invalid str and byte escape
  sequences now prints better information about where the error
  occurs. Patch by Serhiy Storchaka and Eric Smith.

* bpo-28509: dict.update() no longer allocate unnecessary large
  memory.

* bpo-28426: Fixed potential crash in PyUnicode_AsDecodedObject() in
  debug build.

* bpo-28517: Fixed of-by-one error in the peephole optimizer that
  caused keeping unreachable code.

* bpo-28214: Improved exception reporting for problematic
  __set_name__ attributes.

* bpo-23782: Fixed possible memory leak in _PyTraceback_Add() and
  exception loss in PyTraceBack_Here().

* bpo-28183: Optimize and cleanup dict iteration.

* bpo-26081: Added C implementation of asyncio.Future. Original
  patch by Yury Selivanov.

* bpo-28379: Added sanity checks and tests for
  PyUnicode_CopyCharacters(). Patch by Xiang Zhang.

* bpo-28376: The type of long range iterator is now registered as
  Iterator. Patch by Oren Milman.

* bpo-28376: Creating instances of range_iterator by calling
  range_iterator type now is disallowed.  Calling iter() on range
  instance is the only way. Patch by Oren Milman.

* bpo-26906: Resolving special methods of uninitialized type now
  causes implicit initialization of the type instead of a fail.

* bpo-18287: PyType_Ready() now checks that tp_name is not NULL.
  Original patch by Niklas Koep.

* bpo-24098: Fixed possible crash when AST is changed in process of
  compiling it.

* bpo-28201: Dict reduces possibility of 2nd conflict in hash table
  when hashes have same lower bits.

* bpo-28350: String constants with null character no longer
  interned.

* bpo-26617: Fix crash when GC runs during weakref callbacks.

* bpo-27942: String constants now interned recursively in tuples and
  frozensets.

* bpo-28289: ImportError.__init__ now resets not specified
  attributes.

* bpo-21578: Fixed misleading error message when ImportError called
  with invalid keyword args.

* bpo-28203: Fix incorrect type in complex(1.0, {2:3}) error
  message. Patch by Soumya Sharma.

* bpo-28086: Single var-positional argument of tuple subtype was
  passed unscathed to the C-defined function.  Now it is converted to
  exact tuple.

* bpo-28214: Now __set_name__ is looked up on the class instead of
  the instance.

* bpo-27955: Fallback on reading /dev/urandom device when the
  getrandom() syscall fails with EPERM, for example when blocked by
  SECCOMP.

* bpo-28192: Don't import readline in isolated mode.

* bpo-27441: Remove some redundant assignments to ob_size in
  longobject.c. Thanks Oren Milman.

* bpo-27222: Clean up redundant code in long_rshift function. Thanks
  Oren Milman.

* Upgrade internal unicode databases to Unicode version 9.0.0.

* bpo-28131: Fix a regression in zipimport's compile_source().
  zipimport should use the same optimization level as the interpreter.

* bpo-28126: Replace Py_MEMCPY with memcpy(). Visual Studio can
  properly optimize memcpy().

* bpo-28120: Fix dict.pop() for splitted dictionary when trying to
  remove a "pending key" (Not yet inserted in split-table). Patch by
  Xiang Zhang.

* bpo-26182: Raise DeprecationWarning when async and await keywords
  are used as variable/attribute/class/function name.

* bpo-26182: Fix a refleak in code that raises DeprecationWarning.

* bpo-28721: Fix asynchronous generators aclose() and athrow() to
  handle StopAsyncIteration propagation properly.

* bpo-26110: Speed-up method calls: add LOAD_METHOD and CALL_METHOD
  opcodes.


库
--

* bpo-31499: xml.etree: Fix a crash when a parser is part of a
  reference cycle.

* bpo-31482: "random.seed()" now works with bytes in version=1

* bpo-28556: typing.get_type_hints now finds the right globalns for
  classes and modules by default (when no "globalns" was specified by
  the caller).

* bpo-28556: Speed improvements to the "typing" module.  Original
  PRs by Ivan Levkivskyi and Mitar.

* bpo-31544: The C accelerator module of ElementTree ignored
  exceptions raised when looking up TreeBuilder target methods in
  XMLParser().

* bpo-31234: socket.create_connection() now fixes manually a
  reference cycle: clear the variable storing the last exception on
  success.

* bpo-31457: LoggerAdapter objects can now be nested.

* bpo-31431: SSLContext.check_hostname now automatically sets
  SSLContext.verify_mode to ssl.CERT_REQUIRED instead of failing with
  a ValueError.

* bpo-31233: socketserver.ThreadingMixIn now keeps a list of non-
  daemonic threads to wait until all these threads complete in
  server_close().

* bpo-28638: Changed the implementation strategy for
  collections.namedtuple() to substantially reduce the use of exec()
  in favor of precomputed methods. As a result, the *verbose*
  parameter and *_source* attribute are no longer supported.  The
  benefits include 1) having a smaller memory footprint for
  applications using multiple named tuples, 2) faster creation of the
  named tuple class (approx 4x to 6x depending on how it is measured),
  and 3) minor speed-ups for instance creation using __new__, _make,
  and _replace.  (The primary patch contributor is Jelle Zijlstra with
  further improvements by INADA Naoki, Serhiy Storchaka, and Raymond
  Hettinger.)

* bpo-31400: Improves SSL error handling to avoid losing error
  numbers.

* bpo-27629: Make return types of SSLContext.wrap_bio() and
  SSLContext.wrap_socket() customizable.

* bpo-28958: ssl.SSLContext() now uses OpenSSL error information
  when a context cannot be instantiated.

* bpo-28182: The SSL module now raises SSLCertVerificationError when
  OpenSSL fails to verify the peer's certificate. The exception
  contains more information about the error.

* bpo-27340: SSLSocket.sendall() now uses memoryview to create
  slices of data. This fixes support for all bytes-like object. It is
  also more efficient and avoids costly copies.

* bpo-14191: A new function
  "argparse.ArgumentParser.parse_intermixed_args" provides the ability
  to parse command lines where there user intermixes options and
  positional arguments.

* bpo-31178: Fix string concatenation bug in rare error path in the
  subprocess module

* bpo-31350: Micro-optimize "asyncio._get_running_loop()" to become
  up to 10% faster.

* bpo-31170: expat: Update libexpat from 2.2.3 to 2.2.4. Fix copying
  of partial characters for UTF-8 input (libexpat bug 115):
  https://github.com/libexpat/libexpat/issues/115

* bpo-29136: Add TLS 1.3 cipher suites and OP_NO_TLSv1_3.

* bpo-1198569: "string.Template" subclasses can optionally define
  "braceidpattern" if they want to specify different placeholder
  patterns inside and outside the braces.  If None (the default) it
  falls back to "idpattern".

* bpo-31326: concurrent.futures.ProcessPoolExecutor.shutdown() now
  explicitly closes the call queue. Moreover, shutdown(wait=True) now
  also join the call queue thread, to prevent leaking a dangling
  thread.

* bpo-27144: The "map()" and "as_completed()" iterators in
  "concurrent.futures" now avoid keeping a reference to yielded
  objects.

* bpo-31281: Fix "fileinput.FileInput(files, inplace=True)" when
  "files" contain "pathlib.Path" objects.

* bpo-10746: Fix ctypes producing wrong **PEP 3118** type codes for
  integer types.

* bpo-27584: "AF_VSOCK" has been added to the socket interface which
  allows communication between virtual machines and their host.

* bpo-22536: The subprocess module now sets the filename when
  FileNotFoundError is raised on POSIX systems due to the executable
  or cwd not being found.

* bpo-29741: Update some methods in the _pyio module to also accept
  integer types. Patch by Oren Milman.

* bpo-31249: concurrent.futures: WorkItem.run() used by
  ThreadPoolExecutor now breaks a reference cycle between an exception
  object and the WorkItem object.

* bpo-31247: xmlrpc.server now explicitly breaks reference cycles
  when using sys.exc_info() in code handling exceptions.

* bpo-23835: configparser: reading defaults in the "ConfigParser()"
  constructor is now using "read_dict()", making its behavior
  consistent with the rest of the parser.  Non-string keys and values
  in the defaults dictionary are now being implicitly converted to
  strings.  Patch by James Tocknell.

* bpo-31238: pydoc: the stop() method of the private ServerThread
  class now waits until DocServer.serve_until_quit() completes and
  then explicitly sets its docserver attribute to None to break a
  reference cycle.

* bpo-5001: Many asserts in "multiprocessing" are now more
  informative, and some error types have been changed to more specific
  ones.

* bpo-31109: Convert zipimport to use Argument Clinic.

* bpo-30102: The ssl and hashlib modules now call
  OPENSSL_add_all_algorithms_noconf() on OpenSSL < 1.1.0. The function
  detects CPU features and enables optimizations on some CPU
  architectures such as POWER8. Patch is based on research from
  Gustavo Serra Scalet.

* bpo-18966: Non-daemonic threads created by a
  multiprocessing.Process are now joined on child exit.

* bpo-31183: "dis" now works with asynchronous generator and
  coroutine objects. Patch by George Collins based on diagnosis by
  Luciano Ramalho.

* bpo-5001: There are a number of uninformative asserts in the
  "multiprocessing" module, as noted in issue 5001. This change fixes
  two of the most potentially problematic ones, since they are in
  error-reporting code, in the
  "multiprocessing.managers.convert_to_error" function. (It also makes
  more informative a ValueError message.) The only potentially
  problematic change is that the AssertionError is now a TypeError;
  however, this should also help distinguish it from an AssertionError
  being *reported* by the function/its caller (such as in issue
  31169). - Patch by Allen W. Smith (drallensmith on github).

* bpo-31185: Fixed miscellaneous errors in asyncio speedup module.

* bpo-31151: socketserver.ForkingMixIn.server_close() now waits
  until all child processes completed to prevent leaking zombie
  processes.

* bpo-31072: Add an "include_file" parameter to
  "zipapp.create_archive()"

* bpo-24700: Optimize array.array comparison. It is now from 10x up
  to 70x faster when comparing arrays holding values of the same
  integer type.

* bpo-31135: ttk: fix the destroy() method of LabeledScale and
  OptionMenu classes. Call the parent destroy() method even if the
  used attribute doesn't exist. The LabeledScale.destroy() method now
  also explicitly clears label and scale attributes to help the
  garbage collector to destroy all widgets.

* bpo-31107: Fix "copyreg._slotnames()" mangled attribute
  calculation for classes whose name begins with an underscore. Patch
  by Shane Harvey.

* bpo-31080: Allow "logging.config.fileConfig" to accept kwargs
  and/or args.

* bpo-30897: "pathlib.Path" objects now include an "is_mount()"
  method (only implemented on POSIX).  This is similar to
  "os.path.ismount(p)". Patch by Cooper Ry Lees.

* bpo-31061: Fixed a crash when using asyncio and threads.

* bpo-30987: Added support for CAN ISO-TP protocol in the socket
  module.

* bpo-30522: Added a "setStream" method to "logging.StreamHandler"
  to allow the stream to be set after creation.

* bpo-30502: Fix handling of long oids in ssl.  Based on patch by
  Christian Heimes.

* bpo-5288: Support tzinfo objects with sub-minute offsets.

* bpo-30919: Fix shared memory performance regression in
  multiprocessing in 3.x. Shared memory used anonymous memory mappings
  in 2.x, while 3.x mmaps actual files. Try to be careful to do as
  little disk I/O as possible.

* bpo-26732: Fix too many fds in processes started with the
  "forkserver" method. A child process would inherit as many fds as
  the number of still-running children.

* bpo-29403: Fix "unittest.mock"'s autospec to not fail on method-
  bound builtin functions.  Patch by Aaron Gallagher.

* bpo-30961: Fix decrementing a borrowed reference in tracemalloc.

* bpo-19896: Fix multiprocessing.sharedctypes to recognize typecodes
  "'q'" and "'Q'".

* bpo-30946: Remove obsolete code in readline module for platforms
  where GNU readline is older than 2.1 or where select() is not
  available.

* bpo-25684: Change "ttk.OptionMenu" radiobuttons to be unique
  across instances of "OptionMenu".

* bpo-30886: Fix multiprocessing.Queue.join_thread(): it now waits
  until the thread completes, even if the thread was started by the
  same process which created the queue.

* bpo-29854: Fix segfault in readline when using readline's history-
  size option.  Patch by Nir Soffer.

* bpo-30794: Added multiprocessing.Process.kill method to terminate
  using the SIGKILL signal on Unix.

* bpo-30319: socket.close() now ignores ECONNRESET error.

* bpo-30828: Fix out of bounds write in
  "asyncio.CFuture.remove_done_callback()".

* bpo-30302: Use keywords in the "repr" of "datetime.timedelta".

* bpo-30807: signal.setitimer() may disable the timer when passed a
  tiny value. Tiny values (such as 1e-6) are valid non-zero values for
  setitimer(), which is specified as taking microsecond-resolution
  intervals. However, on some platform, our conversion routine could
  convert 1e-6 into a zero interval, therefore disabling the timer
  instead of (re-)scheduling it.

* bpo-30441: Fix bug when modifying os.environ while iterating over
  it

* bpo-29585: Avoid importing "sysconfig" from "site" to improve
  startup speed. Python startup is about 5% faster on Linux and 30%
  faster on macOS.

* bpo-29293: Add missing parameter "n" on
  multiprocessing.Condition.notify(). The doc claims
  multiprocessing.Condition behaves like threading.Condition, but its
  notify() method lacked the optional "n" argument (to specify the
  number of sleepers to wake up) that threading.Condition.notify()
  accepts.

* bpo-30532: Fix email header value parser dropping folding white
  space in certain cases.

* bpo-30596: Add a "close()" method to "multiprocessing.Process".

* bpo-9146: Fix a segmentation fault in _hashopenssl when standard
  hash functions such as md5 are not available in the linked OpenSSL
  library.  As in some special FIPS-140 build environments.

* bpo-29169: Update zlib to 1.2.11.

* bpo-30119: ftplib.FTP.putline() now throws ValueError on commands
  that contains CR or LF. Patch by Dong-hee Na.

* bpo-30879: os.listdir() and os.scandir() now emit bytes names when
  called with bytes-like argument.

* bpo-30746: Prohibited the '=' character in environment variable
  names in "os.putenv()" and "os.spawn*()".

* bpo-30664: The description of a unittest subtest now preserves the
  order of keyword arguments of TestCase.subTest().

* bpo-21071: struct.Struct.format type is now "str" instead of
  "bytes".

* bpo-29212: Fix concurrent.futures.thread.ThreadPoolExecutor
  threads to have a non repr() based thread name by default when no
  thread_name_prefix is supplied. They will now identify themselves as
  "ThreadPoolExecutor-y_n".

* bpo-29755: Fixed the lgettext() family of functions in the gettext
  module. They now always return bytes.

* bpo-30616: Functional API of enum allows to create empty enums.
  Patched by Dong-hee Na

* bpo-30038: Fix race condition between signal delivery and wakeup
  file descriptor. Patch by Nathaniel Smith.

* bpo-23894: lib2to3 now recognizes "rb'...'" and "f'...'" strings.

* bpo-24744: pkgutil.walk_packages function now raises ValueError if
  *path* is a string. Patch by Sanyam Khurana.

* bpo-24484: Avoid race condition in multiprocessing cleanup.

* bpo-30589: Fix multiprocessing.Process.exitcode to return the
  opposite of the signal number when the process is killed by a signal
  (instead of 255) when using the "forkserver" method.

* bpo-28994: The traceback no longer displayed for SystemExit raised
  in a callback registered by atexit.

* bpo-30508: Don't log exceptions if Task/Future "cancel()" method
  was called.

* bpo-30645: Fix path calculation in "imp.load_package()", fixing it
  for cases when a package is only shipped with bytecodes. Patch by
  Alexandru Ardelean.

* bpo-11822: The dis.dis() function now is able to disassemble
  nested code objects.

* bpo-30624: selectors does not take KeyboardInterrupt and
  SystemExit into account, leaving a fd in a bad state in case of
  error. Patch by Giampaolo Rodola'.

* bpo-30595: multiprocessing.Queue.get() with a timeout now polls
  its reader in non-blocking mode if it succeeded to acquire the lock
  but the acquire took longer than the timeout.

* bpo-28556: Updates to typing module: Add generic
  AsyncContextManager, add support for ContextManager on all versions.
  Original PRs by Jelle Zijlstra and Ivan Levkivskyi

* bpo-30605: re.compile() no longer raises a BytesWarning when
  compiling a bytes instance with misplaced inline modifier.  Patch by
  Roy Williams.

* bpo-29870: Fix ssl sockets leaks when connection is aborted in
  asyncio/ssl implementation. Patch by Michaël Sghaïer.

* bpo-29743: Closing transport during handshake process leaks open
  socket. Patch by Nikolay Kim

* bpo-27585: Fix waiter cancellation in asyncio.Lock. Patch by
  Mathieu Sornay.

* bpo-30014: modify() method of poll(), epoll() and devpoll() based
  classes of selectors module is around 10% faster.  Patch by
  Giampaolo Rodola'.

* bpo-30418: On Windows, subprocess.Popen.communicate() now also
  ignore EINVAL on stdin.write() if the child process is still running
  but closed the pipe.

* bpo-30463: Addded empty __slots__ to abc.ABC.  This allows
  subclassers to deny __dict__ and __weakref__ creation.  Patch by
  Aaron Hall.

* bpo-30520: Loggers are now pickleable.

* bpo-30557: faulthandler now correctly filters and displays
  exception codes on Windows

* bpo-30526: Add TextIOWrapper.reconfigure() and a
  TextIOWrapper.write_through attribute.

* bpo-30245: Fix possible overflow when organize struct.pack_into
  error message.  Patch by Yuan Liu.

* bpo-30378: Fix the problem that logging.handlers.SysLogHandler
  cannot handle IPv6 addresses.

* bpo-16500: Allow registering at-fork handlers.

* bpo-30470: Deprecate invalid ctypes call protection on Windows.
  Patch by Mariatta Wijaya.

* bpo-30414: multiprocessing.Queue._feed background running thread
  do not break from main loop on exception.

* bpo-30003: Fix handling escape characters in HZ codec.  Based on
  patch by Ma Lin.

* bpo-30149: inspect.signature() now supports callables with
  variable- argument parameters wrapped with partialmethod. Patch by
  Dong-hee Na.

* bpo-30436: importlib.find_spec() raises ModuleNotFoundError
  instead of AttributeError if the specified parent module is not a
  package (i.e. lacks a __path__ attribute).

* bpo-30301: Fix AttributeError when using SimpleQueue.empty() under
  *spawn* and *forkserver* start methods.

* bpo-30375: Warnings emitted when compile a regular expression now
  always point to the line in the user code.  Previously they could
  point into inners of the re module if emitted from inside of groups
  or conditionals.

* bpo-30329: imaplib and poplib now catch the Windows socket
  WSAEINVAL error (code 10022) on shutdown(SHUT_RDWR): An invalid
  operation was attempted. This error occurs sometimes on SSL
  connections.

* bpo-29196: Removed previously deprecated in Python 2.4 classes
  Plist, Dict and _InternalDict in the plistlib module.  Dict values
  in the result of functions readPlist() and readPlistFromBytes() are
  now normal dicts.  You no longer can use attribute access to access
  items of these dictionaries.

* bpo-9850: The "macpath" is now deprecated and will be removed in
  Python 3.8.

* bpo-30299: Compiling regular expression in debug mode on CPython
  now displays the compiled bytecode in human readable form.

* bpo-30048: Fixed "Task.cancel()" can be ignored when the task is
  running coroutine and the coroutine returned without any more
  "await".

* bpo-30266: contextlib.AbstractContextManager now supports anti-
  registration by setting __enter__ = None or __exit__ = None,
  following the pattern introduced in bpo-25958. Patch by Jelle
  Zijlstra.

* bpo-30340: Enhanced regular expressions optimization. This
  increased the performance of matching some patterns up to 25 times.

* bpo-30298: Weaken the condition of deprecation warnings for inline
  modifiers. Now allowed several subsequential inline modifiers at the
  start of the pattern (e.g. "'(?i)(?s)...'").  In verbose mode
  whitespaces and comments now are allowed before and between inline
  modifiers (e.g. "'(?x) (?i) (?s)...'").

* bpo-30285: Optimized case-insensitive matching and searching of
  regular expressions.

* bpo-29990: Fix range checking in GB18030 decoder.  Original patch
  by Ma Lin.

* bpo-29979: rewrite cgi.parse_multipart, reusing the FieldStorage
  class and making its results consistent with those of FieldStorage
  for multipart/form-data requests. Patch by Pierre Quentel.

* bpo-30243: Removed the __init__ methods of _json's scanner and
  encoder. Misusing them could cause memory leaks or crashes.  Now
  scanner and encoder objects are completely initialized in the
  __new__ methods.

* bpo-30215: Compiled regular expression objects with the re.LOCALE
  flag no longer depend on the locale at compile time.  Only the
  locale at matching time affects the result of matching.

* bpo-30185: Avoid KeyboardInterrupt tracebacks in forkserver helper
  process when Ctrl-C is received.

* bpo-30103: binascii.b2a_uu() and uu.encode() now support using
  "'`'" as zero instead of space.

* bpo-28556: Various updates to typing module: add typing.NoReturn
  type, use WrapperDescriptorType, minor bug-fixes.  Original PRs by
  Jim Fasarakis-Hilliard and Ivan Levkivskyi.

* bpo-30205: Fix getsockname() for unbound AF_UNIX sockets on Linux.

* bpo-30228: The seek() and tell() methods of io.FileIO now set the
  internal seekable attribute to avoid one syscall on open() (in
  buffered or text mode).

* bpo-30190: unittest's assertAlmostEqual and assertNotAlmostEqual
  provide a better message in case of failure which includes the
  difference between left and right arguments.  (patch by Giampaolo
  Rodola')

* bpo-30101: Add support for curses.A_ITALIC.

* bpo-29822: inspect.isabstract() now works during
  __init_subclass__. Patch by Nate Soares.

* bpo-29960: Preserve generator state when _random.Random.setstate()
  raises an exception. Patch by Bryan Olson.

* bpo-30070: Fixed leaks and crashes in errors handling in the
  parser module.

* bpo-22352: Column widths in the output of dis.dis() are now
  adjusted for large line numbers and instruction offsets.

* bpo-30061: Fixed crashes in IOBase methods __next__() and
  readlines() when readline() or __next__() respectively return non-
  sizeable object. Fixed possible other errors caused by not checking
  results of PyObject_Size(), PySequence_Size(), or PyMapping_Size().

* bpo-30218: Fix PathLike support for shutil.unpack_archive. Patch
  by Jelle Zijlstra.

* bpo-10076: Compiled regular expression and match objects in the re
  module now support copy.copy() and copy.deepcopy() (they are
  considered atomic).

* bpo-30068: _io._IOBase.readlines will check if it's closed first
  when hint is present.

* bpo-29694: Fixed race condition in pathlib mkdir with flags
  parents=True. Patch by Armin Rigo.

* bpo-29692: Fixed arbitrary unchaining of RuntimeError exceptions
  in contextlib.contextmanager.  Patch by Siddharth Velankar.

* bpo-26187: Test that sqlite3 trace callback is not called multiple
  times when schema is changing.  Indirectly fixed by switching to use
  sqlite3_prepare_v2() in bpo-9303.  Patch by Aviv Palivoda.

* bpo-30017: Allowed calling the close() method of the zip entry
  writer object multiple times.  Writing to a closed writer now always
  produces a ValueError.

* bpo-29998: Pickling and copying ImportError now preserves name and
  path attributes.

* bpo-29995: re.escape() now escapes only regex special characters.

* bpo-29962: Add math.remainder operation, implementing remainder as
  specified in IEEE 754.

* bpo-29649: Improve struct.pack_into() exception messages for
  problems with the buffer size and offset.  Patch by Andrew Nester.

* bpo-29654: Support If-Modified-Since HTTP header (browser cache).
  Patch by Pierre Quentel.

* bpo-29931: Fixed comparison check for ipaddress.ip_interface
  objects. Patch by Sanjay Sundaresan.

* bpo-29953: Fixed memory leaks in the replace() method of datetime
  and time objects when pass out of bound fold argument.

* bpo-29942: Fix a crash in itertools.chain.from_iterable when
  encountering long runs of empty iterables.

* bpo-10030: Sped up reading encrypted ZIP files by 2 times.

* bpo-29204: Element.getiterator() and the html parameter of
  XMLParser() were deprecated only in the documentation (since Python
  3.2 and 3.4 correspondintly). Now using them emits a deprecation
  warning.

* bpo-27863: Fixed multiple crashes in ElementTree caused by race
  conditions and wrong types.

* bpo-25996: Added support of file descriptors in os.scandir() on
  Unix. os.fwalk() is sped up by 2 times by using os.scandir().

* bpo-28699: Fixed a bug in pools in multiprocessing.pool that
  raising an exception at the very first of an iterable may swallow
  the exception or make the program hang. Patch by Davin Potts and
  Xiang Zhang.

* bpo-23890: unittest.TestCase.assertRaises() now manually breaks a
  reference cycle to not keep objects alive longer than expected.

* bpo-29901: The zipapp module now supports general path-like
  objects, not just pathlib.Path.

* bpo-25803: Avoid incorrect errors raised by
  Path.mkdir(exist_ok=True) when the OS gives priority to errors such
  as EACCES over EEXIST.

* bpo-29861: Release references to tasks, their arguments and their
  results as soon as they are finished in multiprocessing.Pool.

* bpo-19930: The mode argument of os.makedirs() no longer affects
  the file permission bits of newly-created intermediate-level
  directories.

* bpo-29884: faulthandler: Restore the old sigaltstack during
  teardown. Patch by Christophe Zeitouny.

* bpo-25455: Fixed crashes in repr of recursive buffered file-like
  objects.

* bpo-29800: Fix crashes in partial.__repr__ if the keys of
  partial.keywords are not strings.  Patch by Michael Seifert.

* bpo-8256: Fixed possible failing or crashing input() if attributes
  "encoding" or "errors" of sys.stdin or sys.stdout are not set or are
  not strings.

* bpo-28692: Using non-integer value for selecting a plural form in
  gettext is now deprecated.

* bpo-26121: Use C library implementation for math functions erf()
  and erfc().

* bpo-29619: os.stat() and os.DirEntry.inode() now convert inode
  (st_ino) using unsigned integers.

* bpo-28298: Fix a bug that prevented array 'Q', 'L' and 'I' from
  accepting big intables (objects that have __int__) as elements.

* bpo-29645: Speed up importing the webbrowser module.
  webbrowser.register() is now thread-safe.

* bpo-28231: The zipfile module now accepts path-like objects for
  external paths.

* bpo-26915: index() and count() methods of collections.abc.Sequence
  now check identity before checking equality when do comparisons.

* bpo-28682: Added support for bytes paths in os.fwalk().

* bpo-29728: Add new "socket.TCP_NOTSENT_LOWAT" (Linux 3.12)
  constant. Patch by Nathaniel J. Smith.

* bpo-29623: Allow use of path-like object as a single argument in
  ConfigParser.read(). Patch by David Ellis.

* bpo-9303: Migrate sqlite3 module to _v2 API.  Patch by Aviv
  Palivoda.

* bpo-28963: Fix out of bound iteration in
  asyncio.Future.remove_done_callback implemented in C.

* bpo-29704: asyncio.subprocess.SubprocessStreamProtocol no longer
  closes before all pipes are closed.

* bpo-29271: Fix Task.current_task and Task.all_tasks implemented in
  C to accept None argument as their pure Python implementation.

* bpo-29703: Fix asyncio to support instantiation of new event loops
  in child processes.

* bpo-29615: SimpleXMLRPCDispatcher no longer chains KeyError (or
  any other exception) to exception(s) raised in the dispatched
  methods. Patch by Petr Motejlek.

* bpo-7769: Method register_function() of
  xmlrpc.server.SimpleXMLRPCDispatcher and its subclasses can now be
  used as a decorator.

* bpo-29376: Fix assertion error in
  threading._DummyThread.is_alive().

* bpo-28624: Add a test that checks that cwd parameter of Popen()
  accepts PathLike objects.  Patch by Sayan Chowdhury.

* bpo-28518: Start a transaction implicitly before a DML statement.
  Patch by Aviv Palivoda.

* bpo-29742: get_extra_info() raises exception if get called on
  closed ssl transport. Patch by Nikolay Kim.

* bpo-16285: urllib.parse.quote is now based on RFC 3986 and hence
  includes '~' in the set of characters that is not quoted by default.
  Patch by Christian Theune and Ratnadeep Debnath.

* bpo-29532: Altering a kwarg dictionary passed to
  functools.partial() no longer affects a partial object after
  creation.

* bpo-29110: Fix file object leak in aifc.open() when file is given
  as a filesystem path and is not in valid AIFF format. Patch by
  Anthony Zhang.

* bpo-22807: Add uuid.SafeUUID and uuid.UUID.is_safe to relay
  information from the platform about whether generated UUIDs are
  generated with a multiprocessing safe method.

* bpo-29576: Improve some deprecations in importlib. Some deprecated
  methods now emit DeprecationWarnings and have better descriptive
  messages.

* bpo-29534: Fixed different behaviour of Decimal.from_float() for
  _decimal and _pydecimal. Thanks Andrew Nester.

* bpo-10379: locale.format_string now supports the 'monetary'
  keyword argument, and locale.format is deprecated.

* bpo-29851: importlib.reload() now raises ModuleNotFoundError if
  the module lacks a spec.

* bpo-28556: Various updates to typing module: typing.Counter,
  typing.ChainMap, improved ABC caching, etc. Original PRs by Jelle
  Zijlstra, Ivan Levkivskyi, Manuel Krebber, and Łukasz Langa.

* bpo-29100: Fix datetime.fromtimestamp() regression introduced in
  Python 3.6.0: check minimum and maximum years.

* bpo-29416: Prevent infinite loop in pathlib.Path.mkdir

* bpo-29444: Fixed out-of-bounds buffer access in the group() method
  of the match object. Based on patch by WGH.

* bpo-29377: Add WrapperDescriptorType, MethodWrapperType, and
  MethodDescriptorType built-in types to types module. Original patch
  by Manuel Krebber.

* bpo-29218: Unused install_misc command is now removed.  It has
  been documented as unused since 2000.  Patch by Eric N. Vander
  Weele.

* bpo-29368: The extend() method is now called instead of the
  append() method when unpickle collections.deque and other list-like
  objects. This can speed up unpickling to 2 times.

* bpo-29338: The help of a builtin or extension class now includes
  the constructor signature if __text_signature__ is provided for the
  class.

* bpo-29335: Fix subprocess.Popen.wait() when the child process has
  exited to a stopped instead of terminated state (ex: when under
  ptrace).

* bpo-29290: Fix a regression in argparse that help messages would
  wrap at non-breaking spaces.

* bpo-28735: Fixed the comparison of mock.MagickMock with mock.ANY.

* bpo-29197: Removed deprecated function ntpath.splitunc().

* bpo-29210: Removed support of deprecated argument "exclude" in
  tarfile.TarFile.add().

* bpo-29219: Fixed infinite recursion in the repr of uninitialized
  ctypes.CDLL instances.

* bpo-29192: Removed deprecated features in the http.cookies module.

* bpo-29193: A format string argument for string.Formatter.format()
  is now positional-only.

* bpo-29195: Removed support of deprecated undocumented keyword
  arguments in methods of regular expression objects.

* bpo-28969: Fixed race condition in C implementation of
  functools.lru_cache. KeyError could be raised when cached function
  with full cache was simultaneously called from different threads
  with the same uncached arguments.

* bpo-20804: The unittest.mock.sentinel attributes now preserve
  their identity when they are copied or pickled.

* bpo-29142: In urllib.request, suffixes in no_proxy environment
  variable with leading dots could match related hostnames again (e.g.
  .b.c matches a.b.c). Patch by Milan Oberkirch.

* bpo-28961: Fix unittest.mock._Call helper: don't ignore the name
  parameter anymore. Patch written by Jiajun Huang.

* bpo-15812: inspect.getframeinfo() now correctly shows the first
  line of a context. Patch by Sam Breese.

* bpo-28985: Update authorizer constants in sqlite3 module. Patch by
  Dingyuan Wang.

* bpo-29079: Prevent infinite loop in pathlib.resolve() on Windows

* bpo-13051: Fixed recursion errors in large or resized
  curses.textpad.Textbox.  Based on patch by Tycho Andersen.

* bpo-9770: curses.ascii predicates now work correctly with negative
  integers.

* bpo-28427: old keys should not remove new values from
  WeakValueDictionary when collecting from another thread.

* bpo-28923: Remove editor artifacts from Tix.py.

* bpo-28871: Fixed a crash when deallocate deep ElementTree.

* bpo-19542: Fix bugs in WeakValueDictionary.setdefault() and
  WeakValueDictionary.pop() when a GC collection happens in another
  thread.

* bpo-20191: Fixed a crash in resource.prlimit() when passing a
  sequence that doesn't own its elements as limits.

* bpo-16255: subprocess.Popen uses /system/bin/sh on Android as the
  shell, instead of /bin/sh.

* bpo-28779: multiprocessing.set_forkserver_preload() would crash
  the forkserver process if a preloaded module instantiated some
  multiprocessing objects such as locks.

* bpo-26937: The chown() method of the tarfile.TarFile class does
  not fail now when the grp module cannot be imported, as for example
  on Android platforms.

* bpo-28847: dbm.dumb now supports reading read-only files and no
  longer writes the index file when it is not changed.  A deprecation
  warning is now emitted if the index file is missed and recreated in
  the 'r' and 'w' modes (will be an error in future Python releases).

* bpo-27030: Unknown escapes consisting of "'\'" and an ASCII letter
  in re.sub() replacement templates regular expressions now are
  errors.

* bpo-28835: Fix a regression introduced in
  warnings.catch_warnings(): call warnings.showwarning() if it was
  overridden inside the context manager.

* bpo-27172: To assist with upgrades from 2.7, the previously
  documented deprecation of "inspect.getfullargspec()" has been
  reversed. This decision may be revisited again after the Python 2.7
  branch is no longer officially supported.

* bpo-28740: Add sys.getandroidapilevel(): return the build time API
  version of Android as an integer. Function only available on
  Android.

* bpo-26273: Add new "socket.TCP_CONGESTION" (Linux 2.6.13) and
  "socket.TCP_USER_TIMEOUT" (Linux 2.6.37) constants. Patch written by
  Omar Sandoval.

* bpo-28752: Restored the __reduce__() methods of datetime objects.

* bpo-28727: Regular expression patterns, _sre.SRE_Pattern objects
  created by re.compile(), become comparable (only x==y and x!=y
  operators). This change should fix the bpo-18383: don't duplicate
  warning filters when the warnings module is reloaded (thing usually
  only done in unit tests).

* bpo-20572: Remove the subprocess.Popen.wait endtime parameter.  It
  was deprecated in 3.4 and undocumented prior to that.

* bpo-25659: In ctypes, prevent a crash calling the from_buffer()
  and from_buffer_copy() methods on abstract classes like Array.

* bpo-28548: In the "http.server" module, parse the protocol version
  if possible, to avoid using HTTP 0.9 in some error responses.

* bpo-19717: Makes Path.resolve() succeed on paths that do not
  exist. Patch by Vajrasky Kok

* bpo-28563: Fixed possible DoS and arbitrary code execution when
  handle plural form selections in the gettext module.  The expression
  parser now supports exact syntax supported by GNU gettext.

* bpo-28387: Fixed possible crash in _io.TextIOWrapper deallocator
  when the garbage collector is invoked in other thread.  Based on
  patch by Sebastian Cufre.

* bpo-27517: LZMA compressor and decompressor no longer raise
  exceptions if given empty data twice.  Patch by Benjamin Fogle.

* bpo-28549: Fixed segfault in curses's addch() with ncurses6.

* bpo-28449: tarfile.open() with mode "r" or "r:" now tries to open
  a tar file with compression before trying to open it without
  compression. Otherwise it had 50% chance failed with
  ignore_zeros=True.

* bpo-23262: The webbrowser module now supports Firefox 36+ and
  derived browsers.  Based on patch by Oleg Broytman.

* bpo-24241: The webbrowser in an X environment now prefers using
  the default browser directly. Also, the webbrowser register()
  function now has a documented 'preferred' argument, to specify
  browsers to be returned by get() with no arguments. Patch by David
  Steele

* bpo-27939: Fixed bugs in tkinter.ttk.LabeledScale and
  tkinter.Scale caused by representing the scale as float value
  internally in Tk. tkinter.IntVar now works if float value is set to
  underlying Tk variable.

* bpo-28255: calendar.TextCalendar.prweek() no longer prints a space
  after a weeks's calendar.  calendar.TextCalendar.pryear() no longer
  prints redundant newline after a year's calendar.  Based on patch by
  Xiang Zhang.

* bpo-28255: calendar.TextCalendar.prmonth() no longer prints a
  space at the start of new line after printing a month's calendar.
  Patch by Xiang Zhang.

* bpo-20491: The textwrap.TextWrapper class now honors non-breaking
  spaces. Based on patch by Kaarle Ritvanen.

* bpo-28353: os.fwalk() no longer fails on broken links.

* bpo-28430: Fix iterator of C implemented asyncio.Future doesn't
  accept non-None value is passed to it.send(val).

* bpo-27025: Generated names for Tkinter widgets now start by the
  "!" prefix for readability.

* bpo-25464: Fixed HList.header_exists() in tkinter.tix module by
  addin a workaround to Tix library bug.

* bpo-28488: shutil.make_archive() no longer adds entry "./" to ZIP
  archive.

* bpo-25953: re.sub() now raises an error for invalid numerical
  group reference in replacement template even if the pattern is not
  found in the string.  Error message for invalid group reference now
  includes the group index and the position of the reference. Based on
  patch by SilentGhost.

* bpo-28469: timeit now uses the sequence 1, 2, 5, 10, 20, 50,...
  instead of 1, 10, 100,... for autoranging.

* bpo-28115: Command-line interface of the zipfile module now uses
  argparse. Added support of long options.

* bpo-18219: Optimize csv.DictWriter for large number of columns.
  Patch by Mariatta Wijaya.

* bpo-28448: Fix C implemented asyncio.Future didn't work on
  Windows.

* bpo-23214: In the "io" module, the argument to BufferedReader and
  BytesIO's read1() methods is now optional and can be -1, matching
  the BufferedIOBase specification.

* bpo-28480: Fix error building socket module when multithreading is
  disabled.

* bpo-28240: timeit: remove "-c/--clock" and "-t/--time" command
  line options which were deprecated since Python 3.3.

* bpo-28240: timeit now repeats the benchmarks 5 times instead of
  only 3 to make benchmarks more reliable.

* bpo-28240: timeit autorange now uses a single loop iteration if
  the benchmark takes less than 10 seconds, instead of 10 iterations.
  "python3 -m timeit -s 'import time' 'time.sleep(1)'" now takes 4
  seconds instead of 40 seconds.

* Distutils.sdist now looks for README and setup.py files with case
  sensitivity. This behavior matches that found in Setuptools 6.0 and
  later. See setuptools 100 for rationale.

* bpo-24452: Make webbrowser support Chrome on Mac OS X. Patch by
  Ned Batchelder.

* bpo-20766: Fix references leaked by pdb in the handling of SIGINT
  handlers.

* bpo-27998: Fixed bytes path support in os.scandir() on Windows.
  Patch by Eryk Sun.

* bpo-28317: The disassembler now decodes FORMAT_VALUE argument.

* bpo-28380: unittest.mock Mock autospec functions now properly
  support assert_called, assert_not_called, and assert_called_once.

* bpo-28229: lzma module now supports pathlib.

* bpo-28321: Fixed writing non-BMP characters with binary format in
  plistlib.

* bpo-28225: bz2 module now supports pathlib.  Initial patch by
  Ethan Furman.

* bpo-28227: gzip now supports pathlib.  Patch by Ethan Furman.

* bpo-28332: Deprecated silent truncations in socket.htons and
  socket.ntohs. Original patch by Oren Milman.

* bpo-27358: Optimized merging var-keyword arguments and improved
  error message when passing a non-mapping as a var-keyword argument.

* bpo-28257: Improved error message when passing a non-iterable as a
  var-positional argument.  Added opcode BUILD_TUPLE_UNPACK_WITH_CALL.

* bpo-28322: Fixed possible crashes when unpickle itertools objects
  from incorrect pickle data.  Based on patch by John Leitch.

* bpo-28228: imghdr now supports pathlib.

* bpo-28226: compileall now supports pathlib.

* bpo-28314: Fix function declaration (C flags) for the
  getiterator() method of xml.etree.ElementTree.Element.

* bpo-28148: Stop using localtime() and gmtime() in the time module.
  Introduced platform independent _PyTime_localtime API that is
  similar to POSIX localtime_r, but available on all platforms.  Patch
  by Ed Schouten.

* bpo-28253: Fixed calendar functions for extreme months: 0001-01
  and 9999-12. Methods itermonthdays() and itermonthdays2() are
  reimplemented so that they don't call itermonthdates() which can
  cause datetime.date under/overflow.

* bpo-28275: Fixed possible use after free in the decompress()
  methods of the LZMADecompressor and BZ2Decompressor classes.
  Original patch by John Leitch.

* bpo-27897: Fixed possible crash in
  sqlite3.Connection.create_collation() if pass invalid string-like
  object as a name.  Patch by Xiang Zhang.

* bpo-18844: random.choices() now has k as a keyword-only argument
  to improve the readability of common cases and come into line with
  the signature used in other languages.

* bpo-18893: Fix invalid exception handling in
  Lib/ctypes/macholib/dyld.py. Patch by Madison May.

* bpo-27611: Fixed support of default root window in the tkinter.tix
  module. Added the master parameter in the DisplayStyle constructor.

* bpo-27348: In the traceback module, restore the formatting of
  exception messages like "Exception: None".  This fixes a regression
  introduced in 3.5a2.

* bpo-25651: Allow falsy values to be used for msg parameter of
  subTest().

* bpo-27778: Fix a memory leak in os.getrandom() when the
  getrandom() is interrupted by a signal and a signal handler raises a
  Python exception.

* bpo-28200: Fix memory leak on Windows in the os module (fix
  path_converter() function).

* bpo-25400: RobotFileParser now correctly returns default values
  for crawl_delay and request_rate.  Initial patch by Peter Wirtz.

* bpo-27932: Prevent memory leak in win32_ver().

* Fix UnboundLocalError in socket._sendfile_use_sendfile.

* bpo-28075: Check for ERROR_ACCESS_DENIED in Windows implementation
  of os.stat().  Patch by Eryk Sun.

* bpo-22493: Warning message emitted by using inline flags in the
  middle of regular expression now contains a (truncated) regex
  pattern. Patch by Tim Graham.

* bpo-25270: Prevent codecs.escape_encode() from raising SystemError
  when an empty bytestring is passed.

* bpo-28181: Get antigravity over HTTPS. Patch by Kaartic Sivaraam.

* bpo-25895: Enable WebSocket URL schemes in urllib.parse.urljoin.
  Patch by Gergely Imreh and Markus Holtermann.

* bpo-28114: Fix a crash in parse_envlist() when env contains byte
  strings. Patch by Eryk Sun.

* bpo-27599: Fixed buffer overrun in binascii.b2a_qp() and
  binascii.a2b_qp().

* bpo-27906: Fix socket accept exhaustion during high TCP traffic.
  Patch by Kevin Conway.

* bpo-28174: Handle when SO_REUSEPORT isn't properly supported.
  Patch by Seth Michael Larson.

* bpo-26654: Inspect functools.partial in asyncio.Handle.__repr__.
  Patch by iceboy.

* bpo-26909: Fix slow pipes IO in asyncio. Patch by INADA Naoki.

* bpo-28176: Fix callbacks race in
  asyncio.SelectorLoop.sock_connect.

* bpo-27759: Fix selectors incorrectly retain invalid file
  descriptors. Patch by Mark Williams.

* bpo-28325: Remove vestigial MacOS 9 macurl2path module and its
  tests.

* bpo-28368: Refuse monitoring processes if the child watcher has no
  loop attached. Patch by Vincent Michel.

* bpo-28369: Raise RuntimeError when transport's FD is used with
  add_reader, add_writer, etc.

* bpo-28370: Speedup asyncio.StreamReader.readexactly. Patch by
  Коренберг Марк.

* bpo-28371: Deprecate passing asyncio.Handles to run_in_executor.

* bpo-28372: Fix asyncio to support formatting of non-python
  coroutines.

* bpo-28399: Remove UNIX socket from FS before binding. Patch by
  Коренберг Марк.

* bpo-27972: Prohibit Tasks to await on themselves.

* bpo-24142: Reading a corrupt config file left configparser in an
  invalid state. Original patch by Florian Höch.

* bpo-29581: ABCMeta.__new__ now accepts "**kwargs", allowing
  abstract base classes to use keyword parameters in
  __init_subclass__. Patch by Nate Soares.

* bpo-25532: inspect.unwrap() will now only try to unwrap an object
  sys.getrecursionlimit() times, to protect against objects which
  create a new object on every attribute access.

* bpo-30177: path.resolve(strict=False) no longer cuts the path
  after the first element not present in the filesystem.  Patch by
  Antoine Pietri.


文档
----

* bpo-31294: Fix incomplete code snippet in the ZeroMQSocketListener
  and ZeroMQSocketHandler examples and adapt them to Python 3.

* bpo-21649: Add RFC 7525 and Mozilla server side TLS links to SSL
  documentation.

* bpo-31128: Allow the pydoc server to bind to arbitrary hostnames.

* bpo-30803: Clarify doc on truth value testing. Original patch by
  Peter Thomassen.

* bpo-30176: Add missing attribute related constants in curses
  documentation.

* bpo-30052: the link targets for "bytes()" and "bytearray()" are
  now their respective type definitions, rather than the corresponding
  builtin function entries. Use bytes and bytearray to reference the
  latter. In order to ensure this and future cross-reference updates
  are applied automatically, the daily documentation builds now
  disable the default output caching features in Sphinx.

* bpo-26985: Add missing info of code object in inspect
  documentation.

* bpo-19824: Improve the documentation for, and links to, template
  strings by emphasizing their utility for internationalization, and
  by clarifying some usage constraints. (See also: bpo-20314,
  bpo-12518)

* bpo-28929: Link the documentation to its source file on GitHub.

* bpo-25008: Document smtpd.py as effectively deprecated and add a
  pointer to aiosmtpd, a third-party asyncio-based replacement.

* bpo-26355: Add canonical header link on each page to corresponding
  major version of the documentation. Patch by Matthias Bussonnier.

* bpo-29349: Fix Python 2 syntax in code for building the
  documentation.

* bpo-23722: The data model reference and the porting section in the
  3.6 What's New guide now cover the additional "__classcell__"
  handling needed for custom metaclasses to fully support **PEP 487**
  and zero-argument "super()".

* bpo-28513: Documented command-line interface of zipfile.


测试
----

* bpo-29639: test.support.HOST is now "localhost", a new HOSTv4
  constant has been added for your "127.0.0.1" needs, similar to the
  existing HOSTv6 constant.

* bpo-31320: Silence traceback in test_ssl

* bpo-31346: Prefer PROTOCOL_TLS_CLIENT and PROTOCOL_TLS_SERVER
  protocols for SSLContext.

* bpo-25674: Remove sha256.tbs-internet.com ssl test

* bpo-30715: Address ALPN callback changes for OpenSSL 1.1.0f. The
  latest version behaves like OpenSSL 1.0.2 and no longer aborts
  handshake.

* bpo-30822: regrtest: Exclude tzdata from regrtest --all. When
  running the test suite using --use=all / -u all, exclude tzdata
  since it makes test_datetime too slow (15-20 min on some buildbots)
  which then times out on some buildbots. Fix also regrtest command
  line parser to allow passing -u extralargefile to run
  test_zipfile64.

* bpo-30695: Add the "set_nomemory(start, stop)" and
  "remove_mem_hooks()" functions to the _testcapi module.

* bpo-30357: test_thread: setUp() now uses support.threading_setup()
  and support.threading_cleanup() to wait until threads complete to
  avoid random side effects on following tests. Initial patch written
  by Grzegorz Grzywacz.

* bpo-30197: Enhanced functions swap_attr() and swap_item() in the
  test.support module. They now work when delete replaced attribute or
  item inside the with statement.  The old value of the attribute or
  item (or None if it doesn't exist) now will be assigned to the
  target of the "as" clause, if there is one.

* bpo-24932: Use proper command line parsing in _testembed

* bpo-28950: Disallow -j0 to be combined with -T/-l in regrtest
  command line arguments.

* bpo-28683: Fix the tests that bind() a unix socket and raise
  PermissionError on Android for a non-root user.

* bpo-26936: Fix the test_socket failures on Android -
  getservbyname(), getservbyport() and getaddrinfo() are broken on
  some Android API levels.

* bpo-28666: Now test.support.rmtree is able to remove unwritable or
  unreadable directories.

* bpo-23839: Various caches now are cleared before running every
  test file.

* bpo-26944: Fix test_posix for Android where 'id -G' is entirely
  wrong or missing the effective gid.

* bpo-28409: regrtest: fix the parser of command line arguments.

* bpo-28217: Adds _testconsole module to test console input.

* bpo-26939: Add the support.setswitchinterval() function to fix
  test_functools hanging on the Android armv7 qemu emulator.


构建
----

* bpo-31354: Allow --with-lto to be used on all builds, not just
  "make profile-opt".

* bpo-31370: Remove support for building --without-threads. This
  option is not really useful anymore in the 21st century. Removing
  lots of conditional paths allows us to simplify the code base,
  including in difficult to maintain low-level internal code.

* bpo-31341: Per **PEP 11**, support for the IRIX operating system
  was removed.

* bpo-30854: Fix compile error when compiling --without-threads.
  Patch by Masayuki Yamamoto.

* bpo-30687: Locate msbuild.exe on Windows when building rather than
  vcvarsall.bat

* bpo-20210: Support the *disabled* marker in Setup files. Extension
  modules listed after this marker are not built at all, neither by
  the Makefile nor by setup.py.

* bpo-29941: Add "--with-assertions" configure flag to explicitly
  enable C "assert()" checks. Defaults to off. "--with-pydebug"
  implies "--with-assertions".

* bpo-28787: Fix out-of-tree builds of Python when configured with
  "-- with--dtrace".

* bpo-29243: Prevent unnecessary rebuilding of Python during "make
  test", "make install" and some other make targets when configured
  with "--enable-optimizations".

* bpo-23404: Don't regenerate generated files based on file
  modification time anymore: the action is now explicit. Replace "make
  touch" with "make regen-all".

* bpo-29643: Fix "--enable-optimization" didn't work.

* bpo-27593: sys.version and the platform module python_build(),
  python_branch(), and python_revision() functions now use git
  information rather than hg when building from a repo.

* bpo-29572: Update Windows build and OS X installers to use OpenSSL
  1.0.2k.

* bpo-27659: Prohibit implicit C function declarations: use "-Werror
  =implicit-function-declaration" when possible (GCC and Clang, but it
  depends on the compiler version). Patch written by Chi Hsuan Yen.

* bpo-29384: Remove old Be OS helper scripts.

* bpo-26851: Set Android compilation and link flags.

* bpo-28768: Fix implicit declaration of function _setmode. Patch by
  Masayuki Yamamoto

* bpo-29080: Removes hard dependency on hg.exe from
  PCBuild/build.bat

* bpo-23903: Added missed names to PC/python3.def.

* bpo-28762: lockf() is available on Android API level 24, but the
  F_LOCK macro is not defined in android-ndk-r13.

* bpo-28538: Fix the compilation error that occurs because
  if_nameindex() is available on Android API level 24, but the
  if_nameindex structure is not defined.

* bpo-20211: Do not add the directory for installing C header files
  and the directory for installing object code libraries to the cross
  compilation search paths. Original patch by Thomas Petazzoni.

* bpo-28849: Do not define sys.implementation._multiarch on Android.

* bpo-10656: Fix out-of-tree building on AIX.  Patch by Tristan
  Carel and Michael Haubenwallner.

* bpo-26359: Rename --with-optimiations to --enable-optimizations.

* bpo-28444: Fix missing extensions modules when cross compiling.

* bpo-28208: Update Windows build and OS X installers to use SQLite
  3.14.2.

* bpo-28248: Update Windows build and OS X installers to use OpenSSL
  1.0.2j.

* bpo-21124: Fix building the _struct module on Cygwin by passing
  "NULL" instead of "&PyType_Type" to PyVarObject_HEAD_INIT.  Patch by
  Masayuki Yamamoto.

* bpo-13756: Fix building extensions modules on Cygwin.  Patch by
  Roumen Petrov, based on original patch by Jason Tishler.

* bpo-21085: Add configure check for siginfo_t.si_band, which Cygwin
  does not provide. Patch by Masayuki Yamamoto with review and rebase
  by Erik Bray.

* bpo-28258: Fixed build with Estonian locale (python-config and
  distclean targets in Makefile).  Patch by Arfrever Frehtes Taifersar
  Arahesis.

* bpo-26661: setup.py now detects system libffi with multiarch
  wrapper.

* bpo-27979: A full copy of libffi is no longer bundled for use when
  building _ctypes on non-OSX UNIX platforms.  An installed copy of
  libffi is now required when building _ctypes on such platforms.

* bpo-15819: Remove redundant include search directory option for
  building outside the source tree.

* bpo-28676: Prevent missing 'getentropy' declaration warning on
  macOS. Patch by Gareth Rees.


Windows
-------

* bpo-31392: Update Windows build to use OpenSSL 1.1.0f

* bpo-30389: Adds detection of Visual Studio 2017 to distutils on
  Windows.

* bpo-31358: zlib is no longer bundled in the CPython source,
  instead it is downloaded on demand just like bz2, lzma, OpenSSL,
  Tcl/Tk, and SQLite.

* bpo-31340: Change to building with MSVC v141 (included with Visual
  Studio 2017)

* bpo-30581: os.cpu_count() now returns the correct number of
  processors on Windows when the number of logical processors is
  greater than 64.

* bpo-30916: Pre-build OpenSSL, Tcl and Tk and include the binaries
  in the build.

* bpo-30731: Add a missing xmlns to python.manifest so that it
  matches the schema.

* bpo-30291: Allow requiring 64-bit interpreters from py.exe using
  -64 suffix. Contributed by Steve (Gadget) Barnes.

* bpo-30362: Adds list options (-0, -0p) to py.exe launcher.
  Contributed by Steve Barnes.

* bpo-23451: Fix socket deprecation warnings in socketmodule.c.
  Patch by Segev Finer.

* bpo-30450: The build process on Windows no longer depends on
  Subversion, instead pulling external code from GitHub via a Python
  script.  If Python 3.6 is not found on the system (via "py -3.6"),
  NuGet is used to download a copy of 32-bit Python.

* bpo-29579: Removes readme.txt from the installer.

* bpo-25778: winreg does not truncate string correctly (Patch by
  Eryk Sun)

* bpo-28896: Deprecate WindowsRegistryFinder and disable it by
  default

* bpo-28522: Fixes mishandled buffer reallocation in getpathp.c

* bpo-28402: Adds signed catalog files for stdlib on Windows.

* bpo-28333: Enables Unicode for ps1/ps2 and input() prompts. (Patch
  by Eryk Sun)

* bpo-28251: Improvements to help manuals on Windows.

* bpo-28110: launcher.msi has different product codes between 32-bit
  and 64-bit

* bpo-28161: Opening CON for write access fails

* bpo-28162: WindowsConsoleIO readall() fails if first line starts
  with Ctrl+Z

* bpo-28163: WindowsConsoleIO fileno() passes wrong flags to
  _open_osfhandle

* bpo-28164: _PyIO_get_console_type fails for various paths

* bpo-28137: Renames Windows path file to ._pth

* bpo-28138: Windows ._pth file should allow import site


IDLE
----

* bpo-31493: IDLE code context -- fix code update and font update
  timers. Canceling timers prevents a warning message when test_idle
  completes.

* bpo-31488: IDLE - Update non-key options in former extension
  classes. When applying configdialog changes, call .reload for each
  feature class. Change ParenMatch so updated options affect existing
  instances attached to existing editor windows.

* bpo-31477: IDLE - Improve rstrip entry in doc. Strip trailing
  whitespace strips more than blank spaces.  Multiline string literals
  are not skipped.

* bpo-31480: IDLE - make tests pass with zzdummy extension disabled
  by default.

* bpo-31421: Document how IDLE runs tkinter programs. IDLE calls
  tcl/tk update in the background in order to make live interaction
  and experimentation with tkinter applications much easier.

* bpo-31414: IDLE -- fix tk entry box tests by deleting first.
  Adding to an int entry is not the same as deleting and inserting
  because int('') will fail.

* bpo-31051: Rearrange IDLE configdialog GenPage into Window,
  Editor, and Help sections.

* bpo-30617: IDLE - Add docstrings and tests for outwin subclass of
  editor. Move some data and functions from the class to module level.
  Patch by Cheryl Sabella.

* bpo-31287: IDLE - Do not modify tkinter.message in
  test_configdialog.

* bpo-27099: Convert IDLE's built-in 'extensions' to regular
  features. About 10 IDLE features were implemented as supposedly
  optional extensions. Their different behavior could be confusing or
  worse for users and not good for maintenance. Hence the conversion.
  The main difference for users is that user configurable key bindings
  for builtin features are now handled uniformly. Now, editing a
  binding in a keyset only affects its value in the keyset. All
  bindings are defined together in the system-specific default keysets
  in config- extensions.def. All custom keysets are saved as a whole
  in config- extension.cfg.  All take effect as soon as one clicks
  Apply or Ok. The affected events are '<<force-open-completions>>',
  '<<expand- word>>', '<<force-open-calltip>>', '<<flash-paren>>',
  '<<format- paragraph>>', '<<run-module>>', '<<check-module>>', and
  '<<zoom- height>>'.  Any (global) customizations made before 3.6.3
  will not affect their keyset-specific customization after 3.6.3. and
  vice versa. Initial patch by Charles Wohlganger.

* bpo-31206: IDLE: Factor HighPage(Frame) class from ConfigDialog.
  Patch by Cheryl Sabella.

* bpo-31001: Add tests for configdialog highlight tab.  Patch by
  Cheryl Sabella.

* bpo-31205: IDLE: Factor KeysPage(Frame) class from ConfigDialog.
  The slightly modified tests continue to pass.  Patch by Cheryl
  Sabella.

* bpo-31130: IDLE -- stop leaks in test_configdialog. Initial patch
  by Victor Stinner.

* bpo-31002: Add tests for configdialog keys tab. Patch by Cheryl
  Sabella.

* bpo-19903: IDLE: Calltips use "inspect.signature" instead of
  "inspect.getfullargspec". This improves calltips for builtins
  converted to use Argument Clinic. Patch by Louie Lu.

* bpo-31083: IDLE - Add an outline of a TabPage class in
  configdialog. Update existing classes to match outline. Initial
  patch by Cheryl Sabella.

* bpo-31050: Factor GenPage(Frame) class from ConfigDialog. The
  slightly modified tests continue to pass. Patch by Cheryl Sabella.

* bpo-31004: IDLE - Factor FontPage(Frame) class from ConfigDialog.
  Slightly modified tests continue to pass. Fix General tests. Patch
  mostly by Cheryl Sabella.

* bpo-30781: IDLE - Use ttk widgets in ConfigDialog. Patches by
  Terry Jan Reedy and Cheryl Sabella.

