核心与内置函数

• gh-102192 [https://github.com/python/cpython/issues/102192]: Deprecated PyErrChainExceptions in favour of PyErrChainExceptions1.

• gh-89987 [https://github.com/python/cpython/issues/89987]: Reduce the number of inline CACHE entries for BINARY_SUBSCR.

• gh-102859 [https://github.com/python/cpython/issues/102859]: Removed JUMP_IF_FALSE_OR_POP and JUMP_IF_TRUE_OR_POP instructions.

• gh-101975 [https://github.com/python/cpython/issues/101975]: Fixed stacktop value on tracing entries to avoid corruption on garbage collection.

• gh-102778 [https://github.com/python/cpython/issues/102778]: Add sys.last_exc and deprecate sys.last_type, sys.last_value and sys.last_traceback, which hold the same information in its legacy form.

• gh-100982 [https://github.com/python/cpython/issues/100982]: Replace all occurrences of COMPARE_AND_BRANCH with COMPARE_OP.

• gh-102701 [https://github.com/python/cpython/issues/102701]: Fix overflow when creating very large dict.

• gh-102755 [https://github.com/python/cpython/issues/102755]: Add PyErr_DisplayException() which takes just an exception instance, to replace the legacy PyErr_Display() which takes the (typ, exc, tb) triplet.

• gh-102594 [https://github.com/python/cpython/issues/102594]: Add note to exception raised in PyErr_SetObject when normalization fails.

• gh-90997 [https://github.com/python/cpython/issues/90997]: Shrink the number of inline CACHE entries used by LOAD_GLOBAL.

• gh-102491 [https://github.com/python/cpython/issues/102491]: Improve import time of platform by removing IronPython version parsing. The IronPython version parsing was not functional (see https://github.com/IronLanguages/ironpython3/issues/1667).

• gh-101291 [https://github.com/python/cpython/issues/101291]: Rearrage bits in first field (after header) of PyLongObject. Bits 0 and 1: 1 - sign. I.e. 0 for positive numbers, 1 for zero and 2 for negative numbers. Bit 2 reserved (probably for the immortal bit) * Bits 3+ the unsigned size.

This makes a few operations slightly more efficient, and will enable a more compact and faster 2s-complement representation of most ints in future.

• gh-102397 [https://github.com/python/cpython/issues/102397]: Fix segfault from race condition in signal handling during garbage collection. Patch by Kumar Aditya.

• gh-102406 [https://github.com/python/cpython/issues/102406]: codecs encoding/decoding errors now get the context information (which operation and which codecs) attached as PEP 678 [https://peps.python.org/pep-0678/] notes instead of through chaining a new instance of the exception.

• gh-102281 [https://github.com/python/cpython/issues/102281]: Fix potential nullptr dereference and use of uninitialized memory in fileutils. Patch by Max Bachmann.

• gh-102300 [https://github.com/python/cpython/issues/102300]: Reuse operands with refcount of 1 in float specializations of BINARY_OP.

• gh-102213 [https://github.com/python/cpython/issues/102213]: Fix performance loss when accessing an object's attributes with __getattr__ defined.

• gh-102255 [https://github.com/python/cpython/issues/102255]: Improve build support for the Xbox. Patch by Max Bachmann.

• gh-102027 [https://github.com/python/cpython/issues/102027]: Fix SSE2 and SSE3 detection in _blake2 internal module. Patch by Max Bachmann.

• gh-101865 [https://github.com/python/cpython/issues/101865]: Deprecate co_lnotab in code objects, schedule it for removal in Python 3.14

• bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Adapt _pickle to PEP 687 [https://peps.python.org/pep-0687/]. Patch by Mohamed Koubaa and Erlend Aasland.

库

• gh-103085 [https://github.com/python/cpython/issues/103085]: Pure python locale.getencoding() will not warn deprecation.

• gh-103068 [https://github.com/python/cpython/issues/103068]: It's no longer possible to register conditional breakpoints in Pdb that raise SyntaxError. Patch by Tian Gao.

• gh-102549 [https://github.com/python/cpython/issues/102549]: Don't ignore exceptions in member type creation.

• gh-103056 [https://github.com/python/cpython/issues/103056]: Ensure final generatenext_value_ is a staticmethod.

• gh-103046 [https://github.com/python/cpython/issues/103046]: Display current line label correctly in dis when show_caches is False and lasti points to a CACHE entry.

• gh-102433 [https://github.com/python/cpython/issues/102433]: isinstance() checks against runtime-checkable protocols now use inspect.getattr_static() rather than hasattr() to lookup whether attributes exist. This means that descriptors and __getattr__() methods are no longer unexpectedly evaluated during isinstance() checks against runtime-checkable protocols. However, it may also mean that some objects which used to be considered instances of a runtime-checkable protocol may no longer be considered instances of that protocol on Python 3.12+, and vice versa. Most users are unlikely to be affected by this change. Patch by Alex Waygood.

• gh-103023 [https://github.com/python/cpython/issues/103023]: It's no longer possible to register expressions to display in Pdb that raise SyntaxError. Patch by Tian Gao.

• gh-102947 [https://github.com/python/cpython/issues/102947]: Improve traceback when dataclasses.fields() is called on a non-dataclass. Patch by Alex Waygood

• gh-102780 [https://github.com/python/cpython/issues/102780]: The asyncio.Timeout context manager now works reliably even when performing cleanup due to task cancellation. Previously it could raise a CancelledError instead of an TimeoutError in such cases.

• gh-102871 [https://github.com/python/cpython/issues/102871]: Remove support for obsolete browsers from webbrowser. Removed browsers include Grail, Mosaic, Netscape, Galeon, Skipstone, Iceape, Firebird, and Firefox versions 35 and below.

• gh-102839 [https://github.com/python/cpython/issues/102839]: Improve performance of math.log() arguments handling by removing the argument clinic.

• gh-102828 [https://github.com/python/cpython/issues/102828]: Add the onexc arg to shutil.rmtree(), which is like onerror but expects an exception instance rather than an exc_info tuple. Deprecate onerror.

• gh-88965 [https://github.com/python/cpython/issues/88965]: typing: Fix a bug relating to substitution in custom classes generic over a ParamSpec. Previously, if the ParamSpec was substituted with a parameters list that itself contained a TypeVar, the TypeVar in the parameters list could not be subsequently substituted. This is now fixed.

Patch by Nikita Sobolev.

• gh-76846 [https://github.com/python/cpython/issues/76846]: Fix issue where _new_() and __init__() methods of pathlib.PurePath and Path subclasses were not called in some circumstances.

• gh-78530 [https://github.com/python/cpython/issues/78530]: asyncio.wait() now accepts generators yielding tasks. Patch by Kumar Aditya.

• gh-102748 [https://github.com/python/cpython/issues/102748]: asyncio.iscoroutine() now returns False for generators as asyncio does not support legacy generator-based coroutines. Patch by Kumar Aditya.

• gh-102670 [https://github.com/python/cpython/issues/102670]: Optimized fmean(), correlation(), covariance(), and linear_regression() using the new math.sumprod() function.

