3.15.0a2 - Cpython — ContextQMD

.. date: 2025-11-04-19-20-05 .. gh-issue: 140849 .. nonce: YjB2ZZ .. release date: 2025-11-18 .. section: Windows

Update bundled liblzma to version 5.8.1.

.. date: 2025-11-12-12-54-28 .. gh-issue: 141442 .. nonce: 50dS3P .. section: Tools/Demos

The iOS testbed now correctly handles test arguments that contain spaces.

.. date: 2025-10-29-15-20-19 .. gh-issue: 140702 .. nonce: ZXtW8h .. section: Tools/Demos

The iOS testbed app will now expose the GITHUB_ACTIONS environment variable to iOS apps being tested.

.. date: 2025-09-21-10-30-08 .. gh-issue: 139198 .. nonce: Fm7NfU .. section: Tools/Demos

Remove Tools/scripts/checkpip.py script.

.. date: 2025-09-20-20-31-54 .. gh-issue: 139188 .. nonce: zfcxkW .. section: Tools/Demos

Remove Tools/tz/zdump.py script.

.. date: 2025-10-23-16-39-49 .. gh-issue: 140482 .. nonce: ZMtyeD .. section: Tests

Preserve and restore the state of stty echo as part of the test environment.

.. date: 2025-10-15-00-52-12 .. gh-issue: 140082 .. nonce: fpET50 .. section: Tests

Update python -m test to set FORCE_COLOR=1 when being run with color enabled so that :mod:unittest which is run by it with redirected output will output in color.

.. date: 2025-07-09-21-45-51 .. gh-issue: 136442 .. nonce: jlbklP .. section: Tests

Use exitcode 1 instead of 5 if :func:unittest.TestCase.setUpClass raises an exception

.. date: 2025-08-15-23-08-44 .. gh-issue: 137836 .. nonce: b55rhh .. section: Security

Add support of the "plaintext" element, RAWTEXT elements "xmp", "iframe", "noembed" and "noframes", and optionally RAWTEXT element "noscript" in :class:html.parser.HTMLParser.

.. date: 2025-06-28-13-23-53 .. gh-issue: 136063 .. nonce: aGk0Jv .. section: Security

:mod:email.message: ensure linear complexity for legacy HTTP parameters parsing. Patch by Bénédikt Tran.

.. date: 2025-05-30-22-33-27 .. gh-issue: 136065 .. nonce: bu337o .. section: Security

Fix quadratic complexity in :func:os.path.expandvars.

.. date: 2025-11-14-16-24-20 .. gh-issue: 141497 .. nonce: L_CxDJ .. section: Library

:mod:ipaddress: ensure that the methods :meth:IPv4Network.hosts() <ipaddress.IPv4Network.hosts> and :meth:IPv6Network.hosts() <ipaddress.IPv6Network.hosts> always return an iterator.

.. date: 2025-11-13-14-51-30 .. gh-issue: 140938 .. nonce: kXsHHv .. section: Library

The :func:statistics.stdev and :func:statistics.pstdev functions now raise a :exc:ValueError when the input contains an infinity or a NaN.

.. date: 2025-11-12-15-42-47 .. gh-issue: 124111 .. nonce: hTw4OE .. section: Library

Updated Tcl threading configuration in :mod:_tkinter to assume that threads are always available in Tcl 9 and later.

.. date: 2025-11-12-01-49-03 .. gh-issue: 137109 .. nonce: D6sq2B .. section: Library

The :mod:os.fork and related forking APIs will no longer warn in the common case where Linux or macOS platform APIs return the number of threads in a process and find the answer to be 1 even when a :func:os.register_at_fork after_in_parent= callback (re)starts a thread.

.. date: 2025-11-10-01-47-18 .. gh-issue: 141314 .. nonce: baaa28 .. section: Library

Fix assertion failure in :meth:io.TextIOWrapper.tell when reading files with standalone carriage return (\r) line endings.

.. date: 2025-11-09-18-55-13 .. gh-issue: 141311 .. nonce: qZ3swc .. section: Library

Fix assertion failure in :func:!io.BytesIO.readinto and undefined behavior arising when read position is above capcity in :class:io.BytesIO.

