Changelog¶
Python next¶
Release date: XXXX-XX-XX
Security¶
gh-127655: Fixed the
asyncio.selector_events._SelectorSocketTransport
transport not pausing writes for the protocol when the buffer reaches the high water mark when usingasyncio.WriteTransport.writelines()
.
Library¶
gh-93312: Include
<sys/pidfd.h>
to getos.PIDFD_NONBLOCK
constant. Patch by Victor Stinner.gh-122431:
readline.append_history_file()
now raises aValueError
when given a negative value.
Python 3.12.8 final¶
Release date: 2024-12-03
macOS¶
gh-124448: Update bundled Tcl/Tk in macOS installer to 8.6.15.
Windows¶
Tools/Demos¶
gh-126807: Fix extraction warnings in pygettext.py caused by mistaking function definitions for function calls.
Tests¶
gh-126909: Fix test_os extended attribute tests to work on filesystems with 1 KiB xattr size limit.
gh-125041: Re-enable skipped tests for
zlib
on the s390x architecture: only skip checks of the compressed bytes, which can be different between zlib's software implementation and the hardware-accelerated implementation.
Security¶
gh-126623: Upgrade libexpat to 2.6.4
Library¶
gh-127303: Publicly expose
EXACT_TOKEN_TYPES
intoken.__all__
.gh-123967: Fix faulthandler for trampoline frames. If the top-most frame is a trampoline frame, skip it. Patch by Victor Stinner.
gh-127182: Fix
io.StringIO.__setstate__()
crash, whenNone
was passed as the first value.gh-127217: Fix
urllib.request.pathname2url()
for paths starting with multiple slashes on Posix.gh-127035: Fix
shutil.which
on Windows. Now it looks at direct match if and only if the command ends with a PATHEXT extension or X_OK is not in mode. Support extensionless files if "." is in PATHEXT. Support PATHEXT extensions that end with a dot.gh-127078: Fix issue where
urllib.request.url2pathname()
failed to discard an extra slash before a UNC drive in the URL path on Windows.gh-126766: Fix issue where
urllib.request.url2pathname()
failed to discard any 'localhost' authority present in the URL.gh-126997: Fix support of STRING and GLOBAL opcodes with non-ASCII arguments in
pickletools
.pickletools.dis()
now outputs non-ASCII bytes in STRING, BINSTRING and SHORT_BINSTRING arguments as escaped (\xXX
).gh-126618: Fix the representation of
itertools.count
objects when the count value issys.maxsize
.gh-85168: Fix issue where
urllib.request.url2pathname()
andpathname2url()
always used UTF-8 when quoting and unquoting file URIs. They now use the filesystem encoding and error handler.gh-67877: Fix memory leaks when
regular expression
matching terminates abruptly, either because of a signal or because memory allocation fails.gh-126789: Fixed the values of
sysconfig.get_config_vars()
,sysconfig.get_paths()
, and their siblings when thesite
initialization happens aftersysconfig
has built a cache forsysconfig.get_config_vars()
.gh-126188: Update bundled pip to 24.3.1
gh-126766: Fix issue where
urllib.request.url2pathname()
failed to discard two leading slashes introducing an empty authority section.gh-126727:
locale.nl_langinfo(locale.ERA)
now returns multiple era description segments separated by semicolons. Previously it only returned the first segment on platforms with Glibc.gh-126699: Allow
collections.abc.AsyncIterator
to be a base for Protocols.gh-104745: Limit starting a patcher (from
unittest.mock.patch()
orunittest.mock.patch.object()
) more than once without stopping itgh-126595: Fix a crash when instantiating
itertools.count
with an initial count ofsys.maxsize
on debug builds. Patch by Bénédikt Tran.gh-120423: Fix issue where
urllib.request.pathname2url()
mishandled Windows paths with embedded forward slashes.gh-126565: Improve performances of
zipfile.Path.open()
for non-reading modes.gh-126505: Fix bugs in compiling case-insensitive
regular expressions
with character classes containing non-BMP characters: upper-case non-BMP character did was ignored and the ASCII flag was ignored when matching a character range whose upper bound is beyond the BMP region.gh-117378: Fixed the
multiprocessing
"forkserver"
start method forkserver process to correctly inherit the parent'ssys.path
during the importing ofmultiprocessing.set_forkserver_preload()
modules in the same manner assys.path
is configured in workers before executing work items.This bug caused some forkserver module preloading to silently fail to preload. This manifested as a performance degration in child processes when the
sys.path
was required due to additional repeated work in every worker.It could also have a side effect of
""
remaining insys.path
during forkserver preload imports instead of the absolute path fromos.getcwd()
at multiprocessing import time used in the workersys.path
.The
sys.path
differences between phases in the child process could potentially have caused preload to import incorrect things from the wrong location. We are unaware of that actually having happened in practice.gh-125679: The
multiprocessing.Lock
andmultiprocessing.RLock
repr
values no longer say "unknown" on macOS.gh-126476: Raise
calendar.IllegalMonthError
(now a subclass ofIndexError
) forcalendar.month()
when the input month is not correct.gh-126489: The Python implementation of
pickle
no longer callspickle.Pickler.persistent_id()
for the result ofpersistent_id()
.gh-126303: Fix pickling and copying of
os.sched_param
objects.gh-126138: Fix a use-after-free crash on
asyncio.Task
objects whose underlying coroutine yields an object that implements an evil__getattribute__()
. Patch by Nico Posada.gh-126220: Fix crash in
cProfile.Profile
and_lsprof.Profiler
when their callbacks were directly called with 0 arguments.gh-126212: Fix issue where
urllib.request.pathname2url()
andurl2pathname()
removed slashes from Windows DOS drive paths and URLs.gh-126205: Fix issue where
urllib.request.pathname2url()
generated URLs beginning with four slashes (rather than two) when given a Windows UNC path.gh-126105: Fix a crash in
ast
when theast.AST._fields
attribute is deleted.gh-126106: Fixes a possible
NULL
pointer dereference inssl
.gh-126080: Fix a use-after-free crash on
asyncio.Task
objects for which the underlying event loop implements an evil__getattribute__()
. Reported by Nico-Posada. Patch by Bénédikt Tran.gh-126083: Fixed a reference leak in
asyncio.Task
objects when reinitializing the same object with a non-None
context. Patch by Nico Posada.gh-125984: Fix use-after-free crashes on
asyncio.Future
objects for which the underlying event loop implements an evil__getattribute__()
. Reported by Nico-Posada. Patch by Bénédikt Tran.gh-125969: Fix an out-of-bounds crash when an evil
asyncio.loop.call_soon()
mutates the length of the internal callbacks list. Patch by Bénédikt Tran.gh-125966: Fix a use-after-free crash in
asyncio.Future.remove_done_callback()
. Patch by Bénédikt Tran.gh-125789: Fix possible crash when mutating list of callbacks returned by
asyncio.Future._callbacks
. It now always returns a new copy in C implementation_asyncio
. Patch by Kumar Aditya.gh-124452: Fix an issue in
email.policy.EmailPolicy.header_source_parse()
andemail.policy.Compat32.header_source_parse()
that introduced spurious leading whitespaces into header values when the header includes a newline character after the header name delimiter (:
) and before the value.gh-125884: Fixed the bug for
pdb
where it can't set breakpoints on functions with certain annotations.gh-125355: Fix several bugs in
argparse.ArgumentParser.parse_intermixed_args()
.The parser no longer changes temporarily during parsing.
Default values are not processed twice.
Required mutually exclusive groups containing positional arguments are now supported.
The missing arguments report now includes the names of all required optional and positional arguments.
Unknown options can be intermixed with positional arguments in parse_known_intermixed_args().
gh-125682: Reject non-ASCII digits in the Python implementation of
json.loads()
conforming to the JSON specification.gh-125660: Reject invalid unicode escapes for Python implementation of
json.loads()
.gh-125259: Fix the notes removal logic for errors thrown in enum initialization.
gh-125519: Improve traceback if
importlib.reload()
is called with an object that is not a module. Patch by Alex Waygood.gh-125451: Fix deadlock when
concurrent.futures.ProcessPoolExecutor
shuts down concurrently with an error when feeding a job to a worker process.gh-125422: Fixed the bug where
pdb
andbdb
can step into the bottom caller frame.gh-100141: Fixed the bug where
pdb
will be stuck in an infinite loop when debugging an empty file.gh-53203: Fix
time.strptime()
for%c
,%x
and%X
formats in many locales that use non-ASCII digits, like Persian, Burmese, Odia and Shan.gh-125254: Fix a bug where ArgumentError includes the incorrect ambiguous option in
argparse
.gh-61011: Fix inheritance of nested mutually exclusive groups from parent parser in
argparse.ArgumentParser
. Previously, all nested mutually exclusive groups lost their connection to the group containing them and were displayed as belonging directly to the parser.gh-52551: Fix encoding issues in
time.strftime()
, thestrftime()
method of thedatetime
classesdatetime
,date
andtime
and formatting of these classes. Characters not encodable in the current locale are now acceptable in the format string. Surrogate pairs and sequence of surrogatescape-encoded bytes are no longer recombinated. Embedded null character no longer terminates the format string.gh-125118: Don't copy arbitrary values to _Bool in the
struct
module.gh-125069: Fix an issue where providing a
pathlib.PurePath
object as an initializer argument to a secondPurePath
object with a different flavour resulted in arguments to the former object's initializer being joined by the latter object's flavour.gh-124969: Fix
locale.nl_langinfo(locale.ALT_DIGITS)
on platforms with glibc. Now it returns a string consisting of up to 100 semicolon-separated symbols (an empty string in most locales) on all Posix platforms. Previously it only returned the first symbol or an empty string.gh-124958: Fix refcycles in exceptions raised from
asyncio.TaskGroup
and the python implementation ofasyncio.Future
gh-53203: Fix
time.strptime()
for%c
and%x
formats in many locales: Arabic, Bislama, Breton, Bodo, Kashubian, Chuvash, Estonian, French, Irish, Ge'ez, Gurajati, Manx Gaelic, Hebrew, Hindi, Chhattisgarhi, Haitian Kreyol, Japanese, Kannada, Korean, Marathi, Malay, Norwegian, Nynorsk, Punjabi, Rajasthani, Tok Pisin, Yoruba, Yue Chinese, Yau/Nungon and Chinese.gh-124917: Allow calling
os.path.exists()
andos.path.lexists()
with keyword arguments on Windows. Fixes a regression in 3.12.4.gh-124653: Fix detection of the minimal Queue API needed by the
logging
module. Patch by Bénédikt Tran.gh-124858: Fix reference cycles left in tracebacks in
asyncio.open_connection()
when used withhappy_eyeballs_delay
gh-124390: Fixed
AssertionError
when usingasyncio.staggered.staggered_race()
withasyncio.eager_task_factory
.gh-124651: Properly quote template strings in
venv
activation scripts.gh-124594: All
asyncio
REPL prompts run in the samecontext
. Contributed by Bartosz Sławecki.gh-120378: Fix a crash related to an integer overflow in
curses.resizeterm()
andcurses.resize_term()
.gh-123884: Fixed bug in itertools.tee() handling of other tee inputs (a tee in a tee). The output now has the promised n independent new iterators. Formerly, the first iterator was identical (not independent) to the input iterator. This would sometimes give surprising results.
gh-123978: Remove broken
time.thread_time()
andtime.thread_time_ns()
on NetBSD.gh-124008: Fix possible crash (in debug build), incorrect output or returning incorrect value from raw binary
write()
when writing to console on Windows.gh-123370: Fix the canvas not clearing after running turtledemo clock.
gh-120754: Update unbounded
read
calls inzipfile
to specify an explicitsize
putting a limit on how much data they may read. This also updates handling around ZIP max comment size to match the standard instead of reading comments that are one byte too long.gh-70764: Fixed an issue where
inspect.getclosurevars()
would incorrectly classify an attribute name as a global variable when the name exists both as an attribute name and a global variable.gh-119826: Always return an absolute path for
os.path.abspath()
on Windows.gh-101955: Fix SystemError when match regular expression pattern containing some combination of possessive quantifier, alternative and capture group.
gh-88110: Fixed
multiprocessing.Process
reporting a.exitcode
of 1 even on success when using the"fork"
start method while using aconcurrent.futures.ThreadPoolExecutor
.gh-71936: Fix a race condition in
multiprocessing.pool.Pool
.bpo-46128: Strip
unittest.IsolatedAsyncioTestCase
stack frames from reported stacktraces.bpo-14074: Fix
argparse
metavar processing to allow positional arguments to have a tuple metavar.
IDLE¶
gh-122392: Increase currently inadequate vertical spacing for the IDLE browsers (path, module, and stack) on high-resolution monitors.
Documentation¶
gh-125277: Require Sphinx 7.2.6 or later to build the Python documentation. Patch by Adam Turner.
gh-125018: The
importlib.metadata
documentation now includes semantic cross-reference targets for the significant documented APIs. This means intersphinx references likeimportlib.metadata.version()
will now work as expected.gh-121277: Writers of CPython's documentation can now use
next
as the version for theversionchanged
,versionadded
,deprecated
directives.gh-60712: Include the
object
type in the lists of documented types. Change by Furkan Onder and Martin Panter.
Core and Builtins¶
gh-113841: Fix possible undefined behavior division by zero in
complex
's_Py_c_pow()
.gh-126341: Now
ValueError
is raised instead ofSystemError
when trying to iterate over a releasedmemoryview
object.gh-126066: Fix
importlib
to not write an incomplete .pyc files when a ulimit or some other operating system mechanism is preventing the write to go through fully.gh-126139: Provide better error location when attempting to use a future statement with an unknown future feature.
gh-125008: Fix
tokenize.untokenize()
producing invalid syntax for double braces preceded by certain escape characters.gh-123378: Fix a crash in the
__str__()
method ofUnicodeError
objects when theUnicodeError.start
andUnicodeError.end
values are invalid or out-of-range. Patch by Bénédikt Tran.gh-116510: Fix a crash caused by immortal interned strings being shared between sub-interpreters that use basic single-phase init. In that case, the string can be used by an interpreter that outlives the interpreter that created and interned it. For interpreters that share obmalloc state, also share the interned dict with the main interpreter.
gh-118950: Fix bug where SSLProtocol.connection_lost wasn't getting called when OSError was thrown on writing to socket.
gh-113570: Fixed a bug in
reprlib.repr
where it incorrectly called the repr method on shadowed Python built-in types.gh-109746: If
_thread.start_new_thread()
fails to start a new thread, it deletes its state from interpreter and thus avoids its repeated cleanup on finalization.
C API¶
gh-113601: Removed debug build assertions related to interning strings, which were falsely triggered by stable ABI extensions.
Build¶
Python 3.12.7 final¶
Release date: 2024-10-01
Windows¶
Tests¶
gh-124378: Updated
test_ttk
to pass with Tcl/Tk 8.6.15.
Security¶
gh-122792: Changed IPv4-mapped
ipaddress.IPv6Address
to consistently use the mapped IPv4 address value for deciding properties. Properties which have their behavior fixed areis_multicast
,is_reserved
,is_link_local
,is_global
, andis_unspecified
.
Library¶
gh-116850: Fix
argparse
for namespaces with not directly writable dict (e.g. classes).gh-58573: Fix conflicts between abbreviated long options in the parent parser and subparsers in
argparse
.gh-61181: Fix support of Le paramètre choices with string value in
argparse
. Substrings of the specified string no longer considered valid values.gh-80259: Fix
argparse
support of positional arguments withnargs='?'
,default=argparse.SUPPRESS
and specifiedtype
.gh-124498: Fix
typing.TypeAliasType
not to be generic, whentype_params
is an empty tuple.gh-124345:
argparse
vim supports abbreviated single-dash long options separated by=
from its value.gh-104860: Fix disallowing abbreviation of single-dash long options in
argparse
withallow_abbrev=False
.gh-63143: Fix parsing mutually exclusive arguments in
argparse
. Arguments with the value identical to the default value (e.g. booleans, small integers, empty or 1-character strings) are no longer considered "not present".gh-72795: Positional arguments with Le paramètre nargs equal to
'*'
orargparse.REMAINDER
are no longer required. This allows to use positional argument withnargs='*'
and withoutdefault
in mutually exclusive group and improves error message about required arguments.gh-59317: Fix parsing positional argument with Le paramètre nargs equal to
'?'
or'*'
if it is preceded by an option and another positional argument.gh-53780:
argparse
now ignores the first"--"
(double dash) between an option and command.gh-124217: Add RFC 9637 reserved IPv6 block
3fff::/20
inipaddress
module.gh-124248: Fixed potential crash when using
struct
to process zero-width 'Pascal string' fields (0p
).gh-81691: Fix handling of multiple
"--"
(double dashes) inargparse
. Only the first one has now been removed, all subsequent ones are now taken literally.gh-87041: Fix a bug in
argparse
where lengthy subparser argument help is incorrectly indented.gh-124171: Add workaround for broken
fmod()
implementations on Windows, that loose zero sign (e.g.fmod(-10, 1)
returns0.0
). Patch by Sergey B Kirpichev.gh-123934: Fix
unittest.mock.MagicMock
reseting magic methods return values after.reset_mock(return_value=True)
was called.gh-123935: Fix parent slots detection for dataclasses that inherit from classes with
__dictoffset__
.gh-123892: Add
"_wmi"
tosys.stdlib_module_names
. Patch by Victor Stinner.gh-116810: Resolve a memory leak introduced in CPython 3.10's
ssl
when thessl.SSLSocket.session
property was accessed. Speeds up read and write access to said property by no longer unnecessarily cloning session objects via serialization.gh-121735: When working with zip archives, importlib.resources now properly honors module-adjacent references (e.g.
files(pkg.mod)
and not justfiles(pkg)
).gh-119004: Fix a crash in OrderedDict.__eq__ when operands are mutated during the check. Patch by Bénédikt Tran.
bpo-44864: Do not translate user-provided strings in
argparse.ArgumentParser
.
IDLE¶
gh-112938: Fix uninteruptable hang when Shell gets rapid continuous output.
Core and Builtins¶
gh-116510: Fix a bug that can cause a crash when sub-interpreters use "basic" single-phase extension modules. Shared objects could refer to PyGC_Head nodes that had been freed as part of interpreter cleanup.
gh-124188: Fix reading and decoding a line from the source file witn non-UTF-8 encoding for syntax errors raised in the compiler.
gh-77894: Fix possible crash in the garbage collector when it tries to break a reference loop containing a
memoryview
object. Now amemoryview
object can only be cleared if there are no buffers that refer it.gh-98442: Fix too wide source locations of the cleanup instructions of a with statement.
gh-113993: Strings interned with
sys.intern()
are again garbage-collected when no longer used, as per the documentation. Strings interned with the C functionPyUnicode_InternInPlace()
are still immortal. Internals of the string interning mechanism have been changed. This may affect performance and identities ofstr
objects.
C API¶
gh-113993:
PyUnicode_InternInPlace()
no longer prevents its argument from being garbage collected.Several functions that take
char *
are now documented as possibly preventing string objects from being garbage collected; refer to their documentation for details:PyUnicode_InternFromString()
,PyDict_SetItemString()
,PyObject_SetAttrString()
,PyObject_DelAttrString()
,PyUnicode_InternFromString()
, andPyModule_Add*
convenience functions.
Build¶
Python 3.12.6 final¶
Release date: 2024-09-06
macOS¶
gh-123418: Updated macOS installer build to use OpenSSL 3.0.15.
Windows¶
Tools/Demos¶
gh-123418: Update GitHub CI workflows to use OpenSSL 3.0.15 and multissltests to use 3.0.15, 3.1.7, and 3.2.3.
Tests¶
gh-101525: Skip
test_gdb
if the binary is relocated by BOLT. Patch by Donghee Na.
Security¶
Library¶
gh-123270: Applied a more surgical fix for malformed payloads in
zipfile.Path
causing infinite loops (gh-122905) without breaking contents using legitimate characters.gh-123213:
xml.etree.ElementTree.Element.extend()
andElement
assignment no longer hide the internal exception if an erronous generator is passed. Patch by Bar Harel.gh-85110: Preserve relative path in URL without netloc in
urllib.parse.urlunsplit()
andurllib.parse.urlunparse()
.gh-123067: Fix quadratic complexity in parsing
"
-quoted cookie values with backslashes byhttp.cookies
.gh-122903:
zipfile.Path.glob
now correctly matches directories instead of silently omitting them.gh-122905:
zipfile.Path
objects now sanitize names from the zipfile.gh-122695: Fixed double-free when using
gc.get_referents()
with a freedasyncio.Future
iterator.gh-116263:
logging.handlers.RotatingFileHandler
no longer rolls over empty log files.gh-118814: Fix the
typing.TypeVar
constructor when name is passed by keyword.gh-122478: Remove internal frames from tracebacks shown in
code.InteractiveInterpreter
with non-defaultsys.excepthook()
. Save correct tracebacks insys.last_traceback
and update__traceback__
attribute ofsys.last_value
andsys.last_exc
.gh-113785:
csv
now correctly parses numeric fields (when used withcsv.QUOTE_NONNUMERIC
) which start with an escape character.gh-112182:
asyncio.futures.Future.set_exception()
now transformsStopIteration
intoRuntimeError
instead of hanging or other misbehavior. Patch contributed by Jamie Phan.gh-108172:
webbrowser
honors OS preferred browser on Linux when its desktop entry name contains the text of a known browser name.gh-102988:
email.utils.getaddresses()
andemail.utils.parseaddr()
now return('', '')
2-tuples in more situations where invalid email addresses are encountered instead of potentially inaccurate values. Add optional strict parameter to these two functions: usestrict=False
to get the old behavior, accept malformed inputs.getattr(email.utils, 'supports_strict_parsing', False)
can be use to check if the strict paramater is available. Patch by Thomas Dwyer and Victor Stinner to improve the CVE-2023-27043 fix.gh-99437:
runpy.run_path()
now decodes path-like objects, making sure __file__ and sys.argv[0] of the module being run are always strings.
IDLE¶
gh-120083: Add explicit black IDLE Hovertip foreground color needed for recent macOS. Fixes Sonoma showing unreadable white on pale yellow. Patch by John Riggles.
Core and Builtins¶
gh-123321: Prevent Parser/myreadline race condition from segfaulting on multi-threaded use. Patch by Bar Harel and Amit Wienner.
gh-122982: Extend the deprecation period for bool inversion (
~
) by two years.gh-123229: Fix valgrind warning by initializing the f-string buffers to 0 in the tokenizer. Patch by Pablo Galindo
gh-123142: Fix too-wide source location in exception tracebacks coming from broken iterables in comprehensions.
gh-123048: Fix a bug where pattern matching code could emit a
JUMP_FORWARD
with no source location.gh-123083: Fix a potential use-after-free in
STORE_ATTR_WITH_HINT
.gh-122527: Fix a crash that occurred when a
PyStructSequence
was deallocated after its type's dictionary was cleared by the GC. The type'stp_basicsize
now accounts for non-sequence fields that aren't included in thePy_SIZE
of the sequence.gh-93691: Fix source locations of instructions generated for with statements.
Build¶
Python 3.12.5 final¶
Release date: 2024-08-06
Windows¶
gh-122573: The Windows build of CPython now requires 3.10 or newer.
Tests¶
gh-59022: Add tests for
pkgutil.extend_path()
. Patch by Andreas Stocker.gh-99242:
os.getloadavg()
may throwOSError
when running regression tests under certain conditions (e.g. chroot). This error is now caught and ignored, since reporting load average is optional.gh-121084: Fix test_typing random leaks. Clear typing ABC caches when running tests for refleaks (
-R
option): call_abc_caches_clear()
on typing abstract classes and their subclasses. Patch by Victor Stinner.gh-121160: Add a test for
readline.set_history_length()
. Note that this test may fail on readline libraries.gh-121200: Fix
test_expanduser_pwd2()
oftest_posixpath
. Callgetpwnam()
to getpw_dir
, since it can be different thangetpwall()
pw_dir
. Patch by Victor Stinner.gh-121188: When creating the JUnit XML file, regrtest now escapes characters which are invalid in XML, such as the chr(27) control character used in ANSI escape sequences. Patch by Victor Stinner.
Security¶
gh-121957: Fixed missing audit events around interactive use of Python, now also properly firing for
python -i
, as well as forpython -m asyncio
. The event in question iscpython.run_stdin
.gh-122133: Authenticate the socket connection for the
socket.socketpair()
fallback on platforms whereAF_UNIX
is not available like Windows.Patch by Gregory P. Smith <greg@krypto.org> and Seth Larson <seth@python.org>. Reported by Ellie <el@horse64.org>
Library¶
gh-122744: Bump the version of pip bundled in ensurepip to version 24.2.
gh-122334: Fix crash when importing
ssl
after the main interpreter restarts.gh-87320: In
code.InteractiveInterpreter
, handle exceptions caused by calling a non-defaultsys.excepthook()
. Before, the exception bubbled up to the caller, ending the REPL.gh-122400: Handle
ValueError
s raised byos.stat()
infilecmp.dircmp
andfilecmp.cmpfiles()
. Patch by Bénédikt Tran.gh-121650:
email
headers with embedded newlines are now quoted on output. Thegenerator
will now refuse to serialize (write) headers that are unsafely folded or delimited; seeverify_generated_headers
. (Contributed by Bas Bloemsaat and Petr Viktorin in gh-121650.)gh-122332: Fixed segfault with
asyncio.Task.get_coro()
when using an eager task factory.gh-122170: Handle
ValueError
s raised byos.stat()
inlinecache
. Patch by Bénédikt Tran.gh-121723: Make
logging.config.dictConfig()
accept any object implementing the Queue public API. See the queue configuration section for details. Patch by Bénédikt Tran.gh-82951: Serializing objects with complex
__qualname__
(such as unbound methods and nested classes) by name no longer involves serializing parent objects by value in pickle protocols < 4.gh-120930: Fixed a bug introduced by gh-92081 that added an incorrect extra blank to encoded words occurring in wrapped headers.
gh-121474: Fix missing sanity check for
parties
arg inthreading.Barrier
constructor. Patch by Clinton Christian (pygeek).gh-121025: Improve the
__repr__()
offunctools.partialmethod
. Patch by Bénédikt Tran.gh-121018: Fixed issues where
argparse.ArgumentParser.parse_args()
did not honorexit_on_error=False
. Based on patch by Ben Hsing.gh-119614: Fix truncation of strings with embedded null characters in some internal operations in
tkinter
.gh-120910: When reading installed files from an egg, use
relative_to(walk_up=True)
to honor files installed outside of the installation root.gh-101830: Accessing the
tkinter
object's string representation no longer converts the underlying Tcl object to a string on Windows.gh-120811: Fix possible memory leak in
contextvars.Context.run()
.gh-120769: Make empty line in
pdb
repeats the last command even when the command is fromcmdqueue
.gh-120732: Fix
name
passing tounittest.mock.Mock
object when usingunittest.mock.create_autospec()
.gh-120495: Fix incorrect exception handling in Tab Nanny. Patch by Wulian233.
gh-120343: Fix column offset reporting for tokens that come after multiline f-strings in the
tokenize
module.gh-119600: Fix
unittest.mock.patch()
to not read attributes of the target whennew_callable
is set. Patch by Robert Collins.gh-120289: Fixed the use-after-free issue in
cProfile
by disallowingdisable()
andclear()
in external timers.gh-114053: Fix edge-case bug where
typing.get_type_hints()
would produce incorrect results if type parameters in a class scope were overridden by assignments in a class scope andfrom __future__ import annotations
semantics were enabled. Patch by Alex Waygood.gh-114053: Fix erroneous
NameError
when callinginspect.get_annotations()
witheval_str=True`
on a class that made use of PEP 695 type parameters in a module that hadfrom __future__ import annotations
at the top of the file. Patch by Alex Waygood.gh-120268: Prohibit passing
None
to pure-Pythondatetime.date.fromtimestamp()
to achieve consistency with C-extension implementation.gh-120244: Fix memory leak in
re.sub()
when the replacement string contains backreferences.gh-120211: Fix
tkinter.ttk
with Tcl/Tk 9.0.gh-71587: Fix crash in C version of
datetime.datetime.strptime()
when called again on the restarted interpreter.gh-117983: Defer the
threading
import inimportlib.util
until lazy loading is used.gh-119698: Fix
symtable.Class.get_methods()
and document its behaviour. Patch by Bénédikt Tran.gh-120121: Add
concurrent.futures.InvalidStateError
to module's__all__
.gh-65454:
unittest.mock.Mock.attach_mock()
no longer triggers a call to aPropertyMock
being attached.gh-81936:
help()
andshowtopic()
methods now respect a configured output argument topydoc.Helper
and not use the pager in such cases. Patch by Enrico Tröger.gh-119577: The
DeprecationWarning
emitted when testing the truth value of anxml.etree.ElementTree.Element
now describes unconditionally returningTrue
in a future version rather than raising an exception in Python 3.14.gh-119506: Fix
io.TextIOWrapper.write()
method breaks internal buffer when the method is called again during flushing internal buffer.gh-119189: When using the
**
operator orpow()
withFraction
as the base and an exponent that is not rational, a float, or a complex, the fraction is no longer converted to a float.gh-105623: Fix performance degradation in
logging.handlers.RotatingFileHandler
. Patch by Craig Robson.bpo-39324: Add mime type mapping for .md <-> text/markdown
IDLE¶
gh-122482: Change About IDLE to direct users to discuss.python.org instead of the now unused idle-dev email and mailing list.
gh-78889: Stop Shell freezes by blocking user access to non-method sys.stdout.shell attributes, which are all private.
gh-120104: Fix padding in config and search dialog windows in IDLE.
Documentation¶
gh-121749: Fix documentation for
PyModule_AddObjectRef()
.gh-120012: Clarify the behaviours of
multiprocessing.Queue.empty()
andmultiprocessing.SimpleQueue.empty()
on closed queues. Patch by Bénédikt Tran.
Core and Builtins¶
gh-122208: Dictionary watchers now only deliver the PyDict_EVENT_ADDED event when the insertion is in a known good state to succeed.
gh-122300: Preserve AST nodes for f-string with single-element format specifiers. Patch by Pablo Galindo
gh-122029: Emit
c_call
events insys.setprofile()
when aPyMethodObject
pointing to aPyCFunction
is called.gh-122026: Fix a bug that caused the tokenizer to not correctly identify mismatched parentheses inside f-strings in some situations. Patch by Pablo Galindo
gh-121657: Improve the
SyntaxError
message if the user tries to useyield from
outside a function.gh-117482: Unexpected slot wrappers are no longer created for builtin static types in subinterpreters.
gh-121439: Allow tuples of length 20 in the freelist to be reused.
gh-121130: Fix f-strings with debug expressions in format specifiers. Patch by Pablo Galindo
gh-120722: Correctly set the bytecode position on return instructions within lambdas. Patch by Jelle Zijlstra.
gh-120384: Fix an array out of bounds crash in
list_ass_subscript
, which could be invoked via some specificly tailored input: including concurrent modification of a list object, where one thread assigns a slice and another clears it.gh-120380: Fix Python implementation of
pickle.Pickler
forbytes
andbytearray
objects when using protocol version 5. Patch by Bénédikt Tran.gh-93691: Fix source locations of instructions generated for the iterator of a for statement.
gh-120198: Fix a crash when multiple threads read and write to the same
__class__
of an object concurrently.gh-120298: Fix use-after free in
list_richcompare_impl
which can be invoked via some specificly tailored evil input.gh-119666: Fix a compiler crash in the case where two comprehensions in class scope both reference
__class__
.bpo-24766: Fix handling of
doc
argument to subclasses ofproperty
.
Build¶
Python 3.12.4 final¶
Release date: 2024-06-06
Security¶
gh-118486:
os.mkdir()
on Windows now accepts mode of0o700
to restrict the new directory to the current user. This fixes CVE 2024-4030 affectingtempfile.mkdtemp()
in scenarios where the base temporary directory is more permissive than the default.gh-116741: Update bundled libexpat to 2.6.2
gh-117233: Detect BLAKE2, SHA3, Shake, & truncated SHA512 support in the OpenSSL-ish libcrypto library at build time. This allows
hashlib
to be used with libraries that do not to support every algorithm that upstream OpenSSL does.