• gh-102615 [https://github.com/python/cpython/issues/102615]: Typing: Improve the repr of generic aliases for classes generic over a ParamSpec. (Use square brackets to represent a parameter list.)

• gh-100112 [https://github.com/python/cpython/issues/100112]: asyncio.Task.get_coro() now always returns a coroutine when wrapping an awaitable object. Patch by Kumar Aditya.

• gh-102578 [https://github.com/python/cpython/issues/102578]: Speed up setting or deleting mutable attributes on non-dataclass subclasses of frozen dataclasses. Due to the implementation of __setattr__ and __delattr__ for frozen dataclasses, this previously had a time complexity of O(n). It now has a time complexity of O(1).

• gh-102519 [https://github.com/python/cpython/issues/102519]: Add os.listdrives(), os.listvolumes() and os.listmounts() functions on Windows for enumerating drives, volumes and mount points

• gh-74468 [https://github.com/python/cpython/issues/74468]: Attribute name of the extracted tarfile file object now holds filename of itself rather than of the archive it is contained in. Patch by Oleg Iarygin.

• gh-102378 [https://github.com/python/cpython/issues/102378]: Private helper method inspect.signaturestrip_non_python_syntax will no longer strip / from the input string.

• gh-79940 [https://github.com/python/cpython/issues/79940]: Add inspect.getasyncgenstate() and inspect.getasyncgenlocals(). Patch by Thomas Krennwallner.

• gh-102103 [https://github.com/python/cpython/issues/102103]: Add module argument to dataclasses.make_dataclass() and make classes produced by it pickleable.

• gh-102069 [https://github.com/python/cpython/issues/102069]: Fix __weakref__ descriptor generation for custom dataclasses.

• gh-102038 [https://github.com/python/cpython/issues/102038]: Skip a stat in site if we have already found a pyvenv.cfg

• gh-98886 [https://github.com/python/cpython/issues/98886]: Fix issues when defining dataclasses that have fields with specific underscore names that aren't clearly reserved by dataclasses.

• gh-101673 [https://github.com/python/cpython/issues/101673]: Fix a pdb bug where ll clears the changes to local variables.

• gh-101313 [https://github.com/python/cpython/issues/101313]: Added -h and —help arguments to the webbrowser CLI

• gh-100372 [https://github.com/python/cpython/issues/100372]: ssl.SSLContext.load_verify_locations() no longer incorrectly accepts some cases of trailing data when parsing DER.

• gh-89727 [https://github.com/python/cpython/issues/89727]: Fix pathlib.Path.walk RecursionError on deep directory trees by rewriting it using iteration instead of recursion.

• gh-100131 [https://github.com/python/cpython/issues/100131]: Added an optional delete keyword argument to tempfile.TemporaryDirectory.

• gh-48330 [https://github.com/python/cpython/issues/48330]: Added --durations command line option, showing the N slowest test cases. unittest.TextTestRunner and unittest.TextTestResult constructors accept a new durations keyword argument. Subclasses should take this into account or accept **kwargs. Added unittest.TestResult.addDuration() method and unittest.TestResult.collectedDurations attribute.

(Contributed by Giampaolo Rodola)

• gh-98169 [https://github.com/python/cpython/issues/98169]: Fix dataclasses.astuple() crash when collections.defaultdict is present in the attributes.

• gh-96931 [https://github.com/python/cpython/issues/96931]: Fix incorrect results from ssl.SSLSocket.shared_ciphers()

• gh-95495 [https://github.com/python/cpython/issues/95495]: When built against OpenSSL 3.0, the ssl module had a bug where it reported unauthenticated EOFs (i.e. without close_notify) as a clean TLS-level EOF. It now raises SSLEOFError, matching the behavior in previous versions of OpenSSL. The options attribute on SSLContext also no longer includes OP_IGNORE_UNEXPECTED_EOF by default. This option may be set to specify the previous OpenSSL 3.0 behavior.

• gh-94684 [https://github.com/python/cpython/issues/94684]: Now uuid.uuid3() and uuid.uuid5() functions support bytes objects as their name argument.

• gh-94440 [https://github.com/python/cpython/issues/94440]: Fix a concurrent.futures.process bug where ProcessPoolExecutor shutdown could hang after a future has been quickly submitted and canceled.

• gh-72346 [https://github.com/python/cpython/issues/72346]: Added deprecation warning to isdst parameter of email.utils.localtime().

• bpo-36305 [https://bugs.python.org/issue?@action=redirect&bpo=36305]: Fix handling of Windows filenames that resemble drives, such as ./a:b, in pathlib.

文档

• gh-103112 [https://github.com/python/cpython/issues/103112]: Add docstring to http.client.HTTPResponse.read() to fix pydoc output.

测试

• gh-102980 [https://github.com/python/cpython/issues/102980]: Improve test coverage on pdb.

• gh-102537 [https://github.com/python/cpython/issues/102537]: Adjust the error handling strategy in test_zoneinfo.TzPathTest.python_tzpath_context. Patch by Paul Ganssle.

• gh-101377 [https://github.com/python/cpython/issues/101377]: Improved test_locale_calendar_formatweekday of calendar.

构建

• gh-102973 [https://github.com/python/cpython/issues/102973]: Add a dev container (along with accompanying Dockerfile) for development purposes.

• gh-102711 [https://github.com/python/cpython/issues/102711]: Fix -Wstrict-prototypes compiler warnings.

Windows

• gh-102690 [https://github.com/python/cpython/issues/102690]: Update webbrowser to fall back to Microsoft Edge instead of Internet Explorer.

• gh-99726 [https://github.com/python/cpython/issues/99726]: Improves correctness of stat results for Windows, and uses faster API when available

工具/示例

• gh-102809 [https://github.com/python/cpython/issues/102809]: Misc/gdbinit was removed.

C API

• gh-102013 [https://github.com/python/cpython/issues/102013]: Add a new (unstable) C-API function for iterating over GC'able objects using a callback: PyUnstable_VisitObjects.

Python 3.12.0 alpha 6

Release date: 2023-03-07

安全性

• gh-99108 [https://github.com/python/cpython/issues/99108]: Replace builtin hashlib implementations of MD5 and SHA1 with verified ones from the HACL* project.

• gh-101727 [https://github.com/python/cpython/issues/101727]: Updated the OpenSSL version used in Windows and macOS binary release builds to 1.1.1t to address CVE 2023-0286 [https://www.cve.org/CVERecord?id=CVE-2023-0286], CVE 2022-4303 [https://www.cve.org/CVERecord?id=CVE-2022-4303], and CVE 2022-4303 [https://www.cve.org/CVERecord?id=CVE-2022-4303] per the OpenSSL 2023-02-07 security advisory [https://openssl-library.org/news/secadv/20230207.txt].

• gh-99108 [https://github.com/python/cpython/issues/99108]: Replace the builtin hashlib implementations of SHA2-384 and SHA2-512 originally from LibTomCrypt with formally verified, side-channel resistant code from the HACL* [https://github.com/hacl-star/hacl-star/] project. The builtins remain a fallback only used when OpenSSL does not provide them.