.. date: 2025-11-08-13-03-10 .. gh-issue: 87710 .. nonce: XJeZlP .. section: Library

:mod:mimetypes: Update mime type for .ai files to application/pdf.

.. date: 2025-11-07-12-25-46 .. gh-issue: 85524 .. nonce: 9SWFIC .. section: Library

Update io.FileIO.readall, an implementation of :meth:io.RawIOBase.readall, to follow :class:io.IOBase guidelines and raise :exc:io.UnsupportedOperation when a file is in "w" mode rather than :exc:OSError

.. date: 2025-11-06-15-11-50 .. gh-issue: 141141 .. nonce: tgIfgH .. section: Library

Fix a thread safety issue with :func:base64.b85decode. Contributed by Benel Tayar.

.. date: 2025-11-04-20-08-41 .. gh-issue: 141018 .. nonce: d_oyOI .. section: Library

:mod:mimetypes: Update .exe, .dll, .rtf and (when strict=False) .jpg to their correct IANA mime type.

.. date: 2025-11-04-15-40-35 .. gh-issue: 137969 .. nonce: 9VZQVt .. section: Library

Fix :meth:annotationlib.ForwardRef.evaluate returning :class:~annotationlib.ForwardRef objects which don't update with new globals.

.. date: 2025-11-04-12-16-13 .. gh-issue: 75593 .. nonce: EFVhKR .. section: Library

Add support of :term:path-like objects <path-like object> and :term:bytes-like objects <bytes-like object> in :func:wave.open.

.. date: 2025-11-03-16-23-54 .. gh-issue: 140797 .. nonce: DuFEeR .. section: Library

The undocumented :class:!re.Scanner class now forbids regular expressions containing capturing groups in its lexicon patterns. Patterns using capturing groups could previously lead to crashes with segmentation fault. Use non-capturing groups (?:...) instead.

.. date: 2025-11-03-05-38-31 .. gh-issue: 125115 .. nonce: jGS8MN .. section: Library

Refactor the :mod:pdb parsing issue so positional arguments can pass through intuitively.

.. date: 2025-11-02-19-23-32 .. gh-issue: 140815 .. nonce: McEG-T .. section: Library

:mod:faulthandler now detects if a frame or a code object is invalid or freed. Patch by Victor Stinner.

.. date: 2025-11-02-11-46-00 .. gh-issue: 100218 .. nonce: 9Ezfdq .. section: Library

Correctly set :attr:~OSError.errno when :func:socket.if_nametoindex or :func:socket.if_indextoname raise an :exc:OSError. Patch by Bénédikt Tran.

.. date: 2025-11-02-09-37-22 .. gh-issue: 140734 .. nonce: f8gST9 .. section: Library

:mod:multiprocessing: fix off-by-one error when checking the length of a temporary socket file path. Patch by Bénédikt Tran.

.. date: 2025-11-01-14-44-09 .. gh-issue: 140873 .. nonce: kfuc9B .. section: Library

Add support of non-:term:descriptor callables in :func:functools.singledispatchmethod.

.. date: 2025-11-01-00-36-14 .. gh-issue: 140874 .. nonce: eAWt3K .. section: Library

Bump the version of pip bundled in ensurepip to version 25.3

.. date: 2025-11-01-00-34-53 .. gh-issue: 140826 .. nonce: JEDd7U .. section: Library

Now :class:!winreg.HKEYType objects are compared by their underlying Windows registry handle value instead of their object identity.

.. date: 2025-10-31-16-25-13 .. gh-issue: 140808 .. nonce: XBiQ4j .. section: Library

The internal class mailbox._ProxyFile is no longer a parameterized generic.

.. date: 2025-10-31-15-06-26 .. gh-issue: 140691 .. nonce: JzHGtg .. section: Library

In :mod:urllib.request, when opening a FTP URL fails because a data connection cannot be made, the control connection's socket is now closed to avoid a :exc:ResourceWarning.