* bpo-31060: IDLE - Finish rearranging methods of ConfigDialog
  Grouping methods pertaining to each tab and the buttons will aid
  writing tests and improving the tabs and will enable splitting the
  groups into classes.

* bpo-30853: IDLE -- Factor a VarTrace class out of ConfigDialog.
  Instance tracers manages pairs consisting of a tk variable and a
  callback function. When tracing is turned on, setting the variable
  calls the function.  Test coverage for the new class is 100%.

* bpo-31003: IDLE: Add more tests for General tab.

* bpo-30993: IDLE - Improve configdialog font page and tests. In
  configdialog: Document causal pathways in create_font_tab docstring.
  Simplify some attribute names. Move set_samples calls to
  var_changed_font (idea from Cheryl Sabella).  Move related functions
  to positions after the create widgets function. In
  test_configdialog: Fix test_font_set so not order dependent.  Fix
  renamed test_indent_scale so it tests the widget. Adjust tests for
  movement of set_samples call.  Add tests for load functions.  Put
  all font tests in one class and tab indent tests in another.  Except
  for two lines, these tests completely cover the related functions.

* bpo-30981: IDLE -- Add more configdialog font page tests.

* bpo-28523: IDLE: replace 'colour' with 'color' in configdialog.

* bpo-30917: Add tests for idlelib.config.IdleConf. Increase
  coverage from 46% to 96%. Patch by Louie Lu.

* bpo-30934: Document coverage details for idlelib tests. Add
  section to idlelib/idle-test/README.txt. Include check that branches
  are taken both ways. Exclude IDLE-specific code that does not run
  during unit tests.

* bpo-30913: IDLE: Document ConfigDialog tk Vars, methods, and
  widgets in docstrings This will facilitate improving the dialog and
  splitting up the class. Original patch by Cheryl Sabella.

* bpo-30899: IDLE: Add tests for ConfigParser subclasses in config.
  Patch by Louie Lu.

* bpo-30881: IDLE: Add docstrings to browser.py. Patch by Cheryl
  Sabella.

* bpo-30851: IDLE: Remove unused variables in configdialog.  One is
  a duplicate, one is set but cannot be altered by users. Patch by
  Cheryl Sabella.

* bpo-30870: IDLE: In Settings dialog, select font with Up, Down
  keys as well as mouse. Initial patch by Louie Lu.

* bpo-8231: IDLE: call config.IdleConf.GetUserCfgDir only once.

* bpo-30779: IDLE: Factor ConfigChanges class from configdialog, put
  in config; test. * In config, put dump test code in a function; run
  it and unittest in   'if __name__ == '__main__'. * Add class
  config.ConfigChanges based on changes_class_v4.py on bpo issue. *
  Add class test_config.ChangesTest, partly using
  configdialog_tests_v1.py. * Revise configdialog to use
  ConfigChanges; see tracker msg297804. * Revise test_configdialog to
  match configdialog changes. * Remove configdialog functions unused
  or moved to ConfigChanges. Cheryl Sabella contributed parts of the
  patch.

* bpo-30777: IDLE: configdialog - Add docstrings and fix comments.
  Patch by Cheryl Sabella.

* bpo-30495: IDLE: Improve textview with docstrings, PEP8 names, and
  more tests. Patch by Cheryl Sabella.

* bpo-30723: IDLE: Make several improvements to parenmatch. Add
  'parens' style to highlight both opener and closer. Make 'default'
  style, which is not default, a synonym for 'opener'. Make time-delay
  work the same with all styles. Add help for config dialog extensions
  tab, including help for parenmatch. Add new tests.  Original patch
  by Charles Wohlganger.

* bpo-30674: IDLE: add docstrings to grep module. Patch by Cheryl
  Sabella

* bpo-21519: IDLE's basic custom key entry dialog now detects
  duplicates properly. Original patch by Saimadhav Heblikar.

* bpo-29910: IDLE no longer deletes a character after commenting out
  a region by a key shortcut.  Add "return 'break'" for this and other
  potential conflicts between IDLE and default key bindings.

* bpo-30728: Review and change idlelib.configdialog names. Lowercase
  method and attribute names. Replace 'colour' with 'color', expand
  overly cryptic names, delete unneeded underscores. Replace "import
  *" with specific imports. Patches by Cheryl Sabella.

* bpo-6739: IDLE: Verify user-entered key sequences by trying to
  bind them with tk. Add tests for all 3 validation functions.
  Original patch by G Polo.  Tests added by Cheryl Sabella.

* bpo-15786: Fix several problems with IDLE's autocompletion box.
  The following should now work: clicking on selection box items;
  using the scrollbar; selecting an item by hitting Return. Hangs on
  MacOSX should no longer happen. Patch by Louie Lu.

* bpo-25514: Add doc subsubsection about IDLE failure to start.
  Popup no-connection message directs users to this section.

* bpo-30642: Fix reference leaks in IDLE tests. Patches by Louie Lu
  and Terry Jan Reedy.

* bpo-30495: Add docstrings for textview.py and use PEP8 names.
  Patches by Cheryl Sabella and Terry Jan Reedy.

* bpo-30290: Help-about: use pep8 names and add tests. Increase
  coverage to 100%. Patches by Louie Lu, Cheryl Sabella, and Terry Jan
  Reedy.

* bpo-30303: Add _utest option to textview; add new tests. Increase
  coverage to 100%. Patches by Louie Lu and Terry Jan Reedy.

* bpo-29071: IDLE colors f-string prefixes (but not invalid ur
  prefixes).

* bpo-28572: Add 10% to coverage of IDLE's test_configdialog. Update
  and augment description of the configuration system.


工具/示例
---------

* bpo-30983: gdb integration commands (py-bt, etc.) work on
  optimized shared builds now, too.  **PEP 523** introduced
  _PyEval_EvalFrameDefault which inlines PyEval_EvalFrameEx on non-
  debug shared builds.  This broke the ability to use py-bt, py-up,
  and a few other Python-specific gdb integrations. The problem is
  fixed by only looking for _PyEval_EvalFrameDefault frames in python-
  gdb.py.  Original patch by Bruno "Polaco" Penteado.

* bpo-29748: Added the slice index converter in Argument Clinic.

* bpo-24037: Argument Clinic now uses the converter
  "bool(accept={int})" rather than "int" for semantical booleans. This
  avoids repeating the default value for Python and C and will help in
  converting to "bool" in future.

* bpo-29367: python-gdb.py now supports also "method-wrapper"
  ("wrapperobject") objects.

* bpo-28023: Fix python-gdb.py didn't support new dict
  implementation.

* bpo-15369: The pybench and pystone microbenchmark have been
  removed from Tools. Please use the new Python benchmark suite
  https://github.com/python/performance which is more reliable and
  includes a portable version of pybench working on Python 2 and
  Python 3.

* bpo-28102: The zipfile module CLI now prints usage to stderr.
  Patch by Stephen J. Turnbull.


C API
-----

* bpo-31338: Added the "Py_UNREACHABLE()" macro for code paths which
  are never expected to be reached.  This and a few other useful
  macros are now documented in the C API manual.

* bpo-30832: Remove own implementation for thread-local storage.
  CPython has provided the own implementation for thread-local storage
  (TLS) on Python/thread.c, it's used in the case which a platform has
  not supplied native TLS.  However, currently all supported platforms
  (Windows and pthreads) have provided native TLS and defined the
  Py_HAVE_NATIVE_TLS macro with unconditional in any case.

* bpo-30708: PyUnicode_AsWideCharString() now raises a ValueError if
  the second argument is NULL and the wchar_t* string contains null
  characters.

* bpo-16500: Deprecate PyOS_AfterFork() and add PyOS_BeforeFork(),
  PyOS_AfterFork_Parent() and PyOS_AfterFork_Child().

* bpo-6532: The type of results of PyThread_start_new_thread() and
  PyThread_get_thread_ident(), and the id parameter of
  PyThreadState_SetAsyncExc() changed from "long" to "unsigned long".

* bpo-27867: Function PySlice_GetIndicesEx() is deprecated and
  replaced with a macro if Py_LIMITED_API is not set or set to the
  value between 0x03050400 and 0x03060000 (not including) or
  0x03060100 or higher.  Added functions PySlice_Unpack() and
  PySlice_AdjustIndices().

* bpo-29083: Fixed the declaration of some public API functions.
  PyArg_VaParse() and PyArg_VaParseTupleAndKeywords() were not
  available in limited API. PyArg_ValidateKeywordArguments(),
  PyArg_UnpackTuple() and Py_BuildValue() were not available in
  limited API of version < 3.3 when PY_SSIZE_T_CLEAN is defined.

* bpo-28769: The result of PyUnicode_AsUTF8AndSize() and
  PyUnicode_AsUTF8() is now of type "const char *" rather of "char *".

* bpo-29058: All stable API extensions added after Python 3.2 are
  now available only when Py_LIMITED_API is set to the PY_VERSION_HEX
  value of the minimum Python version supporting this API.

* bpo-28822: The index parameters *start* and *end* of
  PyUnicode_FindChar() are now adjusted to behave like
  "str[start:end]".

* bpo-28808: PyUnicode_CompareWithASCIIString() now never raises
  exceptions.

* bpo-28761: The fields name and doc of structures PyMemberDef,
  PyGetSetDef, PyStructSequence_Field, PyStructSequence_Desc, and
  wrapperbase are now of type "const char *" rather of "char *".

* bpo-28748: Private variable _Py_PackageContext is now of type
  "const char *" rather of "char *".

* bpo-19569: Compiler warnings are now emitted if use most of
  deprecated functions.

* bpo-28426: Deprecated undocumented functions
  PyUnicode_AsEncodedObject(), PyUnicode_AsDecodedObject(),
  PyUnicode_AsDecodedUnicode() and PyUnicode_AsEncodedUnicode().


Python 3.6.6 final
==================

*发布日期: 2018-06-27*

There were no new changes in version 3.6.6.


Python 3.6.6 RC 1
=================

*发布日期: 2018-06-11*


核心与内置
----------

* bpo-33786: Fix asynchronous generators to handle GeneratorExit in
  athrow() correctly

* bpo-30654: Fixed reset of the SIGINT handler to SIG_DFL on
  interpreter shutdown even when there was a custom handler set
  previously. Patch by Philipp Kerling.

* bpo-33622: Fixed a leak when the garbage collector fails to add an
  object with the "__del__" method or referenced by it into the
  "gc.garbage" list. "PyGC_Collect()" can now be called when an
  exception is set and preserves it.

* bpo-31849: Fix signed/unsigned comparison warning in pyhash.c.

* bpo-33391: Fix a leak in set_symmetric_difference().

* bpo-28055: Fix unaligned accesses in siphash24(). Patch by Rolf
  Eike Beer.

* bpo-33231: 修复 "normalizestring()" 中潜在的内存泄漏。

* bpo-29922: Improved error messages in 'async with' when
  "__aenter__()" or "__aexit__()" return non-awaitable object.

* bpo-33199: Fix "ma_version_tag" in dict implementation is
  uninitialized when copying from key-sharing dict.

* bpo-33041: Fixed jumping when the function contains an "async for"
  loop.

* bpo-32282: Fix an unnecessary ifdef in the include of
  VersionHelpers.h in socketmodule on Windows.

* bpo-21983: Fix a crash in "ctypes.cast()" in case the type
  argument is a ctypes structured data type. Patch by Eryk Sun and
  Oren Milman.


库
--

* bpo-30167: Prevent site.main() exception if PYTHONSTARTUP is set.
  Patch by Steve Weber.

* bpo-33812: Datetime instance d with non-None tzinfo, but with
  d.tzinfo.utcoffset(d) returning None is now treated as naive by the
  astimezone() method.

* bpo-30805: Avoid race condition with debug logging

* bpo-33767: The concatenation ("+") and repetition ("*") sequence
  operations now raise "TypeError" instead of "SystemError" when
  performed on "mmap.mmap" objects.  Patch by Zackery Spytz.

* bpo-32684: Fix gather to propagate cancellation of itself even
  with return_exceptions.

* bpo-33674: Fix a race condition in SSLProtocol.connection_made()
  of asyncio.sslproto: start immediately the handshake instead of
  using call_soon(). Previously, data_received() could be called
  before the handshake started, causing the handshake to hang or fail.

* bpo-31647: Fixed bug where calling write_eof() on a
  _SelectorSocketTransport after it's already closed raises
  AttributeError.

* bpo-33672: Fix Task.__repr__ crash with Cython's bogus coroutines

* bpo-33469: Fix RuntimeError after closing loop that used
  run_in_executor

* bpo-11874: Use a better regex when breaking usage into wrappable
  parts. Avoids bogus assertion errors from custom metavar strings.

* bpo-30877: Fixed a bug in the Python implementation of the JSON
  decoder that prevented the cache of parsed strings from clearing
  after finishing the decoding. Based on patch by c-fos.

* bpo-33548: tempfile._candidate_tempdir_list should consider common
  TEMP locations

* bpo-33542: Prevent "uuid.get_node" from using a DUID instead of a
  MAC on Windows. Patch by Zvi Effron

* bpo-26819: Fix race condition with "ReadTransport.resume_reading"
  in Windows proactor event loop.

* bpo-28556: Minor fixes in typing module: add annotations to
  "NamedTuple.__new__", pass "*args" and "**kwds" in
  "Generic.__new__".  Original PRs by Paulius Šarka and Chad Dombrova.

* bpo-20087: Updated alias mapping with glibc 2.27 supported
  locales.

* bpo-33422: Fix trailing quotation marks getting deleted when
  looking up byte/string literals on pydoc. Patch by Andrés Delfino.

* bpo-33197: Update error message when constructing invalid
  inspect.Parameters Patch by Dong-hee Na.

* bpo-33383: Fixed crash in the get() method of the "dbm.ndbm"
  database object when it is called with a single argument.

* bpo-33329: Fix multiprocessing regression on newer glibcs

* bpo-991266: Fix quoting of the "Comment" attribute of
  "http.cookies.SimpleCookie".

* bpo-33131: Upgrade bundled version of pip to 10.0.1.

* bpo-33308: Fixed a crash in the "parser" module when converting an
  ST object to a tree of tuples or lists with "line_info=False" and
  "col_info=True".

* bpo-33263: Fix FD leak in "_SelectorSocketTransport"  Patch by
  Vlad Starostin.

* bpo-33256: Fix display of "<module>" call in the html produced by
  "cgitb.html()". Patch by Stéphane Blondon.

* bpo-33203: "random.Random.choice()" now raises "IndexError" for
  empty sequences consistently even when called from subclasses
  without a "getrandbits()" implementation.

* bpo-33224: Update difflib.mdiff() for **PEP 479**.  Convert an
  uncaught StopIteration in a generator into a return-statement.

* bpo-33209: End framing at the end of C implementation of
  "pickle.Pickler.dump()".

* bpo-32861: The urllib.robotparser's "__str__" representation now
  includes wildcard entries and the "Crawl-delay" and "Request-rate"
  fields. Patch by Michael Lazar.

* bpo-33096: Allow ttk.Treeview.insert to insert iid that has a
  false boolean value. Note iid=0 and iid=False would be same. Patch
  by Garvit Khatri.

* bpo-33127: ssl模块现在使用LibreSSL 2.7.1编译。

* bpo-33021: Release the GIL during fstat() calls, avoiding hang of
  all threads when calling mmap.mmap(), os.urandom(), and
  random.seed().  Patch by Nir Soffer.

* bpo-27683: Fix a regression in "ipaddress" that result of
  "hosts()" is empty when the network is constructed by a tuple
  containing an integer mask and only 1 bit left for addresses.

* bpo-32844: Fix wrong redirection of a low descriptor (0 or 1) to
  stderr in subprocess if another low descriptor is closed.

* bpo-31908: Fix output of cover files for "trace" module command-
  line tool. Previously emitted cover files only when "--missing"
  option was used. Patch by Michael Selik.

* bpo-31457: If nested log adapters are used, the inner "process()"
  methods are no longer omitted.

* bpo-16865: Support arrays >=2GiB in "ctypes".  Patch by Segev
  Finer.

* bpo-31238: pydoc: the stop() method of the private ServerThread
  class now waits until DocServer.serve_until_quit() completes and
  then explicitly sets its docserver attribute to None to break a
  reference cycle.


文档
----

* bpo-33503: 修复错误的pypi链接

* bpo-33421: 为``typing.AsyncContextManager``添加缺失的文档。

* bpo-33378: Add Korean language switcher for
  https://docs.python.org/3/

* bpo-33276: Clarify that the "__path__" attribute on modules cannot
  be just any value.

* bpo-33201: Modernize documentation for writing C extension types.

* bpo-33195: Deprecate "Py_UNICODE" usage in "c-api/arg" document.
  "Py_UNICODE" related APIs are deprecated since Python 3.3, but it is
  missed in the document.

* bpo-33126: Document PyBuffer_ToContiguous().

* bpo-27212: Modify documentation for the "islice()" recipe to
  consume initial values up to the start index.

* bpo-28247: Update "zipapp" documentation to describe how to make
  standalone applications.

* bpo-18802: Documentation changes for ipaddress.  Patch by Jon
  Foster and Berker Peksag.

* bpo-27428: Update documentation to clarify that
  "WindowsRegistryFinder" implements "MetaPathFinder". (Patch by
  Himanshu Lakhara)

* bpo-8243: Add a note about curses.addch and curses.addstr
  exception behavior when writing outside a window, or pad.

* bpo-31432: Clarify meaning of CERT_NONE, CERT_OPTIONAL, and
  CERT_REQUIRED flags for ssl.SSLContext.verify_mode.


测试
----

* bpo-33655: 忽略运行在BSD平台的ZFS上时test_posix_fallocate的失败。

* bpo-19417: Add test_bdb.py.


构建
----

* bpo-5755: Move "-Wstrict-prototypes" option to "CFLAGS_NODIST"
  from "OPT". This option emitted annoying warnings when building
  extension modules written in C++.

* bpo-33614: Ensures module definition files for the stable ABI on
  Windows are correctly regenerated.

* bpo-33522: Enable CI builds on Visual Studio Team Services at
  https://python.visualstudio.com/cpython

* bpo-33012: Add "-Wno-cast-function-type" for gcc 8 for silencing
  warnings about function casts like casting to PyCFunction in method
  definition lists.

* bpo-33394: Enable the verbose build for extension modules, when
  GNU make is passed macros on the command line.


Windows
-------

* bpo-33184: Update Windows installer to OpenSSL 1.0.2o.


macOS
-----

* bpo-33184: Update macOS installer build to use OpenSSL 1.0.2o.


IDLE
----

* bpo-33656: On Windows, add API call saying that tk scales for DPI.
  On Windows 8.1+ or 10, with DPI compatibility properties of the
  Python binary unchanged, and a monitor resolution greater than 96
  DPI, this should make text and lines sharper.  It should otherwise
  have no effect.

* bpo-33768: Clicking on a context line moves that line to the top
  of the editor window.

* bpo-33763: IDLE: Use read-only text widget for code context
  instead of label widget.

* bpo-33664: Scroll IDLE editor text by lines. Previously, the mouse
  wheel and scrollbar slider moved text by a fixed number of pixels,
  resulting in partial lines at the top of the editor box.  The change
  also applies to the shell and grep output windows, but not to read-
  only text views.

* bpo-33679: Enable theme-specific color configuration for Code
  Context. Use the Highlights tab to see the setting for built-in
  themes or add settings to custom themes.

* bpo-33642: Display up to maxlines non-blank lines for Code
  Context. If there is no current context, show a single blank line.

* bpo-33628: IDLE: Cleanup codecontext.py and its test.

* bpo-33564: IDLE's code context now recognizes async as a block
  opener.

* bpo-29706: IDLE now colors async and await as keywords in 3.6.
  They become full keywords in 3.7.

* bpo-21474: Update word/identifier definition from ascii to
  unicode. In text and entry boxes, this affects selection by double-
  click, movement left/right by control-left/right, and deletion
  left/right by control-BACKSPACE/DEL.

* bpo-33204: IDLE: consistently color invalid string prefixes. A 'u'
  string prefix cannot be paired with either 'r' or 'f'. Consistently
  color as much of the prefix, starting at the right, as is valid.
  Revise and extend colorizer test.

* bpo-32831: Add docstrings and tests for codecontext.


工具/示例
---------

* bpo-33189: **pygettext.py** now recognizes only literal strings as
  docstrings and translatable strings, and rejects bytes literals and
  f-string expressions.

* bpo-31920: Fixed handling directories as arguments in the
  "pygettext" script. Based on patch by Oleg Krasnikov.

* bpo-29673: Fix pystackv and pystack gdbinit macros.

* bpo-32885: Add an "-n" flag for "Tools/scripts/pathfix.py" to
  disable automatic backup creation (files with "~" suffix).

* bpo-31583: Fix 2to3 for using with --add-suffix option but without
  --output-dir option for relative path to files in current directory.


C API
-----

* bpo-32374: Document that m_traverse for multi-phase initialized
  modules can be called with m_state=NULL, and add a sanity check


Python 3.6.5 final
==================

*Release date: 2018-03-28*


测试
----

* bpo-32872: Avoid regrtest compatibility issue with namespace
  packages.


构建
----

* bpo-33163: Upgrade pip to 9.0.3 and setuptools to v39.0.1.


Python 3.6.5 release candidate 1
================================

*Release date: 2018-03-13*


安全
----

* bpo-33001: Minimal fix to prevent buffer overrun in os.symlink on
  Windows

* bpo-32981: Regexes in difflib and poplib were vulnerable to
  catastrophic backtracking. These regexes formed potential DOS
  vectors (REDOS). They have been refactored. This resolves
  CVE-2018-1060 and CVE-2018-1061. Patch by Jamie Davis.


核心与内置
----------

* bpo-33026: Fixed jumping out of "with" block by setting f_lineno.

* bpo-17288: Prevent jumps from 'return' and 'exception' trace
  events.

* bpo-32889: Update Valgrind suppression list to account for the
  rename of "Py_ADDRESS_IN_RANG" to "address_in_range".

* bpo-32650: Pdb and other debuggers dependent on bdb.py will
  correctly step over (next command) native coroutines. Patch by Pablo
  Galindo.

* bpo-32685: Improve suggestion when the Python 2 form of print
  statement is either present on the same line as the header of a
  compound statement or else terminated by a semi-colon instead of a
  newline. Patch by Nitish Chandra.

* bpo-32583: Fix possible crashing in builtin Unicode decoders
  caused by write out-of-bound errors when using customized decode
  error handlers.

* bpo-26163: Improved frozenset() hash to create more distinct hash
  values when faced with datasets containing many similar values.

* bpo-27169: The "__debug__" constant is now optimized out at
  compile time. This fixes also bpo-22091.

* bpo-32329: "sys.flags.hash_randomization" is now properly set to 0
  when hash randomization is turned off by "PYTHONHASHSEED=0".

* bpo-30416: The optimizer is now protected from spending much time
  doing complex calculations and consuming much memory for creating
  large constants in constant folding.

* bpo-18533: "repr()" on a dict containing its own "values()" or
  "items()" no longer raises "RecursionError"; OrderedDict similarly.
  Instead, use "...", as for other recursive structures.  Patch by Ben
  North.

* bpo-32028: Leading whitespace is now correctly ignored when
  generating suggestions for converting Py2 print statements to Py3
  builtin print function calls. Patch by Sanyam Khurana.

* bpo-32137: The repr of deeply nested dict now raises a
  RecursionError instead of crashing due to a stack overflow.


库
--

* bpo-33064: lib2to3 now properly supports trailing commas after
  "*args" and "**kwargs" in function signatures.

* bpo-31804: Avoid failing in multiprocessing.Process if the
  standard streams are closed or None at exit.

* bpo-33037: Skip sending/receiving data after SSL transport
  closing.

* bpo-30353: Fix ctypes pass-by-value for structs on 64-bit
  Cygwin/MinGW.

* bpo-33009: Fix inspect.signature() for single-parameter
  partialmethods.

* bpo-32969: Expose several missing constants in zlib and fix
  corresponding documentation.

* bpo-32713: Fixed tarfile.itn handling of out-of-bounds float
  values. Patch by Joffrey Fuhrer.

* bpo-30622: The ssl module now detects missing NPN support in
  LibreSSL.

* bpo-32922: dbm.open() now encodes filename with the filesystem
  encoding rather than default encoding.

* bpo-32859: In "os.dup2", don't check every call whether the "dup3"
  syscall exists or not.

* bpo-21060: Rewrite confusing message from setup.py upload from "No
  dist file created in earlier command" to the more helpful "Must
  create and upload files in one command".

* bpo-32857: In "tkinter", "after_cancel(None)" now raises a
  "ValueError" instead of canceling the first scheduled function.
  Patch by Cheryl Sabella.

* bpo-32852: Make sure sys.argv remains as a list when running
  trace.

* bpo-32841: Fixed "asyncio.Condition" issue which silently ignored
  cancellation after notifying and cancelling a conditional lock.
  Patch by Bar Harel.

* bpo-31787: Fixed refleaks of "__init__()" methods in various
  modules. (Contributed by Oren Milman)

* bpo-30157: Fixed guessing quote and delimiter in
  csv.Sniffer.sniff() when only the last field is quoted.  Patch by
  Jake Davis.

* bpo-32394: socket: Remove TCP_FASTOPEN, TCP_KEEPCNT flags on older
  version Windows during run-time.

* bpo-32777: Fix a rare but potential pre-exec child process
  deadlock in subprocess on POSIX systems when marking file
  descriptors inheritable on exec in the child process.  This bug
  appears to have been introduced in 3.4.

* bpo-32647: The ctypes module used to depend on indirect linking
  for dlopen. The shared extension is now explicitly linked against
  libdl on platforms with dl.

* bpo-32734: Fixed "asyncio.Lock()" safety issue which allowed
  acquiring and locking the same lock multiple times, without it being
  free. Patch by Bar Harel.

* bpo-32727: Do not include name field in SMTP envelope from
  address. Patch by Stéphane Wirtel

* bpo-27931: Fix email address header parsing error when the
  username is an empty quoted string. Patch by Xiang Zhang.

* bpo-32304: distutils' upload command no longer corrupts tar files
  ending with a CR byte, and no longer tries to convert CR to CRLF in
  any of the upload text fields.

* bpo-32502: uuid.uuid1 no longer raises an exception if a 64-bit
  hardware address is encountered.

* bpo-31848: Fix the error handling in Aifc_read.initfp() when the
  SSND chunk is not found. Patch by Zackery Spytz.

* bpo-32555: On FreeBSD and Solaris, os.strerror() now always decode
  the byte string from the current locale encoding, rather than using
  ASCII/surrogateescape in some cases.

* bpo-32521: The nis module is now compatible with new libnsl and
  headers location.

* bpo-32473: Improve ABCMeta._dump_registry() output readability

* bpo-32521: glibc has removed Sun RPC. Use replacement libtirpc
  headers and library in nis module.

* bpo-32228: Ensure that "truncate()" preserves the file position
  (as reported by "tell()") after writes longer than the buffer size.

* bpo-26133: Don't unsubscribe signals in asyncio UNIX event loop on
  interpreter shutdown.

* bpo-32185: The SSL module no longer sends IP addresses in SNI TLS
  extension on platforms with OpenSSL 1.0.2+ or inet_pton.

* bpo-32323: "urllib.parse.urlsplit()" does not convert zone-id
  (scope) to lower case for scoped IPv6 addresses in hostnames now.

* bpo-32302: Fix bdist_wininst of distutils for CRT v142: it binary
  compatible with CRT v140.

* bpo-32255: A single empty field is now always quoted when written
  into a CSV file. This allows to distinguish an empty row from a row
  consisting of a single empty field. Patch by Licht Takeuchi.

* bpo-32277: Raise "NotImplementedError" instead of "SystemError" on
  platforms where "chmod(..., follow_symlinks=False)" is not
  supported. Patch by Anthony Sottile.

* bpo-32199: The getnode() ip getter now uses 'ip link' instead of
  'ip link list'.

* bpo-27456: Ensure TCP_NODELAY is set on Linux. Tests by Victor
  Stinner.

* bpo-31900: The "locale.localeconv()" function now sets temporarily
  the "LC_CTYPE" locale to the "LC_NUMERIC" locale to decode
  "decimal_point" and "thousands_sep" byte strings if they are non-
  ASCII or longer than 1 byte, and the "LC_NUMERIC" locale is
  different than the "LC_CTYPE" locale. This temporary change affects
  other threads. Same change for the "str.format()" method when
  formatting a number ("int", "float", "float" and subclasses) with
  the "n" type (ex: "'{:n}'.format(1234)").

* bpo-31802: Importing native path module ("posixpath", "ntpath")
  now works even if the "os" module still is not imported.


文档
----

* bpo-17232: Clarify docs for -O and -OO.  Patch by Terry Reedy.

* bpo-32800: Update link to w3c doc for xml default namespaces.

* bpo-8722: Document "__getattr__()" behavior when property "get()"
  method raises "AttributeError".

* bpo-32614: Modify RE examples in documentation to use raw strings
  to prevent "DeprecationWarning" and add text to REGEX HOWTO to
  highlight the deprecation.

* bpo-31972: Improve docstrings for "pathlib.PurePath" subclasses.

* bpo-17799: Explain real behaviour of sys.settrace and
  sys.setprofile and their C-API counterparts regarding which type of
  events are received in each function. Patch by Pablo Galindo
  Salgado.


测试
----

* bpo-32517: Fix failing "test_asyncio" on macOS 10.12.2+ due to
  transport of "KqueueSelector" loop was not being closed.

* bpo-32721: Fix test_hashlib to not fail if the _md5 module is not
  built.

* bpo-32252: Fix faulthandler_suppress_crash_report() used to
  prevent core dump files when testing crashes. getrlimit() returns
  zero on success.

* bpo-31518: Debian Unstable has disabled TLS 1.0 and 1.1 for
  SSLv23_METHOD(). Change TLS/SSL protocol of some tests to
  PROTOCOL_TLS or PROTOCOL_TLSv1_2 to make them pass on Debian.


构建
----

* bpo-32635: Fix segfault of the crypt module when libxcrypt is
  provided instead of libcrypt at the system.


Windows
-------

* bpo-33016: Fix potential use of uninitialized memory in
  nt._getfinalpathname

* bpo-32903: Fix a memory leak in os.chdir() on Windows if the
  current directory is set to a UNC path.

* bpo-31966: Fixed WindowsConsoleIO.write() for writing empty data.

* bpo-32409: Ensures activate.bat can handle Unicode contents.

* bpo-32457: Improves handling of denormalized executable path when
  launching Python.

* bpo-32370: Use the correct encoding for ipconfig output in the
  uuid module. Patch by Segev Finer.

* bpo-29248: Fix "os.readlink()" on Windows, which was mistakenly
  treating the "PrintNameOffset" field of the reparse data buffer as a
  number of characters instead of bytes. Patch by Craig Holmquist and
  SSE4.

* bpo-32588: Create standalone _distutils_findvs module.


macOS
-----

* bpo-32726: Provide an additional, more modern macOS installer
  variant that supports macOS 10.9+ systems in 64-bit mode only.
  Upgrade the supplied third-party libraries to OpenSSL 1.0.2n, XZ
  5.2.3, and SQLite 3.22.0. The 10.9+ installer now links with and
  supplies its own copy of Tcl/Tk 8.6.8.


IDLE
----

* bpo-32984: Set "__file__" while running a startup file.  Like
  Python, IDLE optionally runs one startup file in the Shell window
  before presenting the first interactive input prompt.  For IDLE,
  "-s" runs a file named in environmental variable  "IDLESTARTUP" or
  "PYTHONSTARTUP"; "-r file" runs "file".  Python sets "__file__" to
  the startup file name before running the file and unsets it before
  the first prompt.  IDLE now does the same when run normally, without
  the "-n" option.

* bpo-32940: Simplify and rename StringTranslatePseudoMapping in
  pyparse.

* bpo-32916: Change "str" to "code" in pyparse.

* bpo-32905: Remove unused code in pyparse module.

* bpo-32874: Add tests for pyparse.

* bpo-32837: Using the system and place-dependent default encoding
  for open() is a bad idea for IDLE's system and location-independent
  files.

* bpo-32826: Add "encoding=utf-8" to open() in IDLE's
  test_help_about. GUI test test_file_buttons() only looks at initial
  ascii-only lines, but failed on systems where open() defaults to
  'ascii' because readline() internally reads and decodes far enough
  ahead to encounter a non-ascii character in CREDITS.txt.

* bpo-32765: Update configdialog General tab docstring to add new
  widgets to the widget list.


工具/示例
---------

* bpo-24960: 2to3 and lib2to3 can now read pickled grammar files
  using pkgutil.get_data() rather than probing the filesystem. This
  lets 2to3 and lib2to3 work when run from a zipfile.

* bpo-32222: Fix pygettext not extracting docstrings for functions
  with type annotated arguments. Patch by Toby Harradine.


C API
-----

* bpo-29084: Undocumented C API for OrderedDict has been excluded
  from the limited C API. It was added by mistake and actually never
  worked in the limited C API.


Python 3.6.4 final
==================

*Release date: 2017-12-18*

There were no new code changes in version 3.6.4 since v3.6.4rc1.


Python 3.6.4 release candidate 1
================================

*Release date: 2017-12-05*


核心与内置
----------

* bpo-32176: co_flags.CO_NOFREE is now always set correctly by the
  code object constructor based on freevars and cellvars, rather than
  needing to be set correctly by the caller. This ensures it will be
  cleared automatically when additional cell references are injected
  into a modified code object and function.

* bpo-31949: Fixed several issues in printing tracebacks
  (PyTraceBack_Print()). Setting sys.tracebacklimit to 0 or less now
  suppresses printing tracebacks. Setting sys.tracebacklimit to None
  now causes using the default limit. Setting sys.tracebacklimit to an
  integer larger than LONG_MAX now means using the limit LONG_MAX
  rather than the default limit. Fixed integer overflows in the case
  of more than 2**31 traceback items on Windows. Fixed output errors
  handling.

* bpo-30696: Fix the interactive interpreter looping endlessly when
  no memory.

* bpo-20047: Bytearray methods partition() and rpartition() now
  accept only bytes-like objects as separator, as documented.  In
  particular they now raise TypeError rather of returning a bogus
  result when an integer is passed as a separator.

* bpo-31852: Fix a segmentation fault caused by a combination of the
  async soft keyword and continuation lines.

* bpo-21720: BytesWarning no longer emitted when the *fromlist*
  argument of "__import__()" or the "__all__" attribute of the module
  contain bytes instances.

* bpo-31825: Fixed OverflowError in the 'unicode-escape' codec and
  in codecs.escape_decode() when decode an escaped non-ascii byte.

* bpo-28603: Print the full context/cause chain of exceptions on
  interpreter exit, even if an exception in the chain is unhashable or
  compares equal to later ones. Patch by Zane Bitter.

* bpo-31786: Fix timeout rounding in the select module to round
  correctly negative timeouts between -1.0 and 0.0. The functions now
  block waiting for events as expected. Previously, the call was
  incorrectly non-blocking. Patch by Pablo Galindo.

* bpo-31642: Restored blocking "from package import module" by
  setting sys.modules["package.module"] to None.

* bpo-31626: Fixed a bug in debug memory allocator.  There was a
  write to freed memory after shrinking a memory block.

* bpo-31619: Fixed a ValueError when convert a string with large
  number of underscores to integer with binary base.

* bpo-31592: Fixed an assertion failure in Python parser in case of
  a bad "unicodedata.normalize()". Patch by Oren Milman.

* bpo-31588: Raise a "TypeError" with a helpful error message when
  class creation fails due to a metaclass with a bad "__prepare__()"
  method. Patch by Oren Milman.

* bpo-31566: Fix an assertion failure in "_warnings.warn()" in case
  of a bad "__name__" global. Patch by Oren Milman.

* bpo-31505: Fix an assertion failure in "json", in case
  "_json.make_encoder()" received a bad "encoder()" argument. Patch by
  Oren Milman.

* bpo-31492: Fix assertion failures in case of failing to import
  from a module with a bad "__name__" attribute, and in case of
  failing to access an attribute of such a module. Patch by Oren
  Milman.

* bpo-31490: Fix an assertion failure in "ctypes" class definition,
  in case the class has an attribute whose name is specified in
  "_anonymous_" but not in "_fields_". Patch by Oren Milman.

* bpo-31478: Fix an assertion failure in "_random.Random.seed()" in
  case the argument has a bad "__abs__()" method. Patch by Oren
  Milman.

* bpo-31315: Fix an assertion failure in imp.create_dynamic(), when
  spec.name is not a string. Patch by Oren Milman.

* bpo-31311: Fix a crash in the "__setstate__()" method of
  "ctypes._CData", in case of a bad "__dict__". Patch by Oren Milman.

* bpo-31293: Fix crashes in true division and multiplication of a
  timedelta object by a float with a bad as_integer_ratio() method.
  Patch by Oren Milman.

* bpo-31285: Fix an assertion failure in "warnings.warn_explicit",
  when the return value of the received loader's get_source() has a
  bad splitlines() method. Patch by Oren Milman.

* bpo-30817: "PyErr_PrintEx()" clears now the ignored exception that
  may be raised by "_PySys_SetObjectId()", for example when no memory.


库
--

* bpo-28556: Two minor fixes for "typing" module: allow shallow
  copying instances of generic classes, improve interaction of
  "__init_subclass__" with generics. Original PRs by Ivan Levkivskyi.

* bpo-27240: The header folding algorithm for the new email policies
  has been rewritten, which also fixes bpo-30788, bpo-31831, and
  bpo-32182.  In particular, RFC2231 folding is now done correctly.

* bpo-32186: io.FileIO.readall() and io.FileIO.read() now release
  the GIL when getting the file size. Fixed hang of all threads with
  inaccessible NFS server. Patch by Nir Soffer.

* bpo-12239: Make "msilib.SummaryInformation.GetProperty()" return
  "None" when the value of property is "VT_EMPTY".  Initial patch by
  Mark Mc Mahon.

* bpo-31325: Fix wrong usage of "collections.namedtuple()" in the
  "RobotFileParser.parse()" method. Initial patch by Robin Wellner.

* bpo-12382: "msilib.OpenDatabase()" now raises a better exception
  message when it couldn't open or create an MSI file.  Initial patch
  by William Tisäter.

* bpo-32110: "codecs.StreamReader.read(n)" now returns not more than
  *n* characters/bytes for non-negative *n*. This makes it compatible
  with "read()" methods of other file-like objects.

* bpo-32072: Fixed issues with binary plists: Fixed saving
  bytearrays. Identical objects will be saved only once. Equal
  references will be load as identical objects. Added support for
  saving and loading recursive data structures.

* bpo-32034: Make asyncio.IncompleteReadError and LimitOverrunError
  pickleable.

* bpo-32015: Fixed the looping of asyncio in the case of
  reconnection the socket during waiting async read/write from/to the
  socket.

* bpo-32011: Restored support of loading marshal files with the
  TYPE_INT64 code. These files can be produced in Python 2.7.

* bpo-31970: Reduce performance overhead of asyncio debug mode.

* bpo-9678: Fixed determining the MAC address in the uuid module:
  Using ifconfig on NetBSD and OpenBSD. Using arp on Linux, FreeBSD,
  NetBSD and OpenBSD. Based on patch by Takayuki Shimizukawa.

* bpo-30057: Fix potential missed signal in signal.signal().

* bpo-31933: Fix Blake2 params leaf_size and node_offset on big
  endian platforms. Patch by Jack O'Connor.

* bpo-31927: Fixed compilation of the socket module on NetBSD 8.
  Fixed assertion failure or reading arbitrary data when parse a
  AF_BLUETOOTH address on NetBSD and DragonFly BSD.

* bpo-27666: Fixed stack corruption in curses.box() and
  curses.ungetmouse() when the size of types chtype or mmask_t is less
  than the size of C long. curses.box() now accepts characters as
  arguments.  Based on patch by Steve Fink.

* bpo-31897: plistlib now catches more errors when read binary
  plists and raises InvalidFileException instead of unexpected
  exceptions.

* bpo-25720: Fix the method for checking pad state of curses WINDOW.
  Patch by Masayuki Yamamoto.

* bpo-31893: Fixed the layout of the kqueue_event structure on
  OpenBSD and NetBSD. Fixed the comparison of the kqueue_event
  objects.

* bpo-31891: Fixed building the curses module on NetBSD.

* bpo-28416: Instances of pickle.Pickler subclass with the
  persistent_id() method and pickle.Unpickler subclass with the
  persistent_load() method no longer create reference cycles.

* bpo-28326: Fix multiprocessing.Process when stdout and/or stderr
  is closed or None.

* bpo-31457: If nested log adapters are used, the inner "process()"
  methods are no longer omitted.

* bpo-31457: The "manager" property on LoggerAdapter objects is now
  properly settable.

* bpo-31806: Fix timeout rounding in time.sleep(),
  threading.Lock.acquire() and socket.socket.settimeout() to round
  correctly negative timeouts between -1.0 and 0.0. The functions now
  block waiting for events as expected. Previously, the call was
  incorrectly non-blocking. Patch by Pablo Galindo.

* bpo-28603: traceback: Fix a TypeError that occurred during
  printing of exception tracebacks when either the current exception
  or an exception in its context/cause chain is unhashable. Patch by
  Zane Bitter.

* bpo-30058: Fixed buffer overflow in select.kqueue.control().

* bpo-31770: Prevent a crash when calling the "__init__()" method of
  a "sqlite3.Cursor" object more than once. Patch by Oren Milman.

* bpo-31672: "idpattern" in "string.Template" matched some non-ASCII
  characters. Now it uses "-i" regular expression local flag to avoid
  non-ASCII characters.

* bpo-31764: Prevent a crash in "sqlite3.Cursor.close()" in case the
  "Cursor" object is uninitialized. Patch by Oren Milman.

* bpo-31752: Fix possible crash in timedelta constructor called with
  custom integers.

* bpo-31701: On Windows, faulthandler.enable() now ignores MSC and
  COM exceptions.

* bpo-31728: Prevent crashes in "_elementtree" due to unsafe cleanup
  of "Element.text" and "Element.tail". Patch by Oren Milman.

* bpo-31620: an empty asyncio.Queue now doesn't leak memory when
  queue.get pollers timeout

* bpo-31632: Fix method set_protocol() of class
  _SSLProtocolTransport in asyncio module. This method was previously
  modifying a wrong reference to the protocol.

* bpo-31675: Fixed memory leaks in Tkinter's methods splitlist() and
  split() when pass a string larger than 2 GiB.

* bpo-31673: Fixed typo in the name of Tkinter's method
  adderrorinfo().

* bpo-30806: Fix the string representation of a netrc object.

* bpo-15037: Added a workaround for getkey() in curses for ncurses
  5.7 and earlier.

* bpo-25351: Avoid venv activate failures with undefined variables

* bpo-25532: inspect.unwrap() will now only try to unwrap an object
  sys.getrecursionlimit() times, to protect against objects which
  create a new object on every attribute access.

* bpo-30347: Stop crashes when concurrently iterate over
  itertools.groupby() iterators.

* bpo-31516: "threading.current_thread()" should not return a dummy
  thread at shutdown.

* bpo-31351: python -m ensurepip now exits with non-zero exit code
  if pip bootstrapping has failed.

* bpo-31482: "random.seed()" now works with bytes in version=1

* bpo-31334: Fix "poll.poll([timeout])" in the "select" module for
  arbitrary negative timeouts on all OSes where it can only be a non-
  negative integer or -1. Patch by Riccardo Coccioli.

* bpo-31310: multiprocessing's semaphore tracker should be launched
  again if crashed.

* bpo-31308: Make multiprocessing's forkserver process immune to
  Ctrl-C and other user interruptions. If it crashes, restart it when
  necessary.


文档
----

* bpo-32105: Added asyncio.BaseEventLoop.connect_accepted_socket
  versionadded marker.

* bpo-31537: Fix incorrect usage of "get_history_length" in readline
  documentation example code. Patch by Brad Smith.

* bpo-30085: The operator functions without double underscores are
  preferred for clarity. The one with underscores are only kept for
  back-compatibility.


测试
----

* bpo-31380: Skip test_httpservers test_undecodable_file on macOS:
  fails on APFS.

* bpo-31705: Skip test_socket.test_sha256() on Linux kernel older
  than 4.5. The test fails with ENOKEY on kernel 3.10 (on ppc64le). A
  fix was merged into the kernel 4.5.

* bpo-31174: Fix test_tools.test_unparse: DirectoryTestCase now
  stores the names sample to always test the same files. It prevents
  false alarms when hunting reference leaks.

* bpo-30695: Add the "set_nomemory(start, stop)" and
  "remove_mem_hooks()" functions to the _testcapi module.


构建
----

* bpo-32059: "detect_modules()" in "setup.py" now also searches the
  sysroot paths when cross-compiling.

* bpo-31957: Fixes Windows SDK version detection when building for
  Windows.

* bpo-31609: Fixes quotes in PCbuild/clean.bat

* bpo-31934: Abort the build when building out of a not clean source
  tree.

* bpo-31926: Fixed Argument Clinic sometimes causing compilation
  errors when there was more than one function and/or method in a .c
  file with the same name.

* bpo-28791: Update Windows builds to use SQLite 3.21.0.

* bpo-28791: Update OS X installer to use SQLite 3.21.0.

* bpo-22140: Prevent double substitution of prefix in python-
  config.sh.

* bpo-31536: Avoid wholesale rebuild after "make regen-all" if
  nothing changed.


Windows
-------

* bpo-1102: Return "None" when "View.Fetch()" returns
  "ERROR_NO_MORE_ITEMS" instead of raising "MSIError". Initial patch
  by Anthony Tuininga.

* bpo-31944: Fixes Modify button in Apps and Features dialog.


macOS
-----

* bpo-31392: Update macOS installer to use OpenSSL 1.0.2m


IDLE
----

* bpo-32207: Improve tk event exception tracebacks in IDLE. When tk
  event handling is driven by IDLE's run loop, a confusing and
  distracting queue.EMPTY traceback context is no longer added to tk
  event exception tracebacks.  The traceback is now the same as when
  event handling is driven by user code.  Patch based on a suggestion
  by Serhiy Storchaka.

* bpo-32164: Delete unused file idlelib/tabbedpages.py. Use of
  TabbedPageSet in configdialog was replaced by ttk.Notebook.

* bpo-32100: IDLE: Fix old and new bugs in pathbrowser; improve
  tests. Patch mostly by Cheryl Sabella.

* bpo-31858: IDLE -- Restrict shell prompt manipulation to the
  shell. Editor and output windows only see an empty last prompt line.
  This simplifies the code and fixes a minor bug when newline is
  inserted. Sys.ps1, if present, is read on Shell start-up, but is not
  set or changed.

* bpo-31860: The font sample in the IDLE configuration dialog is now
  editable. Changes persist while IDLE remains open

* bpo-31836: Test_code_module now passes if run after test_idle,
  which sets ps1. The code module uses sys.ps1 if present or sets it
  to '>>> ' if not. Test_code_module now properly tests both
  behaviors.  Ditto for ps2.

* bpo-28603: Fix a TypeError that caused a shell restart when
  printing a traceback that includes an exception that is unhashable.
  Patch by Zane Bitter.

* bpo-13802: Use non-Latin characters in the IDLE's Font settings
  sample. Even if one selects a font that defines a limited subset of
  the unicode Basic Multilingual Plane, tcl/tk will use other fonts
  that define a character. The expanded example give users of non-
  Latin characters a better idea of what they might see in IDLE's
  shell and editors. To make room for the expanded sample, frames on
  the Font tab are re-arranged. The Font/Tabs help explains a bit
  about the additions.

* bpo-31460: Simplify the API of IDLE's Module Browser. Passing a
  widget instead of an flist with a root widget opens the option of
  creating a browser frame that is only part of a window.  Passing a
  full file name instead of pieces assumed to come from a .py file
  opens the possibility of browsing python files that do not end in
  .py.

* bpo-31649: IDLE - Make _htest, _utest parameters keyword only.

* bpo-31559: Remove test order dependence in idle_test.test_browser.

* bpo-31459: Rename IDLE's module browser from Class Browser to
  Module Browser. The original module-level class and method browser
  became a module browser, with the addition of module-level
  functions, years ago. Nested classes and functions were added
  yesterday.  For back- compatibility, the virtual event <<open-class-
  browser>>, which appears on the Keys tab of the Settings dialog, is
  not changed. Patch by Cheryl Sabella.

* bpo-31500: Default fonts now are scaled on HiDPI displays.

* bpo-1612262: IDLE module browser now shows nested classes and
  functions. Original patches for code and tests by Guilherme Polo and
  Cheryl Sabella, respectively.


工具/示例
---------

* bpo-30722: Make redemo work with Python 3.6 and newer versions.
  Also, remove the "LOCALE" option since it doesn't work with string
  patterns in Python 3. Patch by Christoph Sarnowski.


C API
-----

* bpo-20891: Fix PyGILState_Ensure(). When PyGILState_Ensure() is
  called in a non-Python thread before PyEval_InitThreads(), only call
  PyEval_InitThreads() after calling PyThreadState_New() to fix a
  crash.

* bpo-31532: Fix memory corruption due to allocator mix in getpath.c
  between Py_GetPath() and Py_SetPath()

* bpo-30697: The "PyExc_RecursionErrorInst" singleton is removed and
  "PyErr_NormalizeException()" does not use it anymore. This singleton
  is persistent and its members being never cleared may cause a
  segfault during finalization of the interpreter. See also bpo-22898.


Python 3.6.3 final
==================

*Release date: 2017-10-03*


库
--

* bpo-31641: Re-allow arbitrary iterables in
  "concurrent.futures.as_completed()". Fixes regression in 3.6.3rc1.


构建
----

* bpo-31662: Fix typos in Windows "uploadrelease.bat" script. Fix
  Windows Doc build issues in "Doc/make.bat".

* bpo-31423: Fix building the PDF documentation with newer versions
  of Sphinx.


Python 3.6.3 release candidate 1
================================

*Release date: 2017-09-18*


安全
----

* bpo-29781: SSLObject.version() now correctly returns None when
  handshake over BIO has not been performed yet.

* bpo-30947: Upgrade libexpat embedded copy from version 2.2.1 to
  2.2.3 to get security fixes.


核心与内置
----------

* bpo-31471: Fix an assertion failure in "subprocess.Popen()" on
  Windows, in case the env argument has a bad keys() method. Patch by
  Oren Milman.

* bpo-31418: Fix an assertion failure in "PyErr_WriteUnraisable()"
  in case of an exception with a bad "__module__" attribute. Patch by
  Oren Milman.

* bpo-31416: Fix assertion failures in case of a bad
  warnings.filters or warnings.defaultaction. Patch by Oren Milman.

* bpo-31411: Raise a TypeError instead of SystemError in case
  warnings.onceregistry is not a dictionary. Patch by Oren Milman.

* bpo-31373: Fix several possible instances of undefined behavior
  due to floating-point demotions.

* bpo-30465: Location information ("lineno" and "col_offset") in
  f-strings is now (mostly) correct.  This fixes tools like flake8
  from showing warnings on the wrong line (typically the first line of
  the file).

* bpo-31343: Include sys/sysmacros.h for major(), minor(), and
  makedev(). GNU C libray plans to remove the functions from
  sys/types.h.

* bpo-31291: Fix an assertion failure in
  "zipimport.zipimporter.get_data" on Windows, when the return value
  of "pathname.replace('/','\\')" isn't a string. Patch by Oren
  Milman.

* bpo-31271: Fix an assertion failure in the write() method of
  "io.TextIOWrapper", when the encoder doesn't return a bytes object.
  Patch by Oren Milman.

* bpo-31243: Fix a crash in some methods of "io.TextIOWrapper", when
  the decoder's state is invalid. Patch by Oren Milman.

* bpo-30721: "print" now shows correct usage hint for using Python 2
  redirection syntax.  Patch by Sanyam Khurana.

* bpo-31070: Fix a race condition in importlib _get_module_lock().

* bpo-31095: Fix potential crash during GC caused by "tp_dealloc"
  which doesn't call "PyObject_GC_UnTrack()".

* bpo-31071: Avoid masking original TypeError in call with *
  unpacking when other arguments are passed.

* bpo-30978: str.format_map() now passes key lookup exceptions
  through. Previously any exception was replaced with a KeyError
  exception.

* bpo-30808: Use _Py_atomic API for concurrency-sensitive signal
  state.

* bpo-30876: Relative import from unloaded package now reimports the
  package instead of failing with SystemError.  Relative import from
  non-package now fails with ImportError rather than SystemError.

* bpo-30703: Improve signal delivery. Avoid using Py_AddPendingCall
  from signal handler, to avoid calling signal-unsafe functions. The
  tests I'm adding here fail without the rest of the patch, on Linux
  and OS X. This means our signal delivery logic had defects (some
  signals could be lost).

* bpo-30765: Avoid blocking in pthread_mutex_lock() when
  PyThread_acquire_lock() is asked not to block.

* bpo-31161: Make sure the 'Missing parentheses' syntax error
  message is only applied to SyntaxError, not to subclasses. Patch by
  Martijn Pieters.

* bpo-30814: Fixed a race condition when import a submodule from a
  package.

* bpo-30597: "print" now shows expected input in custom error
  message when used as a Python 2 statement. Patch by Sanyam Khurana.


库
--

* bpo-31499: xml.etree: Fix a crash when a parser is part of a
  reference cycle.

* bpo-28556: typing.get_type_hints now finds the right globalns for
  classes and modules by default (when no "globalns" was specified by
  the caller).

* bpo-28556: Speed improvements to the "typing" module.  Original
  PRs by Ivan Levkivskyi and Mitar.

* bpo-31544: The C accelerator module of ElementTree ignored
  exceptions raised when looking up TreeBuilder target methods in
  XMLParser().

* bpo-31234: socket.create_connection() now fixes manually a
  reference cycle: clear the variable storing the last exception on
  success.

* bpo-31457: LoggerAdapter objects can now be nested.

* bpo-31400: Improves SSL error handling to avoid losing error
  numbers.

* bpo-28958: ssl.SSLContext() now uses OpenSSL error information
  when a context cannot be instantiated.

* bpo-27340: SSLSocket.sendall() now uses memoryview to create
  slices of data. This fixes support for all bytes-like object. It is
  also more efficient and avoids costly copies.

* bpo-31178: Fix string concatenation bug in rare error path in the
  subprocess module

* bpo-31350: Micro-optimize "asyncio._get_running_loop()" to become
  up to 10% faster.

* bpo-31170: expat: Update libexpat from 2.2.3 to 2.2.4. Fix copying
  of partial characters for UTF-8 input (libexpat bug 115):
  https://github.com/libexpat/libexpat/issues/115

* bpo-29136: Add TLS 1.3 cipher suites and OP_NO_TLSv1_3.

* bpo-29212: Fix concurrent.futures.thread.ThreadPoolExecutor
  threads to have a non repr() based thread name by default when no
  thread_name_prefix is supplied. They will now identify themselves as
  "ThreadPoolExecutor-y_n".

* bpo-9146: Fix a segmentation fault in _hashopenssl when standard
  hash functions such as md5 are not available in the linked OpenSSL
  library.  As in some special FIPS-140 build environments.

* bpo-27144: The "map()" and "as_completed()" iterators in
  "concurrent.futures" now avoid keeping a reference to yielded
  objects.

* bpo-10746: Fix ctypes producing wrong **PEP 3118** type codes for
  integer types.

* bpo-22536: The subprocess module now sets the filename when
  FileNotFoundError is raised on POSIX systems due to the executable
  or cwd not being found.

* bpo-31249: concurrent.futures: WorkItem.run() used by
  ThreadPoolExecutor now breaks a reference cycle between an exception
  object and the WorkItem object.

* bpo-31247: xmlrpc.server now explicitly breaks reference cycles
  when using sys.exc_info() in code handling exceptions.

* bpo-30102: The ssl and hashlib modules now call
  OPENSSL_add_all_algorithms_noconf() on OpenSSL < 1.1.0. The function
  detects CPU features and enables optimizations on some CPU
  architectures such as POWER8. Patch is based on research from
  Gustavo Serra Scalet.

* bpo-31185: Fixed miscellaneous errors in asyncio speedup module.

* bpo-31135: ttk: fix the destroy() method of LabeledScale and
  OptionMenu classes. Call the parent destroy() method even if the
  used attribute doesn't exist. The LabeledScale.destroy() method now
  also explicitly clears label and scale attributes to help the
  garbage collector to destroy all widgets.

* bpo-31107: Fix "copyreg._slotnames()" mangled attribute
  calculation for classes whose name begins with an underscore. Patch
  by Shane Harvey.

* bpo-31061: Fixed a crash when using asyncio and threads.

* bpo-30502: Fix handling of long oids in ssl.  Based on patch by
  Christian Heimes.

* bpo-30119: ftplib.FTP.putline() now throws ValueError on commands
  that contains CR or LF. Patch by Dong-hee Na.

* bpo-30595: multiprocessing.Queue.get() with a timeout now polls
  its reader in non-blocking mode if it succeeded to acquire the lock
  but the acquire took longer than the timeout.

* bpo-29403: Fix "unittest.mock"'s autospec to not fail on method-
  bound builtin functions.  Patch by Aaron Gallagher.

* bpo-30961: Fix decrementing a borrowed reference in tracemalloc.

* bpo-25684: Change "ttk.OptionMenu" radiobuttons to be unique
  across instances of "OptionMenu".

* bpo-30886: Fix multiprocessing.Queue.join_thread(): it now waits
  until the thread completes, even if the thread was started by the
  same process which created the queue.

* bpo-29854: Fix segfault in readline when using readline's history-
  size option.  Patch by Nir Soffer.

* bpo-30319: socket.close() now ignores ECONNRESET error.

* bpo-30828: Fix out of bounds write in
  "asyncio.CFuture.remove_done_callback()".

* bpo-30807: signal.setitimer() may disable the timer when passed a
  tiny value. Tiny values (such as 1e-6) are valid non-zero values for
  setitimer(), which is specified as taking microsecond-resolution
  intervals. However, on some platform, our conversion routine could
  convert 1e-6 into a zero interval, therefore disabling the timer
  instead of (re-)scheduling it.

* bpo-30441: Fix bug when modifying os.environ while iterating over
  it

* bpo-30532: Fix email header value parser dropping folding white
  space in certain cases.

* bpo-30879: os.listdir() and os.scandir() now emit bytes names when
  called with bytes-like argument.

* bpo-30746: Prohibited the '=' character in environment variable
  names in "os.putenv()" and "os.spawn*()".

* bpo-29755: Fixed the lgettext() family of functions in the gettext
  module. They now always return bytes.


文档
----

* bpo-31294: Fix incomplete code snippet in the ZeroMQSocketListener
  and ZeroMQSocketHandler examples and adapt them to Python 3.

* bpo-21649: Add RFC 7525 and Mozilla server side TLS links to SSL
  documentation.

* bpo-30803: Clarify doc on truth value testing. Original patch by
  Peter Thomassen.


测试
----

* bpo-31320: Silence traceback in test_ssl

* bpo-25674: Remove sha256.tbs-internet.com ssl test

* bpo-30715: Address ALPN callback changes for OpenSSL 1.1.0f. The
  latest version behaves like OpenSSL 1.0.2 and no longer aborts
  handshake.

* bpo-30822: regrtest: Exclude tzdata from regrtest --all. When
  running the test suite using --use=all / -u all, exclude tzdata
  since it makes test_datetime too slow (15-20 min on some buildbots)
  which then times out on some buildbots. Fix also regrtest command
  line parser to allow passing -u extralargefile to run
  test_zipfile64.