• gh-101283 [https://github.com/python/cpython/issues/101283]: subprocess.Popen now uses a safer approach to find cmd.exe when launching with shell=True. Patch by Eryk Sun, based on a patch by Oleg Iarygin.

核心与内置函数

• gh-102493 [https://github.com/python/cpython/issues/102493]: Fix regression in semantics of normalisation in PyErr_SetObject.

• gh-102416 [https://github.com/python/cpython/issues/102416]: Do not memoize incorrectly automatically generated loop rules in the parser. Patch by Pablo Galindo.

• gh-102356 [https://github.com/python/cpython/issues/102356]: Fix a bug that caused a crash when deallocating deeply nested filter objects. Patch by Marta Gómez Macías.

• gh-102336 [https://github.com/python/cpython/issues/102336]: Cleanup Windows 7 specific special handling. Patch by Max Bachmann.

• gh-102250 [https://github.com/python/cpython/issues/102250]: Fixed a segfault occurring when the interpreter calls a __bool__ method that raises.

• gh-102126 [https://github.com/python/cpython/issues/102126]: Fix deadlock at shutdown when clearing thread states if any finalizer tries to acquire the runtime head lock. Patch by Kumar Aditya.

• gh-102027 [https://github.com/python/cpython/issues/102027]: Use GetCurrentProcessId on Windows when getpid is unavailable. Patch by Max Bachmann.

• gh-102056 [https://github.com/python/cpython/issues/102056]: Fix error handling bugs in interpreter's exception printing code, which could cause a crash on infinite recursion.

• gh-100982 [https://github.com/python/cpython/issues/100982]: Restrict the scope of the FOR_ITER_RANGE instruction to the scope of the original FOR_ITER instruction, to allow instrumentation.

• gh-101967 [https://github.com/python/cpython/issues/101967]: Fix possible segfault in positional_only_passedaskeyword function, when new list created.

• gh-101952 [https://github.com/python/cpython/issues/101952]: Fix possible segfault in BUILD_SET opcode, when new set created.

• gh-74895 [https://github.com/python/cpython/issues/74895]: socket.getaddrinfo no longer raises OverflowError for int port values outside of the C long range. Out of range values are left up to the underlying string based C library API to report. A socket.gaierror SAI_SERVICE may occur instead, or no error at all as not all platform C libraries generate an error.

• gh-101799 [https://github.com/python/cpython/issues/101799]: Add CALL_INTRINSIC_2 and use it instead of PREP_RERAISE_STAR.

• gh-101857 [https://github.com/python/cpython/issues/101857]: Fix xattr support detection on Linux systems by widening the check to linux, not just glibc. This fixes support for musl.

• gh-84783 [https://github.com/python/cpython/issues/84783]: Make the slice object hashable. Patch by Will Bradshaw and Furkan Onder.

• gh-87849 [https://github.com/python/cpython/issues/87849]: Change the SEND instruction to leave the receiver on the stack. This allows the specialized form of SEND to skip the chain of C calls and jump directly to the RESUME in the generator or coroutine.

• gh-101765 [https://github.com/python/cpython/issues/101765]: Fix SystemError / segmentation fault in iter __reduce__ when internal access of builtins.__dict__ keys mutates the iter object.

• gh-101430 [https://github.com/python/cpython/issues/101430]: Update tracemalloc to handle presize of object properly. Patch by Donghee Na.

• gh-101696 [https://github.com/python/cpython/issues/101696]: Invalidate type version tag in PyStaticTypeDealloc for static types, avoiding bug where a false cache hit could crash the interpreter. Patch by Kumar Aditya.

• gh-101632 [https://github.com/python/cpython/issues/101632]: Adds a new RETURN_CONST instruction.

• gh-100719 [https://github.com/python/cpython/issues/100719]: Remove gi_code field from generator (and coroutine and async generator) objects as it is redundant. The frame already includes a reference to the code object.

• gh-98627 [https://github.com/python/cpython/issues/98627]: When an interpreter is configured to check (and only then), importing an extension module will now fail when the extension does not support multiple interpreters (i.e. doesn't implement PEP 489 multiphase init). This does not apply to the main interpreter, nor to subinterpreters created with Py_NewInterpreter().

库

• gh-102302 [https://github.com/python/cpython/issues/102302]: Micro-optimise hashing of inspect.Parameter, reducing the time it takes to hash an instance by around 40%.

• gh-101979 [https://github.com/python/cpython/issues/101979]: Fix a bug where parentheses in the metavar argument to argparse.ArgumentParser.add_argument() were dropped. Patch by Yeojin Kim.

• gh-91038 [https://github.com/python/cpython/issues/91038]: platform.platform() now has boolean default arguments.

• gh-81652 [https://github.com/python/cpython/issues/81652]: Add mmap.MAP_ALIGNED_SUPER FreeBSD and mmap.MAP_CONCEAL OpenBSD constants to mmap. Patch by Yeojin Kim.

• gh-102179 [https://github.com/python/cpython/issues/102179]: Fix os.dup2() error message for negative fds.

• gh-101961 [https://github.com/python/cpython/issues/101961]: For the binary mode, fileinput.hookcompressed() doesn't set the encoding value even if the value is None. Patch by Gihwan Kim.

• gh-101936 [https://github.com/python/cpython/issues/101936]: The default value of fp becomes io.BytesIO if HTTPError is initialized without a designated fp parameter. Patch by Long Vo.

• gh-101566 [https://github.com/python/cpython/issues/101566]: In zipfile, sync Path with zipp 3.14 [https://zipp.readthedocs.io/en/latest/history.html#v3-14-0], including fix for extractall on the underlying zipfile after being wrapped in Path.

• gh-97930 [https://github.com/python/cpython/issues/97930]: Apply changes from importlib_resources 5.12 [https://importlib-resources.readthedocs.io/en/latest/history.html#v5-12-0], including fix for MultiplexedPath to support directories in multiple namespaces (python/importlib_resources#265).

• gh-101997 [https://github.com/python/cpython/issues/101997]: Upgrade pip wheel bundled with ensurepip (pip 23.0.1)

• gh-99108 [https://github.com/python/cpython/issues/99108]: The builtin extension modules for hashlib SHA2 algorithms, used when OpenSSL does not provide them, now live in a single internal _sha2 module instead of separate _sha256 and _sha512 modules.

• gh-101892 [https://github.com/python/cpython/issues/101892]: Callable iterators no longer raise SystemError when the callable object exhausts the iterator but forgets to either return a sentinel value or raise StopIteration.

• gh-87634 [https://github.com/python/cpython/issues/87634]: Remove locking behavior from functools.cached_property().

• gh-97786 [https://github.com/python/cpython/issues/97786]: Fix potential undefined behaviour in corner cases of floating-point-to-time conversions.

• gh-101517 [https://github.com/python/cpython/issues/101517]: Fixed bug where bdb looks up the source line with linecache with a lineno=None, which causes it to fail with an unhandled exception.

• gh-101773 [https://github.com/python/cpython/issues/101773]: Optimize fractions.Fraction for small components. The private argument _normalize of the fractions.Fraction constructor has been removed.