Core and Builtins¶
gh-119821: Fix execution of annotation scopes within classes when
globals
is set to a non-dict. Patch by Jelle Zijlstra.gh-119311: Fix bug where names are unexpectedly mangled in the bases of generic classes.
gh-119395: Fix bug where names appearing after a generic class are mangled as if they are in the generic class.
gh-119213: Non-builtin modules built with argument clinic were crashing if used in a subinterpreter before the main interpreter. The objects that were causing the problem by leaking between interpreters carelessly have been fixed.
gh-119011: Fixes
type.__type_params__
to return an empty tuple instead of a descriptor.gh-118997: Fix _Py_ClearImmortal() assertion: use _Py_IsImmortal() to tolerate reference count lower than _Py_IMMORTAL_REFCNT. Fix the assertion for the stable ABI, when a C extension is built with Python 3.11 or lower. Patch by Victor Stinner.
gh-118513: Fix incorrect
UnboundLocalError
when two comprehensions in the same function both reference the same name, and in one comprehension the name is bound while in the other it's an implicit global.gh-118164: Break a loop between the Python implementation of the
decimal
module and the Python code for integer to string conversion. Also optimize integer to string conversion for values in the range from 9_000 to 135_000 decimal digits.gh-118272: Fix bug where
generator.close
does not free the generator frame's locals.gh-116767: Fix crash in compiler on 'async with' that has many context managers.
gh-117894: Prevent
agen.aclose()
objects being re-used after.throw()
.gh-117881: prevent concurrent access to an async generator via athrow().throw() or asend().throw()
gh-115874: Fixed a possible segfault during garbage collection of
_asyncio.FutureIter
objects
Library¶
gh-119819: Fix regression to allow logging configuration with multiprocessing queue types.
gh-89727: Fix issue with
shutil.rmtree()
where aRecursionError
is raised on deep directory trees.gh-89727: Partially fix issue with
shutil.rmtree()
where aRecursionError
is raised on deep directory trees. A recursion error is no longer raised whenrmtree.avoids_symlink_attacks
is false.gh-119118: Fix performance regression in the
tokenize
module by caching theline
token attribute and calculating the column offset more efficiently.gh-89727: Fix issue with
os.fwalk()
where aRecursionError
was raised on deep directory trees by adjusting the implementation to be iterative instead of recursive.gh-118263: Speed up
os.path.normpath()
with a direct C call.gh-113892: Now, the method
sock_connect
ofasyncio.ProactorEventLoop
raises aValueError
if given socket is not in non-blocking mode, as well as in other loop implementations.gh-118507: Fix
os.path.isfile()
on Windows for pipes.gh-119174: Fix high DPI causes turtledemo(turtle-graphics examples) windows blurry Patch by Wulian233 and Terry Jan Reedy
gh-118643: Fix an AttributeError in the
email
module when re-fold a long address list. Also fix more cases of incorrect encoding of the address separator in the address list.gh-58933: Make
pdb
return to caller frame correctly whenf_trace
of the caller frame is not setgh-118868: Fixed issue where kwargs were no longer passed to the logging handler QueueHandler
gh-118164: The Python implementation of the
decimal
module could appear to hang in relatively small power cases (like2**117
) if context precision was set to a very high value. A different method to check for exactly representable results is used now that doesn't rely on computing10**precision
(which could be effectively too large to compute).gh-118404: Fix
inspect.signature()
for non-comparable callables.gh-118314: Fix an edge case in
binascii.a2b_base64()
strict mode, where excessive padding is not detected when no padding is necessary.gh-118042: Fix an unraisable exception in
telnetlib.Telnet.__del__()
when the__init__()
method was not called.gh-118221: Fix a bug where
sqlite3.iterdump()
could fail if a customrow factory
was used. Patch by Erlend Aasland.gh-118013: Fix regression introduced in gh-103193 that meant that calling
inspect.getattr_static()
on an instance would cause a strong reference to that instance's class to persist in an internal cache in theinspect
module. This caused unexpected memory consumption if the class was dynamically created, the class held strong references to other objects which took up a significant amount of memory, and the cache contained the sole strong reference to the class. The fix for the regression leads to a slowdown ingetattr_static()
, but the function should still be significantly faster than it was in Python 3.11. Patch by Alex Waygood.gh-90848: Fixed
unittest.mock.create_autospec()
to configure parent mock with keyword arguments.gh-118168: Fix incorrect argument substitution when
typing.Unpack
is used with the builtintuple
.typing.Unpack
now raisesTypeError
when used with certain invalid types. Patch by Jelle Zijlstra.gh-118033: Fix
dataclasses.dataclass()
not creating a__weakref__
slot when subclassingtyping.Generic
.gh-117535: Do not try to get the source line for made up file name "sys" in
warnings
.gh-114053: Fix erroneous
NameError
when callingtyping.get_type_hints()
on a class that made use of PEP 695 type parameters in a module that hadfrom __future__ import annotations
at the top of the file. Patch by Alex Waygood.gh-117995: Don't raise
DeprecationWarning
when a sequence of parameters is used to bind indexed, nameless placeholders. See also gh-100668.gh-80361: Fix TypeError in
email.message.Message.get_payload()
when the charset is RFC 2231 encoded.gh-86650: Fix IndexError when parse some emails with invalid Message-ID (including one-off addresses generated by Microsoft Outlook).
gh-117691: Improve the error messages emitted by
tarfile
deprecation warnings relating to PEP 706. If afilter
argument is not provided toextract()
orextractall
, the deprecation warning now points to the line in the user's code where the relevant function was called. Patch by Alex Waygood.gh-77102:
site
module now parses.pth
file with UTF-8 first, and locale encoding ifUnicodeDecodeError
happened. It supported only locale encoding before.gh-117692: Fixes a bug when
doctest.DocTestFinder
was failing on wrappedbuiltin_function_or_method
.gh-117566:
ipaddress.IPv6Address.is_loopback()
will now returnTrue
for IPv4-mapped loopback addresses, i.e. addresses in the::ffff:127.0.0.0/104
address space.gh-117503: Fix support of non-ASCII user names in bytes paths in
os.path.expanduser()
on Posix.gh-117313: Only treat
'\n'
,'\r'
and'\r\n'
as line separators in re-folding theemail
messages. Preserve control characters'\v'
,'\f'
,'\x1c'
,'\x1d'
and'\x1e'
and Unicode line separators'\x85'
,'\u2028'
and'\u2029'
as is.gh-113171: Fixed various false positives and false negatives in
ipaddress.IPv4Address.is_private
(see these docs for details)
Also in the corresponding
ipaddress.IPv4Network
andipaddress.IPv6Network
attributes.gh-103956: Fix lack of newline characters in
trace
module output when line tracing is enabled but source code line for current frame is not available.gh-92081: Fix missing spaces in email headers when the spaces are mixed with encoded 8-bit characters.
gh-103194: Prepare Tkinter for C API changes in Tcl 8.7/9.0 to avoid
_tkinter.Tcl_Obj
being unexpectedly returned instead ofbool
,str
,bytearray
, orint
.gh-87106: Fixed handling in
inspect.Signature.bind()
of keyword arguments having the same name as positional-only arguments when a variadic keyword argument (e.g.**kwargs
) is present.bpo-45767: Fix integer conversion in
os.major()
,os.minor()
, andos.makedev()
. Support device numbers larger than2**63-1
. Support non-existent device number (NODEV
).bpo-40943: Fix several IndexError when parse emails with truncated Message-ID, address, routes, etc, e.g.
example@
.bpo-30988: Fix parsing of emails with invalid address headers having a leading or trailing dot. Patch by tsufeki.
gh-67693: Fix
urllib.parse.urlunparse()
andurllib.parse.urlunsplit()
for URIs with path starting with multiple slashes and no authority. Based on patch by Ashwin Ramaswami.bpo-15010:
unittest.TestLoader.discover()
now saves the original value ofunittest.TestLoader._top_level_dir
and restores it at the end of the call.
Documentation¶
Tests¶
gh-119050: regrtest test runner: Add XML support to the refleak checker (-R option). Patch by Victor Stinner.
Windows¶
gh-119690: Adds Unicode support and fixes audit events for
_winapi.CreateNamedPipe
.gh-119070: Fixes
py.exe
handling of shebangs like/usr/bin/env python3.12
, which were previously interpreted aspython3.exe
instead ofpython3.12.exe
.gh-118347: Fixes launcher updates not being installed.
gh-115009: Update Windows installer to use SQLite 3.45.3.
gh-90329: Suppress the warning displayed on virtual environment creation when the requested and created paths differ only by a short (8.3 style) name. Warnings will continue to be shown if a junction or symlink in the path caused the venv to be created in a different location than originally requested.
macOS¶
IDLE¶
bpo-34774: Use user-selected color theme for Help => IDLE Doc.
C API¶
gh-119585: Fix crash when a thread state that was created by
PyGILState_Ensure()
calls a destructor that duringPyThreadState_Clear()
that calls back intoPyGILState_Ensure()
andPyGILState_Release()
. This might occur when in the free-threaded build or when using thread-local variables whose destructors callPyGILState_Ensure()
.gh-117534: Improve validation logic in the C implementation of
datetime.fromisoformat()
to better handle invalid years. Patch by Vlad Efanov.
Python 3.12.3 final¶
Release date: 2024-04-09
Security¶
gh-115398: Allow controlling Expat >=2.6.0 reparse deferral (CVE 2023-52425) by adding five new methods:
gh-115399: Update bundled libexpat to 2.6.0
gh-115243: Fix possible crashes in
collections.deque.index()
when the deque is concurrently modified.gh-114572:
ssl.SSLContext.cert_store_stats()
andssl.SSLContext.get_ca_certs()
now correctly lock access to the certificate store, when thessl.SSLContext
is shared across multiple threads.
Core and Builtins¶
gh-109120: Added handle of incorrect star expressions, e.g
f(3, *)
. Patch by Grigoryev Semyongh-99108: Updated the
hashlib
built-in HACL* project C code from upstream that we use for many implementations when they are not present via OpenSSL in a given build. This also avoids the rare potential for a C symbol name one definition rule linking issue.gh-116735: For
INSTRUMENTED_CALL_FUNCTION_EX
, setarg0
tosys.monitoring.MISSING
instead ofNone
forCALL
event.gh-113964: Starting new threads and process creation through
os.fork()
are now only prevented once all non-daemon threads exit.gh-116604: Respect the status of the garbage collector when indirect calls are made via
PyErr_CheckSignals()
and the evaluation breaker. Patch by Pablo Galindogh-116626: Ensure
INSTRUMENTED_CALL_FUNCTION_EX
always emitsCALL
gh-116296: Fix possible refleak in
object.__reduce__()
internal error handling.gh-116034: Fix location of the error on a failed assertion.
gh-115823: Properly calculate error ranges in the parser when raising
SyntaxError
exceptions caused by invalid byte sequences. Patch by Pablo Galindogh-112087: For an empty reverse iterator for list will be reduced to
reversed()
. Patch by Donghee Na.gh-115154: Fix a bug that was causing the
tokenize.untokenize()
function to handle unicode named literals incorrectly. Patch by Pablo Galindogh-114828: Fix compilation crashes in uncommon code examples using
super()
inside a comprehension in a class body.gh-115011: Setters for members with an unsigned integer type now support the same range of valid values for objects that has a
__index__()
method as forint
.gh-112215: Change the C recursion limits to more closely reflect the underlying platform limits.
gh-96497: Fix incorrect resolution of mangled class variables used in assignment expressions in comprehensions.
Library¶
gh-117467: Preserve mailbox ownership when rewriting in
mailbox.mbox.flush()
. Patch by Tony Mountifield.gh-117310: Fixed an unlikely early & extra
Py_DECREF
triggered crash inssl
when creating a new_ssl._SSLContext
if CPython was built implausibly such that the default cipher list is empty or the SSL library it was linked against reports a failure from its CSSL_CTX_set_cipher_list()
API.gh-117178: Fix regression in lazy loading of self-referential modules, introduced in gh-114781.
gh-117084: Fix
zipfile
extraction for directory entries with the name containing backslashes on Windows.gh-117110: Fix a bug that prevents subclasses of
typing.Any
to be instantiated with arguments. Patch by Chris Fu.gh-90872: On Windows,
subprocess.Popen.wait()
no longer callsWaitForSingleObject()
with a negative timeout: pass0
ms if the timeout is negative. Patch by Victor Stinner.gh-116957: configparser: Don't leave ConfigParser values in an invalid state (stored as a list instead of a str) after an earlier read raised DuplicateSectionError or DuplicateOptionError.
gh-90095: Ignore empty lines and comments in
.pdbrc
gh-116764: Restore support of
None
and other false values inurllib.parse
functionsparse_qs()
andparse_qsl()
. Also, they now raise a TypeError for non-zero integers and non-empty sequences.gh-116811: In
PathFinder.invalidate_caches
, delegate toMetadataPathFinder.invalidate_caches
.gh-116484: Change automatically generated
tkinter.Checkbutton
widget names to avoid collisions with automatically generatedtkinter.ttk.Checkbutton
widget names within the same parent widget.gh-116401: Fix blocking
os.fwalk()
andshutil.rmtree()
on opening named pipe.gh-116143: Fix a race in pydoc
_start_server
, eliminating a window in which_start_server
can return a thread that is "serving" but without adocserver
set.gh-116325:
typing
: raiseSyntaxError
instead ofAttributeError
on forward references as empty strings.gh-90535: Fix support of interval values > 1 in
logging.TimedRotatingFileHandler
forwhen='MIDNIGHT'
andwhen='Wx'
.gh-115978: Disable preadv(), readv(), pwritev(), and writev() on WASI.
Under wasmtime for WASI 0.2, these functions don't pass test_posix (https://github.com/bytecodealliance/wasmtime/issues/7830).
gh-88352: Fix the computation of the next rollover time in the
logging.TimedRotatingFileHandler
handler.computeRollover()
now always returns a timestamp larger than the specified time and works correctly during the DST change.doRollover()
no longer overwrite the already rolled over file, saving from data loss when run at midnight or during repeated time at the DST change.gh-87115: Set
__main__.__spec__
toNone
when running a script withpdb
gh-76511: Fix UnicodeEncodeError in
email.Message.as_string()
that results when a message that claims to be in the ascii character set actually has non-ascii characters. Non-ascii characters are now replaced with the U+FFFD replacement character, like in thereplace
error handler.gh-116040: [Enum] fix by-value calls when second value is falsey; e.g. Cardinal(1, 0)
gh-75988: Fixed
unittest.mock.create_autospec()
to pass the call through to the wrapped object to return the real result.gh-115881: Fix issue where
ast.parse()
would incorrectly flag conditional context managers (such aswith (x() if y else z()): ...
) as invalid syntax iffeature_version=(3, 8)
was passed. This reverts changes to the grammar made as part of gh-94949.gh-115886: Fix silent truncation of the name with an embedded null character in
multiprocessing.shared_memory.SharedMemory
.gh-115809: Improve algorithm for computing which rolled-over log files to delete in
logging.TimedRotatingFileHandler
. It is now reliable for handlers withoutnamer
and with arbitrary deterministicnamer
that leaves the datetime part in the file name unmodified.gh-74668:
urllib.parse
functionsparse_qs()
andparse_qsl()
now support bytes arguments containing raw and percent-encoded non-ASCII data.gh-67044:
csv.writer()
now always quotes or escapes'\r'
and'\n'
, regardless of lineterminator value.gh-115712:
csv.writer()
now quotes empty fields if delimiter is a space and skipinitialspace is true and raises exception if quoting is not possible.gh-112364: Fixed
ast.unparse()
to handle format_spec with"
,'
or\\
. Patched by Frank Hoffmann.gh-111358: Fix a bug in
asyncio.BaseEventLoop.shutdown_default_executor()
to ensure the timeout passed to the coroutine behaves as expected.gh-115618: Fix improper decreasing the reference count for
None
argument inproperty
methodsgetter()
,setter()
anddeleter()
.gh-115570: A
DeprecationWarning
is no longer omitted on access to the__doc__
attributes of the deprecatedtyping.io
andtyping.re
pseudo-modules.gh-112006: Fix
inspect.unwrap()
for types with the__wrapper__
data descriptor.gh-101293: Support callables with the
__call__()
method and types with__new__()
and__init__()
methods set to class methods, static methods, bound methods, partial functions, and other types of methods and descriptors ininspect.Signature.from_callable()
.gh-115392: Fix a bug in
doctest
where incorrect line numbers would be reported for decorated functions.gh-114563: Fix several
format()
bugs when using the C implementation ofDecimal
: * memory leak in some rare cases when using thez
format option (coerce negative 0) * incorrect output when applying thez
format option to typeF
(fixed-point with capitalNAN
/INF
) * incorrect output when applying the#
format option (alternate form)gh-115197:
urllib.request
no longer resolves the hostname before checking it against the system's proxy bypass list on macOS and Windows.gh-115165: Most exceptions are now ignored when attempting to set the
__orig_class__
attribute on objects returned when callingtyping
generic aliases (including generic aliases created usingtyping.Annotated
). Previously onlyAttributeError
was ignored. Patch by Dave Shawley.gh-115133: Fix tests for
XMLPullParser
with Expat 2.6.0.gh-115059:
io.BufferedRandom.read1()
now flushes the underlying write buffer.gh-79382: Trailing
**
no longer allows to match files and non-existing paths in recursiveglob()
.gh-114071: Support tuple subclasses using auto() for enum member value.
gh-114763: Protect modules loaded with
importlib.util.LazyLoader
from race conditions when multiple threads try to access attributes before the loading is complete.gh-97959: Fix rendering class methods, bound methods, method and function aliases in
pydoc
. Class methods no longer have "method of builtins.type instance" note. Corresponding notes are now added for class and unbound methods. Method and function aliases now have references to the module or the class where the origin was defined if it differs from the current. Bound methods are now listed in the static methods section. Methods of builtin classes are now supported as well as methods of Python classes.gh-112281: Allow creating union of types for
typing.Annotated
with unhashable metadata.gh-111775: Fix
importlib.resources.simple.ResourceHandle.open()
for text mode, added missedstream
argument.gh-90095: Make .pdbrc and -c work with any valid pdb commands.
gh-107155: Fix incorrect output of
help(x)
wherex
is alambda
function, which has an__annotations__
dictionary attribute with a"return"
key.gh-105866: Fixed
_get_slots
bug which caused error when defining dataclasses with slots and a weakref_slot.gh-60346: Fix ArgumentParser inconsistent with parse_known_args.
gh-100985: Update HTTPSConnection to consistently wrap IPv6 Addresses when using a proxy.
gh-100884: email: fix misfolding of comma in address-lists over multiple lines in combination with unicode encoding.
gh-95782: Fix
io.BufferedReader.tell()
,io.BufferedReader.seek()
,_pyio.BufferedReader.tell()
,io.BufferedRandom.tell()
,io.BufferedRandom.seek()
and_pyio.BufferedRandom.tell()
being able to return negative offsets.gh-96310: Fix a traceback in
argparse
when all options in a mutually exclusive group are suppressed.gh-93205: Fixed a bug in
logging.handlers.TimedRotatingFileHandler
where multiple rotating handler instances pointing to files with the same name but different extensions would conflict and not delete the correct files.bpo-44865: Add missing call to localization function in
argparse
.bpo-43952: Fix
multiprocessing.connection.Listener.accept()
to accept empty bytes as authkey. Not accepting empty bytes as key causes it to hang indefinitely.bpo-42125: linecache: get module name from
__spec__
if available. This allows getting source code for the__main__
module when a custom loader is used.gh-66543: Make
mimetypes.guess_type()
properly parsing of URLs with only a host name, URLs containing fragment or query, and filenames with only a UNC sharepoint on Windows. Based on patch by Dong-hee Na.bpo-33775: Add 'default' and 'version' help text for localization in argparse.
Documentation¶
gh-115399: Document CVE 2023-52425 of Expat <2.6.0 under "XML vulnerabilities".
gh-115233: Fix an example for
LoggerAdapter
in the Logging Cookbook.
Tests¶
gh-83434: Disable JUnit XML output (
--junit-xml=FILE
command line option) in regrtest when hunting for reference leaks (-R
option). Patch by Victor Stinner.gh-117187: Fix XML tests for vanilla Expat <2.6.0.
gh-116333: Tests of TLS related things (error codes, etc) were updated to be more lenient about specific error message strings and behaviors as seen in the BoringSSL and AWS-LC forks of OpenSSL.
gh-115979: Update test_importlib so that it passes under WASI SDK 21.
gh-112536: Add --tsan to test.regrtest for running TSAN tests in reasonable execution times. Patch by Donghee Na.
gh-116307: Added import helper
isolated_modules
asCleanImport
does not remove modules imported during the context. Use it in importlib.resources tests to avoid leavingmod
around to impede importlib.metadata tests.gh-115720: Leak tests (
-R
,--huntrleaks
) now show a summary of the number of leaks found in each iteration.gh-115122: Add
--bisect
option to regrtest test runner: run failed tests withtest.bisect_cmd
to identify failing tests. Patch by Victor Stinner.gh-115596: Fix
ProgramPriorityTests
intest_os
permanently changing the process priority.
Build¶
gh-116313: Get WASI builds to work under wasmtime 18 w/ WASI 0.2/preview2 primitives.
gh-116117: Backport
libb2
's PR #42 to fix compiling CPython on 32-bit Windows withclang-cl
.gh-115167: Avoid vendoring
vcruntime140_threads.dll
when building with Visual Studio 2022 version 17.8.gh-112536: Add support for thread sanitizer (TSAN)
Windows¶
gh-117267: Ensure
DirEntry.stat().st_ctime
behaves consistently withos.stat()
during the deprecation period ofst_ctime
by containing the same value asst_birthtime
. After the deprecation period,st_ctime
will be the metadata change time (or unavailable throughDirEntry
), and onlyst_birthtime
will contain the creation time.gh-116773: Fix instances of
<_overlapped.Overlapped object at 0xXXX> still has pending operation at deallocation, the process may crash
.gh-91227: Fix the asyncio ProactorEventLoop implementation so that sending a datagram to an address that is not listening does not prevent receiving any more datagrams.
gh-115554: The installer now has more strict rules about updating the Lanceur Python pour Windows. In general, most users only have a single launcher installed and will see no difference. When multiple launchers have been installed, the option to install the launcher is disabled until all but one have been removed. Downgrading the launcher (which was never allowed) is now more obviously blocked.
gh-115543: Lanceur Python pour Windows can now detect Python 3.13 when installed from the Microsoft Store, and will install Python 3.12 by default when
PYLAUNCHER_ALLOW_INSTALL
is set.gh-115049: Fixes
py.exe
launcher failing when run as users without user profiles.gh-115009: Update Windows installer to use SQLite 3.45.1.
IDLE¶
gh-88516: On macOS show a proxy icon in the title bar of editor windows to match platform behaviour.
Tools/Demos¶
gh-113516: Don't set
LDSHARED
when building for WASI.
C API¶
Python 3.12.2 final¶
Release date: 2024-02-06
Security¶
gh-113659: Skip
.pth
files with names starting with a dot or hidden file attribute.
Core and Builtins¶
gh-114887: Changed socket type validation in
create_datagram_endpoint()
to accept all non-stream sockets. This fixes a regression in compatibility with raw sockets.gh-114388: Fix a
RuntimeWarning
emitted when assign an integer-like value that is not an instance ofint
to an attribute that corresponds to a C struct member of type T_UINT and T_ULONG. Fix a doubleRuntimeWarning
emitted when assign a negative integer value to an attribute that corresponds to a C struct member of type T_UINT.gh-113703: Fix a regression in the
codeop
module that was causing it to incorrectly identify incomplete f-strings. Patch by Pablo Galindogh-89811: Check for a valid
tp_version_tag
before performing bytecode specializations that rely on this value being usable.gh-113602: Fix an error that was causing the parser to try to overwrite existing errors and crashing in the process. Patch by Pablo Galindo
gh-113297: Fix segfault in the compiler on with statement with 19 context managers.
gh-106905: Use per AST-parser state rather than global state to track recursion depth within the AST parser to prevent potential race condition due to simultaneous parsing.
The issue primarily showed up in 3.11 by multithreaded users of
ast.parse()
. In 3.12 a change to when garbage collection can be triggered prevented the race condition from occurring.gh-112943: Correctly compute end column offsets for multiline tokens in the
tokenize
module. Patch by Pablo Galindogh-112716: Fix SystemError in the
import
statement and in__reduce__()
methods of builtin types when__builtins__
is not a dict.gh-94606: Fix UnicodeEncodeError when
email.message.get_payload()
reads a message with a Unicode surrogate character and the message content is not well-formed for surrogateescape encoding. Patch by Sidney Markowitz.
Library¶
gh-114965: Update bundled pip to 24.0
gh-114959:
tarfile
no longer ignores errors when trying to extract a directory on top of a file.gh-109475: Fix support of explicit option value "--" in
argparse
(e.g.--option=--
).gh-110190: Fix ctypes structs with array on Windows ARM64 platform by setting
MAX_STRUCT_SIZE
to 32 in stgdict. Patch by Diego Russogh-113280: Fix a leak of open socket in rare cases when error occurred in
ssl.SSLSocket
creation.gh-77749:
email.policy.EmailPolicy.fold()
now always encodes non-ASCII characters in headers ifutf8
is false.gh-114492: Make the result of
termios.tcgetattr()
reproducible on Alpine Linux. Previously it could leave a random garbage in some fields.gh-113267: Revert changes in gh-106584 which made calls of
TestResult
methodsstartTest()
andstopTest()
unbalanced.gh-75128: Ignore an
OSError
inasyncio.BaseEventLoop.create_server()
when IPv6 is available but the interface cannot actually support it.gh-114257: Dismiss the
FileNotFound
error inctypes.util.find_library()
and just returnNone
on Linux.gh-114328: The
tty.setcbreak()
and newtty.cfmakecbreak()
no longer clears the terminal input ICRLF flag. This fixes a regression introduced in 3.12 that no longer matched how OSes define cbreak mode in theirstty(1)
manual pages.gh-101438: Avoid reference cycle in ElementTree.iterparse. The iterator returned by
ElementTree.iterparse
may hold on to a file descriptor. The reference cycle prevented prompt clean-up of the file descriptor if the returned iterator was not exhausted.gh-104522:
OSError
raised when run a subprocess now only has filename attribute set to cwd if the error was caused by a failed attempt to change the current directory.gh-114149: Enum: correctly handle tuple subclasses in custom
__new__
.gh-109534: Fix a reference leak in
asyncio.selector_events.BaseSelectorEventLoop
when SSL handshakes fail. Patch contributed by Jamie Phan.gh-114077: Fix possible
OverflowError
insocket.socket.sendfile()
when pass count larger than 2 GiB on 32-bit platform.gh-114014: Fixed a bug in
fractions.Fraction
where an invalid string usingd
in the decimals part creates a different error compared to other invalid letters/characters. Patch by Jeremiah Gabriel Pascual.gh-113951: Fix the behavior of
tag_unbind()
methods oftkinter.Text
andtkinter.Canvas
classes with three arguments. Previously,widget.tag_unbind(tag, sequence, funcid)
destroyed the current binding for sequence, leaving sequence unbound, and deleted the funcid command. Now it removes only funcid from the binding for sequence, keeping other commands, and deletes the funcid command. It leaves sequence unbound only if funcid was the last bound command.gh-113877: Fix
tkinter
methodwinfo_pathname()
on 64-bit Windows.gh-113661: unittest runner: Don't exit 5 if tests were skipped. The intention of exiting 5 was to detect issues where the test suite wasn't discovered at all. If we skipped tests, it was correctly discovered.
gh-113781: Silence unraisable AttributeError when warnings are emitted during Python finalization.
gh-112932: Restore the ability for
zipfile
toextractall
from zip files with a "/" directory entry in them as is commonly added to zips by some wiki or bug tracker data exporters.gh-113594: Fix
UnicodeEncodeError
inemail
when re-fold lines that contain unknown-8bit encoded part followed by non-unknown-8bit encoded part.gh-113538: In
asyncio.StreamReaderProtocol.connection_made()
, there is callback that logs an error if the task wrapping the "connected callback" fails. This callback would itself fail if the task was cancelled. Prevent this by checking whether the task was cancelled first. If so, close the transport but don't log an error.gh-85567: Fix resource warnings for unclosed files in
pickle
andpickletools
command line interfaces.gh-101225: Increase the backlog for
multiprocessing.connection.Listener
objects created bymultiprocessing.manager
andmultiprocessing.resource_sharer
to significantly reduce the risk of getting a connection refused error when creating amultiprocessing.connection.Connection
to them.gh-113543: Make sure that
webbrowser.MacOSXOSAScript
sendswebbrowser.open
audit event.gh-113028: When a second reference to a string appears in the input to
pickle
, and the Python implementation is in use, we are guaranteed that a single copy gets pickled and a single object is shared when reloaded. Previously, in protocol 0, when a string contained certain characters (e.g. newline) it resulted in duplicate objects.gh-113421: Fix multiprocessing logger for
%(filename)s
.gh-111784: Fix segfaults in the
_elementtree
module. Fix first segfault during deallocation of_elementtree.XMLParser
instances by keeping strong reference topyexpat
module in module state for capsule lifetime. Fix second segfault which happens in the same deallocation process by keeping strong reference to_elementtree
module inXMLParser
structure for_elementtree
module lifetime.gh-113407: Fix import of
unittest.mock
when CPython is built without docstrings.gh-113320: Fix regression in Python 3.12 where
Protocol
classes that were not marked asruntime-checkable
would be unnecessarily introspected, potentially causing exceptions to be raised if the protocol had problematic members. Patch by Alex Waygood.gh-113358: Fix rendering tracebacks for exceptions with a broken
__getattr__
.gh-113214: Fix an
AttributeError
during asyncio SSL protocol aborts in SSL-over-SSL scenarios.gh-113246: Update bundled pip to 23.3.2.
gh-113199: Make
http.client.HTTPResponse.read1
andhttp.client.HTTPResponse.readline
close IO after reading all data when content length is known. Patch by Illia Volochii.gh-113188: Fix
shutil.copymode()
andshutil.copystat()
on Windows. Previously they worked differenly if dst is a symbolic link: they modified the permission bits of dst itself rather than the file it points to if follow_symlinks is true or src is not a symbolic link, and did not modify the permission bits if follow_symlinks is false and src is a symbolic link.gh-61648: Detect line numbers of properties in doctests.
gh-112559:
signal.signal()
andsignal.getsignal()
no longer callrepr
on callable handlers.asyncio.run()
andasyncio.Runner.run()
no longer callrepr
on the task results. Patch by Yilei Yang.gh-110190: Fix ctypes structs with array on PPC64LE platform by setting
MAX_STRUCT_SIZE
to 64 in stgdict. Patch by Diego Russo.gh-79429: Ignore FileNotFoundError when remove a temporary directory in the multiprocessing finalizer.
gh-81194: Fix a crash in
socket.if_indextoname()
with specific value (UINT_MAX). Fix an integer overflow insocket.if_indextoname()
on 64-bit non-Windows platforms.gh-112343: Improve handling of pdb convenience variables to avoid replacing string contents.
gh-111615: Fix a regression caused by a fix to gh-93162 whereby you couldn't configure a
QueueHandler
without specifying handlers.gh-111049: Fix crash during garbage collection of the
io.BytesIO
buffer object.gh-110345: Show the Tcl/Tk patchlevel (rather than version) in
tkinter._test()
.gh-109858: Protect
zipfile
from "quoted-overlap" zipbomb. It now raises BadZipFile when try to read an entry that overlaps with other entry or central directory.gh-114440: On Windows, closing the connection writer when cleaning up a broken
multiprocessing.Queue
queue is now done for all queues, rather than only inconcurrent.futures
manager thread. This can prevent a deadlock when amultiprocessing
worker process terminates without cleaning up. This completes the backport of patches by Victor Stinner and Serhiy Storchaka.gh-38807: Fix race condition in
trace
. Instead of checking if a directory exists and creating it, directly callos.makedirs()
with the kwargexist_ok=True
.gh-75705: Set unixfrom envelope in
mailbox.mbox
andmailbox.MMDF
.gh-106233: Fix stacklevel in
InvalidTZPathWarning
duringzoneinfo
module import.gh-105102: Allow
ctypes.Union
to be nested inctypes.Structure
when the system endianness is the opposite of the classes.gh-104282: Fix null pointer dereference in
lzma._decode_filter_properties()
due to improper handling of BCJ filters with properties of zero length. Patch by Radislav Chugunov.gh-102512: When
os.fork()
is called from a foreign thread (aka_DummyThread
), the type of the thread in a child process is changed to_MainThread
. Also changed its name and daemonic status, it can be now joined.bpo-35928:
io.TextIOWrapper
now correctly handles the decoding buffer afterread()
andwrite()
.bpo-26791:
shutil.move()
now moves a symlink into a directory when that directory is the target of the symlink. This provides the same behavior as the mv shell command. The previous behavior raised an exception. Patch by Jeffrey Kintscher.bpo-36959: Fix some error messages for invalid ISO format string combinations in
strptime()
that referred to directives not contained in the format string. Patch by Gordon P. Hemsley.bpo-18060: Fixed a class inheritance issue that can cause segfaults when deriving two or more levels of subclasses from a base class of Structure or Union.
Documentation¶
gh-110746: Improved markup for valid options/values for methods ttk.treeview.column and ttk.treeview.heading, and for Layouts.
gh-95649: Document that the
asyncio
module contains code taken from v0.16.0 of the uvloop project, as well as the required MIT licensing information.
Tests¶
gh-109980: Fix
test_tarfile_vs_tar
intest_shutil
for macOS, where system tar can include more information in the archive thanshutil.make_archive
.gh-105089: Fix
test.test_zipfile.test_core.TestWithDirectory.test_create_directory_with_write
test in AIX by doing a bitwise AND of 0xFFFF on mode , so that it will be in sync withzinfo.external_attr
bpo-40648: Test modes that file can get with chmod() on Windows.
Build¶
gh-112305: Fixed the
check-clean-src
step performed on out of tree builds to detect errant$(srcdir)/Python/frozen_modules/*.h
files and recommend appropriate source tree cleanup steps to get a working build again.gh-112867: Fix the build for the case that WITH_PYMALLOC_RADIX_TREE=0 set.
bpo-11102: The
os.major()
,os.makedev()
, andos.minor()
functions are now available on HP-UX v3.bpo-36351: Do not set ipv6type when cross-compiling.