构建
----

* bpo-30854: Fix compile error when compiling --without-threads.
  Patch by Masayuki Yamamoto.


Windows
-------

* bpo-30389: Adds detection of Visual Studio 2017 to distutils on
  Windows.

* bpo-31340: Change to building with MSVC v141 (included with Visual
  Studio 2017)

* bpo-30581: os.cpu_count() now returns the correct number of
  processors on Windows when the number of logical processors is
  greater than 64.

* bpo-30731: Add a missing xmlns to python.manifest so that it
  matches the schema.


IDLE
----

* bpo-31493: IDLE code context -- fix code update and font update
  timers. Canceling timers prevents a warning message when test_idle
  completes.

* bpo-31488: IDLE - Update non-key options in former extension
  classes. When applying configdialog changes, call .reload for each
  feature class. Change ParenMatch so updated options affect existing
  instances attached to existing editor windows.

* bpo-31477: IDLE - Improve rstrip entry in doc. Strip trailing
  whitespace strips more than blank spaces.  Multiline string literals
  are not skipped.

* bpo-31480: IDLE - make tests pass with zzdummy extension disabled
  by default.

* bpo-31421: Document how IDLE runs tkinter programs. IDLE calls
  tcl/tk update in the background in order to make live interaction
  and experimentation with tkinter applications much easier.

* bpo-31414: IDLE -- fix tk entry box tests by deleting first.
  Adding to an int entry is not the same as deleting and inserting
  because int('') will fail.

* bpo-31051: Rearrange IDLE configdialog GenPage into Window,
  Editor, and Help sections.

* bpo-30617: IDLE - Add docstrings and tests for outwin subclass of
  editor. Move some data and functions from the class to module level.
  Patch by Cheryl Sabella.

* bpo-31287: IDLE - Do not modify tkinter.message in
  test_configdialog.

* bpo-27099: Convert IDLE's built-in 'extensions' to regular
  features. About 10 IDLE features were implemented as supposedly
  optional extensions. Their different behavior could be confusing or
  worse for users and not good for maintenance. Hence the conversion.
  The main difference for users is that user configurable key bindings
  for builtin features are now handled uniformly. Now, editing a
  binding in a keyset only affects its value in the keyset. All
  bindings are defined together in the system-specific default keysets
  in config- extensions.def. All custom keysets are saved as a whole
  in config- extension.cfg.  All take effect as soon as one clicks
  Apply or Ok. The affected events are '<<force-open-completions>>',
  '<<expand- word>>', '<<force-open-calltip>>', '<<flash-paren>>',
  '<<format- paragraph>>', '<<run-module>>', '<<check-module>>', and
  '<<zoom- height>>'.  Any (global) customizations made before 3.6.3
  will not affect their keyset-specific customization after 3.6.3. and
  vice versa. Initial patch by Charles Wohlganger.

* bpo-31206: IDLE: Factor HighPage(Frame) class from ConfigDialog.
  Patch by Cheryl Sabella.

* bpo-31001: Add tests for configdialog highlight tab.  Patch by
  Cheryl Sabella.

* bpo-31205: IDLE: Factor KeysPage(Frame) class from ConfigDialog.
  The slightly modified tests continue to pass.  Patch by Cheryl
  Sabella.

* bpo-31130: IDLE -- stop leaks in test_configdialog. Initial patch
  by Victor Stinner.

* bpo-31002: Add tests for configdialog keys tab. Patch by Cheryl
  Sabella.

* bpo-19903: IDLE: Calltips use "inspect.signature" instead of
  "inspect.getfullargspec". This improves calltips for builtins
  converted to use Argument Clinic. Patch by Louie Lu.

* bpo-31083: IDLE - Add an outline of a TabPage class in
  configdialog. Update existing classes to match outline. Initial
  patch by Cheryl Sabella.

* bpo-31050: Factor GenPage(Frame) class from ConfigDialog. The
  slightly modified tests continue to pass. Patch by Cheryl Sabella.

* bpo-31004: IDLE - Factor FontPage(Frame) class from ConfigDialog.
  Slightly modified tests continue to pass. Fix General tests. Patch
  mostly by Cheryl Sabella.

* bpo-30781: IDLE - Use ttk widgets in ConfigDialog. Patches by
  Terry Jan Reedy and Cheryl Sabella.

* bpo-31060: IDLE - Finish rearranging methods of ConfigDialog
  Grouping methods pertaining to each tab and the buttons will aid
  writing tests and improving the tabs and will enable splitting the
  groups into classes.

* bpo-30853: IDLE -- Factor a VarTrace class out of ConfigDialog.
  Instance tracers manages pairs consisting of a tk variable and a
  callback function. When tracing is turned on, setting the variable
  calls the function.  Test coverage for the new class is 100%.

* bpo-31003: IDLE: Add more tests for General tab.

* bpo-30993: IDLE - Improve configdialog font page and tests. In
  configdialog: Document causal pathways in create_font_tab docstring.
  Simplify some attribute names. Move set_samples calls to
  var_changed_font (idea from Cheryl Sabella).  Move related functions
  to positions after the create widgets function. In
  test_configdialog: Fix test_font_set so not order dependent.  Fix
  renamed test_indent_scale so it tests the widget. Adjust tests for
  movement of set_samples call.  Add tests for load functions.  Put
  all font tests in one class and tab indent tests in another.  Except
  for two lines, these tests completely cover the related functions.

* bpo-30981: IDLE -- Add more configdialog font page tests.

* bpo-28523: IDLE: replace 'colour' with 'color' in configdialog.

* bpo-30917: Add tests for idlelib.config.IdleConf. Increase
  coverage from 46% to 96%. Patch by Louie Lu.

* bpo-30934: Document coverage details for idlelib tests. Add
  section to idlelib/idle-test/README.txt. Include check that branches
  are taken both ways. Exclude IDLE-specific code that does not run
  during unit tests.

* bpo-30913: IDLE: Document ConfigDialog tk Vars, methods, and
  widgets in docstrings This will facilitate improving the dialog and
  splitting up the class. Original patch by Cheryl Sabella.

* bpo-30899: IDLE: Add tests for ConfigParser subclasses in config.
  Patch by Louie Lu.

* bpo-30881: IDLE: Add docstrings to browser.py. Patch by Cheryl
  Sabella.

* bpo-30851: IDLE: Remove unused variables in configdialog.  One is
  a duplicate, one is set but cannot be altered by users. Patch by
  Cheryl Sabella.

* bpo-30870: IDLE: In Settings dialog, select font with Up, Down
  keys as well as mouse. Initial patch by Louie Lu.

* bpo-8231: IDLE: call config.IdleConf.GetUserCfgDir only once.

* bpo-30779: IDLE: Factor ConfigChanges class from configdialog, put
  in config; test. * In config, put dump test code in a function; run
  it and unittest in   'if __name__ == '__main__'. * Add class
  config.ConfigChanges based on changes_class_v4.py on bpo issue. *
  Add class test_config.ChangesTest, partly using
  configdialog_tests_v1.py. * Revise configdialog to use
  ConfigChanges; see tracker msg297804. * Revise test_configdialog to
  match configdialog changes. * Remove configdialog functions unused
  or moved to ConfigChanges. Cheryl Sabella contributed parts of the
  patch.

* bpo-30777: IDLE: configdialog - Add docstrings and fix comments.
  Patch by Cheryl Sabella.

* bpo-30495: IDLE: Improve textview with docstrings, PEP8 names, and
  more tests. Patch by Cheryl Sabella.

* bpo-30723: IDLE: Make several improvements to parenmatch. Add
  'parens' style to highlight both opener and closer. Make 'default'
  style, which is not default, a synonym for 'opener'. Make time-delay
  work the same with all styles. Add help for config dialog extensions
  tab, including help for parenmatch. Add new tests.  Original patch
  by Charles Wohlganger.

* bpo-30674: IDLE: add docstrings to grep module. Patch by Cheryl
  Sabella

* bpo-21519: IDLE's basic custom key entry dialog now detects
  duplicates properly. Original patch by Saimadhav Heblikar.

* bpo-29910: IDLE no longer deletes a character after commenting out
  a region by a key shortcut.  Add "return 'break'" for this and other
  potential conflicts between IDLE and default key bindings.

* bpo-30728: Review and change idlelib.configdialog names. Lowercase
  method and attribute names. Replace 'colour' with 'color', expand
  overly cryptic names, delete unneeded underscores. Replace "import
  *" with specific imports. Patches by Cheryl Sabella.

* bpo-6739: IDLE: Verify user-entered key sequences by trying to
  bind them with tk. Add tests for all 3 validation functions.
  Original patch by G Polo.  Tests added by Cheryl Sabella.


工具/示例
---------

* bpo-30983: gdb integration commands (py-bt, etc.) work on
  optimized shared builds now, too.  **PEP 523** introduced
  _PyEval_EvalFrameDefault which inlines PyEval_EvalFrameEx on non-
  debug shared builds.  This broke the ability to use py-bt, py-up,
  and a few other Python-specific gdb integrations. The problem is
  fixed by only looking for _PyEval_EvalFrameDefault frames in python-
  gdb.py.  Original patch by Bruno "Polaco" Penteado.


Python 3.6.2 final
==================

*Release date: 2017-07-17*

No changes since release candidate 2


Python 3.6.2 release candidate 2
================================

*Release date: 2017-07-07*


安全
----

* bpo-30730: Prevent environment variables injection in subprocess
  on Windows.  Prevent passing other environment variables and command
  arguments.

* bpo-30694: Upgrade expat copy from 2.2.0 to 2.2.1 to get fixes of
  multiple security vulnerabilities including: CVE-2017-9233 (External
  entity infinite loop DoS), CVE-2016-9063 (Integer overflow, re-fix),
  CVE-2016-0718 (Fix regression bugs from 2.2.0's fix to
  CVE-2016-0718) and CVE-2012-0876 (Counter hash flooding with
  SipHash). Note: the CVE-2016-5300 (Use os-specific entropy sources
  like getrandom) doesn't impact Python, since Python already gets
  entropy from the OS to set the expat secret using
  "XML_SetHashSalt()".

* bpo-30500: Fix urllib.parse.splithost() to correctly parse
  fragments. For example, "splithost('//127.0.0.1#@evil.com/')" now
  correctly returns the "127.0.0.1" host, instead of treating
  "@evil.com" as the host in an authentication ("login@host").


Python 3.6.2 release candidate 1
================================

*Release date: 2017-06-17*


核心与内置
----------

* bpo-30682: Removed a too-strict assertion that failed for certain
  f-strings, such as eval("f'\n'") and eval("f'\r'").

* bpo-30604: Move co_extra_freefuncs to not be per-thread to avoid
  crashes

* bpo-29104: Fixed parsing backslashes in f-strings.

* bpo-27945: Fixed various segfaults with dict when input
  collections are mutated during searching, inserting or comparing.
  Based on patches by Duane Griffin and Tim Mitchell.

* bpo-25794: Fixed type.__setattr__() and type.__delattr__() for
  non- interned attribute names.  Based on patch by Eryk Sun.

* bpo-30039: If a KeyboardInterrupt happens when the interpreter is
  in the middle of resuming a chain of nested 'yield from' or 'await'
  calls, it's now correctly delivered to the innermost frame.

* bpo-12414: sys.getsizeof() on a code object now returns the sizes
  which includes the code struct and sizes of objects which it
  references. Patch by Dong-hee Na.

* bpo-29949: Fix memory usage regression of set and frozenset
  object.

* bpo-29935: Fixed error messages in the index() method of tuple,
  list and deque when pass indices of wrong type.

* bpo-29859: Show correct error messages when any of the pthread_*
  calls in thread_pthread.h fails.

* bpo-28876: "bool(range)" works even if "len(range)" raises
  "OverflowError".

* bpo-29600: Fix wrapping coroutine return values in StopIteration.

* bpo-28856: Fix an oversight that %b format for bytes should
  support objects follow the buffer protocol.

* bpo-29714: Fix a regression that bytes format may fail when
  containing zero bytes inside.

* bpo-29478: If max_line_length=None is specified while using the
  Compat32 policy, it is no longer ignored.  Patch by Mircea Cosbuc.


库
--

* bpo-30616: Functional API of enum allows to create empty enums.
  Patched by Dong-hee Na

* bpo-30038: Fix race condition between signal delivery and wakeup
  file descriptor. Patch by Nathaniel Smith.

* bpo-23894: lib2to3 now recognizes "rb'...'" and "f'...'" strings.

* bpo-23890: unittest.TestCase.assertRaises() now manually breaks a
  reference cycle to not keep objects alive longer than expected.

* bpo-30149: inspect.signature() now supports callables with
  variable- argument parameters wrapped with partialmethod. Patch by
  Dong-hee Na.

* bpo-30645: Fix path calculation in imp.load_package(), fixing it
  for cases when a package is only shipped with bytecodes. Patch by
  Alexandru Ardelean.

* bpo-29931: Fixed comparison check for ipaddress.ip_interface
  objects. Patch by Sanjay Sundaresan.

* bpo-30605: re.compile() no longer raises a BytesWarning when
  compiling a bytes instance with misplaced inline modifier.  Patch by
  Roy Williams.


安全
----

* bpo-29591: Update expat copy from 2.1.1 to 2.2.0 to get fixes of
  CVE-2016-0718 and CVE-2016-4472. See
  https://sourceforge.net/p/expat/bugs/537/ for more information.


库
--

* bpo-24484: Avoid race condition in multiprocessing cleanup (#2159)

* bpo-28994: The traceback no longer displayed for SystemExit raised
  in a callback registered by atexit.

* bpo-30508: Don't log exceptions if Task/Future "cancel()" method
  was called.

* bpo-28556: Updates to typing module: Add generic
  AsyncContextManager, add support for ContextManager on all versions.
  Original PRs by Jelle Zijlstra and Ivan Levkivskyi

* bpo-29870: Fix ssl sockets leaks when connection is aborted in
  asyncio/ssl implementation. Patch by Michaël Sghaïer.

* bpo-29743: Closing transport during handshake process leaks open
  socket. Patch by Nikolay Kim

* bpo-27585: Fix waiter cancellation in asyncio.Lock. Patch by
  Mathieu Sornay.

* bpo-30418: On Windows, subprocess.Popen.communicate() now also
  ignore EINVAL on stdin.write() if the child process is still running
  but closed the pipe.

* bpo-29822: inspect.isabstract() now works during
  __init_subclass__. Patch by Nate Soares.

* bpo-29581: ABCMeta.__new__ now accepts "**kwargs", allowing
  abstract base classes to use keyword parameters in
  __init_subclass__. Patch by Nate Soares.

* bpo-30557: faulthandler now correctly filters and displays
  exception codes on Windows

* bpo-30378: Fix the problem that logging.handlers.SysLogHandler
  cannot handle IPv6 addresses.

* bpo-29960: Preserve generator state when _random.Random.setstate()
  raises an exception. Patch by Bryan Olson.

* bpo-30414: multiprocessing.Queue._feed background running thread
  do not break from main loop on exception.

* bpo-30003: Fix handling escape characters in HZ codec.  Based on
  patch by Ma Lin.

* bpo-30301: Fix AttributeError when using SimpleQueue.empty() under
  *spawn* and *forkserver* start methods.

* bpo-30329: imaplib and poplib now catch the Windows socket
  WSAEINVAL error (code 10022) on shutdown(SHUT_RDWR): An invalid
  operation was attempted. This error occurs sometimes on SSL
  connections.

* bpo-30375: Warnings emitted when compile a regular expression now
  always point to the line in the user code.  Previously they could
  point into inners of the re module if emitted from inside of groups
  or conditionals.

* bpo-30048: Fixed "Task.cancel()" can be ignored when the task is
  running coroutine and the coroutine returned without any more
  "await".

* bpo-30266: contextlib.AbstractContextManager now supports anti-
  registration by setting __enter__ = None or __exit__ = None,
  following the pattern introduced in bpo-25958. Patch by Jelle
  Zijlstra.

* bpo-30298: Weaken the condition of deprecation warnings for inline
  modifiers. Now allowed several subsequential inline modifiers at the
  start of the pattern (e.g. "'(?i)(?s)...'").  In verbose mode
  whitespaces and comments now are allowed before and between inline
  modifiers (e.g. "'(?x) (?i) (?s)...'").

* bpo-29990: Fix range checking in GB18030 decoder.  Original patch
  by Ma Lin.

* bpo-26293: Change resulted because of zipfile breakage. (See also:
  bpo-29094)

* bpo-30243: Removed the __init__ methods of _json's scanner and
  encoder. Misusing them could cause memory leaks or crashes.  Now
  scanner and encoder objects are completely initialized in the
  __new__ methods.

* bpo-30185: Avoid KeyboardInterrupt tracebacks in forkserver helper
  process when Ctrl-C is received.

* bpo-28556: Various updates to typing module: add typing.NoReturn
  type, use WrapperDescriptorType, minor bug-fixes.  Original PRs by
  Jim Fasarakis-Hilliard and Ivan Levkivskyi.

* bpo-30205: Fix getsockname() for unbound AF_UNIX sockets on Linux.

* bpo-30070: Fixed leaks and crashes in errors handling in the
  parser module.

* bpo-30061: Fixed crashes in IOBase methods __next__() and
  readlines() when readline() or __next__() respectively return non-
  sizeable object. Fixed possible other errors caused by not checking
  results of PyObject_Size(), PySequence_Size(), or PyMapping_Size().

* bpo-30017: Allowed calling the close() method of the zip entry
  writer object multiple times.  Writing to a closed writer now always
  produces a ValueError.

* bpo-30068: _io._IOBase.readlines will check if it's closed first
  when hint is present.

* bpo-29694: Fixed race condition in pathlib mkdir with flags
  parents=True. Patch by Armin Rigo.

* bpo-29692: Fixed arbitrary unchaining of RuntimeError exceptions
  in contextlib.contextmanager.  Patch by Siddharth Velankar.

* bpo-29998: Pickling and copying ImportError now preserves name and
  path attributes.

* bpo-29953: Fixed memory leaks in the replace() method of datetime
  and time objects when pass out of bound fold argument.

* bpo-29942: Fix a crash in itertools.chain.from_iterable when
  encountering long runs of empty iterables.

* bpo-27863: Fixed multiple crashes in ElementTree caused by race
  conditions and wrong types.

* bpo-28699: Fixed a bug in pools in multiprocessing.pool that
  raising an exception at the very first of an iterable may swallow
  the exception or make the program hang. Patch by Davin Potts and
  Xiang Zhang.

* bpo-25803: Avoid incorrect errors raised by
  Path.mkdir(exist_ok=True) when the OS gives priority to errors such
  as EACCES over EEXIST.

* bpo-29861: Release references to tasks, their arguments and their
  results as soon as they are finished in multiprocessing.Pool.

* bpo-29884: faulthandler: Restore the old sigaltstack during
  teardown. Patch by Christophe Zeitouny.

* bpo-25455: Fixed crashes in repr of recursive buffered file-like
  objects.

* bpo-29800: Fix crashes in partial.__repr__ if the keys of
  partial.keywords are not strings.  Patch by Michael Seifert.

* bpo-29742: get_extra_info() raises exception if get called on
  closed ssl transport. Patch by Nikolay Kim.

* bpo-8256: Fixed possible failing or crashing input() if attributes
  "encoding" or "errors" of sys.stdin or sys.stdout are not set or are
  not strings.

* bpo-28298: Fix a bug that prevented array 'Q', 'L' and 'I' from
  accepting big intables (objects that have __int__) as elements.
  Patch by Oren Milman.

* bpo-28231: The zipfile module now accepts path-like objects for
  external paths.

* bpo-26915: index() and count() methods of collections.abc.Sequence
  now check identity before checking equality when do comparisons.

* bpo-29615: SimpleXMLRPCDispatcher no longer chains KeyError (or
  any other exception) to exception(s) raised in the dispatched
  methods. Patch by Petr Motejlek.

* bpo-30177: path.resolve(strict=False) no longer cuts the path
  after the first element not present in the filesystem.  Patch by
  Antoine Pietri.


IDLE
----

* bpo-15786: Fix several problems with IDLE's autocompletion box.
  The following should now work: clicking on selection box items;
  using the scrollbar; selecting an item by hitting Return. Hangs on
  MacOSX should no longer happen. Patch by Louie Lu.

* bpo-25514: Add doc subsubsection about IDLE failure to start.
  Popup no-connection message directs users to this section.

* bpo-30642: Fix reference leaks in IDLE tests. Patches by Louie Lu
  and Terry Jan Reedy.

* bpo-30495: Add docstrings for textview.py and use PEP8 names.
  Patches by Cheryl Sabella and Terry Jan Reedy.

* bpo-30290: Help-about: use pep8 names and add tests. Increase
  coverage to 100%. Patches by Louie Lu, Cheryl Sabella, and Terry Jan
  Reedy.

* bpo-30303: Add _utest option to textview; add new tests. Increase
  coverage to 100%. Patches by Louie Lu and Terry Jan Reedy.


C API
-----

* bpo-27867: Function PySlice_GetIndicesEx() no longer replaced with
  a macro if Py_LIMITED_API is not set.


构建
----

* bpo-29941: Add "--with-assertions" configure flag to explicitly
  enable C "assert()" checks. Defaults to off. "--with-pydebug"
  implies "--with-assertions".

* bpo-28787: Fix out-of-tree builds of Python when configured with
  "-- with--dtrace".

* bpo-29243: Prevent unnecessary rebuilding of Python during "make
  test", "make install" and some other make targets when configured
  with "--enable-optimizations".

* bpo-23404: Don't regenerate generated files based on file
  modification time anymore: the action is now explicit. Replace "make
  touch" with "make regen-all".

* bpo-29643: Fix "--enable-optimization" didn't work.


文档
----

* bpo-30176: Add missing attribute related constants in curses
  documentation.

* bpo-30052: the link targets for "bytes()" and "bytearray()" are
  now their respective type definitions, rather than the corresponding
  builtin function entries. Use bytes and bytearray to reference the
  latter. In order to ensure this and future cross-reference updates
  are applied automatically, the daily documentation builds now
  disable the default output caching features in Sphinx.

* bpo-26985: Add missing info of code object in inspect
  documentation.


工具/示例
---------

* bpo-29367: python-gdb.py now supports also "method-wrapper"
  ("wrapperobject") objects.


测试
----

* bpo-30357: test_thread: setUp() now uses support.threading_setup()
  and support.threading_cleanup() to wait until threads complete to
  avoid random side effects on following tests. Initial patch written
  by Grzegorz Grzywacz.

* bpo-30197: Enhanced functions swap_attr() and swap_item() in the
  test.support module. They now work when delete replaced attribute or
  item inside the with statement.  The old value of the attribute or
  item (or None if it doesn't exist) now will be assigned to the
  target of the "as" clause, if there is one.


Windows
-------

* bpo-30687: Locate msbuild.exe on Windows when building rather than
  vcvarsall.bat

* bpo-30450: The build process on Windows no longer depends on
  Subversion, instead pulling external code from GitHub via a Python
  script.  If Python 3.6 is not found on the system (via "py -3.6"),
  NuGet is used to download a copy of 32-bit Python.


Python 3.6.1 final
==================

*Release date: 2017-03-21*


核心与内置
----------

* bpo-29723: The "sys.path[0]" initialization change for bpo-29139
  caused a regression by revealing an inconsistency in how sys.path is
  initialized when executing "__main__" from a zipfile, directory, or
  other import location. The interpreter now consistently avoids ever
  adding the import location's parent directory to "sys.path", and
  ensures no other "sys.path" entries are inadvertently modified when
  inserting the import location named on the command line.


构建
----

* bpo-27593: fix format of git information used in sys.version

* Fix incompatible comment in python.h


Python 3.6.1 release candidate 1
================================

*Release date: 2017-03-04*


核心与内置
----------

* bpo-28893: Set correct __cause__ for errors about invalid
  awaitables returned from __aiter__ and __anext__.

* bpo-29683: Fixes to memory allocation in _PyCode_SetExtra.  Patch
  by Brian Coleman.

* bpo-29684: Fix minor regression of PyEval_CallObjectWithKeywords.
  It should raise TypeError when kwargs is not a dict.  But it might
  cause segv when args=NULL and kwargs is not a dict.

* bpo-28598: Support __rmod__ for subclasses of str being called
  before str.__mod__. Patch by Martijn Pieters.

* bpo-29607: Fix stack_effect computation for CALL_FUNCTION_EX.
  Patch by Matthieu Dartiailh.

* bpo-29602: Fix incorrect handling of signed zeros in complex
  constructor for complex subclasses and for inputs having a
  __complex__ method. Patch by Serhiy Storchaka.

* bpo-29347: Fixed possibly dereferencing undefined pointers when
  creating weakref objects.

* bpo-29438: Fixed use-after-free problem in key sharing dict.

* bpo-29319: Prevent RunMainFromImporter overwriting sys.path[0].

* bpo-29337: Fixed possible BytesWarning when compare the code
  objects. Warnings could be emitted at compile time.

* bpo-29327: Fixed a crash when pass the iterable keyword argument
  to sorted().

* bpo-29034: Fix memory leak and use-after-free in os module
  (path_converter).

* bpo-29159: Fix regression in bytes(x) when x.__index__() raises
  Exception.

* bpo-28932: Do not include <sys/random.h> if it does not exist.

* bpo-25677: Correct the positioning of the syntax error caret for
  indented blocks. Based on patch by Michael Layzell.

* bpo-29000: Fixed bytes formatting of octals with zero padding in
  alternate form.

* bpo-26919: On Android, operating system data is now always
  encoded/decoded to/from UTF-8, instead of the locale encoding to
  avoid inconsistencies with os.fsencode() and os.fsdecode() which are
  already using UTF-8.

* bpo-28991: functools.lru_cache() was susceptible to an obscure
  reentrancy bug triggerable by a monkey-patched len() function.

* bpo-28739: f-string expressions are no longer accepted as
  docstrings and by ast.literal_eval() even if they do not include
  expressions.

* bpo-28512: Fixed setting the offset attribute of SyntaxError by
  PyErr_SyntaxLocationEx() and PyErr_SyntaxLocationObject().

* bpo-28918: Fix the cross compilation of xxlimited when Python has
  been built with Py_DEBUG defined.

* bpo-28731: Optimize _PyDict_NewPresized() to create correct size
  dict. Improve speed of dict literal with constant keys up to 30%.


库
--

* bpo-29169: Update zlib to 1.2.11.

* bpo-29623: Allow use of path-like object as a single argument in
  ConfigParser.read(). Patch by David Ellis.

* bpo-28963: Fix out of bound iteration in
  asyncio.Future.remove_done_callback implemented in C.

* bpo-29704: asyncio.subprocess.SubprocessStreamProtocol no longer
  closes before all pipes are closed.

* bpo-29271: Fix Task.current_task and Task.all_tasks implemented in
  C to accept None argument as their pure Python implementation.

* bpo-29703: Fix asyncio to support instantiation of new event loops
  in child processes.

* bpo-29376: Fix assertion error in
  threading._DummyThread.is_alive().

* bpo-28624: Add a test that checks that cwd parameter of Popen()
  accepts PathLike objects.  Patch by Sayan Chowdhury.

* bpo-28518: Start a transaction implicitly before a DML statement.
  Patch by Aviv Palivoda.

* bpo-29532: Altering a kwarg dictionary passed to
  functools.partial() no longer affects a partial object after
  creation.

* bpo-29110: Fix file object leak in aifc.open() when file is given
  as a filesystem path and is not in valid AIFF format. Patch by
  Anthony Zhang.

* bpo-28556: Various updates to typing module: typing.Counter,
  typing.ChainMap, improved ABC caching, etc. Original PRs by Jelle
  Zijlstra, Ivan Levkivskyi, Manuel Krebber, and Łukasz Langa.

* bpo-29100: Fix datetime.fromtimestamp() regression introduced in
  Python 3.6.0: check minimum and maximum years.

* bpo-29519: Fix weakref spewing exceptions during interpreter
  shutdown when used with a rare combination of multiprocessing and
  custom codecs.

* bpo-29416: Prevent infinite loop in pathlib.Path.mkdir

* bpo-29444: Fixed out-of-bounds buffer access in the group() method
  of the match object. Based on patch by WGH.

* bpo-29335: Fix subprocess.Popen.wait() when the child process has
  exited to a stopped instead of terminated state (ex: when under
  ptrace).

* bpo-29290: Fix a regression in argparse that help messages would
  wrap at non-breaking spaces.

* bpo-28735: Fixed the comparison of mock.MagickMock with mock.ANY.

* bpo-29316: Restore the provisional status of typing module, add
  corresponding note to documentation. Patch by Ivan L.

* bpo-29219: Fixed infinite recursion in the repr of uninitialized
  ctypes.CDLL instances.

* bpo-29011: Fix an important omission by adding Deque to the typing
  module.

* bpo-28969: Fixed race condition in C implementation of
  functools.lru_cache. KeyError could be raised when cached function
  with full cache was simultaneously called from different threads
  with the same uncached arguments.

* bpo-29142: In urllib.request, suffixes in no_proxy environment
  variable with leading dots could match related hostnames again (e.g.
  .b.c matches a.b.c). Patch by Milan Oberkirch.

* bpo-28961: Fix unittest.mock._Call helper: don't ignore the name
  parameter anymore. Patch written by Jiajun Huang.

* bpo-29203: functools.lru_cache() now respects **PEP 468** and
  preserves the order of keyword arguments.  f(a=1, b=2) is now cached
  separately from f(b=2, a=1) since both calls could potentially give
  different results.

* bpo-15812: inspect.getframeinfo() now correctly shows the first
  line of a context. Patch by Sam Breese.

* bpo-29094: Offsets in a ZIP file created with extern file object
  and modes "w" and "x" now are relative to the start of the file.

* bpo-29085: Allow random.Random.seed() to use high quality OS
  randomness rather than the pid and time.

* bpo-29061: Fixed bug in secrets.randbelow() which would hang when
  given a negative input.  Patch by Brendan Donegan.

* bpo-29079: Prevent infinite loop in pathlib.resolve() on Windows

* bpo-13051: Fixed recursion errors in large or resized
  curses.textpad.Textbox.  Based on patch by Tycho Andersen.

* bpo-29119: Fix weakrefs in the pure python version of
  collections.OrderedDict move_to_end() method. Contributed by Andra
  Bogildea.

* bpo-9770: curses.ascii predicates now work correctly with negative
  integers.

* bpo-28427: old keys should not remove new values from
  WeakValueDictionary when collecting from another thread.

* bpo-28923: Remove editor artifacts from Tix.py.

* bpo-29055: Neaten-up empty population error on random.choice() by
  suppressing the upstream exception.

* bpo-28871: Fixed a crash when deallocate deep ElementTree.

* bpo-19542: Fix bugs in WeakValueDictionary.setdefault() and
  WeakValueDictionary.pop() when a GC collection happens in another
  thread.

* bpo-20191: Fixed a crash in resource.prlimit() when passing a
  sequence that doesn't own its elements as limits.

* bpo-28779: multiprocessing.set_forkserver_preload() would crash
  the forkserver process if a preloaded module instantiated some
  multiprocessing objects such as locks.

* bpo-28847: dbm.dumb now supports reading read-only files and no
  longer writes the index file when it is not changed.

* bpo-26937: The chown() method of the tarfile.TarFile class does
  not fail now when the grp module cannot be imported, as for example
  on Android platforms.


IDLE
----

* bpo-29071: IDLE colors f-string prefixes (but not invalid ur
  prefixes).

* bpo-28572: Add 10% to coverage of IDLE's test_configdialog. Update
  and augment description of the configuration system.


Windows
-------

* bpo-29579: Removes readme.txt from the installer

* bpo-29326: Ignores blank lines in ._pth files (Patch by Alexey
  Izbyshev)

* bpo-28164: Correctly handle special console filenames (patch by
  Eryk Sun)

* bpo-29409: Implement **PEP 529** for io.FileIO (Patch by Eryk Sun)

* bpo-29392: Prevent crash when passing invalid arguments into
  msvcrt module.

* bpo-25778: winreg does not truncate string correctly (Patch by
  Eryk Sun)

* bpo-28896: Deprecate WindowsRegistryFinder and disable it by
  default.


C API
-----

* bpo-27867: Function PySlice_GetIndicesEx() is replaced with a
  macro if Py_LIMITED_API is not set or set to the value between
  0x03050400 and 0x03060000 (not including) or 0x03060100 or higher.

* bpo-29083: Fixed the declaration of some public API functions.
  PyArg_VaParse() and PyArg_VaParseTupleAndKeywords() were not
  available in limited API. PyArg_ValidateKeywordArguments(),
  PyArg_UnpackTuple() and Py_BuildValue() were not available in
  limited API of version < 3.3 when PY_SSIZE_T_CLEAN is defined.

* bpo-29058: All stable API extensions added after Python 3.2 are
  now available only when Py_LIMITED_API is set to the PY_VERSION_HEX
  value of the minimum Python version supporting this API.


文档
----

* bpo-28929: Link the documentation to its source file on GitHub.

* bpo-25008: Document smtpd.py as effectively deprecated and add a
  pointer to aiosmtpd, a third-party asyncio-based replacement.

* bpo-26355: Add canonical header link on each page to corresponding
  major version of the documentation. Patch by Matthias Bussonnier.

* bpo-29349: Fix Python 2 syntax in code for building the
  documentation.


测试
----

* bpo-28087: Skip test_asyncore and test_eintr poll failures on
  macOS. Skip some tests of select.poll when running on macOS due to
  unresolved issues with the underlying system poll function on some
  macOS versions.

* bpo-29571: to match the behaviour of the "re.LOCALE" flag,
  test_re.test_locale_flag now uses
  "locale.getpreferredencoding(False)" to determine the candidate
  encoding for the test regex (allowing it to correctly skip the test
  when the default locale encoding is a multi-byte encoding)

* bpo-28950: Disallow -j0 to be combined with -T/-l in regrtest
  command line arguments.

* bpo-28683: Fix the tests that bind() a unix socket and raise
  PermissionError on Android for a non-root user.

* bpo-26939: Add the support.setswitchinterval() function to fix
  test_functools hanging on the Android armv7 qemu emulator.


构建
----

* bpo-27593: sys.version and the platform module python_build(),
  python_branch(), and python_revision() functions now use git
  information rather than hg when building from a repo.

* bpo-29572: Update Windows build and OS X installers to use OpenSSL
  1.0.2k.

* bpo-26851: Set Android compilation and link flags.

* bpo-28768: Fix implicit declaration of function _setmode. Patch by
  Masayuki Yamamoto

* bpo-29080: Removes hard dependency on hg.exe from
  PCBuild/build.bat

* bpo-23903: Added missed names to PC/python3.def.

* bpo-28762: lockf() is available on Android API level 24, but the
  F_LOCK macro is not defined in android-ndk-r13.

* bpo-28538: Fix the compilation error that occurs because
  if_nameindex() is available on Android API level 24, but the
  if_nameindex structure is not defined.

* bpo-20211: Do not add the directory for installing C header files
  and the directory for installing object code libraries to the cross
  compilation search paths. Original patch by Thomas Petazzoni.

* bpo-28849: Do not define sys.implementation._multiarch on Android.


Python 3.6.0 final
==================

*Release date: 2016-12-23*

No changes since release candidate 2


Python 3.6.0 release candidate 2
================================

*Release date: 2016-12-16*


核心与内置
----------

* bpo-28147: Fix a memory leak in split-table dictionaries:
  setattr() must not convert combined table into split table. Patch
  written by INADA Naoki.

* bpo-28990: Fix asyncio SSL hanging if connection is closed before
  handshake is completed. (Patch by HoHo-Ho)


工具/示例
---------

* bpo-28770: Fix python-gdb.py for fastcalls.


Windows
-------

* bpo-28896: Deprecate WindowsRegistryFinder.


构建
----

* bpo-28898: Prevent gdb build errors due to HAVE_LONG_LONG
  redefinition.


Python 3.6.0 release candidate 1
================================

*Release date: 2016-12-06*


核心与内置
----------

* bpo-23722: Rather than silently producing a class that doesn't
  support zero-argument "super()" in methods, failing to pass the new
  "__classcell__" namespace entry up to "type.__new__" now results in
  a "DeprecationWarning" and a class that supports zero-argument
  "super()".

* bpo-28797: Modifying the class __dict__ inside the __set_name__
  method of a descriptor that is used inside that class no longer
  prevents calling the __set_name__ method of other descriptors.

* bpo-28782: Fix a bug in the implementation "yield from" when
  checking if the next instruction is YIELD_FROM. Regression
  introduced by WORDCODE (bpo-26647).


库
--

* bpo-27030: Unknown escapes in re.sub() replacement template are
  allowed again.  But they still are deprecated and will be disabled
  in 3.7.

* bpo-28835: Fix a regression introduced in
  warnings.catch_warnings(): call warnings.showwarning() if it was
  overridden inside the context manager.

* bpo-27172: To assist with upgrades from 2.7, the previously
  documented deprecation of "inspect.getfullargspec()" has been
  reversed. This decision may be revisited again after the Python 2.7
  branch is no longer officially supported.

* bpo-26273: Add new "socket.TCP_CONGESTION" (Linux 2.6.13) and
  "socket.TCP_USER_TIMEOUT" (Linux 2.6.37) constants. Patch written by
  Omar Sandoval.

* bpo-24142: Reading a corrupt config file left configparser in an
  invalid state. Original patch by Florian Höch.

* bpo-28843: Fix asyncio C Task to handle exceptions __traceback__.


C API
-----

* bpo-28808: PyUnicode_CompareWithASCIIString() now never raises
  exceptions.


文档
----

* bpo-23722: The data model reference and the porting section in the
  What's New guide now cover the additional "__classcell__" handling
  needed for custom metaclasses to fully support **PEP 487** and zero-
  argument "super()".


工具/示例
---------

* bpo-28023: Fix python-gdb.py didn't support new dict
  implementation.


Python 3.6.0 beta 4
===================

*Release date: 2016-11-21*


核心与内置
----------

* bpo-28532: Show sys.version when -V option is supplied twice.

* bpo-27100: The with-statement now checks for __enter__ before it
  checks for __exit__. This gives less confusing error messages when
  both methods are missing. Patch by Jonathan Ellington.

* bpo-28746: Fix the set_inheritable() file descriptor method on
  platforms that do not have the ioctl FIOCLEX and FIONCLEX commands.

* bpo-26920: Fix not getting the locale's charset upon initializing
  the interpreter, on platforms that do not have langinfo.

* bpo-28648: Fixed crash in Py_DecodeLocale() in debug build on Mac
  OS X when decode astral characters.  Patch by Xiang Zhang.

* bpo-19398: Extra slash no longer added to sys.path components in
  case of empty compile-time PYTHONPATH components.

* bpo-28665: Improve speed of the STORE_DEREF opcode by 40%.

* bpo-28583: PyDict_SetDefault didn't combine split table when
  needed. Patch by Xiang Zhang.

* bpo-27243: Change PendingDeprecationWarning -> DeprecationWarning.
  As it was agreed in the issue, __aiter__ returning an awaitable
  should result in PendingDeprecationWarning in 3.5 and in
  DeprecationWarning in 3.6.

* bpo-26182: Fix a refleak in code that raises DeprecationWarning.

* bpo-28721: Fix asynchronous generators aclose() and athrow() to
  handle StopAsyncIteration propagation properly.


库
--

* bpo-28752: Restored the __reduce__() methods of datetime objects.

* bpo-28727: Regular expression patterns, _sre.SRE_Pattern objects
  created by re.compile(), become comparable (only x==y and x!=y
  operators). This change should fix the bpo-18383: don't duplicate
  warning filters when the warnings module is reloaded (thing usually
  only done in unit tests).

* bpo-20572: The subprocess.Popen.wait method's undocumented endtime
  parameter now raises a DeprecationWarning.

* bpo-25659: In ctypes, prevent a crash calling the from_buffer()
  and from_buffer_copy() methods on abstract classes like Array.

* bpo-19717: Makes Path.resolve() succeed on paths that do not
  exist. Patch by Vajrasky Kok

* bpo-28563: Fixed possible DoS and arbitrary code execution when
  handle plural form selections in the gettext module.  The expression
  parser now supports exact syntax supported by GNU gettext.

* bpo-28387: Fixed possible crash in _io.TextIOWrapper deallocator
  when the garbage collector is invoked in other thread.  Based on
  patch by Sebastian Cufre.

* bpo-28600: Optimize loop.call_soon.

* bpo-28613: Fix get_event_loop() return the current loop if called
  from coroutines/callbacks.

* bpo-28634: Fix asyncio.isfuture() to support unittest.Mock.

* bpo-26081: Fix refleak in _asyncio.Future.__iter__().throw.

* bpo-28639: Fix inspect.isawaitable to always return bool Patch by
  Justin Mayfield.

* bpo-28652: Make loop methods reject socket kinds they do not
  support.

* bpo-28653: Fix a refleak in functools.lru_cache.

* bpo-28703: Fix asyncio.iscoroutinefunction to handle Mock objects.

* bpo-28704: Fix create_unix_server to support Path-like objects
  (PEP 519).

* bpo-28720: Add collections.abc.AsyncGenerator.


文档
----

* bpo-28513: Documented command-line interface of zipfile.


测试
----

* bpo-28666: Now test.support.rmtree is able to remove unwritable or
  unreadable directories.

* bpo-23839: Various caches now are cleared before running every
  test file.


构建
----

* bpo-10656: Fix out-of-tree building on AIX.  Patch by Tristan
  Carel and Michael Haubenwallner.

* bpo-26359: Rename --with-optimiations to --enable-optimizations.

* bpo-28676: Prevent missing 'getentropy' declaration warning on
  macOS. Patch by Gareth Rees.


Python 3.6.0 beta 3
===================

*Release date: 2016-10-31*


核心与内置
----------

* bpo-28128: Deprecation warning for invalid str and byte escape
  sequences now prints better information about where the error
  occurs. Patch by Serhiy Storchaka and Eric Smith.

* bpo-28509: dict.update() no longer allocate unnecessary large
  memory.

* bpo-28426: Fixed potential crash in PyUnicode_AsDecodedObject() in
  debug build.

* bpo-28517: Fixed of-by-one error in the peephole optimizer that
  caused keeping unreachable code.

* bpo-28214: Improved exception reporting for problematic
  __set_name__ attributes.

* bpo-23782: Fixed possible memory leak in _PyTraceback_Add() and
  exception loss in PyTraceBack_Here().

* bpo-28471: Fix "Python memory allocator called without holding the
  GIL" crash in socket.setblocking.


库
--

* bpo-27517: LZMA compressor and decompressor no longer raise
  exceptions if given empty data twice.  Patch by Benjamin Fogle.

* bpo-28549: Fixed segfault in curses's addch() with ncurses6.

* bpo-28449: tarfile.open() with mode "r" or "r:" now tries to open
  a tar file with compression before trying to open it without
  compression. Otherwise it had 50% chance failed with
  ignore_zeros=True.

* bpo-23262: The webbrowser module now supports Firefox 36+ and
  derived browsers.  Based on patch by Oleg Broytman.

* bpo-27939: Fixed bugs in tkinter.ttk.LabeledScale and
  tkinter.Scale caused by representing the scale as float value
  internally in Tk. tkinter.IntVar now works if float value is set to
  underlying Tk variable.

* bpo-18844: The various ways of specifying weights for
  random.choices() now produce the same result sequences.

* bpo-28255: calendar.TextCalendar().prmonth() no longer prints a
  space at the start of new line after printing a month's calendar.
  Patch by Xiang Zhang.

* bpo-20491: The textwrap.TextWrapper class now honors non-breaking
  spaces. Based on patch by Kaarle Ritvanen.

* bpo-28353: os.fwalk() no longer fails on broken links.

* bpo-28430: Fix iterator of C implemented asyncio.Future doesn't
  accept non-None value is passed to it.send(val).

* bpo-27025: Generated names for Tkinter widgets now start by the
  "!" prefix for readability.

* bpo-25464: Fixed HList.header_exists() in tkinter.tix module by
  addin a workaround to Tix library bug.

* bpo-28488: shutil.make_archive() no longer adds entry "./" to ZIP
  archive.

* bpo-25953: re.sub() now raises an error for invalid numerical
  group reference in replacement template even if the pattern is not
  found in the string.  Error message for invalid group reference now
  includes the group index and the position of the reference. Based on
  patch by SilentGhost.

* bpo-18219: Optimize csv.DictWriter for large number of columns.
  Patch by Mariatta Wijaya.

* bpo-28448: Fix C implemented asyncio.Future didn't work on
  Windows.

* bpo-28480: Fix error building socket module when multithreading is
  disabled.

* bpo-24452: Make webbrowser support Chrome on Mac OS X.

* bpo-20766: Fix references leaked by pdb in the handling of SIGINT
  handlers.

* bpo-28492: Fix how StopIteration exception is raised in
  _asyncio.Future.

* bpo-28500: Fix asyncio to handle async gens GC from another
  thread.

* bpo-26923: Fix asyncio.Gather to refuse being cancelled once all
  children are done. Patch by Johannes Ebke.

* bpo-26796: Don't configure the number of workers for default
  threadpool executor. Initial patch by Hans Lawrenz.

* bpo-28544: Implement asyncio.Task in C.


Windows
-------

* bpo-28522: Fixes mishandled buffer reallocation in getpathp.c


构建
----

* bpo-28444: Fix missing extensions modules when cross compiling.

* bpo-28208: Update Windows build and OS X installers to use SQLite
  3.14.2.

* bpo-28248: Update Windows build and OS X installers to use OpenSSL
  1.0.2j.


测试
----

* bpo-26944: Fix test_posix for Android where 'id -G' is entirely
  wrong or missing the effective gid.

* bpo-28409: regrtest: fix the parser of command line arguments.


Python 3.6.0 beta 2
===================

*Release date: 2016-10-10*


核心与内置
----------

* bpo-28183: Optimize and cleanup dict iteration.

* bpo-26081: Added C implementation of asyncio.Future. Original
  patch by Yury Selivanov.

* bpo-28379: Added sanity checks and tests for
  PyUnicode_CopyCharacters(). Patch by Xiang Zhang.

* bpo-28376: The type of long range iterator is now registered as
  Iterator. Patch by Oren Milman.

* bpo-28376: Creating instances of range_iterator by calling
  range_iterator type now is deprecated.  Patch by Oren Milman.

* bpo-28376: The constructor of range_iterator now checks that step
  is not 0. Patch by Oren Milman.

* bpo-26906: Resolving special methods of uninitialized type now
  causes implicit initialization of the type instead of a fail.

* bpo-18287: PyType_Ready() now checks that tp_name is not NULL.
  Original patch by Niklas Koep.

* bpo-24098: Fixed possible crash when AST is changed in process of
  compiling it.

* bpo-28201: Dict reduces possibility of 2nd conflict in hash table
  when hashes have same lower bits.

* bpo-28350: String constants with null character no longer
  interned.

* bpo-26617: Fix crash when GC runs during weakref callbacks.

* bpo-27942: String constants now interned recursively in tuples and
  frozensets.

* bpo-21578: Fixed misleading error message when ImportError called
  with invalid keyword args.

* bpo-28203: Fix incorrect type in complex(1.0, {2:3}) error
  message. Patch by Soumya Sharma.

* bpo-28086: Single var-positional argument of tuple subtype was
  passed unscathed to the C-defined function.  Now it is converted to
  exact tuple.

* bpo-28214: Now __set_name__ is looked up on the class instead of
  the instance.

* bpo-27955: Fallback on reading /dev/urandom device when the
  getrandom() syscall fails with EPERM, for example when blocked by
  SECCOMP.

* bpo-28192: Don't import readline in isolated mode.

* Upgrade internal unicode databases to Unicode version 9.0.0.

* bpo-28131: Fix a regression in zipimport's compile_source().
  zipimport should use the same optimization level as the interpreter.

* bpo-28126: Replace Py_MEMCPY with memcpy(). Visual Studio can
  properly optimize memcpy().

* bpo-28120: Fix dict.pop() for splitted dictionary when trying to
  remove a "pending key" (Not yet inserted in split-table). Patch by
  Xiang Zhang.

* bpo-26182: Raise DeprecationWarning when async and await keywords
  are used as variable/attribute/class/function name.


库
--

* bpo-27998: Fixed bytes path support in os.scandir() on Windows.
  Patch by Eryk Sun.

* bpo-28317: The disassembler now decodes FORMAT_VALUE argument.

* bpo-26293: Fixed writing ZIP files that starts not from the start
  of the file.  Offsets in ZIP file now are relative to the start of
  the archive in conforming to the specification.

* bpo-28380: unittest.mock Mock autospec functions now properly
  support assert_called, assert_not_called, and assert_called_once.

* bpo-27181: remove statistics.geometric_mean and defer until 3.7.

* bpo-28229: lzma module now supports pathlib.

* bpo-28321: Fixed writing non-BMP characters with binary format in
  plistlib.

* bpo-28225: bz2 module now supports pathlib.  Initial patch by
  Ethan Furman.

* bpo-28227: gzip now supports pathlib.  Patch by Ethan Furman.

* bpo-27358: Optimized merging var-keyword arguments and improved
  error message when passing a non-mapping as a var-keyword argument.

* bpo-28257: Improved error message when passing a non-iterable as a
  var-positional argument.  Added opcode BUILD_TUPLE_UNPACK_WITH_CALL.

* bpo-28322: Fixed possible crashes when unpickle itertools objects
  from incorrect pickle data.  Based on patch by John Leitch.

* bpo-28228: imghdr now supports pathlib.

* bpo-28226: compileall now supports pathlib.

* bpo-28314: Fix function declaration (C flags) for the
  getiterator() method of xml.etree.ElementTree.Element.

* bpo-28148: Stop using localtime() and gmtime() in the time module.
  Introduced platform independent _PyTime_localtime API that is
  similar to POSIX localtime_r, but available on all platforms.  Patch
  by Ed Schouten.

* bpo-28253: Fixed calendar functions for extreme months: 0001-01
  and 9999-12. Methods itermonthdays() and itermonthdays2() are
  reimplemented so that they don't call itermonthdates() which can
  cause datetime.date under/overflow.

* bpo-28275: Fixed possible use after free in the decompress()
  methods of the LZMADecompressor and BZ2Decompressor classes.
  Original patch by John Leitch.

* bpo-27897: Fixed possible crash in
  sqlite3.Connection.create_collation() if pass invalid string-like
  object as a name.  Patch by Xiang Zhang.

* bpo-18844: random.choices() now has k as a keyword-only argument
  to improve the readability of common cases and come into line with
  the signature used in other languages.

* bpo-18893: Fix invalid exception handling in
  Lib/ctypes/macholib/dyld.py. Patch by Madison May.

* bpo-27611: Fixed support of default root window in the tkinter.tix
  module. Added the master parameter in the DisplayStyle constructor.

* bpo-27348: In the traceback module, restore the formatting of
  exception messages like "Exception: None".  This fixes a regression
  introduced in 3.5a2.

* bpo-25651: Allow falsy values to be used for msg parameter of
  subTest().

* bpo-27778: Fix a memory leak in os.getrandom() when the
  getrandom() is interrupted by a signal and a signal handler raises a
  Python exception.

* bpo-28200: Fix memory leak on Windows in the os module (fix
  path_converter() function).

* bpo-25400: RobotFileParser now correctly returns default values
  for crawl_delay and request_rate.  Initial patch by Peter Wirtz.

* bpo-27932: Prevent memory leak in win32_ver().

* Fix UnboundLocalError in socket._sendfile_use_sendfile.

* bpo-28075: Check for ERROR_ACCESS_DENIED in Windows implementation
  of os.stat().  Patch by Eryk Sun.

* bpo-22493: Warning message emitted by using inline flags in the
  middle of regular expression now contains a (truncated) regex
  pattern. Patch by Tim Graham.

* bpo-25270: Prevent codecs.escape_encode() from raising SystemError
  when an empty bytestring is passed.

* bpo-28181: Get antigravity over HTTPS. Patch by Kaartic Sivaraam.

* bpo-25895: Enable WebSocket URL schemes in urllib.parse.urljoin.
  Patch by Gergely Imreh and Markus Holtermann.

* bpo-28114: Fix a crash in parse_envlist() when env contains byte
  strings. Patch by Eryk Sun.

* bpo-27599: Fixed buffer overrun in binascii.b2a_qp() and
  binascii.a2b_qp().

* bpo-27906: Fix socket accept exhaustion during high TCP traffic.
  Patch by Kevin Conway.

* bpo-28174: Handle when SO_REUSEPORT isn't properly supported.
  Patch by Seth Michael Larson.

* bpo-26654: Inspect functools.partial in asyncio.Handle.__repr__.
  Patch by iceboy.

* bpo-26909: Fix slow pipes IO in asyncio. Patch by INADA Naoki.

* bpo-28176: Fix callbacks race in
  asyncio.SelectorLoop.sock_connect.

* bpo-27759: Fix selectors incorrectly retain invalid file
  descriptors. Patch by Mark Williams.

* bpo-28368: Refuse monitoring processes if the child watcher has no
  loop attached. Patch by Vincent Michel.

* bpo-28369: Raise RuntimeError when transport's FD is used with
  add_reader, add_writer, etc.

* bpo-28370: Speedup asyncio.StreamReader.readexactly. Patch by
  Коренберг Марк.

* bpo-28371: Deprecate passing asyncio.Handles to run_in_executor.

* bpo-28372: Fix asyncio to support formatting of non-python
  coroutines.

* bpo-28399: Remove UNIX socket from FS before binding. Patch by
  Коренберг Марк.

* bpo-27972: Prohibit Tasks to await on themselves.


Windows
-------

* bpo-28402: Adds signed catalog files for stdlib on Windows.

* bpo-28333: Enables Unicode for ps1/ps2 and input() prompts. (Patch
  by Eryk Sun)

* bpo-28251: Improvements to help manuals on Windows.

* bpo-28110: launcher.msi has different product codes between 32-bit
  and 64-bit

* bpo-28161: Opening CON for write access fails

* bpo-28162: WindowsConsoleIO readall() fails if first line starts
  with Ctrl+Z

* bpo-28163: WindowsConsoleIO fileno() passes wrong flags to
  _open_osfhandle

* bpo-28164: _PyIO_get_console_type fails for various paths

* bpo-28137: Renames Windows path file to ._pth

* bpo-28138: Windows ._pth file should allow import site


C API
-----

* bpo-28426: Deprecated undocumented functions
  PyUnicode_AsEncodedObject(), PyUnicode_AsDecodedObject(),
  PyUnicode_AsDecodedUnicode() and PyUnicode_AsEncodedUnicode().


构建
----

* bpo-28258: Fixed build with Estonian locale (python-config and
  distclean targets in Makefile).  Patch by Arfrever Frehtes Taifersar
  Arahesis.

* bpo-26661: setup.py now detects system libffi with multiarch
  wrapper.

* bpo-15819: Remove redundant include search directory option for
  building outside the source tree.


测试
----

* bpo-28217: Adds _testconsole module to test console input.


Python 3.6.0 beta 1
===================

*Release date: 2016-09-12*


核心与内置
----------

* bpo-23722: The __class__ cell used by zero-argument super() is now
  initialized from type.__new__ rather than __build_class__, so class
  methods relying on that will now work correctly when called from
  metaclass methods during class creation. Patch by Martin Teichmann.

* bpo-25221: Fix corrupted result from PyLong_FromLong(0) when
  Python is compiled with NSMALLPOSINTS = 0.

* bpo-27080: Implement formatting support for **PEP 515**.  Initial
  patch by Chris Angelico.

* bpo-27199: In tarfile, expose copyfileobj bufsize to improve
  throughput. Patch by Jason Fried.

* bpo-27948: In f-strings, only allow backslashes inside the braces
  (where the expressions are).  This is a breaking change from the 3.6
  alpha releases, where backslashes are allowed anywhere in an
  f-string.  Also, require that expressions inside f-strings be
  enclosed within literal braces, and not escapes like
  "f'\x7b"hi"\x7d'".

* bpo-28046: Remove platform-specific directories from sys.path.

* bpo-28071: Add early-out for differencing from an empty set.

* bpo-25758: Prevents zipimport from unnecessarily encoding a
  filename (patch by Eryk Sun)

* bpo-25856: The __module__ attribute of extension classes and
  functions now is interned. This leads to more compact pickle data
  with protocol 4.

* bpo-27213: Rework CALL_FUNCTION* opcodes to produce shorter and
  more efficient bytecode. Patch by Demur Rumed, design by Serhiy
  Storchaka, reviewed by Serhiy Storchaka and Victor Stinner.

* bpo-26331: Implement tokenizing support for **PEP 515**. Patch by
  Georg Brandl.

* bpo-27999: Make "global after use" a SyntaxError, and ditto for
  nonlocal. Patch by Ivan Levkivskyi.

* bpo-28003: Implement **PEP 525** -- Asynchronous Generators.

* bpo-27985: Implement **PEP 526** -- Syntax for Variable
  Annotations. Patch by Ivan Levkivskyi.

* bpo-26058: Add a new private version to the builtin dict type,
  incremented at each dictionary creation and at each dictionary
  change. Implementation of the PEP 509.

* bpo-27364: A backslash-character pair that is not a valid escape
  sequence now generates a DeprecationWarning.  Patch by Emanuel
  Barry.

* bpo-27350: "dict" implementation is changed like PyPy. It is more
  compact and preserves insertion order. (Concept developed by Raymond
  Hettinger and patch by Inada Naoki.)

* bpo-27911: Remove unnecessary error checks in
  "exec_builtin_or_dynamic()".

* bpo-27078: Added BUILD_STRING opcode.  Optimized f-strings
  evaluation.

* bpo-17884: Python now requires systems with inttypes.h and
  stdint.h

* bpo-27961: Require platforms to support "long long". Python hasn't
  compiled without "long long" for years, so this is basically a
  formality.

* bpo-27355: Removed support for Windows CE.  It was never finished,
  and Windows CE is no longer a relevant platform for Python.

* Implement **PEP 523**.

* bpo-27870: A left shift of zero by a large integer no longer
  attempts to allocate large amounts of memory.

* bpo-25402: In int-to-decimal-string conversion, improve the
  estimate of the intermediate memory required, and remove an
  unnecessarily strict overflow check. Patch by Serhiy Storchaka.

* bpo-27214: In long_invert, be more careful about modifying object
  returned by long_add, and remove an unnecessary check for small
  longs. Thanks Oren Milman for analysis and patch.

* bpo-27506: Support passing the bytes/bytearray.translate()
  "delete" argument by keyword.

* bpo-27812: Properly clear out a generator's frame's backreference
  to the generator to prevent crashes in frame.clear().

* bpo-27811: Fix a crash when a coroutine that has not been awaited
  is finalized with warnings-as-errors enabled.

* bpo-27587: Fix another issue found by PVS-Studio: Null pointer
  check after use of 'def' in _PyState_AddModule(). Initial patch by
  Christian Heimes.

* bpo-27792: The modulo operation applied to "bool" and other "int"
  subclasses now always returns an "int". Previously the return type
  depended on the input values. Patch by Xiang Zhang.

* bpo-26984: int() now always returns an instance of exact int.

* bpo-25604: Fix a minor bug in integer true division; this bug
  could potentially have caused off-by-one-ulp results on platforms
  with unreliable ldexp implementations.

* bpo-24254: Make class definition namespace ordered by default.