• gh-101693 [https://github.com/python/cpython/issues/101693]: In sqlite3.Cursor.execute(), DeprecationWarning is now emitted when named placeholders are used together with parameters supplied as a sequence instead of as a dict. Starting from Python 3.14, using named placeholders with parameters supplied as a sequence will raise a ProgrammingError. Patch by Erlend E. Aasland.

• gh-101446 [https://github.com/python/cpython/issues/101446]: Change repr of collections.OrderedDict to use regular dictionary formatting instead of pairs of keys and values.

• gh-101362 [https://github.com/python/cpython/issues/101362]: Speed up pathlib.PurePath construction by handling arguments more uniformly. When a pathlib.Path argument is supplied, we use its string representation rather than joining its parts with os.path.join().

• gh-101362 [https://github.com/python/cpython/issues/101362]: Speed up pathlib.PurePath construction by calling os.path.join() only when two or more arguments are given.

• gh-101362 [https://github.com/python/cpython/issues/101362]: Speed up pathlib.Path construction by running the path flavour compatibility check only when pathlib is imported.

• gh-85984 [https://github.com/python/cpython/issues/85984]: Refactored the implementation of pty.fork() to use os.login_tty().

A DeprecationWarning is now raised by pty.master_open() and pty.slave_open(). They were undocumented and deprecated long long ago in the docstring in favor of pty.openpty().

• gh-101561 [https://github.com/python/cpython/issues/101561]: Add a new decorator typing.override(). See PEP 698 [https://peps.python.org/pep-0698/] for details. Patch by Steven Troxler.

• gh-63301 [https://github.com/python/cpython/issues/63301]: Set exit code when tabnanny CLI exits on error.

• gh-101360 [https://github.com/python/cpython/issues/101360]: Fix anchor matching in pathlib.PureWindowsPath.match(). Path and pattern anchors are now matched with fnmatch, just like other path parts. This allows patterns such as ":/Users/" to be matched.

• gh-101277 [https://github.com/python/cpython/issues/101277]: Remove global state from itertools module ( PEP 687 [https://peps.python.org/pep-0687/]). Patches by Erlend E. Aasland.

• gh-100809 [https://github.com/python/cpython/issues/100809]: Fix handling of drive-relative paths (like 'C:' and 'C:foo') in pathlib.Path.absolute(). This method now uses the OS API to retrieve the correct current working directory for the drive.

• gh-99138 [https://github.com/python/cpython/issues/99138]: Apply PEP 687 [https://peps.python.org/pep-0687/] to zoneinfo. Patch by Erlend E. Aasland.

• gh-96764 [https://github.com/python/cpython/issues/96764]: asyncio.wait_for() now uses asyncio.timeout() as its underlying implementation. Patch by Kumar Aditya.

• gh-88233 [https://github.com/python/cpython/issues/88233]: Correctly preserve "extra" fields in zipfile regardless of their ordering relative to a zip64 "extra."

• bpo-23224 [https://bugs.python.org/issue?@action=redirect&bpo=23224]: Fix segfaults when creating lzma.LZMADecompressor and bz2.BZ2Decompressor objects without calling __init__(), and fix leakage of locks and internal buffers when calling the __init__() methods of lzma.LZMADecompressor, lzma.LZMACompressor, bz2.BZ2Compressor, and bz2.BZ2Decompressor objects multiple times.

文档

• gh-85417 [https://github.com/python/cpython/issues/85417]: Update cmath documentation to clarify behaviour on branch cuts.

• gh-97725 [https://github.com/python/cpython/issues/97725]: Fix asyncio.Task.print_stack() description for file=None. Patch by Oleg Iarygin.

测试

• gh-102019 [https://github.com/python/cpython/issues/102019]: Fix deadlock on shutdown if test_current_{exception,frames} fails. Patch by Jacob Bower.

• gh-85984 [https://github.com/python/cpython/issues/85984]: Utilize new "winsize" functions from termios in pty tests.

• gh-89792 [https://github.com/python/cpython/issues/89792]: test_tools now copies up to 10x less source data to a temporary directory during the freeze test by ignoring git metadata and other artifacts. It also limits its python build parallelism based on os.cpu_count instead of hard coding it as 8 cores.

构建

• gh-99942 [https://github.com/python/cpython/issues/99942]: On Android, in a static build, python-config in embed mode no longer incorrectly reports a library to link to.

• gh-99942 [https://github.com/python/cpython/issues/99942]: On Android, python.pc now correctly reports the library to link to, the same as python-config.sh.

• gh-100221 [https://github.com/python/cpython/issues/100221]: Fix creating install directories in make sharedinstall if they exist outside DESTDIR already.

• gh-96821 [https://github.com/python/cpython/issues/96821]: Explicitly mark C extension modules that need defined signed integer overflow, and add a configure option --with-strict-overflow. Patch by Matthias Görgens and Shantanu Jain.

Windows

• gh-102344 [https://github.com/python/cpython/issues/102344]: Implement winreg.QueryValue using QueryValueEx and winreg.SetValue using SetValueEx. Patch by Max Bachmann.

• gh-101881 [https://github.com/python/cpython/issues/101881]: Handle read and write operations on nonblocking pipes properly on Windows.

• gh-101881 [https://github.com/python/cpython/issues/101881]: Add support for the os.get_blocking() and os.set_blocking() functions on Windows.

• gh-101849 [https://github.com/python/cpython/issues/101849]: Ensures installer will correctly upgrade existing py.exe launcher installs.

• gh-101763 [https://github.com/python/cpython/issues/101763]: Updates copy of libffi bundled with Windows installs to 3.4.4.

• gh-101759 [https://github.com/python/cpython/issues/101759]: Update Windows installer to SQLite 3.40.1.

• gh-101614 [https://github.com/python/cpython/issues/101614]: Correctly handle extensions built against debug binaries that reference python3_d.dll.

• gh-101196 [https://github.com/python/cpython/issues/101196]: The functions os.path.isdir, os.path.isfile, os.path.islink and os.path.exists are now 13% to 28% faster on Windows, by making fewer Win32 API calls.

macOS

• gh-101759 [https://github.com/python/cpython/issues/101759]: Update macOS installer to SQLite 3.40.1.

C API

• gh-101907 [https://github.com/python/cpython/issues/101907]: Removes use of non-standard C++ extension in public header files.

• gh-99293 [https://github.com/python/cpython/issues/99293]: Document that the Py_TPFLAGS_VALID_VERSION_TAG is an internal feature, should not be used, and will be removed.

• gh-101578 [https://github.com/python/cpython/issues/101578]: Add PyErr_GetRaisedException() and PyErr_SetRaisedException() for saving and restoring the current exception. These functions return and accept a single exception object, rather than the triple arguments of the now-deprecated PyErr_Fetch() and PyErr_Restore(). This is less error prone and a bit more efficient.

Add PyException_GetArgs() and PyException_SetArgs() as convenience functions for retrieving and modifying the args passed to the exception's constructor.

• gh-91744 [https://github.com/python/cpython/issues/91744]: Introduced the Unstable C API tier, marking APi that is allowed to change in minor releases without a deprecation period. See PEP 689 [https://peps.python.org/pep-0689/] for details.