Windows¶
gh-109991: Update Windows build to use OpenSSL 3.0.13.
gh-111239: Update Windows builds to use zlib v1.3.1.
gh-100107: The
py.exe
launcher will no longer attempt to run the Microsoft Store redirector when launching a script containing a/usr/bin/env
shebanggh-114096: Process privileges that are activated for creating directory junctions are now restored afterwards, avoiding behaviour changes in other parts of the program.
gh-111877:
os.stat()
calls were returning incorrect time values for files that could not be accessed directly.gh-113009:
multiprocessing
: On Windows, fix a race condition inProcess.terminate()
: no longer set thereturncode
attribute to always callWaitForSingleObject()
inProcess.wait()
. Previously, sometimes the process was still running afterTerminateProcess()
even ifGetExitCodeProcess()
is notSTILL_ACTIVE
. Patch by Victor Stinner.gh-87868: Correctly sort and remove duplicate environment variables in
_winapi.CreateProcess()
.bpo-37308: Fix mojibake in
mmap.mmap
when using a non-ASCII tagname argument on Windows.
macOS¶
gh-115009: Update macOS installer to use SQLite 3.45.1.
gh-109991: Update macOS installer to use OpenSSL 3.0.13.
gh-110459: Running
configure ... --with-openssl-rpath=X/Y/Z
no longer fails to detect OpenSSL on macOS.gh-74573: Document that
dbm.ndbm
can silently corrupt DBM files on updates when exceeding undocumented platform limits, and can crash (segmentation fault) when reading such a corrupted file. (FB8919203)gh-65701: The freeze tool doesn't work with framework builds of Python. Document this and bail out early when running the tool with such a build.
gh-108269: Set
CFBundleAllowMixedLocalizations
to true in the Info.plist for the framework, embedded Python.app and IDLE.app with framework installs on macOS. This allows applications to pick up the user's preferred locale when that's different from english.gh-102362: Make sure the result of
sysconfig.get_plaform()
includes at least a major and minor versions, even ifMACOSX_DEPLOYMENT_TARGET
is set to only a major version during build to match the format expected by pip.gh-110017: Disable a signal handling stress test on macOS due to a bug in macOS (FB13453490).
gh-110820: Make sure the preprocessor definitions for
ALIGNOF_MAX_ALIGN_T
,SIZEOF_LONG_DOUBLE
andHAVE_GCC_ASM_FOR_X64
are correct for Universal 2 builds on macOS.
IDLE¶
gh-96905: In idlelib code, stop redefining built-ins 'dict' and 'object'.
gh-72284: Improve the lists of features, editor key bindings, and shell key bingings in the IDLE doc.
gh-113903: Fix rare failure of test.test_idle, in test_configdialog.
gh-113729: Fix the "Help -> IDLE Doc" menu bug in 3.11.7 and 3.12.1.
gh-113269: Fix test_editor hang on macOS Catalina.
gh-112898: Fix processing unsaved files when quitting IDLE on macOS.
gh-103820: Revise IDLE bindings so that events from mouse button 4/5 on non-X11 windowing systems (i.e. Win32 and Aqua) are not mistaken for scrolling.
bpo-13586: Enter the selected text when opening the "Replace" dialog.
Tools/Demos¶
gh-109991: Update GitHub CI workflows to use OpenSSL 3.0.13 and multissltests to use 1.1.1w, 3.0.13, 3.1.5, and 3.2.1.
gh-115015: Fix a bug in Argument Clinic that generated incorrect code for methods with no parameters that use the METH_METHOD | METH_FASTCALL | METH_KEYWORDS calling convention. Only the positional parameter count was checked; any keyword argument passed would be silently accepted.
Python 3.12.1 final¶
Release date: 2023-12-07
Core and Builtins¶
gh-112125: Fix None.__ne__(None) returning NotImplemented instead of False
gh-112625: Fixes a bug where a bytearray object could be cleared while iterating over an argument in the
bytearray.join()
method that could result in reading memory after it was freed.gh-105967: Workaround a bug in Apple's macOS platform zlib library where
zlib.crc32()
andbinascii.crc32()
could produce incorrect results on multi-gigabyte inputs. Including when usingzipfile
on zips containing large data.gh-112356: Stopped erroneously deleting a
LOAD_NULL
bytecode instruction when optimized twice.gh-111058: Change coro.cr_frame/gen.gi_frame to return
None
after the coroutine/generator has been closed. This fixes a bug wheregetcoroutinestate()
andgetgeneratorstate()
return the wrong state for a closed coroutine/generator.gh-112388: Fix an error that was causing the parser to try to overwrite tokenizer errors. Patch by pablo Galindo
gh-112387: Fix error positions for decoded strings with backwards tokenize errors. Patch by Pablo Galindo
gh-112367: Avoid undefined behaviour when using the perf trampolines by not freeing the code arenas until shutdown. Patch by Pablo Galindo
gh-112243: Don't include comments in f-string debug expressions. Patch by Pablo Galindo
gh-111654: Fix runtime crash when some error happens in opcode
LOAD_FROM_DICT_OR_DEREF
.gh-109181: Speed up
Traceback
object creation by lazily compute the line number. Patch by Pablo Galindogh-102388: Fix a bug where
iso2022_jp_3
andiso2022_jp_2004
codecs read out of boundsgh-111366: Fix an issue in the
codeop
that was causingSyntaxError
exceptions raised in the presence of invalid syntax to not contain precise error messages. Patch by Pablo Galindogh-111380: Fix a bug that was causing
SyntaxWarning
to appear twice when parsing if invalid syntax is encountered later. Patch by Pablo galindogh-94438: Fix a regression that prevented jumping across
is None
andis not None
when debugging. Patch by Savannah Ostrowski.gh-110938: Fix error messages for indented blocks with functions and classes with generic type parameters. Patch by Pablo Galindo
gh-109894: Fixed crash due to improperly initialized static
MemoryError
in subinterpreter.gh-110782: Fix crash when
typing.TypeVar
is constructed with a keyword argument. Patch by Jelle Zijlstra.gh-110696: Fix incorrect error message for invalid argument unpacking. Patch by Pablo Galindo
gh-110543: Fix regression in Python 3.12 where
types.CodeType.replace()
would produce a broken code object if called on a module or class code object that contains a comprehension. Patch by Jelle Zijlstra.gh-110514: Add
PY_THROW
tosys.setprofile()
eventsgh-110455: Guard
assert(tstate->thread_id > 0)
with#ifndef HAVE_PTHREAD_STUBS
. This allows for for pydebug builds to work under WASI which (currently) lacks thread support.gh-110259: Correctly identify the format spec in f-strings (with single or triple quotes) that have multiple lines in the expression part and include a formatting spec. Patch by Pablo Galindo
gh-110237: Fix missing error checks for calls to
PyList_Append
in_PyEval_MatchClass
.gh-109889: Fix the compiler's redundant NOP detection algorithm to skip over NOPs with no line number when looking for the next instruction's lineno.
gh-109853:
sys.path[0]
is now set correctly for subinterpreters.gh-105716: Subinterpreters now correctly handle the case where they have threads running in the background. Before, such threads would interfere with cleaning up and destroying them, as well as prevent running another script.
gh-109793: The main thread no longer exits prematurely when a subinterpreter is cleaned up during runtime finalization. The bug was a problem particularly because, when triggered, the Python process would always return with a 0 exitcode, even if it failed.
gh-109596: Fix some tokens in the grammar that were incorrectly marked as soft keywords. Also fix some repeated rule names and ensure that repeated rules are not allowed. Patch by Pablo Galindo
gh-109351: Fix crash when compiling an invalid AST involving a named (walrus) expression.
gh-109207: Fix a SystemError in
__repr__
of symtable entry object.gh-109179: Fix bug where the C traceback display drops notes from
SyntaxError
.gh-109052: Use the base opcode when comparing code objects to avoid interference from instrumentation
gh-88943: Improve syntax error for non-ASCII character that follows a numerical literal. It now points on the invalid non-ASCII character, not on the valid numerical literal.
gh-106931: Statically allocated string objects are now interned globally instead of per-interpreter. This fixes a situation where such a string would only be interned in a single interpreter. Normal string objects are unaffected.
Library¶
gh-79325: Fix an infinite recursion error in
tempfile.TemporaryDirectory()
cleanup on Windows.gh-112645: Remove deprecation error on passing
onerror
toshutil.rmtree()
.gh-112618: Fix a caching bug relating to
typing.Annotated
.Annotated[str, True]
is no longer identical toAnnotated[str, 1]
.gh-112334: Fixed a performance regression in 3.12's
subprocess
on Linux where it would no longer use the fast-pathvfork()
system call when it should have due to a logic bug, instead always falling back to the safe but slowerfork()
.Also fixed a related 3.12 security regression: If a value of
extra_groups=[]
was passed tosubprocess.Popen
or related APIs, the underlyingsetgroups(0, NULL)
system call to clear the groups list would not be made in the child process prior toexec()
. This has been assigned CVE 2023-6507.This was identified via code inspection in the process of fixing the first bug.
gh-110190: Fix ctypes structs with array on Arm platform by setting
MAX_STRUCT_SIZE
to 32 in stgdict. Patch by Diego Russo.gh-112578: Fix a spurious
RuntimeWarning
when executing thezipfile
module.gh-112509: Fix edge cases that could cause a key to be present in both the
__required_keys__
and__optional_keys__
attributes of atyping.TypedDict
. Patch by Jelle Zijlstra.gh-112414: Fix regression in Python 3.12 where calling
repr()
on a module that had been imported using a custom loader could fail withAttributeError
. Patch by Alex Waygood.gh-112358: Revert change to
struct.Struct
initialization that broke some cases of subclassing.gh-94722: Fix bug where comparison between instances of
DocTest
fails if one of them hasNone
as its lineno.gh-112105: Make
readline.set_completer_delims()
work with libeditgh-111942: Fix SystemError in the TextIOWrapper constructor with non-encodable "errors" argument in non-debug mode.
gh-109538: Issue warning message instead of having
RuntimeError
be displayed when event loop has already been closed atStreamWriter.__del__()
.gh-111942: Fix crashes in
io.TextIOWrapper.reconfigure()
when pass invalid arguments, e.g. non-string encoding.gh-111460:
curses
: restore wide character support (includingcurses.unget_wch()
andget_wch()
) on macOS, which was unavailable due to a regression in Python 3.12.gh-103791:
contextlib.suppress
now supports suppressing exceptions raised as part of aBaseExceptionGroup
, in addition to the recent support forExceptionGroup
.gh-111804: Remove posix.fallocate() under WASI as the underlying posix_fallocate() is not available in WASI preview2.
gh-111841: Fix truncating arguments on an embedded null character in
os.putenv()
andos.unsetenv()
on Windows.gh-111541: Fix
doctest
forSyntaxError
not-builtin subclasses.gh-110894: Call loop exception handler for exceptions in
client_connected_cb
ofasyncio.start_server()
so that applications can handle it. Patch by Kumar Aditya.gh-111531: Fix reference leaks in
bind_class()
andbind_all()
methods oftkinter
widgets.gh-111356: Added
io.text_encoding()
,io.DEFAULT_BUFFER_SIZE
, andio.IncrementalNewlineDecoder
toio.__all__
.gh-111342: Fixed typo in
math.sumprod()
.gh-68166: Remove mention of not supported "vsapi" element type in
tkinter.ttk.Style.element_create()
. Add tests forelement_create()
and otherttk.Style
methods. Add examples forelement_create()
in the documentation.gh-75666: Fix the behavior of
tkinter
widget'sunbind()
method with two arguments. Previously,widget.unbind(sequence, funcid)
destroyed the current binding for sequence, leaving sequence unbound, and deleted the funcid command. Now it removes only funcid from the binding for sequence, keeping other commands, and deletes the funcid command. It leaves sequence unbound only if funcid was the last bound command.gh-79033: Another attempt at fixing
asyncio.Server.wait_closed()
. It now blocks until both conditions are true: the server is closed, and there are no more active connections. (This means that in some cases where in 3.12.0 this function would incorrectly have returned immediately, it will now block; in particular, when there are no active connections but the server hasn't been closed yet.)gh-111295: Fix
time
not checking for errors when initializing.gh-111253: Add error checking during
_socket
module init.gh-111251: Fix
_blake2
not checking for errors when initializing.gh-111174: Fix crash in
io.BytesIO.getbuffer()
called repeatedly for empty BytesIO.gh-111187: Postpone removal version for locale.getdefaultlocale() to Python 3.15.
gh-111159: Fix
doctest
output comparison for exceptions with notes.gh-110910: Fix invalid state handling in
asyncio.TaskGroup
andasyncio.Timeout
. They now raise proper RuntimeError if they are improperly used and are left in consistent state after this.gh-111092: Make turtledemo run without default root enabled.
gh-110488: Fix a couple of issues in
pathlib.PurePath.with_name()
: a single dot was incorrectly considered a valid name, and inPureWindowsPath
, a name with an NTFS alternate data stream, likea:b
, was incorrectly considered invalid.gh-110392: Fix
tty.setraw()
andtty.setcbreak()
: previously they returned partially modified list of the original tty attributes.tty.cfmakeraw()
andtty.cfmakecbreak()
now make a copy of the list of special characters before modifying it.gh-110590: Fix a bug in
_sre.compile()
whereTypeError
would be overwritten byOverflowError
when the code argument was a list of non-ints.gh-65052: Prevent
pdb
from crashing when trying to display undisplayable objectsgh-110519: Deprecation warning about non-integer number in
gettext
now alwais refers to the line in the user code where gettext function or method is used. Previously it could refer to a line ingettext
code.gh-110395: Ensure that
select.kqueue()
objects correctly appear as closed in forked children, to prevent operations on an invalid file descriptor.gh-110378:
contextmanager()
andasynccontextmanager()
context managers now close an invalid underlying generator object that yields more then one value.gh-110365: Fix
termios.tcsetattr()
bug that was overwritting existing errors during parsing integers fromterm
list.gh-109653: Fix a Python 3.12 regression in the import time of
random
. Patch by Alex Waygood.gh-110196: Add
__reduce__
method toIPv6Address
in order to keepscope_id
gh-110036: On Windows, multiprocessing
Popen.terminate()
now catchsPermissionError
and get the process exit code. If the process is still running, raise again thePermissionError
. Otherwise, the process terminated as expected: store its exit code. Patch by Victor Stinner.gh-110038: Fixed an issue that caused
KqueueSelector.select()
to not return all the ready events in some cases when a file descriptor is registered for both read and write.gh-109631:
re
functions such asre.findall()
,re.split()
,re.search()
andre.sub()
which perform short repeated matches can now be interrupted by user.gh-109747: Improve errors for unsupported look-behind patterns. Now re.error is raised instead of OverflowError or RuntimeError for too large width of look-behind pattern.
gh-109818: Fix
reprlib.recursive_repr()
not copying__type_params__
from decorated function.gh-109047:
concurrent.futures
: The executor manager thread now catches exceptions when adding an item to the call queue. During Python finalization, creating a new thread can now raiseRuntimeError
. Catch the exception and callterminate_broken()
in this case. Patch by Victor Stinner.gh-109782: Ensure the signature of
os.path.isdir()
is identical on all platforms. Patch by Amin Alaee.gh-109590:
shutil.which()
will prefer files with an extension inPATHEXT
if the given mode includesos.X_OK
on win32. If noPATHEXT
match is found, a file without an extension inPATHEXT
can be returned. This change will haveshutil.which()
act more similarly to previous behavior in Python 3.11.gh-109786: Fix possible reference leaks and crash when re-enter the
__next__()
method ofitertools.pairwise
.gh-109593: Avoid deadlocking on a reentrant call to the multiprocessing resource tracker. Such a reentrant call, though unlikely, can happen if a GC pass invokes the finalizer for a multiprocessing object such as SemLock.
gh-109613: Fix
os.stat()
andos.DirEntry.stat()
: check for exceptions. Previously, on Python built in debug mode, these functions could trigger a fatal Python error (and abort the process) when a function succeeded with an exception set. Patch by Victor Stinner.gh-109375: The
pdb
alias
command now prevents registering aliases without arguments.gh-107219: Fix a race condition in
concurrent.futures
. When a process in the process pool was terminated abruptly (while the future was running or pending), close the connection write end. If the call queue is blocked on sending bytes to a worker process, closing the connection write end interrupts the send, so the queue can be closed. Patch by Victor Stinner.gh-50644: Attempts to pickle or create a shallow or deep copy of
codecs
streams now raise a TypeError. Previously, copying failed with a RecursionError, while pickling produced wrong results that eventually caused unpickling to fail with a RecursionError.gh-108987: Fix
_thread.start_new_thread()
race condition. If a thread is created during Python finalization, the newly spawned thread now exits immediately instead of trying to access freed memory and lead to a crash. Patch by Victor Stinner.gh-108791: Improved error handling in
pdb
command line interface, making it produce more concise error messages.gh-105829: Fix concurrent.futures.ProcessPoolExecutor deadlock
gh-106584: Fix exit code for
unittest
if all tests are skipped. Patch by Egor Eliseev.gh-102956: Fix returning of empty byte strings after seek in zipfile module
gh-84867:
unittest.TestLoader
no longer loads test cases from exactunittest.TestCase
andunittest.FunctionTestCase
classes.gh-91133: Fix a bug in
tempfile.TemporaryDirectory
cleanup, which now no longer dereferences symlinks when working around file system permission errors.gh-73561: Omit the interface scope from an IPv6 address when used as Host header by
http.client
.gh-86826:
zipinfo
now supports the full range of values in the TZ string determined by RFC 8536 and detects all invalid formats. Both Python and C implementations now raise exceptions of the same type on invalid data.bpo-43153: On Windows,
tempfile.TemporaryDirectory
previously masked aPermissionError
withNotADirectoryError
during directory cleanup. It now correctly raisesPermissionError
if errors are not ignored. Patch by Andrei Kulakov and Ken Jin.bpo-35332: The
shutil.rmtree()
function now ignores errors when callingos.close()
when ignore_errors isTrue
, andos.close()
no longer retried after error.bpo-41422: Fixed memory leaks of
pickle.Pickler
andpickle.Unpickler
involving cyclic references via the internal memo mapping.bpo-40262: The
ssl.SSLSocket.recv_into()
method no longer requires the buffer argument to implement__len__
and supports buffers with arbitrary item size.
Documentation¶
Tests¶
gh-112769: The tests now correctly compare zlib version when
zlib.ZLIB_RUNTIME_VERSION
contains non-integer suffixes. For example zlib-ng defines the version as1.3.0.zlib-ng
.gh-110367: Make regrtest
--verbose3
option compatible with--huntrleaks -jN
options. The./python -m test -j1 -R 3:3 --verbose3
command now works as expected. Patch by Victor Stinner.gh-111165: Remove no longer used functions
run_unittest()
andrun_doctest()
from thetest.support
module.gh-110932: Fix regrtest if the
SOURCE_DATE_EPOCH
environment variable is defined: use the variable value as the random seed. Patch by Victor Stinner.gh-110995: test_gdb: Fix detection of gdb built without Python scripting support. Patch by Victor Stinner.
gh-110918: Test case matching patterns specified by options
--match
,--ignore
,--matchfile
and--ignorefile
are now tested in the order of specification, and the last match determines whether the test case be run or ignored.gh-110647: Fix test_stress_modifying_handlers() of test_signal. Patch by Victor Stinner.
gh-103053: Fix test_tools.test_freeze on FreeBSD: run "make distclean" instead of "make clean" in the copied source directory to remove also the "python" program. Patch by Victor Stinner.
gh-110167: Fix a deadlock in test_socket when server fails with a timeout but the client is still running in its thread. Don't hold a lock to call cleanup functions in doCleanups(). One of the cleanup function waits until the client completes, whereas the client could deadlock if it called addCleanup() in such situation. Patch by Victor Stinner.
gh-110267: Add tests for pickling and copying PyStructSequence objects. Patched by Xuehai Pan.
gh-110031: Skip test_threading tests using thread+fork if Python is built with Address Sanitizer (ASAN). Patch by Victor Stinner.
gh-110088: Fix test_asyncio timeouts: don't measure the maximum duration, a test should not measure a CI performance. Only measure the minimum duration when a task has a timeout or delay. Add
CLOCK_RES
totest_asyncio.utils
. Patch by Victor Stinner.gh-109974: Fix race conditions in test_threading lock tests. Wait until a condition is met rather than using
time.sleep()
with a hardcoded number of seconds. Patch by Victor Stinner.gh-110033: Fix
test_interprocess_signal()
oftest_signal
. Make sure that thesubprocess.Popen
object is deleted before the test raising an exception in a signal handler. Otherwise,Popen.__del__()
can get the exception which is logged asException ignored in: ...
and the test fails. Patch by Victor Stinner.gh-109594: Fix test_timeout() of test_concurrent_futures.test_wait. Remove the future which may or may not complete depending if it takes longer than the timeout ot not. Keep the second future which does not complete before wait() timeout. Patch by Victor Stinner.
gh-109972: Split test_gdb.py file into a test_gdb package made of multiple tests, so tests can now be run in parallel. Patch by Victor Stinner.
gh-103053: Skip test_freeze_simple_script() of test_tools.test_freeze if Python is built with
./configure --enable-optimizations
, which means with Profile Guided Optimization (PGO): it just makes the test too slow. The freeze tool is tested by many other CIs with other (faster) compiler flags. Patch by Victor Stinner.gh-109580: Skip
test_perf_profiler
if Python is built with ASAN, MSAN or UBSAN sanitizer. Python does crash randomly in this test on such build. Patch by Victor Stinner.gh-104736: Fix test_gdb on Python built with LLVM clang 16 on Linux ppc64le (ex: Fedora 38). Search patterns in gdb "bt" command output to detect when gdb fails to retrieve the traceback. For example, skip a test if
Backtrace stopped: frame did not save the PC
is found. Patch by Victor Stinner.gh-108927: Fixed order dependence in running tests in the same process when a test that has submodules (e.g. test_importlib) follows a test that imports its submodule (e.g. test_importlib.util) and precedes a test (e.g. test_unittest or test_compileall) that uses that submodule.
Build¶
gh-112088: Add
Tools/build/regen-configure.sh
script to regenerate theconfigure
with an Ubuntu container image. Thequay.io/tiran/cpython_autoconf:271
container image (tiran/cpython_autoconf) is no longer used. Patch by Victor Stinner.gh-111046: For wasi-threads, memory is now exported to fix compatibility issues with some wasm runtimes.
gh-103053: "make check-clean-src" now also checks if the "python" program is found in the source directory: fail with an error if it does exist. Patch by Victor Stinner.
gh-109191: Fix compile error when building with recent versions of libedit.
Windows¶
gh-111856: Fixes
fstat()
on file systems that do not support file ID requests. This includes FAT32 and exFAT.gh-111293: Fix
os.DirEntry.inode
dropping higher 64 bits of a file id on some filesystems on Windows.gh-110913: WindowsConsoleIO now correctly chunks large buffers without splitting up UTF-8 sequences.
gh-110437: Allows overriding the source of VC redistributables so that releases can be guaranteed to never downgrade between updates.
gh-109286: Update Windows installer to use SQLite 3.43.1.
macOS¶
gh-109981: Use
/dev/fd
on macOS to determine the number of open files intest.support.os_helper.fd_count
to avoid a crash with "guarded" file descriptors when probing for open files.gh-110950: Update macOS installer to include an upstream Tcl/Tk fix for the
Secure coding is not enabled for restorable state!
warning encountered in Tkinter on macOS 14 Sonoma.gh-111015: Ensure that IDLE.app and Python Launcher.app are installed with appropriate permissions on macOS builds.
gh-109286: Update macOS installer to use SQLite 3.43.1.
gh-71383: Update macOS installer to include an upstream Tcl/Tk fix for the
ttk::ThemeChanged
error encountered in Tkinter.gh-92603: Update macOS installer to include a fix accepted by upstream Tcl/Tk for a crash encountered after the first
tkinter.Tk()
instance is destroyed.
IDLE¶
bpo-35668: Add docstrings to the IDLE debugger module. Fix two bugs: initialize Idb.botframe (should be in Bdb); in Idb.in_rpc_code, check whether prev_frame is None before trying to use it. Greatly expand test_debugger.
C API¶
gh-106560: Fix redundant declarations in the public C API. Declare PyBool_Type and PyLong_Type only once. Patch by Victor Stinner.
gh-112438: Fix support of format units "es", "et", "es#", and "et#" in nested tuples in
PyArg_ParseTuple()
-like functions.gh-109521:
PyImport_GetImporter()
now sets RuntimeError if it fails to getsys.path_hooks
orsys.path_importer_cache
or they are not list and dict correspondingly. Previously it could return NULL without setting error in obscure cases, crash or raise SystemError if these attributes have wrong type.
Python 3.12.0 final¶
Release date: 2023-10-02
Core and Builtins¶
gh-109823: Fix bug where compiler does not adjust labels when removing an empty basic block which is a jump target.
gh-109719: Fix missing jump target labels when compiler reorders cold/warm blocks.
gh-109627: Fix bug where the compiler does not assign a new jump target label to a duplicated small exit block.
Library¶
Documentation¶
gh-109209: The minimum Sphinx version required for the documentation is now 4.2.
Windows¶
gh-109991: Update Windows build to use OpenSSL 3.0.11.
macOS¶
gh-109991: Update macOS installer to use OpenSSL 3.0.11.
Tools/Demos¶
gh-109991: Update GitHub CI workflows to use OpenSSL 3.0.11 and multissltests to use 1.1.1w, 3.0.11, and 3.1.3.
Python 3.12.0 release candidate 3¶
Release date: 2023-09-18
Core and Builtins¶
gh-109496: On a Python built in debug mode,
Py_DECREF()
now calls_Py_NegativeRefcount()
if the object is a dangling pointer to deallocated memory: memory filled with0xDD
"dead byte" by the debug hook on memory allocators. The fix is to check the reference count before checking for_Py_IsImmortal()
. Patch by Victor Stinner.gh-109371: Deopted instructions correctly for tool initialization and modified the incorrect assertion in instrumentation, when a previous tool already sets INSTRUCTION events
gh-105658: Fix bug where the line trace of an except block ending with a conditional includes an excess event with the line of the conditional expression.
gh-109219: Fix compiling type param scopes that use a name which is also free in an inner scope.
gh-109341: Fix crash when compiling an invalid AST involving a
ast.TypeAlias
.gh-109195: Fix source location for the
LOAD_*
instruction preceding aLOAD_SUPER_ATTR
to load thesuper
global (or shadowing variable) so that it encompasses only the namesuper
and not the following parentheses.gh-109118: Disallow nested scopes (lambdas, generator expressions, and comprehensions) within PEP 695 annotation scopes that are nested within classes.
gh-109114: Relax the detection of the error message for invalid lambdas inside f-strings to not search for arbitrary replacement fields to avoid false positives. Patch by Pablo Galindo
gh-109118: Fix interpreter crash when a NameError is raised inside the type parameters of a generic class.
gh-108976: Fix crash that occurs after de-instrumenting a code object in a monitoring callback.
gh-108732: Make iteration variables of module- and class-scoped comprehensions visible to pdb and other tools that use
frame.f_locals
again.gh-108959: Fix caret placement for error locations for subscript and binary operations that involve non-semantic parentheses and spaces. Patch by Pablo Galindo
Library¶
gh-108682: Enum: require
names=()
ortype=...
to create an empty enum using the functional syntax.gh-108843: Fix an issue in
ast.unparse()
when unparsing f-strings containing many quote types.
Documentation¶
Tests¶
gh-109396: Fix
test_socket.test_hmac_sha1()
in FIPS mode. Use a longer key: FIPS mode requires at least of at least 112 bits. The previous key was only 32 bits. Patch by Victor Stinner.gh-104736: Fix test_gdb on Python built with LLVM clang 16 on Linux ppc64le (ex: Fedora 38). Search patterns in gdb "bt" command output to detect when gdb fails to retrieve the traceback. For example, skip a test if
Backtrace stopped: frame did not save the PC
is found. Patch by Victor Stinner.gh-109237: Fix
test_site.test_underpth_basic()
when the working directory contains at least one non-ASCII character: encode the._pth
file to UTF-8 and enable the UTF-8 Mode to use UTF-8 for the child process stdout. Patch by Victor Stinner.gh-109230: Fix
test_pyexpat.test_exception()
: it can now be run from a directory different than Python source code directory. Before, the test failed in this case. Skip the test if Modules/pyexpat.c source is not available. Skip also the test on Python implementations other than CPython. Patch by Victor Stinner.gh-109015: Fix test_asyncio, test_imaplib and test_socket tests on FreeBSD if the TCP blackhole is enabled (
sysctl net.inet.tcp.blackhole
). Skip the few tests which failed withETIMEDOUT
which such non standard configuration. Currently, the FreeBSD GCP image enables TCP and UDP blackhole (sysctl net.inet.tcp.blackhole=2
andsysctl net.inet.udp.blackhole=1
). Patch by Victor Stinner.gh-91960: Skip
test_gdb
if gdb is unable to retrieve Python frame objects: if a frame is<optimized out>
. When Python is built with "clang -Og", gdb can fail to retrive the frame parameter of_PyEval_EvalFrameDefault()
. In this case, tests likepy_bt()
are likely to fail. Without getting access to Python frames,python-gdb.py
is mostly clueless on retrieving the Python traceback. Moreover,test_gdb
is no longer skipped on macOS if Python is built with Clang. Patch by Victor Stinner.gh-108962: Skip
test_tempfile.test_flags()
ifchflags()
fails with "OSError: [Errno 45] Operation not supported" (ex: on FreeBSD 13). Patch by Victor Stinner.gh-108851: Fix
test_tomllib
recursion tests for WASI buildbots: reduce the recursion limit and compute the maximum nested array/dict depending on the current available recursion limit. Patch by Victor Stinner.gh-108851: Add
get_recursion_available()
andget_recursion_depth()
functions to thetest.support
module. Patch by Victor Stinner.gh-108834: Add
--fail-rerun option
option to regrtest: if a test failed when then passed when rerun in verbose mode, exit the process with exit code 2 (error), instead of exit code 0 (success). Patch by Victor Stinner.gh-108834: Rename regrtest
--verbose2
option (-w
) to--rerun
. Keep--verbose2
as a deprecated alias. Patch by Victor Stinner.gh-108834: When regrtest reruns failed tests in verbose mode (
./python -m test --rerun
), tests are now rerun in fresh worker processes rather than being executed in the main process. If a test does crash or is killed by a timeout, the main process can detect and handle the killed worker process. Tests are rerun in parallel if the-jN
option is used to run tests in parallel. Patch by Victor Stinner.gh-103186: Suppress and assert expected RuntimeWarnings in test_sys_settrace.py
Build¶
gh-108740: Fix a race condition in
make regen-all
. Thedeepfreeze.c
source and files generated by Argument Clinic are now generated or updated before generating "global objects". Previously, some identifiers may miss depending on the order in which these files were generated. Patch by Victor Stinner.
Python 3.12.0 release candidate 2¶
Release date: 2023-09-05
Security¶
gh-108310: Fixed an issue where instances of
ssl.SSLSocket
were vulnerable to a bypass of the TLS handshake and included protections (like certificate verification) and treating sent unencrypted data as if it were post-handshake TLS encrypted data. Security issue reported as CVE 2023-40217 by Aapo Oksman. Patch by Gregory P. Smith.gh-107774: PEP 669 specifies that
sys.monitoring.register_callback
will generate an audit event. Pre-releases of Python 3.12 did not generate the audit event. This is now fixed.
Core and Builtins¶
gh-108520: Fix
multiprocessing.synchronize.SemLock.__setstate__()
to properly initializemultiprocessing.synchronize.SemLock._is_fork_ctx
. This fixes a regression when passing a SemLock accross nested processes.Rename
multiprocessing.synchronize.SemLock.is_fork_ctx
tomultiprocessing.synchronize.SemLock._is_fork_ctx
to avoid exposing it as public API.gh-108654: Restore locals shadowed by an inlined comprehension if the comprehension raises an exception.
gh-108487: Change an assert that would cause a spurious crash in a devious case that should only trigger deoptimization.
gh-106176: Use a
WeakValueDictionary
to track the lists containing the modules each thread is currently importing. This helps avoid a reference leak from keeping the list around longer than necessary. Weakrefs are used as GC can't interrupt the cleanup.gh-107901: Fix missing line number on
JUMP_BACKWARD
at the end of a for loop.gh-108390: Raise an exception when setting a non-local event (
RAISE
,EXCEPTION_HANDLED
, etc.) insys.monitoring.set_local_events
.Fixes crash when tracing in recursive calls to Python classes.
gh-91051: Fix abort / segfault when using all eight type watcher slots, on platforms where
char
is signed by default.gh-107724: In pre-release versions of 3.12, up to rc1, the sys.monitoring callback function for the
PY_THROW
event was missing the third, exception argument. That is now fixed.gh-107080: Trace refs builds (
--with-trace-refs
) were crashing when used with isolated subinterpreters. The problematic global state has been isolated to each interpreter. Other fixing the crashes, this change does not affect users.gh-77377: Ensure that multiprocessing synchronization objects created in a fork context are not sent to a different process created in a spawn context. This changes a segfault into an actionable RuntimeError in the parent process.