.. date: 2025-10-31-13-57-55 .. gh-issue: 103847 .. nonce: VM7TnW .. section: Library

Fix hang when cancelling process created by :func:asyncio.create_subprocess_exec or :func:asyncio.create_subprocess_shell. Patch by Kumar Aditya.

.. date: 2025-10-30-15-33-07 .. gh-issue: 137821 .. nonce: 8_Iavt .. section: Library

Convert _json module to use Argument Clinic. Patched by Yoonho Hann.

.. date: 2025-10-30-12-36-19 .. gh-issue: 140790 .. nonce: _3T6-N .. section: Library

Initialize all Pdb's instance variables in __init__, remove some hasattr/getattr

.. date: 2025-10-29-16-53-00 .. gh-issue: 140766 .. nonce: CNagKF .. section: Library

Add :func:enum.show_flag_values and enum.bin to enum.__all__.

.. date: 2025-10-29-16-12-41 .. gh-issue: 120057 .. nonce: qGj5Dl .. section: Library

Add :func:os.reload_environ to os.__all__.

.. date: 2025-10-29-09-40-10 .. gh-issue: 140741 .. nonce: L13UCV .. section: Library

Fix profiling.sampling.sample() incorrectly handling a :exc:FileNotFoundError or :exc:PermissionError.

.. date: 2025-10-28-17-43-51 .. gh-issue: 140228 .. nonce: 8kfHhO .. section: Library

Avoid making unnecessary filesystem calls for frozen modules in :mod:linecache when the global module cache is not present.

.. date: 2025-10-28-02-46-56 .. gh-issue: 139946 .. nonce: aN3_uY .. section: Library

Error and warning keywords in argparse.ArgumentParser messages are now colorized when color output is enabled, fixing a visual inconsistency in which they remained plain text while other output was colorized.

.. date: 2025-10-27-18-29-42 .. gh-issue: 140590 .. nonce: LT9HHn .. section: Library

Fix arguments checking for the :meth:!functools.partial.__setstate__ that may lead to internal state corruption and crash. Patch by Sergey Miryanov.

.. date: 2025-10-27-16-01-41 .. gh-issue: 125434 .. nonce: qy0uRA .. section: Library

Display thread name in :mod:faulthandler on Windows. Patch by Victor Stinner.

.. date: 2025-10-27-13-49-31 .. gh-issue: 140634 .. nonce: ULng9G .. section: Library

Fix a reference counting bug in :meth:!os.sched_param.__reduce__.

.. date: 2025-10-27-00-40-49 .. gh-issue: 140650 .. nonce: DYJPJ9 .. section: Library

Fix an issue where closing :class:io.BufferedWriter could crash if the closed attribute raised an exception on access or could not be converted to a boolean.

.. date: 2025-10-26-16-24-12 .. gh-issue: 140633 .. nonce: ioayC1 .. section: Library

Ignore :exc:AttributeError when setting a module's __file__ attribute when loading an extension module packaged as Apple Framework.

.. date: 2025-10-25-22-55-07 .. gh-issue: 140601 .. nonce: In3MlS .. section: Library

:func:xml.etree.ElementTree.iterparse now emits a :exc:ResourceWarning when the iterator is not explicitly closed and was opened with a filename. This helps developers identify and fix resource leaks. Patch by Osama Abdelkader.

.. date: 2025-10-25-21-26-16 .. gh-issue: 140593 .. nonce: OxlLc9 .. section: Library

:mod:xml.parsers.expat: Fix a memory leak that could affect users with :meth:~xml.parsers.expat.xmlparser.ElementDeclHandler set to a custom element declaration handler. Patch by Sebastian Pipping.

.. date: 2025-10-25-21-04-00 .. gh-issue: 140607 .. nonce: oOZGxS .. section: Library

Inside :meth:io.RawIOBase.read, validate that the count of bytes returned by :meth:io.RawIOBase.readinto is valid (inside the provided buffer).

.. date: 2025-10-23-19-39-16 .. gh-issue: 138162 .. nonce: Znw5DN .. section: Library

Fix :class:logging.LoggerAdapter with merge_extra=True and without the extra argument.