Python 3.12.0 alpha 5

Release date: 2023-02-07

安全性

• gh-99108 [https://github.com/python/cpython/issues/99108]: Replace the builtin hashlib implementations of SHA2-224 and SHA2-256 originally from LibTomCrypt with formally verified, side-channel resistant code from the HACL* [https://github.com/hacl-star/hacl-star/] project. The builtins remain a fallback only used when OpenSSL does not provide them.

核心与内置函数

• gh-92173 [https://github.com/python/cpython/issues/92173]: Fix the defs and kwdefs arguments to PyEval_EvalCodeEx() and a reference leak in that function.

• gh-59956 [https://github.com/python/cpython/issues/59956]: The GILState API is now partially compatible with subinterpreters. Previously, PyThreadState_GET() and PyGILState_GetThisThreadState() would get out of sync, causing inconsistent behavior and crashes.

• gh-101400 [https://github.com/python/cpython/issues/101400]: Fix wrong lineno in exception message on continue or break which are not in a loop. Patch by Donghee Na.

• gh-101372 [https://github.com/python/cpython/issues/101372]: Fix is_normalized() to properly handle the UCD 3.2.0 cases. Patch by Donghee Na.

• gh-101266 [https://github.com/python/cpython/issues/101266]: Fix sys.getsizeof() reporting for int subclasses.

• gh-101291 [https://github.com/python/cpython/issues/101291]: Refactor the PyLongObject struct into a normal Python object header and a PyLongValue struct.

• gh-101046 [https://github.com/python/cpython/issues/101046]: Fix a possible memory leak in the parser when raising MemoryError. Patch by Pablo Galindo

• gh-101037 [https://github.com/python/cpython/issues/101037]: Fix potential memory underallocation issue for instances of int subclasses with value zero.

• gh-100762 [https://github.com/python/cpython/issues/100762]: Record the (virtual) exception block depth in the oparg of YIELD_VALUE. Use this to avoid the expensive throw() when closing generators (and coroutines) that can be closed trivially.

• gh-100982 [https://github.com/python/cpython/issues/100982]: Adds a new COMPARE_AND_BRANCH instruction. This is a bit more efficient when performing a comparison immediately followed by a branch, and restores the design intent of PEP 659 that specializations are local to a single instruction.

• gh-100942 [https://github.com/python/cpython/issues/100942]: Fixed segfault in property.getter/setter/deleter that occurred when a property subclass overrode the _new_ method to return a non-property instance.

• gh-100923 [https://github.com/python/cpython/issues/100923]: Remove the mask cache entry for the COMPARE_OP instruction and embed the mask into the oparg.

• gh-100892 [https://github.com/python/cpython/issues/100892]: Fix race while iterating over thread states in clearing threading.local. Patch by Kumar Aditya.

• gh-91351 [https://github.com/python/cpython/issues/91351]: Fix a case where reentrant imports could corrupt the import deadlock detection code and cause a KeyError to be raised out of importlib/_bootstrap. In addition to the straightforward cases, this could also happen when garbage collection leads to a warning being emitted — as happens when it collects an open socket or file)

• gh-100726 [https://github.com/python/cpython/issues/100726]: Optimize construction of range object for medium size integers.

• gh-100712 [https://github.com/python/cpython/issues/100712]: Added option to build cpython with specialization disabled, by setting ENABLE_SPECIALIZATION=False in opcode, followed by make regen-all.

• bpo-32780 [https://bugs.python.org/issue?@action=redirect&bpo=32780]: Inter-field padding is now inserted into the PEP3118 format strings obtained from ctypes.Structure objects, reflecting their true representation in memory.

库

• gh-101541 [https://github.com/python/cpython/issues/101541]: [Enum] - fix psuedo-flag creation

• gh-101570 [https://github.com/python/cpython/issues/101570]: Upgrade pip wheel bundled with ensurepip (pip 23.0)

• gh-101323 [https://github.com/python/cpython/issues/101323]: Fix a bug where errors where not thrown by zlib._ZlibDecompressor if encountered during decompressing.

• gh-101317 [https://github.com/python/cpython/issues/101317]: Add ssl_shutdown_timeout parameter for asyncio.StreamWriter.start_tls().

• gh-101326 [https://github.com/python/cpython/issues/101326]: Fix regression when passing None as second or third argument to FutureIter.throw.

• gh-92123 [https://github.com/python/cpython/issues/92123]: Adapt the _elementtree extension module to multiphase init ( PEP 489 [https://peps.python.org/pep-0489/]). Patches by Erlend E. Aasland.

• gh-100795 [https://github.com/python/cpython/issues/100795]: Avoid potential unexpected freeaddrinfo call (double free) in socket when when a libc getaddrinfo() implementation leaves garbage in an output pointer when returning an error. Original patch by Sergey G. Brester.

• gh-101143 [https://github.com/python/cpython/issues/101143]: Remove unused references to TimerHandle in asyncio.base_events.BaseEventLoop._add_callback.

• gh-101144 [https://github.com/python/cpython/issues/101144]: Make zipfile.Path.open() and zipfile.Path.read_text() also accept encoding as a positional argument. This was the behavior in Python 3.9 and earlier. 3.10 introduced a regression where supplying it as a positional argument would lead to a TypeError.

• gh-94518 [https://github.com/python/cpython/issues/94518]: Group-related variables of _posixsubprocess module are renamed to stress that supplementary group affinity is added to a fork, not replace the inherited ones. Patch by Oleg Iarygin.

• gh-101015 [https://github.com/python/cpython/issues/101015]: Fix typing.get_type_hints() on '*tuple[…]' and *tuple[…]. It must not drop the Unpack part.

• gh-101000 [https://github.com/python/cpython/issues/101000]: Add os.path.splitroot(), which splits a path into a 3-item tuple (drive, root, tail). This new function is used by pathlib to improve the performance of path construction by up to a third.

• gh-100573 [https://github.com/python/cpython/issues/100573]: Fix a Windows asyncio bug with named pipes where a client doing os.stat() on the pipe would cause an error in the server that disabled serving future requests.

• gh-39615 [https://github.com/python/cpython/issues/39615]: warnings.warn() now has the ability to skip stack frames based on code filename prefix rather than only a numeric stacklevel via the new skip_file_prefixes keyword argument.

• gh-100750 [https://github.com/python/cpython/issues/100750]: pass encoding kwarg to subprocess in platform

• gh-100160 [https://github.com/python/cpython/issues/100160]: Emit a deprecation warning in asyncio.DefaultEventLoopPolicy.get_event_loop() if there is no current event loop set and it decides to create one.

• gh-96290 [https://github.com/python/cpython/issues/96290]: Fix handling of partial and invalid UNC drives in ntpath.splitdrive(), and in ntpath.normpath() on non-Windows systems. Paths such as '\server' and '\' are now considered by splitdrive() to contain only a drive, and consequently are not modified by normpath() on non-Windows systems. The behaviour of normpath() on Windows systems is unaffected, as native OS APIs are used. Patch by Eryk Sun, with contributions by Barney Gale.

• gh-99952 [https://github.com/python/cpython/issues/99952]: Fix a reference undercounting issue in ctypes.Structure with from_param() results larger than a C pointer.