Library¶
gh-108469:
ast.unparse()
now supports new f-string syntax introduced in Python 3.12. Note that the f-string quotes are reselected for simplicity under the new syntax. (Patch by Steven Sun)gh-108682: Enum: raise
TypeError
ifsuper().__new__()
is called from a custom__new__
.gh-108295: Fix crashes related to use of weakrefs on
typing.TypeVar
.gh-64662: Fix support for virtual tables in
sqlite3.Connection.iterdump()
. Patch by Aviv Palivoda.gh-108111: Fix a regression introduced in gh-101251 for 3.12, resulting in an incorrect offset calculation in
gzip.GzipFile.seek()
.gh-105736: Harmonized the pure Python version of
OrderedDict
with the C version. Now, both versions set up their internal state in__new__
. Formerly, the pure Python version did the set up in__init__
.gh-108083: Fix bugs in the constructor of
sqlite3.Connection
andsqlite3.Connection.close()
where exceptions could be leaked. Patch by Erlend E. Aasland.gh-107963: Fix
multiprocessing.set_forkserver_preload()
to check the given list of modules names. Patch by Donghee Na.gh-106242: Fixes
os.path.normpath()
to handle embedded null characters without truncating the path.gh-107913: Fix possible losses of
errno
andwinerror
values inOSError
exceptions if they were cleared or modified by the cleanup code before creating the exception object.gh-107845:
tarfile.data_filter()
now takes the location of symlinks into account when determining their target, so it will no longer reject some valid tarballs withLinkOutsideDestinationError
.gh-107805: Fix signatures of module-level generated functions in
turtle
.gh-107715: Fix
doctest.DocTestFinder.find()
in presence of class names with special characters. Patch by Gertjan van Zwieten.gh-100814: Passing a callable object as an option value to a Tkinter image now raises the expected TclError instead of an AttributeError.
gh-106684: Close
asyncio.StreamWriter
when it is not closed by application leading to memory leaks. Patch by Kumar Aditya.gh-107396: tarfiles; Fixed use before assignment of self.exception for gzip decompression
gh-106052:
re
module: fix the matching of possessive quantifiers in the case of a subpattern containing backtracking.gh-100061: Fix a bug that causes wrong matches for regular expressions with possessive qualifier.
gh-99203: Restore following CPython <= 3.10.5 behavior of
shutil.make_archive()
: do not create an empty archive ifroot_dir
is not a directory, and, in that case, raiseFileNotFoundError
orNotADirectoryError
regardless offormat
choice. Beyond the brought-back behavior, the function may now also raise these exceptions indry_run
mode.
Documentation¶
gh-105052: Update
timeit
doc to specify that time in seconds is just the default.
Tests¶
gh-89392: Removed support of
test_main()
function in tests. They now always use normal unittest test runner.gh-108388: Convert test_concurrent_futures to a package of 7 sub-tests. Patch by Victor Stinner.
gh-108388: Split test_multiprocessing_fork, test_multiprocessing_forkserver and test_multiprocessing_spawn into test packages. Each package is made of 4 sub-tests: processes, threads, manager and misc. It allows running more tests in parallel and so reduce the total test duration. Patch by Victor Stinner.
gh-105776: Fix test_cppext when the C compiler command
-std=c11
option: remove-std=
options from the compiler command. Patch by Victor Stinner.gh-107178: Add the C API test for functions in the Mapping Protocol, the Sequence Protocol and some functions in the Object Protocol.
Build¶
Windows¶
gh-107565: Update Windows build to use OpenSSL 3.0.10.
gh-106242: Fixes
realpath()
to behave consistently when passed a path containing an embedded null character on Windows. In strict mode, it now raisesOSError
instead of the unexpectedValueError
, and in non-strict mode will make the path absolute.gh-106844: Fix integer overflow and truncating by the null character in
_winapi.LCMapStringEx()
which affectsntpath.normcase()
.
macOS¶
gh-107565: Update macOS installer to use OpenSSL 3.0.10.
Tools/Demos¶
C API¶
gh-107916: C API functions
PyErr_SetFromErrnoWithFilename()
,PyErr_SetExcFromWindowsErrWithFilename()
andPyErr_SetFromWindowsErrWithFilename()
save now the error code before callingPyUnicode_DecodeFSDefault()
.gh-107915: Such C API functions as
PyErr_SetString()
,PyErr_Format()
,PyErr_SetFromErrnoWithFilename()
and many others no longer crash or ignore errors if it failed to format the error message or decode the filename. Instead, they keep a corresponding error.gh-107810: Improve
DeprecationWarning
for uses ofPyType_Spec
with metaclasses that have customtp_new
.
Python 3.12.0 release candidate 1¶
Release date: 2023-08-05
Security¶
gh-102988: Reverted the
email.utils
security improvement change released in 3.12beta4 that unintentionally causedemail.utils.getaddresses
to fail to parse email addresses with a comma in the quoted name field. See gh-106669.gh-102509: Start initializing
ob_digit
during creation ofPyLongObject
objects. Patch by Illia Volochii.
Core and Builtins¶
gh-107263: Increase C recursion limit for functions other than the main interpreter from 800 to 1500. This should allow functions like
list.__repr__
andjson.dumps
to handle all the inputs that they could prior to 3.12gh-104432: Fix potential unaligned memory access on C APIs involving returned sequences of
char *
pointers within thegrp
andsocket
modules. These were revealed using a-fsaniziter=alignment
build on ARM macOS. Patch by Christopher Chavez.gh-106898: Add the exception as the third argument to
PY_UNIND
callbacks insys.monitoring
. This makes thePY_UNWIND
callback consistent with the other exception hanlding callbacks.gh-106895: Raise a
ValueError
when a monitoring callback funtion returnsDISABLE
for events that cannot be disabled locally.gh-106897: Add a
RERAISE
event tosys.monitoring
, which occurs when an exception is reraised, either explicitly by a plainraise
statement, or implicitly in anexcept
orfinally
block.gh-104621: Unsupported modules now always fail to be imported.
gh-106917: Fix classmethod-style
super()
method calls (i.e., where the second argument tosuper()
, or the implied second argument drawn fromself/cls
in the case of zero-arg super, is a type) when the target of the call is not a classmethod.gh-105699: Python no longer crashes due an infrequent race when initialzing per-interpreter interned strings. The crash would manifest when the interpreter was finalized.
gh-105699: Python no longer crashes due to an infrequent race in setting
Py_FileSystemDefaultEncoding
andPy_FileSystemDefaultEncodeErrors
(both deprecated), when simultaneously initializing two isolated subinterpreters. Now they are only set during runtime initialization.gh-106092: Fix a segmentation fault caused by a use-after-free bug in
frame_dealloc
when the trashcan delays the deallocation of aPyFrameObject
.gh-106719: No longer suppress arbitrary errors in the
__annotations__
getter and setter in the type and module types.gh-106723: Propagate
frozen_modules
to multiprocessing spawned process interpreters.gh-105235: Prevent out-of-bounds memory access during
mmap.find()
calls.
Library¶
gh-107077: Seems that in some conditions, OpenSSL will return
SSL_ERROR_SYSCALL
instead ofSSL_ERROR_SSL
when a certification verification has failed, but the error parameters will still containERR_LIB_SSL
andSSL_R_CERTIFICATE_VERIFY_FAILED
. We are now detecting this situation and raising the appropiatessl.SSLCertVerificationError
. Patch by Pablo Galindogh-107576: Fix
types.get_original_bases()
to only return__orig_bases__
if it is present oncls
directly. Patch by James Hilton-Balfe.gh-46376: Prevent memory leak and use-after-free when using pointers to pointers with ctypes
gh-62519: Make
gettext.pgettext()
search plural definitions when translation is not found.gh-83006: Document behavior of
shutil.disk_usage()
for non-mounted filesystems on Unix.gh-106186: Do not report
MultipartInvariantViolationDefect
defect when theemail.parser.Parser
class is used to parse emails withheadersonly=True
.gh-105002: Fix invalid result from
PurePath.relative_to()
method when attempting to walk a "..
" segment in other with walk_up enabled. AValueError
exception is now raised in this case.gh-106831: Fix potential missing
NULL
check ofd2i_SSL_SESSION
result in_ssl.c
.gh-106774: Update the bundled copy of pip to version 23.2.1.
gh-106752: Fixed several bugs in zipfile.Path, including: in
Path.match
, Windows separators are no longer honored (and never were meant to be); Fixedname
/suffix
/suffixes
/stem
operations when no filename is present and the Path is not at the root of the zipfile; Reworked glob for performance and more correct matching behavior.gh-106530: Revert a change to
colorsys.rgb_to_hls()
that caused division by zero for certain almost-white inputs. Patch by Terry Jan Reedy.gh-106403: Instances of
typing.TypeVar
,typing.ParamSpec
,typing.ParamSpecArgs
,typing.ParamSpecKwargs
, andtyping.TypeVarTuple
once again support weak references, fixing a regression introduced in Python 3.12.0 beta 1. Patch by Jelle Zijlstra.gh-106350: Detect possible memory allocation failure in the libtommath function
mp_init()
used by the_tkinter
module.gh-106263: Fix crash when calling
repr
with a manually constructed SignalDict object. Patch by Charlie Zhao.gh-105626: Change the default return value of
http.client.HTTPConnection.get_proxy_response_headers()
to beNone
and not{}
.bpo-18319: Ensure
gettext(msg)
retrieve translations even if a plural form exists. In other words:gettext(msg) == ngettext(msg, '', 1)
.
Documentation¶
gh-107305: Add documentation for
PyInterpreterConfig
andPy_NewInterpreterFromConfig()
. Also clarify some of the nearby docs relative to per-interpreter GIL.gh-107008: Document the
curses
module variablesLINES
andCOLS
.gh-106948: Add a number of standard external names to
nitpick_ignore
.gh-54738: Add documentation on how to localize the
argparse
module.
Tests¶
gh-107237:
test_logging
: Fixtest_udp_reconnection()
by increasing the timeout from 100 ms to 5 minutes (LONG_TIMEOUT). Patch by Victor Stinner.gh-106714: test_capi: Fix test_no_FatalError_infinite_loop() to no longer write a coredump, by using test.support.SuppressCrashReport. Patch by Victor Stinner.
gh-104090: Avoid creating a reference to the test object in
collectedDurations()
.gh-106752: Moved tests for
zipfile.Path
intoLib/test/test_zipfile/_path
. Madezipfile._path
a package.
Build¶
Windows¶
gh-99079: Update Windows build to use OpenSSL 3.0.9
macOS¶
gh-99079: Update macOS installer to use OpenSSL 3.0.9.
Tools/Demos¶
gh-106970: Fix bugs in the Argument Clinic
destination <name> clear
command; the destination buffers would never be cleared, and thedestination
directive parser would simply continue to the fault handler after processing the command. Patch by Erlend E. Aasland.gh-103186:
freeze
now fetchesCONFIG_ARGS
from the original CPython instance the Makefile uses to call utility scripts. Patch by Ijtaba Hussain.
C API¶
gh-107226:
PyModule_AddObjectRef()
is now only available in the limited API version 3.10 or later.
Python 3.12.0 beta 4¶
Release date: 2023-07-11
Security¶
gh-102988: CVE 2023-27043: Prevent
email.utils.parseaddr()
andemail.utils.getaddresses()
from returning the realname portion of an invalid RFC2822 email header in the email address portion of the 2-tuple returned after being parsed byemail._parseaddr.AddressList
.
Core and Builtins¶
gh-106396: When the format specification of an f-string expression is empty, the parser now generates an empty
ast.JoinedStr
node for it instead of an one-elementast.JoinedStr
with an empty stringast.Constant
.gh-106145: Make
end_lineno
andend_col_offset
required ontype_param
ast nodes.gh-105979: Fix crash in
_imp.get_frozen_object()
due to improper exception handling.gh-98931: Ensure custom
SyntaxError
error messages are raised for invalid imports with multiple targets. Patch by Pablo Galindogh-105908: Fixed bug where gh-99111 breaks future import
barry_as_FLUFL
in the Python REPL.gh-105340: Include the comprehension iteration variable in
locals()
inside a module- or class-scope comprehension.gh-105486: Change the repr of
ParamSpec
list of args intypes.GenericAlias
.
Library¶
gh-106524: Fix crash in
_sre.template()
with templates containing invalid group indices.gh-106510: Improve debug output for atomic groups in regular expressions.
gh-106503: Fix ref cycle in
asyncio._SelectorSocketTransport
by removing_write_ready
inclose
.gh-105497: Fix flag mask inversion when unnamed flags exist.
gh-90876: Prevent
multiprocessing.spawn
from failing to import in environments wheresys.executable
isNone
. This regressed in 3.11 with the addition of support for path-like objects in multiprocessing.gh-106292: Check for an instance-dict cached value in the
__get__()
method offunctools.cached_property()
. This better matches the pre-3.12 behavior and improves compatibility for users subclassingfunctools.cached_property()
and adding a__set__()
method.gh-106330: Fix incorrect matching of empty paths in
pathlib.PurePath.match()
. This bug was introduced in Python 3.12.0 beta 1.gh-102541: Make pydoc.doc catch bad module ImportError when output stream is not None.
gh-106152: Added PY_THROW event hook for
cProfile
for generatorsgh-106075: Added
asyncio.taskgroups.__all__
toasyncio.__all__
for export in star imports.gh-105987: Fix crash due to improper reference counting in
asyncio
eager task factory internal routines.gh-105974: Fix bug where a
typing.Protocol
class that had one or more non-callable members would raiseTypeError
whenissubclass()
was called against it, even if it defined a custom__subclasshook__
method. The behaviour in Python 3.11 and lower -- which has now been restored -- was not to raiseTypeError
in these situations if a custom__subclasshook__
method was defined. Patch by Alex Waygood.gh-96145: Reverted addition of
json.AttrDict
.gh-105497: Fix flag inversion when alias/mask members exist.
gh-104554: Add RTSPS scheme support in urllib.parse
gh-94777: Fix hanging
multiprocessing
ProcessPoolExecutor
when a child process crashes while data is being written in the call queue.
Documentation¶
gh-106232: Make timeit doc command lines compatible with Windows by using double quotes for arguments. This works on linux and macOS also.
Tests¶
gh-101634: When running the Python test suite with
-jN
option, if a worker stdout cannot be decoded from the locale encoding report a failed testn so the exitcode is non-zero. Patch by Victor Stinner.
Build¶
gh-106118: Fix compilation for platforms without
O_CLOEXEC
. The issue was introduced with Python 3.12b1 in gh-103295. Patch by Erlend Aasland.gh-104692: Include
commoninstall
as a prerequisite forbininstall
This ensures that
commoninstall
is completed beforebininstall
is started when parallel builds are used (make -j install
), and so thepython3
symlink is only installed after all standard library modules are installed.
Tools/Demos¶
gh-106359: Argument Clinic now explicitly forbids "kwarg splats" in function calls used as annotations.
C API¶
gh-105227: The new
PyType_GetDict()
provides the dictionary for the given type object that is normally exposed bycls.__dict__
. Normally it's sufficient to usetp_dict
, but for the static builtin typestp_dict
is now alwaysNULL
.PyType_GetDict()
provides the correct dict object instead.
Python 3.12.0 beta 3¶
Release date: 2023-06-19
Core and Builtins¶
gh-105840: Fix possible crashes when specializing function calls with too many
__defaults__
.gh-105831: Fix an f-string bug, where using a debug expression (the
=
sign) that appears in the last line of a file results to the debug buffer that holds the expression text being one character too small.gh-105800: Correctly issue
SyntaxWarning
in f-strings if invalid sequences are used. Patch by Pablo Galindogh-105587: The runtime can't guarantee that immortal objects will not be mutated by Extensions. Thus, this modifies _PyStaticObject_CheckRefcnt to warn instead of asserting.
gh-105564: Don't include artificil newlines in the
line
attribute of tokens in the APIs of thetokenize
module. Patch by Pablo Galindogh-105549: Tokenize separately
NUMBER
andNAME
tokens that are not ambiguous. Patch by Pablo Galindo.gh-105588: Fix an issue that could result in crashes when compiling malformed
ast
nodes.gh-105375: Fix bugs in the
builtins
module where exceptions could end up being overwritten.gh-105375: Fix bug in the compiler where an exception could end up being overwritten.
gh-105375: Improve error handling in
PyUnicode_BuildEncodingMap()
where an exception could end up being overwritten.gh-105435: Fix spurious newline character if file ends on a comment without a newline. Patch by Pablo Galindo
gh-105390: Correctly raise
tokenize.TokenError
exceptions instead ofSyntaxError
for tokenize errors such as incomplete input. Patch by Pablo Galindogh-104812: The "pending call" machinery now works for all interpreters, not just the main interpreter, and runs in all threads, not just the main thread. Some calls are still only done in the main thread, ergo in the main interpreter. This change does not affect signal handling nor the existing public C-API (
Py_AddPendingCall()
), which both still only target the main thread. The new functionality is meant strictly for internal use for now, since consequences of its use are not well understood yet outside some very restricted cases. This change brings the capability in line with the intention when the state was made per-interpreter several years ago.
Library¶
gh-105808: Fix a regression introduced in gh-101251 for 3.12, causing
gzip.GzipFile.flush()
to not flush the compressor (nor pass along thezip_mode
argument).gh-104799: Enable
ast.unparse()
to unparse function and class definitions created without the newtype_params
field from PEP 695. Patch by Jelle Zijlstra.gh-105745: Fix
webbrowser.Konqueror.open
method.gh-105375: Fix a bug in
_Unpickler_SetInputStream()
where an exception could end up being overwritten in case of failure.gh-105375: Fix bugs in
sys
where exceptions could end up being overwritten because of deferred error handling.gh-105605: Harden
pyexpat
error handling during module initialisation to prevent exceptions from possibly being overwritten, and objects from being dereferenced twice.gh-105375: Fix bug in
decimal
where an exception could end up being overwritten.gh-105375: Fix bugs in
_datetime
where exceptions could be overwritten in case of module initialisation failure.gh-105375: Fix bugs in
_ssl
initialisation which could lead to leaked references and overwritten exceptions.gh-105375: Fix a bug in
array.array
where an exception could end up being overwritten.gh-105375: Fix bugs in
_ctypes
where exceptions could end up being overwritten.gh-105375: Fix a bug in the
posix
module where an exception could be overwritten.gh-105375: Fix bugs in
_elementtree
where exceptions could be overwritten.gh-105375: Fix bugs in
zoneinfo
where exceptions could be overwritten.gh-105375: Fix bugs in
errno
where exceptions could be overwritten.gh-105375: Fix bugs in
pickle
where exceptions could be overwritten.gh-105375: Fix a bug in
sqlite3
where an exception could be overwritten in thecollation
callback.gh-105332: Revert pickling method from by-name back to by-value.
gh-104310: In the beta 1 release we added a utility function for extension module authors, to use when testing their module for support in multiple interpreters or under a per-interpreter GIL. The name of that function has changed from
allowing_all_extensions
to_incompatible_extension_module_restrictions
. The default for the "disable_check" argument has change fromTrue
toFalse
, to better match the new function name.gh-104996: Improve performance of
pathlib.PurePath
initialisation by deferring joining of paths when multiple arguments are given.gh-102541: Hide traceback in
help()
prompt, when import failed.
Tests¶
gh-105084: When the Python build is configured
--with-wheel-pkg-dir
, tests requiring thesetuptools
andwheel
wheels will search for the wheels inWHEEL_PKG_DIR
.
Windows¶
gh-105436: Ensure that an empty environment block is terminated by two null characters, as is required by Windows.
C API¶
gh-105375: Fix a bug in
PyErr_WarnExplicit()
where an exception could end up being overwritten if the API failed internally.gh-105603: We've renamed the new (in 3.12)
PyInterpreterConfig.own_gil
toPyInterpreterConfig.gil
and changed the meaning of the value from "bool" to an integer with supported values ofPyInterpreterConfig_DEFAULT_GIL
,PyInterpreterConfig_SHARED_GIL
, andPyInterpreterConfig_OWN_GIL
. The default is "shared".gh-105387: In the limited C API version 3.12,
Py_INCREF()
andPy_DECREF()
functions are now implemented as opaque function calls to hide implementation details. Patch by Victor Stinner.gh-103968:
PyType_FromMetaclass()
now allows metaclasses withtp_new
set toNULL
.
Python 3.12.0 beta 2¶
Release date: 2023-06-06
Security¶
Core and Builtins¶
gh-105259: Don't include newline character for trailing
NEWLINE
tokens emitted in thetokenize
module. Patch by Pablo Galindogh-105324: Fix the main function of the
tokenize
module when reading fromsys.stdin
. Patch by Pablo Galindogh-98963: Restore the ability for a subclass of
property
to define__slots__
or otherwise be dict-less by ignoring failures to set a docstring on such a class. This behavior had regressed in 3.12beta1. AnAttributeError
where there had not previously been one was disruptive to existing code.gh-105194: Do not escape with backslashes f-string format specifiers. Patch by Pablo Galindo
gh-105162: Fixed bug in generator.close()/throw() where an inner iterator would be ignored when the outer iterator was instrumented.
gh-105164: Ensure annotations are set up correctly if the only annotation in a block is within a
match
block. Patch by Jelle Zijlstra.gh-104799: Attributes of
ast
nodes that are lists now default to the empty list if omitted. This means that some code that previously raisedTypeError
when the AST node was used will now proceed with the empty list instead. Patch by Jelle Zijlstra.gh-105035: Fix
super()
calls on types with customtp_getattro
implementation (e.g. meta-types.)gh-105017: Show CRLF lines in the tokenize string attribute in both NL and NEWLINE tokens. Patch by Marta Gómez.
gh-105013: Fix handling of multiline parenthesized lambdas in
inspect.getsource()
. Patch by Pablo Galindogh-105017: Do not include an additional final
NL
token when parsing files having CRLF lines. Patch by Marta Gómez.gh-104976: Ensure that trailing
DEDENT
tokenize.TokenInfo
objects emitted by thetokenize
module are reported as in Python 3.11. Patch by Pablo Galindogh-104972: Ensure that the
line
attribute intokenize.TokenInfo
objects in thetokenize
module are always correct. Patch by Pablo Galindogh-104955: Fix signature for the new
__release_buffer__()
slot. Patch by Jelle Zijlstra.gh-104690: Starting new threads and process creation through
os.fork()
during interpreter shutdown (such as fromatexit
handlers) is no longer supported. It can lead to race condition between the main Python runtime thread freeing thread states while internalthreading
routines are trying to allocate and use the state of just created threads. Or forked children trying to use the mid-shutdown runtime and thread state in the child process.gh-104879: Fix crash when accessing the
__module__
attribute of type aliases defined outside a module. Patch by Jelle Zijlstra.gh-104825: Tokens emitted by the
tokenize
module do not include an implicit\n
character in theline
attribute anymore. Patch by Pablo Galindo
Library¶
gh-105280: Fix bug where
isinstance([], collections.abc.Mapping)
could evaluate toTrue
if garbage collection happened at the wrong time. The bug was caused by changes to the implementation oftyping.Protocol
in Python 3.12.gh-105239: Fix longstanding bug where
issubclass(object, typing.Protocol)
would evaluate toTrue
in some edge cases. Patch by Alex Waygood.gh-105080: Fixed inconsistent signature on derived classes for
inspect.signature()
gh-105144: Fix a recent regression in the
typing
module. The regression meant that doingclass Foo(X, typing.Protocol)
, whereX
was a class that hadabc.ABCMeta
as its metaclass, would then cause subsequentisinstance(1, X)
calls to erroneously raiseTypeError
. Patch by Alex Waygood.gh-105113: Improve performance of
pathlib.PurePath.match()
by compiling anre.Pattern
object for the entire pattern.gh-101588: Deprecate undocumented copy/deepcopy/pickle support for itertools.
gh-103631: Fix
pathlib.PurePosixPath(pathlib.PureWindowsPath(...))
not converting path separators to restore 3.11 compatible behavior.gh-104947: Make comparisons between
pathlib.PureWindowsPath
objects consistent across Windows and Posix to match 3.11 behavior.gh-104935: Fix bugs with the interaction between
typing.runtime_checkable()
andtyping.Generic
that were introduced by the PEP 695 implementation. Patch by Jelle Zijlstra.gh-104874: Document the
__name__
and__supertype__
attributes oftyping.NewType
. Patch by Jelle Zijlstra.gh-104799: Adjust the location of the (see PEP 695)
type_params
field onast.ClassDef
,ast.AsyncFunctionDef
, andast.FunctionDef
to better preserve backward compatibility. Patch by Jelle Zijlstragh-104797: Allow
typing.Protocol
classes to inherit fromcollections.abc.Buffer
. Patch by Jelle Zijlstra.gh-104372: On Linux where
subprocess
can use thevfork()
syscall for faster spawning, prevent the parent process from blocking other threads by dropping the GIL while it waits for the vfork'ed child processexec()
outcome. This prevents spawning a binary from a slow filesystem from blocking the rest of the application.gh-99108: We now release the GIL around built-in
hashlib
computations of reasonable size for the SHA families and MD5 hash functions, matching what our OpenSSL backed hash computations already does.gh-104399: Prepare the
_tkinter
module for building with Tcl 9.0 and future libtommath by replacing usage of deprecated functionsmp_to_unsigned_bin_n()
andmp_unsigned_bin_size()
when necessary.gh-102024: Reduce calls of
_idle_semaphore.release()
inconcurrent.futures.thread._worker()
.
Documentation¶
gh-89455: Add missing documentation for the
max_group_depth
andmax_group_width
parameters and theexceptions
attribute of thetraceback.TracebackException
class.gh-89412: Add missing documentation for the
end_lineno
andend_offset
attributes of thetraceback.TracebackException
class.gh-104943: Remove mentions of old Python versions in
typing.NamedTuple
.
Build¶
Windows¶
gh-105146: Updated the links at the end of the installer to point to Discourse rather than the mailing lists.
gh-103646: When installed from the Microsoft Store,
pip
no longer defaults to per-user installs. However, as the install directory is unwritable, it should automatically decide to do a per-user install anyway. This should resolve issues whenpip
is passed an option that conflicts with--user
.gh-88745: Improve performance of
shutil.copy2()
by using the operating system'sCopyFile2
function. This may result in subtle changes to metadata copied along with some files, bringing them in line with normal OS behavior.gh-104820: Fixes
stat()
and related functions on file systems that do not support file ID requests. This includes FAT32 and exFAT.gh-104803: Add
os.path.isdevdrive()
to detect whether a path is on a Windows Dev Drive. ReturnsFalse
on platforms that do not support Dev Drive, and is absent on non-Windows platforms.
macOS¶
gh-103142: Update macOS installer to use OpenSSL 1.1.1u.
IDLE¶
gh-104719: Remove IDLE's modification of tokenize.tabsize and test other uses of tokenize data and methods.
C API¶
gh-105115:
PyTypeObject.tp_bases
(andtp_mro
) for builtin static types are now shared by all interpreters, whereas in 3.12-beta1 they were stored onPyInterpreterState
. Also note that now the tuples are immortal objects.gh-105071: Add
PyUnstable_Exc_PrepReraiseStar
to the unstable C api to expose the implementation ofexcept*
.gh-104668: Don't call
PyOS_InputHook
orPyOS_ReadlineFunctionPointer
in subinterpreters, since it's generally difficult to avoid using global state in their registered callbacks. This also avoids situations where extensions may find themselves running in a subinterpreter they don't support (or haven't yet been loaded in).
Python 3.12.0 beta 1¶
Release date: 2023-05-22
Security¶
gh-99889: Fixed a security in flaw in
uu.decode()
that could allow for directory traversal based on the input if noout_file
was specified.gh-104049: Do not expose the local on-disk location in directory indexes produced by
http.client.SimpleHTTPRequestHandler
.gh-99108: Upgrade built-in
hashlib
SHA3 implementation to a verified implementation from theHACL*
project. Used when OpenSSL is not present or lacks SHA3.gh-102153:
urllib.parse.urlsplit()
now strips leading C0 control and space characters following the specification for URLs defined by WHATWG in response to CVE 2023-24329. Patch by Illia Volochii.
Core and Builtins¶
gh-102856: Implement PEP 701 changes in the
tokenize
module. Patch by Marta Gómez Macías and Pablo Galindo Salgadogh-104615: Fix wrong ordering of assignments in code like
a, a = x, y
. Contributed by Carl Meyer.gh-104572: Improve syntax error message for invalid constructs in PEP 695 contexts and in annotations when
from __future__ import annotations
is active.gh-104482: Fix three error handling bugs in ast.c's validation of pattern matching statements.
gh-102818: Do not add a frame to the traceback in the
sys.setprofile
andsys.settrace
trampoline functions. This ensures that frames are not duplicated if an exception is raised in the callback function, and ensures that frames are not omitted if a C callback is used and that does not add the frame.gh-104405: Fix an issue where some bytecode instructions could ignore PEP 523 when "inlining" calls.
gh-103082: Change behavior of
sys.monitoring.events.LINE
events insys.monitoring
: Line events now occur when a new line is reached dynamically, instead of using a static approximation, as before. This makes the behavior very similar to that of "line" events insys.settrace
. This should ease porting of tools from 3.11 to 3.12.gh-104263: Fix
float("nan")
to produce a quiet NaN on platforms (like MIPS) where the meaning of the signalling / quiet bit is inverted from its usual meaning. Also introduce a new macroPy_INFINITY
matching C99'sINFINITY
, and refactor internals to rely on C99'sNAN
andINFINITY
macros instead of hard-coding bit patterns for infinities and NaNs. Thanks Sebastian Berg.gh-99113: Multi-phase init extension modules may now indicate that they support running in subinterpreters that have their own GIL. This is done by using
Py_MOD_PER_INTERPRETER_GIL_SUPPORTED
as the value for thePy_mod_multiple_interpreters
module def slot. Otherwise the module, by default, cannot be imported in such subinterpreters. (This does not affect the main interpreter or subinterpreters that do not have their own GIL.) In addition to the isolation that multi-phase init already normally requires, support for per-interpreter GIL involves one additional constraint: thread-safety. If the module has external (linked) dependencies and those libraries have any state that isn't thread-safe then the module must do the additional work to add thread-safety. This should be an uncommon case.gh-99113: The GIL is now (optionally) per-interpreter. This is the fundamental change for PEP 684. This is all made possible by virtue of the isolated state of each interpreter in the process. The behavior of the main interpreter remains unchanged. Likewise, interpreters created using
Py_NewInterpreter()
are not affected. To get an interpreter with its own GIL, callPy_NewInterpreterFromConfig()
.gh-104108: Multi-phase init extension modules may now indicate whether or not they actually support multiple interpreters. By default such modules are expected to support use in multiple interpreters. In the uncommon case that one does not, it may use the new
Py_mod_multiple_interpreters
module def slot. A value of0
means the module does not support them.1
means it does. The default is1
.gh-104142: Fix an issue where
list
ortuple
repetition could fail to respect PEP 683.gh-104078: Improve the performance of
PyObject_HasAttrString()
gh-104066: Improve the performance of
hasattr()
for module objects with a missing attribute.gh-104028: Reduce object creation while calling callback function from gc. Patch by Donghee Na.
gh-104018: Disallow the "z" format specifier in %-format of bytes objects.
gh-102213: Fix performance loss when accessing an object's attributes with
__getattr__
defined.gh-103895: Improve handling of edge cases in showing
Exception.__notes__
. Ensures that the messages always end with a newline and that string/bytes are not exploded over multiple lines. Patch by Carey Metcalfe.gh-103907: Don't modify the refcounts of known immortal objects (
True
,False
, andNone
) in the main interpreter loop.gh-103899: Provide a helpful hint in the
TypeError
message when accidentally calling a module object that has a callable attribute of the same name (such asdis.dis()
ordatetime.datetime
).gh-103845: Remove both line and instruction instrumentation before adding new ones for monitoring, to avoid newly added instrumentation being removed immediately.
gh-103763: Implement PEP 695, adding syntactic support for generic classes, generic functions, and type aliases.
A new
type X = ...
syntax is added for type aliases, which resolves at runtime to an instance of the new classtyping.TypeAliasType
. The value is lazily evaluated and is accessible through the.__value__
attribute. This is implemented as a new AST nodeast.TypeAlias
.New syntax (
class X[T]: ...
,def func[T](): ...
