Changelog¶
Python 3.9.21 final¶
Release date: 2024-12-03
Tests¶
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.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-100454: Fix SSL tests CI for OpenSSL 3.1+
Security¶
Library¶
gh-124651: Properly quote template strings in
venv
activation scripts.gh-103848: Add checks to ensure that
[
bracketed]
hosts found byurllib.parse.urlsplit()
are of IPv6 or IPvFuture format.
Documentation¶
gh-95588: Clarified the conflicting advice given in the
ast
documentation aboutast.literal_eval()
being "safe" for use on untrusted input while at the same time warning that it can crash the process. The latter statement is true and is deemed unfixable without a large amount of work unsuitable for a bugfix. So we keep the warning and no longer claim thatliteral_eval
is safe.
Python 3.9.20 final¶
Release date: 2024-09-06
Windows¶
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-117187: Fix XML tests for vanilla Expat <2.6.0.
Security¶
gh-123678: Upgrade libexpat to 2.6.3
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>
gh-121285: Remove backtracking from tarfile header parsing for
hdrcharset
, PAX, and GNU sparse headers.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-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.gh-116741: Update bundled libexpat to 2.6.2
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-123067: Fix quadratic complexity in parsing
"
-quoted cookie values with backslashes byhttp.cookies
.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-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-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-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.
Core and Builtins¶
gh-112275: A deadlock involving
pystate.c
'sHEAD_LOCK
inposixmodule.c
at fork is now fixed. Patch by ChuBoning based on previous Python 3.12 fix by Victor Stinner.
Python 3.9.19 final¶
Release date: 2024-03-19
Security¶
Core and Builtins¶
gh-102388: Fix a bug where
iso2022_jp_3
andiso2022_jp_2004
codecs read out of bounds
Library¶
gh-115197:
urllib.request
no longer resolves the hostname before checking it against the system's proxy bypass list on macOS and Windows.gh-115133: Fix tests for
XMLPullParser
with Expat 2.6.0.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-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-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-91133: Fix a bug in
tempfile.TemporaryDirectory
cleanup, which now no longer dereferences symlinks when working around file system permission errors.
Documentation¶
gh-115399: Document CVE-2023-52425 of Expat <2.6.0 under "XML vulnerabilities".
Windows¶
Tools/Demos¶
gh-109991: Update GitHub CI workflows to use OpenSSL 3.0.11 and multissltests to use 1.1.1w and 3.0.11.
Python 3.9.18 final¶
Release date: 2023-08-24
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.
Library¶
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
.
Tools/Demos¶
gh-107565: Update multissltests and GitHub CI workflows to use OpenSSL 1.1.1v, 3.0.10, and 3.1.2.
C API¶
gh-99612: Fix
PyUnicode_DecodeUTF8Stateful()
for ASCII-only data:*consumed
was not set.
Python 3.9.17 final¶
Release date: 2023-06-06
Security¶
gh-103142: The version of OpenSSL used in our binary builds has been upgraded to 1.1.1u to address several CVEs.
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-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.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-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-102126: Fix deadlock at shutdown when clearing thread states if any finalizer tries to acquire the runtime head lock. Patch by Kumar Aditya.
gh-100892: Fix race while iterating over thread states in clearing
threading.local
. Patch by Kumar Aditya.
Library¶
gh-103935: Use
io.open_code()
for files to be executed instead of rawopen()
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-101997: Upgrade pip wheel bundled with ensurepip (pip 23.0.1)
Windows¶
gh-100180: Update Windows installer to OpenSSL 1.1.1s
macOS¶
gh-103142: Update macOS installer to use OpenSSL 1.1.1u.
Python 3.9.16 final¶
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
modulegh-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.gh-98739: Update bundled libexpat to 2.5.0
gh-98517: Port XKCP's fix for the buffer overflows in SHA-3 (CVE-2022-37454).
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-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).
Python 3.9.15 final¶
Release date: 2022-10-11
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-97612: Fix a shell code injection vulnerability in the
get-remote-certificate.py
example script. The script no longer uses a shell to runopenssl
commands. Issue reported and initial fix by Caleb Shortt. Patch by Victor Stinner.
Core and Builtins¶
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-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.
Library¶
gh-97005: Update bundled libexpat to 2.4.9
Windows¶
macOS¶
gh-97897: The macOS 13 SDK includes support for the
mkfifoat
andmknodat
system calls. Using thedir_fd
option with eitheros.mkfifo()
oros.mknod()
could result in a segfault if cpython is built with the macOS 13 SDK but run on an earlier version of macOS. Prevent this by adding runtime support for detection of these system calls ("weaklinking") as is done for other newer syscalls on macOS.
Python 3.9.14 final¶
Release date: 2022-09-06
Security¶
gh-95778: Converting between
int
andstr
in bases other than 2 (binary), 4, 8 (octal), 16 (hexadecimal), or 32 such as base 10 (decimal) now raises aValueError
if the number of digits in string form is above a limit to avoid potential denial of service attacks due to the algorithmic complexity. This is a mitigation for CVE-2020-10735.This new limit can be configured or disabled by environment variable, command line flag, or
sys
APIs. See the integer string conversion length limitation documentation. The default limit is 4300 digits in string form.Patch by Gregory P. Smith [Google] and Christian Heimes [Red Hat] with feedback from Victor Stinner, Thomas Wouters, Steve Dower, Ned Deily, and Mark Dickinson.
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.
Core and Builtins¶
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.
Library¶
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-91810: Suppress writing an XML declaration in open files in
ElementTree.write()
withencoding='unicode'
andxml_declaration=None
.bpo-45393: Fix the formatting for
await x
andnot x
in the operator precedence table when using thehelp()
system.bpo-46197: Fix
ensurepip
environment isolation for subprocess runningpip
.
Tests¶
gh-95280: Fix problem with
test_ssl
test_get_ciphers
on systems that require perfect forward secrecy (PFS) ciphers.gh-94208:
test_ssl
is now checking for supported TLS version and protocols in more tests.bpo-47016: Create a GitHub Actions workflow for verifying bundled pip and setuptools. Patch by Illia Volochii and Adam Turner.
Python 3.9.13 final¶
Release date: 2022-05-17
Core and Builtins¶
gh-92311: Fixed a bug where setting
frame.f_lineno
to jump over a list comprehension could misbehave or crash.gh-92112: Fix crash triggered by an evil custom
mro()
on a metaclass.gh-92036: Fix a crash in subinterpreters related to the garbage collector. When a subinterpreter is deleted, untrack all objects tracked by its GC. To prevent a crash in deallocator functions expecting objects to be tracked by the GC, leak a strong reference to these objects on purpose, so they are never deleted and their deallocator functions are not called. Patch by Victor Stinner.
gh-91421: Fix a potential integer overflow in _Py_DecodeUTF8Ex.
bpo-46775: Some Windows system error codes(>= 10000) are now mapped into the correct errno and may now raise a subclass of
OSError
. Patch by Dong-hee Na.bpo-46962: Classes and functions that unconditionally declared their docstrings ignoring the
--without-doc-strings
compilation flag no longer do so.The classes affected are
pickle.PickleBuffer
,testcapi.RecursingInfinitelyError
, andtypes.GenericAlias
.The functions affected are 24 methods in
ctypes
.Patch by Oleg Iarygin.
bpo-36819: Fix crashes in built-in encoders with error handlers that return position less or equal than the starting position of non-encodable characters.
Library¶
gh-91581:
utcfromtimestamp()
no longer attempts to resolvefold
in the pure Python implementation, since the fold is never 1 in UTC. In addition to being slightly faster in the common case, this also prevents some errors when the timestamp is close todatetime.min
. Patch by Paul Ganssle.gh-92530: Fix an issue that occurred after interrupting
threading.Condition.notify()
.gh-92049: Forbid pickling constants
re._constants.SUCCESS
etc. Previously, pickling did not fail, but the result could not be unpickled.bpo-47029: Always close the read end of the pipe used by
multiprocessing.Queue
after the last write of buffered data to the write end of the pipe to avoidBrokenPipeError
at garbage collection and atmultiprocessing.Queue.close()
calls. Patch by Géry Ogam.gh-91910: Add missing f prefix to f-strings in error messages from the
multiprocessing
andasyncio
modules.gh-91810:
ElementTree
methodwrite()
and functiontostring()
now use the text file's encoding ("UTF-8" if not available) instead of locale encoding in XML declaration whenencoding="unicode"
is specified.gh-91832: Add
required
attribute toargparse.Action
repr output.gh-91734: Fix OSS audio support on Solaris.
gh-91700: Compilation of regular expression containing a conditional expression
(?(group)...)
now raises an appropriatere.error
if the group number refers to not defined group. Previously an internal RuntimeError was raised.gh-91676: Fix
unittest.IsolatedAsyncioTestCase
to shutdown the per test event loop executor before returning from itsrun
method so that a not yet stopped or garbage collected executor state does not persist beyond the test.gh-90568: Parsing
\N
escapes of Unicode Named Character Sequences in aregular expression
raises nowre.error
instead ofTypeError
.gh-91595: Fix the comparison of character and integer inside
Tools.gdb.libpython.write_repr()
. Patch by Yu Liu.gh-90622: Worker processes for
concurrent.futures.ProcessPoolExecutor
are no longer spawned on demand (a feature added in 3.9) when the multiprocessing context start method is"fork"
as that can lead to deadlocks in the child processes due to a fork happening while threads are running.gh-91575: Update case-insensitive matching in the
re
module to the latest Unicode version.gh-91581: Remove an unhandled error case in the C implementation of calls to
datetime.fromtimestamp
with no time zone (i.e. getting a local time from an epoch timestamp). This should have no user-facing effect other than giving a possibly more accurate error message when called with timestamps that fall on 10000-01-01 in the local time. Patch by Paul Ganssle.bpo-34480: Fix a bug where
_markupbase
raised anUnboundLocalError
when an invalid keyword was found in marked section. Patch by Marek Suscak.bpo-27929: Fix
asyncio.loop.sock_connect()
to only resolve names forsocket.AF_INET
orsocket.AF_INET6
families. Resolution may not make sense for other families, likesocket.AF_BLUETOOTH
andsocket.AF_UNIX
.bpo-43323: Fix errors in the
email
module if the charset itself contains undecodable/unencodable characters.bpo-46787: Fix
concurrent.futures.ProcessPoolExecutor
exception memory leakbpo-46415: Fix ipaddress.ip_{address,interface,network} raising TypeError instead of ValueError if given invalid tuple as address parameter.
bpo-44911:
IsolatedAsyncioTestCase
will no longer throw an exception while cancelling leaked tasks. Patch by Bar Harel.bpo-44493: Add missing terminated NUL in sockaddr_un's length
This was potentially observable when using non-abstract AF_UNIX datagram sockets to processes written in another programming language.
bpo-42627: Fix incorrect parsing of Windows registry proxy settings
bpo-36073: Raise
ProgrammingError
instead of segfaulting on recursive usage of cursors insqlite3
converters. Patch by Sergey Fedoseev.
Documentation¶
gh-91888: Add a new
gh
role to the documentation to link to GitHub issues.gh-91783: Document security issues concerning the use of the function
shutil.unpack_archive()
gh-91547: Remove "Undocumented modules" page.
bpo-44347: Clarify the meaning of dirs_exist_ok, a kwarg of
shutil.copytree()
.bpo-38668: Update the introduction to documentation for
os.path
to remove warnings that became irrelevant after the implementations of PEP 383 and PEP 529.bpo-47138: Pin Jinja to a version compatible with Sphinx version 2.4.4.
bpo-46962: All docstrings in code snippets are now wrapped into
PyDoc_STR()
to follow the guideline of PEP 7's Documentation Strings paragraph. Patch by Oleg Iarygin.bpo-26792: Improve the docstrings of
runpy.run_module()
andrunpy.run_path()
. Original patch by Andrew Brezovsky.bpo-45790: Adjust inaccurate phrasing in Tutoriel : définir des types dans des extensions about the
ob_base
field and the macros used to access its contents.bpo-42340: Document that in some circumstances
KeyboardInterrupt
may cause the code to enter an inconsistent state. Provided a sample workaround to avoid it if needed.bpo-41233: Link the errnos referenced in
Doc/library/exceptions.rst
to their respective section inDoc/library/errno.rst
, and vice versa. Previously this was only done for EINTR and InterruptedError. Patch by Yan "yyyyyyyan" Orestes.bpo-38056: Overhaul the Gestionnaires d'erreurs documentation in
codecs
.bpo-13553: Document tkinter.Tk args.
Tests¶
gh-91607: Fix
test_concurrent_futures
to test the correct multiprocessing start method context in several cases where the test logic mixed this up.bpo-47205: Skip test for
sched_getaffinity()
andsched_setaffinity()
error case on FreeBSD.bpo-29890: Add tests for
ipaddress.IPv4Interface
andipaddress.IPv6Interface
construction with tuple arguments. Original patch and tests by louisom.
Build¶
bpo-47103: Windows
PGInstrument
builds now copy a required DLL into the output directory, making it easier to run the profile stage of a PGO build.
Windows¶
Tools/Demos¶
gh-91583: Fix regression in the code generated by Argument Clinic for functions with the
defining_class
parameter.
Python 3.9.12 final¶
Release date: 2022-03-23
Core and Builtins¶
bpo-46968: Check for the existence of the "sys/auxv.h" header in
faulthandler
to avoid compilation problems in systems where this header doesn't exist. Patch by Pablo Galindo
Library¶
bpo-47101:
hashlib.algorithms_available
now lists only algorithms that are provided by activated crypto providers on OpenSSL 3.0. Legacy algorithms are not listed unless the legacy provider has been loaded into the default OSSL context.bpo-23691: Protect the
re.finditer()
iterator from re-entering.bpo-42369: Fix thread safety of
zipfile._SharedFile.tell()
to avoid a "zipfile.BadZipFile: Bad CRC-32 for file" exception when reading aZipFile
from multiple threads.bpo-38256: Fix
binascii.crc32()
when it is compiled to use zlib'c crc32 to work properly on inputs 4+GiB in length instead of returning the wrong result. The workaround prior to this was to always feed the function data in increments smaller than 4GiB or to just call the zlib module function.bpo-39394: A warning about inline flags not at the start of the regular expression now contains the position of the flag.
bpo-47061: Deprecate the various modules listed by PEP 594:
aifc, asynchat, asyncore, audioop, cgi, cgitb, chunk, crypt, imghdr, msilib, nntplib, nis, ossaudiodev, pipes, smtpd, sndhdr, spwd, sunau, telnetlib, uu, xdrlib
bpo-2604: Fix bug where doctests using globals would fail when run multiple times.
bpo-45997: Fix
asyncio.Semaphore
re-aquiring FIFO order.bpo-47022: The
asynchat
,asyncore
andsmtpd
modules have been deprecated since at least Python 3.6. Their documentation has now been updated to note they will removed in Python 3.12 (PEP 594).bpo-46421: Fix a unittest issue where if the command was invoked as
python -m unittest
and the filename(s) began with a dot (.), aValueError
is returned.bpo-14156: argparse.FileType now supports an argument of '-' in binary mode, returning the .buffer attribute of sys.stdin/sys.stdout as appropriate. Modes including 'x' and 'a' are treated equivalently to 'w' when argument is '-'. Patch contributed by Josh Rosenberg
Python 3.9.11 final¶
Release date: 2022-03-16
Core and Builtins¶
bpo-46852: Rename the private undocumented
float.__set_format__()
method tofloat.__setformat__()
to fix a typo introduced in Python 3.7. The method is only used by test_float. Patch by Victor Stinner.bpo-46794: Bump up the libexpat version into 2.4.6
bpo-46762: Fix an assert failure in debug builds when a '<', '>', or '=' is the last character in an f-string that's missing a closing right brace.
bpo-46732: Correct the docstring for the
__bool__()
method. Patch by Jelle Zijlstra.bpo-40479: Add a missing call to
va_end()
inModules/_hashopenssl.c
.bpo-46615: When iterating over sets internally in
setobject.c
, acquire strong references to the resulting items from the set. This prevents crashes in corner-cases of various set operations where the set gets mutated.bpo-43721: Fix docstrings of
getter
,setter
, anddeleter
to clarify that they create a new copy of the property.bpo-46503: Fix an assert when parsing some invalid N escape sequences in f-strings.
bpo-46417: Fix a race condition on setting a type
__bases__
attribute: the internal functionadd_subclass()
now gets thePyTypeObject.tp_subclasses
member after callingPyWeakref_NewRef()
which can trigger a garbage collection which can indirectly modifyPyTypeObject.tp_subclasses
. Patch by Victor Stinner.bpo-46383: Fix invalid signature of
_zoneinfo
'smodule_free
function to resolve a crash on wasm32-emscripten platform.
Library¶
bpo-43253: Fix a crash when closing transports where the underlying socket handle is already invalid on the Proactor event loop.
bpo-47004: Apply bugfixes from importlib_metadata 4.11.3, including bugfix for EntryPoint.extras, which was returning match objects and not the extras strings.
bpo-46985: Upgrade pip wheel bundled with ensurepip (pip 22.0.4)
bpo-46968:
faulthandler
: On Linux 5.14 and newer, dynamically determine size of signal handler stack size CPython allocates usinggetauxval(AT_MINSIGSTKSZ)
. This changes allows for Python extension's request to Linux kernel to use AMX_TILE instruction set on Sapphire Rapids Xeon processor to succeed, unblocking use of the ISA in frameworks.bpo-46955: Expose
asyncio.base_events.Server
asasyncio.Server
. Patch by Stefan Zabka.bpo-46932: Update bundled libexpat to 2.4.7
bpo-25707: Fixed a file leak in
xml.etree.ElementTree.iterparse()
when the iterator is not exhausted. Patch by Jacob Walls.bpo-44886: Inherit asyncio proactor datagram transport from
asyncio.DatagramTransport
.bpo-46827: Support UDP sockets in
asyncio.loop.sock_connect()
for selector-based event loops. Patch by Thomas Grainger.bpo-46811: Make test suite support Expat >=2.4.5
bpo-46252: Raise
TypeError
ifssl.SSLSocket
is passed to transport-based APIs.bpo-46784: Fix libexpat symbols collisions with user dynamically loaded or statically linked libexpat in embedded Python.
bpo-39327:
shutil.rmtree()
can now work with VirtualBox shared folders when running from the guest operating-system.bpo-46756: Fix a bug in
urllib.request.HTTPPasswordMgr.find_user_password()
andurllib.request.HTTPPasswordMgrWithPriorAuth.is_authenticated()
which allowed to bypass authorization. For example, access to URIexample.org/foobar
was allowed if the user was authorized for URIexample.org/foo
.bpo-45863: When the
tarfile
module creates a pax format archive, it will put an integer representation of timestamps in the ustar header (if possible) for the benefit of older unarchivers, in addition to the existing full-precision timestamps in the pax extended header.bpo-46672: Fix
NameError
inasyncio.gather()
when initial type check fails.bpo-45948: Fixed a discrepancy in the C implementation of the
xml.etree.ElementTree
module. Now, instantiating anxml.etree.ElementTree.XMLParser
with atarget=None
keyword provides a defaultxml.etree.ElementTree.TreeBuilder
target as the Python implementation does.bpo-46591: Make the IDLE doc URL on the About IDLE dialog clickable.
bpo-46400: expat: Update libexpat from 2.4.1 to 2.4.4
bpo-46487: Add the
get_write_buffer_limits
method toasyncio.transports.WriteTransport
and to the SSL transport.bpo-46539: In
typing.get_type_hints()
, support evaluating stringifiedClassVar
andFinal
annotations insideAnnotated
. Patch by Gregory Beauregard.bpo-46491: Allow
typing.Annotated
to wraptyping.Final
andtyping.ClassVar
. Patch by Gregory Beauregard.bpo-46436: Fix command-line option
-d
/--directory
in modulehttp.server
which is ignored when combined with command-line option--cgi
. Patch by Géry Ogam.bpo-41403: Make
mock.patch()
raise aTypeError
with a relevant error message on invalid arg. Previously it allowed a crypticAttributeError
to escape.bpo-46474: In
importlib.metadata.EntryPoint.pattern
, avoid potential REDoS by limiting ambiguity in consecutive whitespace.bpo-46469:
asyncio
generic classes now returntypes.GenericAlias
in__class_getitem__
instead of the same class.bpo-46434:
pdb
now gracefully handleshelp
when__doc__
is missing, for example when run with pregenerated optimized.pyc
files.bpo-46333: The
__eq__()
and__hash__()
methods oftyping.ForwardRef
now honor themodule
parameter oftyping.ForwardRef
. Forward references from different modules are now differentiated.bpo-43118: Fix a bug in
inspect.signature()
that was causing it to fail on some subclasses of classes with a__text_signature__
referencing module globals. Patch by Weipeng Hong.bpo-21987: Fix an issue with
tarfile.TarFile.getmember()
getting a directory name with a trailing slash.bpo-20392: Fix inconsistency with uppercase file extensions in
MimeTypes.guess_type()
. Patch by Kumar Aditya.bpo-46080: Fix exception in argparse help text generation if a
argparse.BooleanOptionalAction
argument's default isargparse.SUPPRESS
and it hashelp
specified. Patch by Felix Fontein.bpo-44439: Fix
.write()
method of a member file inZipFile
, when the input data is an object that supports the buffer protocol, the file length may be wrong.bpo-45703: When a namespace package is imported before another module from the same namespace is created/installed in a different
sys.path
location while the program is running, calling theimportlib.invalidate_caches()
function will now also guarantee the new module is noticed.bpo-24959: Fix bug where
unittest
sometimes drops frames from tracebacks of exceptions raised in tests.
Documentation¶
bpo-46463: Fixes
escape4chm.py
script used when building the CHM documentation file
Tests¶
bpo-46913: Fix test_faulthandler.test_sigfpe() if Python is built with undefined behavior sanitizer (UBSAN): disable UBSAN on the faulthandler_sigfpe() function. Patch by Victor Stinner.
bpo-46708: Prevent default asyncio event loop policy modification warning after
test_asyncio
execution.bpo-46616: Ensures
test_importlib.test_windows
cleans up registry keys after completion.bpo-44359: test_ftplib now silently ignores socket errors to prevent logging unhandled threading exceptions. Patch by Victor Stinner.
bpo-46542: Fix a Python crash in test_lib2to3 when using Python built in debug mode: limit the recursion limit. Patch by Victor Stinner.
bpo-46576: test_peg_generator now disables compiler optimization when testing compilation of its own C extensions to significantly speed up the testing on non-debug builds of CPython.
bpo-46542: Fix
test_json
tests checking forRecursionError
: modify these tests to usesupport.infinite_recursion()
. Patch by Victor Stinner.bpo-13886: Skip test_builtin PTY tests on non-ASCII characters if the readline module is loaded. The readline module changes input() behavior, but test_builtin is not intented to test the readline module. Patch by Victor Stinner.
Build¶
bpo-47024: Update OpenSSL to 1.1.1n for macOS installers and all Windows builds.
bpo-38472: Fix GCC detection in setup.py when cross-compiling. The C compiler is now run with LC_ALL=C. Previously, the detection failed with a German locale.
bpo-46513: configure no longer uses
AC_C_CHAR_UNSIGNED
macro andpyconfig.h
no longer defines reserved symbol__CHAR_UNSIGNED__
.bpo-45925: Update Windows installer to use SQLite 3.37.2.
bpo-47032: Ensure Windows install builds fail correctly with a non-zero exit code when part of the build fails.
Windows¶
bpo-44549: Update bzip2 to 1.0.8 in Windows builds to mitigate CVE-2016-3189 and CVE-2019-12900
bpo-46948: Prevent CVE-2022-26488 by ensuring the Add to PATH option in the Windows installer uses the correct path when being repaired.
bpo-46638: Ensures registry virtualization is consistently disabled. For 3.10 and earlier, it remains enabled (some registry writes are protected), while for 3.11 and later it is disabled (registry modifications affect all applications).
macOS¶
bpo-45925: Update macOS installer to SQLite 3.37.2.
IDLE¶
bpo-46630: Make query dialogs on Windows start with a cursor in the entry box.
bpo-45296: Clarify close, quit, and exit in IDLE. In the File menu, 'Close' and 'Exit' are now 'Close Window' (the current one) and 'Exit' is now 'Exit IDLE' (by closing all windows). In Shell, 'quit()' and 'exit()' mean 'close Shell'. If there are no other windows, this also exits IDLE.
bpo-45447: Apply IDLE syntax highlighting to
pyi
files. Patch by Alex Waygood and Terry Jan Reedy.
Python 3.9.10 final¶
Release date: 2022-01-13
Core and Builtins¶
bpo-46070:
Py_EndInterpreter()
now explicitly untracks all objects currently tracked by the GC. Previously, if an object was used later by another interpreter, callingPyObject_GC_UnTrack()
on the object crashed if the previous or the next object of thePyGC_Head
structure became a dangling pointer. Patch by Victor Stinner.bpo-46085: Fix iterator cache mechanism of
OrderedDict
.bpo-46110: Add a maximum recursion check to the PEG parser to avoid stack overflow. Patch by Pablo Galindo
bpo-46000: Improve compatibility of the
curses
module with NetBSD curses.bpo-45614: Fix
traceback
display for exceptions with invalid module name.bpo-45806: Re-introduced fix that allows recovery from stack overflow without crashing the interpreter. The original fix as part of bpo-42500 was reverted (see release notes for Python 3.9.4) since it introduced an ABI change in a bugfix release which is not allowed. The new fix doesn't introduce any ABI changes. Patch by Mark Shannon.
bpo-45822: Fixed a bug in the parser that was causing it to not respect PEP 263 coding cookies when no flags are provided. Patch by Pablo Galindo
bpo-45820: Fix a segfault when the parser fails without reading any input. Patch by Pablo Galindo
bpo-42540: Fix crash when
os.fork()
is called with an active non-default memory allocator.
Library¶
bpo-40479: Fix
hashlib
usedforsecurity option to work correctly with OpenSSL 3.0.0 in FIPS mode.bpo-46070: Fix possible segfault when importing the
asyncio
module from different sub-interpreters in parallel. Patch by Erlend E. Aasland.bpo-46278: Reflect
context
argument inAbstractEventLoop.call_*()
methods. Loop implementations already support it.bpo-46239: Improve error message when importing
asyncio.windows_events
on non-Windows.bpo-20369:
concurrent.futures.wait()
no longer blocks forever when given duplicate Futures. Patch by Kumar Aditya.bpo-46105: Honor spec when generating requirement specs with urls and extras (importlib_metadata 4.8.3).
bpo-26952:
argparse
raisesValueError
with clear message when trying to render usage for an empty mutually-exclusive group. Previously it raised a crypticIndexError
.bpo-27718: Fix help for the
signal
module. Some functions (e.g.signal()
andgetsignal()
) were omitted.bpo-46032: The
registry()
method offunctools.singledispatch()
functions checks now the first argument or the first parameter annotation and raises a TypeError if it is not supported. Previously unsupported "types" were ignored (e.g.typing.List[int]
) or caused an error at calling time (e.g.list[int]
).bpo-46018: Ensure that
math.expm1()
does not raise on underflow.bpo-27946: Fix possible crash when getting an attribute of class:
xml.etree.ElementTree.Element
simultaneously with replacing theattrib
dict.bpo-13236:
unittest.TextTestResult
andunittest.TextTestRunner
flush now the output stream more often.bpo-37658: Fix issue when on certain conditions
asyncio.wait_for()
may allow a coroutine to complete successfully, but fail to return the result, potentially causing memory leaks or other issues.bpo-45831:
faulthandler
can now write ASCII-only strings (like filenames and function names) with a single write() syscall when dumping a traceback. It reduces the risk of getting an unreadable dump when two threads or two processes dump a traceback to the same file (like stderr) at the same time. Patch by Victor Stinner.bpo-41735: Fix thread lock in
zlib.Decompress.flush()
method beforePyObject_GetBuffer
.bpo-45664: Fix
types.resolve_bases()
andtypes.new_class()
fortypes.GenericAlias
instance as a base.bpo-45663: Fix
dataclasses.is_dataclass()
for dataclasses which are subclasses oftypes.GenericAlias
.bpo-45662: Fix the repr of
dataclasses.InitVar
with a type alias to the built-in class, e.g.InitVar[list[int]]
.bpo-43498: Avoid a possible "RuntimeError: dictionary changed size during iteration" when adjusting the process count of
ProcessPoolExecutor
.bpo-29620:
assertWarns()
no longer raises aRuntimeException
when accessing a module's__warningregistry__
causes importation of a new module, or when a new module is imported in another thread. Patch by Kernc.
Documentation¶
bpo-19737: Update the documentation for the
globals()
function.bpo-45840: Improve cross-references in the documentation for the data model.
bpo-45788: Link doc for sys.prefix to sysconfig doc on installation paths.
bpo-25381: In the extending chapter of the extending doc, update a paragraph about the global variables containing exception information.
bpo-43905: Expanded
astuple()
andasdict()
docs, warning about deepcopy being applied and providing a workaround.bpo-41028: Language and version switchers, previously maintained in every cpython branches, are now handled by docsbuild-script.
Tests¶
bpo-46205: Fix hang in runtest_mp due to race condition
bpo-46263: Fix test_capi on FreeBSD 14-dev: instruct jemalloc to not fill freed memory with junk byte.
bpo-46150: Now
fakename
intest_pathlib.PosixPathTest.test_expanduser
is checked to be non-existent.bpo-46129: Rewrite
asyncio.locks
tests withunittest.IsolatedAsyncioTestCase
usage.bpo-23819: Fixed
asyncio
tests in python optimized mode. Patch by Kumar Aditya.bpo-46114: Fix test case for OpenSSL 3.0.1 version. OpenSSL 3.0 uses
0xMNN00PP0L
.bpo-19460: Add new Test for
email.mime.nonmultipart.MIMENonMultipart
.bpo-45835: Fix race condition in test_queue tests with multiple "feeder" threads.
Build¶
bpo-46263:
configure
no longer setsMULTIARCH
on FreeBSD platforms.bpo-46106: Updated OpenSSL to 1.1.1m in Windows builds, macOS installer builds, and CI. Patch by Kumar Aditya.
bpo-44035: CI now verifies that autoconf files have been regenerated with a current and unpatched autoconf package.
bpo-33393: Update
config.guess
to 2021-06-03 andconfig.sub
to 2021-08-14.Makefile
now has anupdate-config
target to make updating more convenient.bpo-45866:
make regen-all
now produces the same output when run from a directory other than the source tree: when building Python out of the source tree. pegen now strips directory of the "generated by pygen from <FILENAME>" header Patch by Victor Stinner.bpo-41498: Python now compiles on platforms without
sigset_t
. Several functions insignal
are not available whensigset_t
is missing.Based on patch by Roman Yurchak for pyodide.
bpo-45881:
setup.py
now usesCC
from environment first to discover multiarch and cross compile paths.
Windows¶
bpo-45901: When installed through the Microsoft Store and set as the default app for
*.py
files, command line arguments will now be passed to Python when invoking a script without explicitly launching Python (that is,script.py args
rather thanpython script.py args
).
macOS¶
Tools/Demos¶
bpo-45838: Fix line number calculation when debugging Python with GDB.
C API¶
bpo-39026: Fix Python.h to build C extensions with Xcode: remove a relative include from
Include/cpython/pystate.h
.
Python 3.9.9 final¶
Release date: 2021-11-15
Core and Builtins¶
bpo-45738: Fix computation of error location for invalid continuation characters in the parser. Patch by Pablo Galindo.
Library¶
bpo-45235: Reverted an argparse bugfix that caused regression in the handling of default arguments for subparsers. This prevented leaf level arguments from taking precedence over root level arguments.
bpo-45765: In importlib.metadata, fix distribution discovery for an empty path.
bpo-45644: In-place JSON file formatting using
python3 -m json.tool infile infile
now works correctly, previously it left the file empty. Patch by Chris Wesseling.
Documentation¶
Windows¶
Python 3.9.8 final¶
Release date: 2021-11-05
Core and Builtins¶
bpo-30570: Fixed a crash in
issubclass()
from infinite recursion when searching pathological__bases__
tuples.bpo-45494: Fix parser crash when reporting errors involving invalid continuation characters. Patch by Pablo Galindo.
bpo-45385: Fix reference leak from descr_check. Patch by Dong-hee Na.
bpo-45167: Fix deepcopying of
types.GenericAlias
objects.bpo-44219: Release the GIL while performing
isatty
system calls on arbitrary file descriptors. In particular, this affectsos.isatty()
,os.device_encoding()
andio.TextIOWrapper
. By extension,io.open()
in text mode is also affected. This change solves a deadlock inos.isatty()
. Patch by Vincent Michel in bpo-44219.bpo-44959: Added fallback to extension modules with '.sl' suffix on HP-UX
bpo-44050: Extensions that indicate they use global state (by setting
m_size
to -1) can again be used in multiple interpreters. This reverts to behavior of Python 3.8.bpo-45121: Fix issue where
Protocol.__init__
raisesRecursionError
when it's called directly or viasuper()
. Patch provided by Yurii Karabas.bpo-45083: When the interpreter renders an exception, its name now has a complete qualname. Previously only the class name was concatenated to the module name, which sometimes resulted in an incorrect full name being displayed.
(This issue impacted only the C code exception rendering, the
traceback
module was using qualname already).