• gh-67790 [https://github.com/python/cpython/issues/67790]: Add float-style formatting support for fractions.Fraction instances.

• gh-99266 [https://github.com/python/cpython/issues/99266]: Preserve more detailed error messages in ctypes.

• gh-86682 [https://github.com/python/cpython/issues/86682]: Ensure runtime-created collections have the correct module name using the newly added (internal) sys._getframemodulename().

• gh-88597 [https://github.com/python/cpython/issues/88597]: uuid now has a command line interface. Try python -m uuid -h.

• gh-60580 [https://github.com/python/cpython/issues/60580]: ctypes.wintypes.BYTE definition changed from c_byte to c_ubyte to match Windows SDK. Patch by Anatoly Techtonik and Oleg Iarygin.

• gh-94518 [https://github.com/python/cpython/issues/94518]: _posixsubprocess now initializes all UID and GID variables using a reserved -1 value instead of a separate flag. Patch by Oleg Iarygin.

• bpo-38941 [https://bugs.python.org/issue?@action=redirect&bpo=38941]: The xml.etree.ElementTree module now emits DeprecationWarning when testing the truth value of an xml.etree.ElementTree.Element. Before, the Python implementation emitted FutureWarning, and the C implementation emitted nothing.

• bpo-40077 [https://bugs.python.org/issue?@action=redirect&bpo=40077]: Convert elementtree types to heap types. Patch by Erlend E. Aasland.

• bpo-29847 [https://bugs.python.org/issue?@action=redirect&bpo=29847]: Fix a bug where pathlib.Path accepted and ignored keyword arguments. Patch provided by Yurii Karabas.

• gh-77772 [https://github.com/python/cpython/issues/77772]: ctypes.CDLL, ctypes.OleDLL, ctypes.WinDLL, and ctypes.PyDLL now accept pathlike objects as their name argument. Patch by Robert Hoelzl.

文档

• gh-88324 [https://github.com/python/cpython/issues/88324]: Reword subprocess to emphasize default behavior of stdin, stdout, and stderr arguments. Remove inaccurate statement about child file handle inheritance.

测试

• gh-101334 [https://github.com/python/cpython/issues/101334]: test_tarfile has been updated to pass when run as a high UID.

构建

• gh-101282 [https://github.com/python/cpython/issues/101282]: Update BOLT configuration not to use deprecated usage of --split functions. Patch by Donghee Na.

• gh-101522 [https://github.com/python/cpython/issues/101522]: Allow overriding Windows dependencies versions and paths using MSBuild properties.

• gh-77532 [https://github.com/python/cpython/issues/77532]: Minor fixes to allow building with PlatformToolset=ClangCL on Windows.

• gh-101152 [https://github.com/python/cpython/issues/101152]: In accordance with PEP 699 [https://peps.python.org/pep-0699/], the ma_version_tag field in PyDictObject is deprecated for extension modules. Accessing this field will generate a compiler warning at compile time. This field will be removed in Python 3.14.

• gh-100340 [https://github.com/python/cpython/issues/100340]: Allows -Wno-int-conversion for wasm-sdk 17 and onwards, thus enables building WASI builds once against the latest sdk.

• gh-101060 [https://github.com/python/cpython/issues/101060]: Conditionally add -fno-reorder-blocks-and-partition in configure. Effectively fixes --enable-bolt when using Clang, as this appears to be a GCC-only flag.

• gh-98705 [https://github.com/python/cpython/issues/98705]: __bool__ is defined in AIX system header files which breaks the build in AIX, so undefine it.

• gh-98636 [https://github.com/python/cpython/issues/98636]: Fix a regression in detecting gdbm_compat library for the _gdbm module build.

• gh-96305 [https://github.com/python/cpython/issues/96305]: aixsupport now uses a simple code to get platform details rather than the now nonexistent _bootsubprocess during bootstrap.

Windows

• gh-101543 [https://github.com/python/cpython/issues/101543]: Ensure the install path in the registry is only used when the standard library hasn't been located in any other way.

• gh-101467 [https://github.com/python/cpython/issues/101467]: The py.exe launcher now correctly filters when only a single runtime is installed. It also correctly handles prefix matches on tags so that -3.1 does not match 3.11, but would still match 3.1-32.

• gh-99834 [https://github.com/python/cpython/issues/99834]: Updates bundled copy of Tcl/Tk to 8.6.13.0

• gh-101135 [https://github.com/python/cpython/issues/101135]: Restore ability to launch older 32-bit versions from the py.exe launcher when both 32-bit and 64-bit installs of the same version are available.

• gh-82052 [https://github.com/python/cpython/issues/82052]: Fixed an issue where writing more than 32K of Unicode output to the console screen in one go can result in mojibake.

• gh-100320 [https://github.com/python/cpython/issues/100320]: Ensures the PythonPath registry key from an install is used when launching from a different copy of Python that relies on an existing install to provide a copy of its modules and standard library.

• gh-100247 [https://github.com/python/cpython/issues/100247]: Restores support for the py.exe launcher finding shebang commands in its configuration file using the full command name.

Python 3.12.0 alpha 4

Release date: 2023-01-10

核心与内置函数

• gh-100776 [https://github.com/python/cpython/issues/100776]: Fix misleading default value in input()'s __textsignature_.

• gh-99005 [https://github.com/python/cpython/issues/99005]: Remove UNARY_POSITIVE, ASYNC_GEN_WRAP and LIST_TO_TUPLE, replacing them with intrinsics.

• gh-99005 [https://github.com/python/cpython/issues/99005]: Add new CALL_INTRINSIC_1 instruction. Remove IMPORT_STAR, PRINT_EXPR and STOPITERATION_ERROR, replacing them with the CALL_INTRINSIC_1 instruction.

• gh-100288 [https://github.com/python/cpython/issues/100288]: Remove the LOAD_ATTR_METHOD_WITH_DICT specialized instruction. Stats show it is not useful.

• gh-100720 [https://github.com/python/cpython/issues/100720]: Added PyFrameNumSlotsForCodeObject, which returns the number of slots needed in a frame for a given code object.

• gh-100719 [https://github.com/python/cpython/issues/100719]: Removed the co_nplaincellvars field from the code object, as it is redundant.

• gh-100637 [https://github.com/python/cpython/issues/100637]: Fix int.__sizeof__() calculation to include the 1-element ob_digit array for 0 and False.

• gh-100649 [https://github.com/python/cpython/issues/100649]: Update the native_thread_id field of PyThreadState after fork.

• gh-100126 [https://github.com/python/cpython/issues/100126]: Fix an issue where "incomplete" frames could be briefly visible to C code while other frames are being torn down, possibly resulting in corruption or hard crashes of the interpreter while running finalizers.

• gh-87447 [https://github.com/python/cpython/issues/87447]: Fix SyntaxError on comprehension rebind checking with names that are not actually redefined.

Now reassigning b in [(b := 1) for a, b.prop in some_iter] is allowed. Reassigning a is still disallowed as per PEP 572 [https://peps.python.org/pep-0572/].

• gh-100268 [https://github.com/python/cpython/issues/100268]: Add int.is_integer() to improve duck type compatibility between int and float.