* bpo-27662: Fix an overflow check in "List_New": the original code
  was checking against "Py_SIZE_MAX" instead of the correct upper
  bound of "Py_SSIZE_T_MAX". Patch by Xiang Zhang.

* bpo-27782: Multi-phase extension module import now correctly
  allows the "m_methods" field to be used to add module level
  functions to instances of non-module types returned from
  "Py_create_mod". Patch by Xiang Zhang.

* bpo-27936: The round() function accepted a second None argument
  for some types but not for others.  Fixed the inconsistency by
  accepting None for all numeric types.

* bpo-27487: Warn if a submodule argument to "python -m" or
  runpy.run_module() is found in sys.modules after parent packages are
  imported, but before the submodule is executed.

* bpo-27157: Make only type() itself accept the one-argument form.
  Patch by Eryk Sun and Emanuel Barry.

* bpo-27558: Fix a SystemError in the implementation of "raise"
  statement. In a brand new thread, raise a RuntimeError since there
  is no active exception to reraise. Patch written by Xiang Zhang.

* bpo-28008: Implement **PEP 530** -- asynchronous comprehensions.

* bpo-27942: Fix memory leak in codeobject.c


库
--

* bpo-28732: Fix crash in os.spawnv() with no elements in args

* bpo-28485: Always raise ValueError for negative
  compileall.compile_dir(workers=...) parameter, even when
  multithreading is unavailable.

* bpo-28037: Use sqlite3_get_autocommit() instead of setting
  Connection->inTransaction manually.

* bpo-25283: Attributes tm_gmtoff and tm_zone are now available on
  all platforms in the return values of time.localtime() and
  time.gmtime().

* bpo-24454: Regular expression match object groups are now
  accessible using __getitem__. "mo[x]" is equivalent to
  "mo.group(x)".

* bpo-10740: sqlite3 no longer implicitly commit an open transaction
  before DDL statements.

* bpo-17941: Add a *module* parameter to collections.namedtuple().

* bpo-22493: Inline flags now should be used only at the start of
  the regular expression. Deprecation warning is emitted if uses them
  in the middle of the regular expression.

* bpo-26885: xmlrpc now supports unmarshalling additional data types
  used by Apache XML-RPC implementation for numerics and None.

* bpo-28070: Fixed parsing inline verbose flag in regular
  expressions.

* bpo-19500: Add client-side SSL session resumption to the ssl
  module.

* bpo-28022: Deprecate ssl-related arguments in favor of SSLContext.
  The deprecation include manual creation of SSLSocket and
  certfile/keyfile (or similar) in ftplib, httplib, imaplib, smtplib,
  poplib and urllib.

* bpo-28043: SSLContext has improved default settings: OP_NO_SSLv2,
  OP_NO_SSLv3, OP_NO_COMPRESSION, OP_CIPHER_SERVER_PREFERENCE,
  OP_SINGLE_DH_USE, OP_SINGLE_ECDH_USE and HIGH ciphers without MD5.

* bpo-24693: Changed some RuntimeError's in the zipfile module to
  more appropriate types. Improved some error messages and debugging
  output.

* bpo-17909: "json.load" and "json.loads" now support binary input
  encoded as UTF-8, UTF-16 or UTF-32. Patch by Serhiy Storchaka.

* bpo-27137: the pure Python fallback implementation of
  "functools.partial" now matches the behaviour of its accelerated C
  counterpart for subclassing, pickling and text representation
  purposes. Patch by Emanuel Barry and Serhiy Storchaka.

* Fix possible integer overflows and crashes in the mmap module with
  unusual usage patterns.

* bpo-1703178: Fix the ability to pass the --link-objects option to
  the distutils build_ext command.

* bpo-28019: itertools.count() no longer rounds non-integer step in
  range between 1.0 and 2.0 to 1.

* bpo-18401: Pdb now supports the 'readrc' keyword argument to
  control whether .pdbrc files should be read.  Patch by Martin
  Matusiak and Sam Kimbrel.

* bpo-25969: Update the lib2to3 grammar to handle the unpacking
  generalizations added in 3.5.

* bpo-14977: mailcap now respects the order of the lines in the
  mailcap files ("first match"), as required by RFC 1542.  Patch by
  Michael Lazar.

* bpo-28082: Convert re flag constants to IntFlag.

* bpo-28025: Convert all ssl module constants to IntEnum and
  IntFlags. SSLContext properties now return flags and enums.

* bpo-23591: Add Flag, IntFlag, and auto() to enum module.

* bpo-433028: Added support of modifier spans in regular
  expressions.

* bpo-24594: Validates persist parameter when opening MSI database

* bpo-17582: xml.etree.ElementTree nows preserves whitespaces in
  attributes (Patch by Duane Griffin.  Reviewed and approved by Stefan
  Behnel.)

* bpo-28047: Fixed calculation of line length used for the base64
  CTE in the new email policies.

* bpo-27576: Fix call order in OrderedDict.__init__().

* email.generator.DecodedGenerator now supports the policy keyword.

* bpo-28027: Remove undocumented modules from "Lib/plat-*": IN,
  CDROM, DLFCN, TYPES, CDIO, and STROPTS.

* bpo-27445: Don't pass str(_charset) to MIMEText.set_payload().
  Patch by Claude Paroz.

* bpo-24277: The new email API is no longer provisional, and the
  docs have been reorganized and rewritten to emphasize the new API.

* bpo-22450: urllib now includes an "Accept: */*" header among the
  default headers. This makes the results of REST API requests more
  consistent and predictable especially when proxy servers are
  involved.

* lib2to3.pgen3.driver.load_grammar() now creates a stable cache
  file between runs given the same Grammar.txt input regardless of the
  hash randomization setting.

* bpo-28005: Allow ImportErrors in encoding implementation to
  propagate.

* bpo-26667: Support path-like objects in importlib.util.

* bpo-27570: Avoid zero-length memcpy() etc calls with null source
  pointers in the "ctypes" and "array" modules.

* bpo-22233: Break email header lines *only* on the RFC specified CR
  and LF characters, not on arbitrary unicode line breaks.  This also
  fixes a bug in HTTP header parsing.

* bpo-27331: The email.mime classes now all accept an optional
  policy keyword.

* bpo-27988: Fix email iter_attachments incorrect mutation of
  payload list.

* bpo-16113: Add SHA-3 and SHAKE support to hashlib module.

* Eliminate a tautological-pointer-compare warning in _scproxy.c.

* bpo-27776: The "os.urandom()" function does now block on Linux
  3.17 and newer until the system urandom entropy pool is initialized
  to increase the security. This change is part of the **PEP 524**.

* bpo-27778: Expose the Linux "getrandom()" syscall as a new
  "os.getrandom()" function. This change is part of the **PEP 524**.

* bpo-27691: Fix ssl module's parsing of GEN_RID subject alternative
  name fields in X.509 certs.

* bpo-18844: Add random.choices().

* bpo-25761: Improved error reporting about truncated pickle data in
  C implementation of unpickler.  UnpicklingError is now raised
  instead of AttributeError and ValueError in some cases.

* bpo-26798: Add BLAKE2 (blake2b and blake2s) to hashlib.

* bpo-26032: Optimized globbing in pathlib by using os.scandir(); it
  is now about 1.5--4 times faster.

* bpo-25596: Optimized glob() and iglob() functions in the glob
  module; they are now about 3--6 times faster.

* bpo-27928: Add scrypt (password-based key derivation function) to
  hashlib module (requires OpenSSL 1.1.0).

* bpo-27850: Remove 3DES from ssl module's default cipher list to
  counter measure sweet32 attack (CVE-2016-2183).

* bpo-27766: Add ChaCha20 Poly1305 to ssl module's default cipher
  list. (Required OpenSSL 1.1.0 or LibreSSL).

* bpo-25387: Check return value of winsound.MessageBeep.

* bpo-27866: Add SSLContext.get_ciphers() method to get a list of
  all enabled ciphers.

* bpo-27744: Add AF_ALG (Linux Kernel crypto) to socket module.

* bpo-26470: Port ssl and hashlib module to OpenSSL 1.1.0.

* bpo-11620: Fix support for SND_MEMORY in winsound.PlaySound.
  Based on a patch by Tim Lesher.

* bpo-11734: Add support for IEEE 754 half-precision floats to the
  struct module. Based on a patch by Eli Stevens.

* bpo-27919: Deprecated "extra_path" distribution option in
  distutils packaging.

* bpo-23229: Add new "cmath" constants: "cmath.inf" and "cmath.nan"
  to match "math.inf" and "math.nan", and also "cmath.infj" and
  "cmath.nanj" to match the format used by complex repr.

* bpo-27842: The csv.DictReader now returns rows of type
  OrderedDict. (Contributed by Steve Holden.)

* Remove support for passing a file descriptor to os.access. It
  never worked but previously didn't raise.

* bpo-12885: Fix error when distutils encounters symlink.

* bpo-27881: Fixed possible bugs when setting
  sqlite3.Connection.isolation_level. Based on patch by Xiang Zhang.

* bpo-27861: Fixed a crash in sqlite3.Connection.cursor() when a
  factory creates not a cursor.  Patch by Xiang Zhang.

* bpo-19884: Avoid spurious output on OS X with Gnu Readline.

* bpo-27706: Restore deterministic behavior of
  random.Random().seed() for string seeds using seeding version 1.
  Allows sequences of calls to random() to exactly match those
  obtained in Python 2. Patch by Nofar Schnider.

* bpo-10513: Fix a regression in Connection.commit().  Statements
  should not be reset after a commit.

* bpo-12319: Chunked transfer encoding support added to
  http.client.HTTPConnection requests.  The
  urllib.request.AbstractHTTPHandler class does not enforce a Content-
  Length header any more.  If a HTTP request has a file or iterable
  body, but no Content-Length header, the library now falls back to
  use chunked transfer-encoding.

* A new version of typing.py from https://github.com/python/typing:
  - Collection (only for 3.6) (bpo-27598) - Add FrozenSet to __all__
  (upstream #261) - fix crash in _get_type_vars() (upstream #259) -
  Remove the dict constraint in ForwardRef._eval_type (upstream #252)

* bpo-27832: Make "_normalize" parameter to "Fraction" constructor
  keyword-only, so that "Fraction(2, 3, 4)" now raises "TypeError".

* bpo-27539: Fix unnormalised "Fraction.__pow__" result in the case
  of negative exponent and negative base.

* bpo-21718: cursor.description is now available for queries using
  CTEs.

* bpo-27819: In distutils sdists, simply produce the "gztar"
  (gzipped tar format) distributions on all platforms unless "formats"
  is supplied.

* bpo-2466: posixpath.ismount now correctly recognizes mount points
  which the user does not have permission to access.

* bpo-9998: On Linux, ctypes.util.find_library now looks in
  LD_LIBRARY_PATH for shared libraries.

* bpo-27573: exit message for code.interact is now configurable.

* bpo-27930: Improved behaviour of logging.handlers.QueueListener.
  Thanks to Paulo Andrade and Petr Viktorin for the analysis and
  patch.

* bpo-6766: Distributed reference counting added to multiprocessing
  to support nesting of shared values / proxy objects.

* bpo-21201: Improves readability of multiprocessing error message.
  Thanks to Wojciech Walczak for patch.

* asyncio: 在各Transport类中添加了 set_protocol / get_protocol 方法

* bpo-27456: asyncio: Set TCP_NODELAY by default.


IDLE
----

* bpo-15308: Add 'interrupt execution' (^C) to Shell menu. Patch by
  Roger Serwy, updated by Bayard Randel.

* bpo-27922: Stop IDLE tests from 'flashing' gui widgets on the
  screen.

* bpo-27891: Consistently group and sort imports within idlelib
  modules.

* bpo-17642: add larger font sizes for classroom projection.

* 在 IDLE 帮助窗口的标题中加入版本号

* bpo-25564: In section on IDLE -- console differences, mention that
  using exec means that __builtins__ is defined for each statement.

* bpo-27821: Fix 3.6.0a3 regression that prevented custom key sets
  from being selected when no custom theme was defined.


C API
-----

* bpo-26900: Excluded underscored names and other private API from
  limited API.

* bpo-26027: Add support for path-like objects in
  PyUnicode_FSConverter() & PyUnicode_FSDecoder().


测试
----

* bpo-27427: Additional tests for the math module. Patch by
  Francisco Couzo.

* bpo-27953: Skip math and cmath tests that fail on OS X 10.4 due to
  a poor libm implementation of tan.

* bpo-26040: Improve test_math and test_cmath coverage and rigour.
  Patch by Jeff Allen.

* bpo-27787: Call gc.collect() before checking each test for
  "dangling threads", since the dangling threads are weak references.


构建
----

* bpo-27566: Fix clean target in freeze makefile (patch by Lisa
  Roach)

* bpo-27705: Update message in validate_ucrtbase.py

* bpo-27976: Deprecate building _ctypes with the bundled copy of
  libffi on non-OSX UNIX platforms.

* bpo-27983: Cause lack of llvm-profdata tool when using clang as
  required for PGO linking to be a configure time error rather than
  make time when "--with-optimizations" is enabled.  Also improve our
  ability to find the llvm-profdata tool on MacOS and some Linuxes.

* bpo-21590: Support for DTrace and SystemTap probes.

* bpo-26307: The profile-opt build now applies PGO to the built-in
  modules.

* bpo-26359: Add the --with-optimizations flag to turn on LTO and
  PGO build support when available.

* bpo-27917: Set platform triplets for Android builds.

* bpo-25825: Update references to the $(LIBPL) installation path on
  AIX. This path was changed in 3.2a4.

* 更新 OS X 安装包，使用SQLite 3.14.1 和 XZ 5.2.2版本。

* bpo-21122: Fix LTO builds on OS X.

* bpo-17128: Build OS X installer with a private copy of OpenSSL.
  Also provide a sample Install Certificates command script to install
  a set of root certificates from the third-party certifi module.


工具/示例
---------

* bpo-27952: Get Tools/scripts/fixcid.py working with Python 3 and
  the current "re" module, avoid invalid Python backslash escapes, and
  fix a bug parsing escaped C quote signs.


Windows
-------

* bpo-28065: Update xz dependency to 5.2.2 and build it from source.

* bpo-25144: Ensures TargetDir is set before continuing with custom
  install.

* bpo-1602: Windows console doesn't input or print Unicode (PEP 528)

* bpo-27781: Change file system encoding on Windows to UTF-8 (PEP
  529)

* bpo-27731: Opt-out of MAX_PATH on Windows 10

* bpo-6135: Adds encoding and errors parameters to subprocess.

* bpo-27959: Adds oem encoding, alias ansi to mbcs, move aliasmbcs
  to codec lookup.

* bpo-27982: The functions of the winsound module now accept keyword
  arguments.

* bpo-20366: Build full text search support into SQLite on Windows.

* bpo-27756: Adds new icons for Python files and processes on
  Windows. Designs by Cherry Wang.

* bpo-27883: Update sqlite to 3.14.1.0 on Windows.


Python 3.6.0 alpha 4
====================

*Release date: 2016-08-15*


核心与内置
----------

* bpo-27704: Optimized creating bytes and bytearray from byte-like
  objects and iterables. Speed up to 3 times for short objects.
  Original patch by Naoki Inada.

* bpo-26823: Large sections of repeated lines in tracebacks are now
  abbreviated as "[Previous line repeated {count} more times]" by the
  builtin traceback rendering. Patch by Emanuel Barry.

* bpo-27574: Decreased an overhead of parsing keyword arguments in
  functions implemented with using Argument Clinic.

* bpo-22557: Now importing already imported modules is up to 2.5
  times faster.

* bpo-17596: Include <wincrypt.h> to help with Min GW building.

* bpo-17599: On Windows, rename the privately defined
  REPARSE_DATA_BUFFER structure to avoid conflicting with the
  definition from Min GW.

* bpo-27507: Add integer overflow check in bytearray.extend().
  Patch by Xiang Zhang.

* bpo-27581: Don't rely on wrapping for overflow check in
  PySequence_Tuple().  Patch by Xiang Zhang.

* bpo-1621: Avoid signed integer overflow in list and tuple
  operations. Patch by Xiang Zhang.

* bpo-27419: Standard __import__() no longer look up "__import__" in
  globals or builtins for importing submodules or "from import". Fixed
  a crash if raise a warning about unabling to resolve package from
  __spec__ or __package__.

* bpo-27083: Respect the PYTHONCASEOK environment variable under
  Windows.

* bpo-27514: Make having too many statically nested blocks a
  SyntaxError instead of SystemError.

* bpo-27366: Implemented **PEP 487** (Simpler customization of class
  creation). Upon subclassing, the __init_subclass__ classmethod is
  called on the base class. Descriptors are initialized with
  __set_name__ after class creation.


库
--

* bpo-26027: Add **PEP 519**/__fspath__() support to the os and
  os.path modules. Includes code from Jelle Zijlstra. (See also:
  bpo-27524)

* bpo-27598: Add Collections to collections.abc. Patch by Ivan
  Levkivskyi, docs by Neil Girdhar.

* bpo-25958: Support "anti-registration" of special methods from
  various ABCs, like __hash__, __iter__ or __len__.  All these (and
  several more) can be set to None in an implementation class and the
  behavior will be as if the method is not defined at all.
  (Previously, this mechanism existed only for __hash__, to make
  mutable classes unhashable.)  Code contributed by Andrew Barnert and
  Ivan Levkivskyi.

* bpo-16764: Support keyword arguments to zlib.decompress().  Patch
  by Xiang Zhang.

* bpo-27736: Prevent segfault after interpreter re-initialization
  due to ref count problem introduced in code for bpo-27038 in
  3.6.0a3. Patch by Xiang Zhang.

* bpo-25628: The *verbose* and *rename* parameters for
  collections.namedtuple are now keyword-only.

* bpo-12345: Add mathematical constant tau to math and cmath. See
  also **PEP 628**.

* bpo-26823: traceback.StackSummary.format now abbreviates large
  sections of repeated lines as "[Previous line repeated {count} more
  times]" (this change then further affects other traceback display
  operations in the module). Patch by Emanuel Barry.

* bpo-27664: Add to concurrent.futures.thread.ThreadPoolExecutor()
  the ability to specify a thread name prefix.

* bpo-27181: Add geometric_mean and harmonic_mean to statistics
  module.

* bpo-27573: code.interact now prints an message when exiting.

* bpo-6422: Add autorange method to timeit.Timer objects.

* bpo-27773: Correct some memory management errors server_hostname
  in _ssl.wrap_socket().

* bpo-26750: unittest.mock.create_autospec() now works properly for
  subclasses of property() and other data descriptors.  Removes the
  never publicly used, never documented unittest.mock.DescriptorTypes
  tuple.

* bpo-26754: Undocumented support of general bytes-like objects as
  path in compile() and similar functions is now deprecated.

* bpo-26800: Undocumented support of general bytes-like objects as
  paths in os functions is now deprecated.

* bpo-26981: Add _order_ compatibility shim to enum.Enum for Python
  2/3 code bases.

* bpo-27661: Added tzinfo keyword argument to datetime.combine.

* In the curses module, raise an error if window.getstr() or
  window.instr() is passed a negative value.

* bpo-27783: Fix possible usage of uninitialized memory in
  operator.methodcaller.

* bpo-27774: Fix possible Py_DECREF on unowned object in _sre.

* bpo-27760: Fix possible integer overflow in binascii.b2a_qp.

* bpo-27758: Fix possible integer overflow in the _csv module for
  large record lengths.

* bpo-27568: Prevent HTTPoxy attack (CVE-2016-1000110). Ignore the
  HTTP_PROXY variable when REQUEST_METHOD environment is set, which
  indicates that the script is in CGI mode.

* bpo-7063: Remove dead code from the "array" module's slice
  handling. Patch by Chuck.

* bpo-27656: Do not assume sched.h defines any SCHED_* constants.

* bpo-27130: In the "zlib" module, fix handling of large buffers
  (typically 4 GiB) when compressing and decompressing.  Previously,
  inputs were limited to 4 GiB, and compression and decompression
  operations did not properly handle results of 4 GiB.

* bpo-24773: Implemented **PEP 495** (Local Time Disambiguation).

* Expose the EPOLLEXCLUSIVE constant (when it is defined) in the
  select module.

* bpo-27567: Expose the EPOLLRDHUP and POLLRDHUP constants in the
  select module.

* bpo-1621: Avoid signed int negation overflow in the "audioop"
  module.

* bpo-27533: Release GIL in nt._isdir

* bpo-17711: Fixed unpickling by the persistent ID with protocol 0.
  Original patch by Alexandre Vassalotti.

* bpo-27522: Avoid an unintentional reference cycle in
  email.feedparser.

* bpo-27512: Fix a segfault when os.fspath() called an __fspath__()
  method that raised an exception. Patch by Xiang Zhang.


IDLE
----

* bpo-27714: text_textview and test_autocomplete now pass when re-
  run in the same process.  This occurs when test_idle fails when run
  with the -w option but without -jn.  Fix warning from test_config.

* bpo-27621: Put query response validation error messages in the
  query box itself instead of in a separate messagebox.  Redo tests to
  match. Add Mac OSX refinements. Original patch by Mark Roseman.

* bpo-27620: Escape key now closes Query box as cancelled.

* bpo-27609: IDLE: tab after initial whitespace should tab, not
  autocomplete. This fixes problem with writing docstrings at least
  twice indented.

* bpo-27609: Explicitly return None when there are also non-None
  returns. In a few cases, reverse a condition and eliminate a return.

* bpo-25507: IDLE no longer runs buggy code because of its tkinter
  imports. Users must include the same imports required to run
  directly in Python.

* bpo-27173: Add 'IDLE Modern Unix' to the built-in key sets. Make
  the default key set depend on the platform. Add tests for the
  changes to the config module.

* bpo-27452: add line counter and crc to IDLE configHandler test
  dump.


测试
----

* bpo-25805: Skip a test in test_pkgutil as needed that doesn't work
  when "__name__ == __main__". Patch by SilentGhost.

* bpo-27472: Add test.support.unix_shell as the path to the default
  shell.

* bpo-27369: In test_pyexpat, avoid testing an error message detail
  that changed in Expat 2.2.0.

* bpo-27594: Prevent assertion error when running test_ast with
  coverage enabled: ensure code object has a valid first line number.
  Patch suggested by Ivan Levkivskyi.


Windows
-------

* bpo-27647: Update bundled Tcl/Tk to 8.6.6.

* bpo-27610: Adds **PEP 514** metadata to Windows installer

* bpo-27469: Adds a shell extension to the launcher so that drag and
  drop works correctly.

* bpo-27309: Enables proper Windows styles in python[w].exe
  manifest.


构建
----

* bpo-27713: Suppress spurious build warnings when updating
  importlib's bootstrap files. Patch by Xiang Zhang

* bpo-25825: Correct the references to Modules/python.exp, which is
  required on AIX.  The references were accidentally changed in
  3.5.0a1.

* bpo-27453: CPP invocation in configure must use CPPFLAGS. Patch by
  Chi Hsuan Yen.

* bpo-27641: The configure script now inserts comments into the
  makefile to prevent the pgen and _freeze_importlib executables from
  being cross-compiled.

* bpo-26662: Set PYTHON_FOR_GEN in configure as the Python program
  to be used for file generation during the build.

* bpo-10910: Avoid C++ compilation errors on FreeBSD and OS X. Also
  update FreedBSD version checks for the original ctype UTF-8
  workaround.


Python 3.6.0 alpha 3
====================

*Release date: 2016-07-11*


核心与内置
----------

* bpo-27473: Fixed possible integer overflow in bytes and bytearray
  concatenations. Patch by Xiang Zhang.

* bpo-23034: The output of a special Python build with defined
  COUNT_ALLOCS, SHOW_ALLOC_COUNT or SHOW_TRACK_COUNT macros is now off
  by  default.  It can be re-enabled using the "-X showalloccount"
  option.  It now outputs to stderr instead of stdout.

* bpo-27443: __length_hint__() of bytearray iterators no longer
  return a negative integer for a resized bytearray.

* bpo-27007: The fromhex() class methods of bytes and bytearray
  subclasses now return an instance of corresponding subclass.


库
--

* bpo-26844: Fix error message for imp.find_module() to refer to
  'path' instead of 'name'. Patch by Lev Maximov.

* bpo-23804: Fix SSL zero-length recv() calls to not block and not
  raise an error about unclean EOF.

* bpo-27466: Change time format returned by
  http.cookie.time2netscape, confirming the netscape cookie format and
  making it consistent with documentation.

* bpo-21708: Deprecated dbm.dumb behavior that differs from common
  dbm behavior: creating a database in 'r' and 'w' modes and modifying
  a database in 'r' mode.

* bpo-26721: Change the socketserver.StreamRequestHandler.wfile
  attribute to implement BufferedIOBase. In particular, the write()
  method no longer does partial writes.

* bpo-22115: Added methods trace_add, trace_remove and trace_info in
  the tkinter.Variable class.  They replace old methods
  trace_variable, trace, trace_vdelete and trace_vinfo that use
  obsolete Tcl commands and might not work in future versions of Tcl.
  Fixed old tracing methods: trace_vdelete() with wrong mode no longer
  break tracing, trace_vinfo() now always returns a list of pairs of
  strings, tracing in the "u" mode now works.

* bpo-26243: Only the level argument to zlib.compress() is keyword
  argument now.  The first argument is positional-only.

* bpo-27038: Expose the DirEntry type as os.DirEntry. Code patch by
  Jelle Zijlstra.

* bpo-27186: Update os.fspath()/PyOS_FSPath() to check the return
  value of __fspath__() to be either str or bytes.

* bpo-18726: All optional parameters of the dump(), dumps(), load()
  and loads() functions and JSONEncoder and JSONDecoder class
  constructors in the json module are now keyword-only.

* bpo-27319: Methods selection_set(), selection_add(),
  selection_remove() and selection_toggle() of ttk.TreeView now allow
  passing multiple items as multiple arguments instead of passing them
  as a tuple.  Deprecated undocumented ability of calling the
  selection() method with arguments.

* bpo-27079: Fixed curses.ascii functions isblank(), iscntrl() and
  ispunct().

* bpo-27294: Numerical state in the repr for Tkinter event objects
  is now represented as a combination of known flags.

* bpo-27177: Match objects in the re module now support index-like
  objects as group indices.  Based on patches by Jeroen Demeyer and
  Xiang Zhang.

* bpo-26754: Some functions (compile() etc) accepted a filename
  argument encoded as an iterable of integers. Now only strings and
  byte-like objects are accepted.

* bpo-26536: socket.ioctl now supports SIO_LOOPBACK_FAST_PATH. Patch
  by Daniel Stokes.

* bpo-27048: Prevents distutils failing on Windows when environment
  variables contain non-ASCII characters

* bpo-27330: Fixed possible leaks in the ctypes module.

* bpo-27238: Got rid of bare excepts in the turtle module.  Original
  patch by Jelle Zijlstra.

* bpo-27122: When an exception is raised within the context being
  managed by a contextlib.ExitStack() and one of the exit stack
  generators catches and raises it in a chain, do not re-raise the
  original exception when exiting, let the new chained one through.
  This avoids the **PEP 479** bug described in issue25782.


安全
----

* bpo-27278: Fix os.urandom() implementation using getrandom() on
  Linux. Truncate size to INT_MAX and loop until we collected enough
  random bytes, instead of casting a directly Py_ssize_t to int.


库
--

* bpo-16864: sqlite3.Cursor.lastrowid now supports REPLACE
  statement. Initial patch by Alex LordThorsen.

* bpo-26386: Fixed ttk.TreeView selection operations with item id's
  containing spaces.

* bpo-8637: Honor a pager set by the env var MANPAGER (in preference
  to one set by the env var PAGER).


安全
----

* bpo-22636: Avoid shell injection problems with
  ctypes.util.find_library().


库
--

* bpo-16182: Fix various functions in the "readline" module to use
  the locale encoding, and fix get_begidx() and get_endidx() to return
  code point indexes.

* bpo-27392: Add loop.connect_accepted_socket(). Patch by Jim
  Fulton.


IDLE
----

* bpo-27477: IDLE search dialogs now use ttk widgets.

* bpo-27173: Add 'IDLE Modern Unix' to the built-in key sets. Make
  the default key set depend on the platform. Add tests for the
  changes to the config module.

* bpo-27452: make command line "idle-test> python test_help.py"
  work. __file__ is relative when python is started in the file's
  directory.

* bpo-27452: add line counter and crc to IDLE configHandler test
  dump.

* bpo-27380: IDLE: add query.py with base Query dialog and ttk
  widgets. Module had subclasses SectionName, ModuleName, and
  HelpSource, which are used to get information from users by
  configdialog and file =>Load Module. Each subclass has itw own
  validity checks.  Using ModuleName allows users to edit bad module
  names instead of starting over. Add tests and delete the two files
  combined into the new one.

* bpo-27372: Test_idle no longer changes the locale.

* bpo-27365: Allow non-ascii chars in IDLE NEWS.txt, for contributor
  names.

* bpo-27245: IDLE: Cleanly delete custom themes and key bindings.
  Previously, when IDLE was started from a console or by import, a
  cascade of warnings was emitted. Patch by Serhiy Storchaka.

* bpo-24137: Run IDLE, test_idle, and htest with tkinter default
  root disabled.  Fix code and tests that fail with this restriction.
  Fix htests to not create a second and redundant root and mainloop.

* bpo-27310: Fix IDLE.app failure to launch on OS X due to vestigial
  import.


C API
-----

* bpo-26754: PyUnicode_FSDecoder() accepted a filename argument
  encoded as an iterable of integers. Now only strings and byte-like
  objects are accepted.


构建
----

* bpo-28066: Fix the logic that searches build directories for
  generated include files when building outside the source tree.

* bpo-27442: Expose the Android API level that python was built
  against, in sysconfig.get_config_vars() as 'ANDROID_API_LEVEL'.

* bpo-27434: The interpreter that runs the cross-build, found in
  PATH, must now be of the same feature version (e.g. 3.6) as the
  source being built.

* bpo-26930: Update Windows builds to use OpenSSL 1.0.2h.

* bpo-23968: Rename the platform directory from plat-$(MACHDEP) to
  plat-$(PLATFORM_TRIPLET). Rename the config directory (LIBPL) from
  config-$(LDVERSION) to config-$(LDVERSION)-$(PLATFORM_TRIPLET).
  Install the platform specific _sysconfigdata module into the
  platform directory and rename it to include the ABIFLAGS.

* 在 GNU/Hurd 系统中不使用大文件支持。


工具/示例
---------

* bpo-27332: Fixed the type of the first argument of module-level
  functions generated by Argument Clinic.  Patch by Petr Viktorin.

* bpo-27418: Fixed Tools/importbench/importbench.py.


文档
----

* bpo-19489: Moved the search box from the sidebar to the header and
  footer of each page. Patch by Ammar Askar.

* bpo-27285: Update documentation to reflect the deprecation of
  "pyvenv" and normalize on the term "virtual environment". Patch by
  Steve Piercy.


测试
----

* bpo-27027: Added test.support.is_android that is True when this is
  an Android build.


Python 3.6.0 alpha 2
====================

*Release date: 2016-06-13*


核心与内置
----------

* bpo-27095: Simplified MAKE_FUNCTION and removed MAKE_CLOSURE
  opcodes. Patch by Demur Rumed.

* bpo-27190: Raise NotSupportedError if sqlite3 is older than 3.3.1.
  Patch by Dave Sawyer.

* bpo-27286: Fixed compiling BUILD_MAP_UNPACK_WITH_CALL opcode.
  Calling function with generalized unpacking (PEP 448) and
  conflicting keyword names could cause undefined behavior.

* bpo-27140: Added BUILD_CONST_KEY_MAP opcode.

* bpo-27186: Add support for os.PathLike objects to open() (part of
  **PEP 519**).

* bpo-27066: Fixed SystemError if a custom opener (for open())
  returns a negative number without setting an exception.

* bpo-26983: float() now always return an instance of exact float.
  The deprecation warning is emitted if __float__ returns an instance
  of a strict subclass of float.  In a future versions of Python this
  can be an error.

* bpo-27097: Python interpreter is now about 7% faster due to
  optimized instruction decoding.  Based on patch by Demur Rumed.

* bpo-26647: Python interpreter now uses 16-bit wordcode instead of
  bytecode. Patch by Demur Rumed.

* bpo-23275: Allow assigning to an empty target list in round
  brackets: () = iterable.

* bpo-27243: Update the __aiter__ protocol: instead of returning an
  awaitable that resolves to an asynchronous iterator, the
  asynchronous iterator should be returned directly.  Doing the former
  will trigger a PendingDeprecationWarning.


库
--

* Comment out socket (SO_REUSEPORT) and posix (O_SHLOCK, O_EXLOCK)
  constants exposed on the API which are not implemented on GNU/Hurd.
  They would not work at runtime anyway.

* bpo-27025: Generated names for Tkinter widgets are now more
  meaningful and recognizable.

* bpo-25455: Fixed crashes in repr of recursive ElementTree.Element
  and functools.partial objects.

* bpo-27294: Improved repr for Tkinter event objects.

* bpo-20508: Improve exception message of
  IPv{4,6}Network.__getitem__. Patch by Gareth Rees.


安全
----

* bpo-26556: Update expat to 2.1.1, fixes CVE-2015-1283.

* Fix TLS stripping vulnerability in smtplib, CVE-2016-0772.
  Reported by Team Oststrom.


库
--

* bpo-21386: Implement missing IPv4Address.is_global property.  It
  was documented since 07a5610bae9d.  Initial patch by Roger Luethi.

* bpo-27029: Removed deprecated support of universal newlines mode
  from ZipFile.open().

* bpo-27030: Unknown escapes consisting of "'\'" and an ASCII letter
  in regular expressions now are errors.  The re.LOCALE flag now can
  be used only with bytes patterns.

* bpo-27186: Add os.PathLike support to DirEntry (part of **PEP
  519**). Initial patch by Jelle Zijlstra.

* bpo-20900: distutils register command now decodes HTTP responses
  correctly.  Initial patch by ingrid.

* bpo-27186: Add os.PathLike support to pathlib, removing its
  provisional status (part of PEP 519). Initial patch by Dusty
  Phillips.

* bpo-27186: Add support for os.PathLike objects to os.fsencode()
  and os.fsdecode() (part of **PEP 519**).

* bpo-27186: Introduce os.PathLike and os.fspath() (part of **PEP
  519**).

* A new version of typing.py provides several new classes and
  features: @overload outside stubs, Reversible, DefaultDict, Text,
  ContextManager, Type[], NewType(), TYPE_CHECKING, and numerous bug
  fixes (note that some of the new features are not yet implemented in
  mypy or other static analyzers). Also classes for **PEP 492**
  (Awaitable, AsyncIterable, AsyncIterator) have been added (in fact
  they made it into 3.5.1 but were never mentioned).

* bpo-25738: Stop http.server.BaseHTTPRequestHandler.send_error()
  from sending a message body for 205 Reset Content.  Also, don't send
  Content header fields in responses that don't have a body.  Patch by
  Susumu Koshiba.

* bpo-21313: Fix the "platform" module to tolerate when sys.version
  contains truncated build information.


安全
----

* bpo-26839: On Linux, "os.urandom()" now calls "getrandom()" with
  "GRND_NONBLOCK" to fall back on reading "/dev/urandom" if the
  urandom entropy pool is not initialized yet. Patch written by Colm
  Buckley.


库
--

* bpo-23883: Added missing APIs to __all__ to match the documented
  APIs for the following modules: cgi, mailbox, mimetypes, plistlib
  and smtpd. Patches by Jacek Kołodziej.

* bpo-27164: In the zlib module, allow decompressing raw Deflate
  streams with a predefined zdict.  Based on patch by Xiang Zhang.

* bpo-24291: Fix wsgiref.simple_server.WSGIRequestHandler to
  completely write data to the client.  Previously it could do partial
  writes and truncate data.  Also, wsgiref.handler.ServerHandler can
  now handle stdout doing partial writes, but this is deprecated.

* bpo-21272: Use _sysconfigdata.py to initialize
  distutils.sysconfig.

* bpo-19611: "inspect" now reports the implicit ".0" parameters
  generated by the compiler for comprehension and generator expression
  scopes as if they were positional-only parameters called
  "implicit0". Patch by Jelle Zijlstra.

* bpo-26809: Add "__all__" to "string".  Patch by Emanuel Barry.

* bpo-26373: subprocess.Popen.communicate now correctly ignores
  BrokenPipeError when the child process dies before .communicate() is
  called in more/all circumstances.

* signal, socket, and ssl module IntEnum constant name lookups now
  return a consistent name for values having multiple names.  Ex:
  signal.Signals(6) now refers to itself as signal.SIGALRM rather than
  flipping between that and signal.SIGIOT based on the interpreter's
  hash randomization seed.

* bpo-27167: Clarify the subprocess.CalledProcessError error message
  text when the child process died due to a signal.

* bpo-25931: Don't define socketserver.Forking* names on platforms
  such as Windows that do not support os.fork().

* bpo-21776: distutils.upload now correctly handles HTTPError.
  Initial patch by Claudiu Popa.

* bpo-26526: Replace custom parse tree validation in the parser
  module with a simple DFA validator.

* bpo-27114: Fix SSLContext._load_windows_store_certs fails with
  PermissionError

* bpo-18383: Avoid creating duplicate filters when using
  filterwarnings and simplefilter. Based on patch by Alex Shkop.

* bpo-23026: winreg.QueryValueEx() now return an integer for
  REG_QWORD type.

* bpo-26741: subprocess.Popen destructor now emits a ResourceWarning
  warning if the child process is still running.

* bpo-27056: Optimize pickle.load() and pickle.loads(), up to 10%
  faster to deserialize a lot of small objects.

* bpo-21271: New keyword only parameters in reset_mock call.


IDLE
----

* bpo-5124: Paste with text selected now replaces the selection on
  X11. This matches how paste works on Windows, Mac, most modern Linux
  apps, and ttk widgets. Original patch by Serhiy Storchaka.

* bpo-24750: Switch all scrollbars in IDLE to ttk versions. Where
  needed, minimal tests are added to cover changes.

* bpo-24759: IDLE requires tk 8.5 and availability ttk widgets.
  Delete now unneeded tk version tests and code for older versions.
  Add test for IDLE syntax colorizer.

* bpo-27239: idlelib.macosx.isXyzTk functions initialize as needed.

* bpo-27262: move Aqua unbinding code, which enable context menus,
  to macosx.

* bpo-24759: Make clear in idlelib.idle_test.__init__ that the
  directory is a private implementation of test.test_idle and tool for
  maintainers.

* bpo-27196: Stop 'ThemeChanged' warnings when running IDLE tests.
  These persisted after other warnings were suppressed in #20567.
  Apply Serhiy Storchaka's update_idletasks solution to four test
  files. Record this additional advice in idle_test/README.txt

* bpo-20567: Revise idle_test/README.txt with advice about avoiding
  tk warning messages from tests.  Apply advice to several IDLE tests.

* bpo-24225: Update idlelib/README.txt with new file names and event
  handlers.

* bpo-27156: Remove obsolete code not used by IDLE.

* bpo-27117: Make colorizer htest and turtledemo work with dark
  themes. Move code for configuring text widget colors to a new
  function.

* bpo-24225: Rename many "idlelib/*.py" and "idle_test/test_*.py"
  files. Edit files to replace old names with new names when the old
  name referred to the module rather than the class it contained. See
  the issue and IDLE section in What's New in 3.6 for more.

* bpo-26673: When tk reports font size as 0, change to size 10. Such
  fonts on Linux prevented the configuration dialog from opening.

* bpo-21939: Add test for IDLE's percolator. Original patch by
  Saimadhav Heblikar.

* bpo-21676: Add test for IDLE's replace dialog. Original patch by
  Saimadhav Heblikar.

* bpo-18410: Add test for IDLE's search dialog. Original patch by
  Westley Martínez.

* bpo-21703: Add test for undo delegator.  Patch mostly by Saimadhav
  Heblikar .

* bpo-27044: Add ConfigDialog.remove_var_callbacks to stop memory
  leaks.

* bpo-23977: Add more asserts to test_delegator.


文档
----

* bpo-16484: Change the default PYTHONDOCS URL to "https:", and fix
  the resulting links to use lowercase.  Patch by Sean Rodman, test by
  Kaushik Nadikuditi.

* bpo-24136: Document the new **PEP 448** unpacking syntax of 3.5.

* bpo-22558: Add remaining doc links to source code for Python-coded
  modules. Patch by Yoni Lavi.


测试
----

* bpo-25285: regrtest now uses subprocesses when the -j1 command
  line option is used: each test file runs in a fresh child process.
  Before, the -j1 option was ignored.

* bpo-25285: Tools/buildbot/test.bat script now uses -j1 by default
  to run each test file in fresh child process.


Windows
-------

* bpo-27064: The py.exe launcher now defaults to Python 3. The
  Windows launcher "py.exe" no longer prefers an installed Python 2
  version over Python 3 by default when used interactively.


构建
----

* bpo-27229: Fix the cross-compiling pgen rule for in-tree builds.
  Patch by Xavier de Gaye.

* bpo-26930: Update OS X 10.5+ 32-bit-only installer to build and
  link with OpenSSL 1.0.2h.


Windows
-------

* bpo-17500: Remove unused and outdated icons. (See also:
  https://github.com/python/pythondotorg/issues/945)


C API
-----

* bpo-27186: Add the PyOS_FSPath() function (part of **PEP 519**).

* bpo-26282: PyArg_ParseTupleAndKeywords() now supports positional-
  only parameters.


工具/示例
---------

* bpo-26282: Argument Clinic now supports positional-only and
  keyword parameters in the same function.


Python 3.6.0 alpha 1
====================

*Release date: 2016-05-16*


核心与内置
----------

* bpo-20041: Fixed TypeError when frame.f_trace is set to None.
  Patch by Xavier de Gaye.

* bpo-26168: Fixed possible refleaks in failing Py_BuildValue() with
  the "N" format unit.

* bpo-26991: Fix possible refleak when creating a function with
  annotations.

* bpo-27039: Fixed bytearray.remove() for values greater than 127.
  Based on patch by Joe Jevnik.

* bpo-23640: int.from_bytes() no longer bypasses constructors for
  subclasses.

* bpo-27005: Optimized the float.fromhex() class method for exact
  float. It is now 2 times faster.

* bpo-18531: Single var-keyword argument of dict subtype was passed
  unscathed to the C-defined function.  Now it is converted to exact
  dict.

* bpo-26811: gc.get_objects() no longer contains a broken tuple with
  NULL pointer.

* bpo-20120: Use RawConfigParser for .pypirc parsing, removing
  support for interpolation unintentionally added with move to Python
  3. Behavior no longer does any interpolation in .pypirc files,
  matching behavior in Python 2.7 and Setuptools 19.0.

* bpo-26249: Memory functions of the "PyMem_Malloc()" domain
  ("PYMEM_DOMAIN_MEM") now use the pymalloc allocator rather than
  system "malloc()". Applications calling "PyMem_Malloc()" without
  holding the GIL can now crash: use "PYTHONMALLOC=debug" environment
  variable to validate the usage of memory allocators in your
  application.

* bpo-26802: Optimize function calls only using unpacking like
  "func(*tuple)" (no other positional argument, no keyword): avoid
  copying the tuple. Patch written by Joe Jevnik.

* bpo-26659: Make the builtin slice type support cycle collection.

* bpo-26718: super.__init__ no longer leaks memory if called
  multiple times. NOTE: A direct call of super.__init__ is not
  endorsed!

* bpo-27138: Fix the doc comment for FileFinder.find_spec().

* bpo-27147: Mention **PEP 420** in the importlib docs.

* bpo-25339: PYTHONIOENCODING now has priority over locale in
  setting the error handler for stdin and stdout.

* bpo-26494: Fixed crash on iterating exhausting iterators. Affected
  classes are generic sequence iterators, iterators of str, bytes,
  bytearray, list, tuple, set, frozenset, dict, OrderedDict,
  corresponding views and os.scandir() iterator.

* bpo-26574: Optimize "bytes.replace(b'', b'.')" and
  "bytearray.replace(b'', b'.')". Patch written by Josh Snider.

* bpo-26581: If coding cookie is specified multiple times on a line
  in Python source code file, only the first one is taken to account.

* bpo-19711: Add tests for reloading namespace packages.

* bpo-21099: Switch applicable importlib tests to use **PEP 451**
  API.

* bpo-26563: Debug hooks on Python memory allocators now raise a
  fatal error if functions of the "PyMem_Malloc()" family are called
  without holding the GIL.

* bpo-26564: On error, the debug hooks on Python memory allocators
  now use the "tracemalloc" module to get the traceback where a memory
  block was allocated.

* bpo-26558: The debug hooks on Python memory allocator
  "PyObject_Malloc()" now detect when functions are called without
  holding the GIL.

* bpo-26516: Add "PYTHONMALLOC" environment variable to set the
  Python memory allocators and/or install debug hooks.

* bpo-26516: The "PyMem_SetupDebugHooks()" function can now also be
  used on Python compiled in release mode.

* bpo-26516: The "PYTHONMALLOCSTATS" environment variable can now
  also be used on Python compiled in release mode. It now has no
  effect if set to an empty string.

* bpo-26516: In debug mode, debug hooks are now also installed on
  Python memory allocators when Python is configured without pymalloc.

* bpo-26464: Fix str.translate() when string is ASCII and first
  replacements removes character, but next replacement uses a non-
  ASCII character or a string longer than 1 character. Regression
  introduced in Python 3.5.0.

* bpo-22836: Ensure exception reports from PyErr_Display() and
  PyErr_WriteUnraisable() are sensible even when formatting them
  produces secondary errors.  This affects the reports produced by
  sys.__excepthook__() and when __del__() raises an exception.

* bpo-26302: Correct behavior to reject comma as a legal character
  for cookie names.

* bpo-26136: Upgrade the warning when a generator raises
  StopIteration from PendingDeprecationWarning to DeprecationWarning.
  Patch by Anish Shah.

* bpo-26204: The compiler now ignores all constant statements:
  bytes, str, int, float, complex, name constants (None, False, True),
  Ellipsis and ast.Constant; not only str and int. For example, "1.0"
  is now ignored in "def f(): 1.0".

* bpo-4806: Avoid masking the original TypeError exception when
  using star ("*") unpacking in function calls.  Based on patch by
  Hagen Fürstenau and Daniel Urban.

* bpo-26146: Add a new kind of AST node: "ast.Constant". It can be
  used by external AST optimizers, but the compiler does not emit
  directly such node.

* bpo-23601: Sped-up allocation of dict key objects by using
  Python's small object allocator.  (Contributed by Julian Taylor.)

* bpo-18018: Import raises ImportError instead of SystemError if a
  relative import is attempted without a known parent package.

* bpo-25843: When compiling code, don't merge constants if they are
  equal but have a different types. For example, "f1, f2 = lambda: 1,
  lambda: 1.0" is now correctly compiled to two different functions:
  "f1()" returns "1" ("int") and "f2()" returns "1.0" ("float"), even
  if "1" and "1.0" are equal.

* bpo-26107: The format of the "co_lnotab" attribute of code objects
  changes to support negative line number delta.

* bpo-26154: Add a new private _PyThreadState_UncheckedGet()
  function to get the current Python thread state, but don't issue a
  fatal error if it is NULL. This new function must be used instead of
  accessing directly the _PyThreadState_Current variable.  The
  variable is no more exposed since Python 3.5.1 to hide the exact
  implementation of atomic C types, to avoid compiler issues.

* bpo-25791: If __package__ != __spec__.parent or if neither
  __package__ or __spec__ are defined then ImportWarning is raised.

* bpo-22995: [UPDATE] Comment out the one of the pickleability tests
  in _PyObject_GetState() due to regressions observed in Cython-based
  projects.

* bpo-25961: Disallowed null characters in the type name.

* bpo-25973: Fix segfault when an invalid nonlocal statement binds a
  name starting with two underscores.

* bpo-22995: Instances of extension types with a state that aren't
  subclasses of list or dict and haven't implemented any pickle-
  related methods (__reduce__, __reduce_ex__, __getnewargs__,
  __getnewargs_ex__, or __getstate__), can no longer be pickled.
  Including memoryview.

* bpo-20440: Massive replacing unsafe attribute setting code with
  special macro Py_SETREF.

* bpo-25766: Special method __bytes__() now works in str subclasses.

* bpo-25421: __sizeof__ methods of builtin types now use dynamic
  basic size. This allows sys.getsize() to work correctly with their
  subclasses with __slots__ defined.

* bpo-25709: Fixed problem with in-place string concatenation and
  utf-8 cache.

* bpo-5319: New Py_FinalizeEx() API allowing Python to set an exit
  status of 120 on failure to flush buffered streams.

* bpo-25485: telnetlib.Telnet is now a context manager.

* bpo-24097: Fixed crash in object.__reduce__() if slot name is
  freed inside __getattr__.

* bpo-24731: Fixed crash on converting objects with special methods
  __bytes__, __trunc__, and __float__ returning instances of
  subclasses of bytes, int, and float to subclasses of bytes, int, and
  float correspondingly.

* bpo-25630: Fix a possible segfault during argument parsing in
  functions that accept filesystem paths.

* bpo-23564: Fixed a partially broken sanity check in the
  _posixsubprocess internals regarding how fds_to_pass were passed to
  the child.  The bug had no actual impact as subprocess.py already
  avoided it.

* bpo-25388: Fixed tokenizer crash when processing undecodable
  source code with a null byte.

* bpo-25462: The hash of the key now is calculated only once in most
  operations in C implementation of OrderedDict.

* bpo-22995: Default implementation of __reduce__ and __reduce_ex__
  now rejects builtin types with not defined __new__.

* bpo-24802: Avoid buffer overreads when int(), float(), compile(),
  exec() and eval() are passed bytes-like objects.  These objects are
  not necessarily terminated by a null byte, but the functions assumed
  they were.

* bpo-25555: Fix parser and AST: fill lineno and col_offset of "arg"
  node when compiling AST from Python objects.

* bpo-24726: Fixed a crash and leaking NULL in repr() of OrderedDict
  that was mutated by direct calls of dict methods.

* bpo-25449: Iterating OrderedDict with keys with unstable hash now
  raises KeyError in C implementations as well as in Python
  implementation.

* bpo-25395: Fixed crash when highly nested OrderedDict structures
  were garbage collected.

* bpo-25401: Optimize bytes.fromhex() and bytearray.fromhex(): they
  are now between 2x and 3.5x faster.

* bpo-25399: Optimize bytearray % args using the new private
  _PyBytesWriter API. Formatting is now between 2.5 and 5 times
  faster.

* bpo-25274: sys.setrecursionlimit() now raises a RecursionError if
  the new recursion limit is too low depending at the current
  recursion depth. Modify also the "lower-water mark" formula to make
  it monotonic. This mark is used to decide when the overflowed flag
  of the thread state is reset.

* bpo-24402: Fix input() to prompt to the redirected stdout when
  sys.stdout.fileno() fails.

* bpo-25349: Optimize bytes % args using the new private
  _PyBytesWriter API. Formatting is now up to 2 times faster.

* bpo-24806: Prevent builtin types that are not allowed to be
  subclassed from being subclassed through multiple inheritance.

* bpo-25301: The UTF-8 decoder is now up to 15 times as fast for
  error handlers: "ignore", "replace" and "surrogateescape".

* bpo-24848: Fixed a number of bugs in UTF-7 decoding of misformed
  data.

* bpo-25267: The UTF-8 encoder is now up to 75 times as fast for
  error handlers: "ignore", "replace", "surrogateescape",
  "surrogatepass". Patch co-written with Serhiy Storchaka.

* bpo-25280: Import trace messages emitted in verbose (-v) mode are
  no longer formatted twice.

* bpo-25227: Optimize ASCII and latin1 encoders with the
  "surrogateescape" error handler: the encoders are now up to 3 times
  as fast. Initial patch written by Serhiy Storchaka.

* bpo-25003: On Solaris 11.3 or newer, os.urandom() now uses the
  getrandom() function instead of the getentropy() function. The
  getentropy() function is blocking to generate very good quality
  entropy, os.urandom() doesn't need such high-quality entropy.

* bpo-9232: Modify Python's grammar to allow trailing commas in the
  argument list of a function declaration.  For example, "def f(*, a =
  3,): pass" is now legal. Patch from Mark Dickinson.

* bpo-24965: Implement **PEP 498** "Literal String Interpolation".
  This allows you to embed expressions inside f-strings, which are
  converted to normal strings at run time. Given x=3, then
  f'value={x}' == 'value=3'. Patch by Eric V. Smith.

* bpo-26478: Fix semantic bugs when using binary operators with
  dictionary views and tuples.

* bpo-26171: Fix possible integer overflow and heap corruption in
  zipimporter.get_data().

* bpo-25660: Fix TAB key behaviour in REPL with readline.

* bpo-26288: Optimize PyLong_AsDouble.

* bpo-26289: Optimize floor and modulo division for single-digit
  longs. Microbenchmarks show 2-2.5x improvement.  Built-in 'divmod'
  function is now also ~10% faster. (See also: bpo-26315)

* bpo-25887: Raise a RuntimeError when a coroutine object is awaited
  more than once.


库
--

* bpo-27057: Fix os.set_inheritable() on Android, ioctl() is blocked
  by SELinux and fails with EACCESS. The function now falls back to
  fcntl(). Patch written by Michał Bednarski.

* bpo-27014: Fix infinite recursion using typing.py.  Thanks to
  Kalle Tuure!

* bpo-27031: Removed dummy methods in Tkinter widget classes:
  tk_menuBar() and tk_bindForTraversal().

* bpo-14132: Fix urllib.request redirect handling when the target
  only has a query string.  Original fix by Ján Janech.

* bpo-17214: The "urllib.request" module now percent-encodes non-
  ASCII bytes found in redirect target URLs.  Some servers send
  Location header fields with non-ASCII bytes, but "http.client"
  requires the request target to be ASCII-encodable, otherwise a
  UnicodeEncodeError is raised.  Based on patch by Christian Heimes.

* bpo-27033: The default value of the decode_data parameter for
  smtpd.SMTPChannel and smtpd.SMTPServer constructors is changed to
  False.

* bpo-27034: Removed deprecated class asynchat.fifo.

* bpo-26870: Added readline.set_auto_history(), which can stop
  entries being automatically added to the history list.  Based on
  patch by Tyler Crompton.

* bpo-26039: zipfile.ZipFile.open() can now be used to write data
  into a ZIP file, as well as for extracting data.  Patch by Thomas
  Kluyver.

* bpo-26892: Honor debuglevel flag in urllib.request.HTTPHandler.
  Patch contributed by Chi Hsuan Yen.

* bpo-22274: In the subprocess module, allow stderr to be redirected
  to stdout even when stdout is not redirected.  Patch by Akira Li.

* bpo-26807: mock_open 'files' no longer error on readline at end of
  file. Patch from Yolanda Robla.

* bpo-25745: Fixed leaking a userptr in curses panel destructor.

* bpo-26977: Removed unnecessary, and ignored, call to sum of
  squares helper in statistics.pvariance.

* bpo-26002: Use bisect in statistics.median instead of a linear
  search. Patch by Upendra Kuma.

* bpo-25974: Make use of new Decimal.as_integer_ratio() method in
  statistics module. Patch by Stefan Krah.

* bpo-26996: Add secrets module as described in **PEP 506**.

* bpo-26881: The modulefinder module now supports extended opcode
  arguments.

* bpo-23815: Fixed crashes related to directly created instances of
  types in _tkinter and curses.panel modules.

* bpo-17765: weakref.ref() no longer silently ignores keyword
  arguments. Patch by Georg Brandl.

* bpo-26873: xmlrpc now raises ResponseError on unsupported type
  tags instead of silently return incorrect result.

* bpo-26915: The __contains__ methods in the collections ABCs now
  check for identity before checking equality.  This better matches
  the behavior of the concrete classes, allows sensible handling of
  NaNs, and makes it easier to reason about container invariants.

* bpo-26711: Fixed the comparison of plistlib.Data with other types.

* bpo-24114: Fix an uninitialized variable in "ctypes.util". The bug
  only occurs on SunOS when the ctypes implementation searches for the
  "crle" program.  Patch by Xiang Zhang.  Tested on SunOS by Kees Bos.

* bpo-26864: In urllib.request, change the proxy bypass host
  checking against no_proxy to be case-insensitive, and to not match
  unrelated host names that happen to have a bypassed hostname as a
  suffix. Patch by Xiang Zhang.

* bpo-24902: Print server URL on http.server startup.  Initial patch
  by Felix Kaiser.

* bpo-25788: fileinput.hook_encoded() now supports an "errors"
  argument for passing to open.  Original patch by Joseph Hackman.

* bpo-26634: recursive_repr() now sets __qualname__ of wrapper.
  Patch by Xiang Zhang.

* bpo-26804: urllib.request will prefer lower_case proxy environment
  variables over UPPER_CASE or Mixed_Case ones. Patch contributed by
  Hans-Peter Jansen.

* bpo-26837: assertSequenceEqual() now correctly outputs non-
  stringified differing items (like bytes in the -b mode).  This
  affects assertListEqual() and assertTupleEqual().

* bpo-26041: Remove "will be removed in Python 3.7" from deprecation
  messages of platform.dist() and platform.linux_distribution(). Patch
  by Kumaripaba Miyurusara Athukorala.

* bpo-26822: itemgetter, attrgetter and methodcaller objects no
  longer silently ignore keyword arguments.

* bpo-26733: Disassembling a class now disassembles class and static
  methods. Patch by Xiang Zhang.

* bpo-26801: Fix error handling in "shutil.get_terminal_size()",
  catch "AttributeError" instead of "NameError". Patch written by
  Emanuel Barry.

* bpo-24838: tarfile's ustar and gnu formats now correctly calculate
  name and link field limits for multibyte character encodings like
  utf-8.


安全
----

* bpo-26657: Fix directory traversal vulnerability with http.server
  on Windows.  This fixes a regression that was introduced in 3.3.4rc1
  and 3.4.0rc1.  Based on patch by Philipp Hagemeister.


库
--

* bpo-26717: Stop encoding Latin-1-ized WSGI paths with UTF-8.
  Patch by Anthony Sottile.

* bpo-26782: Add STARTUPINFO to subprocess.__all__ on Windows.

* bpo-26404: Add context manager to socketserver.  Patch by Aviv
  Palivoda.

* bpo-26735: Fix "os.urandom()" on Solaris 11.3 and newer when
  reading more than 1,024 bytes: call "getrandom()" multiple times
  with a limit of 1024 bytes per call.

* bpo-26585: Eliminate http.server._quote_html() and use
  html.escape(quote=False).  Patch by Xiang Zhang.

* bpo-26685: Raise OSError if closing a socket fails.

* bpo-16329: Add .webm to mimetypes.types_map.  Patch by Giampaolo
  Rodola'.

* bpo-13952: Add .csv to mimetypes.types_map.  Patch by Geoff
  Wilson.

* bpo-26587: the site module now allows .pth files to specify files
  to be added to sys.path (e.g. zip files).

* bpo-25609: Introduce contextlib.AbstractContextManager and
  typing.ContextManager.

* bpo-26709: Fixed Y2038 problem in loading binary PLists.

* bpo-23735: Handle terminal resizing with Readline 6.3+ by
  installing our own SIGWINCH handler.  Patch by Eric Price.

* bpo-25951: Change SSLSocket.sendall() to return None, as
  explicitly documented for plain socket objects.  Patch by Aviv
  Palivoda.