.. date: 2025-10-23-13-42-15 .. gh-issue: 140481 .. nonce: XKxWpq .. section: Library

Improve error message when trying to iterate a Tk widget, image or font.

.. date: 2025-10-23-12-12-22 .. gh-issue: 138774 .. nonce: mnh2gU .. section: Library

:func:ast.unparse now generates full source code when handling :class:ast.Interpolation nodes that do not have a specified source.

.. date: 2025-10-22-20-52-13 .. gh-issue: 140474 .. nonce: xIWlip .. section: Library

Fix memory leak in :class:array.array when creating arrays from an empty :class:str and the u type code.

.. date: 2025-10-22-12-56-57 .. gh-issue: 140448 .. nonce: GsEkXD .. section: Library

Change the default of suggest_on_error to True in argparse.ArgumentParser.

.. date: 2025-10-21-15-54-13 .. gh-issue: 137530 .. nonce: ZyIVUH .. section: Library

:mod:dataclasses Fix annotations for generated __init__ methods by replacing the annotations that were in-line in the generated source code with __annotate__ functions attached to the methods.

.. date: 2025-10-20-12-33-49 .. gh-issue: 140348 .. nonce: SAKnQZ .. section: Library

Fix regression in Python 3.14.0 where using the | operator on a :class:typing.Union object combined with an object that is not a type would raise an error.

.. date: 2025-10-18-15-20-25 .. gh-issue: 76007 .. nonce: SNUzRq .. section: Library

:mod:decimal: Deprecate __version__ and replace with :data:decimal.SPEC_VERSION.

.. date: 2025-10-18-14-30-21 .. gh-issue: 76007 .. nonce: peEgcr .. section: Library

Deprecate __version__ from :mod:imaplib. Patch by Hugo van Kemenade.

.. date: 2025-10-17-23-58-11 .. gh-issue: 140272 .. nonce: lhY8uS .. section: Library

Fix memory leak in the :meth:!clear method of the :mod:dbm.gnu database.

.. date: 2025-10-17-20-42-38 .. gh-issue: 129117 .. nonce: X9jr4p .. section: Library

:mod:unicodedata: Add :func:~unicodedata.isxidstart and :func:~unicodedata.isxidcontinue functions to check whether a character can start or continue a Unicode Standard Annex #31 <https://www.unicode.org/reports/tr31/>_ identifier.

.. date: 2025-10-17-12-33-01 .. gh-issue: 140251 .. nonce: esM-OX .. section: Library

Colorize the default import statement import asyncio in asyncio REPL.

.. date: 2025-10-16-22-49-16 .. gh-issue: 140212 .. nonce: llBNd0 .. section: Library

Calendar's HTML formatting now accepts year and month as options. Previously, running python -m calendar -t html 2025 10 would result in an error message. It now generates an HTML document displaying the calendar for the specified month. Contributed by Pål Grønås Drange.

.. date: 2025-10-16-17-17-20 .. gh-issue: 135801 .. nonce: faH3fa .. section: Library

Improve filtering by module in :func:warnings.warn_explicit if no module argument is passed. It now tests the module regular expression in the warnings filter not only against the filename with .py stripped, but also against module names constructed starting from different parent directories of the filename (with /__init__.py, .py and, on Windows, .pyw stripped).

.. date: 2025-10-16-16-10-11 .. gh-issue: 139707 .. nonce: zR6Qtn .. section: Library

Improve :exc:ModuleNotFoundError error message when a :term:standard library module is missing.

.. date: 2025-10-15-21-42-13 .. gh-issue: 140041 .. nonce: _Fka2j .. section: Library

Fix import of :mod:ctypes on Android and Cygwin when ABI flags are present.

.. date: 2025-10-15-20-47-04 .. gh-issue: 140120 .. nonce: 3gffZq .. section: Library

Fixed a memory leak in :mod:hmac when it was using the hacl-star backend. Discovered by @ashm-dev using AddressSanitizer.