Library¶
bpo-45678: Fix bug in Python 3.9 that meant
functools.singledispatchmethod
failed to properly wrap the attributes of the target method. Patch by Alex Waygood.bpo-45679: Fix caching of multi-value
typing.Literal
.Literal[True, 2]
is no longer equal toLiteral[1, 2]
.bpo-45438: Fix typing.Signature string representation for generic builtin types.
bpo-45581:
sqlite3.connect()
now correctly raisesMemoryError
if the underlying SQLite API signals memory error. Patch by Erlend E. Aasland.bpo-39679: Fix bug in
functools.singledispatchmethod
that caused it to fail when attempting to register aclassmethod()
orstaticmethod()
using type annotations. Patch contributed by Alex Waygood.bpo-45515: Add references to
zoneinfo
in thedatetime
documentation, mostly replacing outdated references todateutil.tz
. Change by Paul Ganssle.bpo-45467: Fix incremental decoder and stream reader in the "raw-unicode-escape" codec. Previously they failed if the escape sequence was split.
bpo-45461: Fix incremental decoder and stream reader in the "unicode-escape" codec. Previously they failed if the escape sequence was split.
bpo-45239: Fixed
email.utils.parsedate_tz()
crashing withUnboundLocalError
on certain invalid input instead of returningNone
. Patch by Ben Hoyt.bpo-44904: Fix bug in the
doctest
module that caused it to fail if a docstring included an example with aclassmethod
property
. Patch by Alex Waygood.bpo-45406: Make
inspect.getmodule()
catchFileNotFoundError
raised by :'func:inspect.getabsfile
, and returnNone
to indicate that the module could not be determined.bpo-45262: Prevent use-after-free in asyncio. Make sure the cached running loop holder gets cleared on dealloc to prevent use-after-free in get_running_loop
bpo-45386: Make
xmlrpc.client
more robust to C runtimes where the underlying Cstrftime
function results in aValueError
when testing for year formatting options.bpo-45371: Fix clang rpath issue in
distutils
. The UnixCCompiler now uses correct clang option to add a runtime library directory (rpath) to a shared library.bpo-20028: Improve error message of
csv.Dialect
when initializing. Patch by Vajrasky Kok and Dong-hee Na.bpo-45343: Update bundled pip to 21.2.4 and setuptools to 58.1.0
bpo-41710: On Unix, if the
sem_clockwait()
function is available in the C library (glibc 2.30 and newer), thethreading.Lock.acquire()
method now uses the monotonic clock (time.CLOCK_MONOTONIC
) for the timeout, rather than using the system clock (time.CLOCK_REALTIME
), to not be affected by system clock changes. Patch by Victor Stinner.bpo-45328: Fixed
http.client.HTTPConnection
to work properly in OSs that don't support theTCP_NODELAY
socket option.bpo-1596321: Fix the
threading._shutdown()
function when thethreading
module was imported first from a thread different than the main thread: no longer log an error at Python exit.bpo-45274: Fix a race condition in the
Thread.join()
method of thethreading
module. If the function is interrupted by a signal and the signal handler raises an exception, make sure that the thread remains in a consistent state to prevent a deadlock. Patch by Victor Stinner.bpo-45238: Fix
unittest.IsolatedAsyncioTestCase.debug()
: it runs now asynchronous methods and callbacks.bpo-36674:
unittest.TestCase.debug()
raises now aunittest.SkipTest
if the class or the test method are decorated with the skipping decorator.bpo-45235: Fix an issue where argparse would not preserve values in a provided namespace when using a subparser with defaults.
bpo-45234: Fixed a regression in
copyfile()
,copy()
,copy2()
raisingFileNotFoundError
when source is a directory, which should raiseIsADirectoryError
bpo-45228: Fix stack buffer overflow in parsing J1939 network address.
bpo-45192: Fix the
tempfile._infer_return_type
function so that thedir
argument of thetempfile
functions accepts an object implementing theos.PathLike
protocol.Patch by Kyungmin Lee.
bpo-45160: When tracing a tkinter variable used by a ttk OptionMenu, callbacks are no longer made twice.
bpo-35474: Calling
mimetypes.guess_all_extensions()
withstrict=False
no longer affects the result of the following call withstrict=True
. Also, mutating the returned list no longer affects the global state.bpo-45166:
typing.get_type_hints()
now works withFinal
wrapped inForwardRef
.bpo-45097: Remove deprecation warnings about the loop argument in
asyncio
incorrectly emitted in cases when the user does not pass the loop argument.bpo-45081: Fix issue when dataclasses that inherit from
typing.Protocol
subclasses have wrong__init__
. Patch provided by Yurii Karabas.bpo-24444: Fixed an error raised in
argparse
help display when help for an option is set to 1+ blank spaces or when choices arg is an empty container.bpo-45021: Fix a potential deadlock at shutdown of forked children when using
concurrent.futures
modulebpo-45030: Fix integer overflow in pickling and copying the range iterator.
bpo-39039: tarfile.open raises
ReadError
when a zlib error occurs during file extraction.bpo-44594: Fix an edge case of
ExitStack
andAsyncExitStack
exception chaining. They will now matchwith
block behavior when__context__
is explicitly set toNone
when the exception is in flight.
Documentation¶
bpo-45726: Improve documentation for
functools.singledispatch()
andfunctools.singledispatchmethod
.bpo-45680: Amend the docs on
GenericAlias
objects to clarify that non-container classes can also implement__class_getitem__
. Patch contributed by Alex Waygood.bpo-45655: Add a new "relevant PEPs" section to the top of the documentation for the
typing
module. Patch by Alex Waygood.bpo-45604: Add
level
argument tomultiprocessing.log_to_stderr
function docs.bpo-45464: Mention in the documentation of Built-in Exceptions that inheriting from multiple exception types in a single subclass is not recommended due to possible memory layout incompatibility.
bpo-45449: Add note about PEP 585 in
collections.abc
.bpo-45516: Add protocol description to the
importlib.abc.Traversable
documentation.bpo-20692: Add Programming FAQ entry explaining that int literal attribute access requires either a space after or parentheses around the literal.
bpo-45216: Remove extra documentation listing methods in
difflib
. It was rendering twice in pydoc and was outdated in some places.
Tests¶
bpo-45578: Add tests for
dis.distb()
bpo-45577: Add subtests for all
pickle
protocols intest_zoneinfo
.bpo-43592:
test.libregrtest
now raises the soft resource limit for the maximum number of file descriptors when the default is too low for our test suite as was often the case on macOS.bpo-40173: Fix
test.support.import_helper.import_fresh_module()
.bpo-45280: Add a test case for empty
typing.NamedTuple
.bpo-45269: Cover case when invalid
markers
type is supplied toc_make_encoder
.bpo-45209: Fix
UserWarning: resource_tracker
warning in_test_multiprocessing._TestSharedMemory.test_shared_memory_cleaned_after_process_termination
bpo-45195: Fix test_readline.test_nonascii(): sometimes, the newline character is not written at the end, so don't expect it in the output. Patch by Victor Stinner.
bpo-45156: Fixes infinite loop on
unittest.mock.seal()
of mocks created bycreate_autospec()
.bpo-45042: Fixes that test classes decorated with
@hashlib_helper.requires_hashdigest
were skipped all the time.
Build¶
bpo-43158:
setup.py
now uses values from configure script to build the_uuid
extension module. Configure now detects util-linux'slibuuid
, too.bpo-45571:
Modules/Setup
now usePY_CFLAGS_NODIST
instead ofPY_CFLAGS
to compile shared modules.bpo-45532: Update
sys.version
to usemain
as fallback information. Patch by Jeong YunWon.bpo-45405: Prevent
internal configure error
when runningconfigure
with recent versions of non-Apple clang. Patch by David Bohman.bpo-45220: Avoid building with the Windows 11 SDK previews automatically. This may be overridden by setting the
DefaultWindowsSDKVersion
environment variable before building.
Windows¶
bpo-45337: venv now warns when the created environment may need to be accessed at a different path, due to redirections, links or junctions. It also now correctly installs or upgrades components when the alternate path is required.
macOS¶
bpo-44828: Avoid tkinter file dialog failure on macOS 12 Monterey when using the Tk 8.6.11 provided by python.org macOS installers. Patch by Marc Culler of the Tk project.
IDLE¶
bpo-45296: On Windows, change exit/quit message to suggest Ctrl-D, which works, instead of <Ctrl-Z Return>, which does not work in IDLE.
C API¶
bpo-44687:
BufferedReader.peek()
no longer raisesValueError
when the entire file has already been buffered.bpo-44751: Remove
crypt.h
include from the publicPython.h
header.
Python 3.9.7 final¶
Release date: 2021-08-30
Security¶
bpo-42278: Replaced usage of
tempfile.mktemp()
withTemporaryDirectory
to avoid a potential race condition.bpo-41180: Add auditing events to the
marshal
module, and stop raisingcode.__init__
events for every unmarshalled code object. Directly instantiated code objects will continue to raise an event, and audit event handlers should inspect or collect the raw marshal data. This reduces a significant performance overhead when loading from.pyc
files.bpo-44394: Update the vendored copy of libexpat to 2.4.1 (from 2.2.8) to get the fix for the CVE-2013-0340 "Billion Laughs" vulnerability. This copy is most used on Windows and macOS.
bpo-43124: Made the internal
putcmd
function insmtplib
sanitize input for presence of\r
and\n
characters to avoid (unlikely) command injection.
Core and Builtins¶
bpo-45018: Fixed pickling of range iterators that iterated for over 2**32 times.
bpo-44962: Fix a race in WeakKeyDictionary, WeakValueDictionary and WeakSet when two threads attempt to commit the last pending removal. This fixes asyncio.create_task and fixes a data loss in asyncio.run where shutdown_asyncgens is not run
bpo-44954: Fixed a corner case bug where the result of
float.fromhex('0x.8p-1074')
was rounded the wrong way.bpo-44947: Refine the syntax error for trailing commas in import statements. Patch by Pablo Galindo.
bpo-44698: Restore behaviour of complex exponentiation with integer-valued exponent of type
float
orcomplex
.bpo-44885: Correct the ast locations of f-strings with format specs and repeated expressions. Patch by Pablo Galindo
bpo-44872: Use new trashcan macros (Py_TRASHCAN_BEGIN/END) in frameobject.c instead of the old ones (Py_TRASHCAN_SAFE_BEGIN/END).
bpo-33930: Fix segmentation fault with deep recursion when cleaning method objects. Patch by Augusto Goulart and Pablo Galindo.
bpo-25782: Fix bug where
PyErr_SetObject
hangs when the current exception has a cycle in its context chain.bpo-44856: Fix reference leaks in the error paths of
update_bases()
and__build_class__
. Patch by Pablo Galindo.bpo-44698: Fix undefined behaviour in complex object exponentiation.
bpo-44562: Remove uses of
PyObject_GC_Del()
in error path when initializingtypes.GenericAlias
.bpo-44523: Remove the pass-through for
hash()
ofweakref.proxy
objects to prevent unintended consequences when the original referred object dies while the proxy is part of a hashable object. Patch by Pablo Galindo.bpo-44472: Fix ltrace functionality when exceptions are raised. Patch by Pablo Galindo
bpo-44184: Fix a crash at Python exit when a deallocator function removes the last strong reference to a heap type. Patch by Victor Stinner.
bpo-39091: Fix crash when using passing a non-exception to a generator's
throw()
method. Patch by Noah Oxer
Library¶
bpo-41620:
run()
now always return aTestResult
instance. Previously it returnedNone
if the test class or method was decorated with a skipping decorator.bpo-43913: Fix bugs in cleaning up classes and modules in
unittest
:Functions registered with
addModuleCleanup()
were not called unless the user definestearDownModule()
in their test module.Functions registered with
addClassCleanup()
were not called iftearDownClass
is set toNone
.Buffering in
TestResult
did not work with functions registered withaddClassCleanup()
andaddModuleCleanup()
.Errors in functions registered with
addClassCleanup()
andaddModuleCleanup()
were not handled correctly in buffered and debug modes.Errors in
setUpModule()
and functions registered withaddModuleCleanup()
were reported in wrong order.And several lesser bugs.
bpo-45001: Made email date parsing more robust against malformed input, namely a whitespace-only
Date:
header. Patch by Wouter Bolsterlee.bpo-44449: Fix a crash in the signal handler of the
faulthandler
module: no longer modify the reference count of frame objects. Patch by Victor Stinner.bpo-44955: Method
stopTestRun()
is now always called in pair with methodstartTestRun()
forTestResult
objects implicitly created inrun()
. Previously it was not called for test methods and classes decorated with a skipping decorator.bpo-38956:
argparse.BooleanOptionalAction
's default value is no longer printed twice when used withargparse.ArgumentDefaultsHelpFormatter
.bpo-44581: Upgrade bundled pip to 21.2.3 and setuptools to 57.4.0
bpo-44849: Fix the
os.set_inheritable()
function on FreeBSD 14 for file descriptor opened with theO_PATH
flag: ignore theEBADF
error onioctl()
, fallback on thefcntl()
implementation. Patch by Victor Stinner.bpo-44605: The @functools.total_ordering() decorator now works with metaclasses.
bpo-44822:
sqlite3
user-defined functions and aggregators returningstrings
with embedded NUL characters are no longer truncated. Patch by Erlend E. Aasland.bpo-44815: Always show
loop=
arg deprecations inasyncio.gather()
andasyncio.sleep()
bpo-44806: Non-protocol subclasses of
typing.Protocol
ignore now the__init__
method inherited from protocol base classes.bpo-44667: The
tokenize.tokenize()
doesn't incorrectly generate aNEWLINE
token if the source doesn't end with a new line character but the last line is a comment, as the function is already generating aNL
token. Patch by Pablo Galindobpo-42853: Fix
http.client.HTTPSConnection
fails to download >2GiB data.bpo-44752:
rcompleter
does not callgetattr()
onproperty
objects to avoid the side-effect of evaluating the corresponding method.bpo-44720:
weakref.proxy
objects referencing non-iterators now raiseTypeError
rather than dereferencing the nulltp_iternext
slot and crashing.bpo-44704: The implementation of
collections.abc.Set._hash()
now matches that offrozenset.__hash__()
.bpo-44666: Fixed issue in
compileall.compile_file()
whensys.stdout
is redirected. Patch by Stefan Hölzl.bpo-40897: Give priority to using the current class constructor in
inspect.signature()
. Patch by Weipeng Hong.bpo-44608: Fix memory leak in
_tkinter._flatten()
if it is called with a sequence or set, but not list or tuple.bpo-41928: Update
shutil.copyfile()
to raiseFileNotFoundError
instead of confusingIsADirectoryError
when a path ending with aos.path.sep
does not exist;shutil.copy()
andshutil.copy2()
are also affected.bpo-44566: handle StopIteration subclass raised from @contextlib.contextmanager generator
bpo-44558: Make the implementation consistency of
indexOf()
between C and Python versions. Patch by Dong-hee Na.bpo-41249: Fixes
TypedDict
to work withtyping.get_type_hints()
and postponed evaluation of annotations across modules.bpo-44461: Fix bug with
pdb
's handling of import error due to a package which does not have a__main__
modulebpo-42892: Fixed an exception thrown while parsing a malformed multipart email by
email.message.EmailMessage
.bpo-27827:
pathlib.PureWindowsPath.is_reserved()
now identifies a greater range of reserved filenames, including those with trailing spaces or colons.bpo-34266: Handle exceptions from parsing the arg of
pdb
's run/restart command.bpo-27334: The
sqlite3
context manager now performs a rollback (thus releasing the database lock) if commit failed. Patch by Luca Citi and Erlend E. Aasland.bpo-43853: Improved string handling for
sqlite3
user-defined functions and aggregates:It is now possible to pass strings with embedded null characters to UDFs
Conversion failures now correctly raise
MemoryError
Patch by Erlend E. Aasland.
bpo-43048: Handle
RecursionError
inTracebackException
's constructor, so that long exceptions chains are truncated instead of causing traceback formatting to fail.bpo-41402: Fix
email.message.EmailMessage.set_content()
when called with binary data and7bit
content transfer encoding.bpo-32695: The compresslevel and preset keyword arguments of
tarfile.open()
are now both documented and tested.bpo-34990: Fixed a Y2k38 bug in the compileall module where it would fail to compile files with a modification time after the year 2038.
bpo-38840: Fix
test___all__
on platforms lacking a shared memory implementation.bpo-30256: Pass multiprocessing BaseProxy argument
manager_owned
through AutoProxy.bpo-27513:
email.utils.getaddresses()
now acceptsemail.header.Header
objects along with string values. Patch by Zackery Spytz.bpo-33349: lib2to3 now recognizes async generators everywhere.
bpo-29298: Fix
TypeError
when required subparsers withoutdest
do not receive arguments. Patch by Anthony Sottile.
Documentation¶
bpo-44903: Removed the othergui.rst file, any references to it, and the list of GUI frameworks in the FAQ. In their place I've added links to the Python Wiki
page on GUI frameworks
.bpo-44693: Update the definition of __future__ in the glossary by replacing the confusing word "pseudo-module" with a more accurate description.
bpo-35183: Add typical examples to os.path.splitext docs
bpo-30511: Clarify that
shutil.make_archive()
is not thread-safe due to reliance on changing the current working directory.bpo-44561: Update of three expired hyperlinks in Doc/distributing/index.rst: "Project structure", "Building and packaging the project", and "Uploading the project to the Python Packaging Index".
bpo-42958: Updated the docstring and docs of
filecmp.cmp()
to be more accurate and less confusing especially in respect to shallow arg.bpo-44558: Match the docstring and python implementation of
countOf()
to the behavior of its c implementation.bpo-44544: List all kwargs for
textwrap.wrap()
,textwrap.fill()
, andtextwrap.shorten()
. Now, there are nav links to attributes ofTextWrap
, which makes navigation much easier while minimizing duplication in the documentation.bpo-38062: Clarify that atexit uses equality comparisons internally.
bpo-43066: Added a warning to
zipfile
docs: filename arg with a leading slash may cause archive to be un-openable on Windows systems.bpo-27752: Documentation of csv.Dialect is more descriptive.
bpo-44453: Fix documentation for the return type of
sysconfig.get_path()
.bpo-39498: Add a "Security Considerations" index which links to standard library modules that have explicitly documented security considerations.
bpo-33479: Remove the unqualified claim that tkinter is threadsafe. It has not been true for several years and likely never was. An explanation of what is true may be added later, after more discussion, and possibly after patching _tkinter.c,
Tests¶
bpo-25130: Add calls of
gc.collect()
in tests to support PyPy.bpo-45011: Made tests relying on the
_asyncio
C extension module optional to allow running on alternative Python implementations. Patch by Serhiy Storchaka.bpo-44949: Fix auto history tests of test_readline: sometimes, the newline character is not written at the end, so don't expect it in the output.
bpo-44852: Add ability to wholesale silence DeprecationWarnings while running the regression test suite.
bpo-40928: Notify users running test_decimal regression tests on macOS of potential harmless "malloc can't allocate region" messages spewed by test_decimal.
bpo-44734: Fixed floating point precision issue in turtle tests.
bpo-44708: Regression tests, when run with -w, are now re-running only the affected test methods instead of re-running the entire test file.
bpo-30256: Add test for nested queues when using
multiprocessing
shared objectsAutoProxy[Queue]
insideListProxy
andDictProxy
Build¶
Windows¶
bpo-45007: Update to OpenSSL 1.1.1l in Windows build
bpo-44572: Avoid consuming standard input in the
platform
modulebpo-40263: This is a follow-on bug from https://bugs.python.org/issue26903. Once that is applied we run into an off-by-one assertion problem. The assert was not correct.
macOS¶
bpo-45007: Update macOS installer builds to use OpenSSL 1.1.1l.
bpo-44689:
ctypes.util.find_library()
now works correctly on macOS 11 Big Sur even if Python is built on an older version of macOS. Previously, when built on older macOS systems,find_library
was not able to find macOS system libraries when running on Big Sur due to changes in how system libraries are stored.
Python 3.9.6 final¶
Release date: 2021-06-28
Security¶
bpo-44022: mod:
http.client
now avoids infinitely reading potential HTTP headers after a100 Continue
status response from the server.
Core and Builtins¶
bpo-44409: Fix error location information for tokenizer errors raised on initialization of the tokenizer. Patch by Pablo Galindo.
bpo-43667: Improve Unicode support in non-UTF locales on Oracle Solaris. This issue does not affect other Solaris systems.
bpo-44168: Fix error message in the parser involving keyword arguments with invalid expressions. Patch by Pablo Galindo
bpo-44114: Fix incorrect dictkeys_reversed and dictitems_reversed function signatures in C code, which broke webassembly builds.
bpo-44070: No longer eagerly makes import filenames absolute, except for extension modules, which was introduced in 3.9.5.
bpo-28146: Fix a confusing error message in
str.format()
.bpo-11105: When compiling
ast.AST
objects with recursive references throughcompile()
, the interpreter doesn't crash anymore instead it raises aRecursionError
.
Library¶
bpo-44516: Update vendored pip to 21.1.3
bpo-44482: Fix very unlikely resource leak in
glob
in alternate Python implementations.bpo-44439: Fix in
bz2.BZ2File.write()
/lzma.LZMAFile.write()
methods, when the input data is an object that supports the buffer protocol, the file length may be wrong.bpo-44434: _thread.start_new_thread() no longer calls PyThread_exit_thread() explicitly at the thread exit, the call was redundant. On Linux with the glibc, pthread_exit() aborts the whole process if dlopen() fails to open libgcc_s.so file (ex: EMFILE error). Patch by Victor Stinner.
bpo-44422: The
threading.enumerate()
function now uses a reentrant lock to prevent a hang on reentrant call. Patch by Victor Stinner.bpo-44395: Fix
as_string()
to pass unixfrom properly. Patch by Dong-hee Na.bpo-44342: [Enum] Be more robust in searching for pickle support before making an enum class unpicklable.
bpo-44356: [Enum] Allow multiple data-type mixins if they are all the same.
bpo-44254: On Mac, give turtledemo button text a color that works on both light or dark background. Programmers cannot control the latter.
bpo-44145:
hmac
computations were not releasing the GIL while calling the OpenSSLHMAC_Update
C API (a new feature in 3.9). This unintentionally prevented parallel computation as otherhashlib
algorithms support.bpo-37788: Fix a reference leak when a Thread object is never joined.
bpo-44061: Fix regression in previous release when calling
pkgutil.iter_modules()
with a list ofpathlib.Path
objectsbpo-36515: The
hashlib
module no longer does unaligned memory accesses when compiled for ARM platforms.bpo-44018: random.seed() no longer mutates bytearray inputs.
bpo-38352: Add
IO
,BinaryIO
,TextIO
,Match
, andPattern
totyping.__all__
. Patch by Jelle Zijlstra.bpo-43972: When
http.server.SimpleHTTPRequestHandler
sends a301 (Moved Permanently)
for a directory path not ending with/
, add aContent-Length: 0
header. This improves the behavior for certain clients.bpo-28528: Fix a bug in
pdb
wherecheckline()
raisesAttributeError
if it is called afterreset()
.bpo-43776: When
subprocess.Popen
args are provided as a string or aspathlib.Path
, the Popen instance repr now shows the right thing.bpo-43666: AIX:
Lib/_aix_support.get_platform()
may fail in an AIX WPAR. The fileset bos.rte appears to have a builddate in both LPAR and WPAR so this fileset is queried rather than bos.mp64. To prevent a similiar situation (no builddate in ODM) a value (9988) sufficient for completing a build is provided. Patch by M Felt.bpo-43650: Fix
MemoryError
inshutil.unpack_archive()
which fails insideshutil._unpack_zipfile()
on large files. Patch by Igor Bolshakov.bpo-43318: Fix a bug where
pdb
does not always echo cleared breakpoints.bpo-43295:
datetime.datetime.strptime()
now raisesValueError
instead ofIndexError
when matching'z'
with the%z
format specifier.bpo-37022:
pdb
now displays exceptions fromrepr()
with itsp
andpp
commands.
Documentation¶
bpo-40620: Convert examples in tutorial controlflow.rst section 4.3 to be interpreter-demo style.
bpo-13814: In the Design FAQ, answer "Why don't generators support the with statement?"
bpo-44392: Added a new section in the C API documentation for types used in type hinting. Documented
Py_GenericAlias
andPy_GenericAliasType
.bpo-38291: Mark
typing.io
andtyping.re
as deprecated since Python 3.8 in the documentation. They were never properly supported by type checkers.bpo-44322: Document that SyntaxError args have a details tuple and that details are adjusted for errors in f-string field replacement expressions.
bpo-44195: Corrected references to
TraversableResources
in docs. There is noTraversableReader
.bpo-41963: Document that
ConfigParser
strips off comments when reading configuration files.bpo-44072: Correct where in the numeric ABC hierarchy
**
support is added, i.e., in numbers.Complex, not numbers.Integral.bpo-43558: Add the remark to
dataclasses
documentation that the__init__()
of any base class has to be called in__post_init__()
, along with a code example.bpo-41621: Document that
collections.defaultdict
parameterdefault_factory
defaults to None and is positional-only.
Tests¶
bpo-44287: Fix asyncio test_popen() of test_windows_utils by using a longer timeout. Use military grade battle-tested
test.support.SHORT_TIMEOUT
timeout rather than a hardcoded timeout of 10 seconds: it's 30 seconds by default, but it is made longer on slow buildbots. Patch by Victor Stinner.bpo-44363: Account for address sanitizer in test_capi. test_capi now passes when run GCC address sanitizer.
Build¶
bpo-44381: The Windows build now accepts
EnableControlFlowGuard
set toguard
to enable CFG.
Windows¶
bpo-41299: Fix 16ms jitter when using timeouts in
threading
, such as withthreading.Lock.acquire()
orthreading.Condition.wait()
.
macOS¶
IDLE¶
bpo-40128: Mostly fix completions on macOS when not using tcl/tk 8.6.11 (as with 3.9). The added update_idletask call should be harmless and possibly helpful otherwise.
bpo-33962: Move the indent space setting from the Font tab to the new Windows tab. Patch by Mark Roseman and Terry Jan Reedy.
bpo-40468: Split the settings dialog General tab into Windows and Shell/ED tabs. Move help sources, which extend the Help menu, to the Extensions tab. Make space for new options and shorten the dialog. The latter makes the dialog better fit small screens.
bpo-41611: Avoid uncaught exceptions in
AutoCompleteWindow.winconfig_event()
.bpo-41611: Fix IDLE sometimes freezing upon tab-completion on macOS.
Tools/Demos¶
bpo-44074: Make patchcheck automatically detect the correct base branch name (previously it was hardcoded to 'master')
C API¶
bpo-44441:
Py_RunMain()
now resetsPyImport_Inittab
to its initial value at exit. It must be possible to callPyImport_AppendInittab()
orPyImport_ExtendInittab()
at each Python initialization. Patch by Victor Stinner.bpo-42083: Fix crash in
PyStructSequence_NewType()
when passedNULL
in the documentation string slot.
Python 3.9.5 final¶
Release date: 2021-05-03
Security¶
bpo-43434: Creating a
sqlite3.Connection
object now also produces asqlite3.connect
auditing event. Previously this event was only produced bysqlite3.connect()
calls. Patch by Erlend E. Aasland.bpo-43882: The presence of newline or tab characters in parts of a URL could allow some forms of attacks.
Following the controlling specification for URLs defined by WHATWG
urllib.parse()
now removes ASCII newlines and tabs from URLs, preventing such attacks.bpo-43472: Ensures interpreter-level audit hooks receive the
cpython.PyInterpreterState_New
event when called through the_xxsubinterpreters
module.bpo-36384:
ipaddress
module no longer accepts any leading zeros in IPv4 address strings. Leading zeros are ambiguous and interpreted as octal notation by some libraries. For example the legacy functionsocket.inet_aton()
treats leading zeros as octal notatation. glibc implementation of moderninet_pton()
does not accept any leading zeros. For a while theipaddress
module used to accept ambiguous leading zeros.bpo-43075: Fix Regular Expression Denial of Service (ReDoS) vulnerability in
urllib.request.AbstractBasicAuthHandler
. The ReDoS-vulnerable regex has quadratic worst-case complexity and it allows cause a denial of service when identifying crafted invalid RFCs. This ReDoS issue is on the client side and needs remote attackers to control the HTTP server.bpo-42800: Audit hooks are now fired for frame.f_code, traceback.tb_frame, and generator code/frame attribute access.
Core and Builtins¶
bpo-43105: Importlib now resolves relative paths when creating module spec objects from file locations.
bpo-42924: Fix
bytearray
repetition incorrectly copying data from the start of the buffer, even if the data is offset within the buffer (e.g. after reassigning a slice at the start of thebytearray
to a shorter byte string).
Library¶
bpo-43993: Update bundled pip to 21.1.1.
bpo-43937: Fixed the
turtle
module working with non-default root window.bpo-43930: Update bundled pip to 21.1 and setuptools to 56.0.0
bpo-43920: OpenSSL 3.0.0:
load_verify_locations()
now returns a consistent error message when cadata contains no valid certificate.bpo-43607:
urllib
can now convert Windows paths with\\?\
prefixes into URL paths.bpo-43284: platform.win32_ver derives the windows version from sys.getwindowsversion().platform_version which in turn derives the version from kernel32.dll (which can be of a different version than Windows itself). Therefore change the platform.win32_ver to determine the version using the platform module's _syscmd_ver private function to return an accurate version.
bpo-42248: [Enum] ensure exceptions raised in
_missing_
are released.bpo-43799: OpenSSL 3.0.0: define
OPENSSL_API_COMPAT
1.1.1 to suppress deprecation warnings. Python requires OpenSSL 1.1.1 APIs.bpo-43794: Add
ssl.OP_IGNORE_UNEXPECTED_EOF
constants (OpenSSL 3.0.0)bpo-43789: OpenSSL 3.0.0: Don't call the password callback function a second time when first call has signaled an error condition.
bpo-43788: The header files for
ssl
error codes are now OpenSSL version-specific. Exceptions will now show correct reason and library codes. Themake_ssl_data.py
script has been rewritten to use OpenSSL's text file with error codes.bpo-43655:
tkinter
dialog windows are now recognized as dialogs by window managers on macOS and X Window.bpo-43534:
turtle.textinput()
andturtle.numinput()
create now a transient window working on behalf of the canvas window.bpo-43522: Fix problem with
hostname_checks_common_name
. OpenSSL does not copy hostflags from struct SSL_CTX to struct SSL.bpo-42967: Allow
bytes
separator
argument inurllib.parse.parse_qs
andurllib.parse.parse_qsl
when parsingstr
query strings. Previously, this raised aTypeError
.bpo-43176: Fixed processing of a dataclass that inherits from a frozen dataclass with no fields. It is now correctly detected as an error.
bpo-41735: Fix thread locks in zlib module may go wrong in rare case. Patch by Ma Lin.
bpo-36470: Fix dataclasses with
InitVar
s andreplace()
. Patch by Claudiu Popa.bpo-32745: Fix a regression in the handling of ctypes'
ctypes.c_wchar_p
type: embedded null characters would cause aValueError
to be raised. Patch by Zackery Spytz.
Documentation¶
bpo-43959: The documentation on the PyContextVar C-API was clarified.
bpo-43938: Update dataclasses documentation to express that FrozenInstanceError is derived from AttributeError.
bpo-43755: Update documentation to reflect that unparenthesized lambda expressions can no longer be the expression part in an
if
clause in comprehensions and generator expressions since Python 3.9.bpo-43739: Fixing the example code in Doc/extending/extending.rst to declare and initialize the pmodule variable to be of the right type.
Tests¶
bpo-43961: Fix test_logging.test_namer_rotator_inheritance() on Windows: use
os.replace()
rather thanos.rename()
. Patch by Victor Stinner.bpo-43842: Fix a race condition in the SMTP test of test_logging. Don't close a file descriptor (socket) from a different thread while asyncore.loop() is polling the file descriptor. Patch by Victor Stinner.
bpo-43811: Tests multiple OpenSSL versions on GitHub Actions. Use ccache to speed up testing.
bpo-43791: OpenSSL 3.0.0: Disable testing of legacy protocols TLS 1.0 and 1.1. Tests are failing with TLSV1_ALERT_INTERNAL_ERROR.
Windows¶
bpo-35306: Avoid raising errors from
pathlib.Path.exists()
when passed an invalid filename.bpo-38822: Fixed
os.stat()
failing on inaccessible directories with a trailing slash, rather than falling back to the parent directory's metadata. This implicitly affectedos.path.exists()
andos.path.isdir()
.bpo-26227: Fixed decoding of host names in
socket.gethostbyaddr()
andsocket.gethostbyname_ex()
.bpo-40432: Updated pegen regeneration script on Windows to find and use Python 3.8 or higher. Prior to this, pegen regeneration already required 3.8 or higher, but the script may have used lower versions of Python.
bpo-43745: Actually updates Windows release to OpenSSL 1.1.1k. Earlier releases were mislabelled and actually included 1.1.1i again.
bpo-43492: Upgrade Windows installer to use SQLite 3.35.5.
macOS¶
bpo-42119: Fix check for macOS SDK paths when building Python. Narrow search to match contents of SDKs, namely only files in
/System/Library
,/System/IOSSupport
, and/usr
other than/usr/local
. Previously, anything under/System
was assumed to be in an SDK which causes problems with the new file system layout in 10.15+ where user file systems may appear to be mounted under/System
. Paths in/Library
were also incorrectly treated as SDK locations.bpo-44009: Provide "python3.x-intel64" executable to allow reliably forcing macOS universal2 framework builds to run under Rosetta 2 Intel-64 emulation on Apple Silicon Macs. This can be useful for testing or when universal2 wheels are not yet available.
bpo-43492: Update macOS installer to use SQLite 3.35.4.
IDLE¶
bpo-43655: IDLE dialog windows are now recognized as dialogs by window managers on macOS and X Window.
Python 3.9.4 final¶
Release date: 2021-04-04
Core and Builtins¶
bpo-43710: Reverted the fix for https://bugs.python.org/issue42500 as it changed the PyThreadState struct size and broke the 3.9.x ABI in the 3.9.3 release (visible on 32-bit platforms using binaries compiled using an earlier version of Python 3.9.x headers).
Library¶
Python 3.9.3 final¶
Release date: 2021-04-02
Security¶
bpo-42988: CVE-2021-3426: Remove the
getfile
feature of thepydoc
module which could be abused to read arbitrary files on the disk (directory traversal vulnerability). Moreover, even source code of Python modules can contain sensitive data like passwords. Vulnerability reported by David Schwörer.bpo-43285:
ftplib
no longer trusts the IP address value returned from the server in response to the PASV command by default. This prevents a malicious FTP server from using the response to probe IPv4 address and port combinations on the client network.Code that requires the former vulnerable behavior may set a
trust_server_pasv_ipv4_address
attribute on theirftplib.FTP
instances toTrue
to re-enable it.bpo-43439: Add audit hooks for
gc.get_objects()
,gc.get_referrers()
andgc.get_referents()
. Patch by Pablo Galindo.