) is added for defining generic functions and classes. This is implemented as a newtype_params
attribute on the AST nodes for classes and functions. This node holds instances of the new AST classesast.TypeVar
,ast.ParamSpec
, andast.TypeVarTuple
.typing.TypeVar
,typing.ParamSpec
,typing.ParamSpecArgs
,typing.ParamSpecKwargs
,typing.TypeVarTuple
, andtyping.Generic
are now implemented in C rather than Python.There are new bytecode instructions
LOAD_LOCALS
,LOAD_CLASSDICT_OR_GLOBAL
, andLOAD_CLASSDICT_OR_DEREF
to support correct resolution of names in class namespaces.Patch by Eric Traut, Larry Hastings, and Jelle Zijlstra.
gh-103801: Adds three minor linting fixes to the wasm module caught that were caught by ruff.
gh-103793: Optimized asyncio Task creation by deferring expensive string formatting (task name generation) from Task creation to the first time
get_name
is called. This makes asyncio benchmarks up to 5% faster.gh-102310: Change the error range for invalid bytes literals.
gh-103590: Do not wrap a single exception raised from a
try-except*
construct in anExceptionGroup
.gh-103650: Change the perf map format to remove the '0x' prefix from the addresses
gh-102856: Implement the required C tokenizer changes for PEP 701. Patch by Pablo Galindo Salgado, Lysandros Nikolaou, Batuhan Taskaya, Marta Gómez Macías and sunmy2019.
gh-100530: Clarify the error message raised when the called part of a class pattern isn't actually a class.
gh-101517: Fix bug in line numbers of instructions emitted for
except*
.gh-103492: Clarify
SyntaxWarning
with literalis
comparison by specifying which literal is problematic, since comparisons usingis
with e.g.None
and bool literals are idiomatic.gh-87729: Add
LOAD_SUPER_ATTR
(and a specialization forsuper().method()
) to speed upsuper().method()
andsuper().attr
. This makessuper().method()
roughly 2.3x faster and brings it within 20% of the performance of a simple method call. Patch by Vladimir Matveev and Carl Meyer.gh-103488: Change the internal offset distinguishing yield and return target addresses, so that the instruction pointer is correct for exception handling and other stack unwinding.
gh-82012: The bitwise inversion operator (
~
) on bool is deprecated. It returns the bitwise inversion of the underlyingint
representation such thatbool(~True) == True
, which can be confusing. Usenot
for logical negation of bools. In the rare case that you really need the bitwise inversion of the underlyingint
, convert to int explicitly~int(x)
.gh-77757: Exceptions raised in a typeobject's
__set_name__
method are no longer wrapped by aRuntimeError
. Context information is added to the exception as a PEP 678 note.gh-103333:
AttributeError
now retains thename
attribute when pickled and unpickled.gh-103242: Migrate
set_ecdh_curve()
method not to use deprecated OpenSSL APIs. Patch by Donghee Na.gh-103323: We've replaced our use of
_PyRuntime.tstate_current
with a thread-local variable. This is a fairly low-level implementation detail, and there should be no change in behavior.gh-84436: The implementation of PEP-683 which adds Immortal Objects by using a fixed reference count that skips reference counting to make objects truly immutable.
gh-102700: Allow built-in modules to be submodules. This allows submodules to be statically linked into a CPython binary.
gh-103082: Implement PEP 669 Low Impact Monitoring for CPython.
gh-88691: Reduce the number of inline
CACHE
entries forCALL
.gh-102500: Make the buffer protocol accessible in Python code using the new
__buffer__
and__release_buffer__
magic methods. See PEP 688 for details. Patch by Jelle Zijlstra.gh-97933: PEP 709: inline list, dict and set comprehensions to improve performance and reduce bytecode size.
gh-99184: Bypass instance attribute access of
__name__
inrepr
ofweakref.ref
.gh-98003: Complex function calls are now faster and consume no C stack space.
bpo-39610:
len()
for 0-dimensionalmemoryview
objects (such asmemoryview(ctypes.c_uint8(42))
) now raises aTypeError
. Previously this returned1
, which was not consistent withmem_0d[0]
raising anIndexError
.bpo-31821: Fix
pause_reading()
to work when called fromconnection_made()
inasyncio
.
Library¶
gh-104600:
functools.update_wrapper()
now sets the__type_params__
attribute (added by PEP 695).gh-104340: When an
asyncio
pipe protocol loses its connection due to an error, and the caller doesn't awaitwait_closed()
on the correspondingStreamWriter
, don't log a warning about an exception that was never retrieved. After all, according to theStreamWriter.close()
docs, thewait_closed()
call is optional ("not mandatory").gh-104555: Fix issue where an
issubclass()
check comparing a classX
against aruntime-checkable protocol
Y
with non-callable members would not causeTypeError
to be raised if anisinstance()
call had previously been made comparing an instance ofX
toY
. This issue was present in edge cases on Python 3.11, but became more prominent in 3.12 due to some unrelated changes that were made to runtime-checkable protocols. Patch by Alex Waygood.gh-104372: Refactored the
_posixsubprocess
internals to avoid Python C API usage between fork and exec when markingpass_fds=
file descriptors inheritable.gh-104484: Added case_sensitive argument to
pathlib.PurePath.match()
gh-75367: Fix data descriptor detection in
inspect.getattr_static()
.gh-104536: Fix a race condition in the internal
multiprocessing.process
cleanup logic that could manifest as an unintendedAttributeError
when callingprocess.close()
.gh-103857: Update datetime deprecations' stracktrace to point to the calling line
gh-101520: Move the core functionality of the
tracemalloc
module in thePython/
folder, leaving just the module wrapper inModules/
.gh-104392: Remove undocumented and unused
_paramspec_tvars
attribute from some classes intyping
.gh-102613: Fix issue where
pathlib.Path.glob()
raisedRecursionError
when walking deep directory trees.gh-103000: Improve performance of
dataclasses.asdict()
for the common case where dict_factory isdict
. Patch by David C Ellis.gh-104301: Allow leading whitespace in disambiguated statements in
pdb
.gh-104139: Teach
urllib.parse.unsplit()
to retain the"//"
when assemblingitms-services://?action=generate-bugs
style Apple Platform Deployment URLs.gh-104307:
socket.getnameinfo()
now releases the GIL while contacting the DNS servergh-104310: Users may now use
importlib.util.allowing_all_extensions()
(a context manager) to temporarily disable the strict compatibility checks for importing extension modules in subinterpreters.gh-87695: Fix issue where
pathlib.Path.glob()
raisedOSError
when it encountered a symlink to an overly long path.gh-104265: Prevent possible crash by disallowing instantiation of the
_csv.Reader
and_csv.Writer
types. The regression was introduced in 3.10.0a4 with PR 23224 (bpo-14935). Patch by Radislav Chugunov.gh-102613: Improve performance of
pathlib.Path.glob()
when expanding recursive wildcards ("**
") by merging adjacent wildcards and de-duplicating results only when necessary.gh-65772: Remove unneeded comments and code in turtle.py.
gh-90208: Fixed issue where
pathlib.Path.glob()
returned incomplete results when it encountered aPermissionError
. This method now suppresses allOSError
exceptions, except those raised from callingis_dir()
on the top-level path.gh-104144: Optimize
asyncio.TaskGroup
when usingasyncio.eager_task_factory()
. Skip scheduling a done callback if a TaskGroup task completes eagerly.gh-104144: Optimize
asyncio.gather()
when usingasyncio.eager_task_factory()
to complete eagerly if all fututres completed eagerly. Avoid scheduling done callbacks for futures that complete eagerly.gh-104114: Fix issue where
pathlib.Path.glob()
returns paths using the case of non-wildcard segments for corresponding path segments, rather than the real filesystem case.gh-104104: Improve performance of
pathlib.Path.glob()
by usingre.IGNORECASE
to implement case-insensitive matching.gh-104102: Improve performance of
pathlib.Path.glob()
when evaluating patterns that contain'../'
segments.gh-103822: Update the return type of
weekday
to the newly added Day attributegh-103629: Update the
repr
oftyping.Unpack
according to PEP 692.gh-103963: Make
dis
display the names of the args forCALL_INTRINSIC_*
.gh-104035: Do not ignore user-defined
__getstate__
and__setstate__
methods for slotted frozen dataclasses.gh-103987: In
mmap
, fix several bugs that could lead to access to memory-mapped files after they have been invalidated.gh-88773: Added
turtle.teleport()
to theturtle
module to move a turtle to a new point without tracing a line, visible or invisible. Patch by Liam Gersten.gh-103935: Use
io.open_code()
for files to be executed instead of rawopen()
gh-68968: Fixed garbled output of
assertEqual()
when an input lacks final newline.gh-100370: Fix potential
OverflowError
insqlite3.Connection.blobopen()
for 32-bit builds. Patch by Erlend E. Aasland.gh-102628: Substitute CTRL-D with CTRL-Z in
sqlite3
CLI banner when running on Windows.gh-103636: Module-level attributes
January
andFebruary
are deprecated fromcalendar
.gh-103583: Isolate
_multibytecodec
and codecs extension modules. Patches by Erlend E. Aasland.gh-103848: Add checks to ensure that
[
bracketed]
hosts found byurllib.parse.urlsplit()
are of IPv6 or IPvFuture format.gh-103872: Update the bundled copy of pip to version 23.1.2.
gh-74940: The C.UTF-8 locale is no longer converted to en_US.UTF-8, enabling the use of UTF-8 encoding on systems which have no locales installed.
gh-103861: Fix
zipfile.Zipfile
creating invalid zip files whenforce_zip64
was used to add files to them. Patch by Carey Metcalfe.gh-103857: Deprecated
datetime.datetime.utcnow()
anddatetime.datetime.utcfromtimestamp()
. (Patch by Paul Ganssle)gh-103839: Avoid compilation error due to tommath.h not being found when building Tkinter against Tcl 8.7 built with bundled libtommath.
gh-103791:
contextlib.suppress
now supports suppressing exceptions raised as part of anExceptionGroup
. If other exceptions exist on the group, they are re-raised in a group that does not contain the suppressed exceptions.gh-90750: Use
datetime.datetime.fromisocalendar()
in the implementation ofdatetime.datetime.strptime()
, which should now accept only valid ISO dates. (Patch by Paul Ganssle)gh-103685: Prepare
tkinter.Menu.index()
for Tk 8.7 so that it does not raiseTclError: expected integer but got ""
when it should returnNone
.gh-81403:
urllib.request.CacheFTPHandler
no longer raisesURLError
if a cached FTP instance is reused. ftplib's endtransfer method calls voidresp to drain the connection to handle FTP instance reuse properly.gh-103699: Add
__orig_bases__
to non-generic TypedDicts, call-based TypedDicts, and call-based NamedTuples. Other TypedDicts and NamedTuples already had the attribute.gh-92248: Deprecate
type
,choices
, andmetavar
parameters ofargparse.BooleanOptionalAction
.gh-89415: Add
socket
constants for source-specific multicast. Patch by Reese Hyde.gh-103673:
socketserver
gainsForkingUnixStreamServer
andForkingUnixDatagramServer
classes. Patch by Jay Berry.gh-103636: Added Enum for months and days in the calendar module.
gh-84976: Create a new
Lib/_pydatetime.py
file that defines the Python version of thedatetime
module, and makedatetime
import the contents of the new library only if the C implementation is missing. Currently, the full Python implementation is defined and then deleted if the C implementation is not available, slowing downimport datetime
unnecessarily.gh-103596: Attributes/methods are no longer shadowed by same-named enum members, although they may be shadowed by enum.property's.
gh-103584: Updated
importlib.metadata
with changes fromimportlib_metadata
5.2 through 6.5.0, including: Supportinstalled-files.txt
forDistribution.files
when present.PackageMetadata
now stipulates an additionalget
method allowing for easy querying of metadata keys that may not be present.packages_distributions
now honors packages and modules with Python modules that not.py
sources (e.g..pyc
,.so
). Expand protocol forPackageMetadata.get_all
to match the upstream implementation ofemail.message.Message.get_all
in python/typeshed#9620. Deprecated use ofDistribution
without defining abstract methods. Deprecated expectation thatPackageMetadata.__getitem__
will returnNone
for missing keys. In the future, it will raise aKeyError
.gh-103578: Fixed a bug where
pdb
crashes when reading source file with different encoding by replacingio.open()
withio.open_code()
. The new method would also call into the hook set byPyFile_SetOpenCodeHook()
.gh-103556: Now creating
inspect.Signature
objects with positional-only parameter with a default followed by a positional-or-keyword parameter without one is impossible.gh-103559: Update the bundled copy of pip to version 23.1.1.
gh-103548: Improve performance of
pathlib.Path.absolute()
andcwd()
by joining paths only when necessary. Also improve performance ofpathlib.PurePath.is_absolute()
on Posix by skipping path parsing and normalization.gh-103538: Remove
_tkinter
module code guarded by definition of theTK_AQUA
macro which was only needed for Tk 8.4.7 or earlier and was never actually defined by any build system or documented for manual use.gh-103525: Fix misleading exception message when mixed
str
andbytes
arguments are supplied topathlib.PurePath
andPath
.gh-103489: Add
getconfig()
andsetconfig()
toConnection
to make configuration changes to a database connection. Patch by Erlend E. Aasland.gh-103365: Set default Flag boundary to
STRICT
and fix bitwise operations.gh-103472: Avoid a potential
ResourceWarning
inhttp.client.HTTPConnection
by closing the proxy / tunnel's CONNECT response explicitly.gh-103462: Fixed an issue with using
writelines()
inasyncio
to send very large payloads that exceed the amount of data that can be written in one call tosocket.socket.send()
orsocket.socket.sendmsg()
, resulting in the remaining buffer being left unwritten.gh-103449: Fix a bug in doc string generation in
dataclasses.dataclass()
.gh-103092: Isolate
_collections
(apply PEP 687). Patch by Erlend E. Aasland.gh-103357: Added support for
logging.Formatter
defaults
parameter tologging.config.dictConfig()
andlogging.config.fileConfig()
. Patch by Bar Harel.gh-74690: The performance of
isinstance()
checks againstruntime-checkable protocols
has been considerably improved for protocols that only have a few members. To achieve this improvement, several internal implementation details of thetyping
module have been refactored, includingtyping._ProtocolMeta.__instancecheck__
,typing._is_callable_members_only
, andtyping._get_protocol_attrs
. Patches by Alex Waygood.gh-74690: The members of a runtime-checkable protocol are now considered "frozen" at runtime as soon as the class has been created. See "What's new in Python 3.12" for more details.
gh-103256: Fixed a bug that caused
hmac
to raise an exception when the requested hash algorithm was not available in OpenSSL despite being available separately as part ofhashlib
itself. It now falls back properly to the built-in. This could happen when, for example, your OpenSSL does not include SHA3 support and you want to computehmac.digest(b'K', b'M', 'sha3_256')
.gh-103285: Improve performance of
ast.get_source_segment()
.gh-103225: Fix a bug in
pdb
when displaying line numbers of module-level source code.gh-93910: Remove deprecation of enum
member.member
access.gh-102978: Fixes
unittest.mock.patch()
not enforcing function signatures for methods decorated with@classmethod
or@staticmethod
when patch is called withautospec=True
.gh-103092: Isolate
_socket
(apply PEP 687). Patch by Erlend E. Aasland.gh-100479: Add
pathlib.PurePath.with_segments()
, which creates a path object from arguments. This method is called whenever a derivative path is created, such as frompathlib.PurePath.parent
. Subclasses may override this method to share information between path objects.gh-103220: Fix issue where
os.path.join()
added a slash when joining onto an incomplete UNC drive with a trailing slash on Windows.gh-103204: Fixes
http.server
accepting HTTP requests with HTTP version numbers preceded by '+', or '-', or with digit-separating '_' characters. The length of the version numbers is also constrained.gh-75586: Fix various Windows-specific issues with
shutil.which
.gh-103193: Improve performance of
inspect.getattr_static()
. Patch by Alex Waygood.gh-103176:
sys._current_exceptions()
now returns a mapping from thread-id to an exception instance, rather than to a(typ, exc, tb)
tuple.gh-103015: Add entrypoint keyword-only parameter to
sqlite3.Connection.load_extension()
, for overriding the SQLite extension entry point. Patch by Erlend E. Aasland.gh-103000: Improve performance of
dataclasses.astuple()
anddataclasses.asdict()
in cases where the contents are common Python types.gh-102953: The extraction methods in
tarfile
, andshutil.unpack_archive()
, have a new a filter argument that allows limiting tar features than may be surprising or dangerous, such as creating files outside the destination directory. See Extraction filters for details.gh-97696: Implemented an eager task factory in asyncio. When used as a task factory on an event loop, it performs eager execution of coroutines. Coroutines that are able to complete synchronously (e.g. return or raise without blocking) are returned immediately as a finished task, and the task is never scheduled to the event loop. If the coroutine blocks, the (pending) task is scheduled and returned.
gh-81079: Add case_sensitive keyword-only argument to
pathlib.Path.glob()
andrglob()
.gh-101819: Isolate the
io
extension module by applying PEP 687. Patch by Kumar Aditya, Victor Stinner, and Erlend E. Aasland.gh-91896: Deprecate
collections.abc.ByteString
gh-101362: Speed up
pathlib.Path
construction by omitting the path anchor from the internal list of path parts.gh-102114: Functions in the
dis
module that accept a source code string as argument now print a more concise traceback when the string contains a syntax or indentation error.gh-62432: The
unittest
runner will now exit with status code 5 if no tests were run. It is common for test runner misconfiguration to fail to find any tests, this should be an error.gh-78079: Fix incorrect normalization of UNC device path roots, and partial UNC share path roots, in
pathlib.PurePath
. Pathlib no longer appends a trailing slash to such paths.gh-85984: Add
tty.cfmakeraw()
andtty.cfmakecbreak()
totty
and modernize, the behavior oftty.setraw()
andtty.setcbreak()
to use POSIX.1-2017 Chapter 11 "General Terminal Interface" flag masks by default.gh-101688: Implement
types.get_original_bases()
to provide further introspection for types.gh-101640:
argparse.ArgumentParser
now catches errors when writing messages, such as whensys.stderr
isNone
. Patch by Oleg Iarygin.gh-83861: Fix datetime.astimezone method return value when invoked on a naive datetime instance that represents local time falling in a timezone transition gap. PEP 495 requires that instances with fold=1 produce earlier times than those with fold=0 in this case.
gh-89550: Decrease execution time of some
gzip
file writes by 15% by adding more appropriate buffering.gh-95299: Remove the bundled setuptools wheel from
ensurepip
, and stop installing setuptools in environments created byvenv
.gh-99353: Respect the
http.client.HTTPConnection
.debuglevel
flag inurllib.request.AbstractHTTPHandler
when its constructor parameterdebuglevel
is not set. And do the same for*HTTPS*
.gh-98040: Remove the long-deprecated
imp
module.gh-97850: Deprecate
pkgutil.find_loader()
andpkgutil.get_loader()
in favor ofimportlib.util.find_spec()
.gh-94473: Flatten arguments in
tkinter.Canvas.coords()
. It now accepts not onlyx1, y1, x2, y2, ...
and[x1, y1, x2, y2, ...]
, but also(x1, y1), (x2, y2), ...
and[(x1, y1), (x2, y2), ...]
.gh-98040: Remove more deprecated importlib APIs:
find_loader()
,find_module()
,importlib.abc.Finder
,pkgutil.ImpImporter
,pkgutil.ImpLoader
.gh-96522: Fix potential deadlock in pty.spawn()
gh-96534: Support divert(4) added in FreeBSD 14.
gh-87474: Fix potential file descriptor leaks in
subprocess.Popen
.gh-94906: Support multiple steps in
math.nextafter()
. Patch by Shantanu Jain and Matthias Gorgens.gh-51574: Make
tempfile.mkdtemp()
return absolute paths when its dir parameter is relative.gh-94518: Convert private
_posixsubprocess.fork_exec()
to use Argument Clinic.gh-92184: When creating zip files using
zipfile
,os.altsep
, if notNone
, will always be treated as a path separator even when it is not/
. Patch by Carey Metcalfe.bpo-46797: Deprecation warnings are now emitted for
ast.Num
,ast.Bytes
,ast.Str
,ast.NameConstant
andast.Ellipsis
. These have been documented as deprecated since Python 3.8, and will be removed in Python 3.14.bpo-44844: Enables
webbrowser
to detect and launch Microsoft Edge browser.bpo-45606: Fixed the bug in
pathlib.Path.glob()
-- previously a dangling symlink would not be found by this method when the pattern is an exact match, but would be found when the pattern contains a wildcard or the recursive wildcard (**
). With this change, a dangling symlink will be found in both cases.bpo-23041: Add
QUOTE_STRINGS
andQUOTE_NOTNULL
to the suite ofcsv
module quoting styles.bpo-24964: Added
http.client.HTTPConnection.get_proxy_response_headers()
that provides access to the HTTP headers on a proxy server response to theCONNECT
request.bpo-17258:
multiprocessing
now supports stronger HMAC algorithms for inter-process connection authentication rather than only HMAC-MD5.bpo-39744: Make
asyncio.subprocess.Process.communicate()
close the subprocess's stdin even when called withinput=None
.bpo-22708: http.client CONNECT method tunnel improvements: Use HTTP 1.1 protocol; send a matching Host: header with CONNECT, if one is not provided; convert IDN domain names to Punycode. Patch by Michael Handler.
Documentation¶
gh-67056: Document that the effect of registering or unregistering an
atexit
cleanup function from within a registered cleanup function is undefined.gh-103629: Mention the new way of typing
**kwargs
withUnpack
andTypedDict
introduced in PEP 692.gh-48241: Clarifying documentation about the url parameter to urllib.request.urlopen and urllib.request.Request needing to be encoded properly.
gh-86094: Add support for Unicode Path Extra Field in ZipFile. Patch by Yeojin Kim and Andrea Giudiceandrea
gh-99202: Fix extension type from documentation for compiling in C++20 mode
Tests¶
gh-104494: Update
test_pack_configure_in
andtest_place_configure_in
for changes to error message formatting in Tk 8.7.gh-104461: Run test_configure_screen on X11 only, since the
DISPLAY
environment variable and-screen
option for toplevels are not useful on Tk for Win32 or Aqua.gh-86275: Added property-based tests to the
zoneinfo
tests, along with stubs for thehypothesis
interface. (Patch by Paul Ganssle)gh-103329: Regression tests for the behaviour of
unittest.mock.PropertyMock
were added.gh-102795: fix use of poll in test_epoll's test_control_and_wait
gh-75729: Fix the
os.spawn*
tests failing on Windows when the working directory or interpreter path contains spaces.
Build¶
gh-101282: BOLT optimization is now applied to the libpython shared library if building a shared library. BOLT instrumentation and application settings can now be influenced via the
BOLT_INSTRUMENT_FLAGS
andBOLT_APPLY_FLAGS
configure variables.gh-99017:
PYTHON_FOR_REGEN
now require Python 3.10 or newer.gh-104490: Define
.PHONY
/ virtual make targets consistently and properly.gh-104106: Add gcc fallback of mkfifoat/mknodat for macOS. Patch by Donghee Na.
gh-103532: The
TKINTER_PROTECT_LOADTK
macro is no longer defined or used in the_tkinter
module. It was previously only defined when building against Tk 8.4.13 and older, but Tk older than 8.5.12 has been unsupported since gh-91152.gh-99069: Extended workaround defining
static_assert
when missing from the libc headers to all clang and gcc builds. In particular, this fixes building on macOS <= 10.10.gh-100220: Changed the default value of the
SHELL
Makefile variable from/bin/sh
to/bin/sh -e
to ensure that complex recipes correctly fail after an error. Previously,make install
could fail to install some files and yet return a successful result.gh-90656: Add platform triplets for 64-bit LoongArch:
loongarch64-linux-gnusf
loongarch64-linux-gnuf32
loongarch64-linux-gnu
Patch by Zhang Na.
Windows¶
gh-104623: Update Windows installer to use SQLite 3.42.0.
gh-82814: Fix a potential
[Errno 13] Permission denied
when usingshutil.copystat()
within Windows Subsystem for Linux (WSL) on a mounted filesystem by addingerrno.EACCES
to the list of ignored errors within the internal implementation.gh-103088: Fix virtual environment
activate
script having incorrect line endings for Cygwin.gh-103088: Fixes venvs not working in bash on Windows across different disks
gh-102997: Update Windows installer to use SQLite 3.41.2.
gh-88013: Fixed a bug where
TypeError
was raised when callingntpath.realpath()
with a bytes parameter in some cases.
macOS¶
gh-99834: Update macOS installer to Tcl/Tk 8.6.13.
gh-104623: Update macOS installer to SQLite 3.42.0.
gh-103545: Add
os.PRIO_DARWIN_THREAD
,os.PRIO_DARWIN_PROCESS
,os.PRIO_DARWIN_BG
andos.PRIO_DARWIN_NONUI
. These can be used withos.setpriority
to run the process at a lower priority and make use of the efficiency cores on Apple Silicon systems.gh-104180: Support reading SOCKS proxy configuration from macOS System Configuration. Patch by Sam Schott.
gh-60436: update curses textbox to additionally handle backspace using the
curses.ascii.DEL
key press.gh-102997: Update macOS installer to SQLite 3.41.2.
IDLE¶
Tools/Demos¶
C API¶
gh-101291: Added unstable C API for extracting the value of "compact" integers:
PyUnstable_Long_IsCompact()
andPyUnstable_Long_CompactValue()
.gh-104109: We've added
Py_NewInterpreterFromConfig()
andPyInterpreterConfig
to the public C-API (but not the stable ABI; not yet at least). The new function may be used to create a new interpreter with various features configured. The function was added to support PEP 684 (per-interpreter GIL).gh-103968:
PyType_FromSpec()
and its variants now allow creating classes whose metaclass overridestp_new
. Thetp_new
is ignored. This behavior is deprecated and will be disallowed in 3.14+. The newPyType_FromMetaclass()
already disallows it.gh-103743: Add
PyUnstable_Object_GC_NewWithExtraData()
function that can be used to allocate additional memory after an object for data not managed by Python.gh-103295: Introduced
PyUnstable_WritePerfMapEntry()
,PyUnstable_PerfMapState_Init()
andPyUnstable_PerfMapState_Fini()
. These allow extension modules (JIT compilers in particular) to write to perf-map files in a thread safe manner. The Python support for the Linux perf profiler also uses these APIs to write entries in the perf-map file.gh-103509: Added C API for extending types whose instance memory layout is opaque:
PyType_Spec.basicsize
can now be zero or negative,PyObject_GetTypeData()
can be used to get subclass-specific data, andPy_TPFLAGS_ITEMS_AT_END
can be used to safely extend variable-size objects. See PEP 697 for details.gh-103091: Add a new C-API function to eagerly assign a version tag to a PyTypeObject:
PyUnstable_Type_AssignVersionTag()
.gh-101408:
PyObject_GC_Resize
should calculate preheader size if needed. Patch by Donghee Na.gh-98836: Add support of more formatting options (left aligning, octals, uppercase hexadecimals,
intmax_t
,ptrdiff_t
,wchar_t
C strings, variable width and precision) inPyUnicode_FromFormat()
andPyUnicode_FromFormatV()
.gh-96803: Add unstable C-API functions to get the code object, lasti and line number from the internal
_PyInterpreterFrame
in the limited API. The functions are:PyCodeObject * PyUnstable_InterpreterFrame_GetCode(struct _PyInterpreterFrame *frame)
int PyUnstable_InterpreterFrame_GetLasti(struct _PyInterpreterFrame *frame)
int PyUnstable_InterpreterFrame_GetLine(struct _PyInterpreterFrame *frame)
Python 3.12.0 alpha 7¶
Release date: 2023-04-04
Core and Builtins¶
gh-102192: Deprecated
_PyErr_ChainExceptions
in favour of_PyErr_ChainExceptions1
.gh-89987: Reduce the number of inline
CACHE
entries forBINARY_SUBSCR
.gh-102859: Removed
JUMP_IF_FALSE_OR_POP
andJUMP_IF_TRUE_OR_POP
instructions.gh-101975: Fixed
stacktop
value on tracing entries to avoid corruption on garbage collection.gh-102778: Add
sys.last_exc
and deprecatesys.last_type
,sys.last_value
andsys.last_traceback
, which hold the same information in its legacy form.gh-100982: Replace all occurrences of
COMPARE_AND_BRANCH
withCOMPARE_OP
.gh-102701: Fix overflow when creating very large dict.
gh-102755: Add
PyErr_DisplayException()
which takes just an exception instance, to replace the legacyPyErr_Display()
which takes the(typ, exc, tb)
triplet.gh-102594: Add note to exception raised in
PyErr_SetObject
when normalization fails.gh-90997: Shrink the number of inline
CACHE
entries used byLOAD_GLOBAL
.gh-102491: Improve import time of
platform
by removing IronPython version parsing. The IronPython version parsing was not functional (see https://github.com/IronLanguages/ironpython3/issues/1667).gh-101291: Rearrage bits in first field (after header) of PyLongObject. * Bits 0 and 1: 1 - sign. I.e. 0 for positive numbers, 1 for zero and 2 for negative numbers. * Bit 2 reserved (probably for the immortal bit) * Bits 3+ the unsigned size.
This makes a few operations slightly more efficient, and will enable a more compact and faster 2s-complement representation of most ints in future.
gh-102397: Fix segfault from race condition in signal handling during garbage collection. Patch by Kumar Aditya.
gh-102406:
codecs
encoding/decoding errors now get the context information (which operation and which codecs) attached as PEP 678 notes instead of through chaining a new instance of the exception.gh-102281: Fix potential nullptr dereference and use of uninitialized memory in fileutils. Patch by Max Bachmann.
gh-102300: Reuse operands with refcount of 1 in float specializations of BINARY_OP.
gh-102213: Fix performance loss when accessing an object's attributes with
__getattr__
defined.gh-102255: Improve build support for the Xbox. Patch by Max Bachmann.
gh-102027: Fix SSE2 and SSE3 detection in
_blake2
internal module. Patch by Max Bachmann.gh-101865: Deprecate
co_lnotab
in code objects, schedule it for removal in Python 3.14bpo-1635741: Adapt
_pickle
to PEP 687. Patch by Mohamed Koubaa and Erlend Aasland.
Library¶
gh-103085: Pure python
locale.getencoding()
will not warn deprecation.gh-103068: It's no longer possible to register conditional breakpoints in
Pdb
that raiseSyntaxError
. Patch by Tian Gao.gh-102549: Don't ignore exceptions in member type creation.
gh-103056: Ensure final
_generate_next_value_
is astaticmethod
.gh-103046: Display current line label correctly in
dis
whenshow_caches
is False andlasti
points to a CACHE entry.gh-102433:
isinstance()
checks againstruntime-checkable protocols
now useinspect.getattr_static()
rather thanhasattr()
to lookup whether attributes exist. This means that descriptors and__getattr__()
methods are no longer unexpectedly evaluated duringisinstance()
checks against runtime-checkable protocols. However, it may also mean that some objects which used to be considered instances of a runtime-checkable protocol may no longer be considered instances of that protocol on Python 3.12+, and vice versa. Most users are unlikely to be affected by this change. Patch by Alex Waygood.gh-103023: It's no longer possible to register expressions to display in
Pdb
that raiseSyntaxError
. Patch by Tian Gao.gh-102947: Improve traceback when
dataclasses.fields()
is called on a non-dataclass. Patch by Alex Waygoodgh-102780: The
asyncio.Timeout
context manager now works reliably even when performing cleanup due to task cancellation. Previously it could raise aCancelledError
instead of anTimeoutError
in such cases.gh-102871: Remove support for obsolete browsers from
webbrowser
. Removed browsers include Grail, Mosaic, Netscape, Galeon, Skipstone, Iceape, Firebird, and Firefox versions 35 and below.gh-102839: Improve performance of
math.log()
arguments handling by removing the argument clinic.gh-102828: Add the
onexc
arg toshutil.rmtree()
, which is likeonerror
but expects an exception instance rather than an exc_info tuple. Deprecateonerror
.gh-88965: typing: Fix a bug relating to substitution in custom classes generic over a
ParamSpec
. Previously, if theParamSpec
was substituted with a parameters list that itself contained aTypeVar
, theTypeVar
in the parameters list could not be subsequently substituted. This is now fixed.Patch by Nikita Sobolev.
gh-76846: Fix issue where
__new__()
and__init__()
methods ofpathlib.PurePath
andPath
subclasses were not called in some circumstances.gh-78530:
asyncio.wait()
now accepts generators yielding tasks. Patch by Kumar Aditya.gh-102748:
asyncio.iscoroutine()
now returnsFalse
for generators asasyncio
does not support legacy generator-based coroutines. Patch by Kumar Aditya.gh-102670: Optimized fmean(), correlation(), covariance(), and linear_regression() using the new math.sumprod() function.
gh-102615: Typing: Improve the
repr
of generic aliases for classes generic over aParamSpec
. (Use square brackets to represent a parameter list.)gh-100112:
asyncio.Task.get_coro()
now always returns a coroutine when wrapping an awaitable object. Patch by Kumar Aditya.gh-102578: Speed up setting or deleting mutable attributes on non-dataclass subclasses of frozen dataclasses. Due to the implementation of
__setattr__
and__delattr__
for frozen dataclasses, this previously had a time complexity of O(n). It now has a time complexity of O(1).gh-102519: Add
os.listdrives()
,os.listvolumes()
andos.listmounts()
functions on Windows for enumerating drives, volumes and mount pointsgh-74468: Attribute name of the extracted
tarfile
file object now holds filename of itself rather than of the archive it is contained in. Patch by Oleg Iarygin.gh-102378: Private helper method
inspect._signature_strip_non_python_syntax
will no longer strip/
from the input string.gh-79940: Add
inspect.getasyncgenstate()
andinspect.getasyncgenlocals()
. Patch by Thomas Krennwallner.gh-102103: Add
module
argument todataclasses.make_dataclass()
and make classes produced by it pickleable.gh-102069: Fix
__weakref__
descriptor generation for custom dataclasses.gh-102038: Skip a
stat
insite
if we have already found apyvenv.cfg
gh-98886: Fix issues when defining dataclasses that have fields with specific underscore names that aren't clearly reserved by
dataclasses
.gh-101673: Fix a
pdb
bug wherell
clears the changes to local variables.gh-101313: Added -h and --help arguments to the webbrowser CLI
gh-100372:
ssl.SSLContext.load_verify_locations()
no longer incorrectly accepts some cases of trailing data when parsing DER.gh-89727: Fix pathlib.Path.walk RecursionError on deep directory trees by rewriting it using iteration instead of recursion.
gh-100131: Added an optional
delete
keyword argument totempfile.TemporaryDirectory
.gh-48330: Added
--durations
command line option, showing the N slowest test cases.unittest.TextTestRunner
andunittest.TextTestResult
constructors accept a new durations keyword argument. Subclasses should take this into account or accept**kwargs
. Addedunittest.TestResult.addDuration()
method andunittest.TestResult.collectedDurations
attribute.(Contributed by Giampaolo Rodola)
gh-98169: Fix
dataclasses.astuple()
crash whencollections.defaultdict
is present in the attributes.gh-96931: Fix incorrect results from
ssl.SSLSocket.shared_ciphers()
gh-95495: When built against OpenSSL 3.0, the
ssl
module had a bug where it reported unauthenticated EOFs (i.e. without close_notify) as a clean TLS-level EOF. It now raisesSSLEOFError
, matching the behavior in previous versions of OpenSSL. Theoptions
attribute onSSLContext
also no longer includesOP_IGNORE_UNEXPECTED_EOF
by default. This option may be set to specify the previous OpenSSL 3.0 behavior.gh-94684: Now
uuid.uuid3()
anduuid.uuid5()
functions supportbytes
objects as their name argument.gh-94440: Fix a
concurrent.futures.process
bug whereProcessPoolExecutor
shutdown could hang after a future has been quickly submitted and canceled.gh-72346: Added deprecation warning to isdst parameter of
email.utils.localtime()
.bpo-36305: Fix handling of Windows filenames that resemble drives, such as
./a:b
, inpathlib
.