.. date: 2025-10-15-17-23-51 .. gh-issue: 140141 .. nonce: j2mUDB .. section: Library

The :py:class:importlib.metadata.PackageNotFoundError traceback raised when importlib.metadata.Distribution.from_name cannot discover a distribution no longer includes a transient :exc:StopIteration exception trace.

Contributed by Bartosz Sławecki in :gh:140142.

.. date: 2025-10-15-15-10-34 .. gh-issue: 140166 .. nonce: NtxRez .. section: Library

:mod:mimetypes: Per the IANA assignment <https://www.iana.org/assignments/media-types/application/texinfo>_, update the MIME type for the .texi and .texinfo file formats to application/texinfo, instead of application/x-texinfo.

.. date: 2025-10-15-02-26-50 .. gh-issue: 140135 .. nonce: 54JYfM .. section: Library

Speed up :meth:io.RawIOBase.readall by using PyBytesWriter API (about 4x faster)

.. date: 2025-10-14-20-27-06 .. gh-issue: 76007 .. nonce: 2NcUbo .. section: Library

:mod:zlib: Deprecate __version__ and schedule for removal in Python 3.20.

.. date: 2025-10-13-11-25-41 .. gh-issue: 136702 .. nonce: uvLGK1 .. section: Library

:mod:encodings: Deprecate passing a non-ascii encoding name to :func:encodings.normalize_encoding and schedule removal of support for Python 3.17.

.. date: 2025-10-11-09-07-06 .. gh-issue: 139940 .. nonce: g54efZ .. section: Library

Print clearer error message when using pdb to attach to a non-existing process.

.. date: 2025-10-02-22-29-00 .. gh-issue: 139462 .. nonce: VZXUHe .. section: Library

When a child process in a :class:concurrent.futures.ProcessPoolExecutor terminates abruptly, the resulting traceback will now tell you the PID and exit code of the terminated process. Contributed by Jonathan Berg.

.. date: 2025-09-30-12-52-54 .. gh-issue: 63161 .. nonce: mECM1A .. section: Library

Fix :func:tokenize.detect_encoding. Support non-UTF-8 shebang and comments if non-UTF-8 encoding is specified. Detect decoding error for non-UTF-8 encoding. Detect null bytes in source code.

.. date: 2025-09-25-20-16-10 .. gh-issue: 101828 .. nonce: yTxJlJ .. section: Library

Fix 'shift_jisx0213', 'shift_jis_2004', 'euc_jisx0213' and 'euc_jis_2004' codecs truncating null chars as they were treated as part of multi-character sequences.

.. date: 2025-09-23-09-46-46 .. gh-issue: 139246 .. nonce: pzfM-w .. section: Library

fix: paste zero-width in default repl width is wrong.

.. date: 2025-09-18-21-25-41 .. gh-issue: 83714 .. nonce: TQjDWZ .. section: Library

Implement :func:os.statx on Linux kernel versions 4.11 and later with glibc versions 2.28 and later. Contributed by Jeffrey Bosboom and Victor Stinner.

.. date: 2025-09-15-21-03-11 .. gh-issue: 138891 .. nonce: oZFdtR .. section: Library

Fix SyntaxError when inspect.get_annotations(f, eval_str=True) is called on a function annotated with a :pep:646 star_expression

.. date: 2025-09-13-12-19-17 .. gh-issue: 138859 .. nonce: PxjIoN .. section: Library

Fix generic type parameterization raising a :exc:TypeError when omitting a :class:ParamSpec that has a default which is not a list of types.

.. date: 2025-09-12-09-34-37 .. gh-issue: 138764 .. nonce: mokHoY .. section: Library

Prevent :func:annotationlib.call_annotate_function from calling __annotate__ functions that don't support VALUE_WITH_FAKE_GLOBALS in a fake globals namespace with empty globals.

Make FORWARDREF and STRING annotations fall back to using VALUE annotations in the case that neither their own format, nor VALUE_WITH_FAKE_GLOBALS are supported.

.. date: 2025-09-11-15-03-37 .. gh-issue: 138775 .. nonce: w7rnSx .. section: Library

Use of python -m with :mod:base64 has been fixed to detect input from a terminal so that it properly notices EOF.