* bpo-26586: In http.server, respond with "413 Request header fields
  too large" if there are too many header fields to parse, rather than
  killing the connection and raising an unhandled exception.  Patch by
  Xiang Zhang.

* bpo-26676: Added missing XMLPullParser to ElementTree.__all__.

* bpo-22854: Change BufferedReader.writable() and
  BufferedWriter.readable() to always return False.

* bpo-26492: Exhausted iterator of array.array now conforms with the
  behavior of iterators of other mutable sequences: it lefts exhausted
  even if iterated array is extended.

* bpo-26641: doctest.DocFileTest and doctest.testfile() now support
  packages (module splitted into multiple directories) for the package
  parameter.

* bpo-25195: Fix a regression in mock.MagicMock. _Call is a subclass
  of tuple (changeset 3603bae63c13 only works for classes) so we need
  to implement __ne__ ourselves.  Patch by Andrew Plummer.

* bpo-26644: Raise ValueError rather than SystemError when a
  negative length is passed to SSLSocket.recv() or read().

* bpo-23804: Fix SSL recv(0) and read(0) methods to return zero
  bytes instead of up to 1024.

* bpo-26616: Fixed a bug in datetime.astimezone() method.

* bpo-26637: The "importlib" module now emits an "ImportError"
  rather than a "TypeError" if "__import__()" is tried during the
  Python shutdown process but "sys.path" is already cleared (set to
  "None").

* bpo-21925: "warnings.formatwarning()" now catches exceptions when
  calling "linecache.getline()" and
  "tracemalloc.get_object_traceback()" to be able to log
  "ResourceWarning" emitted late during the Python shutdown process.

* bpo-23848: On Windows, faulthandler.enable() now also installs an
  exception handler to dump the traceback of all Python threads on any
  Windows exception, not only on UNIX signals (SIGSEGV, SIGFPE,
  SIGABRT).

* bpo-26530: Add C functions "_PyTraceMalloc_Track()" and
  "_PyTraceMalloc_Untrack()" to track memory blocks using the
  "tracemalloc" module. Add "_PyTraceMalloc_GetTraceback()" to get the
  traceback of an object.

* bpo-26588: The _tracemalloc now supports tracing memory
  allocations of multiple address spaces (domains).

* bpo-24266: Ctrl+C during Readline history search now cancels the
  search mode when compiled with Readline 7.

* bpo-26590: Implement a safe finalizer for the _socket.socket type.
  It now releases the GIL to close the socket.

* bpo-18787: spwd.getspnam() now raises a PermissionError if the
  user doesn't have privileges.

* bpo-26560: Avoid potential ValueError in
  BaseHandler.start_response. Initial patch by Peter Inglesby.

* bpo-26567: Add a new function "PyErr_ResourceWarning()" function
  to pass the destroyed object. Add a *source* attribute to
  "warnings.WarningMessage". Add warnings._showwarnmsg() which uses
  tracemalloc to get the traceback where source object was allocated.


安全
----

* bpo-26313: ssl.py _load_windows_store_certs fails if windows cert
  store is empty. Patch by Baji.


库
--

* bpo-26569: Fix "pyclbr.readmodule()" and "pyclbr.readmodule_ex()"
  to support importing packages.

* bpo-26499: Account for remaining Content-Length in
  HTTPResponse.readline() and read1(). Based on patch by Silent Ghost.
  Also document that HTTPResponse now supports these methods.

* bpo-25320: Handle sockets in directories unittest discovery is
  scanning. Patch from Victor van den Elzen.

* bpo-16181: cookiejar.http2time() now returns None if year is
  higher than datetime.MAXYEAR.

* bpo-26513: Fixes platform module detection of Windows Server

* bpo-23718: Fixed parsing time in week 0 before Jan 1.  Original
  patch by Tamás Bence Gedai.

* bpo-26323: Add Mock.assert_called() and Mock.assert_called_once()
  methods to unittest.mock. Patch written by Amit Saha.

* bpo-20589: Invoking Path.owner() and Path.group() on Windows now
  raise NotImplementedError instead of ImportError.

* bpo-26177: Fixed the keys() method for Canvas and Scrollbar
  widgets.

* bpo-15068: Got rid of excessive buffering in fileinput. The
  bufsize parameter is now deprecated and ignored.

* bpo-19475: Added an optional argument timespec to the datetime
  isoformat() method to choose the precision of the time component.

* bpo-2202: Fix UnboundLocalError in
  AbstractDigestAuthHandler.get_algorithm_impls. Initial patch by
  Mathieu Dupuy.

* bpo-26167: Minimized overhead in copy.copy() and copy.deepcopy().
  Optimized copying and deepcopying bytearrays, NotImplemented,
  slices, short lists, tuples, dicts, sets.

* bpo-25718: Fixed pickling and copying the accumulate() iterator
  with total is None.

* bpo-26475: Fixed debugging output for regular expressions with the
  (?x) flag.

* bpo-26482: Allowed pickling recursive dequeues.

* bpo-26335: Make mmap.write() return the number of bytes written
  like other write methods.  Patch by Jakub Stasiak.

* bpo-26457: Fixed the subnets() methods in IP network classes for
  the case when resulting prefix length is equal to maximal prefix
  length. Based on patch by Xiang Zhang.

* bpo-26385: Remove the file if the internal open() call in
  NamedTemporaryFile() fails. Patch by Silent Ghost.

* bpo-26402: Fix XML-RPC client to retry when the server shuts down
  a persistent connection.  This was a regression related to the new
  http.client.RemoteDisconnected exception in 3.5.0a4.

* bpo-25913: Leading "<~" is optional now in base64.a85decode() with
  adobe=True.  Patch by Swati Jaiswal.

* bpo-26186: Remove an invalid type check in
  importlib.util.LazyLoader.

* bpo-26367: importlib.__import__() raises ImportError like
  builtins.__import__() when "level" is specified but without an
  accompanying package specified.

* bpo-26309: In the "socketserver" module, shut down the request
  (closing the connected socket) when verify_request() returns false.
  Patch by Aviv Palivoda.

* bpo-23430: Change the socketserver module to only catch exceptions
  raised from a request handler that are derived from Exception
  (instead of BaseException). Therefore SystemExit and
  KeyboardInterrupt no longer trigger the handle_error() method, and
  will now to stop a single-threaded server.


安全
----

* bpo-25939: On Windows open the cert store readonly in
  ssl.enum_certificates.


库
--

* bpo-25995: os.walk() no longer uses FDs proportional to the tree
  depth.

* bpo-25994: Added the close() method and the support of the context
  manager protocol for the os.scandir() iterator.

* bpo-23992: multiprocessing: make MapResult not fail-fast upon
  exception.

* bpo-26243: Support keyword arguments to zlib.compress().  Patch by
  Aviv Palivoda.

* bpo-26117: The os.scandir() iterator now closes file descriptor
  not only when the iteration is finished, but when it was failed with
  error.

* bpo-25949: __dict__ for an OrderedDict instance is now created
  only when needed.

* bpo-25911: Restored support of bytes paths in os.walk() on
  Windows.

* bpo-26045: Add UTF-8 suggestion to error message when posting a
  non- Latin-1 string with http.client.

* bpo-26039: Added zipfile.ZipInfo.from_file() and
  zipinfo.ZipInfo.is_dir(). Patch by Thomas Kluyver.

* bpo-12923: Reset FancyURLopener's redirect counter even if there
  is an exception. Based on patches by Brian Brazil and Daniel Rocco.

* bpo-25945: Fixed a crash when unpickle the functools.partial
  object with wrong state. Fixed a leak in failed functools.partial
  constructor. "args" and "keywords" attributes of functools.partial
  have now always types tuple and dict correspondingly.

* bpo-26202: copy.deepcopy() now correctly copies range() objects
  with non-atomic attributes.

* bpo-23076: Path.glob() now raises a ValueError if it's called with
  an invalid pattern. Patch by Thomas Nyberg.

* bpo-19883: Fixed possible integer overflows in zipimport.

* bpo-26227: On Windows, getnameinfo(), gethostbyaddr() and
  gethostbyname_ex() functions of the socket module now decode the
  hostname from the ANSI code page rather than UTF-8.

* bpo-26099: The site module now writes an error into stderr if
  sitecustomize module can be imported but executing the module raise
  an ImportError. Same change for usercustomize.

* bpo-26147: xmlrpc now works with strings not encodable with used
  non-UTF-8 encoding.

* bpo-25935: Garbage collector now breaks reference loops with
  OrderedDict.

* bpo-16620: Fixed AttributeError in msilib.Directory.glob().

* bpo-26013: Added compatibility with broken protocol 2 pickles
  created in old Python 3 versions (3.4.3 and lower).

* bpo-26129: Deprecated accepting non-integers in grp.getgrgid().

* bpo-25850: Use cross-compilation by default for 64-bit Windows.

* bpo-25822: Add docstrings to the fields of urllib.parse results.
  Patch contributed by Swati Jaiswal.

* bpo-22642: Convert trace module option parsing mechanism to
  argparse. Patch contributed by SilentGhost.

* bpo-24705: Fix sysconfig._parse_makefile not expanding ${} vars
  appearing before $() vars.

* bpo-26069: Remove the deprecated apis in the trace module.

* bpo-22138: Fix mock.patch behavior when patching descriptors.
  Restore original values after patching. Patch contributed by Sean
  McCully.

* bpo-25672: In the ssl module, enable the SSL_MODE_RELEASE_BUFFERS
  mode option if it is safe to do so.

* bpo-26012: Don't traverse into symlinks for "**" pattern in
  pathlib.Path.[r]glob().

* bpo-24120: Ignore PermissionError when traversing a tree with
  pathlib.Path.[r]glob(). Patch by Ulrich Petri.

* bpo-21815: Accept ] characters in the data portion of imap
  responses, in order to handle the flags with square brackets
  accepted and produced by servers such as gmail.

* bpo-25447: fileinput now uses sys.stdin as-is if it does not have
  a buffer attribute (restores backward compatibility).

* bpo-25971: Optimized creating Fractions from floats by 2 times and
  from Decimals by 3 times.

* bpo-25802: Document as deprecated the remaining implementations of
  importlib.abc.Loader.load_module().

* bpo-25928: Add Decimal.as_integer_ratio().

* bpo-25447: Copying the lru_cache() wrapper object now always
  works, independently from the type of the wrapped object (by
  returning the original object unchanged).

* bpo-25768: Have the functions in compileall return booleans
  instead of ints and add proper documentation and tests for the
  return values.

* bpo-24103: Fixed possible use after free in
  ElementTree.XMLPullParser.

* bpo-25860: os.fwalk() no longer skips remaining directories when
  error occurs. Original patch by Samson Lee.

* bpo-25914: Fixed and simplified OrderedDict.__sizeof__.

* bpo-25869: Optimized deepcopying ElementTree; it is now 20 times
  faster.

* bpo-25873: Optimized iterating ElementTree.  Iterating elements
  Element.iter() is now 40% faster, iterating text Element.itertext()
  is now up to 2.5 times faster.

* bpo-25902: Fixed various refcount issues in ElementTree iteration.

* bpo-22227: The TarFile iterator is reimplemented using generator.
  This implementation is simpler that using class.

* bpo-25638: Optimized ElementTree.iterparse(); it is now 2x faster.
  Optimized ElementTree parsing; it is now 10% faster.

* bpo-25761: Improved detecting errors in broken pickle data.

* bpo-25717: Restore the previous behaviour of tolerating most
  fstat() errors when opening files.  This was a regression in 3.5a1,
  and stopped anonymous temporary files from working in special cases.

* bpo-24903: Fix regression in number of arguments compileall
  accepts when '-d' is specified.  The check on the number of
  arguments has been dropped completely as it never worked correctly
  anyway.

* bpo-25764: In the subprocess module, preserve any exception caused
  by fork() failure when preexec_fn is used.

* bpo-25771: Tweak the exception message for
  importlib.util.resolve_name() when 'package' isn't specified but
  necessary.

* bpo-6478: _strptime's regexp cache now is reset after changing
  timezone with time.tzset().

* bpo-14285: When executing a package with the "python -m package"
  option, and package initialization fails, a proper traceback is now
  reported.  The "runpy" module now lets exceptions from package
  initialization pass back to the caller, rather than raising
  ImportError.

* bpo-19771: Also in runpy and the "-m" option, omit the irrelevant
  message ". . . is a package and cannot be directly executed" if the
  package could not even be initialized (e.g. due to a bad "*.pyc"
  file).

* bpo-25177: Fixed problem with the mean of very small and very
  large numbers. As a side effect, statistics.mean and
  statistics.variance should be significantly faster.

* bpo-25718: Fixed copying object with state with boolean value is
  false.

* bpo-10131: Fixed deep copying of minidom documents.  Based on
  patch by Marian Ganisin.

* bpo-7990: dir() on ElementTree.Element now lists properties:
  "tag", "text", "tail" and "attrib".  Original patch by Santoso
  Wijaya.

* bpo-25725: Fixed a reference leak in pickle.loads() when
  unpickling invalid data including tuple instructions.

* bpo-25663: In the Readline completer, avoid listing duplicate
  global names, and search the global namespace before searching
  builtins.

* bpo-25688: Fixed file leak in ElementTree.iterparse() raising an
  error.

* bpo-23914: Fixed SystemError raised by unpickler on broken pickle
  data.

* bpo-25691: Fixed crash on deleting ElementTree.Element attributes.

* bpo-25624: ZipFile now always writes a ZIP_STORED header for
  directory entries.  Patch by Dingyuan Wang.

* bpo-25626: Change three zlib functions to accept sizes that fit in
  Py_ssize_t, but internally cap those sizes to UINT_MAX.  This
  resolves a regression in 3.5 where GzipFile.read() failed to read
  chunks larger than 2 or 4 GiB.  The change affects the
  zlib.Decompress.decompress() max_length parameter, the
  zlib.decompress() bufsize parameter, and the zlib.Decompress.flush()
  length parameter.

* bpo-25583: Avoid incorrect errors raised by
  os.makedirs(exist_ok=True) when the OS gives priority to errors such
  as EACCES over EEXIST.

* bpo-25593: Change semantics of EventLoop.stop() in asyncio.

* bpo-6973: When we know a subprocess.Popen process has died, do not
  allow the send_signal(), terminate(), or kill() methods to do
  anything as they could potentially signal a different process.

* bpo-23883: Added missing APIs to __all__ to match the documented
  APIs for the following modules: calendar, csv, enum, fileinput,
  ftplib, logging, optparse, tarfile, threading and wave.  Also added
  a test.support.check__all__() helper. Patches by Jacek Kołodziej,
  Mauro S. M. Rodrigues and Joel Taddei.

* bpo-25590: In the Readline completer, only call getattr() once per
  attribute.  Also complete names of attributes such as properties and
  slots which are listed by dir() but not yet created on an instance.

* bpo-25498: Fix a crash when garbage-collecting ctypes objects
  created by wrapping a memoryview.  This was a regression made in
  3.5a1.  Based on patch by Eryksun.

* bpo-25584: Added "escape" to the __all__ list in the glob module.

* bpo-25584: Fixed recursive glob() with patterns starting with
  "**".

* bpo-25446: Fix regression in smtplib's AUTH LOGIN support.

* bpo-18010: Fix the pydoc web server's module search function to
  handle exceptions from importing packages.

* bpo-25554: Got rid of circular references in regular expression
  parsing.

* bpo-18973: Command-line interface of the calendar module now uses
  argparse instead of optparse.

* bpo-25510: fileinput.FileInput.readline() now returns b'' instead
  of '' at the end if the FileInput was opened with binary mode. Patch
  by Ryosuke Ito.

* bpo-25503: Fixed inspect.getdoc() for inherited docstrings of
  properties. Original patch by John Mark Vandenberg.

* bpo-25515: Always use os.urandom as a source of randomness in
  uuid.uuid4.

* bpo-21827: Fixed textwrap.dedent() for the case when largest
  common whitespace is a substring of smallest leading whitespace.
  Based on patch by Robert Li.

* bpo-25447: The lru_cache() wrapper objects now can be copied and
  pickled (by returning the original object unchanged).

* bpo-25390: typing: Don't crash on Union[str, Pattern].

* bpo-25441: asyncio: Raise error from drain() when socket is
  closed.

* bpo-25410: Cleaned up and fixed minor bugs in C implementation of
  OrderedDict.

* bpo-25411: Improved Unicode support in SMTPHandler through better
  use of the email package. Thanks to user simon04 for the patch.

* Move the imp module from a PendingDeprecationWarning to
  DeprecationWarning.

* bpo-25407: Remove mentions of the formatter module being removed
  in Python 3.6.

* bpo-25406: Fixed a bug in C implementation of
  OrderedDict.move_to_end() that caused segmentation fault or hang in
  iterating after moving several items to the start of ordered dict.

* bpo-25382: pickletools.dis() now outputs implicit memo index for
  the MEMOIZE opcode.

* bpo-25357: Add an optional newline parameter to
  binascii.b2a_base64(). base64.b64encode() uses it to avoid a memory
  copy.

* bpo-24164: Objects that need calling "__new__" with keyword
  arguments, can now be pickled using pickle protocols older than
  protocol version 4.

* bpo-25364: zipfile now works in threads disabled builds.

* bpo-25328: smtpd's SMTPChannel now correctly raises a ValueError
  if both decode_data and enable_SMTPUTF8 are set to true.

* bpo-16099: RobotFileParser now supports Crawl-delay and Request-
  rate extensions.  Patch by Nikolay Bogoychev.

* bpo-25316: distutils raises OSError instead of
  DistutilsPlatformError when MSVC is not installed.

* bpo-25380: Fixed protocol for the STACK_GLOBAL opcode in
  pickletools.opcodes.

* bpo-23972: Updates asyncio datagram create method allowing
  reuseport and reuseaddr socket options to be set prior to binding
  the socket. Mirroring the existing asyncio create_server method the
  reuseaddr option for datagram sockets defaults to True if the O/S is
  'posix' (except if the platform is Cygwin). Patch by Chris Laws.

* bpo-25304: Add asyncio.run_coroutine_threadsafe().  This lets you
  submit a coroutine to a loop from another thread, returning a
  concurrent.futures.Future.  By Vincent Michel.

* bpo-25232: Fix CGIRequestHandler to split the query from the URL
  at the first question mark (?) rather than the last. Patch from
  Xiang Zhang.

* bpo-24657: Prevent CGIRequestHandler from collapsing slashes in
  the query part of the URL as if it were a path. Patch from Xiang
  Zhang.

* bpo-25287: Don't add crypt.METHOD_CRYPT to crypt.methods if it's
  not supported. Check if it is supported, it may not be supported on
  OpenBSD for example.

* bpo-23600: Default implementation of tzinfo.fromutc() was
  returning wrong results in some cases.

* bpo-25203: Failed readline.set_completer_delims() no longer left
  the module in inconsistent state.

* bpo-25011: rlcompleter now omits private and special attribute
  names unless the prefix starts with underscores.

* bpo-25209: rlcompleter now can add a space or a colon after
  completed keyword.

* bpo-22241: timezone.utc name is now plain 'UTC', not 'UTC-00:00'.

* bpo-23517: fromtimestamp() and utcfromtimestamp() methods of
  datetime.datetime now round microseconds to nearest with ties going
  to nearest even integer (ROUND_HALF_EVEN), as round(float), instead
  of rounding towards -Infinity (ROUND_FLOOR).

* bpo-23552: Timeit now warns when there is substantial (4x)
  variance between best and worst times. Patch from Serhiy Storchaka.

* bpo-24633: site-packages/README -> README.txt.

* bpo-24879: help() and pydoc can now list named tuple fields in the
  order they were defined rather than alphabetically.  The ordering is
  determined by the _fields attribute if present.

* bpo-24874: Improve speed of itertools.cycle() and make its pickle
  more compact.

* Fix crash in itertools.cycle.__setstate__() when the first
  argument wasn't a list.

* bpo-20059: urllib.parse raises ValueError on all invalid ports.
  Patch by Martin Panter.

* bpo-24360: Improve __repr__ of argparse.Namespace() for invalid
  identifiers.  Patch by Matthias Bussonnier.

* bpo-23426: run_setup was broken in distutils. Patch from Alexander
  Belopolsky.

* bpo-13938: 2to3 converts StringTypes to a tuple. Patch from Mark
  Hammond.

* bpo-2091: open() accepted a 'U' mode string containing '+', but
  'U' can only be used with 'r'. Patch from Jeff Balogh and John
  O'Connor.

* bpo-8585: improved tests for zipimporter2. Patch from Mark
  Lawrence.

* bpo-18622: unittest.mock.mock_open().reset_mock would recurse
  infinitely. Patch from Nicola Palumbo and Laurent De Buyst.

* bpo-24426: Fast searching optimization in regular expressions now
  works for patterns that starts with capturing groups.  Fast
  searching optimization now can't be disabled at compile time.

* bpo-23661: unittest.mock side_effects can now be exceptions again.
  This was a regression vs Python 3.4. Patch from Ignacio Rossi

* bpo-13248: Remove deprecated inspect.getmoduleinfo function.

* bpo-25578: Fix (another) memory leak in SSLSocket.getpeercer().

* bpo-25530: Disable the vulnerable SSLv3 protocol by default when
  creating ssl.SSLContext.

* bpo-25569: Fix memory leak in SSLSocket.getpeercert().

* bpo-25471: Sockets returned from accept() shouldn't appear to be
  nonblocking.

* bpo-25319: When threading.Event is reinitialized, the underlying
  condition should use a regular lock rather than a recursive lock.

* Skip getaddrinfo if host is already resolved. Patch by A. Jesse
  Jiryu Davis.

* bpo-26050: Add asyncio.StreamReader.readuntil() method. Patch by
  Марк Коренберг.

* bpo-25924: Avoid unnecessary serialization of getaddrinfo(3) calls
  on OS X versions 10.5 or higher.  Original patch by A. Jesse Jiryu
  Davis.

* bpo-26406: Avoid unnecessary serialization of getaddrinfo(3) calls
  on current versions of OpenBSD and NetBSD.  Patch by A. Jesse Jiryu
  Davis.

* bpo-26848: Fix asyncio/subprocess.communicate() to handle empty
  input. Patch by Jack O'Connor.

* bpo-27040: Add loop.get_exception_handler method

* bpo-27041: asyncio: Add loop.create_future method


IDLE
----

* bpo-20640: Add tests for idlelib.configHelpSourceEdit. Patch by
  Saimadhav Heblikar.

* In the 'IDLE-console differences' section of the IDLE doc, clarify
  how running with IDLE affects sys.modules and the standard streams.

* bpo-25507: fix incorrect change in IOBinding that prevented
  printing. Augment IOBinding htest to include all major IOBinding
  functions.

* bpo-25905: Revert unwanted conversion of ' to ’ RIGHT SINGLE
  QUOTATION MARK in README.txt and open this and NEWS.txt with
  'ascii'. Re-encode CREDITS.txt to utf-8 and open it with 'utf-8'.

* bpo-15348: Stop the debugger engine (normally in a user process)
  before closing the debugger window (running in the IDLE process).
  This prevents the RuntimeErrors that were being caught and ignored.

* bpo-24455: Prevent IDLE from hanging when a) closing the shell
  while the debugger is active (15347); b) closing the debugger with
  the [X] button (15348); and c) activating the debugger when already
  active (24455). The patch by Mark Roseman does this by making two
  changes. 1. Suspend and resume the gui.interaction method with the
  tcl vwait mechanism intended for this purpose (instead of
  root.mainloop & .quit). 2. In gui.run, allow any existing
  interaction to terminate first.

* Change 'The program' to 'Your program' in an IDLE 'kill program?'
  message to make it clearer that the program referred to is the
  currently running user program, not IDLE itself.

* bpo-24750: Improve the appearance of the IDLE editor window status
  bar. Patch by Mark Roseman.

* bpo-25313: Change the handling of new built-in text color themes
  to better address the compatibility problem introduced by the
  addition of IDLE Dark. Consistently use the revised
  idleConf.CurrentTheme everywhere in idlelib.

* bpo-24782: Extension configuration is now a tab in the IDLE
  Preferences dialog rather than a separate dialog.  The former tabs
  are now a sorted list.  Patch by Mark Roseman.

* bpo-22726: Re-activate the config dialog help button with some
  content about the other buttons and the new IDLE Dark theme.

* bpo-24820: IDLE now has an 'IDLE Dark' built-in text color theme.
  It is more or less IDLE Classic inverted, with a cobalt blue
  background. Strings, comments, keywords, ... are still green, red,
  orange, ... . To use it with IDLEs released before November 2015,
  hit the 'Save as New Custom Theme' button and enter a new name, such
  as 'Custom Dark'.  The custom theme will work with any IDLE release,
  and can be modified.

* bpo-25224: README.txt is now an idlelib index for IDLE developers
  and curious users. The previous user content is now in the IDLE doc
  chapter. 'IDLE' now means 'Integrated Development and Learning
  Environment'.

* bpo-24820: Users can now set breakpoint colors in Settings ->
  Custom Highlighting. Original patch by Mark Roseman.

* bpo-24972: Inactive selection background now matches active
  selection background, as configured by users, on all systems.  Found
  items are now always highlighted on Windows.  Initial patch by Mark
  Roseman.

* bpo-24570: Idle: make calltip and completion boxes appear on Macs
  affected by a tk regression.  Initial patch by Mark Roseman.

* bpo-24988: Idle ScrolledList context menus (used in debugger) now
  work on Mac Aqua. Patch by Mark Roseman.

* bpo-24801: Make right-click for context menu work on Mac Aqua.
  Patch by Mark Roseman.

* bpo-25173: Associate tkinter messageboxes with a specific widget.
  For Mac OSX, make them a 'sheet'.  Patch by Mark Roseman.

* bpo-25198: Enhance the initial html viewer now used for Idle Help.
  Properly indent fixed-pitch text (patch by Mark Roseman). Give code
  snippet a very Sphinx-like light blueish-gray background. Re-use
  initial width and height set by users for shell and editor. When the
  Table of Contents (TOC) menu is used, put the section header at the
  top of the screen.

* bpo-25225: Condense and rewrite Idle doc section on text colors.

* bpo-21995: Explain some differences between IDLE and console
  Python.

* bpo-22820: Explain need for *print* when running file from Idle
  editor.

* bpo-25224: Doc: augment Idle feature list and no-subprocess
  section.

* bpo-25219: Update doc for Idle command line options. Some were
  missing and notes were not correct.

* bpo-24861: Most of idlelib is private and subject to change. Use
  idleib.idle.* to start Idle. See idlelib.__init__.__doc__.

* bpo-25199: Idle: add synchronization comments for future
  maintainers.

* bpo-16893: Replace help.txt with help.html for Idle doc display.
  The new idlelib/help.html is rstripped
  Doc/build/html/library/idle.html. It looks better than help.txt and
  will better document Idle as released. The tkinter html viewer that
  works for this file was written by Rose Roseman. The now unused
  EditorWindow.HelpDialog class and helt.txt file are deprecated.

* bpo-24199: Deprecate unused idlelib.idlever with possible removal
  in 3.6.

* bpo-24790: Remove extraneous code (which also create 2 & 3
  conflicts).


文档
----

* bpo-26736: Used HTTPS for external links in the documentation if
  possible.

* bpo-6953: Rework the Readline module documentation to group
  related functions together, and add more details such as what
  underlying Readline functions and variables are accessed.

* bpo-23606: Adds note to ctypes documentation regarding
  cdll.msvcrt.

* bpo-24952: Clarify the default size argument of stack_size() in
  the "threading" and "_thread" modules. Patch from Mattip.

* bpo-26014: Update 3.x packaging documentation: * "See also" links
  to the new docs are now provided in the legacy pages * links to
  setuptools documentation have been updated


测试
----

* bpo-21916: Added tests for the turtle module.  Patch by ingrid,
  Gregory Loyse and Jelle Zijlstra.

* bpo-26295: When using "python3 -m test --testdir=TESTDIR",
  regrtest doesn't add "test." prefix to test module names.

* bpo-26523: The multiprocessing thread pool
  (multiprocessing.dummy.Pool) was untested.

* bpo-26015: Added new tests for pickling iterators of mutable
  sequences.

* bpo-26325: Added test.support.check_no_resource_warning() to check
  that no ResourceWarning is emitted.

* bpo-25940: Changed test_ssl to use its internal local server more.
  This avoids relying on svn.python.org, which recently changed root
  certificate.

* bpo-25616: Tests for OrderedDict are extracted from
  test_collections into separate file test_ordered_dict.

* bpo-25449: Added tests for OrderedDict subclasses.

* bpo-25188: Add -P/--pgo to test.regrtest to suppress error output
  when running the test suite for the purposes of a PGO build. Initial
  patch by Alecsandru Patrascu.

* bpo-22806: Add "python -m test --list-tests" command to list
  tests.

* bpo-18174: "python -m test --huntrleaks ..." now also checks for
  leak of file descriptors. Patch written by Richard Oudkerk.

* bpo-25260: Fix "python -m test --coverage" on Windows. Remove the
  list of ignored directories.

* "PCbuild\rt.bat" now accepts an unlimited number of arguments to
  pass along to regrtest.py.  Previously there was a limit of 9.

* bpo-26583: Skip test_timestamp_overflow in test_import if bytecode
  files cannot be written.


构建
----

* bpo-21277: Don't try to link _ctypes with a ffi_convenience
  library.

* bpo-26884: Fix linking extension modules for cross builds. Patch
  by Xavier de Gaye.

* bpo-26932: Fixed support of RTLD_* constants defined as enum
  values, not via macros (in particular on Android).  Patch by Chi
  Hsuan Yen.

* bpo-22359: Disable the rules for running _freeze_importlib and
  pgen when cross-compiling.  The output of these programs is normally
  saved with the source code anyway, and is still regenerated when
  doing a native build. Patch by Xavier de Gaye.

* bpo-21668: Link audioop, _datetime, _ctypes_test modules to libm,
  except on Mac OS X. Patch written by Chi Hsuan Yen.

* bpo-25702: A --with-lto configure option has been added that will
  enable link time optimizations at build time during a make profile-
  opt. Some compilers and toolchains are known to not produce stable
  code when using LTO, be sure to test things thoroughly before
  relying on it. It can provide a few % speed up over profile-opt
  alone.

* bpo-26624: Adds validation of ucrtbase[d].dll version with warning
  for old versions.

* bpo-17603: Avoid error about nonexistent fileblocks.o file by
  using a lower-level check for st_blocks in struct stat.

* bpo-26079: Fixing the build output folder for tix-8.4.3.6. Patch
  by Bjoern Thiel.

* bpo-26465: Update Windows builds to use OpenSSL 1.0.2g.

* bpo-25348: Added "--pgo" and "--pgo-job" arguments to
  "PCbuild\build.bat" for building with Profile-Guided Optimization.
  The old "PCbuild\build_pgo.bat" script is removed.

* bpo-25827: Add support for building with ICC to "configure",
  including a new "--with-icc" flag.

* bpo-25696: Fix installation of Python on UNIX with make -j9.

* bpo-24986: It is now possible to build Python on Windows without
  errors when external libraries are not available.

* bpo-24421: Compile Modules/_math.c once, before building
  extensions. Previously it could fail to compile properly if the math
  and cmath builds were concurrent.

* bpo-26465: Update OS X 10.5+ 32-bit-only installer to build and
  link with OpenSSL 1.0.2g.

* bpo-26268: Update Windows builds to use OpenSSL 1.0.2f.

* bpo-25136: Support Apple Xcode 7's new textual SDK stub libraries.

* bpo-24324: Do not enable unreachable code warnings when using gcc
  as the option does not work correctly in older versions of gcc and
  has been silently removed as of gcc-4.5.


Windows
-------

* bpo-27053: Updates make_zip.py to correctly generate library ZIP
  file.

* bpo-26268: Update the prepare_ssl.py script to handle OpenSSL
  releases that don't include the contents of the include directory
  (that is, 1.0.2e and later).

* bpo-26071: bdist_wininst created binaries fail to start and find
  32bit Python

* bpo-26073: Update the list of magic numbers in launcher

* bpo-26065: Excludes venv from library when generating embeddable
  distro.

* bpo-25022: Removed very outdated PC/example_nt/ directory.


工具/示例
---------

* bpo-26799: Fix python-gdb.py: don't get C types once when the
  Python code is loaded, but get C types on demand. The C types can
  change if python-gdb.py is loaded before the Python executable.
  Patch written by Thomas Ilsche.

* bpo-26271: Fix the Freeze tool to properly use flags passed
  through configure. Patch by Daniel Shaulov.

* bpo-26489: Add dictionary unpacking support to
  Tools/parser/unparse.py. Patch by Guo Ci Teo.

* bpo-26316: Fix variable name typo in Argument Clinic.

* bpo-25440: Fix output of python-config --extension-suffix.

* bpo-25154: The pyvenv script has been deprecated in favour of
  "python3 -m venv".


C API
-----

* bpo-26312: SystemError is now raised in all programming bugs with
  using PyArg_ParseTupleAndKeywords().  RuntimeError did raised before
  in some programming bugs.

* bpo-26198: ValueError is now raised instead of TypeError on buffer
  overflow in parsing "es#" and "et#" format units.  SystemError is
  now raised instead of TypeError on programmatical error in parsing
  format string.


Python 3.5.5 final
==================

*Release date: 2018-02-04*

There were no new changes in version 3.5.5.


Python 3.5.5 release candidate 1
================================

*Release date: 2018-01-23*


安全
----

* bpo-32551: The "sys.path[0]" initialization change for bpo-29139
  caused a regression by revealing an inconsistency in how sys.path is
  initialized when executing "__main__" from a zipfile, directory, or
  other import location. This is considered a potential security
  issue, as it may lead to privileged processes unexpectedly loading
  code from user controlled directories in situations where that was
  not previously the case. The interpreter now consistently avoids
  ever adding the import location's parent directory to "sys.path",
  and ensures no other "sys.path" entries are inadvertently modified
  when inserting the import location named on the command line.
  (Originally reported as bpo-29723 against Python 3.6rc1, but it was
  missed at the time that the then upcoming Python 3.5.4 release would
  also be affected)

* bpo-30657: Fixed possible integer overflow in
  PyBytes_DecodeEscape, CVE-2017-1000158. Original patch by Jay
  Bosamiya; rebased to Python 3 by Miro Hrončok.

* bpo-30947: Upgrade libexpat embedded copy from version 2.2.1 to
  2.2.3 to get security fixes.


核心与内置
----------

* bpo-31095: Fix potential crash during GC caused by "tp_dealloc"
  which doesn't call "PyObject_GC_UnTrack()".


库
--

* bpo-32072: Fixed issues with binary plists: Fixed saving
  bytearrays. Identical objects will be saved only once. Equal
  references will be load as identical objects. Added support for
  saving and loading recursive data structures.

* bpo-31170: expat: Update libexpat from 2.2.3 to 2.2.4. Fix copying
  of partial characters for UTF-8 input (libexpat bug 115):
  https://github.com/libexpat/libexpat/issues/115


Python 3.5.4 final
==================

*Release date: 2017-08-07*


库
--

* bpo-30119: ftplib.FTP.putline() now throws ValueError on commands
  that contains CR or LF. Patch by Dong-hee Na.


Python 3.5.4 release candidate 1
================================

*Release date: 2017-07-23*


安全
----

* bpo-30730: Prevent environment variables injection in subprocess
  on Windows.  Prevent passing other environment variables and command
  arguments.

* bpo-30694: Upgrade expat copy from 2.2.0 to 2.2.1 to get fixes of
  multiple security vulnerabilities including: CVE-2017-9233 (External
  entity infinite loop DoS), CVE-2016-9063 (Integer overflow, re-fix),
  CVE-2016-0718 (Fix regression bugs from 2.2.0's fix to
  CVE-2016-0718) and CVE-2012-0876 (Counter hash flooding with
  SipHash). Note: the CVE-2016-5300 (Use os-specific entropy sources
  like getrandom) doesn't impact Python, since Python already gets
  entropy from the OS to set the expat secret using
  "XML_SetHashSalt()".

* bpo-30500: Fix urllib.parse.splithost() to correctly parse
  fragments. For example, "splithost('//127.0.0.1#@evil.com/')" now
  correctly returns the "127.0.0.1" host, instead of treating
  "@evil.com" as the host in an authentication ("login@host").

* bpo-29591: Update expat copy from 2.1.1 to 2.2.0 to get fixes of
  CVE-2016-0718 and CVE-2016-4472. See
  https://sourceforge.net/p/expat/bugs/537/ for more information.


核心与内置
----------

* bpo-30876: Relative import from unloaded package now reimports the
  package instead of failing with SystemError.  Relative import from
  non-package now fails with ImportError rather than SystemError.

* bpo-30765: Avoid blocking in pthread_mutex_lock() when
  PyThread_acquire_lock() is asked not to block.

* bpo-27945: Fixed various segfaults with dict when input
  collections are mutated during searching, inserting or comparing.
  Based on patches by Duane Griffin and Tim Mitchell.

* bpo-25794: Fixed type.__setattr__() and type.__delattr__() for
  non- interned attribute names.  Based on patch by Eryk Sun.

* bpo-29935: Fixed error messages in the index() method of tuple,
  list and deque when pass indices of wrong type.

* bpo-28876: "bool(range)" works even if "len(range)" raises
  "OverflowError".

* bpo-29600: Fix wrapping coroutine return values in StopIteration.

* bpo-29537: Restore runtime compatibility with bytecode files
  generated by CPython 3.5.0 to 3.5.2, and adjust the eval loop to
  avoid the problems that could be caused by the malformed variant of
  the BUILD_MAP_UNPACK_WITH_CALL opcode that they may contain. Patch
  by Petr Viktorin, Serhiy Storchaka, and Nick Coghlan.

* bpo-28598: Support __rmod__ for subclasses of str being called
  before str.__mod__. Patch by Martijn Pieters.

* bpo-29602: Fix incorrect handling of signed zeros in complex
  constructor for complex subclasses and for inputs having a
  __complex__ method. Patch by Serhiy Storchaka.

* bpo-29347: Fixed possibly dereferencing undefined pointers when
  creating weakref objects.

* bpo-29438: Fixed use-after-free problem in key sharing dict.

* bpo-29319: Prevent RunMainFromImporter overwriting sys.path[0].

* bpo-29337: Fixed possible BytesWarning when compare the code
  objects. Warnings could be emitted at compile time.

* bpo-29478: If max_line_length=None is specified while using the
  Compat32 policy, it is no longer ignored.  Patch by Mircea Cosbuc.


库
--

* bpo-29403: Fix "unittest.mock"'s autospec to not fail on method-
  bound builtin functions.  Patch by Aaron Gallagher.

* bpo-30961: Fix decrementing a borrowed reference in tracemalloc.

* bpo-30886: Fix multiprocessing.Queue.join_thread(): it now waits
  until the thread completes, even if the thread was started by the
  same process which created the queue.

* bpo-29854: Fix segfault in readline when using readline's history-
  size option.  Patch by Nir Soffer.

* bpo-30807: signal.setitimer() may disable the timer when passed a
  tiny value. Tiny values (such as 1e-6) are valid non-zero values for
  setitimer(), which is specified as taking microsecond-resolution
  intervals. However, on some platform, our conversion routine could
  convert 1e-6 into a zero interval, therefore disabling the timer
  instead of (re-)scheduling it.

* bpo-30441: Fix bug when modifying os.environ while iterating over
  it

* bpo-30532: Fix email header value parser dropping folding white
  space in certain cases.

* bpo-29169: Update zlib to 1.2.11.

* bpo-30879: os.listdir() and os.scandir() now emit bytes names when
  called with bytes-like argument.

* bpo-30746: Prohibited the '=' character in environment variable
  names in "os.putenv()" and "os.spawn*()".

* bpo-29755: Fixed the lgettext() family of functions in the gettext
  module. They now always return bytes.

* bpo-30645: Fix path calculation in imp.load_package(), fixing it
  for cases when a package is only shipped with bytecodes. Patch by
  Alexandru Ardelean.

* bpo-23890: unittest.TestCase.assertRaises() now manually breaks a
  reference cycle to not keep objects alive longer than expected.

* bpo-30149: inspect.signature() now supports callables with
  variable- argument parameters wrapped with partialmethod. Patch by
  Dong-hee Na.

* bpo-29931: Fixed comparison check for ipaddress.ip_interface
  objects. Patch by Sanjay Sundaresan.

* bpo-24484: Avoid race condition in multiprocessing cleanup.

* bpo-28994: The traceback no longer displayed for SystemExit raised
  in a callback registered by atexit.

* bpo-30508: Don't log exceptions if Task/Future "cancel()" method
  was called.

* bpo-28556: Updates to typing module: Add generic
  AsyncContextManager, add support for ContextManager on all versions.
  Original PRs by Jelle Zijlstra and Ivan Levkivskyi

* bpo-29870: Fix ssl sockets leaks when connection is aborted in
  asyncio/ssl implementation. Patch by Michaël Sghaïer.

* bpo-29743: Closing transport during handshake process leaks open
  socket. Patch by Nikolay Kim

* bpo-27585: Fix waiter cancellation in asyncio.Lock. Patch by
  Mathieu Sornay.

* bpo-30418: On Windows, subprocess.Popen.communicate() now also
  ignore EINVAL on stdin.write() if the child process is still running
  but closed the pipe.

* bpo-30378: Fix the problem that logging.handlers.SysLogHandler
  cannot handle IPv6 addresses.

* bpo-29960: Preserve generator state when _random.Random.setstate()
  raises an exception. Patch by Bryan Olson.

* bpo-30414: multiprocessing.Queue._feed background running thread
  do not break from main loop on exception.

* bpo-30003: Fix handling escape characters in HZ codec.  Based on
  patch by Ma Lin.

* bpo-30301: Fix AttributeError when using SimpleQueue.empty() under
  *spawn* and *forkserver* start methods.

* bpo-30329: imaplib and poplib now catch the Windows socket
  WSAEINVAL error (code 10022) on shutdown(SHUT_RDWR): An invalid
  operation was attempted. This error occurs sometimes on SSL
  connections.

* bpo-30375: Warnings emitted when compile a regular expression now
  always point to the line in the user code.  Previously they could
  point into inners of the re module if emitted from inside of groups
  or conditionals.

* bpo-30048: Fixed "Task.cancel()" can be ignored when the task is
  running coroutine and the coroutine returned without any more
  "await".

* bpo-29990: Fix range checking in GB18030 decoder.  Original patch
  by Ma Lin.

* bpo-26293: Change resulted because of zipfile breakage. (See also:
  bpo-29094)

* bpo-30243: Removed the __init__ methods of _json's scanner and
  encoder. Misusing them could cause memory leaks or crashes.  Now
  scanner and encoder objects are completely initialized in the
  __new__ methods.

* bpo-30185: Avoid KeyboardInterrupt tracebacks in forkserver helper
  process when Ctrl-C is received.

* bpo-28556: Various updates to typing module: add typing.NoReturn
  type, use WrapperDescriptorType, minor bug-fixes.  Original PRs by
  Jim Fasarakis-Hilliard and Ivan Levkivskyi.

* bpo-30205: Fix getsockname() for unbound AF_UNIX sockets on Linux.

* bpo-30070: Fixed leaks and crashes in errors handling in the
  parser module.

* bpo-30061: Fixed crashes in IOBase methods __next__() and
  readlines() when readline() or __next__() respectively return non-
  sizeable object. Fixed possible other errors caused by not checking
  results of PyObject_Size(), PySequence_Size(), or PyMapping_Size().

* bpo-30068: _io._IOBase.readlines will check if it's closed first
  when hint is present.

* bpo-29694: Fixed race condition in pathlib mkdir with flags
  parents=True. Patch by Armin Rigo.

* bpo-29692: Fixed arbitrary unchaining of RuntimeError exceptions
  in contextlib.contextmanager.  Patch by Siddharth Velankar.

* bpo-29998: Pickling and copying ImportError now preserves name and
  path attributes.

* bpo-29942: Fix a crash in itertools.chain.from_iterable when
  encountering long runs of empty iterables.

* bpo-27863: Fixed multiple crashes in ElementTree caused by race
  conditions and wrong types.

* bpo-28699: Fixed a bug in pools in multiprocessing.pool that
  raising an exception at the very first of an iterable may swallow
  the exception or make the program hang. Patch by Davin Potts and
  Xiang Zhang.

* bpo-25803: Avoid incorrect errors raised by
  Path.mkdir(exist_ok=True) when the OS gives priority to errors such
  as EACCES over EEXIST.

* bpo-29861: Release references to tasks, their arguments and their
  results as soon as they are finished in multiprocessing.Pool.

* bpo-29884: faulthandler: Restore the old sigaltstack during
  teardown. Patch by Christophe Zeitouny.

* bpo-25455: Fixed crashes in repr of recursive buffered file-like
  objects.

* bpo-29800: Fix crashes in partial.__repr__ if the keys of
  partial.keywords are not strings.  Patch by Michael Seifert.

* bpo-29742: get_extra_info() raises exception if get called on
  closed ssl transport. Patch by Nikolay Kim.

* bpo-8256: Fixed possible failing or crashing input() if attributes
  "encoding" or "errors" of sys.stdin or sys.stdout are not set or are
  not strings.

* bpo-28298: Fix a bug that prevented array 'Q', 'L' and 'I' from
  accepting big intables (objects that have __int__) as elements.
  Patch by Oren Milman.

* bpo-29615: SimpleXMLRPCDispatcher no longer chains KeyError (or
  any other exception) to exception(s) raised in the dispatched
  methods. Patch by Petr Motejlek.

* bpo-29704: asyncio.subprocess.SubprocessStreamProtocol no longer
  closes before all pipes are closed.

* bpo-29703: Fix asyncio to support instantiation of new event loops
  in child processes.

* bpo-29376: Fix assertion error in
  threading._DummyThread.is_alive().

* bpo-29110: Fix file object leak in aifc.open() when file is given
  as a filesystem path and is not in valid AIFF format. Patch by
  Anthony Zhang.

* bpo-28961: Fix unittest.mock._Call helper: don't ignore the name
  parameter anymore. Patch written by Jiajun Huang.

* bpo-29532: Altering a kwarg dictionary passed to
  functools.partial() no longer affects a partial object after
  creation.

* bpo-28556: Various updates to typing module: typing.Counter,
  typing.ChainMap, improved ABC caching, etc. Original PRs by Jelle
  Zijlstra, Ivan Levkivskyi, Manuel Krebber, and Łukasz Langa.

* bpo-29100: Fix datetime.fromtimestamp() regression introduced in
  Python 3.6.0: check minimum and maximum years.

* bpo-29519: Fix weakref spewing exceptions during interpreter
  shutdown when used with a rare combination of multiprocessing and
  custom codecs.

* bpo-29416: Prevent infinite loop in pathlib.Path.mkdir

* bpo-29444: Fixed out-of-bounds buffer access in the group() method
  of the match object. Based on patch by WGH.

* bpo-29335: Fix subprocess.Popen.wait() when the child process has
  exited to a stopped instead of terminated state (ex: when under
  ptrace).

* bpo-29290: Fix a regression in argparse that help messages would
  wrap at non-breaking spaces.

* bpo-28735: Fixed the comparison of mock.MagickMock with mock.ANY.

* bpo-29011: Fix an important omission by adding Deque to the typing
  module.

* bpo-29219: Fixed infinite recursion in the repr of uninitialized
  ctypes.CDLL instances.

* bpo-28969: Fixed race condition in C implementation of
  functools.lru_cache. KeyError could be raised when cached function
  with full cache was simultaneously called from different threads
  with the same uncached arguments.

* bpo-29142: In urllib.request, suffixes in no_proxy environment
  variable with leading dots could match related hostnames again (e.g.
  .b.c matches a.b.c). Patch by Milan Oberkirch.


文档
----

* bpo-30176: Add missing attribute related constants in curses
  documentation.

* bpo-26985: Add missing info of code object in inspect
  documentation.

* bpo-28929: Link the documentation to its source file on GitHub.

* bpo-25008: Document smtpd.py as effectively deprecated and add a
  pointer to aiosmtpd, a third-party asyncio-based replacement.

* bpo-26355: Add canonical header link on each page to corresponding
  major version of the documentation. Patch by Matthias Bussonnier.

* bpo-29349: Fix Python 2 syntax in code for building the
  documentation.


测试
----

* bpo-30822: Fix regrtest command line parser to allow passing -u
  extralargefile to run test_zipfile64.

* bpo-30383: regrtest: Enhance regrtest and backport features from
  the master branch. Add options: --coverage, --testdir, --list-tests
  (list test files, don't run them), --list-cases (list test
  identifiers, don't run them, bpo-30523), --matchfile (load a list of
  test filters from a text file, bpo-30540), --slowest (alias to
  --slow). Enhance output: add timestamp, test result, currently
  running tests, "Tests result: xxx" summary with total duration, etc.
  Fix reference leak hunting in regrtest, --huntrleaks: regrtest now
  warms up caches, create explicitly all internal singletons which are
  created on demand to prevent false positives when checking for
  reference leaks. (bpo-30675).

* bpo-30357: test_thread: setUp() now uses support.threading_setup()
  and support.threading_cleanup() to wait until threads complete to
  avoid random side effects on following tests. Initial patch written
  by Grzegorz Grzywacz.

* bpo-28087: Skip test_asyncore and test_eintr poll failures on
  macOS. Skip some tests of select.poll when running on macOS due to
  unresolved issues with the underlying system poll function on some
  macOS versions.

* bpo-30197: Enhanced functions swap_attr() and swap_item() in the
  test.support module. They now work when delete replaced attribute or
  item inside the with statement.  The old value of the attribute or
  item (or None if it doesn't exist) now will be assigned to the
  target of the "as" clause, if there is one.

* bpo-29571: to match the behaviour of the "re.LOCALE" flag,
  test_re.test_locale_flag now uses
  "locale.getpreferredencoding(False)" to determine the candidate
  encoding for the test regex (allowing it to correctly skip the test
  when the default locale encoding is a multi-byte encoding)


构建
----

* bpo-29243: Prevent unnecessary rebuilding of Python during "make
  test", "make install" and some other make targets when configured
  with "--enable-optimizations".

* bpo-23404: Don't regenerate generated files based on file
  modification time anymore: the action is now explicit. Replace "make
  touch" with "make regen-all".

* bpo-29643: Fix "--enable-optimization" didn't work.


Windows
-------

* bpo-30687: Locate msbuild.exe on Windows when building rather than
  vcvarsall.bat

* bpo-29392: Prevent crash when passing invalid arguments into
  msvcrt module.


C API
-----

* bpo-27867: Function PySlice_GetIndicesEx() is replaced with a
  macro if Py_LIMITED_API is set to the value between 0x03050400 and
  0x03060000 (not including) or 0x03060100 or higher.

* bpo-29083: Fixed the declaration of some public API functions.
  PyArg_VaParse() and PyArg_VaParseTupleAndKeywords() were not
  available in limited API. PyArg_ValidateKeywordArguments(),
  PyArg_UnpackTuple() and Py_BuildValue() were not available in
  limited API of version < 3.3 when PY_SSIZE_T_CLEAN is defined.


Python 3.5.3 final
==================

*Release date: 2017-01-17*

There were no code changes between 3.5.3rc1 and 3.5.3 final.


Python 3.5.3 release candidate 1
================================

*Release date: 2017-01-02*


核心与内置
----------

* bpo-29073: bytearray formatting no longer truncates on first null
  byte.

* bpo-28932: Do not include <sys/random.h> if it does not exist.

* bpo-28147: Fix a memory leak in split-table dictionaries:
  setattr() must not convert combined table into split table.

* bpo-25677: Correct the positioning of the syntax error caret for
  indented blocks. Based on patch by Michael Layzell.

* bpo-29000: Fixed bytes formatting of octals with zero padding in
  alternate form.

* bpo-28512: Fixed setting the offset attribute of SyntaxError by
  PyErr_SyntaxLocationEx() and PyErr_SyntaxLocationObject().

* bpo-28991: functools.lru_cache() was susceptible to an obscure
  reentrancy bug caused by a monkey-patched len() function.

* bpo-28648: Fixed crash in Py_DecodeLocale() in debug build on Mac
  OS X when decode astral characters.  Patch by Xiang Zhang.

* bpo-19398: Extra slash no longer added to sys.path components in
  case of empty compile-time PYTHONPATH components.

* bpo-28426: Fixed potential crash in PyUnicode_AsDecodedObject() in
  debug build.

* bpo-23782: Fixed possible memory leak in _PyTraceback_Add() and
  exception loss in PyTraceBack_Here().

* bpo-28379: Added sanity checks and tests for
  PyUnicode_CopyCharacters(). Patch by Xiang Zhang.

* bpo-28376: The type of long range iterator is now registered as
  Iterator. Patch by Oren Milman.

* bpo-28376: The constructor of range_iterator now checks that step
  is not 0. Patch by Oren Milman.

* bpo-26906: Resolving special methods of uninitialized type now
  causes implicit initialization of the type instead of a fail.

* bpo-18287: PyType_Ready() now checks that tp_name is not NULL.
  Original patch by Niklas Koep.

* bpo-24098: Fixed possible crash when AST is changed in process of
  compiling it.

* bpo-28350: String constants with null character no longer
  interned.

* bpo-26617: Fix crash when GC runs during weakref callbacks.

* bpo-27942: String constants now interned recursively in tuples and
  frozensets.

* bpo-21578: Fixed misleading error message when ImportError called
  with invalid keyword args.

* bpo-28203: Fix incorrect type in error message from "complex(1.0,
  {2:3})". Patch by Soumya Sharma.

* bpo-27955: Fallback on reading /dev/urandom device when the
  getrandom() syscall fails with EPERM, for example when blocked by
  SECCOMP.

* bpo-28131: Fix a regression in zipimport's compile_source().
  zipimport should use the same optimization level as the interpreter.

* bpo-25221: Fix corrupted result from PyLong_FromLong(0) when
  Python is compiled with NSMALLPOSINTS = 0.

* bpo-25758: Prevents zipimport from unnecessarily encoding a
  filename (patch by Eryk Sun)

* bpo-28189: dictitems_contains no longer swallows compare errors.
  (Patch by Xiang Zhang)

* bpo-27812: Properly clear out a generator's frame's backreference
  to the generator to prevent crashes in frame.clear().

* bpo-27811: Fix a crash when a coroutine that has not been awaited
  is finalized with warnings-as-errors enabled.

* bpo-27587: Fix another issue found by PVS-Studio: Null pointer
  check after use of 'def' in _PyState_AddModule(). Initial patch by
  Christian Heimes.

* bpo-26020: set literal evaluation order did not match documented
  behaviour.

* bpo-27782: Multi-phase extension module import now correctly
  allows the "m_methods" field to be used to add module level
  functions to instances of non-module types returned from
  "Py_create_mod". Patch by Xiang Zhang.

* bpo-27936: The round() function accepted a second None argument
  for some types but not for others.  Fixed the inconsistency by
  accepting None for all numeric types.

* bpo-27487: Warn if a submodule argument to "python -m" or
  runpy.run_module() is found in sys.modules after parent packages are
  imported, but before the submodule is executed.

* bpo-27558: Fix a SystemError in the implementation of "raise"
  statement. In a brand new thread, raise a RuntimeError since there
  is no active exception to reraise. Patch written by Xiang Zhang.

* bpo-27419: Standard __import__() no longer look up "__import__" in
  globals or builtins for importing submodules or "from import". Fixed
  handling an error of non-string package name.

* bpo-27083: Respect the PYTHONCASEOK environment variable under
  Windows.

* bpo-27514: Make having too many statically nested blocks a
  SyntaxError instead of SystemError.

* bpo-27473: Fixed possible integer overflow in bytes and bytearray
  concatenations. Patch by Xiang Zhang.

* bpo-27507: Add integer overflow check in bytearray.extend().
  Patch by Xiang Zhang.

* bpo-27581: Don't rely on wrapping for overflow check in
  PySequence_Tuple().  Patch by Xiang Zhang.

* bpo-27443: __length_hint__() of bytearray iterators no longer
  return a negative integer for a resized bytearray.

* bpo-27942: Fix memory leak in codeobject.c


库
--

* bpo-15812: inspect.getframeinfo() now correctly shows the first
  line of a context. Patch by Sam Breese.

* bpo-29094: Offsets in a ZIP file created with extern file object
  and modes "w" and "x" now are relative to the start of the file.

* bpo-13051: Fixed recursion errors in large or resized
  curses.textpad.Textbox.  Based on patch by Tycho Andersen.

* bpo-29119: Fix weakrefs in the pure python version of
  collections.OrderedDict move_to_end() method. Contributed by Andra
  Bogildea.

* bpo-9770: curses.ascii predicates now work correctly with negative
  integers.

* bpo-28427: old keys should not remove new values from
  WeakValueDictionary when collecting from another thread.

* bpo-28923: Remove editor artifacts from Tix.py.

* bpo-28871: Fixed a crash when deallocate deep ElementTree.

* bpo-19542: Fix bugs in WeakValueDictionary.setdefault() and
  WeakValueDictionary.pop() when a GC collection happens in another
  thread.

* bpo-20191: Fixed a crash in resource.prlimit() when pass a
  sequence that doesn't own its elements as limits.

* bpo-28779: multiprocessing.set_forkserver_preload() would crash
  the forkserver process if a preloaded module instantiated some
  multiprocessing objects such as locks.

* bpo-28847: dbm.dumb now supports reading read-only files and no
  longer writes the index file when it is not changed.

* bpo-25659: In ctypes, prevent a crash calling the from_buffer()
  and from_buffer_copy() methods on abstract classes like Array.

* bpo-28732: Fix crash in os.spawnv() with no elements in args

* bpo-28485: Always raise ValueError for negative
  compileall.compile_dir(workers=...) parameter, even when
  multithreading is unavailable.

* bpo-28387: Fixed possible crash in _io.TextIOWrapper deallocator
  when the garbage collector is invoked in other thread.  Based on
  patch by Sebastian Cufre.

* bpo-27517: LZMA compressor and decompressor no longer raise
  exceptions if given empty data twice.  Patch by Benjamin Fogle.

* bpo-28549: Fixed segfault in curses's addch() with ncurses6.

* bpo-28449: tarfile.open() with mode "r" or "r:" now tries to open
  a tar file with compression before trying to open it without
  compression. Otherwise it had 50% chance failed with
  ignore_zeros=True.

* bpo-23262: The webbrowser module now supports Firefox 36+ and
  derived browsers.  Based on patch by Oleg Broytman.

* bpo-27939: Fixed bugs in tkinter.ttk.LabeledScale and
  tkinter.Scale caused by representing the scale as float value
  internally in Tk. tkinter.IntVar now works if float value is set to
  underlying Tk variable.

* bpo-28255: calendar.TextCalendar().prmonth() no longer prints a
  space at the start of new line after printing a month's calendar.
  Patch by Xiang Zhang.

* bpo-20491: The textwrap.TextWrapper class now honors non-breaking
  spaces. Based on patch by Kaarle Ritvanen.

* bpo-28353: os.fwalk() no longer fails on broken links.

* bpo-25464: Fixed HList.header_exists() in tkinter.tix module by
  addin a workaround to Tix library bug.

* bpo-28488: shutil.make_archive() no longer add entry "./" to ZIP
  archive.

* bpo-24452: Make webbrowser support Chrome on Mac OS X.

* bpo-20766: Fix references leaked by pdb in the handling of SIGINT
  handlers.

* bpo-26293: Fixed writing ZIP files that starts not from the start
  of the file.  Offsets in ZIP file now are relative to the start of
  the archive in conforming to the specification.