Core and Builtins¶
bpo-43660: Fix crash that happens when replacing
sys.stderr
with a callable that can remove the object while an exception is being printed. Patch by Pablo Galindo.bpo-43555: Report the column offset for
SyntaxError
for invalid line continuation characters. Patch by Pablo Galindo.bpo-43517: Fix misdetection of circular imports when using
from pkg.mod import attr
, which caused false positives in non-trivial multi-threaded code.bpo-35883: Python no longer fails at startup with a fatal error if a command line argument contains an invalid Unicode character. The
Py_DecodeLocale()
function now escapes byte sequences which would be decoded as Unicode characters outside the [U+0000; U+10ffff] range.bpo-43406: Fix a possible race condition where
PyErr_CheckSignals
tries to execute a non-Python signal handler.bpo-42500: Improve handling of exceptions near recursion limit. Converts a number of Fatal Errors in RecursionErrors.
Library¶
bpo-43433:
xmlrpc.client.ServerProxy
no longer ignores query and fragment in the URL of the server.bpo-35930: Raising an exception raised in a "future" instance will create reference cycles.
bpo-43577: Fix deadlock when using
ssl.SSLContext
debug callback withssl.SSLContext.sni_callback()
.bpo-43521:
ast.unparse
can now render NaNs and empty sets.bpo-43423:
subprocess.communicate()
no longer raises an IndexError when there is an empty stdout or stderr IO buffer during a timeout on Windows.bpo-27820: Fixed long-standing bug of smtplib.SMTP where doing AUTH LOGIN with initial_response_ok=False will fail.
The cause is that SMTP.auth_login _always_ returns a password if provided with a challenge string, thus non-compliant with the standard for AUTH LOGIN.
Also fixes bug with the test for smtpd.
bpo-43332: Improves the networking efficiency of
http.client
when using a proxy viaset_tunnel()
. Fewer small send calls are made during connection setup.bpo-43399: Fix
ElementTree.extend
not working on iterators when using the Python implementationbpo-43316: The
python -m gzip
command line application now properly fails when detecting an unsupported extension. It exits with a non-zero exit code and prints an error message to stderr.bpo-43260: Fix TextIOWrapper can not flush internal buffer forever after very large text is written.
bpo-42782: Fail fast in
shutil.move()
to avoid creating destination directories on failure.bpo-37193: Fixed memory leak in
socketserver.ThreadingMixIn
introduced in Python 3.7.
Documentation¶
bpo-43199: Answer "Why is there no goto?" in the Design and History FAQ.
bpo-43407: Clarified that a result from
time.monotonic()
,time.perf_counter()
,time.process_time()
, ortime.thread_time()
can be compared with the result from any following call to the same function - not just the next immediate call.bpo-27646: Clarify that 'yield from <expr>' works with any iterable, not just iterators.
bpo-36346: Update some deprecated unicode APIs which are documented as "will be removed in 4.0" to "3.12". See PEP 623 for detail.
Tests¶
bpo-37945: Fix test_getsetlocale_issue1813() of test_locale: skip the test if
setlocale()
fails. Patch by Victor Stinner.bpo-41561: Add workaround for Ubuntu's custom OpenSSL security level policy.
bpo-43288: Fix test_importlib to correctly skip Unicode file tests if the fileystem does not support them.
Build¶
macOS¶
bpo-41837: Update macOS installer build to use OpenSSL 1.1.1j.
IDLE¶
bpo-42225: Document that IDLE can fail on Unix either from misconfigured IP masquerage rules or failure displaying complex colored (non-ascii) characters.
bpo-43283: Document why printing to IDLE's Shell is often slower than printing to a system terminal and that it can be made faster by pre-formatting a single string before printing.
Python 3.9.2 final¶
Release date: 2021-02-19
Windows¶
bpo-43155:
PyCMethod_New()
is now present inpython3.lib
.
Python 3.9.2 release candidate 1¶
Release date: 2021-02-16
Security¶
bpo-42967: Fix web cache poisoning vulnerability by defaulting the query args separator to
&
, and allowing the user to choose a custom separator.bpo-42938: Avoid static buffers when computing the repr of
ctypes.c_double
andctypes.c_longdouble
values.
Core and Builtins¶
bpo-42819:
readline
: Explicitly disable bracketed paste in the interactive interpreter, even if it's set in the inputrc, is enabled by default (eg GNU Readline 8.1), or a user callsreadline.read_init_file()
. The Python REPL has not implemented bracketed paste support. Also, bracketed mode writes the"\x1b[?2004h"
escape sequence into stdout which causes test failures in applications that don't support it. It can still be explicitly enabled by callingreadline.parse_and_bind("set enable-bracketed-paste on")
. Patch by Dustin Rodrigues.bpo-42806: Fix the column offsets for f-strings
ast
nodes surrounded by parentheses and for nodes that spawn multiple lines. Patch by Pablo Galindo.bpo-40631: Fix regression where a single parenthesized starred expression was a valid assignment target.
bpo-32381: Fix encoding name when running a
.pyc
file on Windows:PyRun_SimpleFileExFlags()
now uses the correct encoding to decode the filename.bpo-42536: Several built-in and standard library types now ensure that their internal result tuples are always tracked by the garbage collector:
Previously, they could have become untracked by a prior garbage collection. Patch by Brandt Bucher.
bpo-42195: The
__args__
of the parameterized generics fortyping.Callable
andcollections.abc.Callable
are now consistent. The__args__
forcollections.abc.Callable
are now flattened whiletyping.Callable
's have not changed. To allow this change,types.GenericAlias
can now be subclassed andcollections.abc.Callable
's__class_getitem__
will now return a subclass oftypes.GenericAlias
. Tests for typing were also updated to not subclass things likeCallable[..., T]
as that is not a valid base class. Finally, both types no longer validate theirargtypes
, inCallable[[argtypes], resulttype]
to prepare for PEP 612. Patch by Ken Jin.
Library¶
bpo-43102: The namedtuple __new__ method had its __builtins__ set to None instead of an actual dictionary. This created problems for introspection tools.
bpo-43108: Fixed a reference leak in the
curses
module. Patch by Pablo Galindobpo-42944: Fix
random.Random.sample
whencounts
argument is notNone
.bpo-42931: Add
randbytes()
torandom.__all__
.bpo-42780: Fix os.set_inheritable() for O_PATH file descriptors on Linux.
bpo-42851: remove __init_subclass__ support for Enum members
bpo-41748: Fix HTMLParser parsing rules for element attributes containing commas with spaces. Patch by Karl Dubost.
bpo-42759: Fixed equality comparison of
tkinter.Variable
andtkinter.font.Font
. Objects which belong to different Tcl interpreters are now always different, even if they have the same name.bpo-42756: Configure LMTP Unix-domain socket to use socket global default timeout when a timeout is not explicitly provided.
bpo-23328: Allow / character in username, password fields on _PROXY envars.
bpo-42655:
subprocess
extra_groups is now correctly passed into setgroups() system call.bpo-42727:
EnumMeta.__prepare__
now accepts**kwds
to properly support__init_subclass__
bpo-42681: Fixed range checks for color and pair numbers in
curses
.bpo-37961: Fix crash in
tracemalloc.Traceback.__repr__()
(regressed in Python 3.9).bpo-42630:
tkinter
functions and constructors which need a default root window raise nowRuntimeError
with descriptive message instead of obscureAttributeError
orNameError
if it is not created yet or cannot be created automatically.bpo-42644:
logging.disable
will now validate the types and value of its parameter. It also now accepts strings representing the levels (as doesloging.setLevel
) instead of only the numerical values.bpo-36541: Fixed lib2to3.pgen2 to be able to parse PEP-570 positional only argument syntax.
bpo-42517: Enum: private names will raise a DeprecationWarning; in 3.10 they will become normal attributes
bpo-42678:
Enum
: call__init_subclass__
after members have been addedbpo-42532: Remove unexpected call of
__bool__
when passing aspec_arg
argument to a Mock.bpo-42388: Fix subprocess.check_output(..., input=None) behavior when text=True to be consistent with that of the documentation and universal_newlines=True.
bpo-34463: Fixed discrepancy between
traceback
and the interpreter in formatting of SyntaxError with lineno not set (traceback
was changed to match interpreter).bpo-42375: subprocess module update for DragonFlyBSD support.
bpo-42384: Make pdb populate sys.path[0] exactly the same as regular python execution.
bpo-42383: Fix pdb: previously pdb would fail to restart the debugging target if it was specified using a relative path and the current directory changed.
bpo-42318: Fixed support of non-BMP characters in
tkinter
on macOS.bpo-42163: Restore compatibility for
uname_result
around deepcopy and _replace.bpo-39825: Windows: Change
sysconfig.get_config_var('EXT_SUFFIX')
to the expected fullplatform_tag.extension
format. Previously it was hard-coded to.pyd
, now it is compatible withdistutils.sysconfig
and will result in something like.cp38-win_amd64.pyd
. This brings windows into conformance with the other platforms.bpo-42059:
typing.TypedDict
types created using the alternative call-style syntax now correctly respect thetotal
keyword argument when setting their__required_keys__
and__optional_keys__
class attributes.bpo-39101: Fixed tests using IsolatedAsyncioTestCase from hanging on BaseExceptions.
bpo-42005: Fix CLI of
cProfile
andprofile
to catchBrokenPipeError
.bpo-41889: Enum: fix regression involving inheriting a multiply-inherited enum
bpo-41891: Ensure asyncio.wait_for waits for task completion
bpo-41604: Don't decrement the reference count of the previous user_ptr when set_panel_userptr fails.
bpo-40219: Lowered
tkinter.ttk.LabeledScale
dummy widget to prevent hiding part of the content label.bpo-40084: Fix
Enum.__dir__
: dir(Enum.member) now includes attributes as well as methods.bpo-39068: Fix initialization race condition in
a85encode()
andb85encode()
inbase64
. Patch by Brandon Stansbury.bpo-33289: Correct call to
tkinter.colorchooser
to return RGB triplet of ints instead of floats. Patch by Cheryl Sabella.
Documentation¶
bpo-40304: Fix doc for type(name, bases, dict). Patch by Boris Verkhovskiy and Éric Araujo.
bpo-42811: Updated importlib.utils.resolve_name() doc to use __spec__.parent instead of __package__. (Thanks Yair Frid.)
bpo-17140: Add documentation for the
multiprocessing.pool.ThreadPool
class.
Tests¶
Build¶
bpo-43174: Windows build now uses
/utf-8
compiler option.bpo-42692: Fix __builtin_available check on older compilers. Patch by Joshua Root.
bpo-42604: Now all platforms use a value for the "EXT_SUFFIX" build variable derived from SOABI (for instance in freeBSD, "EXT_SUFFIX" is now ".cpython-310d.so" instead of ".so"). Previosuly only Linux, Mac and VxWorks were using a value for "EXT_SUFFIX" that included "SOABI".
bpo-42598: Fix implicit function declarations in configure which could have resulted in incorrect configuration checks. Patch contributed by Joshua Root.
bpo-29076: Add fish shell support to macOS installer.
Windows¶
macOS¶
bpo-42504: Ensure that the value of sysconfig.get_config_var('MACOSX_DEPLOYMENT_TARGET') is always a string, even in when the value is parsable as an integer.
bpo-42361: Update macOS installer build to use Tcl/Tk 8.6.11 (rc2, expected to be final release).
bpo-41837: Update macOS installer build to use OpenSSL 1.1.1i.
bpo-42584: Update macOS installer to use SQLite 3.34.0.
IDLE¶
bpo-43008: Make IDLE invoke
sys.excepthook()
in normal, 2-process mode. Patch by Ken Hilton.bpo-33065: Fix problem debugging user classes with __repr__ method.
bpo-23544: Disable Debug=>Stack Viewer when user code is running or Debugger is active, to prevent hang or crash. Patch by Zackery Spytz.
bpo-32631: Finish zzdummy example extension module: make menu entries work; add docstrings and tests with 100% coverage.
Tools/Demos¶
C API¶
bpo-43030: Fixed a compiler warning in
Py_UNICODE_ISSPACE()
on platforms with signedwchar_t
.bpo-42591: Export the
Py_FrozenMain()
function: fix a Python 3.9.0 regression. Python 3.9 uses-fvisibility=hidden
and the function was not exported explicitly and so not exported.bpo-40052: Fix an alignment build warning/error in function
PyVectorcall_Function()
. Patch by Andreas Schneider, Antoine Pitrou and Petr Viktorin.
Python 3.9.1 final¶
Release date: 2020-12-07
Core and Builtins¶
bpo-42576:
types.GenericAlias
will now raise aTypeError
when attempting to initialize with a keyword argument. Previously, this would cause the interpreter to crash if the interpreter was compiled with debug symbols. This does not affect interpreters compiled for release. Patch by Ken Jin.
Library¶
bpo-5054: CGIHTTPRequestHandler.run_cgi() HTTP_ACCEPT improperly parsed. Replace the special purpose getallmatchingheaders with generic get_all method and add relevant tests.
Original Patch by Martin Panter. Modified by Senthil Kumaran.
bpo-17735:
inspect.findsource()
now raisesOSError
instead ofIndexError
whenco_lineno
of a code object is greater than the file length. This can happen, for example, when a file is edited after it was imported. PR by Irit Katriel.bpo-42116: Fix handling of trailing comments by
inspect.getsource()
.bpo-42487: ChainMap.__iter__ no longer calls __getitem__ on underlying maps
bpo-42482:
TracebackException
no longer holds a reference to the exception's traceback object. Consequently, instances of TracebackException for equivalent but non-equal exceptions now compare as equal.bpo-42406: We fixed an issue in
pickle.whichmodule
in which importingmultiprocessing
could change the how pickle identifies which module an object belongs to, potentially breaking the unpickling of those objects.bpo-34215: Clarify the error message for
asyncio.IncompleteReadError
whenexpected
isNone
.bpo-12800: Extracting a symlink from a tarball should succeed and overwrite the symlink if it already exists. The fix is to remove the existing file or symlink before extraction. Based on patch by Chris AtLee, Jeffrey Kintscher, and Senthil Kumaran.
Tests¶
bpo-41473: Reenable test_gdb on gdb 9.2 and newer: https://bugzilla.redhat.com/show_bug.cgi?id=1866884 bug is fixed in gdb 10.1.
bpo-42553: Fix
test_asyncio.test_call_later()
race condition: don't measure asyncio performance in thecall_later()
unit test. The test failed randomly on the CI.
macOS¶
IDLE¶
bpo-42508: Keep IDLE running on macOS. Remove obsolete workaround that prevented running files with shortcuts when using new universal2 installers built on macOS 11.
Python 3.9.1 release candidate 1¶
Release date: 2020-11-24
Security¶
bpo-42103: Prevented potential DoS attack via CPU and RAM exhaustion when processing malformed Apple Property List files in binary format.
bpo-42051: The
plistlib
module no longer accepts entity declarations in XML plist files to avoid XML vulnerabilities. This should not affect users as entity declarations are not used in regular plist files.bpo-40791: Add
volatile
to the accumulator variable inhmac.compare_digest
, making constant-time-defeating optimizations less likely.
Core and Builtins¶
bpo-41686: On Windows, the
SIGINT
event,_PyOS_SigintEvent()
, is now created even if Python is configured to not install signal handlers (ifPyConfig.install_signal_handlers
equals to 0, orPy_InitializeEx(0)
).bpo-42381: Allow assignment expressions in set literals and set comprehensions as per PEP 572. Patch by Pablo Galindo.
bpo-42374: Fix a regression introduced by the new parser, where an unparenthesized walrus operator was not allowed within generator expressions.
bpo-42296: On Windows, fix a regression in signal handling which prevented to interrupt a program using CTRL+C. The signal handler can be run in a thread different than the Python thread, in which case the test deciding if the thread can handle signals is wrong.
bpo-42332:
types.GenericAlias
objects can now be the targets of weakrefs.bpo-42218: Fixed a bug in the PEG parser that was causing crashes in debug mode. Now errors are checked in left-recursive rules to avoid cases where such errors do not get handled in time and appear as long-distance crashes in other places.
bpo-42214: Fixed a possible crash in the PEG parser when checking for the '!=' token in the
barry_as_flufl
rule. Patch by Pablo Galindo.bpo-42143: Fix handling of errors during creation of
PyFunctionObject
, which resulted in operations on uninitialized memory. Patch by Yonatan Goldschmidt.bpo-41659: Fix a bug in the parser, where a curly brace following a
primary
didn't fail immediately. This led to invalid expressions likea {b}
to throw aSyntaxError
with a wrong offset, or invalid expressions ending with a curly brace likea {
to not fail immediately in the REPL.bpo-42150: Fix possible buffer overflow in the new parser when checking for continuation lines. Patch by Pablo Galindo.
bpo-42123: Run the parser two times. On the first run, disable all the rules that only generate better error messages to gain performance. If there's a parse failure, run the parser a second time with those enabled.
bpo-42057: Fix peephole optimizer misoptimize conditional jump + JUMP_IF_NOT_EXC_MATCH pair.
bpo-41984: The garbage collector now tracks all user-defined classes. Patch by Brandt Bucher.
bpo-41993: Fixed potential issues with removing not completely initialized module from
sys.modules
when import fails.bpo-41979: Star-unpacking is now allowed for with item's targets in the PEG parser.
bpo-41909: Fixed stack overflow in
issubclass()
andisinstance()
when getting the__bases__
attribute leads to infinite recursion.bpo-41894: When loading a native module and a load failure occurs, prevent a possible UnicodeDecodeError when not running in a UTF-8 locale by decoding the load error message using the current locale's encoding.
bpo-39934: Correctly count control blocks in 'except' in compiler. Ensures that a syntax error, rather a fatal error, occurs for deeply nested, named exception handlers.
Library¶
bpo-42328: Fixed
tkinter.ttk.Style.map()
. The function accepts now the representation of the default state as empty sequence (as returned byStyle.map()
). The structure of the result is now the same on all platform and does not depend on the value ofwantobjects
.bpo-42345: Fix various issues with
typing.Literal
parameter handling (flatten, deduplicate, use type to cache key). Patch provided by Yurii Karabas.bpo-42350: Fix the
threading.Thread
class at fork: do nothing if the thread is already stopped (ex: fork called at Python exit). Previously, an error was logged in the child process.bpo-42014: The
onerror
callback fromshutil.rmtree
now receives correct function whenos.open
fails.bpo-42237: Fix
os.sendfile()
on illumos.bpo-42249: Fixed writing binary Plist files larger than 4 GiB.
bpo-35455: On Solaris,
thread_time()
is now implemented withgethrvtime()
becauseclock_gettime(CLOCK_THREAD_CPUTIME_ID)
is not always available. Patch by Jakub Kulik.bpo-42233: The
repr()
oftyping
types containing Generic Alias Types previously did not show the parameterized types in theGenericAlias
. They have now been changed to do so.bpo-41754: webbrowser: Ignore NotADirectoryError when calling
xdg-settings
.bpo-29566:
binhex.binhex()
consistently writes macOS 9 line endings.bpo-42183: Fix a stack overflow error for asyncio Task or Future repr().
The overflow occurs under some circumstances when a Task or Future recursively returns itself.
bpo-42146: Fix memory leak in
subprocess.Popen()
in case an uid (gid) specified inuser
(group
,extra_groups
) overflowsuid_t
(gid_t
).bpo-42140: Improve asyncio.wait function to create the futures set just one time.
bpo-42103:
InvalidFileException
andRecursionError
are now the only errors caused by loading malformed binary Plist file (previously ValueError and TypeError could be raised in some specific cases).bpo-41052: Pickling heap types implemented in C with protocols 0 and 1 raises now an error instead of producing incorrect data.
bpo-41491: plistlib: fix parsing XML plists with hexadecimal integer values
bpo-42065: Fix an incorrectly formatted error from
_codecs.charmap_decode()
when called with a mapped value outside the range of valid Unicode code points. PR by Max Bernstein.bpo-41966: Fix pickling pure Python
datetime.time
subclasses. Patch by Dean Inwood.bpo-41976: Fixed a bug that was causing
ctypes.util.find_library()
to returnNone
when triying to locate a library in an environment when gcc>=9 is available andldconfig
is not. Patch by Pablo Galindobpo-41900: C14N 2.0 serialisation in xml.etree.ElementTree failed for unprefixed attributes when a default namespace was defined.
bpo-41840: Fix a bug in the
symtable
module that was causing module-scope global variables to not be reported as both local and global. Patch by Pablo Galindo.bpo-41831:
str()
for thetype
attribute of thetkinter.Event
object always returns now the numeric code returned by Tk instead of the name of the event type.bpo-41817: fix
tkinter.EventType
Enum so all members are strings, and none are tuplesbpo-41815: Fix SQLite3 segfault when backing up closed database. Patch contributed by Peter David McCormick.
bpo-41316: Fix the
tarfile
module to write only basename of TAR file to GZIP compression header.bpo-16396: Allow
ctypes.wintypes
to be imported on non-Windows systems.bpo-40592:
shutil.which()
now ignores empty entries inPATHEXT
instead of treating them as a match.bpo-40550: Fix time-of-check/time-of-action issue in subprocess.Popen.send_signal.
bpo-40492: Fix
--outfile
forcProfile
/profile
not writing the output file in the original directory when the program being profiled changes the working directory. PR by Anthony Sottile.bpo-40105: ZipFile truncates files to avoid corruption when a shorter comment is provided in append ("a") mode. Patch by Jan Mazur.
bpo-27321: Fixed KeyError exception when flattening an email to a string attempts to replace a non-existent Content-Transfer-Encoding header.
Documentation¶
bpo-42153: Fix the URL for the IMAP protocol documents.
bpo-42061: Document __format__ functionality for IP addresses.
bpo-41910: Document the default implementation of
object.__eq__
.bpo-42010: Clarify that subscription expressions are also valid for certain classes and types in the standard library, and for user-defined classes and types if the classmethod
__class_getitem__()
is provided.bpo-41805: Documented generic alias type and
types.GenericAlias
. Also added an entry in glossary for generic types.bpo-41774: In Programming FAQ "Sequences (Tuples/Lists)" section, add "How do you remove multiple items from a list".
bpo-35293: Fix RemovedInSphinx40Warning when building the documentation. Patch by Dong-hee Na.
bpo-41726: Update the refcounts info of
PyType_FromModuleAndSpec
.bpo-39693: Fix tarfile's extractfile documentation
bpo-39416: Document some restrictions on the default string representations of numeric classes.
Tests¶
bpo-40754: Include
_testinternalcapi
module in Windows installer for test suitebpo-41739: Fix test_logging.test_race_between_set_target_and_flush(): the test now waits until all threads complete to avoid leaking running threads.
bpo-41970: Avoid a test failure in
test_lib2to3
if the module has already imported at the time the test executes. Patch by Pablo Galindo.bpo-41944: Tests for CJK codecs no longer call
eval()
on content received via HTTP.bpo-41939: Fix test_site.test_license_exists_at_url(): call
urllib.request.urlcleanup()
to reset the globalurllib.request._opener
. Patch by Victor Stinner.bpo-41561: test_ssl: skip test_min_max_version_mismatch when TLS 1.0 is not available
bpo-41602: Add tests for SIGINT handling in the runpy module.
bpo-41306: Fixed a failure in
test_tk.test_widgets.ScaleTest
happening when executing the test with Tk 8.6.10.
Build¶
bpo-42398: Fix a race condition in "make regen-all" when make -jN option is used to run jobs in parallel. The clinic.py script now only use atomic write to write files. Moveover, generated files are now left unchanged if the content does not change, to not change the file modification time.
bpo-41617: Fix building
pycore_bitutils.h
internal header on old clang version without__builtin_bswap16()
(ex: Xcode 4.6.3 on Mac OS X 10.7). Patch by Joshua Root and Victor Stinner.bpo-38249: Update
Py_UNREACHABLE
to use __builtin_unreachable() if only the compiler is able to use it. Patch by Dong-hee Na.bpo-40998: Addressed three compiler warnings found by undefined behavior sanitizer (ubsan).
Windows¶
bpo-42120: Remove macro definition of
copysign
(to_copysign
) in headers.bpo-38439: Updates the icons for IDLE in the Windows Store package.
bpo-41744: Fixes automatic import of props file when using the Nuget package.
bpo-41557: Update Windows installer to use SQLite 3.33.0.
bpo-38324: Avoid Unicode errors when accessing certain locale data on Windows.
macOS¶
bpo-41116: Ensure distutils.unixxcompiler.find_library_file can find system provided libraries on macOS 11.
bpo-41100: Add support for macOS 11 and Apple Silicon systems.
It is now possible to build "Universal 2" binaries using "--enable-universalsdk --with-universal-archs=universal2".
Binaries build on later macOS versions can be deployed back to older versions (tested up to macOS 10.9), when using the correct deployment target. This is tested using Xcode 11 and later.
bpo-38443: The
--enable-universalsdk
and--with-universal-archs
options for the configure script now check that the specified architectures can be used.bpo-41471: Ignore invalid prefix lengths in system proxy excludes.
bpo-41557: Update macOS installer to use SQLite 3.33.0.
IDLE¶
bpo-42426: Fix reporting offset of the RE error in searchengine.
bpo-42415: Get docstrings for IDLE calltips more often by using inspect.getdoc.
bpo-33987: Mostly finish using ttk widgets, mainly for editor, settings, and searches. Some patches by Mark Roseman.
bpo-41775: Use 'IDLE Shell' as shell title
bpo-35764: Rewrite the Calltips doc section.
bpo-40181: In calltips, stop reminding that '/' marks the end of positional-only arguments.
bpo-40511: Typing opening and closing parentheses inside the parentheses of a function call will no longer cause unnecessary "flashing" off and on of an existing open call-tip, e.g. when typed in a string literal.
bpo-38439: Add a 256×256 pixel IDLE icon to the Windows .ico file. Created by Andrew Clover. Remove the low-color gif variations from the .ico file.
C API¶
Python 3.9.0 final¶
Release date: 2020-10-04
Library¶
bpo-41815: Fix SQLite3 segfault when backing up closed database. Patch contributed by Peter David McCormick.
bpo-41662: No longer override exceptions raised in
__len__()
of a sequence of parameters insqlite3
withProgrammingError
.bpo-41662: Fixed crash when mutate list of parameters during iteration in
sqlite3
.bpo-39728: fix default
_missing_
so a duplicateValueError
is not set as the__context__
of the originalValueError
Tests¶
bpo-41602: Add tests for SIGINT handling in the runpy module.
Build¶
bpo-38249: Update
Py_UNREACHABLE
to use __builtin_unreachable() if only the compiler is able to use it. Patch by Dong-hee Na.
Python 3.9.0 release candidate 2¶
Release date: 2020-09-16
Core and Builtins¶
bpo-41780: Fix
__dir__()
oftypes.GenericAlias
. Patch by Batuhan Taskaya.bpo-41690: Fix a possible stack overflow in the parser when parsing functions and classes with a huge ammount of arguments. Patch by Pablo Galindo.
bpo-41681: Fixes the wrong error description in the error raised by using 2
,
in format string in f-string andstr.format()
.bpo-41654: Fix a crash that occurred when destroying subclasses of
MemoryError
. Patch by Pablo Galindo.bpo-41631: The
_ast
module uses again a global state. Using a module state per module instance is causing subtle practical problems. For example, the Mercurial project replaces the__import__()
function to implement lazy import, whereas Python expected thatimport _ast
always return a fully initialized_ast
module.bpo-41533: Free the stack allocated in
va_build_stack
ifdo_mkstack
fails and the stack is not asmall_stack
.bpo-41531: Fix a bug that was dropping keys when compiling dict literals with more than 0xFFFF elements. Patch by Pablo Galindo.
bpo-41525: The output of
python --help
contains now only ASCII characters.bpo-29590: Make the stack trace correct after calling
generator.throw()
on a generator that has yielded from ayield from
.
Library¶
bpo-41517: fix bug allowing Enums to be extended via multiple inheritance
bpo-39587: use the correct mix-in data type when constructing Enums
bpo-41789: Honor
object
overrides inEnum
class creation (specifically,__str__
,__repr__
,__format__
, and__reduce_ex__
).bpo-39651: Fix a race condition in the
call_soon_threadsafe()
method ofasyncio.ProactorEventLoop
: do nothing if the self-pipe socket has been closed.bpo-41720: Fixed
turtle.Vec2D.__rmul__()
for arguments which are not int or float.bpo-41696: Fix handling of debug mode in
asyncio.run()
. This allows settingPYTHONASYNCIODEBUG
or-X dev
to enable asyncio debug mode when usingasyncio.run()
.bpo-41687: Fix implementation of sendfile to be compatible with Solaris.
bpo-39010: Restarting a
ProactorEventLoop
on Windows no longer logs spuriousConnectionResetErrors
.bpo-41609: The pdb whatis command correctly reports instance methods as 'Method' rather than 'Function'.
bpo-32751: When cancelling the task due to a timeout,
asyncio.wait_for()
will now wait until the cancellation is complete also in the case when timeout is <= 0, like it does with positive timeouts.bpo-37658:
asyncio.wait_for()
now properly handles races between cancellation of itself and the completion of the wrapped awaitable.bpo-40782: Change the method asyncio.AbstractEventLoop.run_in_executor to not be a coroutine.
bpo-41520: Fix
codeop
regression that prevented turning compile warnings into errors.bpo-41503: Fixed a race between setTarget and flush in logging.handlers.MemoryHandler.
bpo-41344: Prevent creating
shared_memory.SharedMemory
objects withsize=0
.bpo-41025: Fixed an issue preventing the C implementation of
zoneinfo.ZoneInfo
from being subclassed.bpo-31122: ssl.wrap_socket() now raises ssl.SSLEOFError rather than OSError when peer closes connection during TLS negotiation
bpo-33660: Fix pathlib.PosixPath to resolve a relative path located on the root directory properly.
Documentation¶
bpo-37149: Change Shipman tkinter doc link from archive.org to TkDocs. (The doc has been removed from the NMT server.) The new link responds much faster and includes a short explanatory note.
bpo-41624: Fix the signature of
typing.Coroutine
.bpo-40204: Enable Sphinx 3.2
c_allow_pre_v3
option and disablec_warn_on_allowed_pre_v3
option to make the documentation compatible with Sphinx 2 and Sphinx 3.bpo-40979: Refactored typing.rst, arranging more than 70 classes, functions, and decorators into new sub-sections.
bpo-39883: Make code, examples, and recipes in the Python documentation be licensed under the more permissive BSD0 license in addition to the existing Python 2.0 license.
Tests¶
bpo-41731: Make test_cmd_line_script pass with option '-vv'.
Build¶
bpo-41617: Fix
pycore_byteswap.h
header file to support old clang versions:__builtin_bswap16()
is not available in LLVM clang 3.0.
Windows¶
bpo-41526: Fixed layout of final page of the installer by removing the special thanks to Mark Hammond (with his permission).
C API¶
bpo-41524: Fix bug in PyOS_mystrnicmp and PyOS_mystricmp that incremented pointers beyond the end of a string.
Python 3.9.0 release candidate 1¶
Release date: 2020-08-11
Core and Builtins¶
bpo-38156: Handle interrupts that come after EOF correctly in
PyOS_StdioReadline
.
Library¶
bpo-41497: Fix potential UnicodeDecodeError in dis module.
bpo-41490: Update
ensurepip
to install pip 20.2.1 and setuptools 49.2.1.bpo-41467: On Windows, fix asyncio
recv_into()
return value when the socket/pipe is closed (BrokenPipeError
): return0
rather than an empty byte string (b''
).bpo-41425: Make tkinter doc example runnable.
bpo-41384: Raise TclError instead of TypeError when an unknown option is passed to tkinter.OptionMenu.
bpo-38731: Fix
NameError
in command-line interface ofpy_compile
.bpo-41317: Use add_done_callback() in asyncio.loop.sock_accept() to unsubscribe reader early on cancellation.
bpo-41341: Recursive evaluation of
typing.ForwardRef
inget_type_hints
.bpo-41182: selector: use DefaultSelector based upon implementation
bpo-40726: Handle cases where the
end_lineno
isNone
onast.increment_lineno()
.
Documentation¶
Windows¶
bpo-41492: Fixes the description that appears in UAC prompts.
bpo-40948: Improve post-install message to direct people to the "py" command.
bpo-41412: The installer will now fail to install on Windows 7 and Windows 8. Further, the UCRT dependency is now always downloaded on demand.
bpo-40741: Update Windows release to include SQLite 3.32.3.
IDLE¶
Python 3.9.0 beta 5¶
Release date: 2020-07-20
Security¶
bpo-41304: Fixes
python3x._pth
being ignored on Windows, caused by the fix for bpo-29778 (CVE-2020-15801).bpo-41162: Audit hooks are now cleared later during finalization to avoid missing events.
bpo-29778: Ensure
python3.dll
is loaded from correct locations when Python is embedded (CVE-2020-15523).bpo-39603: Prevent http header injection by rejecting control characters in http.client.putrequest(...).
Core and Builtins¶
bpo-41295: Resolve a regression in CPython 3.8.4 where defining "__setattr__" in a multi-inheritance setup and calling up the hierarchy chain could fail if builtins/extension types were involved in the base types.
bpo-41247: Always cache the running loop holder when running
asyncio.set_running_loop
.bpo-41252: Fix incorrect refcounting in _ssl.c's
_servername_callback()
.bpo-41215: Use non-NULL default values in the PEG parser keyword list to overcome a bug that was preventing Python from being properly compiled when using the XLC compiler. Patch by Pablo Galindo.
bpo-41218: Python 3.8.3 had a regression where compiling with ast.PyCF_ALLOW_TOP_LEVEL_AWAIT would aggressively mark list comprehension with CO_COROUTINE. Now only list comprehension making use of async/await will tagged as so.
bpo-41175: Guard against a NULL pointer dereference within bytearrayobject triggered by the
bytearray() + bytearray()
operation.bpo-39960: The "hackcheck" that prevents sneaking around a type's __setattr__() by calling the superclass method was rewritten to allow C implemented heap types.
Library¶
bpo-41288: Unpickling invalid NEWOBJ_EX opcode with the C implementation raises now UnpicklingError instead of crashing.
bpo-39017: Avoid infinite loop when reading specially crafted TAR files using the tarfile module (CVE-2019-20907).
bpo-41235: Fix the error handling in
ssl.SSLContext.load_dh_params()
.bpo-41207: In distutils.spawn, restore expectation that DistutilsExecError is raised when the command is not found.
bpo-39168: Remove the
__new__
method oftyping.Generic
.bpo-41194: Fix a crash in the
_ast
module: it can no longer be loaded more than once. It now uses a global state rather than a module state.bpo-39384: Fixed email.contentmanager to allow set_content() to set a null string.