Documentation¶
gh-103112: Add docstring to
http.client.HTTPResponse.read()
to fixpydoc
output.
Tests¶
Build¶
Windows¶
gh-102690: Update
webbrowser
to fall back to Microsoft Edge instead of Internet Explorer.gh-99726: Improves correctness of stat results for Windows, and uses faster API when available
Tools/Demos¶
gh-102809:
Misc/gdbinit
was removed.
C API¶
gh-102013: Add a new (unstable) C-API function for iterating over GC'able objects using a callback:
PyUnstable_VisitObjects
.
Python 3.12.0 alpha 6¶
Release date: 2023-03-07
Security¶
gh-99108: Replace builtin hashlib implementations of MD5 and SHA1 with verified ones from the HACL* project.
gh-101727: Updated the OpenSSL version used in Windows and macOS binary release builds to 1.1.1t to address CVE 2023-0286, CVE 2022-4303, and CVE 2022-4303 per the OpenSSL 2023-02-07 security advisory.
gh-99108: Replace the builtin
hashlib
implementations of SHA2-384 and SHA2-512 originally from LibTomCrypt with formally verified, side-channel resistant code from the HACL* project. The builtins remain a fallback only used when OpenSSL does not provide them.gh-101283:
subprocess.Popen
now uses a safer approach to findcmd.exe
when launching withshell=True
. Patch by Eryk Sun, based on a patch by Oleg Iarygin.
Core and Builtins¶
gh-102493: Fix regression in semantics of normalisation in
PyErr_SetObject
.gh-102416: Do not memoize incorrectly automatically generated loop rules in the parser. Patch by Pablo Galindo.
gh-102356: Fix a bug that caused a crash when deallocating deeply nested filter objects. Patch by Marta Gómez Macías.
gh-102336: Cleanup Windows 7 specific special handling. Patch by Max Bachmann.
gh-102250: Fixed a segfault occurring when the interpreter calls a
__bool__
method that raises.gh-102126: Fix deadlock at shutdown when clearing thread states if any finalizer tries to acquire the runtime head lock. Patch by Kumar Aditya.
gh-102027: Use
GetCurrentProcessId
on Windows whengetpid
is unavailable. Patch by Max Bachmann.gh-102056: Fix error handling bugs in interpreter's exception printing code, which could cause a crash on infinite recursion.
gh-100982: Restrict the scope of the
FOR_ITER_RANGE
instruction to the scope of the originalFOR_ITER
instruction, to allow instrumentation.gh-101967: Fix possible segfault in
positional_only_passed_as_keyword
function, when new list created.gh-101952: Fix possible segfault in
BUILD_SET
opcode, when new set created.gh-74895:
socket.getaddrinfo
no longer raisesOverflowError
forint
port values outside of the C long range. Out of range values are left up to the underlying string based C library API to report. Asocket.gaierror
SAI_SERVICE
may occur instead, or no error at all as not all platform C libraries generate an error.gh-101799: Add
CALL_INTRINSIC_2
and use it instead ofPREP_RERAISE_STAR
.gh-101857: Fix xattr support detection on Linux systems by widening the check to linux, not just glibc. This fixes support for musl.
gh-84783: Make the slice object hashable. Patch by Will Bradshaw and Furkan Onder.
gh-87849: Change the
SEND
instruction to leave the receiver on the stack. This allows the specialized form ofSEND
to skip the chain of C calls and jump directly to theRESUME
in the generator or coroutine.gh-101765: Fix SystemError / segmentation fault in iter
__reduce__
when internal access ofbuiltins.__dict__
keys mutates the iter object.gh-101430: Update
tracemalloc
to handle presize of object properly. Patch by Donghee Na.gh-101696: Invalidate type version tag in
_PyStaticType_Dealloc
for static types, avoiding bug where a false cache hit could crash the interpreter. Patch by Kumar Aditya.gh-101632: Adds a new
RETURN_CONST
instruction.gh-100719: Remove gi_code field from generator (and coroutine and async generator) objects as it is redundant. The frame already includes a reference to the code object.
gh-98627: When an interpreter is configured to check (and only then), importing an extension module will now fail when the extension does not support multiple interpreters (i.e. doesn't implement PEP 489 multi-phase init). This does not apply to the main interpreter, nor to subinterpreters created with
Py_NewInterpreter()
.
Library¶
gh-102302: Micro-optimise hashing of
inspect.Parameter
, reducing the time it takes to hash an instance by around 40%.gh-101979: Fix a bug where parentheses in the
metavar
argument toargparse.ArgumentParser.add_argument()
were dropped. Patch by Yeojin Kim.gh-91038:
platform.platform()
now has boolean default arguments.gh-81652: Add
mmap.MAP_ALIGNED_SUPER
FreeBSD andmmap.MAP_CONCEAL
OpenBSD constants tommap
. Patch by Yeojin Kim.gh-101961: For the binary mode,
fileinput.hookcompressed()
doesn't set theencoding
value even if the value isNone
. Patch by Gihwan Kim.gh-101936: The default value of
fp
becomesio.BytesIO
ifHTTPError
is initialized without a designatedfp
parameter. Patch by Long Vo.gh-101566: In zipfile, sync Path with zipp 3.14, including fix for extractall on the underlying zipfile after being wrapped in
Path
.gh-97930: Apply changes from importlib_resources 5.12, including fix for
MultiplexedPath
to support directories in multiple namespaces (python/importlib_resources#265).gh-101997: Upgrade pip wheel bundled with ensurepip (pip 23.0.1)
gh-99108: The built-in extension modules for
hashlib
SHA2 algorithms, used when OpenSSL does not provide them, now live in a single internal_sha2
module instead of separate_sha256
and_sha512
modules.gh-101892: Callable iterators no longer raise
SystemError
when the callable object exhausts the iterator but forgets to either return a sentinel value or raiseStopIteration
.gh-87634: Remove locking behavior from
functools.cached_property()
.gh-97786: Fix potential undefined behaviour in corner cases of floating-point-to-time conversions.
gh-101517: Fixed bug where
bdb
looks up the source line withlinecache
with alineno=None
, which causes it to fail with an unhandled exception.gh-101773: Optimize
fractions.Fraction
for small components. The private argument_normalize
of thefractions.Fraction
constructor has been removed.gh-101693: In
sqlite3.Cursor.execute()
,DeprecationWarning
is now emitted when named placeholders are used together with parameters supplied as a sequence instead of as adict
. Starting from Python 3.14, using named placeholders with parameters supplied as a sequence will raise aProgrammingError
. Patch by Erlend E. Aasland.gh-101446: Change repr of
collections.OrderedDict
to use regular dictionary formatting instead of pairs of keys and values.gh-101362: Speed up
pathlib.PurePath
construction by handling arguments more uniformly. When apathlib.Path
argument is supplied, we use its string representation rather than joining its parts withos.path.join()
.gh-101362: Speed up
pathlib.PurePath
construction by callingos.path.join()
only when two or more arguments are given.gh-101362: Speed up
pathlib.Path
construction by running the path flavour compatibility check only when pathlib is imported.gh-85984: Refactored the implementation of
pty.fork()
to useos.login_tty()
.A
DeprecationWarning
is now raised bypty.master_open()
andpty.slave_open()
. They were undocumented and deprecated long long ago in the docstring in favor ofpty.openpty()
.gh-101561: Add a new decorator
typing.override()
. See PEP 698 for details. Patch by Steven Troxler.gh-101360: Fix anchor matching in
pathlib.PureWindowsPath.match()
. Path and pattern anchors are now matched withfnmatch
, just like other path parts. This allows patterns such as"*:/Users/*"
to be matched.gh-101277: Remove global state from
itertools
module (PEP 687). Patches by Erlend E. Aasland.gh-100809: Fix handling of drive-relative paths (like 'C:' and 'C:foo') in
pathlib.Path.absolute()
. This method now uses the OS API to retrieve the correct current working directory for the drive.gh-99138: Apply PEP 687 to
zoneinfo
. Patch by Erlend E. Aasland.gh-96764:
asyncio.wait_for()
now usesasyncio.timeout()
as its underlying implementation. Patch by Kumar Aditya.gh-88233: Correctly preserve "extra" fields in
zipfile
regardless of their ordering relative to a zip64 "extra."bpo-23224: Fix segfaults when creating
lzma.LZMADecompressor
andbz2.BZ2Decompressor
objects without calling__init__()
, and fix leakage of locks and internal buffers when calling the__init__()
methods oflzma.LZMADecompressor
,lzma.LZMACompressor
,bz2.BZ2Compressor
, andbz2.BZ2Decompressor
objects multiple times.
Documentation¶
gh-85417: Update
cmath
documentation to clarify behaviour on branch cuts.gh-97725: Fix
asyncio.Task.print_stack()
description forfile=None
. Patch by Oleg Iarygin.
Tests¶
gh-102019: Fix deadlock on shutdown if
test_current_{exception,frames}
fails. Patch by Jacob Bower.gh-85984: Utilize new "winsize" functions from termios in pty tests.
gh-89792:
test_tools
now copies up to 10x less source data to a temporary directory during thefreeze
test by ignoring git metadata and other artifacts. It also limits its python build parallelism based on os.cpu_count instead of hard coding it as 8 cores.
Build¶
gh-99942: On Android, in a static build, python-config in embed mode no longer incorrectly reports a library to link to.
gh-99942: On Android, python.pc now correctly reports the library to link to, the same as python-config.sh.
gh-100221: Fix creating install directories in
make sharedinstall
if they exist outsideDESTDIR
already.gh-96821: Explicitly mark C extension modules that need defined signed integer overflow, and add a configure option
--with-strict-overflow
. Patch by Matthias Görgens and Shantanu Jain.
Windows¶
gh-102344: Implement
winreg.QueryValue
usingQueryValueEx
andwinreg.SetValue
usingSetValueEx
. Patch by Max Bachmann.gh-101881: Handle read and write operations on non-blocking pipes properly on Windows.
gh-101881: Add support for the os.get_blocking() and os.set_blocking() functions on Windows.
gh-101849: Ensures installer will correctly upgrade existing
py.exe
launcher installs.gh-101763: Updates copy of libffi bundled with Windows installs to 3.4.4.
gh-101759: Update Windows installer to SQLite 3.40.1.
gh-101614: Correctly handle extensions built against debug binaries that reference
python3_d.dll
.gh-101196: The functions
os.path.isdir
,os.path.isfile
,os.path.islink
andos.path.exists
are now 13% to 28% faster on Windows, by making fewer Win32 API calls.
macOS¶
gh-101759: Update macOS installer to SQLite 3.40.1.
C API¶
gh-101907: Removes use of non-standard C++ extension in public header files.
gh-99293: Document that the Py_TPFLAGS_VALID_VERSION_TAG is an internal feature, should not be used, and will be removed.
gh-101578: Add
PyErr_GetRaisedException()
andPyErr_SetRaisedException()
for saving and restoring the current exception. These functions return and accept a single exception object, rather than the triple arguments of the now-deprecatedPyErr_Fetch()
andPyErr_Restore()
. This is less error prone and a bit more efficient.Add
PyException_GetArgs()
andPyException_SetArgs()
as convenience functions for retrieving and modifying theargs
passed to the exception's constructor.gh-91744: Introduced the Unstable C API tier, marking APi that is allowed to change in minor releases without a deprecation period. See PEP 689 for details.
Python 3.12.0 alpha 5¶
Release date: 2023-02-07
Security¶
Core and Builtins¶
gh-92173: Fix the
defs
andkwdefs
arguments toPyEval_EvalCodeEx()
and a reference leak in that function.gh-59956: The GILState API is now partially compatible with subinterpreters. Previously,
PyThreadState_GET()
andPyGILState_GetThisThreadState()
would get out of sync, causing inconsistent behavior and crashes.gh-101400: Fix wrong lineno in exception message on
continue
orbreak
which are not in a loop. Patch by Donghee Na.gh-101372: Fix
is_normalized()
to properly handle the UCD 3.2.0 cases. Patch by Donghee Na.gh-101266: Fix
sys.getsizeof()
reporting forint
subclasses.gh-101291: Refactor the
PyLongObject
struct into a normal Python object header and aPyLongValue
struct.gh-101046: Fix a possible memory leak in the parser when raising
MemoryError
. Patch by Pablo Galindogh-101037: Fix potential memory underallocation issue for instances of
int
subclasses with value zero.gh-100762: Record the (virtual) exception block depth in the oparg of
YIELD_VALUE
. Use this to avoid the expensivethrow()
when closing generators (and coroutines) that can be closed trivially.gh-100982: Adds a new
COMPARE_AND_BRANCH
instruction. This is a bit more efficient when performing a comparison immediately followed by a branch, and restores the design intent of PEP 659 that specializations are local to a single instruction.gh-100942: Fixed segfault in property.getter/setter/deleter that occurred when a property subclass overrode the
__new__
method to return a non-property instance.gh-100923: Remove the
mask
cache entry for theCOMPARE_OP
instruction and embed the mask into the oparg.gh-100892: Fix race while iterating over thread states in clearing
threading.local
. Patch by Kumar Aditya.gh-91351: Fix a case where re-entrant imports could corrupt the import deadlock detection code and cause a
KeyError
to be raised out ofimportlib/_bootstrap
. In addition to the straightforward cases, this could also happen when garbage collection leads to a warning being emitted -- as happens when it collects an open socket or file)gh-100726: Optimize construction of
range
object for medium size integers.gh-100712: Added option to build cpython with specialization disabled, by setting
ENABLE_SPECIALIZATION=False
inopcode
, followed bymake regen-all
.bpo-32780: Inter-field padding is now inserted into the PEP3118 format strings obtained from
ctypes.Structure
objects, reflecting their true representation in memory.
Library¶
gh-101541: [Enum] - fix psuedo-flag creation
gh-101570: Upgrade pip wheel bundled with ensurepip (pip 23.0)
gh-101323: Fix a bug where errors where not thrown by zlib._ZlibDecompressor if encountered during decompressing.
gh-101317: Add ssl_shutdown_timeout parameter for
asyncio.StreamWriter.start_tls()
.gh-101326: Fix regression when passing
None
as second or third argument toFutureIter.throw
.gh-92123: Adapt the
_elementtree
extension module to multi-phase init (PEP 489). Patches by Erlend E. Aasland.gh-100795: Avoid potential unexpected
freeaddrinfo
call (double free) insocket
when when a libcgetaddrinfo()
implementation leaves garbage in an output pointer when returning an error. Original patch by Sergey G. Brester.gh-101143: Remove unused references to
TimerHandle
inasyncio.base_events.BaseEventLoop._add_callback
.gh-101144: Make
zipfile.Path.open()
andzipfile.Path.read_text()
also acceptencoding
as a positional argument. This was the behavior in Python 3.9 and earlier. 3.10 introduced a regression where supplying it as a positional argument would lead to aTypeError
.gh-94518: Group-related variables of
_posixsubprocess
module are renamed to stress that supplimentary group affinity is added to a fork, not replace the inherited ones. Patch by Oleg Iarygin.gh-101015: Fix
typing.get_type_hints()
on'*tuple[...]'
and*tuple[...]
. It must not drop theUnpack
part.gh-101000: Add
os.path.splitroot()
, which splits a path into a 3-item tuple(drive, root, tail)
. This new function is used bypathlib
to improve the performance of path construction by up to a third.gh-100573: Fix a Windows
asyncio
bug with named pipes where a client doingos.stat()
on the pipe would cause an error in the server that disabled serving future requests.gh-39615:
warnings.warn()
now has the ability to skip stack frames based on code filename prefix rather than only a numericstacklevel
via the newskip_file_prefixes
keyword argument.gh-100750: pass encoding kwarg to subprocess in platform
gh-100160: Emit a deprecation warning in
asyncio.DefaultEventLoopPolicy.get_event_loop()
if there is no current event loop set and it decides to create one.gh-96290: Fix handling of partial and invalid UNC drives in
ntpath.splitdrive()
, and inntpath.normpath()
on non-Windows systems. Paths such as '\server' and '\' are now considered bysplitdrive()
to contain only a drive, and consequently are not modified bynormpath()
on non-Windows systems. The behaviour ofnormpath()
on Windows systems is unaffected, as native OS APIs are used. Patch by Eryk Sun, with contributions by Barney Gale.gh-99952: Fix a reference undercounting issue in
ctypes.Structure
withfrom_param()
results larger than a C pointer.gh-67790: Add float-style formatting support for
fractions.Fraction
instances.gh-86682: Ensure runtime-created collections have the correct module name using the newly added (internal)
sys._getframemodulename()
.gh-88597:
uuid
now has a command line interface. Trypython -m uuid -h
.gh-60580:
ctypes.wintypes.BYTE
definition changed fromc_byte
toc_ubyte
to match Windows SDK. Patch by Anatoly Techtonik and Oleg Iarygin.gh-94518:
_posixsubprocess
now initializes all UID and GID variables using a reserved-1
value instead of a separate flag. Patch by Oleg Iarygin.bpo-38941: The
xml.etree.ElementTree
module now emitsDeprecationWarning
when testing the truth value of anxml.etree.ElementTree.Element
. Before, the Python implementation emittedFutureWarning
, and the C implementation emitted nothing.bpo-40077: Convert
elementtree
types to heap types. Patch by Erlend E. Aasland.bpo-29847: Fix a bug where
pathlib.Path
accepted and ignored keyword arguments. Patch provided by Yurii Karabas.gh-77772:
ctypes.CDLL
,ctypes.OleDLL
,ctypes.WinDLL
, andctypes.PyDLL
now accept path-like objects as theirname
argument. Patch by Robert Hoelzl.
Documentation¶
gh-88324: Reword
subprocess
to emphasize default behavior of stdin, stdout, and stderr arguments. Remove inaccurate statement about child file handle inheritance.
Tests¶
gh-101334:
test_tarfile
has been updated to pass when run as a high UID.
Build¶
gh-101282: Update BOLT configuration not to use deprecated usage of
--split functions
. Patch by Donghee Na.gh-101522: Allow overriding Windows dependencies versions and paths using MSBuild properties.
gh-77532: Minor fixes to allow building with
PlatformToolset=ClangCL
on Windows.gh-101152: In accordance with PEP 699, the
ma_version_tag
field inPyDictObject
is deprecated for extension modules. Accessing this field will generate a compiler warning at compile time. This field will be removed in Python 3.14.gh-100340: Allows -Wno-int-conversion for wasm-sdk 17 and onwards, thus enables building WASI builds once against the latest sdk.
gh-101060: Conditionally add
-fno-reorder-blocks-and-partition
in configure. Effectively fixes--enable-bolt
when using Clang, as this appears to be a GCC-only flag.gh-98705:
__bool__
is defined in AIX system header files which breaks the build in AIX, so undefine it.gh-98636: Fix a regression in detecting
gdbm_compat
library for the_gdbm
module build.gh-96305:
_aix_support
now uses a simple code to get platform details rather than the now non-existent_bootsubprocess
during bootstrap.
Windows¶
gh-101543: Ensure the install path in the registry is only used when the standard library hasn't been located in any other way.
gh-101467: The
py.exe
launcher now correctly filters when only a single runtime is installed. It also correctly handles prefix matches on tags so that-3.1
does not match3.11
, but would still match3.1-32
.gh-99834: Updates bundled copy of Tcl/Tk to 8.6.13.0
gh-101135: Restore ability to launch older 32-bit versions from the
py.exe
launcher when both 32-bit and 64-bit installs of the same version are available.gh-82052: Fixed an issue where writing more than 32K of Unicode output to the console screen in one go can result in mojibake.
gh-100320: Ensures the
PythonPath
registry key from an install is used when launching from a different copy of Python that relies on an existing install to provide a copy of its modules and standard library.gh-100247: Restores support for the
py.exe
launcher finding shebang commands in its configuration file using the full command name.
Python 3.12.0 alpha 4¶
Release date: 2023-01-10
Core and Builtins¶
gh-100776: Fix misleading default value in
input()
's__text_signature__
.gh-99005: Remove
UNARY_POSITIVE
,ASYNC_GEN_WRAP
andLIST_TO_TUPLE
, replacing them with intrinsics.gh-99005: Add new
CALL_INTRINSIC_1
instruction. RemoveIMPORT_STAR
,PRINT_EXPR
andSTOPITERATION_ERROR
, replacing them with theCALL_INTRINSIC_1
instruction.gh-100288: Remove the LOAD_ATTR_METHOD_WITH_DICT specialized instruction. Stats show it is not useful.
gh-100720: Added
_PyFrame_NumSlotsForCodeObject
, which returns the number of slots needed in a frame for a given code object.gh-100719: Removed the co_nplaincellvars field from the code object, as it is redundant.
gh-100637: Fix
int.__sizeof__()
calculation to include the 1-elementob_digit
array for0
andFalse
.gh-100649: Update the native_thread_id field of PyThreadState after fork.
gh-100126: Fix an issue where "incomplete" frames could be briefly visible to C code while other frames are being torn down, possibly resulting in corruption or hard crashes of the interpreter while running finalizers.
gh-87447: Fix
SyntaxError
on comprehension rebind checking with names that are not actually redefined.Now reassigning
b
in[(b := 1) for a, b.prop in some_iter]
is allowed. Reassigninga
is still disallowed as per PEP 572.gh-100268: Add
int.is_integer()
to improve duck type compatibility betweenint
andfloat
.gh-100425: Improve the accuracy of
sum()
with compensated summation.gh-100374: Fix incorrect result and delay in
socket.getfqdn()
. Patch by Dominic Socular.gh-100357: Convert
vars
,dir
,next
,getattr
, anditer
to argument clinic.gh-100117: Improve the output of
codeobject.co_lines()
by emitting only one entry for each line range.gh-90043: Handle NaNs when specializing
COMPARE_OP
forfloat
values.gh-100222: Redefine the
_Py_CODEUNIT
typedef as a union to describe its layout to the C compiler, avoiding type punning and improving clarity.gh-99955: Internal compiler functions (in compile.c) now consistently return -1 on error and 0 on success.
gh-100188: The
BINARY_SUBSCR_LIST_INT
andBINARY_SUBSCR_TUPLE_INT
instructions are no longer used for negative integers because those instructions always miss when encountering negative integers.gh-99110: Initialize frame->previous in frameobject.c to fix a segmentation fault when accessing frames created by
PyFrame_New()
.gh-94155: Improved the hashing algorithm for code objects, mitigating some hash collisions.
gh-99540:
None
now hashes to a constant value. This is not a requirements change.gh-100143: When built with
--enable-pystats
, stats collection is now off by default. To enable it early at startup, pass the-Xpystats
flag. Stats are now always dumped, even if switched off.gh-100146: Improve
BUILD_LIST
opcode so that it works similarly to theBUILD_TUPLE
opcode, by stealing references from the stack rather than repeatedly using stack operations to set list elements. Implementation details are in a new private API_PyList_FromArraySteal()
.gh-100110: Specialize
FOR_ITER
for tuples.gh-100050: Honor existing errors obtained when searching for mismatching parentheses in the tokenizer. Patch by Pablo Galindo
gh-92216: Improve the performance of
hasattr()
for type objects with a missing attribute.gh-99554: Pack debugging location tables more efficiently during bytecode compilation.
gh-98522: Add an internal version number to code objects, to give better versioning of inner functions and comprehensions, and thus better specialization of those functions. This change is invisible to both Python and C extensions.
gh-94603: Improve performance of
list.pop
for small lists.bpo-32782:
ctypes
arrays of length 0 now report a correct itemsize when amemoryview
is constructed from them, rather than always giving a value of 0.
Library¶
gh-100833: Speed up
math.fsum()
by removing defensivevolatile
qualifiers.gh-100805: Modify
random.choice()
implementation to once again work with NumPy arrays.gh-100813: Add
socket.IP_PKTINFO
constant.gh-100792: Make
email.message.Message.__contains__()
twice as fast.gh-91851: Microoptimizations for
fractions.Fraction.__round__()
,fractions.Fraction.__ceil__()
andfractions.Fraction.__floor__()
.gh-90104: Avoid RecursionError on
repr
if a dataclass field definition has a cyclic reference.gh-100689: Fix crash in
pyexpat
by statically allocatingPyExpat_CAPI
capsule.gh-100740: Fix
unittest.mock.Mock
not respecting the spec for attribute names prefixed withassert
.gh-91219: Change
SimpleHTTPRequestHandler
to support subclassing to provide a different set of index file names instead of using__init__
parameters.gh-100690:
Mock
objects which are not unsafe will now raise anAttributeError
when accessing an attribute that matches the name of an assertion but without the prefixassert_
, e.g. accessingcalled_once
instead ofassert_called_once
. This is in addition to this already happening for accessing attributes with prefixesassert
,assret
,asert
,aseert
, andassrt
.gh-89727: Simplify and optimize
os.walk()
by usingisinstance()
checks to check the top of the stack.gh-100485: Add math.sumprod() to compute the sum of products.
gh-86508: Fix
asyncio.open_connection()
to skip binding to local addresses of different family. Patch by Kumar Aditya.gh-97930:
importlib.resources.files
now accepts a module as an anchor instead of only accepting packages. If a module is passed, resources are resolved adjacent to that module (in the same package or at the package root). The parameter was renamed frompackage
toanchor
with a compatibility shim for those passing by keyword. Additionally, the newanchor
parameter is now optional and will default to the caller's module.gh-100585: Fixed a bug where importlib.resources.as_file was leaving file pointers open
gh-100562: Improve performance of
pathlib.Path.absolute()
by nearly 2x. This comes at the cost of a performance regression inpathlib.Path.cwd()
, which is generally used less frequently in user code.gh-100519: Small simplification of
http.cookiejar.eff_request_host()
that improves readability and better matches the RFC wording.gh-100287: Fix the interaction of
unittest.mock.seal()
withunittest.mock.AsyncMock
.gh-100488: Add
Fraction.is_integer()
to check whether afractions.Fraction
is an integer. This improves duck type compatibility withfloat
andint
.gh-100474:
http.server
now checks that an index page is actually a regular file before trying to serve it. This avoids issues with directories namedindex.html
.gh-100363: Speed up
asyncio.get_running_loop()
by removing redundantgetpid
checks. Patch by Kumar Aditya.gh-78878: Fix crash when creating an instance of
_ctypes.CField
.gh-100348: Fix ref cycle in
asyncio._SelectorSocketTransport
by removing_read_ready_cb
inclose
.gh-100344: Provide C implementation for
asyncio.current_task()
for a 4x-6x speedup.gh-100272: Fix JSON serialization of OrderedDict. It now preserves the order of keys.
gh-83076: Instantiation of
Mock()
andAsyncMock()
is now 3.8x faster.gh-100234: Set a default value of 1.0 for the
lambd
parameter in random.expovariate().gh-100228: A
DeprecationWarning
may be raised whenos.fork()
oros.forkpty()
is called from multi-threaded processes. Forking with threads is unsafe and can cause deadlocks, crashes and subtle problems. Lack of a warning does not indicate that the fork call was actually safe, as Python may not be aware of all threads.gh-100039: Improve signatures for enums and flags.
gh-100133: Fix regression in
asyncio
where a subprocess would sometimes lose data received from pipe.bpo-44592: Fixes inconsistent handling of case sensitivity of extrasaction arg in
csv.DictWriter
.gh-100098: Fix
tuple
subclasses being cast totuple
when used as enum values.gh-85432: Rename the fmt parameter of the pure-Python implementation of
datetime.time.strftime()
to format. Rename the t parameter ofdatetime.datetime.fromtimestamp()
to timestamp. These changes mean the parameter names in the pure-Python implementation now match the parameter names in the C implementation. Patch by Alex Waygood.gh-98778: Update
HTTPError
to be initialized properly, even if thefp
isNone
. Patch by Donghee Na.gh-99925: Unify error messages in JSON serialization between
json.dumps(float('nan'), allow_nan=False)
andjson.dumps(float('nan'), allow_nan=False, indent=<SOMETHING>)
. Now both include the representation of the value that could not be serialized.gh-89727: Fix issue with
os.walk()
where aRecursionError
would occur on deep directory structures by adjusting the implementation ofos.walk()
to be iterative instead of recursive.gh-94943: Add Dataclass support to the
Enum
__repr__()
. When inheriting from adataclass
, only show the field names in the value section of the memberrepr()
, and not the dataclass' class name.gh-83035: Fix
inspect.getsource()
handling of decorator calls with nested parentheses.gh-99576: Fix
.save()
method forLWPCookieJar
andMozillaCookieJar
: saved file was not truncated on repeated save.gh-94912: Add
inspect.markcoroutinefunction()
decorator which manually marks a function as a coroutine for the benefit ofiscoroutinefunction()
.gh-99509: Add PEP 585 support for
multiprocessing.queues.Queue
.gh-99482: Remove
Jython
partial compatibility code from several stdlib modules.gh-99433: Fix
doctest
failure ontypes.MethodWrapperType
in modules.gh-85267: Several improvements to
inspect.signature()
's handling of__text_signature
. - Fixes a case whereinspect.signature()
dropped parameters - Fixes a case whereinspect.signature()
raisedtokenize.TokenError
- Allowsinspect.signature()
to understand defaults involving binary operations of constants -inspect.signature()
is documented as only raisingTypeError
orValueError
, but sometimes raisedRuntimeError
. These cases now raiseValueError
- Removed a dead code pathgh-91166:
asyncio
is optimized to avoid excessive copying when writing to socket and usesendmsg()
if the platform supports it. Patch by Kumar Aditya.gh-98030: Add missing TCP socket options from Linux:
TCP_MD5SIG
,TCP_THIN_LINEAR_TIMEOUTS
,TCP_THIN_DUPACK
,TCP_REPAIR
,TCP_REPAIR_QUEUE
,TCP_QUEUE_SEQ
,TCP_REPAIR_OPTIONS
,TCP_TIMESTAMP
,TCP_CC_INFO
,TCP_SAVE_SYN
,TCP_SAVED_SYN
,TCP_REPAIR_WINDOW
,TCP_FASTOPEN_CONNECT
,TCP_ULP
,TCP_MD5SIG_EXT
,TCP_FASTOPEN_KEY
,TCP_FASTOPEN_NO_COOKIE
,TCP_ZEROCOPY_RECEIVE
,TCP_INQ
,TCP_TX_DELAY
.gh-88500: Reduced the memory usage of
urllib.parse.unquote()
andurllib.parse.unquote_to_bytes()
on large values.gh-96127:
inspect.signature
was raisingTypeError
on call with mock objects. Now it correctly returns(*args, **kwargs)
as inferred signature.gh-95882: Fix a 3.11 regression in
asynccontextmanager()
, which caused it to propagate exceptions with incorrect tracebacks and fix a 3.11 regression incontextmanager()
, which caused it to propagate exceptions with incorrect tracebacks forStopIteration
.gh-78707: Deprecate passing more than one positional argument to
pathlib.PurePath.relative_to()
andis_relative_to()
.gh-92122: Fix reStructuredText syntax errors in docstrings in the
enum
module.gh-91851: Optimize the
Fraction
arithmetics for small components.bpo-24132: Make
pathlib.PurePath
andPath
subclassable (private to start). Previously, attempting to instantiate a subclass resulted in anAttributeError
being raised. Patch by Barney Gale.bpo-40447: Accept
os.PathLike
(such aspathlib.Path
) in thestripdir
arguments ofcompileall.compile_file()
andcompileall.compile_dir()
.bpo-36880: Fix a reference counting issue when a
ctypes
callback with return typepy_object
returnsNone
, which could cause crashes.