* bpo-28321: Fixed writing non-BMP characters with binary format in
  plistlib.

* bpo-28322: Fixed possible crashes when unpickle itertools objects
  from incorrect pickle data.  Based on patch by John Leitch.

* Fix possible integer overflows and crashes in the mmap module with
  unusual usage patterns.

* bpo-1703178: Fix the ability to pass the --link-objects option to
  the distutils build_ext command.

* bpo-28253: Fixed calendar functions for extreme months: 0001-01
  and 9999-12. Methods itermonthdays() and itermonthdays2() are
  reimplemented so that they don't call itermonthdates() which can
  cause datetime.date under/overflow.

* bpo-28275: Fixed possible use after free in the decompress()
  methods of the LZMADecompressor and BZ2Decompressor classes.
  Original patch by John Leitch.

* bpo-27897: Fixed possible crash in
  sqlite3.Connection.create_collation() if pass invalid string-like
  object as a name.  Patch by Xiang Zhang.

* bpo-18893: Fix invalid exception handling in
  Lib/ctypes/macholib/dyld.py. Patch by Madison May.

* bpo-27611: Fixed support of default root window in the tkinter.tix
  module.

* bpo-27348: In the traceback module, restore the formatting of
  exception messages like "Exception: None".  This fixes a regression
  introduced in 3.5a2.

* bpo-25651: Allow falsy values to be used for msg parameter of
  subTest().

* bpo-27932: Prevent memory leak in win32_ver().

* Fix UnboundLocalError in socket._sendfile_use_sendfile.

* bpo-28075: Check for ERROR_ACCESS_DENIED in Windows implementation
  of os.stat().  Patch by Eryk Sun.

* bpo-25270: Prevent codecs.escape_encode() from raising SystemError
  when an empty bytestring is passed.

* bpo-28181: Get antigravity over HTTPS. Patch by Kaartic Sivaraam.

* bpo-25895: Enable WebSocket URL schemes in urllib.parse.urljoin.
  Patch by Gergely Imreh and Markus Holtermann.

* bpo-27599: Fixed buffer overrun in binascii.b2a_qp() and
  binascii.a2b_qp().

* bpo-19003: m email.generator now replaces only "\r" and/or "\n"
  line endings, per the RFC, instead of all unicode line endings.

* bpo-28019: itertools.count() no longer rounds non-integer step in
  range between 1.0 and 2.0 to 1.

* bpo-25969: Update the lib2to3 grammar to handle the unpacking
  generalizations added in 3.5.

* bpo-14977: mailcap now respects the order of the lines in the
  mailcap files ("first match"), as required by RFC 1542.  Patch by
  Michael Lazar.

* bpo-24594: Validates persist parameter when opening MSI database

* bpo-17582: xml.etree.ElementTree nows preserves whitespaces in
  attributes (Patch by Duane Griffin.  Reviewed and approved by Stefan
  Behnel.)

* bpo-28047: Fixed calculation of line length used for the base64
  CTE in the new email policies.

* bpo-27445: Don't pass str(_charset) to MIMEText.set_payload().
  Patch by Claude Paroz.

* bpo-22450: urllib now includes an "Accept: */*" header among the
  default headers. This makes the results of REST API requests more
  consistent and predictable especially when proxy servers are
  involved.

* lib2to3.pgen3.driver.load_grammar() now creates a stable cache
  file between runs given the same Grammar.txt input regardless of the
  hash randomization setting.

* bpo-27570: Avoid zero-length memcpy() etc calls with null source
  pointers in the "ctypes" and "array" modules.

* bpo-22233: Break email header lines *only* on the RFC specified CR
  and LF characters, not on arbitrary unicode line breaks.  This also
  fixes a bug in HTTP header parsing.

* bpo-27988: Fix email iter_attachments incorrect mutation of
  payload list.

* bpo-27691: Fix ssl module's parsing of GEN_RID subject alternative
  name fields in X.509 certs.

* bpo-27850: Remove 3DES from ssl module's default cipher list to
  counter measure sweet32 attack (CVE-2016-2183).

* bpo-27766: Add ChaCha20 Poly1305 to ssl module's default cipher
  list. (Required OpenSSL 1.1.0 or LibreSSL).

* bpo-26470: Port ssl and hashlib module to OpenSSL 1.1.0.

* Remove support for passing a file descriptor to os.access. It
  never worked but previously didn't raise.

* bpo-12885: Fix error when distutils encounters symlink.

* bpo-27881: Fixed possible bugs when setting
  sqlite3.Connection.isolation_level. Based on patch by Xiang Zhang.

* bpo-27861: Fixed a crash in sqlite3.Connection.cursor() when a
  factory creates not a cursor.  Patch by Xiang Zhang.

* bpo-19884: Avoid spurious output on OS X with Gnu Readline.

* bpo-27706: Restore deterministic behavior of
  random.Random().seed() for string seeds using seeding version 1.
  Allows sequences of calls to random() to exactly match those
  obtained in Python 2. Patch by Nofar Schnider.

* bpo-10513: Fix a regression in Connection.commit().  Statements
  should not be reset after a commit.

* A new version of typing.py from https://github.com/python/typing:
  Collection (only for 3.6) (bpo-27598). Add FrozenSet to __all__
  (upstream #261). Fix crash in _get_type_vars() (upstream #259).
  Remove the dict constraint in ForwardRef._eval_type (upstream #252).

* bpo-27539: Fix unnormalised "Fraction.__pow__" result in the case
  of negative exponent and negative base.

* bpo-21718: cursor.description is now available for queries using
  CTEs.

* bpo-2466: posixpath.ismount now correctly recognizes mount points
  which the user does not have permission to access.

* bpo-27773: Correct some memory management errors server_hostname
  in _ssl.wrap_socket().

* bpo-26750: unittest.mock.create_autospec() now works properly for
  subclasses of property() and other data descriptors.

* In the curses module, raise an error if window.getstr() or
  window.instr() is passed a negative value.

* bpo-27783: Fix possible usage of uninitialized memory in
  operator.methodcaller.

* bpo-27774: Fix possible Py_DECREF on unowned object in _sre.

* bpo-27760: Fix possible integer overflow in binascii.b2a_qp.

* bpo-27758: Fix possible integer overflow in the _csv module for
  large record lengths.

* bpo-27568: Prevent HTTPoxy attack (CVE-2016-1000110). Ignore the
  HTTP_PROXY variable when REQUEST_METHOD environment is set, which
  indicates that the script is in CGI mode.

* bpo-27656: Do not assume sched.h defines any SCHED_* constants.

* bpo-27130: In the "zlib" module, fix handling of large buffers
  (typically 4 GiB) when compressing and decompressing.  Previously,
  inputs were limited to 4 GiB, and compression and decompression
  operations did not properly handle results of 4 GiB.

* bpo-27533: Release GIL in nt._isdir

* bpo-17711: Fixed unpickling by the persistent ID with protocol 0.
  Original patch by Alexandre Vassalotti.

* bpo-27522: Avoid an unintentional reference cycle in
  email.feedparser.

* bpo-26844: Fix error message for imp.find_module() to refer to
  'path' instead of 'name'. Patch by Lev Maximov.

* bpo-23804: Fix SSL zero-length recv() calls to not block and not
  raise an error about unclean EOF.

* bpo-27466: Change time format returned by
  http.cookie.time2netscape, confirming the netscape cookie format and
  making it consistent with documentation.

* bpo-26664: Fix activate.fish by removing mis-use of "$".

* bpo-22115: Fixed tracing Tkinter variables: trace_vdelete() with
  wrong mode no longer break tracing, trace_vinfo() now always returns
  a list of pairs of strings, tracing in the "u" mode now works.

* Fix a scoping issue in importlib.util.LazyLoader which triggered
  an UnboundLocalError when lazy-loading a module that was already put
  into sys.modules.

* bpo-27079: Fixed curses.ascii functions isblank(), iscntrl() and
  ispunct().

* bpo-26754: Some functions (compile() etc) accepted a filename
  argument encoded as an iterable of integers. Now only strings and
  byte-like objects are accepted.

* bpo-27048: Prevents distutils failing on Windows when environment
  variables contain non-ASCII characters

* bpo-27330: Fixed possible leaks in the ctypes module.

* bpo-27238: Got rid of bare excepts in the turtle module.  Original
  patch by Jelle Zijlstra.

* bpo-27122: When an exception is raised within the context being
  managed by a contextlib.ExitStack() and one of the exit stack
  generators catches and raises it in a chain, do not re-raise the
  original exception when exiting, let the new chained one through.
  This avoids the **PEP 479** bug described in issue25782.


安全
----

* bpo-27278: Fix os.urandom() implementation using getrandom() on
  Linux. Truncate size to INT_MAX and loop until we collected enough
  random bytes, instead of casting a directly Py_ssize_t to int.


库
--

* bpo-26386: Fixed ttk.TreeView selection operations with item id's
  containing spaces.


安全
----

* bpo-22636: Avoid shell injection problems with
  ctypes.util.find_library().


库
--

* bpo-16182: Fix various functions in the "readline" module to use
  the locale encoding, and fix get_begidx() and get_endidx() to return
  code point indexes.

* bpo-27392: Add loop.connect_accepted_socket(). Patch by Jim
  Fulton.

* bpo-27930: Improved behaviour of logging.handlers.QueueListener.
  Thanks to Paulo Andrade and Petr Viktorin for the analysis and
  patch.

* bpo-21201: Improves readability of multiprocessing error message.
  Thanks to Wojciech Walczak for patch.

* bpo-27456: asyncio: Set TCP_NODELAY by default.

* bpo-27906: Fix socket accept exhaustion during high TCP traffic.
  Patch by Kevin Conway.

* bpo-28174: Handle when SO_REUSEPORT isn't properly supported.
  Patch by Seth Michael Larson.

* bpo-26654: Inspect functools.partial in asyncio.Handle.__repr__.
  Patch by iceboy.

* bpo-26909: Fix slow pipes IO in asyncio. Patch by INADA Naoki.

* bpo-28176: Fix callbacks race in
  asyncio.SelectorLoop.sock_connect.

* bpo-27759: Fix selectors incorrectly retain invalid file
  descriptors. Patch by Mark Williams.

* bpo-28368: Refuse monitoring processes if the child watcher has no
  loop attached. Patch by Vincent Michel.

* bpo-28369: Raise RuntimeError when transport's FD is used with
  add_reader, add_writer, etc.

* bpo-28370: Speedup asyncio.StreamReader.readexactly. Patch by
  Коренберг Марк.

* bpo-28371: Deprecate passing asyncio.Handles to run_in_executor.

* bpo-28372: Fix asyncio to support formatting of non-python
  coroutines.

* bpo-28399: Remove UNIX socket from FS before binding. Patch by
  Коренберг Марк.

* bpo-27972: Prohibit Tasks to await on themselves.

* bpo-26923: Fix asyncio.Gather to refuse being cancelled once all
  children are done. Patch by Johannes Ebke.

* bpo-26796: Don't configure the number of workers for default
  threadpool executor. Initial patch by Hans Lawrenz.

* bpo-28600: Optimize loop.call_soon().

* bpo-28613: Fix get_event_loop() return the current loop if called
  from coroutines/callbacks.

* bpo-28639: Fix inspect.isawaitable to always return bool Patch by
  Justin Mayfield.

* bpo-28652: Make loop methods reject socket kinds they do not
  support.

* bpo-28653: Fix a refleak in functools.lru_cache.

* bpo-28703: Fix asyncio.iscoroutinefunction to handle Mock objects.

* bpo-24142: Reading a corrupt config file left the parser in an
  invalid state.  Original patch by Florian Höch.

* bpo-28990: Fix SSL hanging if connection is closed before
  handshake completed. (Patch by HoHo-Ho)


IDLE
----

* bpo-15308: Add 'interrupt execution' (^C) to Shell menu. Patch by
  Roger Serwy, updated by Bayard Randel.

* bpo-27922: Stop IDLE tests from 'flashing' gui widgets on the
  screen.

* 在 IDLE 帮助窗口的标题中加入版本号

* bpo-25564: In section on IDLE -- console differences, mention that
  using exec means that __builtins__ is defined for each statement.

* bpo-27714: text_textview and test_autocomplete now pass when re-
  run in the same process.  This occurs when test_idle fails when run
  with the -w option but without -jn.  Fix warning from test_config.

* bpo-25507: IDLE no longer runs buggy code because of its tkinter
  imports. Users must include the same imports required to run
  directly in Python.

* bpo-27452: add line counter and crc to IDLE configHandler test
  dump.

* bpo-27365: Allow non-ascii chars in IDLE NEWS.txt, for contributor
  names.

* bpo-27245: IDLE: Cleanly delete custom themes and key bindings.
  Previously, when IDLE was started from a console or by import, a
  cascade of warnings was emitted. Patch by Serhiy Storchaka.


C API
-----

* bpo-28808: PyUnicode_CompareWithASCIIString() now never raises
  exceptions.

* bpo-26754: PyUnicode_FSDecoder() accepted a filename argument
  encoded as an iterable of integers. Now only strings and bytes-like
  objects are accepted.


文档
----

* bpo-28513: Documented command-line interface of zipfile.


测试
----

* bpo-28950: Disallow -j0 to be combined with -T/-l/-M in regrtest
  command line arguments.

* bpo-28666: Now test.support.rmtree is able to remove unwritable or
  unreadable directories.

* bpo-23839: Various caches now are cleared before running every
  test file.

* bpo-28409: regrtest: fix the parser of command line arguments.

* bpo-27787: Call gc.collect() before checking each test for
  "dangling threads", since the dangling threads are weak references.

* bpo-27369: In test_pyexpat, avoid testing an error message detail
  that changed in Expat 2.2.0.


工具/示例
---------

* bpo-27952: Get Tools/scripts/fixcid.py working with Python 3 and
  the current "re" module, avoid invalid Python backslash escapes, and
  fix a bug parsing escaped C quote signs.

* bpo-27332: Fixed the type of the first argument of module-level
  functions generated by Argument Clinic.  Patch by Petr Viktorin.

* bpo-27418: Fixed Tools/importbench/importbench.py.


Windows
-------

* bpo-28251: Improvements to help manuals on Windows.

* bpo-28110: launcher.msi has different product codes between 32-bit
  and 64-bit

* bpo-25144: Ensures TargetDir is set before continuing with custom
  install.

* bpo-27469: Adds a shell extension to the launcher so that drag and
  drop works correctly.

* bpo-27309: Enabled proper Windows styles in python[w].exe
  manifest.


构建
----

* bpo-29080: Removes hard dependency on hg.exe from
  PCBuild/build.bat

* bpo-23903: Added missed names to PC/python3.def.

* bpo-10656: Fix out-of-tree building on AIX.  Patch by Tristan
  Carel and Michael Haubenwallner.

* bpo-26359: Rename --with-optimiations to --enable-optimizations.

* bpo-28444: Fix missing extensions modules when cross compiling.

* bpo-28248: Update Windows build and OS X installers to use OpenSSL
  1.0.2j.

* bpo-28258: Fixed build with Estonian locale (python-config and
  distclean targets in Makefile).  Patch by Arfrever Frehtes Taifersar
  Arahesis.

* bpo-26661: setup.py now detects system libffi with multiarch
  wrapper.

* bpo-28066: Fix the logic that searches build directories for
  generated include files when building outside the source tree.

* bpo-15819: Remove redundant include search directory option for
  building outside the source tree.

* bpo-27566: Fix clean target in freeze makefile (patch by Lisa
  Roach)

* bpo-27705: Update message in validate_ucrtbase.py

* bpo-27983: Cause lack of llvm-profdata tool when using clang as
  required for PGO linking to be a configure time error rather than
  make time when --with-optimizations is enabled.  Also improve our
  ability to find the llvm-profdata tool on MacOS and some Linuxes.

* bpo-26307: The profile-opt build now applies PGO to the built-in
  modules.

* bpo-26359: Add the --with-optimizations configure flag.

* bpo-27713: Suppress spurious build warnings when updating
  importlib's bootstrap files. Patch by Xiang Zhang

* bpo-25825: Correct the references to Modules/python.exp and
  ld_so_aix, which are required on AIX.  This updates references to an
  installation path that was changed in 3.2a4, and undoes changed
  references to the build tree that were made in 3.5.0a1.

* bpo-27453: CPP invocation in configure must use CPPFLAGS. Patch by
  Chi Hsuan Yen.

* bpo-27641: The configure script now inserts comments into the
  makefile to prevent the pgen and _freeze_importlib executables from
  being cross-compiled.

* bpo-26662: Set PYTHON_FOR_GEN in configure as the Python program
  to be used for file generation during the build.

* bpo-10910: Avoid C++ compilation errors on FreeBSD and OS X. Also
  update FreedBSD version checks for the original ctype UTF-8
  workaround.

* bpo-28676: Prevent missing 'getentropy' declaration warning on
  macOS. Patch by Gareth Rees.


Python 3.5.2 final
==================

*Release date: 2016-06-26*


核心与内置
----------

* bpo-26930: Update Windows builds to use OpenSSL 1.0.2h.


测试
----

* bpo-26867: Ubuntu's openssl OP_NO_SSLv3 is forced on by default;
  fix test.


IDLE
----

* bpo-27365: Allow non-ascii in idlelib/NEWS.txt - minimal part for
  3.5.2.


Python 3.5.2 release candidate 1
================================

*Release date: 2016-06-12*


核心与内置
----------

* bpo-27066: Fixed SystemError if a custom opener (for open())
  returns a negative number without setting an exception.

* bpo-20041: Fixed TypeError when frame.f_trace is set to None.
  Patch by Xavier de Gaye.

* bpo-26168: Fixed possible refleaks in failing Py_BuildValue() with
  the "N" format unit.

* bpo-26991: Fix possible refleak when creating a function with
  annotations.

* bpo-27039: Fixed bytearray.remove() for values greater than 127.
  Patch by Joe Jevnik.

* bpo-23640: int.from_bytes() no longer bypasses constructors for
  subclasses.

* bpo-26811: gc.get_objects() no longer contains a broken tuple with
  NULL pointer.

* bpo-20120: Use RawConfigParser for .pypirc parsing, removing
  support for interpolation unintentionally added with move to Python
  3. Behavior no longer does any interpolation in .pypirc files,
  matching behavior in Python 2.7 and Setuptools 19.0.

* bpo-26659: Make the builtin slice type support cycle collection.

* bpo-26718: super.__init__ no longer leaks memory if called
  multiple times. NOTE: A direct call of super.__init__ is not
  endorsed!

* bpo-25339: PYTHONIOENCODING now has priority over locale in
  setting the error handler for stdin and stdout.

* bpo-26494: Fixed crash on iterating exhausting iterators. Affected
  classes are generic sequence iterators, iterators of str, bytes,
  bytearray, list, tuple, set, frozenset, dict, OrderedDict,
  corresponding views and os.scandir() iterator.

* bpo-26581: If coding cookie is specified multiple times on a line
  in Python source code file, only the first one is taken to account.

* bpo-26464: Fix str.translate() when string is ASCII and first
  replacements removes character, but next replacement uses a non-
  ASCII character or a string longer than 1 character. Regression
  introduced in Python 3.5.0.

* bpo-22836: Ensure exception reports from PyErr_Display() and
  PyErr_WriteUnraisable() are sensible even when formatting them
  produces secondary errors.  This affects the reports produced by
  sys.__excepthook__() and when __del__() raises an exception.

* bpo-26302: Correct behavior to reject comma as a legal character
  for cookie names.

* bpo-4806: Avoid masking the original TypeError exception when
  using star ("*") unpacking in function calls.  Based on patch by
  Hagen Fürstenau and Daniel Urban.

* bpo-27138: Fix the doc comment for FileFinder.find_spec().

* bpo-26154: Add a new private _PyThreadState_UncheckedGet()
  function to get the current Python thread state, but don't issue a
  fatal error if it is NULL. This new function must be used instead of
  accessing directly the _PyThreadState_Current variable.  The
  variable is no more exposed since Python 3.5.1 to hide the exact
  implementation of atomic C types, to avoid compiler issues.

* bpo-26194: Deque.insert() gave odd results for bounded deques that
  had reached their maximum size.  Now an IndexError will be raised
  when attempting to insert into a full deque.

* bpo-25843: When compiling code, don't merge constants if they are
  equal but have a different types. For example, "f1, f2 = lambda: 1,
  lambda: 1.0" is now correctly compiled to two different functions:
  "f1()" returns "1" ("int") and "f2()" returns "1.0" ("int"), even if
  "1" and "1.0" are equal.

* bpo-22995: [UPDATE] Comment out the one of the pickleability tests
  in _PyObject_GetState() due to regressions observed in Cython-based
  projects.

* bpo-25961: Disallowed null characters in the type name.

* bpo-25973: Fix segfault when an invalid nonlocal statement binds a
  name starting with two underscores.

* bpo-22995: Instances of extension types with a state that aren't
  subclasses of list or dict and haven't implemented any pickle-
  related methods (__reduce__, __reduce_ex__, __getnewargs__,
  __getnewargs_ex__, or __getstate__), can no longer be pickled.
  Including memoryview.

* bpo-20440: Massive replacing unsafe attribute setting code with
  special macro Py_SETREF.

* bpo-25766: Special method __bytes__() now works in str subclasses.

* bpo-25421: __sizeof__ methods of builtin types now use dynamic
  basic size. This allows sys.getsize() to work correctly with their
  subclasses with __slots__ defined.

* bpo-25709: Fixed problem with in-place string concatenation and
  utf-8 cache.

* bpo-27147: Mention **PEP 420** in the importlib docs.

* bpo-24097: Fixed crash in object.__reduce__() if slot name is
  freed inside __getattr__.

* bpo-24731: Fixed crash on converting objects with special methods
  __bytes__, __trunc__, and __float__ returning instances of
  subclasses of bytes, int, and float to subclasses of bytes, int, and
  float correspondingly.

* bpo-26478: Fix semantic bugs when using binary operators with
  dictionary views and tuples.

* bpo-26171: Fix possible integer overflow and heap corruption in
  zipimporter.get_data().

* bpo-25660: Fix TAB key behaviour in REPL with readline.

* bpo-25887: Raise a RuntimeError when a coroutine object is awaited
  more than once.

* bpo-27243: Update the __aiter__ protocol: instead of returning an
  awaitable that resolves to an asynchronous iterator, the
  asynchronous iterator should be returned directly.  Doing the former
  will trigger a PendingDeprecationWarning.


安全
----

* bpo-26556: Update expat to 2.1.1, fixes CVE-2015-1283.

* Fix TLS stripping vulnerability in smtplib, CVE-2016-0772.
  Reported by Team Oststrom


库
--

* bpo-21386: Implement missing IPv4Address.is_global property.  It
  was documented since 07a5610bae9d.  Initial patch by Roger Luethi.

* bpo-20900: distutils register command now decodes HTTP responses
  correctly.  Initial patch by ingrid.

* A new version of typing.py provides several new classes and
  features: @overload outside stubs, Reversible, DefaultDict, Text,
  ContextManager, Type[], NewType(), TYPE_CHECKING, and numerous bug
  fixes (note that some of the new features are not yet implemented in
  mypy or other static analyzers). Also classes for **PEP 492**
  (Awaitable, AsyncIterable, AsyncIterator) have been added (in fact
  they made it into 3.5.1 but were never mentioned).

* bpo-25738: Stop http.server.BaseHTTPRequestHandler.send_error()
  from sending a message body for 205 Reset Content.  Also, don't send
  Content header fields in responses that don't have a body.  Patch by
  Susumu Koshiba.

* bpo-21313: Fix the "platform" module to tolerate when sys.version
  contains truncated build information.


安全
----

* bpo-26839: On Linux, "os.urandom()" now calls "getrandom()" with
  "GRND_NONBLOCK" to fall back on reading "/dev/urandom" if the
  urandom entropy pool is not initialized yet. Patch written by Colm
  Buckley.


库
--

* bpo-27164: In the zlib module, allow decompressing raw Deflate
  streams with a predefined zdict.  Based on patch by Xiang Zhang.

* bpo-24291: Fix wsgiref.simple_server.WSGIRequestHandler to
  completely write data to the client.  Previously it could do partial
  writes and truncate data.  Also, wsgiref.handler.ServerHandler can
  now handle stdout doing partial writes, but this is deprecated.

* bpo-26809: Add "__all__" to "string".  Patch by Emanuel Barry.

* bpo-26373: subprocess.Popen.communicate now correctly ignores
  BrokenPipeError when the child process dies before .communicate() is
  called in more/all circumstances.

* bpo-21776: distutils.upload now correctly handles HTTPError.
  Initial patch by Claudiu Popa.

* bpo-27114: Fix SSLContext._load_windows_store_certs fails with
  PermissionError

* bpo-18383: Avoid creating duplicate filters when using
  filterwarnings and simplefilter. Based on patch by Alex Shkop.

* bpo-27057: Fix os.set_inheritable() on Android, ioctl() is blocked
  by SELinux and fails with EACCESS. The function now falls back to
  fcntl(). Patch written by Michał Bednarski.

* bpo-27014: Fix infinite recursion using typing.py.  Thanks to
  Kalle Tuure!

* bpo-14132: Fix urllib.request redirect handling when the target
  only has a query string.  Original fix by Ján Janech.

* bpo-17214: The "urllib.request" module now percent-encodes non-
  ASCII bytes found in redirect target URLs.  Some servers send
  Location header fields with non-ASCII bytes, but "http.client"
  requires the request target to be ASCII-encodable, otherwise a
  UnicodeEncodeError is raised.  Based on patch by Christian Heimes.

* bpo-26892: Honor debuglevel flag in urllib.request.HTTPHandler.
  Patch contributed by Chi Hsuan Yen.

* bpo-22274: In the subprocess module, allow stderr to be redirected
  to stdout even when stdout is not redirected.  Patch by Akira Li.

* bpo-26807: mock_open 'files' no longer error on readline at end of
  file. Patch from Yolanda Robla.

* bpo-25745: Fixed leaking a userptr in curses panel destructor.

* bpo-26977: Removed unnecessary, and ignored, call to sum of
  squares helper in statistics.pvariance.

* bpo-26881: The modulefinder module now supports extended opcode
  arguments.

* bpo-23815: Fixed crashes related to directly created instances of
  types in _tkinter and curses.panel modules.

* bpo-17765: weakref.ref() no longer silently ignores keyword
  arguments. Patch by Georg Brandl.

* bpo-26873: xmlrpc now raises ResponseError on unsupported type
  tags instead of silently return incorrect result.

* bpo-26711: Fixed the comparison of plistlib.Data with other types.

* bpo-24114: Fix an uninitialized variable in "ctypes.util". The bug
  only occurs on SunOS when the ctypes implementation searches for the
  "crle" program.  Patch by Xiang Zhang.  Tested on SunOS by Kees Bos.

* bpo-26864: In urllib.request, change the proxy bypass host
  checking against no_proxy to be case-insensitive, and to not match
  unrelated host names that happen to have a bypassed hostname as a
  suffix. Patch by Xiang Zhang.

* bpo-26634: recursive_repr() now sets __qualname__ of wrapper.
  Patch by Xiang Zhang.

* bpo-26804: urllib.request will prefer lower_case proxy environment
  variables over UPPER_CASE or Mixed_Case ones. Patch contributed by
  Hans-Peter Jansen.

* bpo-26837: assertSequenceEqual() now correctly outputs non-
  stringified differing items (like bytes in the -b mode).  This
  affects assertListEqual() and assertTupleEqual().

* bpo-26041: Remove "will be removed in Python 3.7" from deprecation
  messages of platform.dist() and platform.linux_distribution(). Patch
  by Kumaripaba Miyurusara Athukorala.

* bpo-26822: itemgetter, attrgetter and methodcaller objects no
  longer silently ignore keyword arguments.

* bpo-26733: Disassembling a class now disassembles class and static
  methods. Patch by Xiang Zhang.

* bpo-26801: Fix error handling in "shutil.get_terminal_size()",
  catch "AttributeError" instead of "NameError". Patch written by
  Emanuel Barry.

* bpo-24838: tarfile's ustar and gnu formats now correctly calculate
  name and link field limits for multibyte character encodings like
  utf-8.


安全
----

* bpo-26657: Fix directory traversal vulnerability with http.server
  on Windows.  This fixes a regression that was introduced in 3.3.4rc1
  and 3.4.0rc1.  Based on patch by Philipp Hagemeister.


库
--

* bpo-26717: Stop encoding Latin-1-ized WSGI paths with UTF-8.
  Patch by Anthony Sottile.

* bpo-26735: Fix "os.urandom()" on Solaris 11.3 and newer when
  reading more than 1,024 bytes: call "getrandom()" multiple times
  with a limit of 1024 bytes per call.

* bpo-16329: Add .webm to mimetypes.types_map.  Patch by Giampaolo
  Rodola'.

* bpo-13952: Add .csv to mimetypes.types_map.  Patch by Geoff
  Wilson.

* bpo-26709: Fixed Y2038 problem in loading binary PLists.

* bpo-23735: Handle terminal resizing with Readline 6.3+ by
  installing our own SIGWINCH handler.  Patch by Eric Price.

* bpo-26586: In http.server, respond with "413 Request header fields
  too large" if there are too many header fields to parse, rather than
  killing the connection and raising an unhandled exception.  Patch by
  Xiang Zhang.

* bpo-22854: Change BufferedReader.writable() and
  BufferedWriter.readable() to always return False.

* bpo-25195: Fix a regression in mock.MagicMock. _Call is a subclass
  of tuple (changeset 3603bae63c13 only works for classes) so we need
  to implement __ne__ ourselves.  Patch by Andrew Plummer.

* bpo-26644: Raise ValueError rather than SystemError when a
  negative length is passed to SSLSocket.recv() or read().

* bpo-23804: Fix SSL recv(0) and read(0) methods to return zero
  bytes instead of up to 1024.

* bpo-26616: Fixed a bug in datetime.astimezone() method.

* bpo-21925: "warnings.formatwarning()" now catches exceptions on
  "linecache.getline(...)" to be able to log "ResourceWarning" emitted
  late during the Python shutdown process.

* bpo-24266: Ctrl+C during Readline history search now cancels the
  search mode when compiled with Readline 7.

* bpo-26560: Avoid potential ValueError in
  BaseHandler.start_response. Initial patch by Peter Inglesby.


安全
----

* bpo-26313: ssl.py _load_windows_store_certs fails if windows cert
  store is empty. Patch by Baji.


库
--

* bpo-26569: Fix "pyclbr.readmodule()" and "pyclbr.readmodule_ex()"
  to support importing packages.

* bpo-26499: Account for remaining Content-Length in
  HTTPResponse.readline() and read1(). Based on patch by Silent Ghost.
  Also document that HTTPResponse now supports these methods.

* bpo-25320: Handle sockets in directories unittest discovery is
  scanning. Patch from Victor van den Elzen.

* bpo-16181: cookiejar.http2time() now returns None if year is
  higher than datetime.MAXYEAR.

* bpo-26513: Fixes platform module detection of Windows Server

* bpo-23718: Fixed parsing time in week 0 before Jan 1.  Original
  patch by Tamás Bence Gedai.

* bpo-20589: Invoking Path.owner() and Path.group() on Windows now
  raise NotImplementedError instead of ImportError.

* bpo-26177: Fixed the keys() method for Canvas and Scrollbar
  widgets.

* bpo-15068: Got rid of excessive buffering in the fileinput module.
  The bufsize parameter is no longer used.

* bpo-2202: Fix UnboundLocalError in
  AbstractDigestAuthHandler.get_algorithm_impls. Initial patch by
  Mathieu Dupuy.

* bpo-25718: Fixed pickling and copying the accumulate() iterator
  with total is None.

* bpo-26475: Fixed debugging output for regular expressions with the
  (?x) flag.

* bpo-26457: Fixed the subnets() methods in IP network classes for
  the case when resulting prefix length is equal to maximal prefix
  length. Based on patch by Xiang Zhang.

* bpo-26385: Remove the file if the internal open() call in
  NamedTemporaryFile() fails. Patch by Silent Ghost.

* bpo-26402: Fix XML-RPC client to retry when the server shuts down
  a persistent connection.  This was a regression related to the new
  http.client.RemoteDisconnected exception in 3.5.0a4.

* bpo-25913: Leading "<~" is optional now in base64.a85decode() with
  adobe=True.  Patch by Swati Jaiswal.

* bpo-26186: Remove an invalid type check in
  importlib.util.LazyLoader.

* bpo-26367: importlib.__import__() raises SystemError like
  builtins.__import__() when "level" is specified but without an
  accompanying package specified.

* bpo-26309: In the "socketserver" module, shut down the request
  (closing the connected socket) when verify_request() returns false.
  Patch by Aviv Palivoda.


安全
----

* bpo-25939: On Windows open the cert store readonly in
  ssl.enum_certificates.


库
--

* bpo-25995: os.walk() no longer uses FDs proportional to the tree
  depth.

* bpo-26117: The os.scandir() iterator now closes file descriptor
  not only when the iteration is finished, but when it was failed with
  error.

* bpo-25911: Restored support of bytes paths in os.walk() on
  Windows.

* bpo-26045: Add UTF-8 suggestion to error message when posting a
  non- Latin-1 string with http.client.

* bpo-12923: Reset FancyURLopener's redirect counter even if there
  is an exception. Based on patches by Brian Brazil and Daniel Rocco.

* bpo-25945: Fixed a crash when unpickle the functools.partial
  object with wrong state. Fixed a leak in failed functools.partial
  constructor. "args" and "keywords" attributes of functools.partial
  have now always types tuple and dict correspondingly.

* bpo-26202: copy.deepcopy() now correctly copies range() objects
  with non-atomic attributes.

* bpo-23076: Path.glob() now raises a ValueError if it's called with
  an invalid pattern. Patch by Thomas Nyberg.

* bpo-19883: Fixed possible integer overflows in zipimport.

* bpo-26227: On Windows, getnameinfo(), gethostbyaddr() and
  gethostbyname_ex() functions of the socket module now decode the
  hostname from the ANSI code page rather than UTF-8.

* bpo-26147: xmlrpc now works with strings not encodable with used
  non-UTF-8 encoding.

* bpo-25935: Garbage collector now breaks reference loops with
  OrderedDict.

* bpo-16620: Fixed AttributeError in msilib.Directory.glob().

* bpo-26013: Added compatibility with broken protocol 2 pickles
  created in old Python 3 versions (3.4.3 and lower).

* bpo-25850: Use cross-compilation by default for 64-bit Windows.

* bpo-17633: Improve zipimport's support for namespace packages.

* bpo-24705: Fix sysconfig._parse_makefile not expanding ${} vars
  appearing before $() vars.

* bpo-22138: Fix mock.patch behavior when patching descriptors.
  Restore original values after patching. Patch contributed by Sean
  McCully.

* bpo-25672: In the ssl module, enable the SSL_MODE_RELEASE_BUFFERS
  mode option if it is safe to do so.

* bpo-26012: Don't traverse into symlinks for "**" pattern in
  pathlib.Path.[r]glob().

* bpo-24120: Ignore PermissionError when traversing a tree with
  pathlib.Path.[r]glob(). Patch by Ulrich Petri.

* bpo-25447: fileinput now uses sys.stdin as-is if it does not have
  a buffer attribute (restores backward compatibility).

* bpo-25447: Copying the lru_cache() wrapper object now always
  works, independently from the type of the wrapped object (by
  returning the original object unchanged).

* bpo-24103: Fixed possible use after free in
  ElementTree.XMLPullParser.

* bpo-25860: os.fwalk() no longer skips remaining directories when
  error occurs. Original patch by Samson Lee.

* bpo-25914: Fixed and simplified OrderedDict.__sizeof__.

* bpo-25902: Fixed various refcount issues in ElementTree iteration.

* bpo-25717: Restore the previous behaviour of tolerating most
  fstat() errors when opening files.  This was a regression in 3.5a1,
  and stopped anonymous temporary files from working in special cases.

* bpo-24903: Fix regression in number of arguments compileall
  accepts when '-d' is specified.  The check on the number of
  arguments has been dropped completely as it never worked correctly
  anyway.

* bpo-25764: In the subprocess module, preserve any exception caused
  by fork() failure when preexec_fn is used.

* bpo-6478: _strptime's regexp cache now is reset after changing
  timezone with time.tzset().

* bpo-14285: When executing a package with the "python -m package"
  option, and package initialization fails, a proper traceback is now
  reported.  The "runpy" module now lets exceptions from package
  initialization pass back to the caller, rather than raising
  ImportError.

* bpo-19771: Also in runpy and the "-m" option, omit the irrelevant
  message ". . . is a package and cannot be directly executed" if the
  package could not even be initialized (e.g. due to a bad "*.pyc"
  file).

* bpo-25177: Fixed problem with the mean of very small and very
  large numbers. As a side effect, statistics.mean and
  statistics.variance should be significantly faster.

* bpo-25718: Fixed copying object with state with boolean value is
  false.

* bpo-10131: Fixed deep copying of minidom documents.  Based on
  patch by Marian Ganisin.

* bpo-25725: Fixed a reference leak in pickle.loads() when
  unpickling invalid data including tuple instructions.

* bpo-25663: In the Readline completer, avoid listing duplicate
  global names, and search the global namespace before searching
  builtins.

* bpo-25688: Fixed file leak in ElementTree.iterparse() raising an
  error.

* bpo-23914: Fixed SystemError raised by unpickler on broken pickle
  data.

* bpo-25691: Fixed crash on deleting ElementTree.Element attributes.

* bpo-25624: ZipFile now always writes a ZIP_STORED header for
  directory entries.  Patch by Dingyuan Wang.

* Skip getaddrinfo if host is already resolved. Patch by A. Jesse
  Jiryu Davis.

* bpo-26050: Add asyncio.StreamReader.readuntil() method. Patch by
  Марк Коренберг.

* bpo-25924: Avoid unnecessary serialization of getaddrinfo(3) calls
  on OS X versions 10.5 or higher.  Original patch by A. Jesse Jiryu
  Davis.

* bpo-26406: Avoid unnecessary serialization of getaddrinfo(3) calls
  on current versions of OpenBSD and NetBSD.  Patch by A. Jesse Jiryu
  Davis.

* bpo-26848: Fix asyncio/subprocess.communicate() to handle empty
  input. Patch by Jack O'Connor.

* bpo-27040: Add loop.get_exception_handler method

* bpo-27041: asyncio: Add loop.create_future method

* bpo-27223: asyncio: Fix _read_ready and _write_ready to respect
  _conn_lost. Patch by Łukasz Langa.

* bpo-22970: asyncio: Fix inconsistency cancelling Condition.wait.
  Patch by David Coles.


IDLE
----

* bpo-5124: Paste with text selected now replaces the selection on
  X11. This matches how paste works on Windows, Mac, most modern Linux
  apps, and ttk widgets. Original patch by Serhiy Storchaka.

* bpo-24759: Make clear in idlelib.idle_test.__init__ that the
  directory is a private implementation of test.test_idle and tool for
  maintainers.

* bpo-27196: Stop 'ThemeChanged' warnings when running IDLE tests.
  These persisted after other warnings were suppressed in #20567.
  Apply Serhiy Storchaka's update_idletasks solution to four test
  files. Record this additional advice in idle_test/README.txt

* bpo-20567: Revise idle_test/README.txt with advice about avoiding
  tk warning messages from tests.  Apply advice to several IDLE tests.

* bpo-27117: Make colorizer htest and turtledemo work with dark
  themes. Move code for configuring text widget colors to a new
  function.

* bpo-26673: When tk reports font size as 0, change to size 10. Such
  fonts on Linux prevented the configuration dialog from opening.

* bpo-21939: Add test for IDLE's percolator. Original patch by
  Saimadhav Heblikar.

* bpo-21676: Add test for IDLE's replace dialog. Original patch by
  Saimadhav Heblikar.

* bpo-18410: Add test for IDLE's search dialog. Original patch by
  Westley Martínez.

* bpo-21703: Add test for IDLE's undo delegator. Original patch by
  Saimadhav Heblikar .

* bpo-27044: Add ConfigDialog.remove_var_callbacks to stop memory
  leaks.

* bpo-23977: Add more asserts to test_delegator.

* bpo-20640: Add tests for idlelib.configHelpSourceEdit. Patch by
  Saimadhav Heblikar.

* In the 'IDLE-console differences' section of the IDLE doc, clarify
  how running with IDLE affects sys.modules and the standard streams.

* bpo-25507: fix incorrect change in IOBinding that prevented
  printing. Augment IOBinding htest to include all major IOBinding
  functions.

* bpo-25905: Revert unwanted conversion of ' to ’ RIGHT SINGLE
  QUOTATION MARK in README.txt and open this and NEWS.txt with
  'ascii'. Re-encode CREDITS.txt to utf-8 and open it with 'utf-8'.


文档
----

* bpo-19489: Moved the search box from the sidebar to the header and
  footer of each page. Patch by Ammar Askar.

* bpo-24136: Document the new **PEP 448** unpacking syntax of 3.5.

* bpo-26736: Used HTTPS for external links in the documentation if
  possible.

* bpo-6953: Rework the Readline module documentation to group
  related functions together, and add more details such as what
  underlying Readline functions and variables are accessed.

* bpo-23606: Adds note to ctypes documentation regarding
  cdll.msvcrt.

* bpo-25500: Fix documentation to not claim that __import__ is
  searched for in the global scope.

* bpo-26014: Update 3.x packaging documentation: * "See also" links
  to the new docs are now provided in the legacy pages * links to
  setuptools documentation have been updated


测试
----

* bpo-21916: Added tests for the turtle module.  Patch by ingrid,
  Gregory Loyse and Jelle Zijlstra.

* bpo-26523: The multiprocessing thread pool
  (multiprocessing.dummy.Pool) was untested.

* bpo-26015: Added new tests for pickling iterators of mutable
  sequences.

* bpo-26325: Added test.support.check_no_resource_warning() to check
  that no ResourceWarning is emitted.

* bpo-25940: Changed test_ssl to use self-signed.pythontest.net.
  This avoids relying on svn.python.org, which recently changed root
  certificate.

* bpo-25616: Tests for OrderedDict are extracted from
  test_collections into separate file test_ordered_dict.

* bpo-26583: Skip test_timestamp_overflow in test_import if bytecode
  files cannot be written.


构建
----

* bpo-26884: Fix linking extension modules for cross builds. Patch
  by Xavier de Gaye.

* bpo-22359: Disable the rules for running _freeze_importlib and
  pgen when cross-compiling.  The output of these programs is normally
  saved with the source code anyway, and is still regenerated when
  doing a native build. Patch by Xavier de Gaye.

* bpo-27229: Fix the cross-compiling pgen rule for in-tree builds.
  Patch by Xavier de Gaye.

* bpo-21668: Link audioop, _datetime, _ctypes_test modules to libm,
  except on Mac OS X. Patch written by Xavier de Gaye.

* bpo-25702: A --with-lto configure option has been added that will
  enable link time optimizations at build time during a make profile-
  opt. Some compilers and toolchains are known to not produce stable
  code when using LTO, be sure to test things thoroughly before
  relying on it. It can provide a few % speed up over profile-opt
  alone.

* bpo-26624: Adds validation of ucrtbase[d].dll version with warning
  for old versions.

* bpo-17603: Avoid error about nonexistent fileblocks.o file by
  using a lower-level check for st_blocks in struct stat.

* bpo-26079: Fixing the build output folder for tix-8.4.3.6. Patch
  by Bjoern Thiel.

* bpo-26465: Update Windows builds to use OpenSSL 1.0.2g.

* bpo-24421: Compile Modules/_math.c once, before building
  extensions. Previously it could fail to compile properly if the math
  and cmath builds were concurrent.

* bpo-25348: Added "--pgo" and "--pgo-job" arguments to
  "PCbuild\build.bat" for building with Profile-Guided Optimization.
  The old "PCbuild\build_pgo.bat" script is now deprecated, and simply
  calls "PCbuild\build.bat --pgo %*".

* bpo-25827: Add support for building with ICC to "configure",
  including a new "--with-icc" flag.

* bpo-25696: Fix installation of Python on UNIX with make -j9.

* bpo-26930: Update OS X 10.5+ 32-bit-only installer to build and
  link with OpenSSL 1.0.2h.

* bpo-26268: Update Windows builds to use OpenSSL 1.0.2f.

* bpo-25136: Support Apple Xcode 7's new textual SDK stub libraries.

* bpo-24324: Do not enable unreachable code warnings when using gcc
  as the option does not work correctly in older versions of gcc and
  has been silently removed as of gcc-4.5.


Windows
-------

* bpo-27053: Updates make_zip.py to correctly generate library ZIP
  file.

* bpo-26268: Update the prepare_ssl.py script to handle OpenSSL
  releases that don't include the contents of the include directory
  (that is, 1.0.2e and later).

* bpo-26071: bdist_wininst created binaries fail to start and find
  32bit Python

* bpo-26073: Update the list of magic numbers in launcher

* bpo-26065: Excludes venv from library when generating embeddable
  distro.


工具/示例
---------

* bpo-26799: Fix python-gdb.py: don't get C types once when the
  Python code is loaded, but get C types on demand. The C types can
  change if python-gdb.py is loaded before the Python executable.
  Patch written by Thomas Ilsche.

* bpo-26271: Fix the Freeze tool to properly use flags passed
  through configure. Patch by Daniel Shaulov.

* bpo-26489: Add dictionary unpacking support to
  Tools/parser/unparse.py. Patch by Guo Ci Teo.

* bpo-26316: Fix variable name typo in Argument Clinic.


Windows
-------

* bpo-17500: Remove unused and outdated icons. (See also:
  https://github.com/python/pythondotorg/issues/945)


Python 3.5.1 final
==================

*Release date: 2015-12-06*


核心与内置
----------

* bpo-25709: Fixed problem with in-place string concatenation and
  utf-8 cache.


Windows
-------

* bpo-25715: Python 3.5.1 installer shows wrong upgrade path and
  incorrect logic for launcher detection.


Python 3.5.1 release candidate 1
================================

*Release date: 2015-11-22*


核心与内置
----------

* bpo-25630: Fix a possible segfault during argument parsing in
  functions that accept filesystem paths.

* bpo-23564: Fixed a partially broken sanity check in the
  _posixsubprocess internals regarding how fds_to_pass were passed to
  the child.  The bug had no actual impact as subprocess.py already
  avoided it.

* bpo-25388: Fixed tokenizer crash when processing undecodable
  source code with a null byte.

* bpo-25462: The hash of the key now is calculated only once in most
  operations in C implementation of OrderedDict.

* bpo-22995: Default implementation of __reduce__ and __reduce_ex__
  now rejects builtin types with not defined __new__.

* bpo-25555: Fix parser and AST: fill lineno and col_offset of "arg"
  node when compiling AST from Python objects.

* bpo-24802: Avoid buffer overreads when int(), float(), compile(),
  exec() and eval() are passed bytes-like objects.  These objects are
  not necessarily terminated by a null byte, but the functions assumed
  they were.

* bpo-24726: Fixed a crash and leaking NULL in repr() of OrderedDict
  that was mutated by direct calls of dict methods.

* bpo-25449: Iterating OrderedDict with keys with unstable hash now
  raises KeyError in C implementations as well as in Python
  implementation.

* bpo-25395: Fixed crash when highly nested OrderedDict structures
  were garbage collected.

* bpo-25274: sys.setrecursionlimit() now raises a RecursionError if
  the new recursion limit is too low depending at the current
  recursion depth. Modify also the "lower-water mark" formula to make
  it monotonic. This mark is used to decide when the overflowed flag
  of the thread state is reset.

* bpo-24402: Fix input() to prompt to the redirected stdout when
  sys.stdout.fileno() fails.

* bpo-24806: Prevent builtin types that are not allowed to be
  subclassed from being subclassed through multiple inheritance.

* bpo-24848: Fixed a number of bugs in UTF-7 decoding of misformed
  data.

* bpo-25280: Import trace messages emitted in verbose (-v) mode are
  no longer formatted twice.

* bpo-25003: On Solaris 11.3 or newer, os.urandom() now uses the
  getrandom() function instead of the getentropy() function. The
  getentropy() function is blocking to generate very good quality
  entropy, os.urandom() doesn't need such high-quality entropy.

* bpo-25182: The stdprinter (used as sys.stderr before the io module
  is imported at startup) now uses the backslashreplace error handler.

* bpo-25131: Make the line number and column offset of set/dict
  literals and comprehensions correspond to the opening brace.

* bpo-25150: Hide the private _Py_atomic_xxx symbols from the public
  Python.h header to fix a compilation error with OpenMP.
  PyThreadState_GET() becomes an alias to PyThreadState_Get() to avoid
  ABI incompatibilities.


库
--

* bpo-25626: Change three zlib functions to accept sizes that fit in
  Py_ssize_t, but internally cap those sizes to UINT_MAX.  This
  resolves a regression in 3.5 where GzipFile.read() failed to read
  chunks larger than 2 or 4 GiB.  The change affects the
  zlib.Decompress.decompress() max_length parameter, the
  zlib.decompress() bufsize parameter, and the zlib.Decompress.flush()
  length parameter.

* bpo-25583: Avoid incorrect errors raised by
  os.makedirs(exist_ok=True) when the OS gives priority to errors such
  as EACCES over EEXIST.

* bpo-25593: Change semantics of EventLoop.stop() in asyncio.

* bpo-6973: When we know a subprocess.Popen process has died, do not
  allow the send_signal(), terminate(), or kill() methods to do
  anything as they could potentially signal a different process.

* bpo-25590: In the Readline completer, only call getattr() once per
  attribute.

* bpo-25498: Fix a crash when garbage-collecting ctypes objects
  created by wrapping a memoryview.  This was a regression made in
  3.5a1.  Based on patch by Eryksun.

* bpo-25584: Added "escape" to the __all__ list in the glob module.

* bpo-25584: Fixed recursive glob() with patterns starting with
  "**".

* bpo-25446: Fix regression in smtplib's AUTH LOGIN support.

* bpo-18010: Fix the pydoc web server's module search function to
  handle exceptions from importing packages.

* bpo-25554: Got rid of circular references in regular expression
  parsing.

* bpo-25510: fileinput.FileInput.readline() now returns b'' instead
  of '' at the end if the FileInput was opened with binary mode. Patch
  by Ryosuke Ito.

* bpo-25503: Fixed inspect.getdoc() for inherited docstrings of
  properties. Original patch by John Mark Vandenberg.

* bpo-25515: Always use os.urandom as a source of randomness in
  uuid.uuid4.

* bpo-21827: Fixed textwrap.dedent() for the case when largest
  common whitespace is a substring of smallest leading whitespace.
  Based on patch by Robert Li.

* bpo-25447: The lru_cache() wrapper objects now can be copied and
  pickled (by returning the original object unchanged).

* bpo-25390: typing: Don't crash on Union[str, Pattern].

* bpo-25441: asyncio: Raise error from drain() when socket is
  closed.

* bpo-25410: Cleaned up and fixed minor bugs in C implementation of
  OrderedDict.

* bpo-25411: Improved Unicode support in SMTPHandler through better
  use of the email package. Thanks to user simon04 for the patch.

* bpo-25407: Remove mentions of the formatter module being removed
  in Python 3.6.

* bpo-25406: Fixed a bug in C implementation of
  OrderedDict.move_to_end() that caused segmentation fault or hang in
  iterating after moving several items to the start of ordered dict.

* bpo-25364: zipfile now works in threads disabled builds.

* bpo-25328: smtpd's SMTPChannel now correctly raises a ValueError
  if both decode_data and enable_SMTPUTF8 are set to true.

* bpo-25316: distutils raises OSError instead of
  DistutilsPlatformError when MSVC is not installed.

* bpo-25380: Fixed protocol for the STACK_GLOBAL opcode in
  pickletools.opcodes.

* bpo-23972: Updates asyncio datagram create method allowing
  reuseport and reuseaddr socket options to be set prior to binding
  the socket. Mirroring the existing asyncio create_server method the
  reuseaddr option for datagram sockets defaults to True if the O/S is
  'posix' (except if the platform is Cygwin). Patch by Chris Laws.

* bpo-25304: Add asyncio.run_coroutine_threadsafe().  This lets you
  submit a coroutine to a loop from another thread, returning a
  concurrent.futures.Future.  By Vincent Michel.

* bpo-25232: Fix CGIRequestHandler to split the query from the URL
  at the first question mark (?) rather than the last. Patch from
  Xiang Zhang.

* bpo-24657: Prevent CGIRequestHandler from collapsing slashes in
  the query part of the URL as if it were a path. Patch from Xiang
  Zhang.

* bpo-24483: C implementation of functools.lru_cache() now
  calculates key's hash only once.

* bpo-22958: Constructor and update method of
  weakref.WeakValueDictionary now accept the self and the dict keyword
  arguments.

* bpo-22609: Constructor of collections.UserDict now accepts the
  self keyword argument.

* bpo-25111: Fixed comparison of traceback.FrameSummary.

* bpo-25262: Added support for BINBYTES8 opcode in Python
  implementation of unpickler. Highest 32 bits of 64-bit size for
  BINUNICODE8 and BINBYTES8 opcodes no longer silently ignored on
  32-bit platforms in C implementation.

* bpo-25034: Fix string.Formatter problem with auto-numbering and
  nested format_specs. Patch by Anthon van der Neut.

* bpo-25233: Rewrite the guts of asyncio.Queue and asyncio.Semaphore
  to be more understandable and correct.

* bpo-25203: Failed readline.set_completer_delims() no longer left
  the module in inconsistent state.

* bpo-23600: Default implementation of tzinfo.fromutc() was
  returning wrong results in some cases.

* bpo-23329: Allow the ssl module to be built with older versions of
  LibreSSL.

* Prevent overflow in _Unpickler_Read.

* bpo-25047: The XML encoding declaration written by Element Tree
  now respects the letter case given by the user. This restores the
  ability to write encoding names in uppercase like "UTF-8", which
  worked in Python 2.

* bpo-25135: Make deque_clear() safer by emptying the deque before
  clearing. This helps avoid possible reentrancy issues.

* bpo-19143: platform module now reads Windows version from
  kernel32.dll to avoid compatibility shims.

* bpo-25092: Fix datetime.strftime() failure when errno was already
  set to EINVAL.

* bpo-23517: Fix rounding in fromtimestamp() and utcfromtimestamp()
  methods of datetime.datetime: microseconds are now rounded to
  nearest with ties going to nearest even integer (ROUND_HALF_EVEN),
  instead of being rounding towards minus infinity (ROUND_FLOOR). It's
  important that these methods use the same rounding mode than
  datetime.timedelta to keep the property: (datetime(1970,1,1) +
  timedelta(seconds=t)) == datetime.utcfromtimestamp(t). It also the
  rounding mode used by round(float) for example.

* bpo-25155: Fix datetime.datetime.now() and
  datetime.datetime.utcnow() on Windows to support date after year
  2038. It was a regression introduced in Python 3.5.0.

* bpo-25108: Omitted internal frames in traceback functions
  print_stack(), format_stack(), and extract_stack() called without
  arguments.

* bpo-25118: Fix a regression of Python 3.5.0 in os.waitpid() on
  Windows.

* bpo-24684: socket.socket.getaddrinfo() now calls
  PyUnicode_AsEncodedString() instead of calling the encode() method
  of the host, to handle correctly custom string with an encode()
  method which doesn't return a byte string. The encoder of the IDNA
  codec is now called directly instead of calling the encode() method
  of the string.

* bpo-25060: Correctly compute stack usage of the BUILD_MAP opcode.

* bpo-24857: Comparing call_args to a long sequence now correctly
  returns a boolean result instead of raising an exception.  Patch by
  A Kaptur.

* bpo-23144: Make sure that HTMLParser.feed() returns all the data,
  even when convert_charrefs is True.

* bpo-24982: shutil.make_archive() with the "zip" format now adds
  entries for directories (including empty directories) in ZIP file.

* bpo-25019: Fixed a crash caused by setting non-string key of expat
  parser. Based on patch by John Leitch.

* bpo-16180: Exit pdb if file has syntax error, instead of trapping
  user in an infinite loop.  Patch by Xavier de Gaye.

* bpo-24891: Fix a race condition at Python startup if the file
  descriptor of stdin (0), stdout (1) or stderr (2) is closed while
  Python is creating sys.stdin, sys.stdout and sys.stderr objects.
  These attributes are now set to None if the creation of the object
  failed, instead of raising an OSError exception. Initial patch
  written by Marco Paolini.

* bpo-24992: Fix error handling and a race condition (related to
  garbage collection) in collections.OrderedDict constructor.

* bpo-24881: Fixed setting binary mode in Python implementation of
  FileIO on Windows and Cygwin.  Patch from Akira Li.

* bpo-25578: Fix (another) memory leak in SSLSocket.getpeercer().

* bpo-25530: Disable the vulnerable SSLv3 protocol by default when
  creating ssl.SSLContext.

* bpo-25569: Fix memory leak in SSLSocket.getpeercert().

* bpo-25471: Sockets returned from accept() shouldn't appear to be
  nonblocking.

* bpo-25319: When threading.Event is reinitialized, the underlying
  condition should use a regular lock rather than a recursive lock.

* bpo-21112: Fix regression in unittest.expectedFailure on
  subclasses. Patch from Berker Peksag.

* bpo-24764: cgi.FieldStorage.read_multi() now ignores the Content-
  Length header in part headers. Patch written by Peter Landry and
  reviewed by Pierre Quentel.

* bpo-24913: Fix overrun error in deque.index(). Found by John
  Leitch and Bryce Darling.

* bpo-24774: Fix docstring in http.server.test. Patch from Chiu-
  Hsiang Hsu.

* bpo-21159: Improve message in
  configparser.InterpolationMissingOptionError. Patch from Łukasz
  Langa.

* bpo-20362: Honour TestCase.longMessage correctly in assertRegex.
  Patch from Ilia Kurenkov.

* bpo-23572: Fixed functools.singledispatch on classes with falsy
  metaclasses.  Patch by Ethan Furman.

* asyncio: ensure_future() now accepts awaitable objects.


IDLE
----

* bpo-15348: Stop the debugger engine (normally in a user process)
  before closing the debugger window (running in the IDLE process).
  This prevents the RuntimeErrors that were being caught and ignored.

* bpo-24455: Prevent IDLE from hanging when a) closing the shell
  while the debugger is active (15347); b) closing the debugger with
  the [X] button (15348); and c) activating the debugger when already
  active (24455). The patch by Mark Roseman does this by making two
  changes. 1. Suspend and resume the gui.interaction method with the
  tcl vwait mechanism intended for this purpose (instead of
  root.mainloop & .quit). 2. In gui.run, allow any existing
  interaction to terminate first.

* Change 'The program' to 'Your program' in an IDLE 'kill program?'
  message to make it clearer that the program referred to is the
  currently running user program, not IDLE itself.

* bpo-24750: Improve the appearance of the IDLE editor window status
  bar. Patch by Mark Roseman.

* bpo-25313: Change the handling of new built-in text color themes
  to better address the compatibility problem introduced by the
  addition of IDLE Dark. Consistently use the revised
  idleConf.CurrentTheme everywhere in idlelib.

* bpo-24782: Extension configuration is now a tab in the IDLE
  Preferences dialog rather than a separate dialog.  The former tabs
  are now a sorted list.  Patch by Mark Roseman.

* bpo-22726: Re-activate the config dialog help button with some
  content about the other buttons and the new IDLE Dark theme.