Documentation¶
bpo-37703: Updated Documentation to comprehensively elaborate on the behaviour of gather.cancel()
macOS¶
bpo-40741: Update macOS installer to use SQLite 3.32.3.
IDLE¶
C API¶
bpo-40170: Revert
PyType_HasFeature()
change: it reads again directly thePyTypeObject.tp_flags
member when the limited C API is not used, rather than always callingPyType_GetFlags()
which hides implementation details.
Python 3.9.0 beta 4¶
Release date: 2020-07-02
Security¶
bpo-41004: The __hash__() methods of ipaddress.IPv4Interface and ipaddress.IPv6Interface incorrectly generated constant hash values of 32 and 128 respectively. This resulted in always causing hash collisions. The fix uses hash() to generate hash values for the tuple of (address, mask length, network address).
Core and Builtins¶
bpo-41094: Fix decoding errors with audit when open files with non-ASCII names on non-UTF-8 locale.
bpo-41084: Prefix the error message with 'f-string: ', when parsing an f-string expression which throws a
SyntaxError
.bpo-41076: Pre-feed the parser with the location of the f-string expression, not the f-string itself, which allows us to skip the shifting of the AST node locations after the parsing is completed.
bpo-40939: Deprecate
PyNode_Compile()
.bpo-41056: Fixes a reference to deallocated stack space during startup when constructing sys.path involving a relative symlink when code was supplied via -c. (discovered via Coverity)
bpo-41061: Fix incorrect expressions and asserts in hashtable code and tests.
bpo-41052: Opt out serialization/deserialization for _random.Random
bpo-40939: Deprecate
PyParser_SimpleParseStringFlags()
,PyParser_SimpleParseStringFlagsFilename()
andPyParser_SimpleParseFileFlags()
.bpo-35975: Stefan Behnel reported that cf_feature_version is used even when PyCF_ONLY_AST is not set. This is against the intention and against the documented behavior, so it's been fixed.
bpo-40985: Fix a bug that caused the
SyntaxError
text to be empty when a file ends with a line ending in a line continuation character (i.e. backslash). The error text should contain the text of the last line.bpo-40958: Fix a possible buffer overflow in the PEG parser when gathering information for emitting syntax errors. Patch by Pablo Galindo.
bpo-40957: Fix refleak in _Py_fopen_obj() when PySys_Audit() fails
bpo-40947: The Python Path Configuration now takes
PyConfig.platlibdir
in account.bpo-40847: Fix a bug where a line with only a line continuation character is not considered a blank line at tokenizer level. In such cases, more than a single
NEWLINE
token was emitted. The old parser was working around the issue, but the new parser threw aSyntaxError
for valid input due to this. For example, an empty line following a line continuation character was interpreted as aSyntaxError
.bpo-40824: Unexpected errors in calling the
__iter__
method are no longer masked byTypeError
in thein
operator and functionscontains()
,indexOf()
andcountOf()
of theoperator
module.bpo-19569: Add the private macros
_Py_COMP_DIAG_PUSH
,_Py_COMP_DIAG_IGNORE_DEPR_DECLS
, and_Py_COMP_DIAG_POP
.
Library¶
bpo-41193: The
write_history()
atexit function of the readline completer now ignores anyOSError
to ignore error if the filesystem is read-only, instead of only ignoringFileNotFoundError
andPermissionError
.bpo-41161: The decimal module now requires libmpdec-2.5.0. Users of --with-system-libmpdec should update their system library.
bpo-40874: The decimal module now requires libmpdec-2.5.0.
bpo-41138: Fixed the
trace
module CLI for Python source files with non-UTF-8 encoding.bpo-31938: Fix default-value signatures of several functions in the
select
module - by Anthony Sottile.bpo-41068: Fixed reading files with non-ASCII names from ZIP archive directly after writing them.
bpo-41058:
pdb.find_function()
now correctly determines the source file encoding.bpo-41056: Fix a NULL pointer dereference within the ssl module during a MemoryError in the keylog callback. (discovered by Coverity)
bpo-41056: Fixed an instance where a MemoryError within the zoneinfo module might not be reported or not reported at its source. (found by Coverity)
bpo-41048:
mimetypes.read_mime_types()
function reads the rule file using UTF-8 encoding, not the locale encoding. Patch by Srinivas Reddy Thatiparthy.bpo-41043: Fixed the use of
glob()
in the stdlib: literal part of the path is now always correctly escaped.bpo-40448:
ensurepip
now disables the use ofpip
cache when installing the bundled versions ofpip
andsetuptools
. Patch by Krzysztof Konopko.bpo-40967: Removed
asyncio.Task.current_task()
andasyncio.Task.all_tasks()
. Patch contributed by Rémi Lapeyre.bpo-40955: Fix a minor memory leak in
subprocess
module when extra_groups was specified.bpo-40855: The standard deviation and variance functions in the statistics module were ignoring their mu and xbar arguments.
bpo-40924: Removed support for loaders implementing .files and supplying TraversableResources.
bpo-40939: Use the new PEG parser when generating the stdlib
keyword
module.bpo-40834: Fix truncate when sending str object with_xxsubinterpreters.channel_send.
bpo-26407: Unexpected errors in calling the
__iter__
method are no longer masked byTypeError
incsv.reader()
,csv.writer.writerow()
andcsv.writer.writerows()
.bpo-38488: Update ensurepip to install pip 20.1.1 and setuptools 47.1.0.
bpo-36543: Restored the deprecated
xml.etree.cElementTree
module.bpo-34226: Fix
cgi.parse_multipart
without content_length. Patch by Roger Duran
Tests¶
bpo-41085: Fix integer overflow in the
array.array.index()
method on 64-bit Windows for index larger than2**31
.bpo-41069:
test.support.TESTFN
and the current directory for tests when run viatest.regrtest
contain now non-ascii characters if possible.bpo-38377: On Linux, skip tests using multiprocessing if the current user cannot create a file in
/dev/shm/
directory. Add theskip_if_broken_multiprocessing_synchronize()
function to thetest.support
module.bpo-41009: Fix use of
support.require_{linux|mac|freebsd}_version()
decorators as class decorator.bpo-41003: Fix
test_copyreg
whennumpy
is installed:test.pickletester
now saves/restores warnings filters when importingnumpy
, to ignore filters installed bynumpy
.bpo-40964: Disable remote
imaplib
tests, host cyrus.andrew.cmu.edu is blocking incoming connections.bpo-40927: Fix test_binhex when run twice: it now uses import_fresh_module() to ensure that it raises DeprecationWarning each time.
bpo-34401: Make test_gdb properly run on HP-UX. Patch by Michael Osipov.
Build¶
bpo-40204: Pin Sphinx version to 2.3.1 in
Doc/Makefile
.
Windows¶
bpo-41074: Fixed support of non-ASCII names in functions
msilib.OpenDatabase()
andmsilib.init_database()
and non-ASCII SQL in methodmsilib.Database.OpenView()
.bpo-40164: Updates Windows OpenSSL to 1.1.1g
bpo-37556: Extend py.exe help to mention overrides via venv, shebang, environmental variables & ini files.
macOS¶
bpo-39580: Avoid opening Finder window if running installer from the command line. Patch contributed by Rick Heil.
bpo-41100: Fix configure error when building on macOS 11. Note that the current Python release was released shortly after the first developer preview of macOS 11 (Big Sur); there are other known issues with building and running on the developer preview. Big Sur is expected to be fully supported in a future bugfix release of Python 3.8.x and with 3.9.0.
bpo-41005: fixed an XDG settings issue not allowing macos to open browser in webbrowser.py
IDLE¶
C API¶
bpo-36346: Mark
Py_UNICODE_COPY
,Py_UNICODE_FILL
,PyUnicode_WSTR_LENGTH
,PyUnicode_FromUnicode
,PyUnicode_AsUnicode
,_PyUnicode_AsUnicode
, andPyUnicode_AsUnicodeAndSize
as deprecated in C. RemovePy_UNICODE_MATCH
which was deprecated and broken since Python 3.3.bpo-36020: On Windows,
#include "pyerrors.h"
no longer definessnprintf
andvsnprintf
macros.bpo-40703: The PyType_FromSpec*() functions no longer overwrite the type's "__module__" attribute if it is set via "Py_tp_members" or "Py_tp_getset".
Python 3.9.0 beta 3¶
Release date: 2020-06-09
Library¶
bpo-40924:
importlib.resources
: RevertedTraversableResources
implementations from the built-in loaders (SourceFileLoader and ZipImporter) as it was an incompatible change introduced in 3.9.0 beta 2 causing through a chain of events for root TLS certificates to be missing.
Build¶
bpo-40684:
make install
now uses thePLATLIBDIR
variable for the destinationlib-dynload/
directory when./configure --with-platlibdir
is used.
Python 3.9.0 beta 2¶
Release date: 2020-06-08
Core and Builtins¶
bpo-40904: Fix possible segfault in the new PEG parser when parsing f-string containing yield statements with no value (
f"{yield}"
). Patch by Pablo Galindobpo-40903: Fixed a possible segfault in the new PEG parser when producing error messages for invalid assignments of the form
p=p=
. Patch by Pablo Galindobpo-40880: Fix invalid memory read in the new parser when checking newlines in string literals. Patch by Pablo Galindo.
bpo-40883: Fix memory leak in when parsing f-strings in the new parser. Patch by Pablo Galindo
bpo-40870: Raise
ValueError
when validating custom AST's where the constantsTrue
,False
andNone
are used within aast.Name
node.bpo-40854: Allow overriding
sys.platlibdir
via a newPYTHONPLATLIBDIR
environment variable.bpo-40826: Fix GIL usage in
PyOS_Readline()
: lock the GIL to set an exception and pass the Python thread state when checking if there is a pending signal.bpo-40780: Fix a corner case where g-style string formatting of a float failed to remove trailing zeros.
bpo-38964: When there's a
SyntaxError
in the expression part of an fstring, the filename attribute of theSyntaxError
gets correctly set to the name of the file the fstring resides in.bpo-40750: Support the "-d" debug flag in the new PEG parser. Patch by Pablo Galindo
bpo-40217: Instances of types created with
PyType_FromSpecWithBases()
will no longer automatically visit their class object when traversing references in the garbage collector. The user is expected to manually visit the object's class. Patch by Pablo Galindo.bpo-40696: Fix a hang that can arise after
generator.throw()
due to a cycle in the exception context chain.
Library¶
bpo-39791: Refresh importlib.metadata from importlib_metadata 1.6.1.
bpo-40807: Stop codeop._maybe_compile, used by code.InteractiveInterpreter (and IDLE). from from emitting each warning three times.
bpo-39791: Built-in loaders (SourceFileLoader and ZipImporter) now supply
TraversableResources
implementations forResourceReader
, and the fallback function has been removed.bpo-17005: The topological sort functionality that was introduced initially in the
functools
module has been moved to a newgraphlib
module to better accommodate the new tools and keep the original scope of thefunctools
module. Patch by Pablo Galindobpo-40777: Initialize PyDateTime_IsoCalendarDateType.tp_base at run-time to avoid errors on some compilers.
bpo-40767:
webbrowser
now properly finds the default browser in pure Wayland systems by checking the WAYLAND_DISPLAY environment variable. Patch contributed by Jérémy Attali.bpo-40791:
hashlib.compare_digest()
uses OpenSSL'sCRYPTO_memcmp()
function when OpenSSL is available.bpo-40795:
ctypes
module: If ctypes fails to convert the result of a callback or if a ctypes callback function raises an exception, sys.unraisablehook is now called with an exception set. Previously, the error was logged into stderr byPyErr_Print()
.bpo-30008: Fix
ssl
code to be compatible with OpenSSL 1.1.x builds that useno-deprecated
and--api=1.1.0
.bpo-30064: Fix asyncio
loop.sock_*
race condition issuebpo-40737: Fix possible reference leak for
sqlite3
initialization.bpo-40698:
distutils
upload creates SHA2-256 and Blake2b-256 digests. MD5 digests is skipped if platform blocks MD5.bpo-40695:
hashlib
no longer falls back to builtin hash implementations when OpenSSL provides a hash digest and the algorithm is blocked by security policy.bpo-9216: func:
hashlib.new
passedusedforsecurity
to OpenSSL EVP constructor_hashlib.new()
. test_hashlib and test_smtplib handle strict security policy better.bpo-40614:
ast.parse()
will not parse self documenting expressions in f-strings when passedfeature_version
is less than(3, 8)
.bpo-40671: Prepare
_hashlib
for PEP 489 and usePyModule_AddType()
.bpo-32309: Added a new coroutine
asyncio.to_thread()
. It is mainly used for running IO-bound functions in a separate thread to avoid blocking the event loop, and essentially works as a high-level version ofrun_in_executor()
that can directly take keyword arguments.bpo-40630: Added
tracemalloc.reset_peak()
to set the peak size of traced memory blocks to the current size, to measure the peak of specific pieces of code.bpo-13097:
ctypes
now raises anArgumentError
when a callback is invoked with more than 1024 arguments.bpo-23082: Updated the error message and docs of PurePath.relative_to() to better reflect the function behaviour.
bpo-39244: Fixed
multiprocessing.context.get_all_start_methods
to properly return the default method first on macOS.bpo-39040: Fix parsing of invalid mime headers parameters by collapsing whitespace between encoded words in a bare-quote-string.
bpo-35714:
struct.error
is now raised if there is a null character in astruct
format string.bpo-36290: AST nodes are now raising
TypeError
on conflicting keyword arguments. Patch contributed by Rémi Lapeyre.
Tests¶
bpo-17258: Skip some
multiprocessing
tests when MD5 hash digest is blocked.
Build¶
Windows¶
macOS¶
bpo-40741: Update macOS installer to use SQLite 3.32.2.
IDLE¶
C API¶
bpo-40910: Export explicitly the
Py_GetArgcArgv()
function to the C API and document the function. Previously, it was exported implicitly which no longer works since Python is built with-fvisibility=hidden
.bpo-40724: Allow defining buffer slots in type specs.
bpo-40826:
PyOS_InterruptOccurred()
now fails with a fatal error if it is called with the GIL released.
Python 3.9.0 beta 1¶
Release date: 2020-05-19
Security¶
Core and Builtins¶
bpo-40663: Correctly generate annotations where parentheses are omitted but required (e.g:
Type[(str, int, *other))]
.bpo-40596: Fixed
str.isidentifier()
for non-canonicalized strings containing non-BMP characters on Windows.bpo-40593: Improved syntax errors for invalid characters in source code.
bpo-40585: Fixed a bug when using
codeop.compile_command()
that was causing exceptions to be swallowed with the new parser. Patch by Pablo Galindobpo-40502: Initialize
n->n_col_offset
. (Patch by Joannah Nanjekye)bpo-40527: Fix command line argument parsing: no longer write errors multiple times into stderr.
bpo-1635741: Port
errno
to multiphase initialization (PEP 489).bpo-40523: Add pass-throughs for
hash()
andreversed()
toweakref.proxy
objects. Patch by Pablo Galindo.bpo-1635741: Port
syslog
to multiphase initialization (PEP 489).bpo-40246: Reporting a specialised error message for invalid string prefixes, which was introduced in bpo-40246, is being reverted due to backwards compatibility concerns for strings that immediately follow a reserved keyword without whitespace between them. Constructs like
bg="#d00" if clear else"#fca"
were failing to parse, which is not an acceptable breakage on such short notice.bpo-40417: Fix imp module deprecation warning when PyImport_ReloadModule is called. Patch by Robert Rouhani.
bpo-40408: Fixed support of nested type variables in GenericAlias (e.g.
list[list[T]]
).bpo-1635741: Port _stat module to multiphase initialization (PEP 489).
bpo-29587: Enable implicit exception chaining when calling
generator.throw()
.bpo-40328: Add tools for generating mappings headers for CJKCodecs.
bpo-40228: Setting frame.f_lineno is now robust w.r.t. changes in the source-to-bytecode compiler
bpo-38880: Added the ability to list interpreters associated with channel ends in the internal subinterpreters module.
bpo-37986: Improve performance of
PyLong_FromDouble()
for values that fit intolong
.
Library¶
bpo-40662: Fixed
ast.get_source_segment()
for ast nodes that have incomplete location information. Patch by Irit Katriel.bpo-40536: Added the
available_timezones()
function to thezoneinfo
module. Patch by Paul Ganssle.bpo-40645: The
hmac.HMAC
exposes internal implementation details. The attributesdigest_cons
,inner
, andouter
are deprecated and will be removed in the future.bpo-40645: The internal module
_hashlib
wraps and exposes OpenSSL's HMAC API. The new code will be used in Python 3.10 after the internal implementation details of the pure Python HMAC module are no longer part of the public API.bpo-40637: Builtin hash modules can now be disabled or selectively enabled with
configure --with-builtin-hashlib-hashes=sha3,blake1
or--without-builtin-hashlib-hashes
.bpo-37630: The
hashlib
module can now use SHA3 hashes and SHAKE XOF from OpenSSL when available.bpo-40479: The
hashlib
now compiles with OpenSSL 3.0.0-alpha2.bpo-40257: Revert changes to
inspect.getdoc()
.bpo-40607: When cancelling a task due to timeout,
asyncio.wait_for()
will now propagate the exception if an error happens during cancellation. Patch by Roman Skurikhin.bpo-40612: Fix edge cases in SyntaxError formatting. If the offset is <= 0, no caret is printed. If the offset is > line length, the caret is printed pointing just after the last character.
bpo-40597: If text content lines are longer than policy.max_line_length, always use a content-encoding to make sure they are wrapped.
bpo-40571: Added functools.cache() as a simpler, more discoverable way to access the unbounded cache variant of lru_cache(maxsize=None).
bpo-40503: PEP 615, the
zoneinfo
module. Adds support for the IANA time zone database.bpo-40397: Removed attributes
__args__
and__parameters__
from special generic aliases liketyping.List
(not subscripted).bpo-40549: Convert posixmodule.c ("posix" or "nt" module) to the multiphase initialization (PEP 489).
bpo-31033: Add a
msg
argument toFuture.cancel()
andTask.cancel()
.bpo-40541: Added an optional counts parameter to random.sample().
bpo-40515: The
ssl
andhashlib
modules now actively check that OpenSSL is build with thread support. Python 3.7.0 made thread support mandatory and no longer works safely with a no-thread builds.bpo-31033: When a
asyncio.Task
is cancelled, the exception traceback now chains all the way back to where the task was first interrupted.bpo-40504:
functools.lru_cache()
objects can now be the targets of weakrefs.bpo-40559: Fix possible memory leak in the C implementation of
asyncio.Task
.bpo-40480:
fnmatch.fnmatch()
could take exponential time in the presence of multiple*
pattern characters. This was repaired by generating more elaborate regular expressions to avoid futile backtracking.bpo-40495:
compileall
is now able to use hardlinks to prevent duplicates in a case when.pyc
files for different optimization levels have the same content.bpo-40457: The ssl module now support OpenSSL builds without TLS 1.0 and 1.1 methods.
bpo-40355: Improve error reporting in
ast.literal_eval()
in the presence of malformedast.Dict
nodes instead of silently ignoring any non-conforming elements. Patch by Curtis Bucher.bpo-40465: Deprecated the optional random argument to random.shuffle().
bpo-40459:
platform.win32_ver()
now produces correct ptype strings instead of empty strings.bpo-39435: The first argument of
pickle.loads()
is now positional-only.bpo-39305: Update
nntplib
to mergenntplib.NNTP
andnntplib._NNTPBase
. Patch by Dong-hee Na.bpo-32494: Update
dbm.gnu
to use gdbm_count if possible when callinglen()
. Patch by Dong-hee Na.bpo-40453: Add
isolated=True
keyword-only parameter to_xxsubinterpreters.create()
. An isolated subinterpreter cannot spawn threads, spawn a child process or callos.fork()
.bpo-40286: Remove
_random.Random.randbytes()
: the C implementation ofrandbytes()
. Implement the method in Python to ease subclassing:randbytes()
now directly reusesgetrandbits()
.bpo-40394: Added default arguments to
difflib.SequenceMatcher.find_longest_match()
.bpo-39995: Fix a race condition in concurrent.futures._ThreadWakeup: access to _ThreadWakeup is now protected with the shutdown lock.
bpo-30966:
Process.shutdown(wait=True)
ofconcurrent.futures
now closes explicitly the result queue.bpo-30966: Add a new
close()
method to theSimpleQueue
class to explicitly close the queue.bpo-39966: Revert bpo-25597.
unittest.mock.MagicMock
with wraps' set uses default return values for magic methods.bpo-39791: Added
files()
function to importlib.resources with support for subdirectories in package data, matching backport in importlib_resources 1.5.bpo-40375:
imaplib.IMAP4.unselect()
is added. Patch by Dong-hee Na.bpo-40389:
repr()
now returnstyping.Optional[T]
when called fortyping.Union
of two types, one of which isNoneType
.bpo-40291: Add support for CAN_J1939 sockets (available on Linux 5.4+)
bpo-40273:
types.MappingProxyType
is now reversible.bpo-39075: The repr for
types.SimpleNamespace
is now insertion ordered rather than alphabetical.bpo-40192: On AIX,
thread_time()
is now implemented withthread_cputime()
which has nanosecond resolution, rather thanclock_gettime(CLOCK_THREAD_CPUTIME_ID)
which has a resolution of 10 ms. Patch by Batuhan Taskaya.bpo-40025: Raise TypeError when _generate_next_value_ is defined after members. Patch by Ethan Onstott.
bpo-39058: In the argparse module, the repr for Namespace() and other argument holders now displayed in the order attributes were added. Formerly, it displayed in alphabetical order even though argument order is preserved the user visible parts of the module.
bpo-24416: The
isocalendar()
methods ofdatetime.date
anddatetime.datetime
now return a named tuple instead of atuple
.
Documentation¶
bpo-34790: Add version of removal for explicit passing of coros to
asyncio.wait()
's documentationbpo-40561: Provide docstrings for webbrowser open functions.
bpo-40499: Mention that
asyncio.wait()
requires a non-empty set of awaitables.bpo-39705: Tutorial example for sorted() in the Loop Techniques section is given a better explanation. Also a new example is included to explain sorted()'s basic behavior.
bpo-39435: Fix an incorrect signature for
pickle.loads()
in the docs
Tests¶
Build¶
Windows¶
bpo-40650: Include winsock2.h in pytime.c for timeval.
bpo-40458: Increase reserved stack space to prevent overflow crash on Windows.
bpo-39148: Add IPv6 support to
asyncio
datagram endpoints in ProactorEventLoop. Change the raised exception for unknown address families to ValueError as it's not coming from Windows API.
macOS¶
bpo-34956: When building Python on macOS from source,
_tkinter
now links with non-system Tcl and Tk frameworks if they are installed in/Library/Frameworks
, as had been the case on older releases of macOS. If a macOS SDK is explicitly configured, by using--enable-universalsdk=
or-isysroot
, only the SDK itself is searched. The default behavior can still be overridden with--with-tcltk-includes
and--with-tcltk-libs
.bpo-35569: Expose RFC 3542 IPv6 socket options.
Tools/Demos¶
bpo-40479: Update multissltest helper to test with latest OpenSSL 1.0.2, 1.1.0, 1.1.1, and 3.0.0-alpha.
bpo-40431: Fix a syntax typo in
turtledemo
that now raises aSyntaxError
.bpo-40163: Fix multissltest tool. OpenSSL has changed download URL for old releases. The multissltest tool now tries to download from current and old download URLs.
C API¶
bpo-39465: Remove the
_PyUnicode_ClearStaticStrings()
function from the C API.bpo-38787: Add PyCFunction_CheckExact() macro for exact type checks now that we allow subtypes of PyCFunction, as well as PyCMethod_CheckExact() and PyCMethod_Check() for the new PyCMethod subtype.
bpo-40545: Declare
_PyErr_GetTopmostException()
withPyAPI_FUNC()
to properly export the function in the C API. The function remains private (_Py
) prefix.bpo-40412: Nullify inittab_copy during finalization, preventing future interpreter initializations in an embedded situation from crashing. Patch by Gregory Szorc.
bpo-40429: The
PyThreadState_GetFrame()
function now returns a strong reference to the frame.bpo-40428: Remove the following functions from the C API. Call
PyGC_Collect()
explicitly to free all free lists.PyAsyncGen_ClearFreeLists()
PyContext_ClearFreeList()
PyDict_ClearFreeList()
PyFloat_ClearFreeList()
PyFrame_ClearFreeList()
PyList_ClearFreeList()
PySet_ClearFreeList()
PyTuple_ClearFreeList()
bpo-40421: New
PyFrame_GetBack()
function: get the frame next outer frame.bpo-40421: New
PyFrame_GetCode()
function: return a borrowed reference to the frame code.bpo-40217: Ensure that instances of types created with
PyType_FromSpecWithBases()
will visit its class object when traversing references in the garbage collector (implemented as an extension of the providedtp_traverse
). Patch by Pablo Galindo.bpo-38787: Module C state is now accessible from C-defined heap type methods (PEP 573). Patch by Marcel Plch and Petr Viktorin.
Python 3.9.0 alpha 6¶
Release date: 2020-04-27
Security¶
bpo-40121: Fixes audit events raised on creating a new socket.
bpo-39073: Disallow CR or LF in email.headerregistry.Address arguments to guard against header injection attacks.
bpo-39503: CVE-2020-8492: The
AbstractBasicAuthHandler
class of theurllib.request
module uses an inefficient regular expression which can be exploited by an attacker to cause a denial of service. Fix the regex to prevent the catastrophic backtracking. Vulnerability reported by Ben Caller and Matt Schwager.
Core and Builtins¶
bpo-40313: Improve the performance of bytes.hex().
bpo-40334: Switch to a new parser, based on PEG. For more details see PEP 617. To temporarily switch back to the old parser, use
-X oldparser
orPYTHONOLDPARSER=1
. In Python 3.10 we will remove the old parser completely, including theparser
module (already deprecated) and anything that depends on it.bpo-40267: Fix the tokenizer to display the correct error message, when there is a SyntaxError on the last input character and no newline follows. It used to be
unexpected EOF while parsing
, while it should beinvalid syntax
.bpo-39522: Correctly unparse explicit
u
prefix for strings when postponed evaluation for annotations activated. Patch by Batuhan Taskaya.bpo-40246: Report a specialized error message,
invalid string prefix
, when the tokenizer encounters a string with an invalid prefix.bpo-40082: Fix the signal handler: it now always uses the main interpreter, rather than trying to get the current Python thread state.
bpo-37388: str.encode() and str.decode() no longer check the encoding and errors in development mode or in debug mode during Python finalization. The codecs machinery can no longer work on very late calls to str.encode() and str.decode().
bpo-40077: Fix possible refleaks in
_json
, memo of PyScannerObject should be traversed.bpo-37207: Speed up calls to
dict()
by using the PEP 590vectorcall
calling convention.bpo-40141: Add column and line information to
ast.keyword
nodes. Patch by Pablo Galindo.bpo-1635741: Port
resource
to multiphase initialization (PEP 489).bpo-1635741: Port
math
to multiphase initialization (PEP 489).bpo-1635741: Port _uuid module to multiphase initialization (PEP 489).
bpo-40077: Convert json module to use
PyType_FromSpec()
.bpo-40067: Improve the error message for multiple star expressions in an assignment. Patch by Furkan Onder
bpo-1635741: Port _functools module to multiphase initialization (PEP 489). Patch by Paulo Henrique Silva.
bpo-1635741: Port operator module to multiphase initialization (PEP 489). Patch by Paulo Henrique Silva.
bpo-20526: Fix
PyThreadState_Clear()
.PyThreadState.frame
is a borrowed reference, not a strong reference:PyThreadState_Clear()
must not callPy_CLEAR(tstate->frame)
.bpo-1635741: Port time module to multiphase initialization (PEP 489). Patch by Paulo Henrique Silva.
bpo-1635741: Port _weakref extension module to multiphase initialization (PEP 489).
bpo-40020: Fix a leak and subsequent crash in parsetok.c caused by realloc misuse on a rare codepath.
bpo-39939: Added str.removeprefix and str.removesuffix methods and corresponding bytes, bytearray, and collections.UserString methods to remove affixes from a string if present. See PEP 616 for a full description. Patch by Dennis Sweeney.
bpo-39481: Implement PEP 585. This supports list[int], tuple[str, ...] etc.
bpo-32894: Support unparsing of infinity numbers in postponed annotations. Patch by Batuhan Taşkaya.
bpo-37207: Speed up calls to
list()
by using the PEP 590vectorcall
calling convention. Patch by Mark Shannon.
Library¶
bpo-40398:
typing.get_args()
now always returns an empty tuple for special generic aliases.bpo-40396: Functions
typing.get_origin()
,typing.get_args()
andtyping.get_type_hints()
support now generic aliases likelist[int]
.bpo-38061: Optimize the
subprocess
module on FreeBSD usingclosefrom()
. A singleclose(fd)
syscall is cheap, but whensysconf(_SC_OPEN_MAX)
is high, the loop callingclose(fd)
on each file descriptor can take several milliseconds.The workaround on FreeBSD to improve performance was to load and mount the fdescfs kernel module, but this is not enabled by default.
Initial patch by Ed Maste (emaste), Conrad Meyer (cem), Kyle Evans (kevans) and Kubilay Kocak (koobs): https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=242274
bpo-38061: On FreeBSD,
os.closerange(fd_low, fd_high)
now callsclosefrom(fd_low)
if fd_high is greater than or equal tosysconf(_SC_OPEN_MAX)
.Initial patch by Ed Maste (emaste), Conrad Meyer (cem), Kyle Evans (kevans) and Kubilay Kocak (koobs): https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=242274
bpo-40360: The
lib2to3
module is pending deprecation due to PEP 617.bpo-40138: Fix the Windows implementation of
os.waitpid()
for exit code larger thanINT_MAX >> 8
. The exit status is now interpreted as an unsigned number.bpo-39942: Set "__main__" as the default module name when "__name__" is missing in
typing.TypeVar
. Patch by Weipeng Hong.bpo-40275: The
logging
package is now imported lazily inunittest
only when theassertLogs()
assertion is used.bpo-40275: The
asyncio
package is now imported lazily inunittest
only when theIsolatedAsyncioTestCase
class is used.bpo-40330: In
ShareableList.__setitem__()
, check the size of a new string item after encoding it to utf-8, not before.bpo-40148: Added
pathlib.Path.with_stem()
to create a new Path with the stem replaced.bpo-40325: Deprecated support for set objects in random.sample().
bpo-40257: Improved help for the
typing
module. Docstrings are now shown for all special forms and special generic aliases (likeUnion
andList
). Usinghelp()
with generic alias likeList[int]
will show the help for the correspondent concrete type (list
in this case).bpo-40257: func:
inspect.getdoc
no longer returns docstring inherited from the type of the object or from parent class if it is a class if it is not defined in the object itself. Inpydoc
the documentation string is now shown not only for class, function, method etc, but for any object that has its own__doc__
attribute.bpo-40287: Fixed
SpooledTemporaryFile.seek()
to return the position.bpo-40290: Added zscore() to statistics.NormalDist().
bpo-40282: Allow
random.getrandbits(0)
to succeed and to return 0.bpo-40286: Add
random.randbytes()
function andrandom.Random.randbytes()
method to generate random bytes.bpo-40277:
collections.namedtuple()
now provides a human-readable repr for its field accessors.bpo-40270: The included copy of sqlite3 on Windows is now compiled with the json extension. This allows the use of functions such as
json_object
.bpo-29255: Wait in
KqueueSelector.select
when no fds are registeredbpo-40260: Ensure
modulefinder
usesio.open_code()
and respects coding comments.bpo-40234: Allow again to spawn daemon threads in subinterpreters (revert change which denied them).
bpo-39207: Workers in
ProcessPoolExecutor
are now spawned on demand, only when there are no available idle workers to reuse. This optimizes startup overhead and reduces the amount of lost CPU time to idle workers. Patch by Kyle Stanley.bpo-40091: Fix a hang at fork in the logging module: the new private _at_fork_reinit() method is now used to reinitialize locks at fork in the child process.
bpo-40149: Implement traverse and clear slots in _abc._abc_data type.
bpo-40208: Remove deprecated
symtable.SymbolTable.has_exec()
.bpo-40196: Fix a bug in the
symtable
module that was causing incorrectly report global variables as local. Patch by Pablo Galindo.bpo-40190: Add support for
_SC_AIX_REALMEM
toposix.sysconf()
.bpo-40182: Removed the
_field_types
attribute of thetyping.NamedTuple
class.bpo-36517: Multiple inheritance with
typing.NamedTuple
now raises an error instead of silently ignoring other types.bpo-40126: Fixed reverting multiple patches in unittest.mock. Patcher's
__exit__()
is now never called if its__enter__()
is failed. Returning true from__exit__()
silences now the exception.bpo-40094: CGIHTTPRequestHandler of http.server now logs the CGI script exit code, rather than the CGI script exit status of os.waitpid(). For example, if the script is killed by signal 11, it now logs: "CGI script exit code -11."
bpo-40108: Improve the error message when triying to import a module using
runpy
and incorrently use the ".py" extension at the end of the module name. Patch by Pablo Galindo.bpo-40094: Add
os.waitstatus_to_exitcode()
function: convert a wait status to an exit code.bpo-40089: Fix threading._after_fork(): if fork was not called by a thread spawned by threading.Thread, threading._after_fork() now creates a _MainThread instance for _main_thread, instead of a _DummyThread instance.
bpo-40089: Add a private
_at_fork_reinit()
method to_thread.Lock
,_thread.RLock
,threading.RLock
andthreading.Condition
classes: reinitialize the lock at fork in the child process, reset the lock to the unlocked state. Rename also the private_reset_internal_locks()
method ofthreading.Event
to_at_fork_reinit()
.bpo-25780: Expose
CAN_RAW_JOIN_FILTERS
in thesocket
module.bpo-39503:
AbstractBasicAuthHandler
ofurllib.request
now parses all WWW-Authenticate HTTP headers and accepts multiple challenges per header: use the realm of the first Basic challenge.bpo-39812: Removed daemon threads from
concurrent.futures
by adding an internalthreading._register_atexit()
, which calls registered functions prior to joining all non-daemon threads. This allows for compatibility with subinterpreters, which don't support daemon threads.bpo-40050: Fix
importlib._bootstrap_external
: avoid creating a newwinreg
builtin module if it's already available insys.modules
, and remove redundant imports.bpo-40014: Fix
os.getgrouplist()
: ifgetgrouplist()
function fails because the group list is too small, retry with a larger group list. On failure, the glibc implementation ofgetgrouplist()
setsngroups
to the total number of groups. For other implementations, double the group list size.bpo-40017: Add
time.CLOCK_TAI
constant if the operating system support it.bpo-40016: In re docstring, clarify the relationship between inline and argument compile flags.
bpo-39953: Update internal table of OpenSSL error codes in the
ssl
module.bpo-36144: Added PEP 584 operators to
weakref.WeakValueDictionary
.bpo-36144: Added PEP 584 operators to
weakref.WeakKeyDictionary
.bpo-38891: Fix linear runtime behaviour of the
__getitem__
and__setitem__
methods inmultiprocessing.shared_memory.ShareableList
. This avoids quadratic performance when iterating aShareableList
. Patch by Thomas Krennwallner.bpo-39682: Remove undocumented support for closing a
pathlib.Path
object via its context manager. The context manager magic methods remain, but they are now a no-op, makingPath
objects immutable.bpo-36144: Added PEP 584 operators (
|
and|=
) tocollections.ChainMap
.bpo-39011: Normalization of line endings in ElementTree attributes was removed, as line endings which were replaced by entity numbers should be preserved in original form.
bpo-38410: Properly handle
sys.audit()
failures insys.set_asyncgen_hooks()
.bpo-36541: lib2to3 now recognizes named assignment expressions (the walrus operator,
:=
)bpo-35967: In platform, delay the invocation of 'uname -p' until the processor attribute is requested.
bpo-35113:
inspect.getsource()
now returns correct source code for inner class with same name as module level class. Decorators are also returned as part of source of the class. Patch by Karthikeyan Singaravelan.bpo-33262: Deprecate passing None as an argument for
shlex.split()
'ss
parameter. Patch by Zackery Spytz.bpo-31758: Prevent crashes when using an uninitialized
_elementtree.XMLParser
object. Patch by Oren Milman.