• gh-100425 [https://github.com/python/cpython/issues/100425]: Improve the accuracy of sum() with compensated summation.

• gh-100374 [https://github.com/python/cpython/issues/100374]: Fix incorrect result and delay in socket.getfqdn(). Patch by Dominic Socular.

• gh-100357 [https://github.com/python/cpython/issues/100357]: Convert vars, dir, next, getattr, and iter to argument clinic.

• gh-100117 [https://github.com/python/cpython/issues/100117]: Improve the output of codeobject.co_lines() by emitting only one entry for each line range.

• gh-90043 [https://github.com/python/cpython/issues/90043]: Handle NaNs when specializing COMPARE_OP for float values.

• gh-100222 [https://github.com/python/cpython/issues/100222]: Redefine the PyCODEUNIT typedef as a union to describe its layout to the C compiler, avoiding type punning and improving clarity.

• gh-99955 [https://github.com/python/cpython/issues/99955]: Internal compiler functions (in compile.c) now consistently return -1 on error and 0 on success.

• gh-100188 [https://github.com/python/cpython/issues/100188]: The BINARY_SUBSCR_LIST_INT and BINARY_SUBSCR_TUPLE_INT instructions are no longer used for negative integers because those instructions always miss when encountering negative integers.

• gh-99110 [https://github.com/python/cpython/issues/99110]: Initialize frame->previous in frameobject.c to fix a segmentation fault when accessing frames created by PyFrame_New().

• gh-94155 [https://github.com/python/cpython/issues/94155]: Improved the hashing algorithm for code objects, mitigating some hash collisions.

• gh-99540 [https://github.com/python/cpython/issues/99540]: None now hashes to a constant value. This is not a requirements change.

• gh-100143 [https://github.com/python/cpython/issues/100143]: When built with --enable-pystats, stats collection is now off by default. To enable it early at startup, pass the -Xpystats flag. Stats are now always dumped, even if switched off.

• gh-100146 [https://github.com/python/cpython/issues/100146]: Improve BUILD_LIST opcode so that it works similarly to the BUILD_TUPLE opcode, by stealing references from the stack rather than repeatedly using stack operations to set list elements. Implementation details are in a new private API PyListFromArraySteal().

• gh-100110 [https://github.com/python/cpython/issues/100110]: Specialize FOR_ITER for tuples.

• gh-100050 [https://github.com/python/cpython/issues/100050]: Honor existing errors obtained when searching for mismatching parentheses in the tokenizer. Patch by Pablo Galindo

• gh-92216 [https://github.com/python/cpython/issues/92216]: Improve the performance of hasattr() for type objects with a missing attribute.

• gh-99582 [https://github.com/python/cpython/issues/99582]: Freeze zipimport module into bootstrappython.

• gh-99554 [https://github.com/python/cpython/issues/99554]: Pack debugging location tables more efficiently during bytecode compilation.

• gh-98522 [https://github.com/python/cpython/issues/98522]: Add an internal version number to code objects, to give better versioning of inner functions and comprehensions, and thus better specialization of those functions. This change is invisible to both Python and C extensions.

• gh-94603 [https://github.com/python/cpython/issues/94603]: Improve performance of list.pop for small lists.

• gh-89051 [https://github.com/python/cpython/issues/89051]: Add ssl.OP_LEGACY_SERVER_CONNECT

• bpo-32782 [https://bugs.python.org/issue?@action=redirect&bpo=32782]: ctypes arrays of length 0 now report a correct itemsize when a memoryview is constructed from them, rather than always giving a value of 0.

库

• gh-100833 [https://github.com/python/cpython/issues/100833]: Speed up math.fsum() by removing defensive volatile qualifiers.

• gh-100805 [https://github.com/python/cpython/issues/100805]: Modify random.choice() implementation to once again work with NumPy arrays.

• gh-100813 [https://github.com/python/cpython/issues/100813]: Add socket.IP_PKTINFO constant.

• gh-100792 [https://github.com/python/cpython/issues/100792]: Make email.message.Message.__contains__() twice as fast.

• gh-91851 [https://github.com/python/cpython/issues/91851]: Microoptimizations for fractions.Fraction.__round__(), fractions.Fraction.__ceil__() and fractions.Fraction.__floor__().

• gh-90104 [https://github.com/python/cpython/issues/90104]: Avoid RecursionError on repr if a dataclass field definition has a cyclic reference.

• gh-100689 [https://github.com/python/cpython/issues/100689]: Fix crash in pyexpat by statically allocating PyExpat_CAPI capsule.

• gh-100740 [https://github.com/python/cpython/issues/100740]: Fix unittest.mock.Mock not respecting the spec for attribute names prefixed with assert.

• gh-91219 [https://github.com/python/cpython/issues/91219]: Change SimpleHTTPRequestHandler to support subclassing to provide a different set of index file names instead of using __init__ parameters.

• gh-100690 [https://github.com/python/cpython/issues/100690]: Mock objects which are not unsafe will now raise an AttributeError when accessing an attribute that matches the name of an assertion but without the prefix assert_, e.g. accessing called_once instead of assert_called_once. This is in addition to this already happening for accessing attributes with prefixes assert, assret, asert, aseert, and assrt.

• gh-89727 [https://github.com/python/cpython/issues/89727]: Simplify and optimize os.walk() by using isinstance() checks to check the top of the stack.

• gh-100485 [https://github.com/python/cpython/issues/100485]: Add math.sumprod() to compute the sum of products.

• gh-86508 [https://github.com/python/cpython/issues/86508]: Fix asyncio.open_connection() to skip binding to local addresses of different family. Patch by Kumar Aditya.

• gh-97930 [https://github.com/python/cpython/issues/97930]: importlib.resources.files now accepts a module as an anchor instead of only accepting packages. If a module is passed, resources are resolved adjacent to that module (in the same package or at the package root). The parameter was renamed from package to anchor with a compatibility shim for those passing by keyword. Additionally, the new anchor parameter is now optional and will default to the caller's module.

• gh-100585 [https://github.com/python/cpython/issues/100585]: Fixed a bug where importlib.resources.as_file was leaving file pointers open

• gh-100562 [https://github.com/python/cpython/issues/100562]: Improve performance of pathlib.Path.absolute() by nearly 2x. This comes at the cost of a performance regression in pathlib.Path.cwd(), which is generally used less frequently in user code.

• gh-100519 [https://github.com/python/cpython/issues/100519]: Small simplification of http.cookiejar.eff_request_host() that improves readability and better matches the RFC wording.

• gh-100287 [https://github.com/python/cpython/issues/100287]: Fix the interaction of unittest.mock.seal() with unittest.mock.AsyncMock.

• gh-100488 [https://github.com/python/cpython/issues/100488]: Add Fraction.is_integer() to check whether a fractions.Fraction is an integer. This improves duck type compatibility with float and int.

• gh-100474 [https://github.com/python/cpython/issues/100474]: http.server now checks that an index page is actually a regular file before trying to serve it. This avoids issues with directories named index.html.

• gh-100363 [https://github.com/python/cpython/issues/100363]: Speed up asyncio.get_running_loop() by removing redundant getpid checks. Patch by Kumar Aditya.