* bpo-24820: IDLE now has an 'IDLE Dark' built-in text color theme.
  It is more or less IDLE Classic inverted, with a cobalt blue
  background. Strings, comments, keywords, ... are still green, red,
  orange, ... . To use it with IDLEs released before November 2015,
  hit the 'Save as New Custom Theme' button and enter a new name, such
  as 'Custom Dark'.  The custom theme will work with any IDLE release,
  and can be modified.

* bpo-25224: README.txt is now an idlelib index for IDLE developers
  and curious users. The previous user content is now in the IDLE doc
  chapter. 'IDLE' now means 'Integrated Development and Learning
  Environment'.

* bpo-24820: Users can now set breakpoint colors in Settings ->
  Custom Highlighting. Original patch by Mark Roseman.

* bpo-24972: Inactive selection background now matches active
  selection background, as configured by users, on all systems.  Found
  items are now always highlighted on Windows.  Initial patch by Mark
  Roseman.

* bpo-24570: Idle: make calltip and completion boxes appear on Macs
  affected by a tk regression.  Initial patch by Mark Roseman.

* bpo-24988: Idle ScrolledList context menus (used in debugger) now
  work on Mac Aqua. Patch by Mark Roseman.

* bpo-24801: Make right-click for context menu work on Mac Aqua.
  Patch by Mark Roseman.

* bpo-25173: Associate tkinter messageboxes with a specific widget.
  For Mac OSX, make them a 'sheet'.  Patch by Mark Roseman.

* bpo-25198: Enhance the initial html viewer now used for Idle Help.
  Properly indent fixed-pitch text (patch by Mark Roseman). Give code
  snippet a very Sphinx-like light blueish-gray background. Re-use
  initial width and height set by users for shell and editor. When the
  Table of Contents (TOC) menu is used, put the section header at the
  top of the screen.

* bpo-25225: Condense and rewrite Idle doc section on text colors.

* bpo-21995: Explain some differences between IDLE and console
  Python.

* bpo-22820: Explain need for *print* when running file from Idle
  editor.

* bpo-25224: Doc: augment Idle feature list and no-subprocess
  section.

* bpo-25219: Update doc for Idle command line options. Some were
  missing and notes were not correct.

* bpo-24861: Most of idlelib is private and subject to change. Use
  idleib.idle.* to start Idle. See idlelib.__init__.__doc__.

* bpo-25199: Idle: add synchronization comments for future
  maintainers.

* bpo-16893: Replace help.txt with help.html for Idle doc display.
  The new idlelib/help.html is rstripped
  Doc/build/html/library/idle.html. It looks better than help.txt and
  will better document Idle as released. The tkinter html viewer that
  works for this file was written by Mark Roseman. The now unused
  EditorWindow.HelpDialog class and helt.txt file are deprecated.

* bpo-24199: Deprecate unused idlelib.idlever with possible removal
  in 3.6.

* bpo-24790: Remove extraneous code (which also create 2 & 3
  conflicts).


文档
----

* bpo-22558: Add remaining doc links to source code for Python-coded
  modules. Patch by Yoni Lavi.

* bpo-12067: Rewrite Comparisons section in the Expressions chapter
  of the language reference. Some of the details of comparing mixed
  types were incorrect or ambiguous. NotImplemented is only relevant
  at a lower level than the Expressions chapter. Added details of
  comparing range() objects, and default behaviour and consistency
  suggestions for user-defined classes. Patch from Andy Maier.

* bpo-24952: Clarify the default size argument of stack_size() in
  the "threading" and "_thread" modules. Patch from Mattip.

* bpo-23725: Overhaul tempfile docs. Note deprecated status of
  mktemp. Patch from Zbigniew Jędrzejewski-Szmek.

* bpo-24808: Update the types of some PyTypeObject fields.  Patch by
  Joseph Weston.

* bpo-22812: Fix unittest discovery examples. Patch from Pam
  McA'Nulty.


测试
----

* bpo-25449: Added tests for OrderedDict subclasses.

* bpo-25099: Make test_compileall not fail when an entry on sys.path
  cannot be written to (commonly seen in administrative installs on
  Windows).

* bpo-23919: Prevents assert dialogs appearing in the test suite.

* "PCbuild\rt.bat" now accepts an unlimited number of arguments to
  pass along to regrtest.py.  Previously there was a limit of 9.


构建
----

* bpo-24915: Add LLVM support for PGO builds and use the test suite
  to generate the profile data. Initial patch by Alecsandru Patrascu
  of Intel.

* bpo-24910: Windows MSIs now have unique display names.

* bpo-24986: It is now possible to build Python on Windows without
  errors when external libraries are not available.


Windows
-------

* bpo-25450: Updates shortcuts to start Python in installation
  directory.

* bpo-25164: Changes default all-users install directory to match
  per- user directory.

* bpo-25143: Improves installer error messages for unsupported
  platforms.

* bpo-25163: Display correct directory in installer when using non-
  default settings.

* bpo-25361: Disables use of SSE2 instructions in Windows 32-bit
  build

* bpo-25089: Adds logging to installer for case where launcher is
  not selected on upgrade.

* bpo-25165: Windows uninstallation should not remove launcher if
  other versions remain

* bpo-25112: py.exe launcher is missing icons

* bpo-25102: Windows installer does not precompile for -O or -OO.

* bpo-25081: Makes Back button in installer go back to upgrade page
  when upgrading.

* bpo-25091: Increases font size of the installer.

* bpo-25126: Clarifies that the non-web installer will download some
  components.

* bpo-25213: Restores requestedExecutionLevel to manifest to disable
  UAC virtualization.

* bpo-25022: Removed very outdated PC/example_nt/ directory.


工具/示例
---------

* bpo-25440: Fix output of python-config --extension-suffix.


Python 3.5.0 final
==================

*Release date: 2015-09-13*


构建
----

* bpo-25071: Windows installer should not require TargetDir
  parameter when installing quietly.


Python 3.5.0 release candidate 4
================================

*Release date: 2015-09-09*


库
--

* bpo-25029: Fixes MemoryError in test_strptime.


构建
----

* bpo-25027: Reverts partial-static build options and adds
  vcruntime140.dll to Windows installation.


Python 3.5.0 release candidate 3
================================

*Release date: 2015-09-07*


核心与内置
----------

* bpo-24305: Prevent import subsystem stack frames from being
  counted by the warnings.warn(stacklevel=) parameter.

* bpo-24912: Prevent __class__ assignment to immutable built-in
  objects.

* bpo-24975: Fix AST compilation for **PEP 448** syntax.


库
--

* bpo-24917: time_strftime() buffer over-read.

* bpo-24748: To resolve a compatibility problem found with py2exe
  and pywin32, imp.load_dynamic() once again ignores previously loaded
  modules to support Python modules replacing themselves with
  extension modules. Patch by Petr Viktorin.

* bpo-24635: Fixed a bug in typing.py where isinstance([],
  typing.Iterable) would return True once, then False on subsequent
  calls.

* bpo-24989: Fixed buffer overread in BytesIO.readline() if a
  position is set beyond size.  Based on patch by John Leitch.

* bpo-24913: Fix overrun error in deque.index(). Found by John
  Leitch and Bryce Darling.


Python 3.5.0 release candidate 2
================================

*Release date: 2015-08-25*


核心与内置
----------

* bpo-24769: Interpreter now starts properly when dynamic loading is
  disabled.  Patch by Petr Viktorin.

* bpo-21167: NAN operations are now handled correctly when python is
  compiled with ICC even if -fp-model strict is not specified.

* bpo-24492: A "package" lacking a __name__ attribute when trying to
  perform a "from .. import ..." statement will trigger an ImportError
  instead of an AttributeError.


库
--

* bpo-24847: Removes vcruntime140.dll dependency from Tcl/Tk.

* bpo-24839: platform._syscmd_ver raises DeprecationWarning

* bpo-24867: Fix Task.get_stack() for 'async def' coroutines


Python 3.5.0 release candidate 1
================================

*Release date: 2015-08-09*


核心与内置
----------

* bpo-24667: Resize odict in all cases that the underlying dict
  resizes.


库
--

* bpo-24824: Signatures of codecs.encode() and codecs.decode() now
  are compatible with pydoc.

* bpo-24634: Importing uuid should not try to load libc on Windows

* bpo-24798: _msvccompiler.py doesn't properly support manifests

* bpo-4395: Better testing and documentation of binary operators.
  Patch by Martin Panter.

* bpo-23973: Update typing.py from GitHub repo.

* bpo-23004: mock_open() now reads binary data correctly when the
  type of read_data is bytes.  Initial patch by Aaron Hill.

* bpo-23888: Handle fractional time in cookie expiry. Patch by ssh.

* bpo-23652: Make it possible to compile the select module against
  the libc headers from the Linux Standard Base, which do not include
  some EPOLL macros.  Patch by Matt Frank.

* bpo-22932: Fix timezones in email.utils.formatdate. Patch from
  Dmitry Shachnev.

* bpo-23779: imaplib raises TypeError if authenticator tries to
  abort. Patch from Craig Holmquist.

* bpo-23319: Fix ctypes.BigEndianStructure, swap correctly bytes.
  Patch written by Matthieu Gautier.

* bpo-23254: Document how to close the TCPServer listening socket.
  Patch from Martin Panter.

* bpo-19450: Update Windows and OS X installer builds to use SQLite
  3.8.11.

* bpo-17527: Add PATCH to wsgiref.validator. Patch from Luca
  Sbardella.

* bpo-24791: Fix grammar regression for call syntax: 'g(*a or b)'.


IDLE
----

* bpo-23672: Allow Idle to edit and run files with astral chars in
  name. Patch by Mohd Sanad Zaki Rizvi.

* bpo-24745: Idle editor default font. Switch from Courier to
  platform-sensitive TkFixedFont.  This should not affect current
  customized font selections.  If there is a problem, edit
  $HOME/.idlerc/config-main.cfg and remove 'fontxxx' entries from
  [Editor Window].  Patch by Mark Roseman.

* bpo-21192: Idle editor. When a file is run, put its name in the
  restart bar. Do not print false prompts. Original patch by Adnan
  Umer.

* bpo-13884: Idle menus. Remove tearoff lines. Patch by Roger Serwy.


文档
----

* bpo-24129: Clarify the reference documentation for name
  resolution. This includes removing the assumption that readers will
  be familiar with the name resolution scheme Python used prior to the
  introduction of lexical scoping for function namespaces. Patch by
  Ivan Levkivskyi.

* bpo-20769: Improve reload() docs. Patch by Dorian Pula.

* bpo-23589: Remove duplicate sentence from the FAQ.  Patch by
  Yongzhi Pan.

* bpo-24729: Correct IO tutorial to match implementation regarding
  encoding parameter to open function.


测试
----

* bpo-24751: When running regrtest with the "-w" command line
  option, a test run is no longer marked as a failure if all tests
  succeed when re-run.


Python 3.5.0 beta 4
===================

*Release date: 2015-07-26*


核心与内置
----------

* bpo-23573: Restored optimization of bytes.rfind() and
  bytearray.rfind() for single-byte argument on Linux.

* bpo-24569: Make **PEP 448** dictionary evaluation more consistent.

* bpo-24583: Fix crash when set is mutated while being updated.

* bpo-24407: Fix crash when dict is mutated while being updated.

* bpo-24619: New approach for tokenizing async/await. As a
  consequence, it is now possible to have one-line 'async def foo():
  await ..' functions.

* bpo-24687: Plug refleak on SyntaxError in function parameters
  annotations.

* bpo-15944: memoryview: Allow arbitrary formats when casting to
  bytes. Patch by Martin Panter.


库
--

* bpo-23441: rcompleter now prints a tab character instead of
  displaying possible completions for an empty word.  Initial patch by
  Martin Sekera.

* bpo-24683: Fixed crashes in _json functions called with arguments
  of inappropriate type.

* bpo-21697: shutil.copytree() now correctly handles symbolic links
  that point to directories.  Patch by Eduardo Seabra and Thomas
  Kluyver.

* bpo-14373: Fixed segmentation fault when gc.collect() is called
  during constructing lru_cache (C implementation).

* bpo-24695: Fix a regression in traceback.print_exception().  If
  exc_traceback is None we shouldn't print a traceback header like
  described in the documentation.

* bpo-24620: Random.setstate() now validates the value of state last
  element.

* bpo-22485: Fixed an issue that caused "inspect.getsource" to
  return incorrect results on nested functions.

* bpo-22153: Improve unittest docs. Patch from Martin Panter and
  evilzero.

* bpo-24580: Symbolic group references to open group in re patterns
  now are explicitly forbidden as well as numeric group references.

* bpo-24206: Fixed __eq__ and __ne__ methods of inspect classes.

* bpo-24631: Fixed regression in the timeit module with multiline
  setup.

* bpo-18622: unittest.mock.mock_open().reset_mock would recurse
  infinitely. Patch from Nicola Palumbo and Laurent De Buyst.

* bpo-23661: unittest.mock side_effects can now be exceptions again.
  This was a regression vs Python 3.4. Patch from Ignacio Rossi

* bpo-24608: chunk.Chunk.read() now always returns bytes, not str.

* bpo-18684: Fixed reading out of the buffer in the re module.

* bpo-24259: tarfile now raises a ReadError if an archive is
  truncated inside a data segment.

* bpo-15014: SMTP.auth() and SMTP.login() now support RFC 4954's
  optional initial-response argument to the SMTP AUTH command.

* bpo-24669: Fix inspect.getsource() for 'async def' functions.
  Patch by Kai Groner.

* bpo-24688: ast.get_docstring() for 'async def' functions.


构建
----

* bpo-24603: Update Windows builds and OS X 10.5 installer to use
  OpenSSL 1.0.2d.


Python 3.5.0 beta 3
===================

*Release date: 2015-07-05*


核心与内置
----------

* bpo-24467: Fixed possible buffer over-read in bytearray. The
  bytearray object now always allocates place for trailing null byte
  and it's buffer now is always null-terminated.

* Upgrade to Unicode 8.0.0.

* bpo-24345: Add Py_tp_finalize slot for the stable ABI.

* bpo-24400: Introduce a distinct type for **PEP 492** coroutines;
  add types.CoroutineType, inspect.getcoroutinestate,
  inspect.getcoroutinelocals; coroutines no longer use CO_GENERATOR
  flag; sys.set_coroutine_wrapper works only for 'async def'
  coroutines; inspect.iscoroutine no longer uses
  collections.abc.Coroutine, it's intended to test for pure 'async
  def' coroutines only; add new opcode: GET_YIELD_FROM_ITER; fix
  generators wrapper used in types.coroutine to be instance of
  collections.abc.Generator; collections.abc.Awaitable and
  collections.abc.Coroutine can no longer be used to detect generator-
  based coroutines--use inspect.isawaitable instead.

* bpo-24450: Add gi_yieldfrom to generators and cr_await to
  coroutines. Contributed by Benno Leslie and Yury Selivanov.

* bpo-19235: Add new RecursionError exception. Patch by Georg
  Brandl.


库
--

* bpo-21750: mock_open.read_data can now be read from each instance,
  as it could in Python 3.3.

* bpo-24552: Fix use after free in an error case of the _pickle
  module.

* bpo-24514: tarfile now tolerates number fields consisting of only
  whitespace.

* bpo-19176: Fixed doctype() related bugs in C implementation of
  ElementTree. A deprecation warning no longer issued by XMLParser
  subclass with default doctype() method.  Direct call of doctype()
  now issues a warning.  Parser's doctype() now is not called if
  target's doctype() is called.  Based on patch by Martin Panter.

* bpo-20387: Restore semantic round-trip correctness in
  tokenize/untokenize for tab-indented blocks.

* bpo-24456: Fixed possible buffer over-read in adpcm2lin() and
  lin2adpcm() functions of the audioop module.

* bpo-24336: The contextmanager decorator now works with functions
  with keyword arguments called "func" and "self".  Patch by Martin
  Panter.

* bpo-24522: Fix possible integer overflow in json accelerator
  module.

* bpo-24489: ensure a previously set C errno doesn't disturb
  cmath.polar().

* bpo-24408: Fixed AttributeError in measure() and metrics() methods
  of tkinter.Font.

* bpo-14373: C implementation of functools.lru_cache() now can be
  used with methods.

* bpo-24347: Set KeyError if PyDict_GetItemWithError returns NULL.

* bpo-24348: Drop superfluous incref/decref.

* bpo-24359: Check for changed OrderedDict size during iteration.

* bpo-24368: Support keyword arguments in OrderedDict methods.

* bpo-24362: Simplify the C OrderedDict fast nodes resize logic.

* bpo-24377: Fix a ref leak in OrderedDict.__repr__.

* bpo-24369: Defend against key-changes during iteration.


测试
----

* bpo-24373: _testmultiphase and xxlimited now use tp_traverse and
  tp_finalize to avoid reference leaks encountered when combining
  tp_dealloc with PyType_FromSpec (see bpo-16690 for details)


文档
----

* bpo-24458: Update documentation to cover multi-phase
  initialization for extension modules (PEP 489). Patch by Petr
  Viktorin.

* bpo-24351: Clarify what is meant by "identifier" in the context of
  string.Template instances.


构建
----

* bpo-24432: Update Windows builds and OS X 10.5 installer to use
  OpenSSL 1.0.2c.


Python 3.5.0 beta 2
===================

*Release date: 2015-05-31*


核心与内置
----------

* bpo-24284: The startswith and endswith methods of the str class no
  longer return True when finding the empty string and the indexes are
  completely out of range.

* bpo-24115: Update uses of PyObject_IsTrue(), PyObject_Not(),
  PyObject_IsInstance(), PyObject_RichCompareBool() and
  _PyDict_Contains() to check for and handle errors correctly.

* bpo-24328: Fix importing one character extension modules.

* bpo-11205: In dictionary displays, evaluate the key before the
  value.

* bpo-24285: Fixed regression that prevented importing extension
  modules from inside packages. Patch by Petr Viktorin.


库
--

* bpo-23247: Fix a crash in the StreamWriter.reset() of CJK codecs.

* bpo-24270: Add math.isclose() and cmath.isclose() functions as per
  **PEP 485**. Contributed by Chris Barker and Tal Einat.

* bpo-5633: Fixed timeit when the statement is a string and the
  setup is not.

* bpo-24326: Fixed audioop.ratecv() with non-default weightB
  argument. Original patch by David Moore.

* bpo-16991: Add a C implementation of OrderedDict.

* bpo-23934: Fix inspect.signature to fail correctly for builtin
  types lacking signature information.  Initial patch by James Powell.


Python 3.5.0 beta 1
===================

*Release date: 2015-05-24*


核心与内置
----------

* bpo-24276: Fixed optimization of property descriptor getter.

* bpo-24268: PEP 489: Multi-phase extension module initialization.
  Patch by Petr Viktorin.

* bpo-23955: Add pyvenv.cfg option to suppress registry/environment
  lookup for generating sys.path on Windows.

* bpo-24257: Fixed system error in the comparison of faked
  types.SimpleNamespace.

* bpo-22939: Fixed integer overflow in iterator object.  Patch by
  Clement Rouault.

* bpo-23985: Fix a possible buffer overrun when deleting a slice
  from the front of a bytearray and then appending some other bytes
  data.

* bpo-24102: Fixed exception type checking in standard error
  handlers.

* bpo-15027: The UTF-32 encoder is now 3x to 7x faster.

* bpo-23290: Optimize set_merge() for cases where the target is
  empty. (Contributed by Serhiy Storchaka.)

* bpo-2292: PEP 448: Additional Unpacking Generalizations.

* bpo-24096: Make warnings.warn_explicit more robust against
  mutation of the warnings.filters list.

* bpo-23996: Avoid a crash when a delegated generator raises an
  unnormalized StopIteration exception.  Patch by Stefan Behnel.

* bpo-23910: Optimize property() getter calls.  Patch by Joe Jevnik.

* bpo-23911: Move path-based importlib bootstrap code to a separate
  frozen module.

* bpo-24192: Fix namespace package imports.

* bpo-24022: Fix tokenizer crash when processing undecodable source
  code.

* bpo-9951: Added a hex() method to bytes, bytearray, and
  memoryview.

* bpo-22906: PEP 479: Change StopIteration handling inside
  generators.

* bpo-24017: PEP 492: Coroutines with async and await syntax.


库
--

* bpo-14373: Added C implementation of functools.lru_cache().  Based
  on patches by Matt Joiner and Alexey Kachayev.

* bpo-24230: The tempfile module now accepts bytes for prefix,
  suffix and dir parameters and returns bytes in such situations
  (matching the os module APIs).

* bpo-22189: collections.UserString now supports __getnewargs__(),
  __rmod__(), casefold(), format_map(), isprintable(), and
  maketrans(). Patch by Joe Jevnik.

* bpo-24244: Prevents termination when an invalid format string is
  encountered on Windows in strftime.

* bpo-23973: PEP 484: Add the typing module.

* bpo-23086: The collections.abc.Sequence() abstract base class
  added *start* and *stop* parameters to the index() mixin. Patch by
  Devin Jeanpierre.

* bpo-20035: Replaced the "tkinter._fix" module used for setting up
  the Tcl/Tk environment on Windows with a private function in the
  "_tkinter" module that makes no permanent changes to the
  environment.

* bpo-24257: Fixed segmentation fault in sqlite3.Row constructor
  with faked cursor type.

* bpo-15836: assertRaises(), assertRaisesRegex(), assertWarns() and
  assertWarnsRegex() assertments now check the type of the first
  argument to prevent possible user error.  Based on patch by Daniel
  Wagner-Hall.

* bpo-9858: Add missing method stubs to _io.RawIOBase.  Patch by
  Laura Rupprecht.

* bpo-22955: attrgetter, itemgetter and methodcaller objects in the
  operator module now support pickling.  Added readable and evaluable
  repr for these objects. Based on patch by Josh Rosenberg.

* bpo-22107: tempfile.gettempdir() and tempfile.mkdtemp() now try
  again when a directory with the chosen name already exists on
  Windows as well as on Unix. tempfile.mkstemp() now fails early if
  parent directory is not valid (not exists or is a file) on Windows.

* bpo-23780: Improved error message in os.path.join() with single
  argument.

* bpo-6598: Increased time precision and random number range in
  email.utils.make_msgid() to strengthen the uniqueness of the message
  ID.

* bpo-24091: Fixed various crashes in corner cases in C
  implementation of ElementTree.

* bpo-21931: msilib.FCICreate() now raises TypeError in the case of
  a bad argument instead of a ValueError with a bogus FCI error
  number. Patch by Jeffrey Armstrong.

* bpo-13866: *quote_via* argument added to urllib.parse.urlencode.

* bpo-20098: New mangle_from policy option for email, default True
  for compat32, but False for all other policies.

* bpo-24211: The email library now supports RFC 6532: it can
  generate headers using utf-8 instead of encoded words.

* bpo-16314: Added support for the LZMA compression in distutils.

* bpo-21804: poplib now supports RFC 6856 (UTF8).

* bpo-18682: Optimized pprint functions for builtin scalar types.

* bpo-22027: smtplib now supports RFC 6531 (SMTPUTF8).

* bpo-23488: Random generator objects now consume 2x less memory on
  64-bit.

* bpo-1322: platform.dist() and platform.linux_distribution()
  functions are now deprecated.  Initial patch by Vajrasky Kok.

* bpo-22486: Added the math.gcd() function.  The fractions.gcd()
  function now is deprecated.  Based on patch by Mark Dickinson.

* bpo-24064: Property() docstrings are now writeable. (Patch by
  Berker Peksag.)

* bpo-22681: Added support for the koi8_t encoding.

* bpo-22682: Added support for the kz1048 encoding.

* bpo-23796: peek and read1 methods of BufferedReader now raise
  ValueError if they called on a closed object. Patch by John
  Hergenroeder.

* bpo-21795: smtpd now supports the 8BITMIME extension whenever the
  new *decode_data* constructor argument is set to False.

* bpo-24155: optimize heapq.heapify() for better cache performance
  when heapifying large lists.

* bpo-21800: imaplib now supports RFC 5161 (enable), RFC 6855
  (utf8/internationalized email) and automatically encodes non-ASCII
  usernames and passwords to UTF8.

* bpo-20274: When calling a _sqlite.Connection, it now complains if
  passed any keyword arguments.  Previously it silently ignored them.

* bpo-20274: Remove ignored and erroneous "kwargs" parameters from
  three METH_VARARGS methods on _sqlite.Connection.

* bpo-24134: assertRaises(), assertRaisesRegex(), assertWarns() and
  assertWarnsRegex() checks now emits a deprecation warning when
  callable is None or keyword arguments except msg is passed in the
  context manager mode.

* bpo-24018: Add a collections.abc.Generator abstract base class.
  Contributed by Stefan Behnel.

* bpo-23880: Tkinter's getint() and getdouble() now support Tcl_Obj.
  Tkinter's getdouble() now supports any numbers (in particular int).

* bpo-22619: Added negative limit support in the traceback module.
  Based on patch by Dmitry Kazakov.

* bpo-24094: Fix possible crash in json.encode with poorly behaved
  dict subclasses.

* bpo-9246: On POSIX, os.getcwd() now supports paths longer than
  1025 bytes. Patch written by William Orr.

* bpo-17445: add difflib.diff_bytes() to support comparison of byte
  strings (fixes a regression from Python 2).

* bpo-23917: Fall back to sequential compilation when
  ProcessPoolExecutor doesn't exist. Patch by Claudiu Popa.

* bpo-23008: Fixed resolving attributes with boolean value is False
  in pydoc.

* Fix asyncio issue 235: LifoQueue and PriorityQueue's put didn't
  increment unfinished tasks (this bug was introduced when
  JoinableQueue was merged with Queue).

* bpo-23908: os functions now reject paths with embedded null
  character on Windows instead of silently truncating them.

* bpo-23728: binascii.crc_hqx() could return an integer outside of
  the range 0-0xffff for empty data.

* bpo-23887: urllib.error.HTTPError now has a proper repr()
  representation. Patch by Berker Peksag.

* asyncio: New event loop APIs: set_task_factory() and
  get_task_factory().

* asyncio: async() function is deprecated in favour of
  ensure_future().

* bpo-24178: asyncio.Lock, Condition, Semaphore, and
  BoundedSemaphore support new 'async with' syntax.  Contributed by
  Yury Selivanov.

* bpo-24179: Support 'async for' for asyncio.StreamReader.
  Contributed by Yury Selivanov.

* bpo-24184: Add AsyncIterator and AsyncIterable ABCs to
  collections.abc. Contributed by Yury Selivanov.

* bpo-22547: Implement informative __repr__ for
  inspect.BoundArguments. Contributed by Yury Selivanov.

* bpo-24190: Implement inspect.BoundArgument.apply_defaults()
  method. Contributed by Yury Selivanov.

* bpo-20691: Add 'follow_wrapped' argument to
  inspect.Signature.from_callable() and inspect.signature().
  Contributed by Yury Selivanov.

* bpo-24248: Deprecate inspect.Signature.from_function() and
  inspect.Signature.from_builtin().

* bpo-23898: Fix inspect.classify_class_attrs() to support
  attributes with overloaded __eq__ and __bool__.  Patch by Mike
  Bayer.

* bpo-24298: Fix inspect.signature() to correctly unwrap wrappers
  around bound methods.


IDLE
----

* bpo-23184: remove unused names and imports in idlelib. Initial
  patch by Al Sweigart.


测试
----

* bpo-21520: test_zipfile no longer fails if the word 'bad' appears
  anywhere in the name of the current directory.

* bpo-9517: Move script_helper into the support package. Patch by
  Christie Wilson.


文档
----

* bpo-22155: Add File Handlers subsection with createfilehandler to
  tkinter doc.  Remove obsolete example from FAQ.  Patch by Martin
  Panter.

* bpo-24029: Document the name binding behavior for submodule
  imports.

* bpo-24077: Fix typo in man page for -I command option: -s, not -S


工具/示例
---------

* bpo-24000: Improved Argument Clinic's mapping of converters to
  legacy "format units". Updated the documentation to match.

* bpo-24001: Argument Clinic converters now use accept={type}
  instead of types={'type'} to specify the types the converter
  accepts.

* bpo-23330: h2py now supports arbitrary filenames in #include.

* bpo-24031: make patchcheck now supports git checkouts, too.


Python 3.5.0 alpha 4
====================

*Release date: 2015-04-19*


核心与内置
----------

* bpo-22980: Under Linux, GNU/KFreeBSD and the Hurd, C extensions
  now include the architecture triplet in the extension name, to make
  it easy to test builds for different ABIs in the same working tree.
  Under OS X, the extension name now includes **PEP 3149**-style
  information.

* bpo-22631: Added Linux-specific socket constant CAN_RAW_FD_FRAMES.
  Patch courtesy of Joe Jevnik.

* bpo-23731: Implement **PEP 488**: removal of .pyo files.

* bpo-23726: Don't enable GC for user subclasses of non-GC types
  that don't add any new fields.  Patch by Eugene Toder.

* bpo-23309: Avoid a deadlock at shutdown if a daemon thread is
  aborted while it is holding a lock to a buffered I/O object, and the
  main thread tries to use the same I/O object (typically stdout or
  stderr).  A fatal error is emitted instead.

* bpo-22977: Fixed formatting Windows error messages on Wine. Patch
  by Martin Panter.

* bpo-23466: %c, %o, %x, and %X in bytes formatting now raise
  TypeError on non-integer input.

* bpo-24044: Fix possible null pointer dereference in list.sort in
  out of memory conditions.

* bpo-21354: PyCFunction_New function is exposed by python DLL
  again.


库
--

* bpo-23840: tokenize.open() now closes the temporary binary file on
  error to fix a resource warning.

* bpo-16914: new debuglevel 2 in smtplib adds timestamps to debug
  output.

* bpo-7159: urllib.request now supports sending auth credentials
  automatically after the first 401.  This enhancement is a superset
  of the enhancement from bpo-19494 and supersedes that change.

* bpo-23703: Fix a regression in urljoin() introduced in
  901e4e52b20a. Patch by Demian Brecht.

* bpo-4254: Adds _curses.update_lines_cols().  Patch by Arnon Yaari

* bpo-19933: Provide default argument for ndigits in round. Patch by
  Vajrasky Kok.

* bpo-23193: Add a numeric_owner parameter to
  tarfile.TarFile.extract and tarfile.TarFile.extractall. Patch by
  Michael Vogt and Eric Smith.

* bpo-23342: Add a subprocess.run() function than returns a
  CalledProcess instance for a more consistent API than the existing
  call* functions.

* bpo-21217: inspect.getsourcelines() now tries to compute the start
  and end lines from the code object, fixing an issue when a lambda
  function is used as decorator argument. Patch by Thomas Ballinger
  and Allison Kaptur.

* bpo-24521: Fix possible integer overflows in the pickle module.

* bpo-22931: Allow '[' and ']' in cookie values.

* The keywords attribute of functools.partial is now always a
  dictionary.

* bpo-23811: Add missing newline to the PyCompileError error
  message. Patch by Alex Shkop.

* bpo-21116: Avoid blowing memory when allocating a multiprocessing
  shared array that's larger than 50% of the available RAM.  Patch by
  Médéric Boquien.

* bpo-22982: Improve BOM handling when seeking to multiple positions
  of a writable text file.

* bpo-23464: Removed deprecated asyncio JoinableQueue.

* bpo-23529: Limit the size of decompressed data when reading from
  GzipFile, BZ2File or LZMAFile.  This defeats denial of service
  attacks using compressed bombs (i.e. compressed payloads which
  decompress to a huge size).  Patch by Martin Panter and Nikolaus
  Rath.

* bpo-21859: Added Python implementation of io.FileIO.

* bpo-23865: close() methods in multiple modules now are idempotent
  and more robust at shutdown. If they need to release multiple
  resources, all are released even if errors occur.

* bpo-23400: Raise same exception on both Python 2 and 3 if sem_open
  is not available. Patch by Davin Potts.

* bpo-10838: The subprocess now module includes SubprocessError and
  TimeoutError in its list of exported names for the users wild enough
  to use "from subprocess import *".

* bpo-23411: Added DefragResult, ParseResult, SplitResult,
  DefragResultBytes, ParseResultBytes, and SplitResultBytes to
  urllib.parse.__all__. Patch by Martin Panter.

* bpo-23881: urllib.request.ftpwrapper constructor now closes the
  socket if the FTP connection failed to fix a ResourceWarning.

* bpo-23853: "socket.socket.sendall()" does no more reset the socket
  timeout each time data is sent successfully. The socket timeout is
  now the maximum total duration to send all data.

* bpo-22721: An order of multiline pprint output of set or dict
  containing orderable and non-orderable elements no longer depends on
  iteration order of set or dict.

* bpo-15133: _tkinter.tkapp.getboolean() now supports Tcl_Obj and
  always returns bool. tkinter.BooleanVar now validates input values
  (accepted bool, int, str, and Tcl_Obj).  tkinter.BooleanVar.get()
  now always returns bool.

* bpo-10590: xml.sax.parseString() now supports string argument.

* bpo-23338: Fixed formatting ctypes error messages on Cygwin. Patch
  by Makoto Kato.

* bpo-15582: inspect.getdoc() now follows inheritance chains.

* bpo-2175: SAX parsers now support a character stream of
  InputSource object.

* bpo-16840: Tkinter now supports 64-bit integers added in Tcl 8.4
  and arbitrary precision integers added in Tcl 8.5.

* bpo-23834: Fix socket.sendto(), use the C Py_ssize_t type to store
  the result of sendto() instead of the C int type.

* bpo-23618: "socket.socket.connect()" now waits until the
  connection completes instead of raising "InterruptedError" if the
  connection is interrupted by signals, signal handlers don't raise an
  exception and the socket is blocking or has a timeout.
  "socket.socket.connect()" still raise "InterruptedError" for non-
  blocking sockets.

* bpo-21526: Tkinter now supports new boolean type in Tcl 8.5.

* bpo-23836: Fix the faulthandler module to handle reentrant calls
  to its signal handlers.

* bpo-23838: linecache now clears the cache and returns an empty
  result on MemoryError.

* bpo-10395: Added os.path.commonpath(). Implemented in posixpath
  and ntpath. Based on patch by Rafik Draoui.

* bpo-23611: Serializing more "lookupable" objects (such as unbound
  methods or nested classes) now are supported with pickle protocols <
  4.

* bpo-13583: sqlite3.Row now supports slice indexing.

* bpo-18473: Fixed 2to3 and 3to2 compatible pickle mappings.  Fixed
  ambiguous reverse mappings.  Added many new mappings.  Import
  mapping is no longer applied to modules already mapped with full
  name mapping.

* bpo-23485: select.select() is now retried automatically with the
  recomputed timeout when interrupted by a signal, except if the
  signal handler raises an exception. This change is part of the **PEP
  475**.

* bpo-23752: When built from an existing file descriptor,
  io.FileIO() now only calls fstat() once. Before fstat() was called
  twice, which was not necessary.

* bpo-23704: collections.deque() objects now support __add__,
  __mul__, and __imul__().

* bpo-23171: csv.Writer.writerow() now supports arbitrary iterables.

* bpo-23745: The new email header parser now handles duplicate MIME
  parameter names without error, similar to how get_param behaves.

* bpo-22117: Fix os.utime(), it now rounds the timestamp towards
  minus infinity (-inf) instead of rounding towards zero.

* bpo-23310: Fix MagicMock's initializer to work with __methods__,
  just like configure_mock().  Patch by Kasia Jachim.


构建
----

* bpo-23817: FreeBSD now uses "1.0" in the SOVERSION as other
  operating systems, instead of just "1".

* bpo-23501: Argument Clinic now generates code into separate files
  by default.


测试
----

* bpo-23799: Added test.support.start_threads() for running and
  cleaning up multiple threads.

* bpo-22390: test.regrtest now emits a warning if temporary files or
  directories are left after running a test.


工具/示例
---------

* bpo-18128: pygettext now uses standard +NNNN format in the POT-
  Creation-Date header.

* bpo-23935: Argument Clinic's understanding of format units
  accepting bytes, bytearrays, and buffers is now consistent with both
  the documentation and the implementation.

* bpo-23944: Argument Clinic now wraps long impl prototypes at
  column 78.

* bpo-20586: Argument Clinic now ensures that functions without
  docstrings have signatures.

* bpo-23492: Argument Clinic now generates argument parsing code
  with PyArg_Parse instead of PyArg_ParseTuple if possible.

* bpo-23500: Argument Clinic is now smarter about generating the
  "#ifndef" (empty) definition of the methoddef macro: it's only
  generated once, even if Argument Clinic processes the same symbol
  multiple times, and it's emitted at the end of all processing rather
  than immediately after the first use.


C API
-----

* bpo-23998: PyImport_ReInitLock() now checks for lock allocation
  error


Python 3.5.0 alpha 3
====================

*Release date: 2015-03-28*


核心与内置
----------

* bpo-23573: Increased performance of string search operations
  (str.find, str.index, str.count, the in operator, str.split,
  str.partition) with arguments of different kinds (UCS1, UCS2, UCS4).

* bpo-23753: Python doesn't support anymore platforms without stat()
  or fstat(), these functions are always required.

* bpo-23681: The -b option now affects comparisons of bytes with
  int.

* bpo-23632: Memoryviews now allow tuple indexing (including for
  multi-dimensional memoryviews).

* bpo-23192: Fixed generator lambdas.  Patch by Bruno Cauet.

* bpo-23629: Fix the default __sizeof__ implementation for variable-
  sized objects.


库
--

* bpo-14260: The groupindex attribute of regular expression pattern
  object now is non-modifiable mapping.

* bpo-23792: Ignore KeyboardInterrupt when the pydoc pager is
  active. This mimics the behavior of the standard unix pagers, and
  prevents pipepager from shutting down while the pager itself is
  still running.

* bpo-23775: pprint() of OrderedDict now outputs the same
  representation as repr().

* bpo-23765: Removed IsBadStringPtr calls in ctypes

* bpo-22364: Improved some re error messages using regex for hints.

* bpo-23742: ntpath.expandvars() no longer loses unbalanced single
  quotes.

* bpo-21717: The zipfile.ZipFile.open function now supports 'x'
  (exclusive creation) mode.

* bpo-21802: The reader in BufferedRWPair now is closed even when
  closing writer failed in BufferedRWPair.close().

* bpo-23622: Unknown escapes in regular expressions that consist of
  "'\'" and ASCII letter now raise a deprecation warning and will be
  forbidden in Python 3.6.

* bpo-23671: string.Template now allows specifying the "self"
  parameter as a keyword argument.  string.Formatter now allows
  specifying the "self" and the "format_string" parameters as keyword
  arguments.

* bpo-23502: The pprint module now supports mapping proxies.

* bpo-17530: pprint now wraps long bytes objects and bytearrays.

* bpo-22687: Fixed some corner cases in breaking words in tetxtwrap.
  Got rid of quadratic complexity in breaking long words.

* bpo-4727: The copy module now uses pickle protocol 4 (PEP 3154)
  and supports copying of instances of classes whose __new__ method
  takes keyword-only arguments.

* bpo-23491: Added a zipapp module to support creating executable
  zip file archives of Python code. Registered ".pyz" and ".pyzw"
  extensions on Windows for these archives (PEP 441).

* bpo-23657: Avoid explicit checks for str in zipapp, adding support
  for pathlib.Path objects as arguments.

* bpo-23688: Added support of arbitrary bytes-like objects and
  avoided unnecessary copying of memoryview in gzip.GzipFile.write().
  Original patch by Wolfgang Maier.

* bpo-23252: Added support for writing ZIP files to unseekable
  streams.

* bpo-23647: Increase imaplib's MAXLINE to accommodate modern
  mailbox sizes.

* bpo-23539: If body is None, http.client.HTTPConnection.request now
  sets Content-Length to 0 for PUT, POST, and PATCH headers to avoid
  411 errors from some web servers.

* bpo-22351: The nntplib.NNTP constructor no longer leaves the
  connection and socket open until the garbage collector cleans them
  up.  Patch by Martin Panter.

* bpo-23704: collections.deque() objects now support methods for
  index(), insert(), and copy().  This allows deques to be registered
  as a MutableSequence and it improves their substitutability for
  lists.

* bpo-23715: "signal.sigwaitinfo()" and "signal.sigtimedwait()" are
  now retried when interrupted by a signal not in the *sigset*
  parameter, if the signal handler does not raise an exception.
  signal.sigtimedwait() recomputes the timeout with a monotonic clock
  when it is retried.

* bpo-23001: Few functions in modules mmap, ossaudiodev, socket,
  ssl, and codecs, that accepted only read-only bytes-like object now
  accept writable bytes-like object too.

* bpo-23646: If time.sleep() is interrupted by a signal, the sleep
  is now retried with the recomputed delay, except if the signal
  handler raises an exception (PEP 475).

* bpo-23136: _strptime now uniformly handles all days in week 0,
  including Dec 30 of previous year.  Based on patch by Jim Carroll.

* bpo-23700: Iterator of NamedTemporaryFile now keeps a reference to
  NamedTemporaryFile instance.  Patch by Bohuslav Kabrda.

* bpo-22903: The fake test case created by unittest.loader when it
  fails importing a test module is now picklable.

* bpo-22181: On Linux, os.urandom() now uses the new getrandom()
  syscall if available, syscall introduced in the Linux kernel 3.17.
  It is more reliable and more secure, because it avoids the need of a
  file descriptor and waits until the kernel has enough entropy.

* bpo-2211: Updated the implementation of the http.cookies.Morsel
  class. Setting attributes key, value and coded_value directly now is
  deprecated. update() and setdefault() now transform and check keys.
  Comparing for equality now takes into account attributes key, value
  and coded_value. copy() now returns a Morsel, not a dict.  repr()
  now contains all attributes. Optimized checking keys and quoting
  values.  Added new tests. Original patch by Demian Brecht.

* bpo-18983: Allow selection of output units in timeit. Patch by
  Julian Gindi.

* bpo-23631: Fix traceback.format_list when a traceback has been
  mutated.

* bpo-23568: Add rdivmod support to MagicMock() objects. Patch by
  Håkan Lövdahl.

* bpo-2052: Add charset parameter to HtmlDiff.make_file().

* bpo-23668: Support os.truncate and os.ftruncate on Windows.

* bpo-23138: Fixed parsing cookies with absent keys or values in
  cookiejar. Patch by Demian Brecht.

* bpo-23051: multiprocessing.Pool methods imap() and
  imap_unordered() now handle exceptions raised by an iterator.  Patch
  by Alon Diamant and Davin Potts.

* bpo-23581: Add matmul support to MagicMock. Patch by Håkan
  Lövdahl.

* bpo-23566: enable(), register(), dump_traceback() and
  dump_traceback_later() functions of faulthandler now accept file
  descriptors. Patch by Wei Wu.

* bpo-22928: Disabled HTTP header injections in http.client.
  Original patch by Demian Brecht.

* bpo-23615: Modules bz2, tarfile and tokenize now can be reloaded
  with imp.reload(). Patch by Thomas Kluyver.

* bpo-23605: os.walk() now calls os.scandir() instead of
  os.listdir(). The usage of os.scandir() reduces the number of calls
  to os.stat(). Initial patch written by Ben Hoyt.


构建
----

* bpo-23585: make patchcheck will ensure the interpreter is built.


测试
----

* bpo-23583: Added tests for standard IO streams in IDLE.

* bpo-22289: Prevent test_urllib2net failures due to ftp connection
  timeout.


工具/示例
---------

* bpo-22826: The result of open() in Tools/freeze/bkfile.py is now
  better compatible with regular files (in particular it now supports
  the context management protocol).


Python 3.5.0 alpha 2
====================

*Release date: 2015-03-09*


核心与内置
----------

* bpo-23571: PyObject_Call() and PyCFunction_Call() now raise a
  SystemError if a function returns a result and raises an exception.
  The SystemError is chained to the previous exception.


库
--

* bpo-22524: New os.scandir() function, part of the **PEP 471**:
  "os.scandir() function -- a better and faster directory iterator".
  Patch written by Ben Hoyt.

* bpo-23103: Reduced the memory consumption of IPv4Address and
  IPv6Address.

* bpo-21793: BaseHTTPRequestHandler again logs response code as
  numeric, not as stringified enum.  Patch by Demian Brecht.

* bpo-23476: In the ssl module, enable OpenSSL's
  X509_V_FLAG_TRUSTED_FIRST flag on certificate stores when it is
  available.

* bpo-23576: Avoid stalling in SSL reads when EOF has been reached
  in the SSL layer but the underlying connection hasn't been closed.

* bpo-23504: Added an __all__ to the types module.

* bpo-23563: Optimized utility functions in urllib.parse.

* bpo-7830: Flatten nested functools.partial.

* bpo-20204: Added the __module__ attribute to _tkinter classes.

* bpo-19980: Improved help() for non-recognized strings.  help('')
  now shows the help on str.  help('help') now shows the help on
  help(). Original patch by Mark Lawrence.

* bpo-23521: Corrected pure python implementation of timedelta
  division. Eliminated OverflowError from "timedelta * float" for some
  floats; Corrected rounding in timedelta true division.

* bpo-21619: Popen objects no longer leave a zombie after exit in
  the with statement if the pipe was broken.  Patch by Martin Panter.

* bpo-22936: Make it possible to show local variables in tracebacks
  for both the traceback module and unittest.

* bpo-15955: Add an option to limit the output size in
  bz2.decompress(). Patch by Nikolaus Rath.

* bpo-6639: Module-level turtle functions no longer raise TclError
  after closing the window.

* bpo-814253: Group references and conditional group references now
  work in lookbehind assertions in regular expressions. (See also:
  bpo-9179)

* bpo-23215: Multibyte codecs with custom error handlers that
  ignores errors consumed too much memory and raised SystemError or
  MemoryError. Original patch by Aleksi Torhamo.

* bpo-5700: io.FileIO() called flush() after closing the file.
  flush() was not called in close() if closefd=False.

* bpo-23374: Fixed pydoc failure with non-ASCII files when stdout
  encoding differs from file system encoding (e.g. on Mac OS).

* bpo-23481: Remove RC4 from the SSL module's default cipher list.

* bpo-21548: Fix pydoc.synopsis() and pydoc.apropos() on modules
  with empty docstrings.

* bpo-22885: Fixed arbitrary code execution vulnerability in the
  dbm.dumb module. Original patch by Claudiu Popa.

* bpo-23239: ssl.match_hostname() now supports matching of IP
  addresses.

* bpo-23146: Fix mishandling of absolute Windows paths with forward
  slashes in pathlib.

* bpo-23096: Pickle representation of floats with protocol 0 now is
  the same for both Python and C implementations.

* bpo-19105: pprint now more efficiently uses free space at the
  right.

* bpo-14910: Add allow_abbrev parameter to argparse.ArgumentParser.
  Patch by Jonathan Paugh, Steven Bethard, paul j3 and Daniel
  Eriksson.

* bpo-21717: tarfile.open() now supports 'x' (exclusive creation)
  mode.

* bpo-23344: marshal.dumps() is now 20-25% faster on average.

* bpo-20416: marshal.dumps() with protocols 3 and 4 is now 40-50%
  faster on average.

* bpo-23421: Fixed compression in tarfile CLI.  Patch by wdv4758h.

* bpo-23367: Fix possible overflows in the unicodedata module.

* bpo-23361: Fix possible overflow in Windows subprocess creation
  code.

* logging.handlers.QueueListener now takes a respect_handler_level
  keyword argument which, if set to True, will pass messages to
  handlers taking handler levels into account.

* bpo-19705: turtledemo now has a visual sorting algorithm demo.
  Original patch from Jason Yeo.

* bpo-23801: Fix issue where cgi.FieldStorage did not always ignore
  the entire preamble to a multipart body.


构建
----

* bpo-23445: pydebug builds now use "gcc -Og" where possible, to
  make the resulting executable faster.

* bpo-23686: Update OS X 10.5 installer build to use OpenSSL 1.0.2a.


C API
-----

* bpo-20204: Deprecation warning is now raised for builtin types
  without the __module__ attribute.


Windows
-------

* bpo-23465: Implement **PEP 486** - Make the Python Launcher aware
  of virtual environments. Patch by Paul Moore.

* bpo-23437: Make user scripts directory versioned on Windows. Patch
  by Paul Moore.


Python 3.5.0 alpha 1
====================

*Release date: 2015-02-08*


核心与内置
----------

* bpo-23285: PEP 475 - EINTR handling.

* bpo-22735: Fix many edge cases (including crashes) involving
  custom mro() implementations.

* bpo-22896: Avoid using PyObject_AsCharBuffer(),
  PyObject_AsReadBuffer() and PyObject_AsWriteBuffer().

* bpo-21295: Revert some changes (bpo-16795) to AST line numbers and
  column offsets that constituted a regression.

* bpo-22986: Allow changing an object's __class__ between a dynamic
  type and static type in some cases.

* bpo-15859: PyUnicode_EncodeFSDefault(), PyUnicode_EncodeMBCS() and
  PyUnicode_EncodeCodePage() now raise an exception if the object is
  not a Unicode object. For PyUnicode_EncodeFSDefault(), it was
  already the case on platforms other than Windows. Patch written by
  Campbell Barton.

* bpo-21408: The default __ne__() now returns NotImplemented if
  __eq__() returned NotImplemented.  Original patch by Martin Panter.

* bpo-23321: Fixed a crash in str.decode() when error handler
  returned replacement string longer than malformed input data.

* bpo-22286: The "backslashreplace" error handlers now works with
  decoding and translating.

* bpo-23253: Delay-load ShellExecute[AW] in os.startfile for reduced
  startup overhead on Windows.

* bpo-22038: pyatomic.h now uses stdatomic.h or GCC built-in
  functions for atomic memory access if available. Patch written by
  Vitor de Lima and Gustavo Temple.

* bpo-20284: %-interpolation (aka printf) formatting added for bytes
  and bytearray.

* bpo-23048: Fix jumping out of an infinite while loop in the pdb.

* bpo-20335: bytes constructor now raises TypeError when encoding or
  errors is specified with non-string argument.  Based on patch by
  Renaud Blanch.

* bpo-22834: If the current working directory ends up being set to a
  non-existent directory then import will no longer raise
  FileNotFoundError.

* bpo-22869: Move the interpreter startup & shutdown code to a new
  dedicated pylifecycle.c module

* bpo-22847: Improve method cache efficiency.

* bpo-22335: Fix crash when trying to enlarge a bytearray to
  0x7fffffff bytes on a 32-bit platform.

* bpo-22653: Fix an assertion failure in debug mode when doing a
  reentrant dict insertion in debug mode.

* bpo-22643: Fix integer overflow in Unicode case operations (upper,
  lower, title, swapcase, casefold).

* bpo-17636: Circular imports involving relative imports are now
  supported.

* bpo-22604: Fix assertion error in debug mode when dividing a
  complex number by (nan+0j).

* bpo-21052: Do not raise ImportWarning when sys.path_hooks or
  sys.meta_path are set to None.

* bpo-16518: Use 'bytes-like object required' in error messages that
  previously used the far more cryptic "'x' does not support the
  buffer protocol.

* bpo-22470: Fixed integer overflow issues in "backslashreplace",
  "xmlcharrefreplace", and "surrogatepass" error handlers.

* bpo-22540: speed up "PyObject_IsInstance" and
  "PyObject_IsSubclass" in the common case that the second argument
  has metaclass "type".

* bpo-18711: Add a new "PyErr_FormatV" function, similar to
  "PyErr_Format" but accepting a "va_list" argument.

* bpo-22520: Fix overflow checking when generating the repr of a
  unicode object.

* bpo-22519: Fix overflow checking in PyBytes_Repr.

* bpo-22518: Fix integer overflow issues in latin-1 encoding.

* bpo-16324: _charset parameter of MIMEText now also accepts
  email.charset.Charset instances. Initial patch by Claude Paroz.

* bpo-1764286: Fix inspect.getsource() to support decorated
  functions. Patch by Claudiu Popa.

* bpo-18554: os.__all__ includes posix functions.

* bpo-21391: Use os.path.abspath in the shutil module.

* bpo-11471: avoid generating a JUMP_FORWARD instruction at the end
  of an if-block if there is no else-clause.  Original patch by Eugene
  Toder.

* bpo-22215: Now ValueError is raised instead of TypeError when str
  or bytes argument contains not permitted null character or byte.

* bpo-22258: Fix the internal function set_inheritable() on Illumos.
  This platform exposes the function "ioctl(FIOCLEX)", but calling it
  fails with errno is ENOTTY: "Inappropriate ioctl for device".
  set_inheritable() now falls back to the slower "fcntl()" ("F_GETFD"
  and then "F_SETFD").

* bpo-21389: Displaying the __qualname__ of the underlying function
  in the repr of a bound method.

* bpo-22206: Using pthread, PyThread_create_key() now sets errno to
  ENOMEM and returns -1 (error) on integer overflow.

* bpo-20184: Argument Clinic based signature introspection added for
  30 of the builtin functions.

* bpo-22116: C functions and methods (of the
  'builtin_function_or_method' type) can now be weakref'ed.  Patch by
  Wei Wu.

* bpo-22077: Improve index error messages for bytearrays, bytes,
  lists, and tuples by adding 'or slices'. Added ', not <typename>'
  for bytearrays. Original patch by Claudiu Popa.

* bpo-20179: Apply Argument Clinic to bytes and bytearray. Patch by
  Tal Einat.

* bpo-22082: Clear interned strings in slotdefs.

* 升级 Unicode 数据库到 7.0.0 版本。

* bpo-21897: Fix a crash with the f_locals attribute with closure
  variables when frame.clear() has been called.

* bpo-21205: Add a new "__qualname__" attribute to generator, the
  qualified name, and use it in the representation of a generator
  ("repr(gen)"). The default name of the generator ("__name__"
  attribute) is now get from the function instead of the code. Use
  "gen.gi_code.co_name" to get the name of the code.

* bpo-21669: With the aid of heuristics in SyntaxError.__init__, the
  parser now attempts to generate more meaningful (or at least more
  search engine friendly) error messages when "exec" and "print" are
  used as statements.

* bpo-21642: In the conditional if-else expression, allow an integer
  written with no space between itself and the "else" keyword (e.g.
  "True if 42else False") to be valid syntax.

* bpo-21523: Fix over-pessimistic computation of the stack effect of
  some opcodes in the compiler.  This also fixes a quadratic
  compilation time issue noticeable when compiling code with a large
  number of "and" and "or" operators.

* bpo-21418: Fix a crash in the builtin function super() when called
  without argument and without current frame (ex: embedded Python).

* bpo-21425: Fix flushing of standard streams in the interactive
  interpreter.

* bpo-21435: In rare cases, when running finalizers on objects in
  cyclic trash a bad pointer dereference could occur due to a subtle
  flaw in internal iteration logic.

* bpo-21377: PyBytes_Concat() now tries to concatenate in-place when
  the first argument has a reference count of 1.  Patch by Nikolaus
  Rath.

* bpo-20355: -W command line options now have higher priority than
  the PYTHONWARNINGS environment variable.  Patch by Arfrever.

* bpo-21274: Define PATH_MAX for GNU/Hurd in Python/pythonrun.c.

* bpo-20904: Support setting FPU precision on m68k.

* bpo-21209: Fix sending tuples to custom generator objects with the
  yield from syntax.

* bpo-21193: pow(a, b, c) now raises ValueError rather than
  TypeError when b is negative. Patch by Josh Rosenberg.

* bpo-21176: PEP 465: Add the '@' operator for matrix
  multiplication.

* bpo-21134: Fix segfault when str is called on an uninitialized
  UnicodeEncodeError, UnicodeDecodeError, or UnicodeTranslateError
  object.

* bpo-19537: Fix PyUnicode_DATA() alignment under m68k.  Patch by
  Andreas Schwab.

* bpo-20929: Add a type cast to avoid shifting a negative number.

* bpo-20731: Properly position in source code files even if they are
  opened in text mode. Patch by Serhiy Storchaka.

* bpo-20637: Key-sharing now also works for instance dictionaries of
  subclasses.  Patch by Peter Ingebretson.

* bpo-8297: Attributes missing from modules now include the module
  name in the error text.  Original patch by ysj.ray.

* bpo-19995: %c, %o, %x, and %X now raise TypeError on non-integer
  input.

* bpo-19655: The ASDL parser - used by the build process to generate
  code for managing the Python AST in C - was rewritten. The new
  parser is self contained and does not require to carry long the
  spark.py parser-generator library; spark.py was removed from the
  source base.

* bpo-12546: Allow "\x00" to be used as a fill character when using
  str, int, float, and complex __format__ methods.

* bpo-20480: Add ipaddress.reverse_pointer. Patch by Leon Weber.

* bpo-13598: Modify string.Formatter to support auto-numbering of
  replacement fields. It now matches the behavior of str.format() in
  this regard. Patches by Phil Elson and Ramchandra Apte.

* bpo-8931: Make alternate formatting ('#') for type 'c' raise an
  exception. In versions prior to 3.5, '#' with 'c' had no effect. Now
  specifying it is an error. Patch by Torsten Landschoff.

* bpo-23165: Perform overflow checks before allocating memory in the
  _Py_char2wchar function.


库
--

* bpo-23399: pyvenv creates relative symlinks where possible.

* bpo-20289: cgi.FieldStorage() now supports the context management
  protocol.

* bpo-13128: Print response headers for CONNECT requests when
  debuglevel > 0. Patch by Demian Brecht.

* bpo-15381: Optimized io.BytesIO to make less allocations and
  copyings.

* bpo-22818: Splitting on a pattern that could match an empty string
  now raises a warning.  Patterns that can only match empty strings
  are now rejected.

* bpo-23099: Closing io.BytesIO with exported buffer is rejected now
  to prevent corrupting exported buffer.

* bpo-23326: Removed __ne__ implementations.  Since fixing default
  __ne__ implementation in bpo-21408 they are redundant.

* bpo-23363: Fix possible overflow in itertools.permutations.

* bpo-23364: Fix possible overflow in itertools.product.

* bpo-23366: Fixed possible integer overflow in
  itertools.combinations.

* bpo-23369: Fixed possible integer overflow in
  _json.encode_basestring_ascii.

* bpo-23353: Fix the exception handling of generators in
  PyEval_EvalFrameEx(). At entry, save or swap the exception state
  even if PyEval_EvalFrameEx() is called with throwflag=0. At exit,
  the exception state is now always restored or swapped, not only if
  why is WHY_YIELD or WHY_RETURN. Patch co-written with Antoine
  Pitrou.

* bpo-14099: Restored support of writing ZIP files to tellable but
  non-seekable streams.

* bpo-14099: Writing to ZipFile and reading multiple ZipExtFiles is
  threadsafe now.

* bpo-19361: JSON decoder now raises JSONDecodeError instead of
  ValueError.

* bpo-18518: timeit now rejects statements which can't be compiled
  outside a function or a loop (e.g. "return" or "break").

* bpo-23094: Fixed readline with frames in Python implementation of
  pickle.

* bpo-23268: Fixed bugs in the comparison of ipaddress classes.

* bpo-21408: Removed incorrect implementations of __ne__() which
  didn't returned NotImplemented if __eq__() returned NotImplemented.
  The default __ne__() now works correctly.

* bpo-19996: "email.feedparser.FeedParser" now handles (malformed)
  headers with no key rather than assuming the body has started.

* bpo-20188: Support Application-Layer Protocol Negotiation (ALPN)
  in the ssl module.

* bpo-23133: Pickling of ipaddress objects now produces more compact
  and portable representation.

* bpo-23248: Update ssl error codes from latest OpenSSL git master.