Documentation¶
bpo-27635: The pickle documentation incorrectly claimed that
__new__
isn't called by default when unpickling.bpo-39879: Updated Modèle de données docs to include
dict()
insertion order preservation. Patch by Furkan Onder and Samy Lahfa.bpo-38387: Document
PyDoc_STRVAR
macro in the C-API reference.bpo-13743: Some methods within xml.dom.minidom.Element class are now better documented.
Tests¶
bpo-31904: Set expected default encoding in test_c_locale_coercion.py for VxWorks RTOS.
bpo-40162: Update Travis CI configuration to OpenSSL 1.1.1f.
bpo-40146: Update OpenSSL to 1.1.1f in Azure Pipelines.
bpo-40094: Add
test.support.wait_process()
function.bpo-40003:
test.bisect_cmd
now copies Python command line options like-O
or-W
. Moreover, emit a warning iftest.bisect_cmd
is used with-w
/--verbose2
option.bpo-39380: Add the encoding in
ftplib.FTP
andftplib.FTP_TLS
to the constructor as keyword-only and change the default fromlatin-1
toutf-8
to follow RFC 2640.bpo-39793: Use the same domain when testing
make_msgid
. Patch by Batuhan Taskaya.bpo-1812: Fix newline handling in doctest.testfile when loading from a package whose loader has a get_data method. Patch by Peter Donis.
Build¶
bpo-38360: Support single-argument form of macOS -isysroot flag.
bpo-40158: Fix CPython MSBuild Properties in NuGet Package (build/native/python.props)
bpo-38527: Fix configure check on Solaris for "float word ordering": sometimes, the correct "grep" command was not being used. Patch by Arnon Yaari.
Windows¶
macOS¶
bpo-38329: python.org macOS installers now update the Current version symlink of /Library/Frameworks/Python.framework/Versions for 3.9 installs. Previously, Current was only updated for Python 2.x installs. This should make it easier to embed Python 3 into other macOS applications.
bpo-40164: Update macOS installer builds to use OpenSSL 1.1.1g.
IDLE¶
Tools/Demos¶
bpo-40385: Removed the checkpyc.py tool. Please see compileall without force mode as a potential alternative.
bpo-40179: Fixed translation of
#elif
in Argument Clinic.bpo-40094: Fix
which.py
script exit code: it now usesos.waitstatus_to_exitcode()
to convertos.system()
exit status into an exit code.
C API¶
bpo-40241: Move the
PyGC_Head
structure to the internal C API.bpo-40170: Convert
PyObject_IS_GC()
macro to a function to hide implementation details.bpo-40241: Add the functions
PyObject_GC_IsTracked()
andPyObject_GC_IsFinalized()
to the public API to allow to query if Python objects are being currently tracked or have been already finalized by the garbage collector respectively. Patch by Pablo Galindo.bpo-40170: The
PyObject_NEW()
macro becomes an alias to thePyObject_New()
macro, and thePyObject_NEW_VAR()
macro becomes an alias to thePyObject_NewVar()
macro, to hide implementation details. They no longer access directly thePyTypeObject.tp_basicsize
member.bpo-40170:
PyType_HasFeature()
now always callsPyType_GetFlags()
to hide implementation details. Previously, it accessed directly thePyTypeObject.tp_flags
member when the limited C API was not used.bpo-40170: Convert the
PyObject_GET_WEAKREFS_LISTPTR()
macro to a function to hide implementation details: the macro accessed directly to thePyTypeObject.tp_weaklistoffset
member.bpo-40170: Convert
PyObject_CheckBuffer()
macro to a function to hide implementation details: the macro accessed directly thePyTypeObject.tp_as_buffer
member.bpo-40170: Always declare
PyIndex_Check()
as an opaque function to hide implementation details: removePyIndex_Check()
macro. The macro accessed directly thePyTypeObject.tp_as_number
member.bpo-39947: Add
PyThreadState_GetID()
function: get the unique identifier of a Python thread state.
Python 3.9.0 alpha 5¶
Release date: 2020-03-23
Security¶
bpo-38576: Disallow control characters in hostnames in http.client, addressing CVE-2019-18348. Such potentially malicious header injection URLs now cause a InvalidURL to be raised.
Core and Builtins¶
bpo-40010: Optimize pending calls in multithreaded applications. If a thread different than the main thread schedules a pending call (
Py_AddPendingCall()
), the bytecode evaluation loop is no longer interrupted at each bytecode instruction to check for pending calls which cannot be executed. Only the main thread can execute pending calls.Previously, the bytecode evaluation loop was interrupted at each instruction until the main thread executes pending calls.
bpo-1635741: Port _weakref extension module to multiphase initialization (PEP 489).
bpo-1635741: Port _collections module to multiphase initialization (PEP 489).
bpo-40010: Optimize signal handling in multithreaded applications. If a thread different than the main thread gets a signal, the bytecode evaluation loop is no longer interrupted at each bytecode instruction to check for pending signals which cannot be handled. Only the main thread of the main interpreter can handle signals.
Previously, the bytecode evaluation loop was interrupted at each instruction until the main thread handles signals.
bpo-39984: If
Py_AddPendingCall()
is called in a subinterpreter, the function is now scheduled to be called from the subinterpreter, rather than being called from the main interpreter. Each subinterpreter now has its own list of scheduled calls.bpo-1635741: Port _heapq module to multiphase initialization.
bpo-1635741: Port itertools module to multiphase initialization (PEP 489).
bpo-37207: Speed up calls to
frozenset()
by using the PEP 590vectorcall
calling convention. Patch by Dong-hee Na.bpo-39984: subinterpreters: Move
_PyRuntimeState.ceval.tracing_possible
toPyInterpreterState.ceval.tracing_possible
: each interpreter now has its own variable.bpo-37207: Speed up calls to
set()
by using the PEP 590vectorcall
calling convention. Patch by Dong-hee Na.bpo-1635741: Port _statistics module to multiphase initialization (PEP 489).
bpo-39968: Use inline function to replace extension modules' get_module_state macros.
bpo-39965: Correctly raise
SyntaxError
if await is used inside non-async functions andPyCF_ALLOW_TOP_LEVEL_AWAIT
is set (like in the asyncio REPL). Patch by Pablo Galindo.bpo-39562: Allow executing asynchronous comprehensions on the top level when the
PyCF_ALLOW_TOP_LEVEL_AWAIT
flag is given. Patch by Batuhan Taskaya.bpo-37207: Speed up calls to
tuple()
by using the PEP 590vectorcall
calling convention. Patch by Dong-hee Na.bpo-38373: Changed list overallocation strategy. It no longer overallocates if the new size is closer to overalocated size than to the old size and adds padding.
bpo-39926: Update Unicode database to Unicode version 13.0.0.
bpo-19466: Clear the frames of daemon threads earlier during the Python shutdown to call objects destructors. So "unclosed file" resource warnings are now emitted for daemon threads in a more reliable way.
bpo-38894: Fix a bug that was causing incomplete results when calling
pathlib.Path.glob
in the presence of symlinks that point to files where the user does not have read access. Patch by Pablo Galindo and Matt Wozniski.bpo-39877: Fix
PyEval_RestoreThread()
random crash at exit with daemon threads. It now accesses the_PyRuntime
variable directly instead of usingtstate->interp->runtime
, sincetstate
can be a dangling pointer afterPy_Finalize()
has been called. Moreover, the daemon thread now exits before trying to take the GIL.bpo-39871: Fix a possible
SystemError
inmath.{atan2,copysign,remainder}()
when the first argument cannot be converted to afloat
. Patch by Zackery Spytz.bpo-39776: Fix race condition where threads created by PyGILState_Ensure() could get a duplicate id.
This affects consumers of tstate->id like the contextvar caching machinery, which could return invalid cached objects under heavy thread load (observed in embedded scenarios).
bpo-39778: Fixed a crash due to incorrect handling of weak references in
collections.OrderedDict
classes. Patch by Pablo Galindo.bpo-1635741: Port audioop extension module to multiphase initialization (PEP 489).
bpo-39702: Relax decorator grammar restrictions to allow any valid expression (PEP 614).
bpo-38091: Tweak import deadlock detection code to not deadlock itself.
bpo-1635741: Port _locale extension module to multiphase initialization (PEP 489).
bpo-39087: Optimize
PyUnicode_AsUTF8()
andPyUnicode_AsUTF8AndSize()
slightly when they need to create internal UTF-8 cache.bpo-39520: Fix unparsing of ext slices with no items (
foo[:,]
). Patch by Batuhan Taskaya.bpo-39220: Do not optimize annotations if 'from __future__ import annotations' is used. Patch by Pablo Galindo.
bpo-35712: Using
NotImplemented
in a boolean context has been deprecated. Patch contributed by Josh Rosenberg.bpo-22490: Don't leak environment variable
__PYVENV_LAUNCHER__
into the interpreter session on macOS.
Library¶
bpo-39830: Add
zipfile.Path
to__all__
in thezipfile
module.bpo-40000: Improved error messages for validation of
ast.Constant
nodes. Patch by Batuhan Taskaya.bpo-39999:
__module__
of the AST node classes is now set to "ast" instead of "_ast". Added docstrings for dummy AST node classes and deprecated attributes.bpo-39991:
uuid.getnode()
now skips IPv6 addresses with the same string length than a MAC address (17 characters): only use MAC addresses.bpo-39988: Deprecated
ast.AugLoad
andast.AugStore
node classes because they are no longer used.bpo-39656: Ensure
bin/python3.#
is always present in virtual environments on POSIX platforms - by Anthony Sottile.bpo-39969: Deprecated
ast.Param
node class because it's no longer used. Patch by Batuhan Taskaya.bpo-39360: Ensure all workers exit when finalizing a
multiprocessing.Pool
implicitly via the module finalization handlers of multiprocessing. This fixes a deadlock situation that can be experienced when the Pool is not properly finalized via the context manager or a call tomultiprocessing.Pool.terminate
. Patch by Batuhan Taskaya and Pablo Galindo.bpo-35370: sys.settrace(), sys.setprofile() and _lsprof.Profiler.enable() now properly report
PySys_Audit()
error if "sys.setprofile" or "sys.settrace" audit event is denied.bpo-39936: AIX: Fix _aix_support module when the subprocess is not available, when building Python from scratch. It now uses new private _bootsubprocess module, rather than having two implementations depending if subprocess is available or not. So _aix_support.aix_platform() result is now the same if subprocess is available or not.
bpo-36144:
collections.OrderedDict
now implements|
and|=
(PEP 584).bpo-39652: The column name found in
sqlite3.Cursor.description
is now truncated on the first '[' only if the PARSE_COLNAMES option is set.bpo-39915: Ensure
unittest.mock.AsyncMock.await_args_list
has call objects in the order of awaited arguments instead of usingunittest.mock.Mock.call_args
which has the last value of the call. Patch by Karthikeyan Singaravelan.bpo-36144: Updated
os.environ
andos.environb
to support PEP 584's merge (|
) and update (|=
) operators.bpo-38662: The
ensurepip
module now invokespip
via therunpy
module. Hence it is no longer tightly coupled with the internal API of the bundledpip
version, allowing easier updates to a newerpip
version both internally and for distributors.bpo-38075: Fix the
random.Random.seed()
method when abool
is passed as the seed.bpo-39916: More reliable use of
os.scandir()
inPath.glob()
. It no longer emits a ResourceWarning when interrupted.bpo-39850:
multiprocessing
now supports abstract socket addresses (if abstract sockets are supported in the running platform). When creating arbitrary addresses (like when default-constructingmultiprocessing.connection.Listener
objects) abstract sockets are preferred to avoid the case when the temporary-file-generated address is too large for an AF_UNIX socket address. Patch by Pablo Galindo.bpo-36287:
ast.dump()
no longer outputs optional fields and attributes with default values. The default values for optional fields and attributes of AST nodes are now set as class attributes (e.g.Constant.kind
is set toNone
).bpo-39889: Fixed
ast.unparse()
for extended slices containing a single element (e.g.a[i:j,]
). Remove redundant tuples when index with a tuple (e.g.a[i, j]
).bpo-39828: Fix
json.tool
to catchBrokenPipeError
. Patch by Dong-hee Na.bpo-13487: Avoid a possible "RuntimeError: dictionary changed size during iteration" from
inspect.getmodule()
when it tried to loop throughsys.modules
.bpo-39674: Revert "bpo-37330: open() no longer accept 'U' in file mode". The "U" mode of open() is kept in Python 3.9 to ease transition from Python 2.7, but will be removed in Python 3.10.
bpo-28577: The hosts method on 32-bit prefix length IPv4Networks and 128-bit prefix IPv6Networks now returns a list containing the single Address instead of an empty list.
bpo-39826: Add getConnection method to logging HTTPHandler to enable custom connections.
bpo-39763: Reimplement
distutils.spawn.spawn()
function with thesubprocess
module.bpo-39794: Add --without-decimal-contextvar build option. This enables a thread-local rather than a coroutine local context.
bpo-36144:
collections.defaultdict
now implements|
(PEP 584).bpo-39517: Fix runpy.run_path() when using pathlike objects
bpo-39775: Change
inspect.Signature.parameters
back tocollections.OrderedDict
. This was changed todict
in Python 3.9.0a4.bpo-39678: Refactor queue_manager in
concurrent.futures.ProcessPoolExecutor
to make it easier to maintain.bpo-39764: Fix AttributeError when calling get_stack on a PyAsyncGenObject Task
bpo-39769: The
compileall.compile_dir()
function's ddir parameter and the compileall command line flag-d
no longer write the wrong pathname to the generated pyc file for submodules beneath the root of the directory tree being compiled. This fixes a regression introduced with Python 3.5.bpo-36144:
types.MappingProxyType
objects now support the merge (|
) operator from PEP 584.bpo-38691: The
importlib
module now ignores thePYTHONCASEOK
environment variable when the-E
or-I
command line options are being used.bpo-39719: Remove
tempfile.SpooledTemporaryFile.softspace()
as files no longer have thesoftspace
attribute in Python 3. Patch by Shantanu.bpo-39667: Improve pathlib.Path compatibility on zipfile.Path and correct performance degradation as found in zipp 3.0.
bpo-39638: Keep ASDL signatures in the docstrings for
AST
nodes. Patch by Batuhan Taskayabpo-39639: Deprecated
ast.Suite
node class because it's no longer used. Patch by Batuhan Taskaya.bpo-39609: Add thread_name_prefix to default asyncio executor
bpo-39548: Fix handling of header in
urllib.request.AbstractDigestAuthHandler
when the optionalqop
parameter is not present.bpo-39509: HTTP status codes
103 EARLY_HINTS
and425 TOO_EARLY
are added tohttp.HTTPStatus
. Patch by Dong-hee Na.bpo-39507: Adding HTTP status 418 "I'm a Teapot" to HTTPStatus in http library. Patch by Ross Rhodes.
bpo-39495: Remove default value from attrs parameter of
xml.etree.ElementTree.TreeBuilder.start()
for consistency between Python and C implementations.bpo-38971: Open issue in the BPO indicated a desire to make the implementation of codecs.open() at parity with io.open(), which implements a try/except to assure file stream gets closed before an exception is raised.
bpo-38641: Added starred expressions support to
return
andyield
statements forlib2to3
. Patch by Vlad Emelianov.bpo-37534: When using minidom module to generate XML documents the ability to add Standalone Document Declaration is added. All the changes are made to generate a document in compliance with Extensible Markup Language (XML) 1.0 (Fifth Edition) W3C Recommendation (available here: https://www.w3.org/TR/xml/#sec-prolog-dtd).
bpo-34788: Add support for scoped IPv6 addresses to
ipaddress
. Patch by Oleksandr Pavliuk.bpo-34822: Simplified AST for subscription. Simple indices are now represented by their value, extended slices are represented as tuples.
ast
classesIndex
andExtSlice
are considered deprecated and will be removed in future Python versions. In the meantime,Index(value)
now returns avalue
itself,ExtSlice(slices)
returnsTuple(slices, Load())
.
Documentation¶
bpo-13790: Change 'string' to 'specification' in format doc.
bpo-17422: The language reference no longer restricts default class namespaces to dicts only.
bpo-39530: Fix misleading documentation about mixed-type numeric comparisons.
bpo-39718: Update
token
documentation to reflect additions in Python 3.8bpo-39677: Changed operand name of MAKE_FUNCTION from argc to flags for module
dis
Tests¶
bpo-40019: test_gdb now skips tests if it detects that gdb failed to read debug information because the Python binary is optimized.
bpo-27807:
test_site.test_startup_imports()
is now skipped if a path ofsys.path
contains a.pth
file.bpo-26067: Do not fail test_shutil test_chown test when uid or gid of user cannot be resolved to a name.
bpo-39855: test_subprocess.test_user() now skips the test on an user name if the user name doesn't exist. For example, skip the test if the user "nobody" doesn't exist on Linux.
Build¶
bpo-39761: Fix build with DTrace but without additional DFLAGS.
bpo-39763: setup.py now uses a basic implementation of the
subprocess
module if thesubprocess
module is not available: before required C extension modules are built.bpo-1294959: Add
--with-platlibdir
option to the configure script: name of the platform-specific library directory, stored in the newsys.platlibdir
attribute. It is used to build the path of platform-specific extension modules and the path of the standard library. It is equal to"lib"
on most platforms. On Fedora and SuSE, it is equal to"lib64"
on 64-bit platforms. Patch by Jan Matějek, Matěj Cepl, Charalampos Stratakis and Victor Stinner.
Windows¶
bpo-39930: Ensures the required
vcruntime140.dll
is included in install packages.bpo-39847: Avoid hang when computer is hibernated whilst waiting for a mutex (for lock-related objects from
threading
) around 49-day uptime.bpo-38597:
distutils
will no longer statically linkvcruntime140.dll
when a redistributable version is unavailable. All future releases of CPython will include a copy of this DLL to ensure distributed extensions can continue to load.bpo-38380: Update Windows builds to use SQLite 3.31.1
bpo-39789: Update Windows release build machines to Visual Studio 2019 (MSVC 14.2).
bpo-34803: Package for nuget.org now includes repository reference and bundled icon image.
macOS¶
bpo-38380: Update macOS builds to use SQLite 3.31.1
IDLE¶
bpo-27115: For 'Go to Line', use a Query box subclass with IDLE standard behavior and improved error checking.
bpo-39885: Since clicking to get an IDLE context menu moves the cursor, any text selection should be and now is cleared.
bpo-39852: Edit "Go to line" now clears any selection, preventing accidental deletion. It also updates Ln and Col on the status bar.
bpo-39781: Selecting code context lines no longer causes a jump.
Tools/Demos¶
bpo-36184: Port python-gdb.py to FreeBSD. python-gdb.py now checks for "take_gil" function name to check if a frame tries to acquire the GIL, instead of checking for "pthread_cond_timedwait" which is specific to Linux and can be a different condition than the GIL.
bpo-38080: Added support to fix
getproxies
in thelib2to3.fixes.fix_urllib
module. Patch by José Roberto Meza Cabrera.
C API¶
bpo-40024: Add
PyModule_AddType()
helper function: add a type to a module. Patch by Dong-hee Na.bpo-39946: Remove
_PyRuntime.getframe
hook and remove_PyThreadState_GetFrame
macro which was an alias to_PyRuntime.getframe
. They were only exposed by the internal C API. Remove alsoPyThreadFrameGetter
type.bpo-39947: Add
PyThreadState_GetFrame()
function: get the current frame of a Python thread state.bpo-37207: Add _PyArg_NoKwnames helper function. Patch by Dong-hee Na.
bpo-39947: Add
PyThreadState_GetInterpreter()
: get the interpreter of a Python thread state.bpo-39947: Add
PyInterpreterState_Get()
function to the limited C API.bpo-35370: If
PySys_Audit()
fails inPyEval_SetProfile()
orPyEval_SetTrace()
, log the error as an unraisable exception.bpo-39947: Move the static inline function flavor of Py_EnterRecursiveCall() and Py_LeaveRecursiveCall() to the internal C API: they access PyThreadState attributes. The limited C API provides regular functions which hide implementation details.
bpo-39947: Py_TRASHCAN_BEGIN_CONDITION and Py_TRASHCAN_END macro no longer access PyThreadState attributes, but call new private _PyTrash_begin() and _PyTrash_end() functions which hide implementation details.
bpo-39884:
PyDescr_NewMethod()
andPyCFunction_NewEx()
now include the method name in the SystemError "bad call flags" error message to ease debug.bpo-39877: Deprecated
PyEval_InitThreads()
andPyEval_ThreadsInitialized()
. CallingPyEval_InitThreads()
now does nothing.bpo-38249:
Py_UNREACHABLE
is now implemented with__builtin_unreachable()
and analogs in release mode.bpo-38643:
PyNumber_ToBase()
now raises aSystemError
instead of crashing when called with invalid base.bpo-39882: The
Py_FatalError()
function is replaced with a macro which logs automatically the name of the current function, unless thePy_LIMITED_API
macro is defined.bpo-39824: Extension modules:
m_traverse
,m_clear
andm_free
functions ofPyModuleDef
are no longer called if the module state was requested but is not allocated yet. This is the case immediately after the module is created and before the module is executed (Py_mod_exec
function). More precisely, these functions are not called ifm_size
is greater than 0 and the module state (as returned byPyModule_GetState()
) isNULL
.Extension modules without module state (
m_size <= 0
) are not affected.bpo-38913: Fixed segfault in
Py_BuildValue()
called with a format containing "#" and undefined PY_SSIZE_T_CLEAN whwn an exception is set.bpo-38500: Add a private API to get and set the frame evaluation function: add
_PyInterpreterState_GetEvalFrameFunc()
and_PyInterpreterState_SetEvalFrameFunc()
C functions. The_PyFrameEvalFunction
function type now takes a tstate parameter.
Python 3.9.0 alpha 4¶
Release date: 2020-02-25
Security¶
Core and Builtins¶
bpo-39382: Fix a use-after-free in the single inheritance path of
issubclass()
, when the__bases__
of an object has a single reference, and so does its first item. Patch by Yonatan Goldschmidt.bpo-39573: Update clinic tool to use
Py_IS_TYPE()
. Patch by Dong-hee Na.bpo-39619: Enable use of
os.chroot()
on HP-UX systems.bpo-39573: Add
Py_IS_TYPE()
static inline function to check whether the object o type is type.bpo-39606: Fix regression caused by fix for bpo-39386, that prevented calling
aclose
on an async generator that had already been closed or exhausted.bpo-39579: Change the ending column offset of
Attribute
nodes constructed inast_for_dotted_name
to point at the end of the current node and not at the end of the lastNAME
node.bpo-1635741: Port _crypt extension module to multiphase initialization (PEP 489).
bpo-1635741: Port _contextvars extension module to multiphase initialization (PEP 489).
bpo-39510: Fix segfault in
readinto()
method on closed BufferedReader.bpo-39502: Fix
time.localtime()
on 64-bit AIX to support years before 1902 and after 2038. Patch by M Felt.bpo-39492: Fix a reference cycle in the C Pickler that was preventing the garbage collection of deleted, pickled objects.
bpo-39453: Fixed a possible crash in
list.__contains__()
when a list is changed during comparing items. Patch by Dong-hee Na.bpo-39434: floor division of float operation now has a better performance. Also the message of
ZeroDivisionError
for this operation is updated. Patch by Dong-hee Na.bpo-1635741: Port _codecs extension module to multiphase initialization (PEP 489).
bpo-1635741: Port _bz2 extension module to multiphase initialization (PEP 489).
bpo-1635741: Port _abc extension module to multiphase initialization (PEP 489).
bpo-39320: Replace two complex bytecodes for building dicts with two simpler ones. The new bytecodes
DICT_MERGE
andDICT_UPDATE
have been added The old bytecodesBUILD_MAP_UNPACK
andBUILD_MAP_UNPACK_WITH_CALL
have been removed.bpo-39219: Syntax errors raised in the tokenizer now always set correct "text" and "offset" attributes.
bpo-36051: Drop the GIL during large
bytes.join
operations. Patch by Bruce Merry.bpo-38960: Fix DTrace build issues on FreeBSD. Patch by David Carlier.
bpo-37207: Speed up calls to
range()
by about 30%, by using the PEP 590vectorcall
calling convention. Patch by Mark Shannon.bpo-36144:
dict
(andcollections.UserDict
) objects now support PEP 584's merge (|
) and update (|=
) operators. Patch by Brandt Bucher.bpo-32856: Optimized the idiom for assignment a temporary variable in comprehensions. Now
for y in [expr]
in comprehensions is as fast as a simple assignmenty = expr
.
Library¶
bpo-30566: Fix
IndexError
when trying to decode an invalid string with punycode codec.bpo-39649: Remove obsolete check for
__args__
in bdb.Bdb.format_stack_entry.bpo-39648: Expanded
math.gcd()
andmath.lcm()
to handle multiple arguments.bpo-39681: Fix a regression where the C pickle module wouldn't allow unpickling from a file-like object that doesn't expose a readinto() method.
bpo-35950: Raise
io.UnsupportedOperation
inio.BufferedReader.truncate()
when it is called on a read-onlyio.BufferedReader
instance.bpo-39479: Add
math.lcm()
function: least common multiple.bpo-39674: Revert "Do not expose abstract collection classes in the collections module" change (bpo-25988). Aliases to ABC like collections.Mapping are kept in Python 3.9 to ease transition from Python 2.7, but will be removed in Python 3.10.
bpo-39104: Fix hanging ProcessPoolExcutor on
shutdown(wait=False)
when a task has failed pickling.bpo-39627: Fixed TypedDict totality check for inherited keys.
bpo-39474: Fixed starting position of AST for expressions like
(a)(b)
,(a)[b]
and(a).b
.bpo-21016: The
pydoc
andtrace
modules now use thesysconfig
module to get the path to the Python standard library, to support uncommon installation path like/usr/lib64/python3.9/
on Fedora. Patch by Jan Matějek.bpo-39590: Collections.deque now holds strong references during deque.__contains__ and deque.count, fixing crashes.
bpo-39586: The distutils
bdist_msi
command is deprecated in Python 3.9, usebdist_wheel
(wheel packages) instead.bpo-39595: Improved performance of zipfile.Path for files with a large number of entries. Also improved performance and fixed minor issue as published with importlib_metadata 1.5.
bpo-39350: Fix regression in
fractions.Fraction
if the numerator and/or the denominator is anint
subclass. Themath.gcd()
function is now used to normalize the numerator and denominator.math.gcd()
always return aint
type. Previously, the GCD type depended on numerator and denominator.bpo-39567: Added audit for
os.walk()
,os.fwalk()
,pathlib.Path.glob()
andpathlib.Path.rglob()
.bpo-39559: Remove unused, undocumented argument
getters
fromuuid.getnode()
bpo-38149:
sys.audit()
is now called only once per call ofglob.glob()
andglob.iglob()
.bpo-39546: Fix a regression in
ArgumentParser
whereallow_abbrev=False
was ignored for long options that used a prefix character other than "-".bpo-39450: Striped whitespace from docstring before returning it from
unittest.case.shortDescription()
.bpo-12915: A new function
resolve_name
has been added to thepkgutil
module. This resolves a string of the form'a.b.c.d'
or'a.b:c.d'
to an object. In the example,a.b
is a package/module andc.d
is an object within that package/module reached via recursive attribute access.bpo-39353: The
binascii.crc_hqx()
function is no longer deprecated.bpo-39493: Mark
typing.IO.closed
as a propertybpo-39491: Add
typing.Annotated
andinclude_extras
parameter totyping.get_type_hints()
as part of PEP 593. Patch by Till Varoquaux, documentation by Till Varoquaux and Konstantin Kashin.bpo-39485: Fix a bug in
unittest.mock.create_autospec()
that would complain about the wrong number of arguments for custom descriptors defined in an extension module returning functions.bpo-38932: Mock fully resets child objects on reset_mock(). Patch by Vegard Stikbakke
bpo-39082: Allow AsyncMock to correctly patch static/class methods
bpo-39432: Implement PEP-489 algorithm for non-ascii "PyInit_..." symbol names in distutils to make it export the correct init symbol also on Windows.
bpo-18819: Omit
devmajor
anddevminor
fields for non-device files intarfile
archives, enabling bit-for-bit compatibility with GNUtar(1)
.bpo-39349: Added a new cancel_futures parameter to
concurrent.futures.Executor.shutdown()
that cancels all pending futures which have not started running, instead of waiting for them to complete before shutting down the executor.bpo-39274:
bool(fraction.Fraction)
now returns a boolean even if (numerator != 0) does not return a boolean (ex: numpy number).bpo-34793: Remove support for
with (await asyncio.lock):
andwith (yield from asyncio.lock):
. The same is correct forasyncio.Condition
andasyncio.Semaphore
.bpo-25597: Ensure, if
wraps
is supplied tounittest.mock.MagicMock
, it is used to calculate return values for the magic methods instead of using the default return values. Patch by Karthikeyan Singaravelan.bpo-36350:
inspect.Signature.parameters
andinspect.BoundArguments.arguments
are now dicts instead of OrderedDicts. Patch contributed by Rémi Lapeyre.bpo-35727: Fix sys.exit() and sys.exit(None) exit code propagation when used in multiprocessing.Process.
bpo-32173: * Add
lazycache
function to__all__
. * Usedict.clear
to clear the cache. * Refactoringgetline
function andcheckcache
function.
Documentation¶
bpo-17422: The language reference now specifies restrictions on class namespaces. Adapted from a patch by Ethan Furman.
bpo-39572: Updated documentation of
total
flag ofTypedDict
.bpo-39654: In pyclbr doc, update 'class' to 'module' where appropriate and add readmodule comment. Patch by Hakan Çelik.
bpo-39153: Clarify refcounting semantics for the following functions: - PyObject_SetItem - PyMapping_SetItemString - PyDict_SetItem - PyDict_SetItemString
bpo-39392: Explain that when filling with turtle, overlap regions may be left unfilled.
bpo-39369: Update mmap readline method description. The fact that the readline method does update the file position should not be ignored since this might give the impression for the programmer that it doesn't update it.
bpo-9056: Include subsection in TOC for PDF version of docs.
Tests¶
bpo-38325: Skip tests on non-BMP characters of test_winconsoleio.
bpo-39502: Skip test_zipfile.test_add_file_after_2107() if
time.localtime()
fails withOverflowError
. It is the case on AIX 6.1 for example.
Build¶
bpo-39489: Remove
COUNT_ALLOCS
special build.
Windows¶
bpo-39553: Delete unused code related to SxS manifests.
bpo-39439: Honor the Python path when a virtualenv is active on Windows.
bpo-39393: Improve the error message when attempting to load a DLL with unresolved dependencies.
bpo-38883:
home()
andexpanduser()
on Windows now preferUSERPROFILE
and no longer useHOME
, which is not normally set for regular user accounts. This makes them again behave likeos.path.expanduser()
, which was changed to ignoreHOME
in 3.8, see bpo-36264.bpo-39185: The build.bat script has additional options for very-quiet output (-q) and very-verbose output (-vv)
IDLE¶
bpo-39663: Add tests for pyparse find_good_parse_start().
bpo-39600: In the font configuration window, remove duplicated font names.
bpo-30780: Add remaining configdialog tests for buttons and highlights and keys tabs.
bpo-39388: IDLE Settings Cancel button now cancels pending changes
bpo-38792: Close an IDLE shell calltip if a
KeyboardInterrupt
or shell restart occurs. Patch by Zackery Spytz.