Documentation¶
gh-100616: Document existing
attr
parameter tocurses.window.vline()
function incurses
.gh-100472: Remove claim in documentation that the
stripdir
,prependdir
andlimit_sl_dest
parameters ofcompileall.compile_dir()
andcompileall.compile_file()
could bebytes
.bpo-25377: Clarify use of octal format of mode argument in help(os.chmod) as well as help(os.fchmod)
Tests¶
gh-100454: Start running SSL tests with OpenSSL 3.1.0-beta1.
gh-100086: The Python test runner (libregrtest) now logs Python build information like "debug" vs "release" build, or LTO and PGO optimizations. Patch by Victor Stinner.
gh-93018: Make two tests forgiving towards host system libexpat with backported security fixes applied.
Build¶
gh-100540: Removed the
--with-system-ffi
configure
option;libffi
must now always be supplied by the system on all non-Windows platforms. The option has had no effect on non-Darwin platforms for several releases, and in 3.11 only had the non-obvious effect of invokingpkg-config
to findlibffi
and never setting-DUSING_APPLE_OS_LIBFFI
. Now on Darwin platformsconfigure
will first check for the OSlibffi
and then fall back to the same processing as other platforms if it is not found.gh-88267: Avoid exporting Python symbols in linked Windows applications when the core is built as static.
bpo-41916: Allow override of ac_cv_cxx_thread so that cross compiled python can set -pthread for CXX.
Windows¶
gh-100180: Update Windows installer to OpenSSL 1.1.1s
gh-99191: Use
_MSVC_LANG >= 202002L
instead of less-precise_MSC_VER >=1929
to more accurately test for C++20 support inPC/_wmimodule.cpp
.gh-79218: Define
MS_WIN64
for Mingw-w64 64bit, fix cython compilation failure.gh-99941: Ensure that
asyncio.Protocol.data_received()
receives an immutablebytes
object (as documented), instead ofbytearray
.bpo-43984:
winreg.SetValueEx()
now leaves the target value untouched in the case of conversion errors. Previously,-1
would be written in case of such errors.bpo-34816:
hasattr(ctypes.windll, 'nonexistant')
now returnsFalse
instead of raisingOSError
.
macOS¶
Tools/Demos¶
bpo-45256: Fix a bug that caused an
AttributeError
to be raised inpython-gdb.py
whenpy-locals
is used without a frame.gh-100342: Add missing
NULL
check for possible allocation failure in*args
parsing in Argument Clinic.
C API¶
gh-99947: Raising SystemError on import will now have its cause be set to the original unexpected exception.
gh-99240: In argument parsing, after deallocating newly allocated memory, reset its pointer to NULL.
gh-98724: The
Py_CLEAR
,Py_SETREF
andPy_XSETREF
macros now only evaluate their arguments once. If an argument has side effects, these side effects are no longer duplicated. Patch by Victor Stinner.
Python 3.12.0 alpha 3¶
Release date: 2022-12-06
Security¶
gh-100001:
python -m http.server
no longer allows terminal control characters sent within a garbage request to be printed to the stderr server log.This is done by changing the
http.server
BaseHTTPRequestHandler
.log_message
method to replace control characters with a\xHH
hex escape before printing.gh-87604: Avoid publishing list of active per-interpreter audit hooks via the
gc
module
Core and Builtins¶
gh-99891: Fix a bug in the tokenizer that could cause infinite recursion when showing syntax warnings that happen in the first line of the source. Patch by Pablo Galindo
gh-91054: Add
PyCode_AddWatcher()
andPyCode_ClearWatcher()
APIs to register callbacks to receive notification on creation and destruction of code objects.gh-99729: Fix an issue that could cause frames to be visible to Python code as they are being torn down, possibly leading to memory corruption or hard crashes of the interpreter.
gh-99708: Fix bug where compiler crashes on an if expression with an empty body block.
gh-99578: Fix a reference bug in
_imp.create_builtin()
after the creation of the first sub-interpreter for modulesbuiltins
andsys
. Patch by Victor Stinner.gh-99581: Fixed a bug that was causing a buffer overflow if the tokenizer copies a line missing the newline character from a file that is as long as the available tokenizer buffer. Patch by Pablo galindo
gh-99553: Fix bug where an
ExceptionGroup
subclass can wrap aBaseException
.gh-99547: Add a function to os.path to check if a path is a junction: isjunction. Add similar functionality to pathlib.Path as is_junction.
gh-99370: Fix zip path for venv created from a non-installed python on POSIX platforms.
gh-99377: Add audit events for thread creation and clear operations.
gh-98686: Remove the
BINARY_OP_GENERIC
andCOMPARE_OP_GENERIC
"specializations".gh-99298: Remove the remaining error paths for attribute specializations, and refuse to specialize attribute accesses on types that haven't had
PyType_Ready()
called on them yet.gh-99127: Allow some features of
syslog
to the main interpreter only. Patch by Donghee Na.gh-91053: Optimizing interpreters and JIT compilers may need to invalidate internal metadata when functions are modified. This change adds the ability to provide a callback that will be invoked each time a function is created, modified, or destroyed.
gh-90994: Improve error messages when there's a syntax error with call arguments. The following three cases are covered: - No value is assigned to a named argument, eg
foo(a=)
. - A value is assigned to a star argument, egfoo(*args=[0])
. - A value is assigned to a double-star keyword argument, egfoo(**kwarg={'a': 0})
.bpo-45026: Optimize the
range
object iterator. It is now smaller, faster iteration of ranges containing large numbers. Smaller pickles, faster unpickling.bpo-31718: Raise
ValueError
instead ofSystemError
when methods of uninitializedio.IncrementalNewlineDecoder
objects are called. Patch by Oren Milman.bpo-38031: Fix a possible assertion failure in
io.FileIO
when the opener returns an invalid file descriptor.
Library¶
gh-100001: Also escape s in the http.server BaseHTTPRequestHandler.log_message so that it is technically possible to parse the line and reconstruct what the original data was. Without this a xHH is ambiguious as to if it is a hex replacement we put in or the characters r"x" came through in the original request line.
gh-99957: Add
frozen_default
parameter totyping.dataclass_transform()
.gh-79033: Fix
asyncio.Server.wait_closed()
to actually do what the docs promise -- wait for all existing connections to complete, after closing the server.gh-51524: Fix bug when calling trace.CoverageResults with valid infile.
gh-99645: Fix a bug in handling class cleanups in
unittest.TestCase
. NowaddClassCleanup()
uses separate lists for differentTestCase
subclasses, anddoClassCleanups()
only cleans up the particular class.gh-99508: Fix
TypeError
inLib/importlib/_bootstrap_external.py
while calling_imp.source_hash()
.gh-66285: Fix
asyncio
to not share event loop and signal wakeupfd in forked processes. Patch by Kumar Aditya.gh-97001: Release the GIL when calling termios APIs to avoid blocking threads.
gh-92647: Use final status of an enum to determine lookup or creation branch of functional API.
gh-99388: Add loop_factory parameter to
asyncio.run()
to allow specifying a custom event loop factory. Patch by Kumar Aditya.gh-99341: Fix
ast.increment_lineno()
to also coverast.TypeIgnore
when changing line numbers.gh-99382: Check the number of arguments in substitution in user generics containing a
TypeVarTuple
and one or moreTypeVar
.gh-99379: Fix substitution of
ParamSpec
followed byTypeVarTuple
in generic aliases.gh-99344: Fix substitution of
TypeVarTuple
andParamSpec
together in user generics.gh-99284: Remove
_use_broken_old_ctypes_structure_semantics_
old untested and undocumented hack fromctypes
.gh-99201: Fix
IndexError
when initializing the config variables on Windows ifHAVE_DYNAMIC_LOADING
is not set.gh-99240: Fix double-free bug in Argument Clinic
str_converter
by extracting memory clean up to a newpost_parsing
section.gh-64490: Fix refcount error when arguments are packed to tuple in Argument Clinic.
gh-99029:
pathlib.PurePath.relative_to()
now treats naked Windows drive paths as relative. This brings its behaviour in line with other parts of pathlib.gh-98253: The implementation of the typing module is now more resilient to reference leaks in binary extension modules.
Previously, a reference leak in a typed C API-based extension module could leak internals of the typing module, which could in turn introduce leaks in essentially any other package with typed function signatures. Although the typing package is not the original source of the problem, such non-local dependences exacerbate debugging of large-scale projects, and the implementation was therefore changed to reduce harm by providing better isolation.
gh-98458: Fix infinite loop in unittest when a self-referencing chained exception is raised
gh-93453:
asyncio.get_event_loop()
and many otherasyncio
functions likeasyncio.ensure_future()
,asyncio.shield()
orasyncio.gather()
, and also theget_event_loop()
method ofasyncio.BaseDefaultEventLoopPolicy
now raise aRuntimeError
if called when there is no running event loop and the current event loop was not set. Previously they implicitly created and set a new current event loop.DeprecationWarning
is no longer emitted if there is no running event loop but the current event loop was set.gh-97966: On
uname_result
, restored expectation that_fields
and_asdict
would include all six properties includingprocessor
.gh-98248: Provide informative error messages in
struct.pack()
when its integral arguments are not in range.gh-98108:
zipfile.Path
is now pickleable if its initialization parameters were pickleable (e.g. for file system paths).gh-98098: Created packages from zipfile and test_zipfile modules, separating
zipfile.Path
functionality.gh-82836: Fix
is_private
properties in theipaddress
module. Previously non-private networks (0.0.0.0/0) would returnTrue
from this method; now they correctly returnFalse
.gh-96828: Add an
OP_ENABLE_KTLS
option for enabling the use of the kernel TLS (kTLS). Patch by Illia Volochii.gh-88863: To avoid apparent memory leaks when
asyncio.open_connection()
raises, break reference cycles generated by local exception and future instances (which has exception instance as its member var). Patch by Dong Uk, Kang.gh-91078:
TarFile.next()
now returnsNone
when called on an empty tarfile.bpo-47220: Document the optional callback parameter of
WeakMethod
. Patch by Géry Ogam.bpo-44817: Ignore WinError 53 (ERROR_BAD_NETPATH), 65 (ERROR_NETWORK_ACCESS_DENIED) and 161 (ERROR_BAD_PATHNAME) when using ntpath.realpath().
bpo-41260: Rename the fmt parameter of the pure Python implementation of
datetime.date.strftime()
to format.bpo-15999: All built-in functions now accept arguments of any type instead of just
bool
andint
for boolean parameters.
Documentation¶
gh-99931: Use sphinxext-opengraph to generate OpenGraph metadata.
gh-89682: Reworded docstring of the default
__contains__
to clarify that it returns abool
.gh-88330: Improved the description of what a resource is in importlib.resources docs.
gh-92892: Document that calling variadic functions with ctypes requires special care on macOS/arm64 (and possibly other platforms).
bpo-41825: Restructured the documentation for the
os.wait*
family of functions, and improved the docs foros.waitid()
with more explanation of the possible argument constants.
Tests¶
gh-99892: Skip test_normalization() of test_unicodedata if it fails to download NormalizationTest.txt file from pythontest.net. Patch by Victor Stinner.
gh-99934: Correct test_marsh on (32 bit) x86: test_deterministic sets was failing.
gh-99741: We've implemented multi-phase init (PEP 489/630/687) for the internal (for testing) _xxsubinterpreters module.
gh-99659: Optional big memory tests in
test_sqlite3
now catch the correctsqlite.DataError
exception type in case of too large strings and/or blobs passed.gh-99593: Cover the Unicode C API with tests.
gh-96002: Add functional test for Argument Clinic.
Build¶
gh-99086: Fix
-Wimplicit-int
,-Wstrict-prototypes
, and-Wimplicit-function-declaration
compiler warnings in configure checks.gh-99337: Fix a compilation issue with GCC 12 on macOS.
gh-99289: Add a
COMPILEALL_OPTS
variable in Makefile to overridecompileall
options (default:-j0
) inmake install
. Also merged thecompileall
commands into a single command building .pyc files for the all optimization levels (0, 1, 2) at once. Patch by Victor Stinner.gh-98872: Fix a possible fd leak in
Programs/_freeze_module.c
introduced in Python 3.11.gh-88226: Always define
TARGET_*
labels inPython/ceval.c
, even ifUSE_COMPUTED_GOTOS
is disabled. This allows breakpoints to be set at those labels in (for instance)gdb
.
Windows¶
gh-99345: Use faster initialization functions to detect install location for Windows Store package
gh-98629: Fix initialization of
sys.version
andsys._git
on Windowsgh-99442: Fix handling in Lanceur Python pour Windows when
argv[0]
does not include a file extension.bpo-40882: Fix a memory leak in
multiprocessing.shared_memory.SharedMemory
on Windows.
macOS¶
Tools/Demos¶
gh-64490: Argument Clinic varargs bugfixes
Fix out-of-bounds error in
_PyArg_UnpackKeywordsWithVararg()
.Fix incorrect check which allowed more than one varargs in clinic.py.
Fix miscalculation of
noptargs
in generated code.Do not generate
noptargs
when there is a vararg argument and no optional argument.
C API¶
gh-98680:
PyBUF_*
constants were marked as part of Limited API of Python 3.11+. These were available in 3.11.0 withPy_LIMITED_API
defined for 3.11, and are necessary to use the buffer API.gh-99612: Fix
PyUnicode_DecodeUTF8Stateful()
for ASCII-only data:*consumed
was not set.gh-47146: The
structmember.h
header is deprecated. Its non-deprecated contents are now available just by includingPython.h
, with aPy_
prefix added if it was missing. (Deprecated contents areT_OBJECT
,T_NONE
, and no-op flags.) Patch by Petr Viktorin, based on earlier work by Alexander Belopolsky and Matthias Braun.
Python 3.12.0 alpha 2¶
Release date: 2022-11-14
Security¶
gh-98433: The IDNA codec decoder used on DNS hostnames by
socket
orasyncio
related name resolution functions no longer involves a quadratic algorithm. This prevents a potential CPU denial of service if an out-of-spec excessive length hostname involving bidirectional characters were decoded. Some protocols such asurllib
http3xx
redirects potentially allow for an attacker to supply such a name.Individual labels within an IDNA encoded DNS name will now raise an error early during IDNA decoding if they are longer than 1024 unicode characters given that each decoded DNS label must be 63 or fewer characters and the entire decoded DNS name is limited to 255. Only an application presenting a hostname or label consisting primarily of RFC 3454 section 3.1 "Nothing" characters to be removed would run into of this new limit. See also RFC 5894 section 6 and RFC 3491.
gh-98739: Update bundled libexpat to 2.5.0
Core and Builtins¶
gh-81057: The docs clearly say that
PyImport_Inittab
,PyImport_AppendInittab()
, andPyImport_ExtendInittab()
should not be used afterPy_Initialize()
has been called. We now enforce this for the two functions. Additionally, the runtime now uses an internal copy ofPyImport_Inittab
, to guard against modification.gh-99298: Fix an issue that could potentially cause incorrect error handling for some bytecode instructions.
gh-99254: The compiler now removes all unused constants from code objects (except the first one, which may be a docstring).
gh-99205: Fix an issue that prevented
PyThreadState
andPyInterpreterState
memory from being freed properly.gh-81057: The 18 global C variables holding the state of the allocators have been moved to
_PyRuntimeState
. This is a strictly internal change with no change in behavior.gh-99181: Fix failure in
except*
with unhashable exceptions.gh-99204: Fix calculation of
sys._base_executable
when inside a POSIX virtual environment using copies of the python binary when the base installation does not provide the executable name used by the venv. Calculation will fall back to alternative names ("python<MAJOR>", "python<MAJOR>.<MINOR>").gh-96055: Update
faulthandler
to emit an error message with the proper unexpected signal number. Patch by Donghee Na.gh-99153: Fix location of
SyntaxError
for atry
block with bothexcept
andexcept*
.gh-98686: Merge the adaptive opcode logic into each instruction's unquickened variant, and merge the logic in
EXTENDED_ARG_QUICK
intoEXTENDED_ARG
. With these changes, the quickening that happens at code object creation is now only responsible for initializing warmup counters and inserting superinstructions.gh-99103: Fix the error reporting positions of specialized traceback anchors when the source line contains Unicode characters.
gh-99139: Improve the error suggestion for
NameError
exceptions for instances. Now if aNameError
is raised in a method and the instance has an attribute that's exactly equal to the name in the exception, the suggestion will includeself.<NAME>
instead of the closest match in the method scope. Patch by Pablo Galindogh-98401: Octal escapes with value larger than
0o377
(ex:"\477"
), deprecated in Python 3.11, now produce aSyntaxWarning
, instead ofDeprecationWarning
. In a future Python version they will be eventually aSyntaxError
. Patch by Victor Stinner.gh-98401: A backslash-character pair that is not a valid escape sequence now generates a
SyntaxWarning
, instead ofDeprecationWarning
. For example,re.compile("\d+\.\d+")
now emits aSyntaxWarning
("\d"
is an invalid escape sequence), use raw strings for regular expression:re.compile(r"\d+\.\d+")
. In a future Python version,SyntaxError
will eventually be raised, instead ofSyntaxWarning
. Patch by Victor Stinner.gh-96793: Handle StopIteration and StopAsyncIteration raised in generator or coroutines in the bytecode, rather than in wrapping C code.
gh-98931: Improve the
SyntaxError
error message when the user typesimport x from y
instead offrom y import x
. Patch by Pablo Galindogh-98852: Fix subscription of type aliases containing bare generic types or types like
TypeVar
: for exampletuple[A, T][int]
andtuple[TypeVar, T][int]
, whereA
is a generic type, andT
is a type variable.gh-98925: Lower the recursion depth for marshal on WASI to support (in-development) wasmtime 2.0.
gh-98783: Fix multiple crashes in debug mode when
str
subclasses are used instead ofstr
itself.gh-98811: Use complete source locations to simplify detection of
__future__
imports which are not at the beginning of the file. Also corrects the offset in the exception raised in one case, which was off by one and impeded highlighting.gh-96793: Add specialization of
FOR_ITER
for generators. Saves multiple layers of dispatch and checking to get from theFOR_ITER
instruction in the caller to theRESUME
in the generator.gh-98586: Added the methods
PyObject_Vectorcall()
andPyObject_VectorcallMethod()
to the Limited API along with the auxiliary macro constantPY_VECTORCALL_ARGUMENTS_OFFSET
.The availability of these functions enables more efficient PEP 590 vector calls from binary extension modules that avoid argument boxing/unboxing overheads.
gh-99257: Fix an issue where member descriptors (such as those for
__slots__
) could behave incorrectly or crash instead of raising aTypeError
when accessed via an instance of an invalid type.gh-93143: Rather than changing
co_code
, the interpreter will now display aRuntimeWarning
and assignNone
to any fast locals that are left unbound after jumps ordel
statements executed while tracing.gh-96421: When calling into Python code from C code, through
PyEval_EvalFrameEx()
or a related C-API function, a shim frame in inserted into the call stack. This occurs in the_PyEval_EvalFrameDefault()
function. The extra frame should be invisible to all Python and most C extensions, but out-of-process profilers and debuggers need to be aware of it. These shim frames can be detected by checkingframe->owner == FRAME_OWNED_BY_CSTACK
.Extensions implementing their own interpreters using PEP 523 need to be aware of this shim frame and the changes to the semantics of
RETURN_VALUE
,YIELD_VALUE
, andRETURN_GENERATOR
, which now clear the frame.gh-98415: Fix detection of MAC addresses for
uuid
on certain OSs. Patch by Chaim Sandersgh-98686: Quicken all code objects, and specialize adaptive bytecode instructions more aggressively.
gh-92119: Print exception class name instead of its string representation when raising errors from
ctypes
calls.gh-91058:
ImportError
raised from failedfrom <module> import <name>
now include suggestions for the value of<name>
based on the available names in<module>
. Patch by Pablo Galindogh-96793: The
FOR_ITER
now leaves the iterator on the stack on termination of the loop. This is to assist specialization of loops for generators.gh-90716: Add _pylong.py module. It includes asymptotically faster algorithms that can be used for operations on integers with many digits. It is used by longobject.c to speed up some operations.
gh-95389: Expose
ETH_P_ALL
and some of the ETHERTYPE_* constants insocket
. Patch by Noam Cohen.gh-93696: Allow
pdb
to locate source for frozen modules in the standard library.
Library¶
gh-99418: Fix bug in
urllib.parse.urlparse()
that causes URL schemes that begin with a digit, a plus sign, or a minus sign to be parsed incorrectly.gh-94597: Deprecate
asyncio.AbstractChildWatcher
to be removed in Python 3.14. Patch by Kumar Aditya.gh-99305: Improve performance of
secrets.token_hex()
.gh-74044: Fixed bug where
inspect.signature()
reported incorrect arguments for decorated methods.gh-99275: Fix
SystemError
inctypes
when exception was not set during__initsubclass__
.gh-99277: Remove older version of
_SSLProtocolTransport.get_write_buffer_limits
inasyncio.sslproto
gh-99248: fix negative numbers failing in verify()
gh-99155: Fix
statistics.NormalDist
pickle with0
and1
protocols.gh-93464:
enum.auto()
is now correctly activated when combined with other assignment values. E.g.ONE = auto(), 'some text'
will now evaluate as(1, 'some text')
.gh-99134: Update the bundled copy of pip to version 22.3.1.
gh-92584: Remove the
distutils
package. It was deprecated in Python 3.10 by PEP 632 "Deprecate distutils module". For projects still usingdistutils
and cannot be updated to something else, thesetuptools
project can be installed: it still providesdistutils
. Patch by Victor Stinner.gh-98999: Now
_pyio
is consistent with_io
in raisingValueError
when executing methods over closed buffers.gh-83004: Clean up refleak on failed module initialisation in
_zoneinfo
gh-83004: Clean up refleaks on failed module initialisation in
_pickle
gh-83004: Clean up refleak on failed module initialisation in
_io
.gh-98897: Fix memory leak in
math.dist()
when both points don't have the same dimension. Patch by Kumar Aditya.gh-98878: Use the frame bound builtins when offering a name suggestion in
traceback
to prevent crashing when__builtins__
is not a dict.gh-98139: In
importlib._bootstrap
, enhance namespace package repr to<module 'x' (namespace) from ['path']>
.gh-90352: Fix
_SelectorDatagramTransport
to inherit fromDatagramTransport
inasyncio
. Patch by Kumar Aditya.gh-98793: Fix argument typechecks in
_overlapped.WSAConnect()
and_overlapped.Overlapped.WSASendTo()
functions.gh-98744: Prevent crashing in
traceback
when retrieving the byte-offset for some source files that contain certain unicode characters.gh-98740: Fix internal error in the
re
module which in very rare circumstances prevented compilation of a regular expression containing a conditional expression without the "else" branch.gh-98703: Fix
asyncio.StreamWriter.drain()
to callprotocol.connection_lost
callback only once on Windows.gh-98624: Add a mutex to unittest.mock.NonCallableMock to protect concurrent access to mock attributes.
gh-98658: The
array.array
class now supports subscripting, making it a generic type.gh-98284: Improved
TypeError
message for undefined abstract methods of aabc.ABC
instance. The names of the missing methods are surrounded by single-quotes to highlight them.gh-96151: Allow
BUILTINS
to be a valid field name for frozen dataclasses.gh-98086: Make sure
patch.dict()
can be applied on async functions.gh-72719: Remove modules
asyncore
andasynchat
, which were deprecated by PEP 594.gh-96192: Fix handling of
bytes
path-like objects inos.ismount()
.gh-94172:
ftplib
: Remove theFTP_TLS.ssl_version
class attribute: use the context parameter instead. Patch by Victor Stinnergh-94172: Remove the keyfile and certfile parameters from the
ftplib
,imaplib
,poplib
andsmtplib
modules, and the key_file, cert_file and check_hostname parameters from thehttp.client
module, all deprecated since Python 3.6. Use the context parameter (ssl_context inimaplib
) instead. Patch by Victor Stinner.gh-83638: Add the
autocommit
attribute tosqlite3.Connection
and the autocommit parameter tosqlite3.connect()
to control PEP 249-compliant transaction handling. Patch by Erlend E. Aasland.gh-92452: Fixed a race condition that could cause
sysconfig.get_config_var()
to incorrectly returnNone
in multi-threaded programs.gh-91803: Fix an error when using a method of objects mocked with
unittest.mock.create_autospec()
after it was sealed withunittest.mock.seal()
function.bpo-38523:
shutil.copytree()
now applies the ignore_dangling_symlinks argument recursively.bpo-40358: Add walk_up argument in
pathlib.PurePath.relative_to()
.bpo-36267: Fix IndexError in
argparse.ArgumentParser
when astore_true
action is given an explicit argument.
Documentation¶
gh-98832: Changes wording of docstring for
pathlib.Path.iterdir()
.gh-97966: Update uname docs to clarify the special nature of the platform attribute and to indicate when it became late-bound.
Tests¶
gh-98903: The Python test suite now fails with exit code 4 if no tests ran. It should help detecting typos in test names and test methods.
gh-98713: Fix a bug in the
typing
tests where a test relying on CPython-specific implementation details was not decorated with@cpython_only
and was not skipped on other implementations.gh-87390: Add tests for star-unpacking with PEP 646, and some other miscellaneous PEP 646 tests.
gh-96853: Added explicit coverage of
Py_Initialize
(and hencePy_InitializeEx
) back to the embedding tests (all other embedding tests migrated toPy_InitializeFromConfig
in Python 3.11)bpo-34272: Some C API tests were moved into the new Lib/test/test_capi/ directory.
Build¶
gh-99086: Fix
-Wimplicit-int
compiler warning in configure check forPTHREAD_SCOPE_SYSTEM
.gh-99016: Fix build with
PYTHON_FOR_REGEN=python3.8
.gh-97731: Specify the full path to the source location for
make docclean
(needed for cross-builds).gh-98949: Drop unused build dependency on
readelf
.gh-98989: Use
python3.11
, if available, for regeneration and freezing.gh-98831: Add new tooling, in
Tools/cases_generator
, to generate the interpreter switch statement from a list of opcode definitions. This only affects adding, modifying or removing instruction definitions. The instruction definitions now live inPython/bytecodes.c
, in the form of a custom DSL (under development). The tooling reads this file and writesPython/generated_cases.c.h
, which is then included byPython/ceval.c
to provide most of the cases of the main interpreter switch.gh-98817: Remove PCbuild/lib.pyproj: it's not used for anything, is only a minor convenience for Visual Studio users (who probably mostly don't even know about it), and it takes a lot of maintenance effort to keep updated.
gh-98776: Fix
make regen-test-levenshtein
for out-of-tree builds.gh-98707: Don't use vendored
libmpdec
headers if--with-system-libmpdec
is passed to configure. Don't use vendoredlibexpat
headers if--with-system-expat
is passed to configure.
Windows¶
gh-98689: Update Windows builds to zlib v1.2.13. v1.2.12 has CVE 2022-37434, but the vulnerable
inflateGetHeader
API is not used by Python.gh-98790: Assumes that a missing
DLLs
directory means that standard extension modules are in the executable's directory.gh-98745: Update
py.exe
launcher to install 3.11 by default and 3.12 on request.gh-98692: Fix the Lanceur Python pour Windows ignoring unrecognized shebang lines instead of treating them as local paths
gh-94328: Update Windows installer to use SQLite 3.39.4.
macOS¶
gh-94328: Update macOS installer to SQLite 3.39.4.
C API¶
gh-98724: The
Py_CLEAR
,Py_SETREF
andPy_XSETREF
macros now only evaluate their argument once. If the argument has side effects, these side effects are no longer duplicated. Patch by Victor Stinner.gh-98978: Fix use-after-free in
Py_SetPythonHome(NULL)
,Py_SetProgramName(NULL)
and_Py_SetProgramFullPath(NULL)
function calls. Issue reported by Benedikt Reinartz. Patch by Victor Stinner.gh-98410: Add
getbufferproc
andreleasebufferproc
to the stable API.gh-98610: Some configurable capabilities of sub-interpreters have changed. They always allow subprocesses (
subprocess
) now, whereas before subprocesses could be optionally disallowed for a sub-interpreter. Insteados.exec()
can now be disallowed. Disallowing daemon threads is now supported. Disallowing all threads is still allowed, but is never done by default. Note that the optional restrictions are only available through_Py_NewInterpreterFromConfig()
, which isn't a public API. They do not affect the main interpreter, norPy_NewInterpreter()
.gh-98608: A
_PyInterpreterConfig
has been added and_Py_NewInterpreter()
has been renamed to_Py_NewInterpreterFromConfig()
. The "isolated_subinterpreters" argument is now a granular config that captures the previous behavior. Note that this is all "private" API.gh-96853:
Py_InitializeEx
now correctly callsPyConfig_Clear
after initializing the interpreter (the omission didn't cause a memory leak only because none of the dynamically allocated config fields are populated by the wrapper function)gh-91248: Add
PyFrame_GetVar()
andPyFrame_GetVarString()
functions to get a frame variable by its name. Patch by Victor Stinner.
Python 3.12.0 alpha 1¶
Release date: 2022-10-25
Security¶
gh-97616: Fix multiplying a list by an integer (
list *= int
): detect the integer overflow when the new allocated length is close to the maximum size. Issue reported by Jordan Limor. Patch by Victor Stinner.gh-97514: On Linux the
multiprocessing
module returns to using filesystem backed unix domain sockets for communication with the forkserver process instead of the Linux abstract socket namespace. Only code that chooses to use the "forkserver" start method is affected.Abstract sockets have no permissions and could allow any user on the system in the same network namespace (often the whole system) to inject code into the multiprocessing forkserver process. This was a potential privilege escalation. Filesystem based socket permissions restrict this to the forkserver process user as was the default in Python 3.8 and earlier.
This prevents Linux CVE 2022-42919.
gh-87389:
http.server
: Fix an open redirection vulnerability in the HTTP server when an URI path starts with//
. Vulnerability discovered, and initial fix proposed, by Hamza Avvan.gh-79096: LWPCookieJar and MozillaCookieJar create files with file mode 600 instead of 644 (Microsoft Windows is not affected)
gh-92888: Fix
memoryview
use after free when accessing the backing buffer in certain cases.gh-68966: The deprecated mailcap module now refuses to inject unsafe text (filenames, MIME types, parameters) into shell commands. Instead of using such text, it will warn and act as if a match was not found (or for test commands, as if the test failed).