• gh-78878 [https://github.com/python/cpython/issues/78878]: Fix crash when creating an instance of _ctypes.CField.

• gh-100348 [https://github.com/python/cpython/issues/100348]: Fix ref cycle in asyncio._SelectorSocketTransport by removing readready_cb in close.

• gh-100344 [https://github.com/python/cpython/issues/100344]: Provide C implementation for asyncio.current_task() for a 4x-6x speedup.

• gh-100272 [https://github.com/python/cpython/issues/100272]: Fix JSON serialization of OrderedDict. It now preserves the order of keys.

• gh-83076 [https://github.com/python/cpython/issues/83076]: Instantiation of Mock() and AsyncMock() is now 3.8x faster.

• gh-100234 [https://github.com/python/cpython/issues/100234]: Set a default value of 1.0 for the lambd parameter in random.expovariate().

• gh-100228 [https://github.com/python/cpython/issues/100228]: A DeprecationWarning may be raised when os.fork() or os.forkpty() is called from multithreaded processes. Forking with threads is unsafe and can cause deadlocks, crashes and subtle problems. Lack of a warning does not indicate that the fork call was actually safe, as Python may not be aware of all threads.

• gh-100039 [https://github.com/python/cpython/issues/100039]: Improve signatures for enums and flags.

• gh-100133 [https://github.com/python/cpython/issues/100133]: Fix regression in asyncio where a subprocess would sometimes lose data received from pipe.

• bpo-44592 [https://bugs.python.org/issue?@action=redirect&bpo=44592]: Fixes inconsistent handling of case sensitivity of extrasaction arg in csv.DictWriter.

• gh-100098 [https://github.com/python/cpython/issues/100098]: Fix tuple subclasses being cast to tuple when used as enum values.

• gh-85432 [https://github.com/python/cpython/issues/85432]: Rename the fmt parameter of the pure-Python implementation of datetime.time.strftime() to format. Rename the t parameter of datetime.datetime.fromtimestamp() to timestamp. These changes mean the parameter names in the pure-Python implementation now match the parameter names in the C implementation. Patch by Alex Waygood.

• gh-98778 [https://github.com/python/cpython/issues/98778]: Update HTTPError to be initialized properly, even if the fp is None. Patch by Donghee Na.

• gh-99925 [https://github.com/python/cpython/issues/99925]: Unify error messages in JSON serialization between json.dumps(float('nan'), allow_nan=False) and json.dumps(float('nan'), allow_nan=False, indent=). Now both include the representation of the value that could not be serialized.

• gh-89727 [https://github.com/python/cpython/issues/89727]: Fix issue with os.walk() where a RecursionError would occur on deep directory structures by adjusting the implementation of os.walk() to be iterative instead of recursive.

• gh-94943 [https://github.com/python/cpython/issues/94943]: Add 数据类支持 to the Enum _repr_(). When inheriting from a dataclass, only show the field names in the value section of the member repr(), and not the dataclass' class name.

• gh-83035 [https://github.com/python/cpython/issues/83035]: Fix inspect.getsource() handling of decorator calls with nested parentheses.

• gh-99576 [https://github.com/python/cpython/issues/99576]: Fix .save() method for LWPCookieJar and MozillaCookieJar: saved file was not truncated on repeated save.

• gh-94912 [https://github.com/python/cpython/issues/94912]: Add inspect.markcoroutinefunction() decorator which manually marks a function as a coroutine for the benefit of iscoroutinefunction().

• gh-99509 [https://github.com/python/cpython/issues/99509]: Add PEP 585 [https://peps.python.org/pep-0585/] support for multiprocessing.queues.Queue.

• gh-99482 [https://github.com/python/cpython/issues/99482]: Remove Jython partial compatibility code from several stdlib modules.

• gh-99433 [https://github.com/python/cpython/issues/99433]: Fix doctest failure on types.MethodWrapperType in modules.

• gh-85267 [https://github.com/python/cpython/issues/85267]: Several improvements to inspect.signature()'s handling of __text_signature. - Fixes a case where inspect.signature() dropped parameters - Fixes a case where inspect.signature() raised tokenize.TokenError - Allows inspect.signature() to understand defaults involving binary operations of constants - inspect.signature() is documented as only raising TypeError or ValueError, but sometimes raised RuntimeError. These cases now raise ValueError - Removed a dead code path

• gh-91166 [https://github.com/python/cpython/issues/91166]: asyncio is optimized to avoid excessive copying when writing to socket and use sendmsg() if the platform supports it. Patch by Kumar Aditya.

• gh-98030 [https://github.com/python/cpython/issues/98030]: Add missing TCP socket options from Linux: TCP_MD5SIG, TCP_THIN_LINEAR_TIMEOUTS, TCP_THIN_DUPACK, TCP_REPAIR, TCP_REPAIR_QUEUE, TCP_QUEUE_SEQ, TCP_REPAIR_OPTIONS, TCP_TIMESTAMP, TCP_CC_INFO, TCP_SAVE_SYN, TCP_SAVED_SYN, TCP_REPAIR_WINDOW, TCP_FASTOPEN_CONNECT, TCP_ULP, TCP_MD5SIG_EXT, TCP_FASTOPEN_KEY, TCP_FASTOPEN_NO_COOKIE, TCP_ZEROCOPY_RECEIVE, TCP_INQ, TCP_TX_DELAY.

• gh-88500 [https://github.com/python/cpython/issues/88500]: Reduced the memory usage of urllib.parse.unquote() and urllib.parse.unquote_to_bytes() on large values.

• gh-96127 [https://github.com/python/cpython/issues/96127]: inspect.signature was raising TypeError on call with mock objects. Now it correctly returns (*args, **kwargs) as inferred signature.

• gh-95882 [https://github.com/python/cpython/issues/95882]: Fix a 3.11 regression in asynccontextmanager(), which caused it to propagate exceptions with incorrect tracebacks and fix a 3.11 regression in contextmanager(), which caused it to propagate exceptions with incorrect tracebacks for StopIteration.

• gh-78707 [https://github.com/python/cpython/issues/78707]: Deprecate passing more than one positional argument to pathlib.PurePath.relative_to() and is_relative_to().

• gh-92122 [https://github.com/python/cpython/issues/92122]: Fix reStructuredText syntax errors in docstrings in the enum module.

• gh-91851 [https://github.com/python/cpython/issues/91851]: Optimize the Fraction arithmetics for small components.

• bpo-24132 [https://bugs.python.org/issue?@action=redirect&bpo=24132]: Make pathlib.PurePath and Path subclassable (private to start). Previously, attempting to instantiate a subclass resulted in an AttributeError being raised. Patch by Barney Gale.

• bpo-40447 [https://bugs.python.org/issue?@action=redirect&bpo=40447]: Accept os.PathLike (such as pathlib.Path) in the stripdir arguments of compileall.compile_file() and compileall.compile_dir().

• bpo-36880 [https://bugs.python.org/issue?@action=redirect&bpo=36880]: Fix a reference counting issue when a ctypes callback with return type py_object returns None, which could cause crashes.