C API¶
bpo-35081: Move the
bytes_methods.h
header file to the internal C API aspycore_bytes_methods.h
: it only contains private symbols (prefixed by_Py
), except of thePyDoc_STRVAR_shared()
macro.bpo-35081: Move the
dtoa.h
header file to the internal C API aspycore_dtoa.h
: it only contains private functions (prefixed by_Py
). Themath
andcmath
modules must now be compiled with thePy_BUILD_CORE
macro defined.bpo-39573: Add
Py_SET_SIZE()
function to set the size of an object.bpo-39500:
PyUnicode_IsIdentifier()
does not callPy_FatalError()
anymore if the string is not ready.bpo-39573: Add
Py_SET_TYPE()
function to set the type of an object.bpo-39573: Add a
Py_SET_REFCNT()
function to set the reference counter of an object.bpo-39542: Convert
PyType_HasFeature()
,PyType_Check()
andPyType_CheckExact()
macros to static inline functions.bpo-39542: In the limited C API,
PyObject_INIT()
andPyObject_INIT_VAR()
are now defined as aliases toPyObject_Init()
andPyObject_InitVar()
to make their implementation opaque. It avoids to leak implementation details in the limited C API. Exclude the following functions from the limited C API:_Py_NewReference()
,_Py_ForgetReference()
,_PyTraceMalloc_NewReference()
and_Py_GetRefTotal()
.bpo-39542: Exclude trashcan mechanism from the limited C API: it requires access to PyTypeObject and PyThreadState structure fields, whereas these structures are opaque in the limited C API.
bpo-39511: The
PyThreadState_Clear()
function now calls thePyThreadState.on_delete
callback. Previously, that happened inPyThreadState_Delete()
.bpo-38076: Fix to clear the interpreter state only after clearing module globals to guarantee module state access from C Extensions during runtime destruction
bpo-39245: The Vectorcall API (PEP 590) was made public, adding the functions
PyObject_Vectorcall
,PyObject_VectorcallMethod
,PyVectorcall_Function
,PyObject_CallOneArg
,PyObject_CallMethodNoArgs
,PyObject_CallMethodOneArg
,PyObject_FastCallDict
, and the flagPy_TPFLAGS_HAVE_VECTORCALL
.
Python 3.9.0 alpha 3¶
Release date: 2020-01-24
Core and Builtins¶
bpo-39427: Document all possibilities for the
-X
options in the command line help section. Patch by Pablo Galindo.bpo-39421: Fix possible crashes when operating with the functions in the
heapq
module and custom comparison operators.bpo-39386: Prevent double awaiting of async iterator.
bpo-17005: Add
functools.TopologicalSorter
to thefunctools
module to offers functionality to perform topological sorting of graphs. Patch by Pablo Galindo, Tim Peters and Larry Hastings.bpo-39320: Replace four complex bytecodes for building sequences with three simpler ones.
The following four bytecodes have been removed:
BUILD_LIST_UNPACK
BUILD_TUPLE_UNPACK
BUILD_SET_UNPACK
BUILD_TUPLE_UNPACK_WITH_CALL
The following three bytecodes have been added:
LIST_TO_TUPLE
LIST_EXTEND
SET_UPDATE
bpo-39336: Import loaders which publish immutable module objects can now publish immutable packages in addition to individual modules.
bpo-39322: Added a new function
gc.is_finalized()
to check if an object has been finalized by the garbage collector. Patch by Pablo Galindo.bpo-39048: Improve the displayed error message when incorrect types are passed to
async with
statements by looking up the__aenter__()
special method before the__aexit__()
special method when entering an asynchronous context manager. Patch by Géry Ogam.bpo-39235: Fix AST end location for lone generator expression in function call, e.g. f(i for i in a).
bpo-39209: Correctly handle multi-line tokens in interactive mode. Patch by Pablo Galindo.
bpo-1635741: Port _json extension module to multiphase initialization (PEP 489).
bpo-39216: Fix constant folding optimization for positional only arguments - by Anthony Sottile.
bpo-39215: Fix
SystemError
when nested function has annotation on positional-only argument - by Anthony Sottile.bpo-39200: Correct the error message when calling the
min()
ormax()
with no arguments. Patch by Dong-hee Na.bpo-39200: Correct the error message when trying to construct
range
objects with no arguments. Patch by Pablo Galindo.bpo-39166: Fix incorrect line execution reporting in trace functions when tracing the last iteration of asynchronous for loops. Patch by Pablo Galindo.
bpo-39114: Fix incorrect line execution reporting in trace functions when tracing exception handlers with name binding. Patch by Pablo Galindo.
bpo-39156: Split the COMPARE_OP bytecode instruction into four distinct instructions.
COMPARE_OP for rich comparisons
IS_OP for 'is' and 'is not' tests
CONTAINS_OP for 'in' and 'is not' tests
JUMP_IF_NOT_EXC_MATCH for checking exceptions in 'try-except' statements.
This improves the clarity of the interpreter and should provide a modest speedup.
bpo-38588: Fix possible crashes in dict and list when calling
PyObject_RichCompareBool()
.bpo-13601: By default,
sys.stderr
is line-buffered now, even ifstderr
is redirected to a file. You can still makesys.stderr
unbuffered by passing the-u
command-line option or setting thePYTHONUNBUFFERED
environment variable.(Contributed by Jendrik Seipp in bpo-13601.)
bpo-38610: Fix possible crashes in several list methods by holding strong references to list elements when calling
PyObject_RichCompareBool()
.bpo-32021: Include brotli .br encoding in mimetypes encodings_map
Library¶
bpo-39413: The
os.unsetenv()
function is now also available on Windows.bpo-39390: Fixed a regression with the
ignore
callback ofshutil.copytree()
. The argument types are now str and List[str] again.bpo-39395: The
os.putenv()
andos.unsetenv()
functions are now always available.bpo-39406: If
setenv()
C function is available,os.putenv()
is now implemented withsetenv()
instead ofputenv()
, so Python doesn't have to handle the environment variable memory.bpo-39396: Fix
math.nextafter(-0.0, +0.0)
on AIX 7.1.bpo-29435: Allow
tarfile.is_tarfile()
to be used with file and file-like objects, likezipfile.is_zipfile()
. Patch by William Woodruff.bpo-39377: Removed
encoding
option fromjson.loads()
. It has been deprecated since Python 3.1.bpo-39389: Write accurate compression level metadata in
gzip
archives, rather than always signaling maximum compression.bpo-39366: The previously deprecated
xpath()
andxgtitle()
methods ofnntplib.NNTP
have been removed.bpo-39357: Remove the buffering parameter of
bz2.BZ2File
. Since Python 3.0, it was ignored and using it was emittingDeprecationWarning
. Pass an open file object, to control how the file is opened. The compresslevel parameter becomes keyword-only.bpo-39353: Deprecate binhex4 and hexbin4 standards. Deprecate the
binhex
module and the followingbinascii
functions:b2a_hqx()
,a2b_hqx()
,rlecode_hqx()
,rledecode_hqx()
,crc_hqx()
.bpo-39351: Remove
base64.encodestring()
andbase64.decodestring()
, aliases deprecated since Python 3.1: usebase64.encodebytes()
andbase64.decodebytes()
instead.bpo-39350: Remove
fractions.gcd()
function, deprecated since Python 3.5 (bpo-22486): usemath.gcd()
instead.bpo-39329:
LMTP
constructor now has an optional timeout parameter. Patch by Dong-hee Na.bpo-39313: Add a new
exec_function
option (--exec-function in the CLI) toRefactoringTool
for makingexec
a function. Patch by Batuhan Taskaya.bpo-39259:
FTP_TLS
andFTP_TLS
now raise aValueError
if the given timeout for their constructor is zero to prevent the creation of a non-blocking socket. Patch by Dong-hee Na.bpo-39259:
SMTP
andSMTP_SSL
now raise aValueError
if the given timeout for their constructor is zero to prevent the creation of a non-blocking socket. Patch by Dong-hee Na.bpo-39310: Add
math.ulp()
: return the value of the least significant bit of a float.bpo-39297: Improved performance of importlib.metadata distribution discovery and resilients to inaccessible sys.path entries (importlib_metadata v1.4.0).
bpo-39259:
NNTP
andNNTP_SSL
now raise aValueError
if the given timeout for their constructor is zero to prevent the creation of a non-blocking socket. Patch by Dong-hee Na.bpo-38901: When you specify prompt='.' or equivalently python -m venv --prompt . ... the basename of the current directory is used to set the created venv's prompt when it's activated.
bpo-39288: Add
math.nextafter()
: return the next floating-point value after x towards y.bpo-39259:
POP3
andPOP3_SSL
now raise aValueError
if the given timeout for their constructor is zero to prevent the creation of a non-blocking socket. Patch by Dong-hee Na.bpo-39242: Updated the Gmane domain from news.gmane.org to news.gmane.io which is used for examples of
NNTP
news reader server and nntplib tests.bpo-35292: Proxy the
SimpleHTTPRequestHandler.guess_type
tomimetypes.guess_type
so themimetypes.init
is called lazily to avoid unnecessary costs whenhttp.server
module is imported.bpo-39239: The
select.epoll.unregister()
method no longer ignores theEBADF
error.bpo-38907: In http.server script, restore binding to IPv4 on Windows.
bpo-39152: Fix ttk.Scale.configure([name]) to return configuration tuple for name or all options. Giovanni Lombardo contributed part of the patch.
bpo-39198: If an exception were to be thrown in
Logger.isEnabledFor
(say, by asyncio timeouts or stopit) , thelogging
global lock may not be released appropriately, resulting in deadlock. This change wraps that block of code withtry...finally
to ensure the lock is released.bpo-39191: Perform a check for running loop before starting a new task in
loop.run_until_complete()
to fail fast; it prevents the side effect of new task spawning before exception raising.bpo-38871: Correctly parenthesize filter-based statements that contain lambda expressions in mod:
lib2to3
. Patch by Dong-hee Na.bpo-39142: A change was made to logging.config.dictConfig to avoid converting instances of named tuples to ConvertingTuple. It's assumed that named tuples are too specialised to be treated like ordinary tuples; if a user of named tuples requires ConvertingTuple functionality, they will have to implement that themselves in their named tuple class.
bpo-39158: ast.literal_eval() now supports empty sets.
bpo-39129: Fix import path for
asyncio.TimeoutError
bpo-39057:
urllib.request.proxy_bypass_environment()
now ignores leading dots and no longer ignores a trailing newline.bpo-39056: Fixed handling invalid warning category in the -W option. No longer import the re module if it is not needed.
bpo-39055:
base64.b64decode()
withvalidate=True
raises now a binascii.Error if the input ends with a single\n
.bpo-21600: Fix
mock.patch.stopall()
to stop active patches that were created withmock.patch.dict()
.bpo-39019: Implement dummy
__class_getitem__
fortempfile.SpooledTemporaryFile
.bpo-39019: Implement dummy
__class_getitem__
forsubprocess.Popen
,subprocess.CompletedProcess
bpo-38914: Adjusted the wording of the warning issued by distutils'
check
command when theauthor
andmaintainer
fields are supplied but no corresponding e-mail field (author_email
ormaintainer_email
) is found. The wording now reflects the fact that these fields are suggested, but not required. Patch by Juergen Gmach.bpo-38878: Fixed __subclasshook__ of
os.PathLike
to return a correct result upon inheritance. Patch by Bar Harel.bpo-38615:
IMAP4
andIMAP4_SSL
now have an optional timeout parameter for their constructors. Also, theopen()
method now has an optional timeout parameter with this change. The overridden methods ofIMAP4_SSL
andIMAP4_stream
were applied to this change. Patch by Dong-hee Na.bpo-35182: Fixed
Popen.communicate()
subsequent call crash when the child process has already closed any piped standard stream, but still continues to be running. Patch by Andriy Maletsky.bpo-38630: On Unix,
subprocess.Popen.send_signal()
now polls the process status. Polling reduces the risk of sending a signal to the wrong process if the process completed, thesubprocess.Popen.returncode
attribute is stillNone
, and the pid has been reassigned (recycled) to a new different process.bpo-38536: Removes trailing space in formatted currency with
international=True
and a locale with symbol following value. E.g.locale.currency(12.34, international=True)
returned'12,34 EUR '
instead of'12,34 EUR'
.bpo-38473: Use signature from inner mock for autospecced methods attached with
unittest.mock.attach_mock()
. Patch by Karthikeyan Singaravelan.bpo-38361: Fixed an issue where
ident
could include a leading path separator whensyslog.openlog()
was called without arguments.bpo-38293: Add
copy.copy()
andcopy.deepcopy()
support toproperty()
objects.bpo-37958: Added the pstats.Stats.get_profile_dict() method to return the profile data as a StatsProfile instance.
bpo-28367: Termios magic constants for the following baud rates: - B500000 - B576000 - B921600 - B1000000 - B1152000 - B1500000 - B2000000 - B2500000 - B3000000 - B3500000 - B4000000 Patch by Andrey Smirnov
Documentation¶
bpo-39381: Mention in docs that
asyncio.get_event_loop()
implicitly creates new event loop only if called from the main thread.bpo-38918: Add an entry for
__module__
in the "function" & "method" sections of the inspect docs types and members tablebpo-3530: In the
ast
module documentation, fix a misleadingNodeTransformer
example and add advice on when to use thefix_missing_locations
function.
Build¶
bpo-39395: On non-Windows platforms, the
setenv()
andunsetenv()
functions are now required to build Python.bpo-39160: Updated the documentation in
/configure --help
to show default values, reference documentation where required and add additional explanation where needed.bpo-39144: The ctags and etags build targets both include Modules/_ctypes and Python standard library source files.
IDLE¶
bpo-39050: Make IDLE Settings dialog Help button work again.
bpo-34118: Tag memoryview, range, and tuple as classes, the same as list, etcetera, in the library manual built-in functions list.
bpo-32989: Add tests for editor newline_and_indent_event method. Remove dead code from pyparse find_good_parse_start method.
C API¶
bpo-39372: Clean header files of interfaces defined but with no implementation. The public API symbols being removed are:
_PyBytes_InsertThousandsGroupingLocale
,_PyBytes_InsertThousandsGrouping
,_Py_InitializeFromArgs
,_Py_InitializeFromWideArgs
,_PyFloat_Repr
,_PyFloat_Digits
,_PyFloat_DigitsInit
,PyFrame_ExtendStack
,_PyAIterWrapper_Type
,PyNullImporter_Type
,PyCmpWrapper_Type
,PySortWrapper_Type
,PyNoArgsFunction
.bpo-39164: Add a private
_PyErr_GetExcInfo()
function to retrieve exception information of the specified Python thread state.
Python 3.9.0 alpha 2¶
Release date: 2019-12-18
Security¶
bpo-38945: Newline characters have been escaped when performing uu encoding to prevent them from overflowing into to content section of the encoded file. This prevents malicious or accidental modification of data during the decoding process.
bpo-37228: Due to significant security concerns, the reuse_address parameter of
asyncio.loop.create_datagram_endpoint()
is no longer supported. This is because of the behavior ofSO_REUSEADDR
in UDP. For more details, see the documentation forloop.create_datagram_endpoint()
. (Contributed by Kyle Stanley, Antoine Pitrou, and Yury Selivanov in bpo-37228.)bpo-38804: Fixes a ReDoS vulnerability in
http.cookiejar
. Patch by Ben Caller.
Core and Builtins¶
bpo-39028: Slightly improve the speed of keyword argument parsing with many kwargs by strengthening the assumption that kwargs are interned strings.
bpo-39080: Fix the value of end_col_offset for Starred Expression AST nodes when they are among the elements in the args attribute of Call AST nodes.
bpo-39031: When parsing an "elif" node, lineno and col_offset of the node now point to the "elif" keyword and not to its condition, making it consistent with the "if" node. Patch by Lysandros Nikolaou.
bpo-20443: In Python 3.9.0a1, sys.argv[0] was made an absolute path if a filename was specified on the command line. Revert this change, since most users expect sys.argv to be unmodified.
bpo-39008:
PySys_Audit()
now requiresPy_ssize_t
to be used for size arguments in the format string, regardless of whetherPY_SSIZE_T_CLEAN
was defined at include time.bpo-38673: In REPL mode, don't switch to PS2 if the line starts with comment or whitespace. Based on work by Batuhan Taşkaya.
bpo-38922: Calling
replace
on a code object now raises thecode.__new__
audit event.bpo-38920: Add audit hooks for when
sys.excepthook()
andsys.unraisablehook()
are invoked.bpo-38892: Improve documentation for audit events table and functions.
bpo-38852: Set the thread stack size to 8 Mb for debug builds on android platforms.
bpo-38858: Each Python subinterpreter now has its own "small integer singletons": numbers in [-5; 257] range. It is no longer possible to change the number of small integers at build time by overriding
NSMALLNEGINTS
andNSMALLPOSINTS
macros: macros should now be modified manually inpycore_pystate.h
header file.bpo-36854: The garbage collector state becomes per interpreter (
PyInterpreterState.gc
), rather than being global (_PyRuntimeState.gc
).bpo-38835: The
PyFPE_START_PROTECT()
andPyFPE_END_PROTECT()
macros are empty: they have been doing nothing for the last year, so stop using them.bpo-38328: Sped up the creation time of constant
list
andset
displays. Patch by Brandt Bucher.bpo-38707:
MainThread.native_id
is now correctly reset in child processes spawned usingmultiprocessing.Process
, instead of retaining the parent's value.bpo-38629: Added
__floor__
and__ceil__
methods to float object. Patch by Batuhan Taşkaya.bpo-27145: int + int and int - int operators can now return small integer singletons. Patch by hongweipeng.
bpo-38021: Provide a platform tag for AIX that is sufficient for PEP425 binary distribution identification. Patch by Michael Felt.
bpo-35409: Ignore GeneratorExit exceptions when throwing an exception into the aclose coroutine of an asynchronous generator.
bpo-33387: Removed WITH_CLEANUP_START, WITH_CLEANUP_FINISH, BEGIN_FINALLY, END_FINALLY, CALL_FINALLY and POP_FINALLY bytecodes. Replaced with RERAISE and WITH_EXCEPT_START bytecodes. The compiler now generates different code for exceptional and non-exceptional branches for 'with' and 'try-except' statements. For 'try-finally' statements the 'finally' block is replicated for each exit from the 'try' body.
Library¶
bpo-39033: Fix
NameError
inzipimport
. Patch by Karthikeyan Singaravelan.bpo-39022: Update importlib.metadata to include improvements from importlib_metadata 1.3 including better serialization of EntryPoints and improved documentation for custom finders.
bpo-39006: Fix asyncio when the ssl module is missing: only check for ssl.SSLSocket instance if the ssl module is available.
bpo-38708: Fix a potential IndexError in email parser when parsing an empty msg-id.
bpo-38698: Add a new
InvalidMessageID
token to email parser to represent invalid Message-ID headers. Also, add defects when there is remaining value after parsing the header.bpo-38994: Implement
__class_getitem__
foros.PathLike
,pathlib.Path
.bpo-38979: Return class from
ContextVar.__class_getitem__
to simplify subclassing.bpo-38978: Implement
__class_getitem__
on asyncio objects (Future, Task, Queue). Patch by Batuhan Taskaya.bpo-38916:
array.array
: Removetostring()
andfromstring()
methods. They were aliases totobytes()
andfrombytes()
, deprecated since Python 3.2.bpo-38986: Make repr of C accelerated TaskWakeupMethWrapper the same as of pure Python version.
bpo-38982: Fix asyncio
PidfdChildWatcher
: handlewaitpid()
error. Ifwaitpid()
is called elsewhere,waitpid()
call fails withChildProcessError
: use return code 255 in this case, and log a warning. It ensures that the pidfd file descriptor is closed if this error occurs.bpo-38529: Drop too noisy asyncio warning about deletion of a stream without explicit
.close()
call.bpo-27413: Added ability to pass through
ensure_ascii
options to json.dumps in thejson.tool
command-line interface.bpo-38634: The
readline
module now detects if Python is linked to libedit at runtime on all platforms. Previously, the check was only done on macOS.bpo-33684: Fix
json.tool
failed to read a JSON file with non-ASCII characters when locale encoding is not UTF-8.bpo-38698: Prevent UnboundLocalError to pop up in parse_message_id.
parse_message_id() was improperly using a token defined inside an exception handler, which was raising
UnboundLocalError
on parsing an invalid value. Patch by Claudiu Popa.bpo-38927: Use
python -m pip
instead ofpip
to upgrade dependencies in venv.bpo-26730: Fix
SpooledTemporaryFile.rollover()
might corrupt the file when it is in text mode. Patch by Serhiy Storchaka.bpo-38881: random.choices() now raises a ValueError when all the weights are zero.
bpo-38876: Raise pickle.UnpicklingError when loading an item from memo for invalid input.
The previous code was raising a
KeyError
for both the Python and C implementation. This was caused by the specified index of an invalid input which did not exist in the memo structure, where the pickle stores what objects it has seen. The malformed input would have caused either aBINGET
orLONG_BINGET
load from the memo, leading to aKeyError
as the determined index was bogus. Patch by Claudiu Popabpo-38688: Calling func:
shutil.copytree
to copy a directory tree from one directory to another subdirectory resulted in an endless loop and a RecursionError. A fix was added to consume an iterator and create the list of the entries to be copied, avoiding the recursion for newly created directories. Patch by Bruno P. Kinoshita.bpo-38863: Improve
is_cgi()
function inhttp.server
, which enables processing the case that cgi directory is a child of another directory other than root.bpo-37838:
typing.get_type_hints()
properly handles functions decorated withfunctools.wraps()
.bpo-38870: Expose
ast.unparse()
as a function of theast
module that can be used to unparse anast.AST
object and produce a string with code that would produce an equivalentast.AST
object when parsed. Patch by Pablo Galindo and Batuhan Taskaya.bpo-38859: AsyncMock now returns StopAsyncIteration on the exhaustion of a side_effects iterable. Since PEP-479 its Impossible to raise a StopIteration exception from a coroutine.
bpo-38857: AsyncMock fix for return values that are awaitable types. This also covers side_effect iterable values that happened to be awaitable, and wraps callables that return an awaitable type. Before these awaitables were being awaited instead of being returned as is.
bpo-38834:
typing.TypedDict
subclasses now track which keys are optional using the__required_keys__
and__optional_keys__
attributes, to enable runtime validation by downstream projects. Patch by Zac Hatfield-Dodds.bpo-38821: Fix unhandled exceptions in
argparse
when internationalizing error messages for arguments withnargs
set to special (non-integer) values. Patch by Federico Bond.bpo-38820: Make Python compatible with OpenSSL 3.0.0.
ssl.SSLSocket.getpeercert()
no longer returns IPv6 addresses with a trailing new line.bpo-38811: Fix an unhandled exception in
pathlib
whenos.link()
is missing. Patch by Toke Høiland-Jørgensen.bpo-38686: Added support for multiple
qop
values inurllib.request.AbstractDigestAuthHandler
.bpo-38712: Add the Linux-specific
signal.pidfd_send_signal()
function, which allows sending a signal to a process identified by a file descriptor rather than a pid.bpo-38348: Add
-i
and--indent
(indentation level), and--no-type-comments
(type comments) command line options to ast parsing tool.bpo-37523: Change
zipfile.ZipExtFile
to raiseValueError
when trying to access the underlying file object after it has been closed. This new behavior is consistent with how accessing closed files is handled in other parts of Python.bpo-38045: Improve the performance of
enum._decompose()
inenum
. Patch by hongweipeng.bpo-36820: Break cycle generated when saving an exception in socket.py, codeop.py and dyld.py as they keep alive not only the exception but user objects through the
__traceback__
attribute. Patch by Mario Corchero.bpo-36406: Handle namespace packages in
doctest
. Patch by Karthikeyan Singaravelan.bpo-34776: Fix dataclasses to support forward references in type annotations
bpo-20928: ElementTree supports recursive XInclude processing. Patch by Stefan Behnel.
bpo-29636: Add whitespace options for formatting JSON with the
json.tool
CLI. The following mutually exclusive options are now supported:--indent
for setting the indent level in spaces;--tab
for indenting with tabs;--no-indent
for suppressing newlines; and--compact
for suppressing all whitespace. The default behavior remains the same as--indent=4
.
Documentation¶
bpo-38928: Correct when venv's
upgrade_dependencies()
and--upgrade-deps
are added.bpo-38899: Update documentation to state that to activate virtual environments under fish one should use
source
, notas documented at https://fishshell.com/docs/current/commands.html#source.
bpo-22377: Improves documentation of the values that
datetime.datetime.strptime()
accepts for%Z
. Patch by Karl Dubost.
Tests¶
bpo-38546: Fix test_ressources_gced_in_workers() of test_concurrent_futures: explicitly stop the manager to prevent leaking a child process running in the background after the test completes.
bpo-38546: Multiprocessing and concurrent.futures tests now stop the resource tracker process when tests complete.
bpo-38614: Replace hardcoded timeout constants in tests with new
test.support
constants:LOOPBACK_TIMEOUT
,INTERNET_TIMEOUT
,SHORT_TIMEOUT
andLONG_TIMEOUT
. It becomes easier to adjust these four timeout constants for all tests at once, rather than having to adjust every single test file.bpo-38547: Fix test_pty: if the process is the session leader, closing the master file descriptor raises a SIGHUP signal: simply ignore SIGHUP when running the tests.
bpo-38992: Fix a test for
math.fsum()
that was failing due to constant folding.bpo-38991:
test.support
:run_python_until_end()
,assert_python_ok()
andassert_python_failure()
functions no longer strip whitespaces from stderr. Removetest.support.strip_python_stderr()
function.bpo-38965: Fix test_faulthandler on GCC 10. Use the "volatile" keyword in
faulthandler._stack_overflow()
to prevent tail call optimization on any compiler, rather than relying on compiler specific pragma.bpo-38875: test_capi: trashcan tests now require the test "cpu" resource.
bpo-38841: Skip asyncio test_create_datagram_endpoint_existing_sock_unix on platforms lacking a functional bind() for named unix domain sockets.
bpo-38692: Skip the test_posix.test_pidfd_open() test if
os.pidfd_open()
fails with aPermissionError
. This situation can happen in a Linux sandbox using a syscall whitelist which doesn't allow thepidfd_open()
syscall yet.bpo-38839: Fix some unused functions in tests. Patch by Adam Johnson.
bpo-38669: Raise
TypeError
when passing target as a string withunittest.mock.patch.object()
.bpo-37957: test.regrtest now can receive a list of test patterns to ignore (using the -i/--ignore argument) or a file with a list of patterns to ignore (using the --ignore-file argument). Patch by Pablo Galindo.
Build¶
bpo-37404:
asyncio
now raisesTyperError
when calling incompatible methods with anssl.SSLSocket
socket. Patch by Ido Michael.bpo-36500: Added an optional "regen" project to the Visual Studio solution that will regenerate all grammar, tokens, and opcodes.
Windows¶
macOS¶
bpo-37931: Fixed a crash on OSX dynamic builds that occurred when re-initializing the posix module after a Py_Finalize if the environment had changed since the previous
import posix
. Patch by Benoît Hudson.
IDLE¶
bpo-38944: Escape key now closes IDLE completion windows. Patch by Johnny Najera.
bpo-38943: Fix IDLE autocomplete windows not always appearing on some systems. Patch by Johnny Najera.
bpo-38862: 'Strip Trailing Whitespace' on the Format menu removes extra newlines at the end of non-shell files.
bpo-38636: Fix IDLE Format menu tab toggle and file indent width. These functions (default shortcuts Alt-T and Alt-U) were mistakenly disabled in 3.7.5 and 3.8.0.
C API¶
bpo-38896: Remove
PyUnicode_ClearFreeList()
function: the Unicode free list has been removed in Python 3.3.bpo-37340: Remove
PyMethod_ClearFreeList()
andPyCFunction_ClearFreeList()
functions: the free lists of bound method objects have been removed.bpo-38835: Exclude
PyFPE_START_PROTECT()
andPyFPE_END_PROTECT()
macros ofpyfpe.h
fromPy_LIMITED_API
(stable API).
Python 3.9.0 alpha 1¶
Release date: 2019-11-19
Security¶
bpo-38722:
runpy
now usesio.open_code()
to open code files. Patch by Jason Killen.bpo-38622: Add additional audit events for the
ctypes
module.bpo-38418: Fixes audit event for
os.system()
to be namedos.system
.bpo-38243: Escape the server title of
xmlrpc.server.DocXMLRPCServer
when rendering the document page as HTML. (Contributed by Dong-hee Na in bpo-38243.)bpo-38174: Update vendorized expat library version to 2.2.8, which resolves CVE-2019-15903.
bpo-37764: Fixes email._header_value_parser.get_unstructured going into an infinite loop for a specific case in which the email header does not have trailing whitespace, and the case in which it contains an invalid encoded word. Patch by Ashwin Ramaswami.
bpo-37461: Fix an infinite loop when parsing specially crafted email headers. Patch by Abhilash Raj.
bpo-37363: Adds audit events for the range of supported run commands (see Ligne de commande et environnement).
bpo-37463: ssl.match_hostname() no longer accepts IPv4 addresses with additional text after the address and only quad-dotted notation without trailing whitespaces. Some inet_aton() implementations ignore whitespace and all data after whitespace, e.g. '127.0.0.1 whatever'.
bpo-37363: Adds audit events for
ensurepip
,ftplib
,glob
,imaplib
,nntplib
,pdb
,poplib
,shutil
,smtplib
,sqlite3
,subprocess
,telnetlib
,tempfile
andwebbrowser
, as well asos.listdir()
,os.scandir()
andbreakpoint()
.bpo-37364:
io.open_code()
is now used when reading.pth
files.bpo-34631: Updated OpenSSL to 1.1.1c in Windows installer
bpo-34155: Fix parsing of invalid email addresses with more than one
@
(e.g. a@b@c.com.) to not return the part before 2nd@
as valid email address. Patch by maxking & jpic.
Core and Builtins¶
bpo-38631: Replace
Py_FatalError()
call with a regularRuntimeError
exception infloat.__getformat__()
.bpo-38639: Optimized
math.floor()
,math.ceil()
andmath.trunc()
for floats.bpo-38640: Fixed a bug in the compiler that was causing to raise in the presence of break statements and continue statements inside always false while loops. Patch by Pablo Galindo.
bpo-38613: Optimized some set operations (e.g.
|
,^
, and-
) ofdict_keys
.d.keys() | other
was slower thanset(d) | other
but they are almost same performance for now.bpo-28029:
"".replace("", s, n)
now returnss
instead of an empty string for all non-zeron
. There are similar changes forbytes
andbytearray
objects.bpo-38535: Fixed line numbers and column offsets for AST nodes for calls without arguments in decorators.
bpo-38525: Fix a segmentation fault when using reverse iterators of empty
dict
objects. Patch by Dong-hee Na and Inada Naoki.bpo-38465:
bytearray
,array
andmmap
objects allow now to export more than2**31
buffers at a time.bpo-38469: Fixed a bug where the scope of named expressions was not being resolved correctly in the presence of the global keyword. Patch by Pablo Galindo.
bpo-38437: Activate the
GC_DEBUG
macro for debug builds of the interpreter (whenPy_DEBUG
is set). Patch by Pablo Galindo.bpo-38379: When the garbage collector makes a collection in which some objects resurrect (they are reachable from outside the isolated cycles after the finalizers have been executed), do not block the collection of all objects that are still unreachable. Patch by Pablo Galindo and Tim Peters.
bpo-38379: When cyclic garbage collection (gc) runs finalizers that resurrect unreachable objects, the current gc run ends, without collecting any cyclic trash. However, the statistics reported by
collect()
andget_stats()
claimed that all cyclic trash found was collected, and that the resurrected objects were collected. Changed the stats to report that none were collected.bpo-38392: In debug mode,
PyObject_GC_Track()
now callstp_traverse()
of the object type to ensure that the object is valid: test that objects visited bytp_traverse()
are valid.bpo-38210: Remove unnecessary intersection and update set operation in dictview with empty set. (Contributed by Dong-hee Na in bpo-38210.)
bpo-38402: Check the error from the system's underlying
crypt
orcrypt_r
.bpo-37474: On FreeBSD, Python no longer calls
fedisableexcept()
at startup to control the floating point control mode. The call became useless since FreeBSD 6: it became the default mode.bpo-38006: Fix a bug due to the interaction of weakrefs and the cyclic garbage collector. We must clear any weakrefs in garbage in order to prevent their callbacks from executing and causing a crash.
bpo-38317: Fix warnings options priority:
PyConfig.warnoptions
has the highest priority, as stated in the PEP 587.bpo-38310: Predict
BUILD_MAP_UNPACK_WITH_CALL
->CALL_FUNCTION_EX
opcode pairs in the main interpreter loop. Patch by Brandt Bucher.bpo-36871: Improve error handling for the assert_has_calls and assert_has_awaits methods of mocks. Fixed a bug where any errors encountered while binding the expected calls to the mock's spec were silently swallowed, leading to misleading error output.
bpo-11410: Better control over symbol visibility is provided through use of the visibility attributes available in gcc >= 4.0, provided in a uniform way across POSIX and Windows. The POSIX build files have been updated to compile with -fvisibility=hidden, minimising exported symbols.
bpo-38219: Optimized the
dict
constructor and theupdate()
method for the case when the argument is a dict.bpo-38236: Python now dumps path configuration if it fails to import the Python codecs of the filesystem and stdio encodings.
bpo-38013: Allow to call
async_generator_athrow().throw(...)
even for non-started async generator helper. It fixes annoying warning at the end ofasyncio.run()
call.bpo-38124: Fix an off-by-one error in PyState_AddModule that could cause out-of-bounds memory access.
bpo-38116: The select module is now PEP-384 compliant and no longer has static state
bpo-38113: ast module updated to PEP-384 and all statics removed
bpo-38076: The struct module is now PEP-384 compatible
bpo-38075: The random module is now PEP-384 compatible
bpo-38074: zlib module made PEP-384 compatible
bpo-38073: Make pwd extension module PEP-384 compatible
bpo-38072: grp module made PEP-384 compatible
bpo-38069: Make _posixsubprocess PEP-384 compatible
bpo-38071: Make termios extension module PEP-384 compatible
bpo-38005: Fixed comparing and creating of InterpreterID and ChannelID.
bpo-36946: Fix possible signed integer overflow when handling slices. Patch by hongweipeng.
bpo-37994: Fixed silencing arbitrary errors if an attribute lookup fails in several sites. Only AttributeError should be silenced.
bpo-8425: Optimize set difference_update for the case when the other set is much larger than the base set. (Suggested by Evgeny Kapun with code contributed by Michele Orrù).
bpo-37966: The implementation of
is_normalized()
has been greatly sped up on strings that aren't normalized, by implementing the full normalization-quick-check algorithm from the Unicode standard.bpo-37947: Adjust correctly the recursion level in the symtable generation for named expressions. Patch by Pablo Galindo.