Core and Builtins¶
gh-98374: Suppress ImportError for invalid query for help() command. Patch by Donghee Na.
gh-98461: Fix source location in bytecode for list, set and dict comprehensions as well as generator expressions.
gh-98354: Added unicode check for
name
attribute ofspec
argument passed in_imp.create_builtin()
function.gh-98398: Fix source location of 'assert' bytecodes.
gh-98390: Fix location of sub-expressions of boolean expressions, by reducing their scope to that of the sub-expression.
gh-98254: Modules from the standard library are now potentially suggested as part of the error messages displayed by the interpreter when an
NameError
is raised to the top level. Patch by Pablo Galindogh-97997: Add running column offset to the tokenizer state to avoid calculating AST column information with pointer arithmetic.
gh-97973: Modify the tokenizer to return all necessary information the parser needs to set location information in the AST nodes, so that the parser does not have to calculate those doing pointer arithmetic.
gh-96078:
os.sched_yield()
now release the GIL while calling sched_yield(2). Patch by Donghee Na.gh-97912: The compiler now avoids quadratic behavior when finding which instructions should use the
LOAD_FAST_CHECK
opcode.gh-97002: Fix an issue where several frame objects could be backed by the same interpreter frame, possibly leading to corrupted memory and hard crashes of the interpreter.
gh-97943: Bugfix:
PyFunction_GetAnnotations()
should return a borrowed reference. It was returning a new reference.gh-97922: The Garbage Collector now runs only on the eval breaker mechanism of the Python bytecode evaluation loop instead on object allocations. The GC can also run when
PyErr_CheckSignals()
is called so C extensions that need to run for a long time without executing any Python code also have a chance to execute the GC periodically.gh-65961: When
__package__
is different than__spec__.parent
, raise aDeprecationWarning
instead ofImportWarning
.Also remove
importlib.util.set_package()
which was scheduled for removal.gh-97850: Long deprecated,
module_repr()
should now be completely eradicated.gh-86298: In cases where
warnings.warn_explicit()
consults the module's loader, anDeprecationWarning
is issued whenm.__loader__
differs fromm.__spec__.loader
.gh-97779: Ensure that all Python frame objects are backed by "complete" frames.
gh-91052: Add API for subscribing to modification events on selected dictionaries.
gh-97752: Fix possible data corruption or crashes when accessing the
f_back
member of newly-created generator or coroutine frames.gh-97591: Fixed a missing incref/decref pair in
Exception.__setstate__()
. Patch by Ofey Chan.gh-97670: Remove the
sys.getdxp()
function and theTools/scripts/analyze_dxp.py
script. DXP stands for "dynamic execution pairs". They were related toDYNAMIC_EXECUTION_PROFILE
andDXPAIRS
macros which have been removed in Python 3.11. Python can now be built with./configure --enable-pystats
to gather statistics on Python opcodes. Patch by Victor Stinner.gh-94526: Fix the Python path configuration used to initialized
sys.path
at Python startup. Paths are no longer encoded to UTF-8/strict to avoid encoding errors if it contains surrogate characters (bytes paths are decoded with the surrogateescape error handler). Patch by Victor Stinner.gh-96670: The parser now raises
SyntaxError
when parsing source code containing null bytes. Patch by Pablo Galindogh-96975: Fix a crash occurring when
PyEval_GetFrame()
is called while the topmost Python frame is in a partially-initialized state.gh-96848: Fix command line parsing: reject
-X int_max_str_digits
option with no value (invalid) when thePYTHONINTMAXSTRDIGITS
environment variable is set to a valid limit. Patch by Victor Stinner.gh-95921: Fix overly-broad source position information for chained comparisons used as branching conditions.
gh-96821: Fix undefined behaviour in
audioop.c
.gh-96821: Fix undefined behaviour in
_testcapimodule.c
.gh-95778: When
ValueError
is raised if an integer is larger than the limit, mention thesys.set_int_max_str_digits()
function in the error message. Patch by Victor Stinner.gh-96387: At Python exit, sometimes a thread holding the GIL can wait forever for a thread (usually a daemon thread) which requested to drop the GIL, whereas the thread already exited. To fix the race condition, the thread which requested the GIL drop now resets its request before exiting. Issue discovered and analyzed by Mingliang ZHAO. Patch by Victor Stinner.
gh-96864: Fix a possible assertion failure, fatal error, or
SystemError
if a line tracing event raises an exception while opcode tracing is enabled.gh-95778: The
PyLong_FromString
function was refactored to make it more maintainable and extensible.gh-96678: Fix undefined behaviour in C code of null pointer arithmetic.
gh-96754: Make sure that all frame objects created are created from valid interpreter frames. Prevents the possibility of invalid frames in backtraces and signal handlers.
gh-90997: Improve the performance of reading and writing inline bytecode caches on some platforms.
gh-96751: Remove dead code from
CALL_FUNCTION_EX
opcode.gh-90751:
memoryview
now supports half-floats. Patch by Donghee Na and Antoine Pitrou.gh-96678: Fix case of undefined behavior in ceval.c
gh-64373: Convert
_functools
to argument clinic.gh-96641: Do not expose
KeyWrapper
in_functools
.gh-96636: Ensure that tracing,
sys.setrace()
, is turned on immediately. In pre-release versions of 3.11, some tracing events might have been lost when turning on tracing in a__del__
method or interrupt.gh-96572: Fix use after free in trace refs build mode. Patch by Kumar Aditya.
gh-96611: When loading a file with invalid UTF-8 inside a multi-line string, a correct SyntaxError is emitted.
gh-96612: Make sure that incomplete frames do not show up in tracemalloc traces.
gh-90230: Fix compiler warnings and test failures when building with
--enable-pystats
.gh-96587: Correctly raise
SyntaxError
on exception groups (PEP 654) on python versions prior to 3.11gh-96569: Remove two cases of undefined behavior, by adding NULL checks.
gh-96582: Fix possible
NULL
pointer dereference in_PyThread_CurrentFrames
. Patch by Kumar Aditya.gh-91079: Separate Python recursion checking from C recursion checking which reduces the chance of C stack overflow and allows the recursion limit to be increased safely.
gh-93911: Fix an issue that could prevent
LOAD_ATTR
from specializing properly when accessing properties.gh-96348: Emit a DeprecationWarning when
throw()
,throw()
orathrow()
are called with more than one argument.gh-95196: Disable incorrect pickling of the C implemented classmethod descriptors.
gh-96364: Fix text signatures of
list.__getitem__
anddict.__getitem__
.gh-96352: Fix
AttributeError
missingname
andobj
attributes inobject.__getattribute__()
. Patch by Philip Georgi.gh-93554: Change the jump opcodes so that all conditional jumps are forward jumps. Backward jumps are converted by the assembler into a conditional forward jump whose target is the fallthrough block (and with a reversed condition), followed by an unconditional backward jump. For example:
POP_JUMP_IF_TRUE BACKWARD_TARGET
becomesPOP_JUMP_IF_FALSE NEXT_BLOCK; JUMP BACKWARD_TARGET
.All the directed conditional jump opcodes were removed:
POP_JUMP_FORWARD_IF_TRUE
,POP_JUMP_BACKWARD_IF_TRUE
,POP_JUMP_FORWARD_IF_FALSE
,POP_JUMP_BACKWARD_IF_FALSE
,POP_JUMP_FORWARD_IF_NONE
,POP_JUMP_BACKWARD_IF_NONE
,POP_JUMP_FORWARD_IF_NOT_NONE
,POP_JUMP_BACKWARD_IF_NOT_NONE
.The corresponding opcodes without direction are no longer pseudo-instructions, and they implement the forward conditional jumps.
gh-96268: Loading a file with invalid UTF-8 will now report the broken character at the correct location.
gh-96237: The internal field
_PyInterpreterFrame.f_func
is renamed to_PyInterpreterFrame.f_funcobj
and may be any object. Thef_globals
andf_builtin
fields may hold junk values.It is safest to treat the
_PyInterpreterFrame
struct as opaque.gh-96187: Fixed a bug that caused
_PyCode_GetExtra
to return garbage for negative indexes. Patch by Pablo Galindogh-96143: Add a new
-X perf
Python command line option as well assys.activate_stack_trampoline()
andsys.deactivate_stack_trampoline()
function in thesys
module that allows to set/unset the interpreter in a way that the Linuxperf
profiler can detect Python calls. The newsys.is_stack_trampoline_active()
function allows to query the state of the perf trampoline. Design by Pablo Galindo. Patch by Pablo Galindo and Christian Heimes with contributions from Gregory P. Smith [Google] and Mark Shannon.gh-96071: Fix a deadlock in
PyGILState_Ensure()
when allocating new thread state. Patch by Kumar Aditya.gh-96046:
PyType_Ready()
now initializesht_cached_keys
and performs additional checks to ensure that type objects are properly configured. This avoids crashes in 3rd party packages that don't use regular API to create new types.gh-96005: On WASI
ENOTCAPABLE
is now mapped toPermissionError
. Theerrno
modules exposes the new error number.getpath.py
now ignoresPermissionError
when it cannot open landmark filespybuilddir.txt
andpyenv.cfg
.gh-93678: Added test a harness for direct unit tests of the compiler's optimization stage. The
_testinternalcapi.optimize_cfg()
function runs the optimiser on a sequence of instructions. TheCfgOptimizationTestCase
class intest.support
has utilities for invoking the optimizer and checking the output.gh-95245: Reduces the size of a "simple" Python object from 8 to 6 words by moving the weakreflist pointer into the pre-header directly before the object's dict/values pointer.
gh-90997: Compile virtual
try
/except
blocks to handle exceptions raised duringclose()
orthrow()
calls through a suspended frame.gh-95977: Optimized calling
__get__()
with vectorcall. Patch by Kumar Aditya.gh-91210: Improve error message when a parameter without a default value follows one with a default value, and show the same message, even when the non-default/default sequence is preceded by positional-only parameters.
gh-95922: Fixed bug where the compiler's
eliminate_empty_basic_blocks
function ignores the last block of the code unit.gh-95818: Skip over incomplete frames in
PyThreadState_GetFrame()
.gh-95876: Fix format string in
_PyPegen_raise_error_known_location
that can lead to memory corruption on some 64bit systems. The function was building a tuple withi
(int) instead ofn
(Py_ssize_t) for Py_ssize_t arguments.gh-95605: Fix misleading contents of error message when converting an all-whitespace string to
float
.gh-95150: Update code object hashing and equality to consider all debugging and exception handling tables. This fixes an issue where certain non-identical code objects could be "deduplicated" during compilation.
gh-91146: Reduce allocation size of
list
fromstr.split()
andstr.rsplit()
. Patch by Donghee Na and Inada Naoki.gh-87092: Create a 'jump target label' abstraction in the compiler so that the compiler's codegen stage does not work directly with basic blocks. This prepares the code for changes to the underlying CFG generation mechanism.
gh-95355:
_PyPegen_Parser_New
now properly detects token memory allocation errors. Patch by Honglin Zhu.gh-90081: Run Python code in tracer/profiler function at full speed. Fixes slowdown in earlier versions of 3.11.
gh-95324: Emit a warning in debug mode if an object does not call
PyObject_GC_UnTrack()
before deallocation. Patch by Pablo Galindo.gh-95245: Merge managed dict and values pointer into a single tagged pointer to save one word in the pre-header.
gh-93678: Add cfg_builder struct and refactor the relevant code so that a cfg can be constructed without an instance of the compiler struct.
gh-95185: Prevented crashes in the AST constructor when compiling some absurdly long expressions like
"+0"*1000000
.RecursionError
is now raised instead. Patch by Pablo Galindogh-93351:
ast.AST
node positions are now validated when provided tocompile()
and other related functions. If invalid positions are detected, aValueError
will be raised.gh-94438: Fix an issue that caused extended opcode arguments and some conditional pops to be ignored when calculating valid jump targets for assignments to the
f_lineno
attribute of frame objects. In some cases, this could cause inconsistent internal state, resulting in a hard crash of the interpreter.gh-95060: Undocumented
PyCode_Addr2Location
function now properly returns whenaddrq
argument is less than zero.gh-95113: Replace all
EXTENDED_ARG_QUICK
instructions with basicEXTENDED_ARG
instructions in unquickened code. Consumers of non-adaptive bytecode should be able to handle extended arguments the same way they were handled in CPython 3.10 and older.gh-91409: Fix incorrect source location info caused by certain optimizations in the bytecode compiler.
gh-95023: Implement
os.setns()
andos.unshare()
for Linux. Patch by Noam Cohen.gh-94036: Fix incorrect source location info for some multi-line attribute accesses and method calls.
gh-94938: Fix error detection in some builtin functions when keyword argument name is an instance of a str subclass with overloaded
__eq__
and__hash__
. Previously it could cause SystemError or other undesired behavior.gh-94996:
ast.parse()
will no longer parse function definitions with positional-only params when passedfeature_version
less than(3, 8)
. Patch by Shantanu Jain.gh-94739: Allow jumping within, out of, and across exception handlers in the debugger.
gh-94949:
ast.parse()
will no longer parse parenthesized context managers when passedfeature_version
less than(3, 9)
. Patch by Shantanu Jain.gh-94947:
ast.parse()
will no longer parse assignment expressions when passedfeature_version
less than(3, 8)
. Patch by Shantanu Jain.gh-91256: Ensures the program name is known for help text during interpreter startup.
gh-94869: Fix the column offsets for some expressions in multi-line f-strings
ast
nodes. Patch by Pablo Galindo.gh-94893: Fix an issue where frame object manipulations could corrupt inline bytecode caches.
gh-94822: Fix an issue where lookups of metaclass descriptors may be ignored when an identically-named attribute also exists on the class itself.
gh-91153: Fix an issue where a
bytearray
item assignment could crash if it's resized by the new value's__index__()
method.gh-90699: Fix reference counting bug in
bool.__repr__()
. Patch by Kumar Aditya.gh-94694: Fix an issue that could cause code with multi-line method lookups to have misleading or incorrect column offset information. In some cases (when compiling a hand-built AST) this could have resulted in a hard crash of the interpreter.
gh-93252: Fix an issue that caused internal frames to outlive failed Python function calls, possibly resulting in memory leaks or hard interpreter crashes.
gh-94215: Fix an issue where exceptions raised by line-tracing events would cause frames to be left in an invalid state, possibly resulting in a hard crash of the interpreter.
gh-92228: Disable the compiler's inline-small-exit-blocks optimization for exit blocks that are associated with source code lines. This fixes a bug where the debugger cannot tell where an exception handler ends and the following code block begins.
gh-94485: Line number of a module's
RESUME
instruction is set to 0 as specified in PEP 626.gh-94438: Account for instructions that can push NULL to the stack when setting line number in a frame. Prevents some (unlikely) crashes.
gh-91719: Reload
opcode
when raisingunknown opcode error
in the interpreter main loop, for C compilers to generate dispatching code independently.gh-94329: Compile and run code with unpacking of extremely large sequences (1000s of elements). Such code failed to compile. It now compiles and runs correctly.
gh-94360: Fixed a tokenizer crash when reading encoded files with syntax errors from
stdin
with non utf-8 encoded text. Patch by Pablo Galindogh-88116: Fix an issue when reading line numbers from code objects if the encoded line numbers are close to
INT_MIN
. Patch by Pablo Galindogh-94262: Don't create frame objects for incomplete frames. Prevents the creation of generators and closures from being observable to Python and C extensions, restoring the behavior of 3.10 and earlier.
gh-94192: Fix error for dictionary literals with invalid expression as value.
gh-87995:
types.MappingProxyType
instances are now hashable if the underlying mapping is hashable.gh-93883: Revise the display strategy of traceback enhanced error locations. The indicators are only shown when the location doesn't span the whole line.
gh-94163: Add
BINARY_SLICE
andSTORE_SLICE
instructions for more efficient handling and better specialization of slicing operations, where the slice is explicit in the source code.gh-94021: Fix unreachable code warning in
Python/specialize.c
.gh-93911: Specialize
LOAD_ATTR
for objects with custom__getattribute__
.gh-93955: Improve performance of attribute lookups on objects with custom
__getattribute__
and__getattr__
. Patch by Ken Jin.gh-93911: Specialize
LOAD_ATTR
forproperty()
attributes.gh-93678: Refactor compiler optimisation code so that it no longer needs the
struct assembler
andstruct compiler
passed around. Instead, each function takes the CFG and other data that it actually needs. This will make it possible to test this code directly.gh-93841: When built with
-enable-pystats
,sys._stats_on()
,sys._stats_off()
,sys._stats_clear()
andsys._stats_dump()
functions have been added to enable gathering stats for parts of programs.gh-93516: Store offset of first traceable instruction in code object to avoid having to recompute it for each instruction when tracing.
gh-93516: Lazily create a table mapping bytecode offsets to line numbers to speed up calculation of line numbers when tracing.
gh-89828:
types.GenericAlias
no longer relays the__class__
attribute. For example,isinstance(list[int], type)
no longer returnsTrue
.gh-93678: Refactor the compiler to reduce boilerplate and repetition.
gh-93671: Fix some exponential backtrace case happening with deeply nested sequence patterns in match statements. Patch by Pablo Galindo
gh-93662: Make sure that the end column offsets are correct in multi-line method calls. Previously, the end column could precede the column offset.
gh-93461:
importlib.invalidate_caches()
now drops entries fromsys.path_importer_cache
with a relative path as name. This solves a caching issue when a process changes its current working directory.FileFinder
no longer inserts a dot in the path, e.g./egg/./spam
is now/egg/spam
.gh-93621: Change order of bytecode instructions emitted for
with
andasync with
to reduce the number of entries in the exception table.gh-93533: Reduce the size of the inline cache for
LOAD_METHOD
by 2 bytes.gh-93444: Removed redundant fields from the compiler's basicblock struct:
b_nofallthrough
,b_exit
,b_return
. They can be easily calculated from the opcode of the last instruction of the block.gh-93429:
LOAD_METHOD
instruction has been removed. It was merged back intoLOAD_ATTR
.gh-93418: Fixed an assert where an f-string has an equal sign '=' following an expression, but there's no trailing brace. For example, f"{i=".
gh-93382: Cache the result of
PyCode_GetCode()
function to restore the O(1) lookup of theco_code
attribute.gh-93359: Ensure that custom
ast
nodes without explicit end positions can be compiled. Patch by Pablo Galindo.gh-93356: Code for exception handlers is emitted at the end of the code unit's bytecode. This avoids one jump when no exception is raised.
gh-93354: Use exponential backoff for specialization counters in the interpreter. Can reduce the number of failed specializations significantly and avoid slowdown for those parts of a program that are not suitable for specialization.
gh-93283: Improve error message for invalid syntax of conversion character in f-string expressions.
gh-93345: Fix a crash in substitution of a
TypeVar
in nested generic alias afterTypeVarTuple
.gh-93223: When a bytecode instruction jumps to an unconditional jump instruction, the first instruction can often be optimized to target the unconditional jump's target directly. For tracing reasons, this would previously only occur if both instructions have the same line number. This also now occurs if the unconditional jump is artificial, i.e., if it has no associated line number.
gh-84694: The
--experimental-isolated-subinterpreters
configure option andEXPERIMENTAL_ISOLATED_SUBINTERPRETERS
macro have been removed.gh-91924: Fix
__lltrace__
debug feature if the stdout encoding is not UTF-8. Patch by Victor Stinner.gh-93040: Wraps unused parameters in
Objects/obmalloc.c
withPy_UNUSED
.gh-93143: Avoid
NULL
checks for uninitialized local variables by determining at compile time which variables must be initialized.gh-93061: Backward jumps after
async for
loops are no longer given dubious line numbers.gh-93065: Fix contextvars HAMT implementation to handle iteration over deep trees.
The bug was discovered and fixed by Eli Libman. See MagicStack/immutables#84 for more details.
gh-93012: Added the new function
PyType_FromMetaclass()
, which generalizes the existingPyType_FromModuleAndSpec()
using an additional metaclass argument. This is useful for language binding tools, where it can be used to intercept type-related operations like subclassing or static attribute access by specifying a metaclass with custom slots.Importantly,
PyType_FromMetaclass()
is available in the Limited API, which provides a path towards migrating more binding tools onto the Stable ABI.gh-93021: Fix the
__text_signature__
for__get__()
methods implemented in C. Patch by Jelle Zijlstra.gh-89914: The operand of the
YIELD_VALUE
instruction is set to the stack depth. This is done to help frame handling onyield
and may assist debuggers.gh-92955: Fix memory leak in code object's lines and positions iterators as they were not finalized at exit. Patch by Kumar Aditya.
gh-92930: Fixed a crash in
_pickle.c
from mutating collections during__reduce__
orpersistent_id
.gh-90690: The PRECALL instruction has been removed. It offered only a small advantage for specialization and is not needed in the vast majority of cases.
gh-92914: Always round the allocated size for lists up to the nearest even number.
gh-92858: Improve error message for some suites with syntax error before ':'
gh-90473: Decrease default recursion limit on WASI to address limited call stack size.
gh-92804: Fix memory leak in
memoryview
iterator as it was not finalized at exit. Patch by Kumar Aditya.gh-92777: Specialize
LOAD_METHOD
for objects with lazy dictionaries. Patch by Ken Jin.gh-92658: Add support for connecting and binding to Hyper-V sockets on Windows Hyper-V hosts and guests.
gh-92236: Remove spurious "LINE" event when starting a generator or coroutine, visible tracing functions implemented in C.
gh-91102:
_warnings.warn_explicit()
is ported to Argument Clinic.gh-92619: Make the compiler duplicate an exit block only if none of its instructions have a lineno (previously only the first instruction in the block was checked, leading to unnecessarily duplicated blocks).
gh-88750: The deprecated debug build only
PYTHONTHREADDEBUG
environment variable no longer does anything.gh-92261: Fix hang when trying to iterate over a
typing.Union
.gh-91432: Specialized the
FOR_ITER
opcode using the PEP 659 machinerygh-91399: Removed duplicate '{0, 0, 0, 0, 0, 0}' entry in 'Objects/unicodetype_db.h'.
gh-91578: Updates the error message for abstract class.
bpo-47091: Improve performance of repetition of
list
andtuple
by usingmemcpy
to copy data and performing the reference increments in one step.bpo-46142: Make
--help
output shorter by moving some info to the new--help-env
and--help-xoptions
command-line options. Also add--help-all
option to print complete usage.bpo-42316: Document some places where an assignment expression needs parentheses.
Library¶
gh-89237: Fix hang on Windows in
subprocess.wait_closed()
inasyncio
withProactorEventLoop
. Patch by Kumar Aditya.gh-97928:
tkinter.Text.count()
raises now an exception for options starting with "-" instead of silently ignoring them.gh-98393: The
os
module no longer accepts bytes-like paths, likebytearray
andmemoryview
types: only the exactbytes
type is accepted for bytes strings. Patch by Victor Stinner.gh-98363: Added itertools.batched() to batch data into lists of a given length with the last list possibly being shorter than the others.
gh-98331: Update the bundled copies of pip and setuptools to versions 22.3 and 65.5.0 respectively.
gh-98307: A
createSocket()
method was added toSysLogHandler
.gh-96035: Fix bug in
urllib.parse.urlparse()
that causes certain port numbers containing whitespace, underscores, plus and minus signs, or non-ASCII digits to be incorrectly accepted.gh-98257: Make
sys.setprofile()
andsys.settrace()
functions reentrant. They can no long fail with:RuntimeError("Cannot install a trace function while another trace function is being installed")
. Patch by Victor Stinner.gh-98251: Allow
venv
to pass alongPYTHON*
variables toensurepip
andpip
when they do not impact path resolutiongh-94597: Deprecated
asyncio.AbstractEventLoopPolicy.get_child_watcher()
andasyncio.AbstractEventLoopPolicy.set_child_watcher()
methods to be removed in Python 3.14. Patch by Kumar Aditya.gh-98178: On macOS, fix a crash in
syslog.syslog()
in multi-threaded applications. On macOS, the libcsyslog()
function is not thread-safe, sosyslog.syslog()
no longer releases the GIL to call it. Patch by Victor Stinner.gh-44098: Release the GIL when creating
mmap.mmap
objects on Unix.gh-87730: Wrap network errors consistently in urllib FTP support, so the test suite doesn't fail when a network is available but the public internet is not reachable.
gh-94597: The child watcher classes
MultiLoopChildWatcher
,FastChildWatcher
andSafeChildWatcher
are deprecated and will be removed in Python 3.14. Patch by Kumar Aditya.gh-98023: Change default child watcher to
PidfdChildWatcher
on Linux systems which supports it. Patch by Kumar Aditya.gh-90985: Earlier in 3.11 we deprecated
asyncio.Task.cancel("message")
. We realized we were too harsh, and have undeprecated it.gh-65961: Do not rely solely on
__cached__
on modules; code will also support__spec__.cached
.gh-97646: Replace deprecated
application/javascript
withtext/javascript
inmimetypes
. See RFC 9239. Patch by Noam Cohen.gh-97930: Apply changes from importlib_resources 5.8 and 5.9:
Traversable.joinpath
provides a concrete implementation.as_file
now supports directories of resources.gh-97850: Remove deprecated
importlib.util.set_loader()
andimportlib.util.module_for_loader()
fromimportlib.util
.gh-97837: Change deprecate warning message in
unittest
fromIt is deprecated to return a value!=None
to
It is deprecated to return a value that is not None from a test case
gh-97825: Fixes
AttributeError
whensubprocess.check_output()
is used with argumentinput=None
and either of the arguments encoding or errors are used.gh-97008:
NameError
andAttributeError
spelling suggestions provided since gh-82711 are now also emitted by the pure Pythontraceback
module. Tests for those suggestions now exercise both implementations to ensure they are equivalent. Patch by Carl Friedrich Bolz-Tereick and Łukasz Langa.gh-97799:
dataclass
now usesinspect.get_annotations()
to examine the annotations on class objects.gh-97781: Removed deprecated interfaces in
importlib.metadata
(entry points accessed as dictionary, implicit dictionary construction of sequence ofEntryPoint
objects, mutablility ofEntryPoints
result, access of entry point by index).entry_points
now has a simpler, more straightforward API (returningEntryPoints
).gh-96827: Avoid spurious tracebacks from
asyncio
when default executor cleanup is delayed until after the event loop is closed (e.g. as the result of a keyboard interrupt).gh-95534:
gzip.GzipFile.read()
reads 10% faster.gh-97592: Avoid a crash in the C version of
asyncio.Future.remove_done_callback()
when an evil argument is passed.gh-97545: Make Semaphore run faster.
gh-73588: Fix generation of the default name of
tkinter.Checkbutton
. Previously, checkbuttons in different parent widgets could have the same short name and share the same state if arguments "name" and "variable" are not specified. Now they are globally unique.gh-96865: fix Flag to use boundary CONFORM
This restores previous Flag behavior of allowing flags with non-sequential values to be combined; e.g.
class Skip(Flag): TWO = 2 EIGHT = 8
Skip.TWO | Skip.EIGHT -> <Skip.TWO|EIGHT: 10>
gh-97005: Update bundled libexpat to 2.4.9
gh-85760: Fix race condition in
asyncio
whereprocess_exited()
called before thepipe_data_received()
leading to inconsistent output. Patch by Kumar Aditya.gh-96704: Pass the correct
contextvars.Context
when aasyncio
exception handler is called on behalf of a task or callback handle. This adds a newTask
method,get_context
, and also a newHandle
method with the same name. If this method is not found on a task object (perhaps because it is a third-party library that does not yet provide this method), the context prevailing at the time the exception handler is called is used.gh-96819: Fixed check in
multiprocessing.resource_tracker
that guarantees that the length of a write to a pipe is not greater thanPIPE_BUF
.gh-95865: Reduce
urllib.parse.quote_from_bytes()
memory use on large values.Contributed by Dennis Sweeney.
gh-96741: Corrected type annotation for dataclass attribute
pstats.FunctionProfile.ncalls
to bestr
.gh-96734: Update
unicodedata
database to Unicode 15.0.0.gh-96735: Fix undefined behaviour in
struct.unpack()
.gh-46412: Improve performance of
bool(db)
for large ndb/gdb databases. Previously this would calllen(db)
which would iterate over all keys -- the answer (empty or not) is known after the first key.gh-96652: Fix the faulthandler implementation of
faulthandler.register(signal, chain=True)
if thesigaction()
function is not available: don't call the previous signal handler if it's NULL. Patch by Victor Stinner.gh-68163: Correct conversion of
numbers.Rational
's tofloat
.gh-96538: Speed up
bisect.bisect()
functions by taking advantage of type-stability.gh-96465: Fraction hashes are now cached.
gh-96079: In
typing
, fix missing fieldname
and incorrect__module__
in _AnnotatedAlias.gh-96415: Remove
types._cell_factory
from module namespace.gh-95987: Fix
repr
ofAny
subclasses.gh-96388: Work around missing socket functions in
socket
's__repr__
.gh-96385: Fix
TypeVarTuple.__typing_prepare_subst__
.TypeError
was not raised when using more than oneTypeVarTuple
, like[*T, *V]
in type alias substitutions.gh-96142: Add
match_args
,kw_only
,slots
, andweakref_slot
to_DataclassParams
.gh-96073: In
inspect
, fix overeager replacement of "typing.
" in formatting annotations.gh-89258: Added a
getChildren()
method tologging.Logger
, to get the immediate child loggers of a logger.gh-96346: Use double caching for compiled RE patterns.
gh-96349: Fixed a minor performance regression in
threading.Event.__init__()
gh-90467: Fix
asyncio.streams.StreamReaderProtocol
to keep a strong reference to the created task, so that it's not garbage collectedgh-96172: Fix a bug in
unicodedata
:east_asian_width
used to return the wrong value for unassigned characters; and for yet unassigned, but reserved characters.gh-96159: Fix a performance regression in logging TimedRotatingFileHandler. Only check for special files when the rollover time has passed.
gh-96175: Fix unused
localName
parameter in theAttr
class inxml.dom.minidom
.gh-96145: Add AttrDict to JSON module for use with object_hook.
gh-96052: Fix handling compiler warnings (SyntaxWarning and DeprecationWarning) in
codeop.compile_command()
when checking for incomplete input. Previously it emitted warnings and raised a SyntaxError. Now it always returnsNone
for incomplete input without emitting any warnings.gh-96125: Fix incorrect condition that causes
sys.thread_info.name
to be wrong on pthread platforms.gh-96019: Fix a bug in the
makeunicodedata.py
script leading to about 13 KiB of space saving in theunicodedata
module, specifically the character decomposition data.gh-95463: Remove an incompatible change from bpo-28080 that caused a regression that ignored the utf8 in
ZipInfo.flag_bits
. Patch by Pablo Galindo.gh-69142: Add
%:z
strftime format code (generates tzoffset with colons as separator), see strftime() and strptime() Behavior.gh-95899: Fix
asyncio.Runner
to callasyncio.set_event_loop()
only once to avoid callingattach_loop()
multiple times on child watchers. Patch by Kumar Aditya.gh-95736: Fix
unittest.IsolatedAsyncioTestCase
to set event loop before calling setup functions. Patch by Kumar Aditya.gh-95865: Speed up
urllib.parse.quote_from_bytes()
by replacing a list comprehension withmap()
.gh-95861: Add support for computing Spearman's correlation coefficient to the existing statistics.correlation() function.
gh-95804: Fix
logging
shutdown handler so it respectsMemoryHandler.flushOnClose
.gh-95704: When a task catches
asyncio.CancelledError
and raises some other error, the other error should generally not silently be suppressed.gh-95149: The
HTTPStatus
enum offers a couple of properties to indicate the HTTP status category e.g.HTTPStatus.OK.is_success
.gh-95609: Update bundled pip to 22.2.2.
gh-95289: Fix
asyncio.TaskGroup
to propagate exception whenasyncio.CancelledError
was replaced with another exception by a context manager. Patch by Kumar Aditya and Guido van Rossum.gh-94909: Fix incorrect joining of relative Windows paths with drives in
pathlib.PurePath
initializer.gh-95385: Faster
json.dumps()
when sorting of keys is not requested (default).gh-83901: Improve
Signature.bind
error message for missing keyword-only arguments.gh-95339: Update bundled pip to 22.2.1.
gh-95045: Fix GC crash when deallocating
_lsprof.Profiler
by untracking it before calling any callbacks. Patch by Kumar Aditya.gh-95231: Fail gracefully if
EPERM
orENOSYS
is raised when loadingcrypt
methods. This may happen when trying to loadMD5
on a Linux kernel with FIPS enabled.gh-95097: Fix
asyncio.run()
forasyncio.Task
implementations withoutuncancel()
method. Patch by Kumar Aditya.gh-95087: Fix IndexError in parsing invalid date in the
email
module.gh-95199: Upgrade bundled setuptools to 63.2.0.
gh-95194: Upgrade bundled pip to 22.2.
gh-93899: Fix check for existence of
os.EFD_CLOEXEC
,os.EFD_NONBLOCK
andos.EFD_SEMAPHORE
flags on older kernel versions where these flags are not present. Patch by Kumar Aditya.gh-95166: Fix
concurrent.futures.Executor.map()
to cancel the currently waiting on future on an error - e.g. TimeoutError or KeyboardInterrupt.gh-95132: Fix a
sqlite3
regression where*args
and**kwds
were incorrectly relayed fromconnect()
to theConnection
factory. The regression was introduced in 3.11a1 with PR 24421 (gh-85128). Patch by Erlend E. Aasland.gh-93157: Fix
fileinput
module didn't supporterrors
option wheninplace
is true.gh-91212: Fixed flickering of the turtle window when the tracer is turned off. Patch by Shin-myoung-serp.
gh-95077: Add deprecation warning for enum
member.member
access (e.g.Color.RED.BLUE
). RemoveEnumMeta.__getattr__
.gh-95109: Ensure that timeouts scheduled with
asyncio.Timeout
that have already expired are delivered promptly.gh-95105:
wsgiref.types.InputStream.__iter__()
should returnIterator[bytes]
, notIterable[bytes]
. Patch by Shantanu Jain.gh-95066: Replaced assert with exception in
ast.parse()
, whenfeature_version
has an invalid major version. Patch by Shantanu Jain.gh-77617: Add
sqlite3
command-line interface. Patch by Erlend Aasland.gh-95005: Replace _PyAccu with _PyUnicodeWriter in JSON encoder and StringIO and remove the _PyAccu implementation.
gh-90085: Remove
-c/--clock
and-t/--time
CLI options oftimeit
. The options had been deprecated since Python 3.3 and the functionality was removed in Python 3.7. Patch by Shantanu Jain.gh-94857: Fix refleak in
_io.TextIOWrapper.reconfigure
. Patch by Kumar Aditya.gh-94821: Fix binding of unix socket to empty address on Linux to use an available address from the abstract namespace, instead of "0".
gh-94736: Fix crash when deallocating an instance of a subclass of
_multiprocessing.SemLock
. Patch by Kumar Aditya.gh-81620: Add random.binomialvariate().
gh-74116: Allow
asyncio.StreamWriter.drain()
to be awaited concurrently by multiple tasks. Patch by Kumar Aditya.gh-87822: When called with
capture_locals=True
, thetraceback
module functions swallow exceptions raised from calls torepr()
on local variables of frames. This is in order to prioritize the original exception over rendering errors. An indication of the failure is printed in place of the missing value. (Patch by Simon-Martin Schroeder).gh-88050: Fix
asyncio
subprocess transport to kill process cleanly when process is blocked and avoidRuntimeError
when loop is closed. Patch by Kumar Aditya.gh-94637:
SSLContext.set_default_verify_paths()
now releases the GIL aroundSSL_CTX_set_default_verify_paths
call. The function call performs I/O and CPU intensive work.gh-94309: Deprecate aliases
typing.Hashable
andtyping.Sized
gh-92546: An undocumented
python -m pprint
benchmark is moved intopprint
suite of pyperformance. Patch by Oleg Iarygin.gh-94607: Fix subclassing complex generics with type variables in
typing
. Previously an error message sayingSome type variables ... are not listed in Generic[...]
was shown.typing
no longer populates__parameters__
with the