* bpo-23266: Much faster implementation of
  ipaddress.collapse_addresses() when there are many non-consecutive
  addresses.

* bpo-23098: 64-bit dev_t is now supported in the os module.

* bpo-21817: When an exception is raised in a task submitted to a
  ProcessPoolExecutor, the remote traceback is now displayed in the
  parent process.  Patch by Claudiu Popa.

* bpo-15955: Add an option to limit output size when decompressing
  LZMA data.  Patch by Nikolaus Rath and Martin Panter.

* bpo-23250: In the http.cookies module, capitalize "HttpOnly" and
  "Secure" as they are written in the standard.

* bpo-23063: In the distutils' check command, fix parsing of reST
  with code or code-block directives.

* bpo-23209: selectors.BaseSelector.get_key() now raises a
  RuntimeError if the selector is closed. And
  selectors.BaseSelector.close() now clears its internal reference to
  the selector mapping to break a reference cycle. Initial patch
  written by Martin Richard. (See also: bpo-23225)

* bpo-17911: Provide a way to seed the linecache for a PEP-302
  module without actually loading the code.

* bpo-17911: Provide a new object API for traceback, including the
  ability to not lookup lines at all until the traceback is actually
  rendered, without any trace of the original objects being kept
  alive.

* bpo-19777: Provide a home() classmethod on Path objects.
  Contributed by Victor Salgado and Mayank Tripathi.

* bpo-23206: Make "json.dumps(..., ensure_ascii=False)" as fast as
  the default case of "ensure_ascii=True".  Patch by Naoki Inada.

* bpo-23185: Add math.inf and math.nan constants.

* bpo-23186: Add ssl.SSLObject.shared_ciphers() and
  ssl.SSLSocket.shared_ciphers() to fetch the client's list ciphers
  sent at handshake.

* bpo-23143: Remove compatibility with OpenSSLs older than 0.9.8.

* bpo-23132: Improve performance and introspection support of
  comparison methods created by functool.total_ordering.

* bpo-19776: Add an expanduser() method on Path objects.

* bpo-23112: Fix SimpleHTTPServer to correctly carry the query
  string and fragment when it redirects to add a trailing slash.

* bpo-21793: Added http.HTTPStatus enums (i.e. HTTPStatus.OK,
  HTTPStatus.NOT_FOUND). Patch by Demian Brecht.

* bpo-23093: In the io, module allow more operations to work on
  detached streams.

* bpo-23111: In the ftplib, make ssl.PROTOCOL_SSLv23 the default
  protocol version.

* bpo-22585: On OpenBSD 5.6 and newer, os.urandom() now calls
  getentropy(), instead of reading /dev/urandom, to get pseudo-random
  bytes.

* bpo-19104: pprint now produces evaluable output for wrapped
  strings.

* bpo-23071: Added missing names to codecs.__all__.  Patch by Martin
  Panter.

* bpo-22783: Pickling now uses the NEWOBJ opcode instead of the
  NEWOBJ_EX opcode if possible.

* bpo-15513: Added a __sizeof__ implementation for pickle classes.

* bpo-19858: pickletools.optimize() now aware of the MEMOIZE opcode,
  can produce more compact result and no longer produces invalid
  output if input data contains MEMOIZE opcodes together with PUT or
  BINPUT opcodes.

* bpo-22095: Fixed HTTPConnection.set_tunnel with default port.  The
  port value in the host header was set to "None".  Patch by Demian
  Brecht.

* bpo-23016: A warning no longer produces an AttributeError when the
  program is run with pythonw.exe.

* bpo-21775: shutil.copytree(): fix crash when copying to VFAT. An
  exception handler assumed that OSError objects always have a
  'winerror' attribute. That is not the case, so the exception handler
  itself raised AttributeError when run on Linux (and, presumably, any
  other non-Windows OS). Patch by Greg Ward.

* bpo-1218234: Fix inspect.getsource() to load updated source of
  reloaded module. Initial patch by Berker Peksag.

* bpo-21740: Support wrapped callables in doctest. Patch by Claudiu
  Popa.

* bpo-23009: Make sure selectors.EpollSelector.select() works when
  no FD is registered.

* bpo-22959: In the constructor of http.client.HTTPSConnection,
  prefer the context's check_hostname attribute over the
  *check_hostname* parameter.

* bpo-22696: Add function "sys.is_finalizing()" to know about
  interpreter shutdown.

* bpo-16043: Add a default limit for the amount of data
  xmlrpclib.gzip_decode will return. This resolves CVE-2013-1753.

* bpo-14099: ZipFile.open() no longer reopen the underlying file.
  Objects returned by ZipFile.open() can now operate independently of
  the ZipFile even if the ZipFile was created by passing in a file-
  like object as the first argument to the constructor.

* bpo-22966: Fix __pycache__ pyc file name clobber when pyc_compile
  is asked to compile a source file containing multiple dots in the
  source file name.

* bpo-21971: Update turtledemo doc and add module to the index.

* bpo-21032: Fixed socket leak if HTTPConnection.getresponse()
  fails. Original patch by Martin Panter.

* bpo-22407: Deprecated the use of re.LOCALE flag with str patterns
  or re.ASCII. It was newer worked.

* bpo-22902: The "ip" command is now used on Linux to determine MAC
  address in uuid.getnode().  Pach by Bruno Cauet.

* bpo-22960: Add a context argument to xmlrpclib.ServerProxy
  constructor.

* bpo-22389: Add contextlib.redirect_stderr().

* bpo-21356: Make ssl.RAND_egd() optional to support LibreSSL. The
  availability of the function is checked during the compilation.
  Patch written by Bernard Spil.

* bpo-22915: SAX parser now supports files opened with file
  descriptor or bytes path.

* bpo-22609: Constructors and update methods of mapping classes in
  the collections module now accept the self keyword argument.

* bpo-22940: Add readline.append_history_file.

* bpo-19676: Added the "namereplace" error handler.

* bpo-22788: Add *context* parameter to
  logging.handlers.HTTPHandler.

* bpo-22921: Allow SSLContext to take the *hostname* parameter even
  if OpenSSL doesn't support SNI.

* bpo-22894: TestCase.subTest() would cause the test suite to be
  stopped when in failfast mode, even in the absence of failures.

* bpo-22796: HTTP cookie parsing is now stricter, in order to
  protect against potential injection attacks.

* bpo-22370: Windows detection in pathlib is now more robust.

* bpo-22841: Reject coroutines in asyncio add_signal_handler().
  Patch by Ludovic.Gasc.

* bpo-19494: Added urllib.request.HTTPBasicPriorAuthHandler. Patch
  by Matej Cepl.

* bpo-22578: Added attributes to the re.error class.

* bpo-22849: Fix possible double free in the io.TextIOWrapper
  constructor.

* bpo-12728: Different Unicode characters having the same uppercase
  but different lowercase are now matched in case-insensitive regular
  expressions.

* bpo-22821: Fixed fcntl() with integer argument on 64-bit big-
  endian platforms.

* bpo-21650: Add an "--sort-keys" option to json.tool CLI.

* bpo-22824: Updated reprlib output format for sets to use set
  literals. Patch contributed by Berker Peksag.

* bpo-22824: Updated reprlib output format for arrays to display
  empty arrays without an unnecessary empty list.  Suggested by Serhiy
  Storchaka.

* bpo-22406: Fixed the uu_codec codec incorrectly ported to 3.x.
  Based on patch by Martin Panter.

* bpo-17293: uuid.getnode() now determines MAC address on AIX using
  netstat. Based on patch by Aivars Kalvāns.

* bpo-22769: Fixed ttk.Treeview.tag_has() when called without
  arguments.

* bpo-22417: Verify certificates by default in httplib (PEP 476).

* bpo-22775: Fixed unpickling of http.cookies.SimpleCookie with
  protocol 2 and above. Patch by Tim Graham.

* bpo-22776: Brought excluded code into the scope of a try block in
  SysLogHandler.emit().

* bpo-22665: Add missing get_terminal_size and SameFileError to
  shutil.__all__.

* bpo-6623: Remove deprecated Netrc class in the ftplib module.
  Patch by Matt Chaput.

* bpo-17381: Fixed handling of case-insensitive ranges in regular
  expressions.

* bpo-22410: Module level functions in the re module now cache
  compiled locale-dependent regular expressions taking into account
  the locale.

* bpo-22759: Query methods on pathlib.Path() (exists(), is_dir(),
  etc.) now return False when the underlying stat call raises
  NotADirectoryError.

* bpo-8876: distutils now falls back to copying files when hard
  linking doesn't work. This allows use with special filesystems such
  as VirtualBox shared folders.

* bpo-22217: Implemented reprs of classes in the zipfile module.

* bpo-22457: Honour load_tests in the start_dir of discovery.

* bpo-18216: gettext now raises an error when a .mo file has an
  unsupported major version number.  Patch by Aaron Hill.

* bpo-13918: Provide a locale.delocalize() function which can remove
  locale-specific number formatting from a string representing a
  number, without then converting it to a specific type.  Patch by
  Cédric Krier.

* bpo-22676: Make the pickling of global objects which don't have a
  __module__ attribute less slow.

* bpo-18853: Fixed ResourceWarning in shlex.__nain__.

* bpo-9351: Defaults set with set_defaults on an argparse subparser
  are no longer ignored when also set on the parent parser.

* bpo-7559: unittest test loading ImportErrors are reported as
  import errors with their import exception rather than as attribute
  errors after the import has already failed.

* bpo-19746: Make it possible to examine the errors from unittest
  discovery without executing the test suite. The new "errors"
  attribute on TestLoader exposes these non-fatal errors encountered
  during discovery.

* bpo-21991: Make email.headerregistry's header 'params' attributes
  be read-only (MappingProxyType).  Previously the dictionary was
  modifiable but a new one was created on each access of the
  attribute.

* bpo-22638: SSLv3 is now disabled throughout the standard library.
  It can still be enabled by instantiating a SSLContext manually.

* bpo-22641: In asyncio, the default SSL context for client
  connections is now created using ssl.create_default_context(), for
  stronger security.

* bpo-17401: Include closefd in io.FileIO repr.

* bpo-21338: Add silent mode for compileall. quiet parameters of
  compile_{dir, file, path} functions now have a multilevel value.
  Also, -q option of the CLI now have a multilevel value. Patch by
  Thomas Kluyver.

* bpo-20152: Convert the array and cmath modules to Argument Clinic.

* bpo-18643: Add socket.socketpair() on Windows.

* bpo-22435: Fix a file descriptor leak when socketserver bind
  fails.

* bpo-13096: Fixed segfault in CTypes POINTER handling of large
  values.

* bpo-11694: Raise ConversionError in xdrlib as documented.  Patch
  by Filip Gruszczyński and Claudiu Popa.

* bpo-19380: Optimized parsing of regular expressions.

* bpo-1519638: Now unmatched groups are replaced with empty strings
  in re.sub() and re.subn().

* bpo-18615: sndhdr.what/whathdr now return a namedtuple.

* bpo-22462: Fix pyexpat's creation of a dummy frame to make it
  appear in exception tracebacks.

* bpo-21965: Add support for in-memory SSL to the ssl module.  Patch
  by Geert Jansen.

* bpo-21173: Fix len() on a WeakKeyDictionary when .clear() was
  called with an iterator alive.

* bpo-11866: Eliminated race condition in the computation of names
  for new threads.

* bpo-21905: Avoid RuntimeError in pickle.whichmodule() when
  sys.modules is mutated while iterating.  Patch by Olivier Grisel.

* bpo-11271: concurrent.futures.Executor.map() now takes a
  *chunksize* argument to allow batching of tasks in child processes
  and improve performance of ProcessPoolExecutor.  Patch by Dan
  O'Reilly.

* bpo-21883: os.path.join() and os.path.relpath() now raise a
  TypeError with more helpful error message for unsupported or
  mismatched types of arguments.

* bpo-22219: The zipfile module CLI now adds entries for directories
  (including empty directories) in ZIP file.

* bpo-22449: In the ssl.SSLContext.load_default_certs, consult the
  environmental variables SSL_CERT_DIR and SSL_CERT_FILE on Windows.

* bpo-22508: The email.__version__ variable has been removed; the
  email code is no longer shipped separately from the stdlib, and
  __version__ hasn't been updated in several releases.

* bpo-20076: Added non derived UTF-8 aliases to locale aliases
  table.

* bpo-20079: Added locales supported in glibc 2.18 to locale alias
  table.

* bpo-20218: Added convenience methods read_text/write_text and
  read_bytes/ write_bytes to pathlib.Path objects.

* bpo-22396: On 32-bit AIX platform, don't expose os.posix_fadvise()
  nor os.posix_fallocate() because their prototypes in system headers
  are wrong.

* bpo-22517: When an io.BufferedRWPair object is deallocated, clear
  its weakrefs.

* bpo-22437: Number of capturing groups in regular expression is no
  longer limited by 100.

* bpo-17442: InteractiveInterpreter now displays the full chained
  traceback in its showtraceback method, to match the built in
  interactive interpreter.

* bpo-23392: Added tests for marshal C API that works with FILE*.

* bpo-10510: distutils register and upload methods now use HTML
  standards compliant CRLF line endings.

* bpo-9850: Fixed macpath.join() for empty first component.  Patch
  by Oleg Oshmyan.

* bpo-5309: distutils' build and build_ext commands now accept a
  "-j" option to enable parallel building of extension modules.

* bpo-22448: Improve canceled timer handles cleanup to prevent
  unbound memory usage. Patch by Joshua Moore-Oliva.

* bpo-22427: TemporaryDirectory no longer attempts to clean up twice
  when used in the with statement in generator.

* bpo-22362: Forbidden ambiguous octal escapes out of range 0-0o377
  in regular expressions.

* bpo-20912: Now directories added to ZIP file have correct Unix and
  MS-DOS directory attributes.

* bpo-21866: ZipFile.close() no longer writes ZIP64 central
  directory records if allowZip64 is false.

* bpo-22278: Fix urljoin problem with relative urls, a regression
  observed after changes to issue22118 were submitted.

* bpo-22415: Fixed debugging output of the GROUPREF_EXISTS opcode in
  the re module. Removed trailing spaces in debugging output.

* bpo-22423: Unhandled exception in thread no longer causes
  unhandled AttributeError when sys.stderr is None.

* bpo-21332: Ensure that "bufsize=1" in subprocess.Popen() selects
  line buffering, rather than block buffering.  Patch by Akira Li.

* bpo-21091: Fix API bug: email.message.EmailMessage.is_attachment
  is now a method.

* bpo-21079: Fix email.message.EmailMessage.is_attachment to return
  the correct result when the header has parameters as well as a
  value.

* bpo-22247: Add NNTPError to nntplib.__all__.

* bpo-22366: urllib.request.urlopen will accept a context object
  (SSLContext) as an argument which will then be used for HTTPS
  connection. Patch by Alex Gaynor.

* bpo-4180: The warnings registries are now reset when the filters
  are modified.

* bpo-22419: Limit the length of incoming HTTP request in wsgiref
  server to 65536 bytes and send a 414 error code for higher lengths.
  Patch contributed by Devin Cook.

* Lax cookie parsing in http.cookies could be a security issue when
  combined with non-standard cookie handling in some Web browsers.
  Reported by Sergey Bobrov.

* bpo-20537: logging methods now accept an exception instance as
  well as a Boolean value or exception tuple. Thanks to Yury Selivanov
  for the patch.

* bpo-22384: An exception in Tkinter callback no longer crashes the
  program when it is run with pythonw.exe.

* bpo-22168: Prevent turtle AttributeError with non-default Canvas
  on OS X.

* bpo-21147: sqlite3 now raises an exception if the request contains
  a null character instead of truncating it.  Based on patch by Victor
  Stinner.

* bpo-13968: The glob module now supports recursive search in
  subdirectories using the "**" pattern.

* bpo-21951: Fixed a crash in Tkinter on AIX when called Tcl command
  with empty string or tuple argument.

* bpo-21951: Tkinter now most likely raises MemoryError instead of
  crash if the memory allocation fails.

* bpo-22338: Fix a crash in the json module on memory allocation
  failure.

* bpo-12410: imaplib.IMAP4 now supports the context management
  protocol. Original patch by Tarek Ziadé.

* bpo-21270: We now override tuple methods in mock.call objects so
  that they can be used as normal call attributes.

* bpo-16662: load_tests() is now unconditionally run when it is
  present in a package's __init__.py. TestLoader.loadTestsFromModule()
  still accepts use_load_tests, but it is deprecated and ignored.  A
  new keyword-only attribute "pattern" is added and documented.  Patch
  given by Robert Collins, tweaked by Barry Warsaw.

* bpo-22226: First letter no longer is stripped from the "status"
  key in the result of Treeview.heading().

* bpo-19524: Fixed resource leak in the HTTP connection when an
  invalid response is received.  Patch by Martin Panter.

* bpo-20421: Add a .version() method to SSL sockets exposing the
  actual protocol version in use.

* bpo-19546: configparser exceptions no longer expose implementation
  details. Chained KeyErrors are removed, which leads to cleaner
  tracebacks. Patch by Claudiu Popa.

* bpo-22051: turtledemo no longer reloads examples to re-run them.
  Initialization of variables and gui setup should be done in main(),
  which is called each time a demo is run, but not on import.

* bpo-21933: Turtledemo users can change the code font size with a
  menu selection or control(command) '-' or '+' or control-mousewheel.
  Original patch by Lita Cho.

* bpo-21597: The separator between the turtledemo text pane and the
  drawing canvas can now be grabbed and dragged with a mouse.  The
  code text pane can be widened to easily view or copy the full width
  of the text.  The canvas can be widened on small screens.  Original
  patches by Jan Kanis and Lita Cho.

* bpo-18132: Turtledemo buttons no longer disappear when the window
  is shrunk.  Original patches by Jan Kanis and Lita Cho.

* bpo-22043: time.monotonic() is now always available.
  "threading.Lock.acquire()", "threading.RLock.acquire()" and socket
  operations now use a monotonic clock, instead of the system clock,
  when a timeout is used.

* bpo-21527: Add a default number of workers to ThreadPoolExecutor
  equal to 5 times the number of CPUs.  Patch by Claudiu Popa.

* bpo-22216: smtplib now resets its state more completely after a
  quit.  The most obvious consequence of the previous behavior was a
  STARTTLS failure during a connect/starttls/quit/connect/starttls
  sequence.

* bpo-22098: ctypes' BigEndianStructure and LittleEndianStructure
  now define an empty __slots__ so that subclasses don't always get an
  instance dict. Patch by Claudiu Popa.

* bpo-22185: Fix an occasional RuntimeError in
  threading.Condition.wait() caused by mutation of the waiters queue
  without holding the lock.  Patch by Doug Zongker.

* bpo-22287: On UNIX, _PyTime_gettimeofday() now uses
  clock_gettime(CLOCK_REALTIME) if available. As a side effect, Python
  now depends on the librt library on Solaris and on Linux (only with
  glibc older than 2.17).

* bpo-22182: Use e.args to unpack exceptions correctly in
  distutils.file_util.move_file. Patch by Claudiu Popa.

* The webbrowser module now uses subprocess's start_new_session=True
  rather than a potentially risky preexec_fn=os.setsid call.

* bpo-22042: signal.set_wakeup_fd(fd) now raises an exception if the
  file descriptor is in blocking mode.

* bpo-16808: inspect.stack() now returns a named tuple instead of a
  tuple. Patch by Daniel Shahaf.

* bpo-22236: Fixed Tkinter images copying operations in
  NoDefaultRoot mode.

* bpo-2527: Add a *globals* argument to timeit functions, in order
  to override the globals namespace in which the timed code is
  executed. Patch by Ben Roberts.

* bpo-22118: Switch urllib.parse to use RFC 3986 semantics for the
  resolution of relative URLs, rather than RFCs 1808 and 2396. Patch
  by Demian Brecht.

* bpo-21549: Added the "members" parameter to TarFile.list().

* bpo-19628: Allow compileall recursion depth to be specified with a
  -r option.

* bpo-15696: Add a __sizeof__ implementation for mmap objects on
  Windows.

* bpo-22068: Avoided reference loops with Variables and Fonts in
  Tkinter.

* bpo-22165: SimpleHTTPRequestHandler now supports undecodable file
  names.

* bpo-15381: Optimized line reading in io.BytesIO.

* bpo-8797: Raise HTTPError on failed Basic Authentication
  immediately. Initial patch by Sam Bull.

* bpo-20729: Restored the use of lazy
  iterkeys()/itervalues()/iteritems() in the mailbox module.

* bpo-21448: Changed FeedParser feed() to avoid O(N**2) behavior
  when parsing long line. Original patch by Raymond Hettinger.

* bpo-22184: The functools LRU Cache decorator factory now gives an
  earlier and clearer error message when the user forgets the required
  parameters.

* bpo-17923: glob() patterns ending with a slash no longer match
  non- dirs on AIX.  Based on patch by Delhallt.

* bpo-21725: Added support for RFC 6531 (SMTPUTF8) in smtpd.

* bpo-22176: Update the ctypes module's libffi to v3.1.  This
  release adds support for the Linux AArch64 and POWERPC ELF ABIv2
  little endian architectures.

* bpo-5411: Added support for the "xztar" format in the shutil
  module.

* bpo-21121: Don't force 3rd party C extensions to be built with
  -Werror=declaration-after-statement.

* bpo-21975: Fixed crash when using uninitialized sqlite3.Row (in
  particular when unpickling pickled sqlite3.Row).  sqlite3.Row is now
  initialized in the __new__() method.

* bpo-20170: Convert posixmodule to use Argument Clinic.

* bpo-21539: Add an *exists_ok* argument to "Pathlib.mkdir()" to
  mimic "mkdir -p" and "os.makedirs()" functionality.  When true,
  ignore FileExistsErrors.  Patch by Berker Peksag.

* bpo-22127: Bypass IDNA for pure-ASCII host names in the socket
  module (in particular for numeric IPs).

* bpo-21047: set the default value for the *convert_charrefs*
  argument of HTMLParser to True.  Patch by Berker Peksag.

* 在 html.entities 包中增加 __all__ 变量。

* bpo-15114: the strict mode and argument of HTMLParser,
  HTMLParser.error, and the HTMLParserError exception have been
  removed.

* bpo-22085: Dropped support of Tk 8.3 in Tkinter.

* bpo-21580: Now Tkinter correctly handles bytes arguments passed to
  Tk. In particular this allows initializing images from binary data.

* bpo-22003: When initialized from a bytes object, io.BytesIO() now
  defers making a copy until it is mutated, improving performance and
  memory use on some use cases. Patch by David Wilson.

* bpo-22018: On Windows, signal.set_wakeup_fd() now also supports
  sockets. A side effect is that Python depends to the WinSock
  library.

* bpo-22054: Add os.get_blocking() and os.set_blocking() functions
  to get and set the blocking mode of a file descriptor (False if the
  O_NONBLOCK flag is set, True otherwise). These functions are not
  available on Windows.

* bpo-17172: Make turtledemo start as active on OS X even when run
  with subprocess. Patch by Lita Cho.

* bpo-21704: Fix build error for _multiprocessing when semaphores
  are not available. Patch by Arfrever Frehtes Taifersar Arahesis.

* bpo-20173: Convert sha1, sha256, sha512 and md5 to ArgumentClinic.
  Patch by Vajrasky Kok.

* Fix repr(_socket.socket) on Windows 64-bit: don't fail with
  OverflowError on closed socket. repr(socket.socket) already works
  fine.

* bpo-22033: Reprs of most Python implemented classes now contain
  actual class name instead of hardcoded one.

* bpo-21947: The dis module can now disassemble generator-iterator
  objects based on their gi_code attribute. Patch by Clement Rouault.

* bpo-16133: The asynchat.async_chat.handle_read() method now
  ignores BlockingIOError exceptions.

* bpo-22044: Fixed premature DECREF in call_tzinfo_method. Patch by
  Tom Flanagan.

* bpo-19884: readline: Disable the meta modifier key if stdout is
  not a terminal to not write the ANSI sequence ""\033[1034h"" into
  stdout. This sequence is used on some terminal (ex: TERM=xterm-
  256color") to enable support of 8 bit characters.

* bpo-4350: Removed a number of out-of-dated and non-working for a
  long time Tkinter methods.

* bpo-6167: Scrollbar.activate() now returns the name of active
  element if the argument is not specified.  Scrollbar.set() now
  always accepts only 2 arguments.

* bpo-15275: Clean up and speed up the ntpath module.

* bpo-21888: plistlib's load() and loads() now work if the fmt
  parameter is specified.

* bpo-22032: __qualname__ instead of __name__ is now always used to
  format fully qualified class names of Python implemented classes.

* bpo-22031: Reprs now always use hexadecimal format with the "0x"
  prefix when contain an id in form " at 0x...".

* bpo-22018: signal.set_wakeup_fd() now raises an OSError instead of
  a ValueError on "fstat()" failure.

* bpo-21044: tarfile.open() now handles fileobj with an integer
  'name' attribute.  Based on patch by Antoine Pietri.

* bpo-21966: Respect -q command-line option when code module is ran.

* bpo-19076: Don't pass the redundant 'file' argument to
  self.error().

* bpo-16382: Improve exception message of warnings.warn() for bad
  category. Initial patch by Phil Elson.

* bpo-21932: os.read() now uses a "Py_ssize_t()" type instead of
  "int" for the size to support reading more than 2 GB at once. On
  Windows, the size is truncated to INT_MAX. As any call to os.read(),
  the OS may read less bytes than the number of requested bytes.

* bpo-21942: Fixed source file viewing in pydoc's server mode on
  Windows.

* bpo-11259: asynchat.async_chat().set_terminator() now raises a
  ValueError if the number of received bytes is negative.

* bpo-12523: asynchat.async_chat.push() now raises a TypeError if it
  doesn't get a bytes string

* bpo-21707: Add missing kwonlyargcount argument to
  ModuleFinder.replace_paths_in_code().

* bpo-20639: calling Path.with_suffix('') allows removing the suffix
  again. Patch by July Tikhonov.

* bpo-21714: Disallow the construction of invalid paths using
  Path.with_name().  Original patch by Antony Lee.

* bpo-15014: Added 'auth' method to smtplib to make implementing
  auth mechanisms simpler, and used it internally in the login method.

* bpo-21151: Fixed a segfault in the winreg module when "None" is
  passed as a "REG_BINARY" value to SetValueEx.  Patch by John
  Ehresman.

* bpo-21090: io.FileIO.readall() does not ignore I/O errors anymore.
  Before, it ignored I/O errors if at least the first C call read()
  succeed.

* bpo-5800: headers parameter of wsgiref.headers.Headers is now
  optional. Initial patch by Pablo Torres Navarrete and SilentGhost.

* bpo-21781: ssl.RAND_add() now supports strings longer than 2 GB.

* bpo-21679: Prevent extraneous fstat() calls during open().  Patch
  by Bohuslav Kabrda.

* bpo-21863: cProfile now displays the module name of C extension
  functions, in addition to their own name.

* bpo-11453: asyncore: emit a ResourceWarning when an unclosed
  file_wrapper object is destroyed. The destructor now closes the file
  if needed. The close() method can now be called twice: the second
  call does nothing.

* bpo-21858: Better handling of Python exceptions in the sqlite3
  module.

* bpo-21476: Make sure the email.parser.BytesParser TextIOWrapper is
  discarded after parsing, so the input file isn't unexpectedly
  closed.

* bpo-20295: imghdr now recognizes OpenEXR format images.

* bpo-21729: Used the "with" statement in the dbm.dumb module to
  ensure files closing. Patch by Claudiu Popa.

* bpo-21491: socketserver: Fix a race condition in child processes
  reaping.

* bpo-21719: Added the "st_file_attributes" field to os.stat_result
  on Windows.

* bpo-21832: Require named tuple inputs to be exact strings.

* bpo-21722: The distutils "upload" command now exits with a non-
  zero return code when uploading fails.  Patch by Martin Dengler.

* bpo-21723: asyncio.Queue: support any type of number (ex: float)
  for the maximum size. Patch written by Vajrasky Kok.

* bpo-21711: support for "site-python" directories has now been
  removed from the site module (it was deprecated in 3.4).

* bpo-17552: new socket.sendfile() method allowing a file to be sent
  over a socket by using high-performance os.sendfile() on UNIX. Patch
  by Giampaolo Rodola'.

* bpo-18039: dbm.dump.open() now always creates a new database when
  the flag has the value 'n'.  Patch by Claudiu Popa.

* bpo-21326: Add a new is_closed() method to asyncio.BaseEventLoop.
  run_forever() and run_until_complete() methods of
  asyncio.BaseEventLoop now raise an exception if the event loop was
  closed.

* bpo-21766: Prevent a security hole in CGIHTTPServer by URL
  unquoting paths before checking for a CGI script at that path.

* bpo-21310: Fixed possible resource leak in failed open().

* bpo-21256: Printout of keyword args should be in deterministic
  order in a mock function call. This will help to write better
  doctests.

* bpo-21677: Fixed chaining nonnormalized exceptions in io close()
  methods.

* bpo-11709: Fix the pydoc.help function to not fail when sys.stdin
  is not a valid file.

* bpo-21515: tempfile.TemporaryFile now uses os.O_TMPFILE flag is
  available.

* bpo-13223: Fix pydoc.writedoc so that the HTML documentation for
  methods that use 'self' in the example code is generated correctly.

* bpo-21463: In urllib.request, fix pruning of the FTP cache.

* bpo-21618: The subprocess module could fail to close open fds that
  were inherited by the calling process and already higher than POSIX
  resource limits would otherwise allow.  On systems with a
  functioning /proc/self/fd or /dev/fd interface the max is now
  ignored and all fds are closed.

* bpo-20383: Introduce importlib.util.module_from_spec() as the
  preferred way to create a new module.

* bpo-21552: Fixed possible integer overflow of too long string
  lengths in the tkinter module on 64-bit platforms.

* bpo-14315: The zipfile module now ignores extra fields in the
  central directory that are too short to be parsed instead of letting
  a struct.unpack error bubble up as this "bad data" appears in many
  real world zip files in the wild and is ignored by other zip tools.

* bpo-13742: Added "key" and "reverse" parameters to heapq.merge().
  (First draft of patch contributed by Simon Sapin.)

* bpo-21402: tkinter.ttk now works when default root window is not
  set.

* bpo-3015: _tkinter.create() now creates tkapp object with
  wantobject=1 by default.

* bpo-10203: sqlite3.Row now truly supports sequence protocol.  In
  particular it supports reverse() and negative indices.  Original
  patch by Claudiu Popa.

* bpo-18807: If copying (no symlinks) specified for a venv, then the
  python interpreter aliases (python, python3) are now created by
  copying rather than symlinking.

* bpo-20197: Added support for the WebP image type in the imghdr
  module. Patch by Fabrice Aneche and Claudiu Popa.

* bpo-21513: Speedup some properties of IP addresses (IPv4Address,
  IPv6Address) such as .is_private or .is_multicast.

* bpo-21137: Improve the repr for threading.Lock() and its variants
  by showing the "locked" or "unlocked" status.  Patch by Berker
  Peksag.

* bpo-21538: The plistlib module now supports loading of binary
  plist files when reference or offset size is not a power of two.

* bpo-21455: Add a default backlog to socket.listen().

* bpo-21525: Most Tkinter methods which accepted tuples now accept
  lists too.

* bpo-22166: With the assistance of a new internal
  _codecs._forget_codec helping function, test_codecs now clears the
  encoding caches to avoid the appearance of a reference leak

* bpo-22236: Tkinter tests now don't reuse default root window.  New
  root window is created for every test class.

* bpo-10744: Fix **PEP 3118** format strings on ctypes objects with
  a nontrivial shape.

* bpo-20826: Optimize ipaddress.collapse_addresses().

* bpo-21487: Optimize ipaddress.summarize_address_range() and
  ipaddress.{IPv4Network,IPv6Network}.subnets().

* bpo-21486: Optimize parsing of netmasks in ipaddress.IPv4Network
  and ipaddress.IPv6Network.

* bpo-13916: Disallowed the surrogatepass error handler for non
  UTF-* encodings.

* bpo-20998: Fixed re.fullmatch() of repeated single character
  pattern with ignore case. Original patch by Matthew Barnett.

* bpo-21075: fileinput.FileInput now reads bytes from standard
  stream if binary mode is specified.  Patch by Sam Kimbrel.

* bpo-19775: Add a samefile() method to pathlib Path objects.
  Initial patch by Vajrasky Kok.

* bpo-21226: Set up modules properly in
  PyImport_ExecCodeModuleObject (and friends).

* bpo-21398: Fix a unicode error in the pydoc pager when the
  documentation contains characters not encodable to the stdout
  encoding.

* bpo-16531: ipaddress.IPv4Network and ipaddress.IPv6Network now
  accept an (address, netmask) tuple argument, so as to easily
  construct network objects from existing addresses.

* bpo-21156: importlib.abc.InspectLoader.source_to_code() is now a
  staticmethod.

* bpo-21424: Simplified and optimized heaqp.nlargest() and
  nmsmallest() to make fewer tuple comparisons.

* bpo-21396: Fix TextIOWrapper(..., write_through=True) to not force
  a flush() on the underlying binary stream.  Patch by akira.

* bpo-18314: Unlink now removes junctions on Windows. Patch by Kim
  Gräsman

* bpo-21088: Bugfix for curses.window.addch() regression in 3.4.0.
  In porting to Argument Clinic, the first two arguments were
  reversed.

* bpo-21407: _decimal: The module now supports function signatures.

* bpo-10650: Remove the non-standard 'watchexp' parameter from the
  Decimal.quantize() method in the Python version.  It had never been
  present in the C version.

* bpo-21469: Reduced the risk of false positives in robotparser by
  checking to make sure that robots.txt has been read or does not
  exist prior to returning True in can_fetch().

* bpo-19414: Have the OrderedDict mark deleted links as unusable.
  This gives an early failure if the link is deleted during iteration.

* bpo-21421: Add __slots__ to the MappingViews ABC. Patch by Josh
  Rosenberg.

* bpo-21101: Eliminate double hashing in the C speed-up code for
  collections.Counter().

* bpo-21321: itertools.islice() now releases the reference to the
  source iterator when the slice is exhausted.  Patch by Anton
  Afanasyev.

* bpo-21057: TextIOWrapper now allows the underlying binary stream's
  read() or read1() method to return an arbitrary bytes-like object
  (such as a memoryview). Patch by Nikolaus Rath.

* bpo-20951: SSLSocket.send() now raises either SSLWantReadError or
  SSLWantWriteError on a non-blocking socket if the operation would
  block. Previously, it would return 0.  Patch by Nikolaus Rath.

* bpo-13248: removed previously deprecated asyncore.dispatcher
  __getattr__ cheap inheritance hack.

* bpo-9815: assertRaises now tries to clear references to local
  variables in the exception's traceback.

* bpo-19940: ssl.cert_time_to_seconds() now interprets the given
  time string in the UTC timezone (as specified in RFC 5280), not the
  local timezone.

* bpo-13204: Calling sys.flags.__new__ would crash the interpreter,
  now it raises a TypeError.

* bpo-19385: Make operations on a closed dbm.dumb database always
  raise the same exception.

* bpo-21207: Detect when the os.urandom cached fd has been closed or
  replaced, and open it anew.

* bpo-21291: subprocess's Popen.wait() is now thread safe so that
  multiple threads may be calling wait() or poll() on a Popen instance
  at the same time without losing the Popen.returncode value.

* bpo-21127: Path objects can now be instantiated from str subclass
  instances (such as "numpy.str_").

* bpo-15002: urllib.response object to use _TemporaryFileWrapper
  (and _TemporaryFileCloser) facility. Provides a better way to handle
  file descriptor close. Patch contributed by Christian Theune.

* bpo-12220: mindom now raises a custom ValueError indicating it
  doesn't support spaces in URIs instead of letting a 'split'
  ValueError bubble up.

* bpo-21068: The ssl.PROTOCOL* constants are now enum members.

* bpo-21276: posixmodule: Don't define USE_XATTRS on KFreeBSD and
  the Hurd.

* bpo-21262: New method assert_not_called for Mock. It raises
  AssertionError if the mock has been called.

* bpo-21238: New keyword argument "unsafe" to Mock. It raises
  "AttributeError" incase of an attribute startswith assert or assret.

* bpo-20896: ssl.get_server_certificate() now uses PROTOCOL_SSLv23,
  not PROTOCOL_SSLv3, for maximum compatibility.

* bpo-21239: patch.stopall() didn't work deterministically when the
  same name was patched more than once.

* bpo-21203: Updated fileConfig and dictConfig to remove
  inconsistencies. Thanks to Jure Koren for the patch.

* bpo-21222: Passing name keyword argument to mock.create_autospec
  now works.

* bpo-21197: Add lib64 -> lib symlink in venvs on 64-bit non-OS X
  POSIX.

* bpo-17498: Some SMTP servers disconnect after certain errors,
  violating strict RFC conformance.  Instead of losing the error code
  when we issue the subsequent RSET, smtplib now returns the error
  code and defers raising the SMTPServerDisconnected error until the
  next command is issued.

* bpo-17826: setting an iterable side_effect on a mock function
  created by create_autospec now works. Patch by Kushal Das.

* bpo-7776: Fix "Host:" header and reconnection when using
  http.client.HTTPConnection.set_tunnel(). Patch by Nikolaus Rath.

* bpo-20968: unittest.mock.MagicMock now supports division. Patch by
  Johannes Baiter.

* bpo-21529: Fix arbitrary memory access in JSONDecoder.raw_decode
  with a negative second parameter. Bug reported by Guido Vranken.
  (See also: CVE-2014-4616)

* bpo-21169: getpass now handles non-ascii characters that the input
  stream encoding cannot encode by re-encoding using the replace error
  handler.

* bpo-21171: Fixed undocumented filter API of the rot13 codec. Patch
  by Berker Peksag.

* bpo-20539: Improved math.factorial error message for large
  positive inputs and changed exception type (OverflowError ->
  ValueError) for large negative inputs.

* bpo-21172: isinstance check relaxed from dict to
  collections.Mapping.

* bpo-21155: asyncio.EventLoop.create_unix_server() now raises a
  ValueError if path and sock are specified at the same time.

* bpo-21136: Avoid unnecessary normalization of Fractions resulting
  from power and other operations.  Patch by Raymond Hettinger.

* bpo-17621: Introduce importlib.util.LazyLoader.

* bpo-21076: signal module constants were turned into enums. Patch
  by Giampaolo Rodola'.

* bpo-20636: Improved the repr of Tkinter widgets.

* bpo-19505: The items, keys, and values views of OrderedDict now
  support reverse iteration using reversed().

* bpo-21149: Improved thread-safety in logging cleanup during
  interpreter shutdown. Thanks to Devin Jeanpierre for the patch.

* bpo-21058: Fix a leak of file descriptor in
  "tempfile.NamedTemporaryFile()", close the file descriptor if
  "io.open()" fails

* bpo-21200: Return None from pkgutil.get_loader() when __spec__ is
  missing.

* bpo-21013: Enhance ssl.create_default_context() when used for
  server side sockets to provide better security by default.

* bpo-20145: "assertRaisesRegex" and "assertWarnsRegex" now raise a
  TypeError if the second argument is not a string or compiled regex.

* bpo-20633: Replace relative import by absolute import.

* bpo-20980: Stop wrapping exception when using ThreadPool.

* bpo-21082: In os.makedirs, do not set the process-wide umask. Note
  this changes behavior of makedirs when exist_ok=True.

* bpo-20990: Fix issues found by pyflakes for multiprocessing.

* bpo-21015: SSL contexts will now automatically select an elliptic
  curve for ECDH key exchange on OpenSSL 1.0.2 and later, and
  otherwise default to "prime256v1".

* bpo-21000: Improve the command-line interface of json.tool.

* bpo-20995: Enhance default ciphers used by the ssl module to
  enable better security and prioritize perfect forward secrecy.

* bpo-20884: Don't assume that __file__ is defined on
  importlib.__init__.

* bpo-21499: Ignore __builtins__ in several test_importlib.test_api
  tests.

* bpo-20627: xmlrpc.client.ServerProxy is now a context manager.

* bpo-19165: The formatter module now raises DeprecationWarning
  instead of PendingDeprecationWarning.

* bpo-13936: Remove the ability of datetime.time instances to be
  considered false in boolean contexts.

* bpo-18931: selectors module now supports /dev/poll on Solaris.
  Patch by Giampaolo Rodola'.

* bpo-19977: When the "LC_TYPE" locale is the POSIX locale ("C"
  locale), "sys.stdin" and "sys.stdout" are now using the
  "surrogateescape" error handler, instead of the "strict" error
  handler.

* bpo-20574: Implement incremental decoder for cp65001 code (Windows
  code page 65001, Microsoft UTF-8).

* bpo-20879: Delay the initialization of encoding and decoding
  tables for base32, ascii85 and base85 codecs in the base64 module,
  and delay the initialization of the unquote_to_bytes() table of the
  urllib.parse module, to not waste memory if these modules are not
  used.

* bpo-19157: Include the broadcast address in the usuable hosts for
  IPv6 in ipaddress.

* bpo-11599: When an external command (e.g. compiler) fails,
  distutils now prints out the whole command line (instead of just the
  command name) if the environment variable DISTUTILS_DEBUG is set.

* bpo-4931: distutils should not produce unhelpful "error: None"
  messages anymore. distutils.util.grok_environment_error is kept but
  doc-deprecated.

* bpo-20875: Prevent possible gzip "'read' is not defined"
  NameError. Patch by Claudiu Popa.

* bpo-11558: "email.message.Message.attach" now returns a more
  useful error message if "attach" is called on a message for which
  "is_multipart" is False.

* bpo-20283: RE pattern methods now accept the string keyword
  parameters as documented. The pattern and source keyword parameters
  are left as deprecated aliases.

* bpo-20778: Fix modulefinder to work with bytecode-only modules.

* bpo-20791: copy.copy() now doesn't make a copy when the input is a
  bytes object. Initial patch by Peter Otten.

* bpo-19748: On AIX, time.mktime() now raises an OverflowError for
  year outsize range [1902; 2037].

* bpo-19573: inspect.signature: Use enum for parameter kind
  constants.

* bpo-20726: inspect.signature: Make Signature and Parameter
  picklable.

* bpo-17373: Add inspect.Signature.from_callable method.

* bpo-20378: Improve repr of inspect.Signature and
  inspect.Parameter.

* bpo-20816: Fix inspect.getcallargs() to raise correct TypeError
  for missing keyword-only arguments. Patch by Jeremiah Lowin.

* bpo-20817: Fix inspect.getcallargs() to fail correctly if more
  than 3 arguments are missing. Patch by Jeremiah Lowin.

* bpo-6676: Ensure a meaningful exception is raised when attempting
  to parse more than one XML document per pyexpat xmlparser instance.
  (Original patches by Hirokazu Yamamoto and Amaury Forgeot d'Arc,
  with suggested wording by David Gutteridge)

* bpo-21117: Fix inspect.signature to better support
  functools.partial. Due to the specifics of functools.partial
  implementation, positional-or-keyword arguments passed as keyword
  arguments become keyword-only.

* bpo-20334: inspect.Signature and inspect.Parameter are now
  hashable. Thanks to Antony Lee for bug reports and suggestions.

* bpo-15916: doctest.DocTestSuite returns an empty
  unittest.TestSuite instead of raising ValueError if it finds no
  tests

* bpo-21209: Fix asyncio.tasks.CoroWrapper to workaround a bug in
  yield-from implementation in CPythons prior to 3.4.1.

* asyncio: Add gi_{frame,running,code} properties to CoroWrapper
  (upstream bpo-163).

* bpo-21311: Avoid exception in _osx_support with non-standard
  compiler configurations. Patch by John Szakmeister.

* bpo-11571: Ensure that the turtle window becomes the topmost
  window when launched on OS X.

* bpo-21801: Validate that __signature__ is None or an instance of
  Signature.

* bpo-21923: Prevent AttributeError in
  distutils.sysconfig.customize_compiler due to possible uninitialized
  _config_vars.

* bpo-21323: Fix http.server to again handle scripts in CGI
  subdirectories, broken by the fix for security bpo-19435.  Patch by
  Zach Byrne.

* bpo-22733: Fix ffi_prep_args not zero-extending argument values
  correctly on 64-bit Windows.

* bpo-23302: Default to TCP_NODELAY=1 upon establishing an
  HTTPConnection. Removed use of hard-coded MSS as it's an
  optimization that's no longer needed with Nagle disabled.


IDLE
----

* bpo-20577: Configuration of the max line length for the
  FormatParagraph extension has been moved from the General tab of the
  Idle preferences dialog to the FormatParagraph tab of the Config
  Extensions dialog. Patch by Tal Einat.

* bpo-16893: Update Idle doc chapter to match current Idle and add
  new information.

* bpo-3068: Add Idle extension configuration dialog to Options menu.
  Changes are written to HOME/.idlerc/config-extensions.cfg. Original
  patch by Tal Einat.

* bpo-16233: A module browser (File : Class Browser, Alt+C) requires
  an editor window with a filename.  When Class Browser is requested
  otherwise, from a shell, output window, or 'Untitled' editor, Idle
  no longer displays an error box. It now pops up an Open Module box
  (Alt+M). If a valid name is entered and a module is opened, a
  corresponding browser is also opened.

* bpo-4832: Save As to type Python files automatically adds .py to
  the name you enter (even if your system does not display it).  Some
  systems automatically add .txt when type is Text files.

* bpo-21986: Code objects are not normally pickled by the pickle
  module. To match this, they are no longer pickled when running under
  Idle.

* bpo-17390: Adjust Editor window title; remove 'Python', move
  version to end.

* bpo-14105: Idle debugger breakpoints no longer disappear when
  inserting or deleting lines.

* bpo-17172: Turtledemo can now be run from Idle. Currently, the
  entry is on the Help menu, but it may move to Run. Patch by
  Ramchandra Apt and Lita Cho.

* bpo-21765: Add support for non-ascii identifiers to HyperParser.

* bpo-21940: Add unittest for WidgetRedirector. Initial patch by
  Saimadhav Heblikar.

* bpo-18592: Add unittest for SearchDialogBase. Patch by Phil
  Webster.

* bpo-21694: Add unittest for ParenMatch. Patch by Saimadhav
  Heblikar.

* bpo-21686: add unittest for HyperParser. Original patch by
  Saimadhav Heblikar.

* bpo-12387: Add missing upper(lower)case versions of default
  Windows key bindings for Idle so Caps Lock does not disable them.
  Patch by Roger Serwy.

* bpo-21695: Closing a Find-in-files output window while the search
  is still in progress no longer closes Idle.

* bpo-18910: Add unittest for textView. Patch by Phil Webster.

* bpo-18292: Add unittest for AutoExpand. Patch by Saihadhav
  Heblikar.

* bpo-18409: Add unittest for AutoComplete. Patch by Phil Webster.

* bpo-21477: htest.py - Improve framework, complete set of tests.
  Patches by Saimadhav Heblikar

* bpo-18104: Add idlelib/idle_test/htest.py with a few sample tests
  to begin consolidating and improving human-validated tests of Idle.
  Change other files as needed to work with htest.  Running the module
  as __main__ runs all tests.

* bpo-21139: Change default paragraph width to 72, the **PEP 8**
  recommendation.

* bpo-21284: Paragraph reformat test passes after user changes
  reformat width.

* bpo-17654: Ensure IDLE menus are customized properly on OS X for
  non-framework builds and for all variants of Tk.

* bpo-23180: Rename IDLE "Windows" menu item to "Window". Patch by
  Al Sweigart.


构建
----

* bpo-15506: Use standard PKG_PROG_PKG_CONFIG autoconf macro in the
  configure script.

* bpo-22935: Allow the ssl module to be compiled if openssl doesn't
  support SSL 3.

* bpo-22592: Drop support of the Borland C compiler to build Python.
  The distutils module still supports it to build extensions.

* bpo-22591: Drop support of MS-DOS, especially of the DJGPP
  compiler (MS-DOS port of GCC).

* bpo-16537: Check whether self.extensions is empty in setup.py.
  Patch by Jonathan Hosmer.

* bpo-22359: Remove incorrect uses of recursive make.  Patch by
  Jonas Wagner.

* bpo-21958: Define HAVE_ROUND when building with Visual Studio 2013
  and above.  Patch by Zachary Turner.

* bpo-18093: the programs that embed the CPython runtime are now in
  a separate "Programs" directory, rather than being kept in the
  Modules directory.

* bpo-15759: "make suspicious", "make linkcheck" and "make doctest"
  in Doc/ now display special message when and only when there are
  failures.

* bpo-21141: The Windows build process no longer attempts to find
  Perl, instead relying on OpenSSL source being configured and ready
  to build. The "PCbuild\build_ssl.py" script has been re-written and
  re-named to "PCbuild\prepare_ssl.py", and takes care of configuring
  OpenSSL source for both 32 and 64 bit platforms.  OpenSSL sources
  obtained from svn.python.org will always be pre-configured and ready
  to build.

* bpo-21037: Add a build option to enable AddressSanitizer support.

* bpo-19962: The Windows build process now creates "python.bat" in
  the root of the source tree, which passes all arguments through to
  the most recently built interpreter.

* bpo-21285: Refactor and fix curses configure check to always
  search in a ncursesw directory.

* bpo-15234: For BerkelyDB and Sqlite, only add the found library
  and include directories if they aren't already being searched. This
  avoids an explicit runtime library dependency.

* bpo-17861: Tools/scripts/generate_opcode_h.py automatically
  regenerates Include/opcode.h from Lib/opcode.py if the latter gets
  any change.

* bpo-20644: OS X installer build support for documentation build
  changes in 3.4.1: assume externally supplied sphinx-build is
  available in /usr/bin.

* bpo-20022: Eliminate use of deprecated bundlebuilder in OS X
  builds.

* bpo-15968: Incorporated Tcl, Tk, and Tix builds into the Windows
  build solution.

* bpo-17095: Fix Modules/Setup *shared* support.

* bpo-21811: Anticipated fixes to support OS X versions > 10.9.

* bpo-21166: Prevent possible segfaults and other random failures of
  python --generate-posix-vars in pybuilddir.txt build target.

* bpo-18096: Fix library order returned by python-config.

* bpo-17219: Add library build dir for Python extension cross-
  builds.

* bpo-22919: Windows build updated to support VC 14.0 (Visual Studio
  2015), which will be used for the official release.

* bpo-21236: Build _msi.pyd with cabinet.lib instead of fci.lib

* bpo-17128: Use private version of OpenSSL for OS X 10.5+
  installer.


C API
-----

* bpo-14203: Remove obsolete support for view==NULL in
  PyBuffer_FillInfo(), bytearray_getbuffer(), bytesiobuf_getbuffer()
  and array_buffer_getbuf(). All functions now raise BufferError in
  that case.

* bpo-22445: PyBuffer_IsContiguous() now implements precise
  contiguity tests, compatible with NumPy's
  NPY_RELAXED_STRIDES_CHECKING compilation flag.  Previously the
  function reported false negatives for corner cases.

* bpo-22079: PyType_Ready() now checks that statically allocated
  type has no dynamically allocated bases.

* bpo-22453: Removed non-documented macro PyObject_REPR().

* bpo-18395: Rename "_Py_char2wchar()" to "Py_DecodeLocale()",
  rename "_Py_wchar2char()" to "Py_EncodeLocale()", and document these
  functions.

* bpo-21233: Add new C functions: PyMem_RawCalloc(), PyMem_Calloc(),
  PyObject_Calloc(), _PyObject_GC_Calloc(). bytes(int) is now using
  "calloc()" instead of "malloc()" for large objects which is faster
  and use less memory.

* bpo-20942: PyImport_ImportFrozenModuleObject() no longer sets
  __file__ to match what importlib does; this affects
  _frozen_importlib as well as any module loaded using
  imp.init_frozen().


文档
----

* bpo-19548: Update the codecs module documentation to better cover
  the distinction between text encodings and other codecs, together
  with other clarifications. Patch by Martin Panter.

* bpo-22394: Doc/Makefile now supports "make venv PYTHON=../python"
  to create a venv for generating the documentation, e.g., "make html
  PYTHON=venv/bin/python3".

* bpo-21514: The documentation of the json module now refers to new
  JSON RFC 7159 instead of obsoleted RFC 4627.

* bpo-21777: The binary sequence methods on bytes and bytearray are
  now documented explicitly, rather than assuming users will be able
  to derive the expected behaviour from the behaviour of the
  corresponding str methods.

* bpo-6916: undocument deprecated asynchat.fifo class.

* bpo-17386: Expanded functionality of the "Doc/make.bat" script to
  make it much more comparable to "Doc/Makefile".

* bpo-21312: Update the thread_foobar.h template file to include
  newer threading APIs. Patch by Jack McCracken.

* bpo-21043: Remove the recommendation for specific CA organizations
  and to mention the ability to load the OS certificates.

* bpo-20765: Add missing documentation for PurePath.with_name() and
  PurePath.with_suffix().

* bpo-19407: New package installation and distribution guides based
  on the Python Packaging Authority tools. Existing guides have been
  retained as legacy links from the distutils docs, as they still
  contain some required reference material for tool developers that
  isn't recorded anywhere else.

* bpo-19697: Document cases where __main__.__spec__ is None.


测试
----

* bpo-18982: Add tests for CLI of the calendar module.

* bpo-19548: Added some additional checks to test_codecs to ensure
  that statements in the updated documentation remain accurate. Patch
  by Martin Panter.

* bpo-22838: All test_re tests now work with unittest test
  discovery.

* bpo-22173: Update lib2to3 tests to use unittest test discovery.

* bpo-16000: Convert test_curses to use unittest.

* bpo-21456: Skip two tests in test_urllib2net.py if _ssl module not
  present. Patch by Remi Pointel.

* bpo-20746: Fix test_pdb to run in refleak mode (-R).  Patch by
  Xavier de Gaye.

* bpo-22060: test_ctypes has been somewhat cleaned up and
  simplified; it now uses unittest test discovery to find its tests.

* bpo-22104: regrtest.py no longer holds a reference to the suite of
  tests loaded from test modules that don't define test_main().

* bpo-22111: Assorted cleanups in test_imaplib.  Patch by Milan
  Oberkirch.

* bpo-22002: Added "load_package_tests" function to test.support and
  used it to implement/augment test discovery in test_asyncio,
  test_email, test_importlib, test_json, and test_tools.

* bpo-21976: Fix test_ssl to accept LibreSSL version strings.
  Thanks to William Orr.

* bpo-21918: Converted test_tools from a module to a package
  containing separate test files for each tested script.

* bpo-9554: Use modern unittest features in test_argparse. Initial
  patch by Denver Coneybeare and Radu Voicilas.

* bpo-20155: Changed HTTP method names in failing tests in
  test_httpservers so that packet filtering software (specifically
  Windows Base Filtering Engine) does not interfere with the
  transaction semantics expected by the tests.

* bpo-19493: Refactored the ctypes test package to skip tests
  explicitly rather than silently.

* bpo-18492: All resources are now allowed when tests are not run by
  regrtest.py.

* bpo-21634: Fix pystone micro-benchmark: use floor division instead
  of true division to benchmark integers instead of floating point
  numbers. Set pystone version to 1.2. Patch written by Lennart
  Regebro.

* bpo-21605: Added tests for Tkinter images.

* bpo-21493: Added test for ntpath.expanduser().  Original patch by
  Claudiu Popa.

* bpo-19925: Added tests for the spwd module. Original patch by
  Vajrasky Kok.

* bpo-21522: Added Tkinter tests for Listbox.itemconfigure(),
  PanedWindow.paneconfigure(), and Menu.entryconfigure().

* bpo-17756: Fix test_code test when run from the installed
  location.

* bpo-17752: Fix distutils tests when run from the installed
  location.

* bpo-18604: Consolidated checks for GUI availability.  All
  platforms now at least check whether Tk can be instantiated when the
  GUI resource is requested.

* bpo-21275: 修复KFreeBSD上的套接字测试。

* bpo-21223: Pass test_site/test_startup_imports when some of the
  extensions are built as builtins.

* bpo-20635: Added tests for Tk geometry managers.

* 增加freeze包的测试用例。

* bpo-20743: 修复test_tcl中的引用泄漏。

* bpo-21097: Move test_namespace_pkgs into test_importlib.

* bpo-21503: Use test_both() consistently in test_importlib.

* bpo-20939: Avoid various network test failures due to new redirect
  of http://www.python.org/ to https://www.python.org: use
  http://www.example.com instead.

* bpo-20668: asyncio tests no longer rely on tests.txt file. (Patch
  by Vajrasky Kok)

* bpo-21093: Prevent failures of ctypes test_macholib on OS X if a
  copy of libz exists in $HOME/lib or /usr/local/lib.

* bpo-22770: Prevent some Tk segfaults on OS X when running gui
  tests.

* bpo-23211: Workaround test_logging failure on some OS X 10.6
  systems.

* bpo-23345: Prevent test_ssl failures with large OpenSSL patch
  level values (like 0.9.8zc).


工具/示例
---------

* bpo-22314: pydoc now works when the LINES environment variable is
  set.

* bpo-22615: Argument Clinic now supports the "type" argument for
  the int converter. This permits using the int converter with enums
  and typedefs.

* bpo-20076: The makelocalealias.py script no longer ignores UTF-8
  mapping.

* bpo-20079: The makelocalealias.py script now can parse the
  SUPPORTED file from glibc sources and supports command line options
  for source paths.

* bpo-22201: Command-line interface of the zipfile module now
  correctly extracts ZIP files with directory entries.  Patch by Ryan
  Wilson.

* bpo-22120: For functions using an unsigned integer return
  converter, Argument Clinic now generates a cast to that type for the
  comparison to -1 in the generated code.  (This suppresses a
  compilation warning.)

* bpo-18974: Tools/scripts/diff.py now uses argparse instead of
  optparse.

* bpo-21906: 让Tools/scripts/md5sum.py可以工作在Python 3。由Zachary
  Ware提供补丁。

* bpo-21629: Fix Argument Clinic's "--converters" feature.

* 为2to3添加 "yield from" 的支持。

* Add support for the **PEP 465** matrix multiplication operator to
  2to3.

* bpo-16047: Fix module exception list and __file__ handling in
  freeze. Patch by Meador Inge.

* bpo-11824: Consider ABI tags in freeze. Patch by Meador Inge.

* bpo-20535: PYTHONWARNING no longer affects the run_tests.py
  script. Patch by Arfrever Frehtes Taifersar Arahesis.


Windows
-------

* bpo-23260: 更新Windows安装器

* The bundled version of Tcl/Tk has been updated to 8.6.3.  The most
  visible result of this change is the addition of new native file
  dialogs when running on Windows Vista or newer.  See Tcl/Tk's TIP
  432 for more information.  Also, this version of Tcl/Tk includes
  support for Windows 10.

* bpo-17896: The Windows build scripts now expect external library
  sources to be in "PCbuild\..\externals" rather than "PCbuild\..\..".

* bpo-17717: The Windows build scripts now use a copy of NASM pulled
  from svn.python.org to build OpenSSL.

* bpo-21907: Improved the batch scripts provided for building
  Python.

* bpo-22644: The bundled version of OpenSSL has been updated to
  1.0.1j.

* bpo-10747: Use versioned labels in the Windows start menu. Patch
  by Olive Kilburn.

* bpo-22980: .pyd files with a version and platform tag (for
  example, ".cp35-win32.pyd") will now be loaded in preference to
  those without tags.

**（有关旧版本的信息，请参阅HISTORY文件。)**