bpo-37812: The
CHECK_SMALL_INT
macro used insideObject/longobject.c
has been replaced with an explicitreturn
at each call site.bpo-37751: Fix
codecs.lookup()
to normalize the encoding name the same way thanencodings.normalize_encoding()
, except thatcodecs.lookup()
also converts the name to lower case.bpo-37830: Fixed compilation of
break
andcontinue
in thefinally
block when the correspondingtry
block containsreturn
with a non-constant value.bpo-20490: Improve import error message for partially initialized module on circular
from
imports - by Anthony Sottile.bpo-37840: Fix handling of negative indices in
sq_item
ofbytearray
. Patch by Sergey Fedoseev.bpo-37802: Slightly improve performance of
PyLong_FromUnsignedLong()
,PyLong_FromUnsignedLongLong()
andPyLong_FromSize_t()
. Patch by Sergey Fedoseev.bpo-37409: Ensure explicit relative imports from interactive sessions and scripts (having no parent package) always raise ImportError, rather than treating the current module as the package. Patch by Ben Lewis.
bpo-32912: Reverted bpo-32912: emitting
SyntaxWarning
instead ofDeprecationWarning
for invalid escape sequences in string and bytes literals.bpo-37757: PEP 572: As described in the PEP, assignment expressions now raise
SyntaxError
when their interaction with comprehension scoping results in an ambiguous target scope.The
TargetScopeError
subclass originally proposed by the PEP has been removed in favour of just raising regular syntax errors for the disallowed cases.bpo-36279: Fix potential use of uninitialized memory in
os.wait3()
.bpo-36311: Decoding bytes objects larger than 2GiB is faster and no longer fails when a multibyte characters spans a chunk boundary.
bpo-34880: The
assert
statement now works properly if theAssertionError
exception is being shadowed. Patch by Zackery Spytz.bpo-37340: Removed object cache (
free_list
) for bound method objects. Temporary bound method objects are less used than before thanks to theLOAD_METHOD
opcode and the_PyObject_VectorcallMethod
C API.bpo-37648: Fixed minor inconsistency in
list.__contains__()
,tuple.__contains__()
and a few other places. The collection's item is now always at the left and the needle is on the right of==
.bpo-37444: Update differing exception between
builtins.__import__()
andimportlib.__import__()
.bpo-37619: When adding a wrapper descriptor from one class to a different class (for example, setting
__add__ = str.__add__
on anint
subclass), an exception is correctly raised when the operator is called.bpo-37593: Swap the positions of the posonlyargs and args parameters in the constructor of
ast.parameters
nodes.bpo-37543: Optimized pymalloc for non PGO build.
bpo-37537: Compute allocated pymalloc blocks inside _Py_GetAllocatedBlocks(). This slows down _Py_GetAllocatedBlocks() but gives a small speedup to _PyObject_Malloc() and _PyObject_Free().
bpo-37467: Fix
sys.excepthook()
andPyErr_Display()
if a filename is a bytes string. For example, for a SyntaxError exception where the filename attribute is a bytes string.bpo-37433: Fix
SyntaxError
indicator printing too many spaces for multi-line strings - by Anthony Sottile.bpo-37417:
bytearray.extend()
now correctly handles errors that arise during iteration. Patch by Brandt Bucher.bpo-37414: The undocumented
sys.callstats()
function has been removed. Since Python 3.7, it was deprecated and always returnedNone
. It required a special build optionCALL_PROFILE
which was already removed in Python 3.7.bpo-37392: Remove
sys.getcheckinterval()
andsys.setcheckinterval()
functions. They were deprecated since Python 3.2. Usesys.getswitchinterval()
andsys.setswitchinterval()
instead. Remove alsocheck_interval
field of thePyInterpreterState
structure.bpo-37388: In development mode and in debug build, encoding and errors arguments are now checked on string encoding and decoding operations. Examples:
open()
,str.encode()
andbytes.decode()
.By default, for best performances, the errors argument is only checked at the first encoding/decoding error, and the encoding argument is sometimes ignored for empty strings.
bpo-37348: Optimized decoding short ASCII string with UTF-8 and ascii codecs.
b"foo".decode()
is about 15% faster. Patch by Inada Naoki.bpo-24214: Improved support of the surrogatepass error handler in the UTF-8 and UTF-16 incremental decoders.
bpo-37330:
open()
,io.open()
,codecs.open()
andfileinput.FileInput
no longer accept'U'
("universal newline") in the file mode. This flag was deprecated since Python 3.3.bpo-35224: Reverse evaluation order of key: value in dict comprehensions as proposed in PEP 572. I.e. in
{k: v for ...}
,k
will be evaluated beforev
.bpo-37316: Fix the
PySys_Audit()
call inmmap.mmap
.bpo-37300: Remove an unnecessary Py_XINCREF in classobject.c.
bpo-37269: Fix a bug in the peephole optimizer that was not treating correctly constant conditions with binary operators. Patch by Pablo Galindo.
bpo-20443: Python now gets the absolute path of the script filename specified on the command line (ex: "python3 script.py"): the __file__ attribute of the __main__ module and sys.path[0] become an absolute path, rather than a relative path.
bpo-37257: Python's small object allocator (
obmalloc.c
) now allows (no more than) one empty arena to remain available for immediate reuse, without returning it to the OS. This prevents thrashing in simple loops where an arena could be created and destroyed anew on each iteration.bpo-37231: The dispatching of type slots to special methods (for example calling
__mul__
when doingx * y
) has been made faster.bpo-36974: Implemented separate vectorcall functions for every calling convention of builtin functions and methods. This improves performance for calls.
bpo-37213: Handle correctly negative line offsets in the peephole optimizer. Patch by Pablo Galindo.
bpo-37219: Remove erroneous optimization for empty set differences.
bpo-15913: Implement
PyBuffer_SizeFromFormat()
function (previously documented but not implemented): callstruct.calcsize()
. Patch by Joannah Nanjekye.bpo-36922: Slot functions optimize any callable with
Py_TPFLAGS_METHOD_DESCRIPTOR
instead of only instances offunction
.bpo-36974: The slot
tp_vectorcall_offset
is inherited unconditionally to supportsuper().__call__()
when the base class uses vectorcall.bpo-37160:
threading.get_native_id()
now also supports NetBSD.bpo-37077: Add
threading.get_native_id()
support for AIX. Patch by M. Feltbpo-34556: Add
--upgrade-deps
to venv module. Patch by Cooper Ry Leesbpo-20523:
pdb.Pdb
supports ~/.pdbrc in Windows 7. Patch by Tim Hopper and Dan Lidral-Porter.bpo-35551: Updated encodings: - Removed the "tis260" encoding, which was an alias for the nonexistent "tactis" codec. - Added "mac_centeuro" as an alias for the mac_latin2 encoding.
bpo-19072: The
classmethod
decorator can now wrap other descriptors such as property objects. Adapted from a patch written by Graham Dumpleton.bpo-27575: Improve speed of dictview intersection by directly using set intersection logic. Patch by David Su.
bpo-30773: Prohibit parallel running of aclose() / asend() / athrow(). Fix ag_running to reflect the actual running status of the AG.
Library¶
bpo-36589: The
curses.update_lines_cols()
function now returnsNone
instead of1
on success.bpo-38807: Update
TypeError
messages foros.path.join()
to includeos.PathLike
objects as acceptable input types.bpo-38724: Add a repr for
subprocess.Popen
objects. Patch by Andrey Doroschenko.bpo-38786: pydoc now recognizes and parses HTTPS URLs. Patch by python273.
bpo-38785: Prevent asyncio from crashing if parent
__init__
is not called from a constructor of object derived fromasyncio.Future
.bpo-38723:
pdb
now usesio.open_code()
to trigger auditing events.bpo-27805: Allow opening pipes and other non-seekable files in append mode with
open()
.bpo-38438: Simplify the
argparse
usage message fornargs="*"
.bpo-38761: WeakSet is now registered as a collections.abc.MutableSet.
bpo-38716: logging: change RotatingHandler namer and rotator to class-level attributes. This stops __init__ from setting them to None in the case where a subclass defines them with eponymous methods.
bpo-38713: Add
os.P_PIDFD
constant, which may be passed toos.waitid()
to wait on a Linux process file descriptor.bpo-38692: Add
asyncio.PidfdChildWatcher
, a Linux-specific child watcher implementation that polls process file descriptors.bpo-38692: Expose the Linux
pidfd_open
syscall asos.pidfd_open()
.bpo-38602: Added constants
F_OFD_GETLK
,F_OFD_SETLK
andF_OFD_SETLKW
to thefcntl
module. Patch by Dong-hee Na.bpo-38334: Fixed seeking backward on an encrypted
zipfile.ZipExtFile
.bpo-38312: Add
curses.get_escdelay()
,curses.set_escdelay()
,curses.get_tabsize()
, andcurses.set_tabsize()
functions - by Anthony Sottile.bpo-38586: Now
fileConfig()
correctly sets the .name of handlers loaded.bpo-38565: Add new cache_parameters() method for functools.lru_cache() to better support pickling.
bpo-34679: asynci.ProactorEventLoop.close() now only calls signal.set_wakeup_fd() in the main thread.
bpo-31202: The case the result of
pathlib.WindowsPath.glob()
matches now the case of the pattern for literal parts.bpo-36321: Remove misspelled attribute. The 3.8 changelog noted that this would be removed in 3.9.
bpo-38521: Fixed erroneous equality comparison in statistics.NormalDist().
bpo-38493: Added
CLD_KILLED
andCLD_STOPPED
forsi_code
. Patch by Dong-hee Na.bpo-38478: Fixed a bug in
inspect.signature.bind()
that was causing it to fail when handling a keyword argument with same name as positional-only parameter. Patch by Pablo Galindo.bpo-33604: Fixed
hmac.new
andhmac.HMAC
to raise TypeError instead of ValueError when the digestmod parameter, now required in 3.8, is omitted. Also clarified the hmac module documentation and docstrings.bpo-38378: Parameters out and in of
os.sendfile()
was renamed to out_fd and in_fd.bpo-38417: Added support for setting the umask in the child process to the subprocess module on POSIX systems.
bpo-38449: Revert PR 15522, which introduces a regression in
mimetypes.guess_type()
due to improper handling of filenames as urls.bpo-38431: Fix
__repr__
method fordataclasses.InitVar
to support typing objects, patch by Samuel Colvin.bpo-38109: Add missing
stat.S_IFDOOR
,stat.S_IFPORT
,stat.S_IFWHT
,stat.S_ISDOOR()
,stat.S_ISPORT()
, andstat.S_ISWHT()
values to the Python implementation ofstat
.bpo-38422: Clarify docstrings of pathlib suffix(es)
bpo-38405: Nested subclasses of
typing.NamedTuple
are now pickleable.bpo-38332: Prevent
KeyError
thrown by_encoded_words.decode()
when given an encoded-word with invalid content-type encoding from propagating all the way toemail.message.get()
.bpo-38371: Deprecated the
split()
method in_tkinter.TkappType
in favour of thesplitlist()
method which has more consistent and predicable behavior.bpo-38341: Add
smtplib.SMTPNotSupportedError
to thesmtplib
exported names.bpo-38319: sendfile() used in socket and shutil modules was raising OverflowError for files >= 2GiB on 32-bit architectures. (patch by Giampaolo Rodola)
bpo-38242: Revert the new asyncio Streams API
bpo-13153: OS native encoding is now used for converting between Python strings and Tcl objects. This allows to display, copy and paste to clipboard emoji and other non-BMP characters. Converting strings from Tcl to Python and back now never fails (except MemoryError).
bpo-38019: Correctly handle pause/resume reading of closed asyncio unix pipe.
bpo-38163: Child mocks will now detect their type as either synchronous or asynchronous, asynchronous child mocks will be AsyncMocks and synchronous child mocks will be either MagicMock or Mock (depending on their parent type).
bpo-38161: Removes _AwaitEvent from AsyncMock.
bpo-38216: Allow the rare code that wants to send invalid http requests from the
http.client
library a way to do so. The fixes for bpo-30458 led to breakage for some projects that were relying on this ability to test their own behavior in the face of bad requests.bpo-28286: Deprecate opening
GzipFile
for writing implicitly. Always specify the mode argument for writing.bpo-38108: Any synchronous magic methods on an AsyncMock now return a MagicMock. Any asynchronous magic methods on a MagicMock now return an AsyncMock.
bpo-38265: Update the length parameter of
os.pread()
to acceptPy_ssize_t
instead ofint
.bpo-38112:
compileall
has a higher default recursion limit and new command-line arguments for path manipulation, symlinks handling, and multiple optimization levels.bpo-38248: asyncio: Fix inconsistent immediate Task cancellation
bpo-38237: The arguments for the builtin pow function are more descriptive. They can now also be passed in as keywords.
bpo-34002: Improve efficiency in parts of email package by changing while-pop to a for loop, using isdisjoint instead of set intersections.
bpo-38191: Constructors of
NamedTuple
andTypedDict
types now accept arbitrary keyword argument names, including "cls", "self", "typename", "_typename", "fields" and "_fields".bpo-38185: Fixed case-insensitive string comparison in
sqlite3.Row
indexing.bpo-38136: Changes AsyncMock call count and await count to be two different counters. Now await count only counts when a coroutine has been awaited, not when it has been called, and vice-versa. Update the documentation around this.
bpo-37828: Fix default mock name in
unittest.mock.Mock.assert_called()
exceptions. Patch by Abraham Toriz Cruz.bpo-38175: Fix a memory leak in comparison of
sqlite3.Row
objects.bpo-33936: _hashlib no longer calls obsolete OpenSSL initialization function with OpenSSL 1.1.0+.
bpo-34706: Preserve subclassing in inspect.Signature.from_callable.
bpo-38153: Names of hashing algorithms from OpenSSL are now normalized to follow Python's naming conventions. For example OpenSSL uses sha3-512 instead of sha3_512 or blake2b512 instead of blake2b.
bpo-38115: Fix a bug in dis.findlinestarts() where it would return invalid bytecode offsets. Document that a code object's co_lnotab can contain invalid bytecode offsets.
bpo-38148: Add slots to
asyncio
transport classes, which can reduce memory usage.bpo-38142: The _hashlib OpenSSL wrapper extension module is now PEP-384 compliant.
bpo-9216: hashlib constructors now support usedforsecurity flag to signal that a hashing algorithm is not used in a security context.
bpo-36991: Fixes a potential incorrect AttributeError exception escaping ZipFile.extract() in some unsupported input error situations.
bpo-38134: Remove obsolete copy of PBKDF2_HMAC_fast. All supported OpenSSL versions contain a fast implementation.
bpo-38132: The OpenSSL hashlib wrapper uses a simpler implementation. Several Macros and pointless caches are gone. The hash name now comes from OpenSSL's EVP. The algorithm name stays the same, except it is now always lower case.
bpo-38008: Fix parent class check in protocols to correctly identify the module that provides a builtin protocol, instead of assuming they all come from the
collections.abc
modulebpo-34037: For
asyncio
, add a new coroutineloop.shutdown_default_executor()
. The new coroutine provides an API to schedule an executor shutdown that waits on the threadpool to finish closing. Also,asyncio.run()
has been updated to utilize the new coroutine. Patch by Kyle Stanley.bpo-37405: Fixed regression bug for socket.getsockname() for non-CAN_ISOTP AF_CAN address family sockets by returning a 1-tuple instead of string.
bpo-38121: Update parameter names on functions in importlib.metadata matching the changes in the 0.22 release of importlib_metadata.
bpo-38110: The os.closewalk() implementation now uses the libc fdwalk() API on platforms where it is available.
bpo-38093: Fixes AsyncMock so it doesn't crash when used with AsyncContextManagers or AsyncIterators.
bpo-37488: Add warning to
datetime.utctimetuple()
,datetime.utcnow()
anddatetime.utcfromtimestamp()
.bpo-35640: Allow passing a path-like object as
directory
argument to thehttp.server.SimpleHTTPRequestHandler
class. Patch by Géry Ogam.bpo-38086: Update importlib.metadata with changes from importlib_metadata 0.21.
bpo-37251: Remove
__code__
check in AsyncMock that incorrectly evaluated function specs as async objects but failed to evaluate classes with__await__
but no__code__
attribute defined as async objects.bpo-38066: Hide internal asyncio.Stream methods: feed_eof(), feed_data(), set_exception() and set_transport().
bpo-38059: inspect.py now uses sys.exit() instead of exit()
bpo-37953: In
typing
, improved the__hash__
and__eq__
methods forForwardReferences
.bpo-38026: Fixed
inspect.getattr_static()
usedisinstance
while it should avoid dynamic lookup.bpo-35923: Update
importlib.machinery.BuiltinImporter
to useloader._ORIGIN
instead of a hardcoded value. Patch by Dong-hee Na.bpo-38010: In
importlib.metadata
sync withimportlib_metadata
0.20, clarifying behavior offiles()
and fixing issue where only one requirement was returned forrequires()
ondist-info
packages.bpo-38006: weakref.WeakValueDictionary defines a local remove() function used as callback for weak references. This function was created with a closure. Modify the implementation to avoid the closure.
bpo-37995: Added the indent option to
ast.dump()
which allows it to produce a multiline indented output.bpo-34410: Fixed a crash in the
tee()
iterator when re-enter it. RuntimeError is now raised in this case.bpo-37140: Fix a ctypes regression of Python 3.8. When a ctypes.Structure is passed by copy to a function, ctypes internals created a temporary object which had the side effect of calling the structure finalizer (__del__) twice. The Python semantics requires a finalizer to be called exactly once. Fix ctypes internals to no longer call the finalizer twice.
bpo-37587:
_json.scanstring
is now up to 3x faster when there are many backslash escaped characters in the JSON string.bpo-37834: Prevent shutil.rmtree exception when built on non-Windows system without fd system call support, like older versions of macOS.
bpo-10978: Semaphores and BoundedSemaphores can now release more than one waiting thread at a time.
bpo-37972: Subscripts to the
unittest.mock.call
objects now receive the same chaining mechanism as any other custom attributes, so that the following usage no longer raises aTypeError
:call().foo().__getitem__('bar')
Patch by blhsing
bpo-37965: Fix C compiler warning caused by distutils.ccompiler.CCompiler.has_function.
bpo-37960:
repr()
of buffered and text streams now silences only expected exceptions when get the value of "name" and "mode" attributes.bpo-37961: Add a
total_nframe
field to the traces collected by the tracemalloc module. This field indicates the original number of frames before it was truncated.bpo-37951: Most features of the subprocess module now work again in subinterpreters. Only preexec_fn is restricted in subinterpreters.
bpo-36205: Fix the rusage implementation of time.process_time() to correctly report the sum of the system and user CPU time.
bpo-37950: Fix
ast.dump()
when call with incompletely initialized node.bpo-34679: Restores instantiation of Windows IOCP event loops from the non-main thread.
bpo-36917: Add default implementation of the
ast.NodeVisitor.visit_Constant()
method which emits a deprecation warning and calls corresponding methodyvisit_Num()
,visit_Str()
, etc.bpo-37798: Update test_statistics.py to verify that the statistics module works well for both C and Python implementations. Patch by Dong-hee Na
bpo-26589: Added a new status code to the http module: 451 UNAVAILABLE_FOR_LEGAL_REASONS
bpo-37915: Fix a segmentation fault that appeared when comparing instances of
datetime.timezone
anddatetime.tzinfo
objects. Patch by Pablo Galindo.bpo-32554: Deprecate having random.seed() call hash on arbitrary types.
bpo-9938: Add optional keyword argument
exit_on_error
forArgumentParser
.bpo-37851: The
faulthandler
module no longer allocates its alternative stack at Python startup. Now the stack is only allocated at the first faulthandler usage.bpo-32793: Fix a duplicated debug message when
smtplib.SMTP.connect()
is called.bpo-37885: venv: Don't generate unset variable warning on deactivate.
bpo-37868: Fix dataclasses.is_dataclass when given an instance that never raises AttributeError in __getattr__. That is, an object that returns something for __dataclass_fields__ even if it's not a dataclass.
bpo-37811: Fix
socket
module'ssocket.connect(address)
function being unable to establish connection in case of interrupted system call. The problem was observed on all OSes whichpoll(2)
system call can take only non-negative integers and -1 as a timeout value.bpo-37863: Optimizations for Fraction.__hash__ suggested by Tim Peters.
bpo-21131: Fix
faulthandler.register(chain=True)
stack. faulthandler now allocates a dedicated stack ofSIGSTKSZ*2
bytes, instead of justSIGSTKSZ
bytes. Calling the previous signal handler in faulthandler signal handler uses more thanSIGSTKSZ
bytes of stack memory on some platforms.bpo-37798: Add C fastpath for statistics.NormalDist.inv_cdf() Patch by Dong-hee Na
bpo-37804: Remove the deprecated method
threading.Thread.isAlive()
. Patch by Dong-hee Na.bpo-37819: Add Fraction.as_integer_ratio() to match the corresponding methods in bool, int, float, and decimal.
bpo-14465: Add an xml.etree.ElementTree.indent() function for pretty-printing XML trees. Contributed by Stefan Behnel.
bpo-37810: Fix
difflib
?
hint in diff output when dealing with tabs. Patch by Anthony Sottile.bpo-37772: In
zipfile.Path
, when adding implicit dirs, ensure that ancestral directories are added and that duplicates are excluded.bpo-18578: Renamed and documented
test.bytecode_helper
astest.support.bytecode_helper
. Patch by Joannah Nanjekye.bpo-34488:
writelines()
method ofio.BytesIO
is now slightly faster when many small lines are passed. Patch by Sergey Fedoseev.bpo-37449:
ensurepip
now usesimportlib.resources.read_binary()
to read data instead ofpkgutil.get_data()
. Patch by Joannah Nanjekye.bpo-28292: Mark calendar.py helper functions as being private. The follows PEP 8 guidance to maintain the style conventions in the module and it addresses a known case of user confusion.
bpo-18049: Add definition of THREAD_STACK_SIZE for AIX in Python/thread_pthread.h The default thread stacksize caused crashes with the default recursion limit Patch by M Felt
bpo-37742: The logging.getLogger() API now returns the root logger when passed the name 'root', whereas previously it returned a non-root logger named 'root'. This could affect cases where user code explicitly wants a non-root logger named 'root', or instantiates a logger using logging.getLogger(__name__) in some top-level module called 'root.py'.
bpo-37738: Fix the implementation of curses
addch(str, color_pair)
: pass the color pair tosetcchar()
, instead of always passing 0 as the color pair.bpo-37723: Fix performance regression on regular expression parsing with huge character sets. Patch by Yann Vaginay.
bpo-35943: The function
PyImport_GetModule()
now ensures any module it returns is fully initialized. Patch by Joannah Nanjekye.bpo-32178: Fix IndexError in
email
package when trying to parse invalid address fields starting with:
.bpo-37268: The
parser
module is deprecated and will be removed in future versions of Python.bpo-37685: Fixed comparisons of
datetime.timedelta
anddatetime.timezone
.bpo-37697: Synchronize
importlib.metadata
with importlib_metadata 0.19, improving handling of EGG-INFO files and fixing a crash when entry point names contained colons.bpo-37695: Correct
curses.unget_wch()
error message. Patch by Anthony Sottile.bpo-37689: Add
is_relative_to()
inPurePath
to determine whether or not one path is relative to another.bpo-29553: Fixed
argparse.ArgumentParser.format_usage()
for mutually exclusive groups. Patch by Andrew Nester.bpo-37691: Let math.dist() accept coordinates as sequences (or iterables) rather than just tuples.
bpo-37685: Fixed
__eq__
,__lt__
etc implementations in some classes. They now returnNotImplemented
for unsupported type of the other operand. This allows the other operand to play role (for example the equality comparison withANY
will returnTrue
).bpo-37354: Make Activate.ps1 Powershell script static to allow for signing it.
bpo-37664: Update wheels bundled with ensurepip (pip 19.2.3 and setuptools 41.2.0)
bpo-37663: Bring consistency to venv shell activation scripts by always using __VENV_PROMPT__.
bpo-37642: Allowed the pure Python implementation of
datetime.timezone
to represent sub-minute offsets close to minimum and maximum boundaries, specifically in the ranges (23:59, 24:00) and (-23:59, 24:00). Patch by Ngalim Siregarbpo-36161: In
posix
, usettyname_r
instead ofttyname
for thread safety.bpo-36324: Make internal attributes for statistics.NormalDist() private.
bpo-37555: Fix
NonCallableMock._call_matcher
returning tuple instead of_Call
object whenself._spec_signature
exists. Patch by Elizabeth Useltonbpo-29446: Make
from tkinter import *
import only the expected objects.bpo-16970: Adding a value error when an invalid value in passed to nargs Patch by Robert Leenders
bpo-34443: Exceptions from
enum
now use the__qualname
of the enum class in the exception message instead of the__name__
.bpo-37491: Fix
IndexError
when parsing email headers with unexpectedly ending bare-quoted string value. Patch by Abhilash Raj.bpo-37587: Make json.loads faster for long strings. (Patch by Marco Paolini)
bpo-18378: Recognize "UTF-8" as a valid value for LC_CTYPE in locale._parse_localename.
bpo-37579: Return
NotImplemented
in Python implementation of__eq__
fortimedelta
andtime
when the other object being compared is not of the same type to match C implementation. Patch by Karthikeyan Singaravelan.bpo-21478: Record calls to parent when autospecced object is attached to a mock using
unittest.mock.attach_mock()
. Patch by Karthikeyan Singaravelan.bpo-37531: "python3 -m test -jN --timeout=TIMEOUT" now kills a worker process if it runs longer than TIMEOUT seconds.
bpo-37482: Fix serialization of display name in originator or destination address fields with both encoded words and special chars.
bpo-36993: Improve error reporting for corrupt zip files with bad zip64 extra data. Patch by Daniel Hillier.
bpo-37502: pickle.loads() no longer raises TypeError when the buffers argument is set to None
bpo-37520: Correct behavior for zipfile.Path.parent when the path object identifies a subdirectory.
bpo-18374: Fix the
.col_offset
attribute of nestedast.BinOp
instances which had a too large value in some situations.bpo-37424: Fixes a possible hang when using a timeout on
subprocess.run()
while capturing output. If the child process spawned its own children or otherwise connected its stdout or stderr handles with another process, we could hang after the timeout was reached and our child was killed when attempting to read final output from the pipes.bpo-37421: Fix
multiprocessing.util.get_temp_dir()
finalizer: clear also the 'tempdir' configuration of the current process, so next call toget_temp_dir()
will create a new temporary directory, rather than reusing the removed temporary directory.bpo-37481: The distutils
bdist_wininst
command is deprecated in Python 3.8, usebdist_wheel
(wheel packages) instead.bpo-37479: When
Enum.__str__
is overridden in a derived class, the override will be used byEnum.__format__
regardless of whether mixin classes are present.bpo-37440: http.client now enables TLS 1.3 post-handshake authentication for default context or if a cert_file is passed to HTTPSConnection.
bpo-37437: Update vendorized expat version to 2.2.7.
bpo-37428: SSLContext.post_handshake_auth = True no longer sets SSL_VERIFY_POST_HANDSHAKE verify flag for client connections. Although the option is documented as ignored for clients, OpenSSL implicitly enables cert chain validation when the flag is set.
bpo-37420:
os.sched_setaffinity()
now correctly handles errors that arise during iteration over itsmask
argument. Patch by Brandt Bucher.bpo-37412: The
os.getcwdb()
function now uses the UTF-8 encoding on Windows, rather than the ANSI code page: see PEP 529 for the rationale. The function is no longer deprecated on Windows.bpo-37406: The sqlite3 module now raises TypeError, rather than ValueError, if operation argument type is not str: execute(), executemany() and calling a connection.
bpo-29412: Fix IndexError in parsing a header value ending unexpectedly. Patch by Abhilash Raj.
bpo-36546: The dist argument for statistics.quantiles() is now positional only. The current name doesn't reflect that the argument can be either a dataset or a distribution. Marking the parameter as positional avoids confusion and makes it possible to change the name later.
bpo-37394: Fix a bug that was causing the
queue
module to fail if the accelerator module was not available. Patch by Pablo Galindo.bpo-37376:
pprint
now has support fortypes.SimpleNamespace
. Patch by Carl Bordum Hansen.bpo-26967: An
ArgumentParser
withallow_abbrev=False
no longer disables grouping of short flags, such as-vv
, but only disables abbreviation of long flags as documented. Patch by Zac Hatfield-Dodds.bpo-37212:
unittest.mock.call()
now preserves the order of keyword arguments in repr output. Patch by Karthikeyan Singaravelan.bpo-37372: Fix error unpickling datetime.time objects from Python 2 with seconds>=24. Patch by Justin Blanchard.
bpo-37345: Add formal support for UDPLITE sockets. Support was present before, but it is now easier to detect support with
hasattr(socket, 'IPPROTO_UDPLITE')
and there are constants defined for each of the values needed:socket.IPPROTO_UDPLITE
,UDPLITE_SEND_CSCOV
, andUDPLITE_RECV_CSCOV
. Patch by Gabe Appleton.bpo-37358: Optimized
functools.partial
by using vectorcall.bpo-37347:
sqlite3.Connection.create_aggregate()
,sqlite3.Connection.create_function()
,sqlite3.Connection.set_authorizer()
,sqlite3.Connection.set_progress_handler()
sqlite3.Connection.set_trace_callback()
methods lead to segfaults if some of these methods are called twice with an equal object but not the same. Now callbacks are stored more carefully. Patch by Aleksandr Balezin.bpo-37163: The obj argument of
dataclasses.replace()
is positional-only now.bpo-37085: Add the optional Linux SocketCAN Broadcast Manager constants, used as flags to configure the BCM behaviour, in the socket module. Patch by Karl Ding.
bpo-37328:
HTMLParser.unescape
is removed. It was undocumented and deprecated since Python 3.4.bpo-37305: Add .webmanifest -> application/manifest+json to list of recognized file types and content type headers
bpo-37320:
aifc.openfp()
alias toaifc.open()
,sunau.openfp()
alias tosunau.open()
, andwave.openfp()
alias towave.open()
have been removed. They were deprecated since Python 3.7.bpo-37315: Deprecated accepting floats with integral value (like
5.0
) inmath.factorial()
.bpo-37312:
_dummy_thread
anddummy_threading
modules have been removed. These modules were deprecated since Python 3.7 which requires threading support.bpo-33972: Email with single part but content-type set to
multipart/*
doesn't raise AttributeError anymore.bpo-37280: Use threadpool for reading from file for sendfile fallback mode.
bpo-37279: Fix asyncio sendfile support when sendfile sends extra data in fallback mode.
bpo-19865:
ctypes.create_unicode_buffer()
now also supports non-BMP characters on platforms with 16-bitwchar_t
(for example, Windows and AIX).bpo-37266: In a subinterpreter, spawning a daemon thread now raises an exception. Daemon threads were never supported in subinterpreters. Previously, the subinterpreter finalization crashed with a Python fatal error if a daemon thread was still running.
bpo-37210: Allow pure Python implementation of
pickle
to work even when the C_pickle
module is unavailable.bpo-21872: Fix
lzma
: module decompresses data incompletely. When decompressing a FORMAT_ALONE format file, and it doesn't have the end marker, sometimes the last one to dozens bytes can't be output. Patch by Ma Lin.bpo-35922: Fix
RobotFileParser.crawl_delay()
andRobotFileParser.request_rate()
to returnNone
rather than raiseAttributeError
when no relevant rule is defined in the robots.txt file. Patch by Rémi Lapeyre.bpo-35766: Change the format of feature_version to be a (major, minor) tuple.
bpo-36607: Eliminate
RuntimeError
raised byasyncio.all_tasks()
if internal tasks weak set is changed by another thread during iteration.bpo-18748:
_pyio.IOBase
destructor now does nothing if getting theclosed
attribute fails to better mimic_io.IOBase
finalizer.bpo-36402: Fix a race condition at Python shutdown when waiting for threads. Wait until the Python thread state of all non-daemon threads get deleted (join all non-daemon threads), rather than just wait until non-daemon Python threads complete.
bpo-37206: Default values which cannot be represented as Python objects no longer improperly represented as
None
in function signatures.bpo-37111: Added
encoding
anderrors
keyword parameters tologging.basicConfig
.bpo-12144: Ensure cookies with
expires
attribute are handled inCookieJar.make_cookies()
.bpo-34886: Fix an unintended ValueError from
subprocess.run()
when checking for conflictinginput
andstdin
orcapture_output
andstdout
orstderr
args when they were explicitly provided but withNone
values within a passed in**kwargs
dict rather than as passed directly by name. Patch contributed by Rémi Lapeyre.bpo-37173: The exception message for
inspect.getfile()
now correctly reports the passed class rather than the builtins module.bpo-37178: Give math.perm() a one argument form that means the same as math.factorial().
bpo-37178: For math.perm(n, k), let k default to n, giving the same result as factorial.
bpo-37165: Converted _collections._count_elements to use the Argument Clinic.
bpo-34767: Do not always create a
collections.deque
inasyncio.Lock
.bpo-37158: Speed-up statistics.fmean() by switching from a function to a generator.
bpo-34282: Remove
Enum._convert
method, deprecated in 3.8.bpo-37150:
argparse._ActionsContainer.add_argument
now throws error, if someone accidentally pass FileType class object instead of instance of FileType astype
argumentbpo-28724: The socket module now has the
socket.send_fds()
andsocket.recv.fds()
methods. Contributed by Joannah Nanjekye, Shinya Okano and Victor Stinner.bpo-35621: Support running asyncio subprocesses when execution event loop in a thread on UNIX.
bpo-36520: Lengthy email headers with UTF-8 characters are now properly encoded when they are folded. Patch by Jeffrey Kintscher.
bpo-30835: Fixed a bug in email parsing where a message with invalid bytes in content-transfer-encoding of a multipart message can cause an AttributeError. Patch by Andrew Donnellan.
bpo-31163: pathlib.Path instance's rename and replace methods now return the new Path instance.
bpo-25068:
urllib.request.ProxyHandler
now lowercases the keys of the passed dictionary.bpo-26185: Fix
repr()
on emptyZipInfo
object. Patch by Mickaël Schoentgen.bpo-21315: Email headers containing RFC2047 encoded words are parsed despite the missing whitespace, and a defect registered. Also missing trailing whitespace after encoded words is now registered as a defect.
bpo-31904: Port test_datetime to VxWorks: skip zoneinfo tests on VxWorks
bpo-35805: Add parser for Message-ID header and add it to default HeaderRegistry. This should prevent folding of Message-ID using RFC 2048 encoded words.
bpo-36871: Ensure method signature is used instead of constructor signature of a class while asserting mock object against method calls. Patch by Karthikeyan Singaravelan.
bpo-35070: posix.getgrouplist() now works correctly when the user belongs to NGROUPS_MAX supplemental groups. Patch by Jeffrey Kintscher.
bpo-31783: Fix race condition in ThreadPoolExecutor when worker threads are created during interpreter shutdown.
bpo-36582: Fix
UserString.encode()
to correctly returnbytes
rather than aUserString
instance.bpo-32424: Deprecate xml.etree.ElementTree.Element.copy() in favor of copy.copy().
Patch by Gordon P. Hemsley
bpo-36564: Fix infinite loop in email header folding logic that would be triggered when an email policy's max_line_length is not long enough to include the required markup and any values in the message. Patch by Paul Ganssle
bpo-36543: Removed methods Element.getchildren(), Element.getiterator() and ElementTree.getiterator() and the xml.etree.cElementTree module.
bpo-36409: Remove the old plistlib API deprecated in Python 3.4
bpo-36302: distutils sorts source file lists so that Extension .so files build more reproducibly by default
bpo-36250: Ignore
ValueError
fromsignal
withinteraction
in non-main thread.bpo-36046: Added
user
,group
andextra_groups
parameters to the subprocess.Popen constructor. Patch by Patrick McLean.bpo-32627: Fix compile error when
_uuid
headers conflicting included.bpo-35800: Deprecate
smtpd.MailmanProxy
ready for future removal.bpo-35168:
shlex.shlex.punctuation_chars
is now a read-only property.bpo-8538: Add support for boolean actions like
--foo
and--no-foo
to argparse. Patch contributed by Rémi Lapeyre.bpo-20504: Fixes a bug in
cgi
module when a multipart/form-data request has noContent-Length
header.bpo-25988: The abstract base classes in
collections.abc
no longer are exposed in the regularcollections
module.bpo-11122: Distutils won't check for rpmbuild in specified paths only.
bpo-34775: Division handling of PurePath now returns NotImplemented instead of raising a TypeError when passed something other than an instance of str or PurePath. Patch by Roger Aiudi.
bpo-34749:
binascii.a2b_base64()
is now up to 2 times faster. Patch by Sergey Fedoseev.bpo-34519: Add additional aliases for HP Roman 8. Patch by Michael Osipov.
bpo-28009: Fix uuid.getnode() on platforms with '.' as MAC Addr delimiter as well fix for MAC Addr format that omits a leading 0 in MAC Addr values. Currently, AIX is the only know platform with these settings. Patch by Michael Felt.
bpo-30618: Add
readlink()
. Patch by Girts Folkmanis.bpo-32498: Made
urllib.parse.unquote()
accept bytes in addition to strings. Patch by Stein Karlsen.bpo-33348: lib2to3 now recognizes expressions after
*
and**
like inf(*[] or [])
.bpo-32689: Update
shutil.move()
function to allow for Path objects to be used as source argument. Patch by Emily Morehouse and Maxwell "5.13b" McKinnon.bpo-32820: Added __format__ to IPv4 and IPv6 classes. Always outputs a fully zero- padded string. Supports b/x/n modifiers (bin/hex/native format). Native format for IPv4 is bin, native format for IPv6 is hex. Also supports '#' and '_' modifiers.
bpo-27657: Fix urllib.parse.urlparse() with numeric paths. A string like "path:80" is no longer parsed as a path but as a scheme ("path") and a path ("80").
bpo-4963: Fixed non-deterministic behavior related to mimetypes extension mapping and module reinitialization.
Documentation¶
bpo-21767: Explicitly mention abc support in functools.singledispatch
bpo-38816: Provides more details about the interaction between
fork()
and CPython's runtime, focusing just on the C-API. This includes cautions about wherefork()
should and shouldn't be called.bpo-38351: Modernize
email
examples from %-formatting to f-strings.bpo-38778: Document the fact that
RuntimeError
is raised ifos.fork()
is called in a subinterpreter.bpo-38592: Add Brazilian Portuguese to the language switcher at Python Documentation website.
bpo-38294: Add list of no-longer-escaped chars to re.escape documentation
bpo-38053: Modernized the plistlib documentation
bpo-26868: Fix example usage of
PyModule_AddObject()
to properly handle errors.bpo-36797: Fix a dead link in the distutils API Reference.
bpo-37977: Warn more strongly and clearly about pickle insecurity
bpo-37979: Added a link to dateutil.parser.isoparse in the datetime.fromisoformat documentation. Patch by Paul Ganssle
bpo-12707: Deprecate info(), geturl(), getcode() methods in favor of the headers, url, and status properties, respectively, for HTTPResponse and addinfourl. Also deprecate the code attribute of addinfourl in favor of the status attribute. Patch by Ashwin Ramaswami
bpo-37937: Mention
frame.f_trace
insys.settrace()
docs.bpo-37878: Make
PyThreadState_DeleteCurrent()
Internal.bpo-37759: Beginning edits to Whatsnew 3.8
bpo-37726: Stop recommending getopt in the tutorial for command line argument parsing and promote argparse.
bpo-32910: Remove implementation-specific behaviour of how venv's Deactivate works.
bpo-37256: Fix wording of arguments for
Request
inurllib.request
bpo-37284: Add a brief note to indicate that any new
sys.implementation
required attributes must go through the PEP process.bpo-30088: Documented that
mailbox.Maildir
constructor doesn't attempt to verify the maildir folder layout correctness. Patch by Sviatoslav Sydorenko.bpo-37521: Fix
importlib
examples to insert any newly created modules via importlib.util.module_from_spec() immediately into sys.modules instead of after calling loader.exec_module().Thanks to Benjamin Mintz for finding the bug.
bpo-37456: Slash ('/') is now part of syntax.
bpo-37487: Fix PyList_GetItem index description to include 0.
bpo-37149: Replace the dead link to the Tkinter 8.5 reference by John Shipman, New Mexico Tech, with a link to the archive.org copy.
bpo-37478: Added possible exceptions to the description of os.chdir().
bpo-34903: Documented that in
datetime.datetime.strptime()
, the leading zero in some two-digit formats is optional. Patch by Mike Gleen.bpo-36260: Add decompression pitfalls to zipfile module documentation.
bpo-37004: In the documentation for difflib, a note was added explicitly warning that the results of SequenceMatcher's ratio method may depend on the order of the input strings.
bpo-36960: Restructured the
datetime
docs in the interest of making them more user-friendly and improving readability. Patch by Brad Solomon.bpo-36487: Make C-API docs clear about what the "main" interpreter is.
bpo-23460: The documentation for decimal string formatting using the
:g
specifier has been updated to reflect the correct exponential notation cutoff point. Original patch contributed by Tuomas Suutari.bpo-35803: Document and test that
tempfile
functions may accept a path-like object for thedir
argument. Patch by Anthony Sottile.bpo-33944: Added a note about the intended use of code in .pth files.
bpo-34293: Fix the Doc/Makefile regarding PAPER environment variable and PDF builds
bpo-25237: Add documentation for tkinter modules
Tests¶
bpo-38614: Fix test_communicate() of test_asyncio.test_subprocess: use
support.LONG_TIMEOUT
(5 minutes), instead of just 1 minute.bpo-38614: Add timeout constants to
test.support
:LOOPBACK_TIMEOUT
,INTERNET_TIMEOUT
,SHORT_TIMEOUT
andLONG_TIMEOUT
.bpo-38502: test.regrtest now uses process groups in the multiprocessing mode (-jN command line option) if process groups are available: if
os.setsid()
andos.killpg()
functions are available.bpo-35998: Fix a race condition in test_asyncio.test_start_tls_server_1(). Previously, there was a race condition between the test main() function which replaces the protocol and the test ServerProto protocol which sends ANSWER once it gets HELLO. Now, only the test main() function is responsible to send data, ServerProto no longer sends data.
bpo-38470: Fix
test_compileall.test_compile_dir_maxlevels()
on Windows without long path support: only create 3 subdirectories instead of between 20 and 100 subdirectories.bpo-37531: On timeout, regrtest no longer attempts to call
popen.communicate()
again: it can hang until all child processes using stdout and stderr pipes completes. Kill the worker process and ignores its output. Change also the faulthandler timeout of the main process from 1 minute to 5 minutes, for Python slowest buildbots.bpo-38239: Fix test_gdb for Link Time Optimization (LTO) builds.
bpo-38275: test_ssl now handles disabled TLS/SSL versions better. OpenSSL's crypto policy and run-time settings are recognized and tests for disabled versions are skipped. Tests also accept more TLS minimum_versions for platforms that override OpenSSL's default with strict settings.
bpo-38271: The private keys for test_ssl were encrypted with 3DES in traditional PKCS#5 format. 3DES and the digest algorithm of PKCS#5 are blocked by some strict crypto policies. Use PKCS#8 format with AES256 encryption instead.
bpo-38270: test.support now has a helper function to check for availability of a hash digest function. Several tests are refactored avoid MD5 and use SHA256 instead. Other tests are marked to use MD5 and skipped when MD5 is disabled.
bpo-37123: Multiprocessing test test_mymanager() now also expects -SIGTERM, not only exitcode 0. BaseManager._finalize_manager() sends SIGTERM to the manager process if it takes longer than 1 second to stop, which happens on slow buildbots.
bpo-38212: Multiprocessing tests: increase test_queue_feeder_donot_stop_onexc() timeout from 1 to 60 seconds.
bpo-38117: Test with OpenSSL 1.1.1d
bpo-38018: Increase code coverage for multiprocessing.shared_memory.
bpo-37805: Add tests for json.dump(..., skipkeys=True). Patch by Dong-hee Na.
bpo-37531: Enhance regrtest multiprocess timeout: write a message when killing a worker process, catch popen.kill() and popen.wait() exceptions, put a timeout on the second call to popen.communicate().
bpo-37876: Add tests for ROT-13 codec.
bpo-36833: Added tests for PyDateTime_xxx_GET_xxx() macros of the C API of the
datetime
module. Patch by Joannah Nanjekye.bpo-37558: Fix test_shared_memory_cleaned_after_process_termination name handling
bpo-37526: Add
test.support.catch_threading_exception()
: context manager catchingthreading.Thread
exception usingthreading.excepthook()
.bpo-37421: test_concurrent_futures now explicitly stops the ForkServer instance if it's running.
bpo-37421: multiprocessing tests now stop the ForkServer instance if it's running: close the "alive" file descriptor to ask the server to stop and then remove its UNIX address.
bpo-37421: test_distutils.test_build_ext() is now able to remove the temporary directory on Windows: don't import the newly built C extension ("xx") in the current process, but test it in a separated process.
bpo-37421: test_concurrent_futures now cleans up multiprocessing to remove immediately temporary directories created by multiprocessing.util.get_temp_dir().
bpo-37421: test_winconsoleio doesn't leak a temporary file anymore: use tempfile.TemporaryFile() to remove it when the test completes.
bpo-37421: multiprocessing tests now explicitly call
_run_finalizers()
to immediately remove temporary directories created by tests.bpo-37421: urllib.request tests now call
urlcleanup()
to remove temporary files created byurlretrieve()
tests and to clear the_opener
global variable set byurlopen()
and functions calling indirectlyurlopen()
.bpo-37472: Remove
Lib/test/outstanding_bugs.py
.bpo-37199: Fix test failures when IPv6 is unavailable or disabled.
bpo-19696: Replace deprecated method "random.choose" with "random.choice" in "test_pkg_import.py".
bpo-37335: Remove no longer necessary code from c locale coercion tests
bpo-37421: Fix test_shutil to no longer leak temporary files.
bpo-37411: Fix test_wsgiref.testEnviron() to no longer depend on the environment variables (don't fail if "X" variable is set).
bpo-37400: Fix test_os.test_chown(): use os.getgroups() rather than grp.getgrall() to get groups. Rename also the test to test_chown_gid().
bpo-37359: Add --cleanup option to python3 -m test to remove
test_python_*
directories of previous failed jobs. Add "make cleantest" to runpython3 -m test --cleanup
.bpo-37362: test_gdb no longer fails if it gets an "unexpected" message on stderr: it now ignores stderr. The purpose of test_gdb is to test that python-gdb.py commands work as expected, not to test gdb.
bpo-35998: Avoid TimeoutError in test_asyncio: test_start_tls_server_1()
bpo-37278: Fix test_asyncio ProactorLoopCtrlC: join the thread to prevent leaking a running thread and leaking a reference.
bpo-37261: Fix
test.support.catch_unraisable_exception()
: its __exit__() method now ignores unraisable exception raised when clearing itsunraisable
attribute.bpo-37069: regrtest now uses
sys.unraisablehook()
to mark a test as "environment altered" (ENV_CHANGED) if it emits an "unraisable exception". Moreover, regrtest logs a warning in this case.Use
python3 -m test --fail-env-changed
to catch unraisable exceptions in tests.bpo-37252: Fix assertions in
test_close
andtest_events_mask_overflow
devpoll tests.bpo-37169: Rewrite
_PyObject_IsFreed()
unit tests.bpo-37153:
test_venv.test_multiprocessing()
now explicitly callspool.terminate()
to wait until the pool completes.bpo-34001: Make test_ssl pass with LibreSSL. LibreSSL handles minimum and maximum TLS version differently than OpenSSL.
bpo-36919: Make
test_source_encoding.test_issue2301
implementation independent. The test will work now for both CPython and IronPython.bpo-30202: Update
test.test_importlib.test_abc
to testfind_spec()
.bpo-28009: Modify the test_uuid logic to test when a program is available AND can be used to obtain a MACADDR as basis for an UUID. Patch by M. Felt
bpo-34596: Fallback to a default reason when
unittest.skip()
is uncalled. Patch by Naitree Zhu.
Build¶
bpo-38809: On Windows, build scripts will now recognize and use python.exe from an active virtual env.
bpo-38684: Fix _hashlib build when Blake2 is disabled, but OpenSSL supports it.
bpo-38468: Misc/python-config.in now uses
getvar()
for all still existingsysconfig.get_config_var()
calls. Patch by Joannah Nanjekye.bpo-37415: Fix stdatomic.h header check for ICC compiler: the ICC implementation lacks atomic_uintptr_t type which is needed by Python.
bpo-38301: In Solaris family, we must be sure to use
-D_REENTRANT
. Patch by Jesús Cea Avión.bpo-36002: Locate
llvm-profdata
andllvm-ar
binaries usingAC_PATH_TOOL
rather thanAC_PATH_TARGET_TOOL
.bpo-37936: The
.gitignore
file systematically keeps "rooted", with a non-trailing slash, all the rules that are meant to apply to files in a specific place in the repo. Previously, when the intended file to ignore happened to be at the root of the repo, we'd most often accidentally also ignore files and directories with the same name anywhere in the tree.bpo-37760: The
Tools/unicode/makeunicodedata.py
script, which is used for converting information from the Unicode Character Database into generated code and data used by the methods ofstr
and by theunicodedata
module, now handles each character's data as adataclass
with named attributes, rather than a length-18 list of different fields.bpo-37936: The
.gitignore
file no longer applies to any files that are in fact tracked in the Git repository. Patch by Greg Price.bpo-37725: Change "clean" makefile target to also clean the program guided optimization (PGO) data. Previously you would have to use "make clean" and "make profile-removal", or "make clobber".
bpo-37707: Mark some individual tests to skip when --pgo is used. The tests marked increase the PGO task time significantly and likely don't help improve optimization of the final executable.
bpo-36044: Reduce the number of unit tests run for the PGO generation task. This speeds up the task by a factor of about 15x. Running the full unit test suite is slow. This change may result in a slightly less optimized build since not as many code branches will be executed. If you are willing to wait for the much slower build, the old behavior can be restored using './configure [..] PROFILE_TASK="-m test --pgo-extended"'. We make no guarantees as to which PGO task set produces a faster build. Users who care should run their own relevant benchmarks as results can depend on the environment, workload, and compiler tool chain.
bpo-37468:
make install
no longer installswininst-*.exe
files used by distutils bdist_wininst: bdist_wininst only works on Windows.bpo-37189: Many
PyRun_XXX()
functions likePyRun_String()
were no longer exported inlibpython38.dll
by mistake. Export them again to fix the ABI compatibility.bpo-25361: Enables use of SSE2 instructions in Windows 32-bit build.
bpo-36210: Update optional extension module detection for AIX. ossaudiodev and spwd are not applicable for AIX, and are no longer reported as missing. 3rd-party packaging of ncurses (with ASIS support) conflicts with officially supported AIX curses library, so configure AIX to use libcurses.a. However, skip trying to build _curses_panel.
patch by M Felt
Windows¶
bpo-38589: Fixes HTML Help shortcut when Windows is not installed to C drive
bpo-38453: Ensure ntpath.realpath() correctly resolves relative paths.
bpo-38519: Restores the internal C headers that were missing from the nuget.org and Microsoft Store packages.
bpo-38492: Remove
pythonw.exe
dependency on the Microsoft C++ runtime.bpo-38344: Fix error message in activate.bat
bpo-38359: Ensures
pyw.exe
launcher reads correct registry key.bpo-38355: Fixes
ntpath.realpath
failing onsys.executable
.bpo-38117: Update bundled OpenSSL to 1.1.1d
bpo-38092: Reduce overhead when using multiprocessing in a Windows virtual environment.
bpo-38133: Allow py.exe launcher to locate installations from the Microsoft Store and improve display of active virtual environments.
bpo-38114: The
pip.ini
is no longer included in the Nuget package.bpo-32592: Set Windows 8 as the minimum required version for API support
bpo-36634:
os.cpu_count()
now returns active processors rather than maximum processors.bpo-36634: venv activate.bat now works when the existing variables contain double quote characters.
bpo-38081: Prevent error calling
os.path.realpath()
on'NUL'
.bpo-38087: Fix case sensitivity in test_pathlib and test_ntpath.
bpo-38088: Fixes distutils not finding vcruntime140.dll with only the v142 toolset installed.
bpo-37283: Ensure command-line and unattend.xml setting override previously detected states in Windows installer.
bpo-38030: Fixes
os.stat()
failing for block devices on Windowsbpo-38020: Fixes potential crash when calling
os.readlink()
(or indirectly throughrealpath()
) on a file that is not a supported link.bpo-37705: Improve the implementation of
winerror_to_errno()
.bpo-37549:
os.dup()
no longer fails for standard streams on Windows 7.bpo-1311: The
nul
file on Windows now returns True fromexists()
and a valid result fromos.stat()
withS_IFCHR
set.bpo-9949: Enable support for following symlinks in
os.realpath()
.bpo-37834: Treat all name surrogate reparse points on Windows in
os.lstat()
and other reparse points as regular files inos.stat()
.bpo-36266: Add the module name in the formatted error message when DLL load fail happens during module import in
_PyImport_FindSharedFuncptrWindows()
. Patch by Srinivas Nyayapati.bpo-25172: Trying to import the
crypt
module on Windows will result in anImportError
with a message explaining that the module isn't supported on Windows. On other platforms, if the underlying_crypt
module is not available, the ImportError will include a message explaining the problem.bpo-37778: Fixes the icons used for file associations to the Microsoft Store package.
bpo-37734: Fix use of registry values to launch Python from Microsoft Store app.
bpo-37702: Fix memory leak on Windows in creating an SSLContext object or running urllib.request.urlopen('https://...').
bpo-37672: Switch Windows Store package's pip to use bundled
pip.ini
instead ofPIP_USER
variable.bpo-10945: Officially drop support for creating bdist_wininst installers on non-Windows systems.
bpo-37445: Include the
FORMAT_MESSAGE_IGNORE_INSERTS
flag inFormatMessageW()
calls.bpo-37369: Fixes path for
sys.executable
when running from the Microsoft Store.bpo-37380: Don't collect unfinished processes with
subprocess._active
on Windows to cleanup later. Patch by Ruslan Kuprieiev.bpo-37351: Removes libpython38.a from standard Windows distribution.
bpo-35360: Update Windows builds to use SQLite 3.28.0.
bpo-37267: On Windows,
os.dup()
no longer creates an inheritable fd when handling a character file.bpo-36779: Ensure
time.tzname
is correct on Windows when the active code page is set to CP_UTF7 or CP_UTF8.bpo-32587: Make
winreg.REG_MULTI_SZ
support zero-length strings.bpo-28269: Replace use of
strcasecmp()
for the system function_stricmp()
. Patch by Minmin Gong.bpo-36590: Add native Bluetooth RFCOMM support to socket module.
macOS¶
bpo-38117: Updated OpenSSL to 1.1.1d in macOS installer.
bpo-38089: Move Azure Pipelines to latest VM versions and make macOS tests optional
bpo-18049: Increase the default stack size of threads from 5MB to 16MB on macOS, to match the stack size of the main thread. This avoids crashes on deep recursion in threads.
bpo-34602: Avoid test suite failures on macOS by no longer calling resource.setrlimit to increase the process stack size limit at runtime. The runtime change is no longer needed since the interpreter is being built with a larger default stack size.
bpo-35360: Update macOS installer to use SQLite 3.28.0.
bpo-34631: Updated OpenSSL to 1.1.1c in macOS installer.
IDLE¶
bpo-26353: Stop adding newline when saving an IDLE shell window.
bpo-4630: Add an option to toggle IDLE's cursor blink for shell, editor, and output windows. See Settings, General, Window Preferences, Cursor Blink. Patch by Zackery Spytz.
bpo-38598: Do not try to compile IDLE shell or output windows
bpo-36698: IDLE no longer fails when write non-encodable characters to stderr. It now escapes them with a backslash, as the regular Python interpreter. Added the
errors
field to the standard streams.bpo-35379: When exiting IDLE, catch any AttributeError. One happens when EditorWindow.close is called twice. Printing a traceback, when IDLE is run from a terminal, is useless and annoying.
bpo-38183: To avoid problems, test_idle ignores the user config directory. It no longer tries to create or access .idlerc or any files within. Users must run IDLE to discover problems with saving settings.
bpo-38077: IDLE no longer adds 'argv' to the user namespace when initializing it. This bug only affected 3.7.4 and 3.8.0b2 to 3.8.0b4.
bpo-38041: Shell restart lines now fill the window width, always start with '=', and avoid wrapping unnecessarily. The line will still wrap if the included file name is long relative to the width.
bpo-35771: To avoid occasional spurious test_idle failures on slower machines, increase the
hover_delay
in test_tooltip.bpo-37824: Properly handle user input warnings in IDLE shell. Cease turning SyntaxWarnings into SyntaxErrors.
bpo-37929: IDLE Settings dialog now closes properly when there is no shell window.
bpo-37902: Add mousewheel scrolling for IDLE module, path, and stack browsers. Patch by George Zhang.
bpo-37849: Fixed completions list appearing too high or low when shown above the current line.
bpo-36419: Refactor IDLE autocomplete and improve testing.
bpo-37748: Reorder the Run menu. Put the most common choice, Run Module, at the top.
bpo-37692: Improve highlight config sample with example shell interaction and better labels for shell elements.
bpo-37628: Settings dialog no longer expands with font size.
bpo-37627: Initialize the Customize Run dialog with the command line arguments most recently entered before. The user can optionally edit before submitting them.
bpo-33610: Fix code context not showing the correct context when first toggled on.
bpo-37530: Optimize code context to reduce unneeded background activity. Font and highlight changes now occur along with text changes instead of after a random delay.
bpo-27452: Cleanup
config.py
by inliningRemoveFile
and simplifying the handling offile
inCreateConfigHandlers
.bpo-37325: Fix tab focus traversal order for help source and custom run dialogs.
bpo-37321: Both subprocess connection error messages now refer to the 'Startup failure' section of the IDLE doc.
bpo-17535: Add optional line numbers for IDLE editor windows. Windows open without line numbers unless set otherwise in the General tab of the configuration dialog.
bpo-26806: To compensate for stack frames added by IDLE and avoid possible problems with low recursion limits, add 30 to limits in the user code execution process. Subtract 30 when reporting recursion limits to make this addition mostly transparent.
bpo-37177: Properly 'attach' search dialogs to their main window so that they behave like other dialogs and do not get hidden behind their main window.
bpo-37039: Adjust "Zoom Height" to individual screens by momentarily maximizing the window on first use with a particular screen. Changing screen settings may invalidate the saved height. While a window is maximized, "Zoom Height" has no effect.
bpo-35763: Make calltip reminder about '/' meaning positional-only less obtrusive by only adding it when there is room on the first line.
bpo-5680: Add 'Run... Customized' to the Run menu to run a module with customized settings. Any 'command line arguments' entered are added to sys.argv. One can suppress the normal Shell main module restart.
bpo-36390: Gather Format menu functions into format.py. Combine paragraph.py, rstrip.py, and format methods from editor.py.
Tools/Demos¶
bpo-38118: Update Valgrind suppression file to ignore a false alarm in
PyUnicode_Decode()
when using GCC builtin strcmp().bpo-38347: pathfix.py: Assume all files that end on '.py' are Python scripts when working recursively.
bpo-37803: pdb's
--help
and--version
long options now work.bpo-37942: Improve ArgumentClinic converter for floats.
bpo-37704: Remove
Tools/scripts/h2py.py
: use cffi to access a C API in Python.bpo-37675: 2to3 now works when run from a zipped standard library.
bpo-37034: Argument Clinic now uses the argument name on errors with keyword-only argument instead of their position. Patch contributed by Rémi Lapeyre.
bpo-37064: Add option -k to pathscript.py script: preserve shebang flags. Add option -a to pathscript.py script: add flags.
C API¶
bpo-37633: Re-export some function compatibility wrappers for macros in
pythonrun.h
.bpo-38644: Provide
Py_EnterRecursiveCall()
andPy_LeaveRecursiveCall()
as regular functions for the limited API. Previously, there were defined as macros, but these macros didn't work with the limited API which cannot accessPyThreadState.recursion_depth
field. Remove_Py_CheckRecursionLimit
from the stable ABI.bpo-38650: The global variable
PyStructSequence_UnnamedField
is now a constant and refers to a constant string.bpo-38540: Fixed possible leak in
PyArg_Parse()
and similar functions for format units"es#"
and"et#"
when the macroPY_SSIZE_T_CLEAN
is not defined.bpo-38395: Fix a crash in
weakref.proxy
objects due to incorrect lifetime management when calling some associated methods that may delete the last reference to object being referenced by the proxy. Patch by Pablo Galindo.bpo-36389: The
_PyObject_CheckConsistency()
function is now also available in release mode. For example, it can be used to debug a crash in thevisit_decref()
function of the GC.bpo-38266: Revert the removal of PyThreadState_DeleteCurrent() with documentation.
bpo-38303: Update audioop extension module to use the stable ABI (PEP-384). Patch by Tyler Kieft.
bpo-38234:
Py_SetPath()
now setssys.executable
to the program full path (Py_GetProgramFullPath()
) rather than to the program name (Py_GetProgramName()
).bpo-38234: Python ignored arguments passed to
Py_SetPath()
,Py_SetPythonHome()
andPy_SetProgramName()
: fix Python initialization to use specified arguments.bpo-38205: The
Py_UNREACHABLE()
macro now callsPy_FatalError()
.bpo-38140: Make dict and weakref offsets opaque for C heap types by passing the offsets through PyMemberDef
bpo-15088: The C function
PyGen_NeedsFinalizing
has been removed. It was not documented, tested or used anywhere within CPython after the implementation of PEP 442. Patch by Joannah Nanjekye. (Patch by Joannah Nanjekye)bpo-36763: Options added by
PySys_AddXOption()
are now handled the same way thanPyConfig.xoptions
and command line-X
options.bpo-37926: Fix a crash in
PySys_SetArgvEx(0, NULL, 0)
.bpo-37879: Fix subtype_dealloc to suppress the type decref when the base type is a C heap type
bpo-37645: Add
_PyObject_FunctionStr()
to get a user-friendly string representation of a function-like object. Patch by Jeroen Demeyer.bpo-29548: The functions
PyEval_CallObject
,PyEval_CallFunction
,PyEval_CallMethod
andPyEval_CallObjectWithKeywords
are deprecated. UsePyObject_Call()
and its variants instead.bpo-37151:
PyCFunction_Call
is now a deprecated alias ofPyObject_Call()
.bpo-37540: The vectorcall protocol now requires that the caller passes only strings as keyword names.
bpo-37207: The vectorcall protocol is now enabled for
type
objects: settp_vectorcall
to a vectorcall function to be used instead oftp_new
andtp_init
when calling the class itself.bpo-21120: Exclude Python-ast.h, ast.h and asdl.h from the limited API.
bpo-37483: Add new function
_PyObject_CallOneArg
for calling an object with one positional argument.bpo-36763: Add
PyConfig_SetWideStringList()
function.bpo-37337: Add fast functions for calling methods:
_PyObject_VectorcallMethod()
,_PyObject_CallMethodNoArgs()
and_PyObject_CallMethodOneArg()
.bpo-28805: The
METH_FASTCALL
calling convention has been documented.bpo-37221: The new function
PyCode_NewWithPosOnlyArgs()
allows to create code objects likePyCode_New()
, but with an extra posonlyargcount parameter for indicating the number of positonal-only arguments.bpo-37194: Add a new public
PyObject_CallNoArgs()
function to the C API: call a callable Python object without any arguments. It is the most efficient way to call a callback without any argument. On x86-64, for example,PyObject_CallFunctionObjArgs(func, NULL)
allocates 960 bytes on the stack per call, whereasPyObject_CallNoArgs(func)
only allocates 624 bytes per call.bpo-37170: Fix the cast on error in
PyLong_AsUnsignedLongLongMask()
.bpo-35381: Convert posixmodule.c statically allocated types
DirEntryType
andScandirIteratorType
to heap-allocated types.bpo-34331: Use singular/plural noun in error message when instantiating an abstract class with non-overriden abstract method(s).
Python 3.8.0 beta 1¶
Release date: 2019-06-04
Security¶
bpo-35907: CVE-2019-9948: Avoid file reading by disallowing
local-file://
andlocal_file://
URL schemes inURLopener().open()
andURLopener().retrieve()
ofurllib.request
.bpo-33529: Prevent fold function used in email header encoding from entering infinite loop when there are too many non-ASCII characters in a header.
bpo-33164: Updated blake2 implementation which uses secure memset implementation provided by platform.
Core and Builtins¶
bpo-35814: Allow unpacking in the right hand side of annotated assignments. In particular,
t: Tuple[int, ...] = x, y, *z
is now allowed.bpo-37126: All structseq objects are now tracked by the garbage collector. Patch by Pablo Galindo.
bpo-37122: Make the co_argcount attribute of code objects represent the total number of positional arguments (including positional-only arguments). The value of co_posonlyargcount can be used to distinguish which arguments are positional only, and the difference (co_argcount - co_posonlyargcount) is the number of positional-or-keyword arguments. Patch by Pablo Galindo.
bpo-20092: Constructors of
int
,float
andcomplex
will now use the__index__()
special method, if available and the corresponding method__int__()
,__float__()
or__complex__()
is not available.bpo-37087: Add native thread ID (TID) support to OpenBSD.
bpo-26219: Implemented per opcode cache mechanism and
LOAD_GLOBAL
instruction use it.LOAD_GLOBAL
is now about 40% faster. Contributed by Yury Selivanov, and Inada Naoki.bpo-37072: Fix crash in PyAST_FromNodeObject() when flags is NULL.
bpo-37029: Freeing a great many small objects could take time quadratic in the number of arenas, due to using linear search to keep
obmalloc.c
's list of usable arenas sorted by order of number of free memory pools. This is accomplished without search now, leaving the worst-case time linear in the number of arenas. For programs where this quite visibly matters (typically with more than 100 thousand small objects alive simultaneously), this can greatly reduce the time needed to release their memory.bpo-26423: Fix possible overflow in
wrap_lenfunc()
whensizeof(long) < sizeof(Py_ssize_t)
(e.g., 64-bit Windows).bpo-37050: Improve the AST for "debug" f-strings, which use '=' to print out the source of the expression being evaluated. Delete expr_text from the FormattedValue node, and instead use a Constant string node (possibly merged with adjacent constant expressions inside the f-string).
bpo-22385: The
bytes.hex
,bytearray.hex
, andmemoryview.hex
methods as well as thebinascii.hexlify
andb2a_hex
functions now have the ability to include an optional separator between hex bytes. This functionality was inspired by MicroPython's hexlify implementation.bpo-26836: Add
os.memfd_create()
.bpo-37032: Added new
replace()
method to the code type (types.CodeType
).bpo-37007: Implement
socket.if_nameindex()
,socket.if_nametoindex()
, andsocket.if_indextoname()
on Windows.bpo-36829:
PyErr_WriteUnraisable()
now creates a traceback object if there is no current traceback. Moreover, callPyErr_NormalizeException()
andPyException_SetTraceback()
to normalize the exception value. Ignore any error.bpo-36878: Only accept text after
# type: ignore
if the first character is ASCII. This is to disallow things like# type: ignoreé
.bpo-36878: Store text appearing after a
# type: ignore
comment in the AST. For example a type ignore like# type: ignore[E1000]
will have the string"[E1000]"
stored in its AST node.bpo-2180: Treat line continuation at EOF as a
SyntaxError
by Anthony Sottile.bpo-36907: Fix a crash when calling a C function with a keyword dict (
f(**kwargs)
) and changing the dictkwargs
while that function is running.bpo-36946: Fix possible signed integer overflow when handling slices.
bpo-36826: Add NamedExpression kind support to ast_unparse.c
bpo-1875: A
SyntaxError
is now raised if a code blocks that will be optimized away (e.g. if conditions that are always false) contains syntax errors. Patch by Pablo Galindo.bpo-36027: Allow computation of modular inverses via three-argument
pow
: the second argument is now permitted to be negative in the case where the first and third arguments are relatively prime.bpo-36861: Update the Unicode database to version 12.1.0.
bpo-28866: Avoid caching attributes of classes which type defines mro() to avoid a hard cache invalidation problem.
bpo-36851: The
FrameType
stack is now correctly cleaned up if the execution ends with a return and the stack is not empty.bpo-34616: The
compile()
builtin functions now support theast.PyCF_ALLOW_TOP_LEVEL_AWAIT
flag, which allow to compile sources that contains top-levelawait
,async with
orasync for
. This is useful to evaluate async-code from with an already async functions; for example in a custom REPL.bpo-36842: Implement PEP 578, adding sys.audit, io.open_code and related APIs.
bpo-27639: Correct return type for UserList slicing operations. Patch by Michael Blahay, Erick Cervantes, and vaultah