.. date: 2025-09-03-20-18-39 .. gh-issue: 98896 .. nonce: tjez89 .. section: Library

Fix a failure in multiprocessing resource_tracker when SharedMemory names contain colons. Patch by Rani Pinchuk.

.. date: 2025-09-03-18-26-07 .. gh-issue: 138425 .. nonce: cVE9Ho .. section: Library

Fix partial evaluation of :class:annotationlib.ForwardRef objects which rely on names defined as globals.

.. date: 2025-08-26-08-17-56 .. gh-issue: 138151 .. nonce: I6CdAk .. section: Library

In :mod:annotationlib, improve evaluation of forward references to nonlocal variables that are not yet defined when the annotations are initially evaluated.

.. date: 2025-08-15-20-35-30 .. gh-issue: 69528 .. nonce: qc-Eh_ .. section: Library

The :attr:~io.FileIO.mode attribute of files opened in the 'wb+' mode is now 'wb+' instead of 'rb+'.

.. date: 2025-08-11-04-52-18 .. gh-issue: 137627 .. nonce: Ku5Yi2 .. section: Library

Speed up :meth:csv.Sniffer.sniff delimiter detection by up to 1.6x.

.. date: 2025-07-14-09-33-17 .. gh-issue: 55531 .. nonce: Gt2e12 .. section: Library

:mod:encodings: Improve :func:~encodings.normalize_encoding performance by implementing the function in C using the private _Py_normalize_encoding which has been modified to make lowercase conversion optional.

.. date: 2025-07-01-04-57-57 .. gh-issue: 136057 .. nonce: 4-t596 .. section: Library

Fixed the bug in :mod:pdb and :mod:bdb where next and step can't go over the line if a loop exists in the line.

.. date: 2025-06-29-22-01-00 .. gh-issue: 133390 .. nonce: I1DW_3 .. section: Library

Support table, index, trigger, view, column, function, and schema completion for :mod:sqlite3's :ref:command-line interface <sqlite3-cli>.

.. date: 2025-06-10-18-02-29 .. gh-issue: 135307 .. nonce: fXGrcK .. section: Library

:mod:email: Fix exception in set_content() when encoding text and max_line_length is set to 0 or None (unlimited).

.. date: 2025-05-10-15-10-54 .. gh-issue: 133789 .. nonce: I-ZlUX .. section: Library

Fix unpickling of :mod:pathlib objects that were pickled in Python 3.13.

.. date: 2025-05-07-22-09-28 .. gh-issue: 133601 .. nonce: 9kUL3P .. section: Library

Remove deprecated :func:!typing.no_type_check_decorator.

.. date: 2025-04-18-18-08-05 .. gh-issue: 132686 .. nonce: 6kV_Gs .. section: Library

Add parameters inherit_class_doc and fallback_to_class_doc for :func:inspect.getdoc.

.. date: 2025-03-12-18-57-10 .. gh-issue: 131116 .. nonce: uTpwXZ .. section: Library

:func:inspect.getdoc now correctly returns an inherited docstring on :class:~functools.cached_property objects if none is given in a subclass.

.. date: 2025-03-04-17-19-26 .. gh-issue: 130693 .. nonce: Kv01r8 .. section: Library

Add support for -nolinestop, and -strictlimits options to :meth:!tkinter.Text.search. Also add the :meth:!tkinter.Text.search_all method for -all and -overlap options.

.. date: 2024-08-08-12-39-36 .. gh-issue: 122255 .. nonce: J_gU8Y .. section: Library

In the :mod:linecache module and in the Python implementation of the :mod:warnings module, a DeprecationWarning is issued when mod.__loader__ differs from mod.__spec__.loader (like in the C implementation of the :mod:!warnings module).

.. date: 2024-06-26-16-16-43 .. gh-issue: 121011 .. nonce: qW54eh .. section: Library

:func:math.log now supports arbitrary large integer-like arguments in the same way as arbitrary large integer arguments.

.. date: 2024-05-28-17-14-30 .. gh-issue: 119668 .. nonce: RrIGpn .. section: Library

Publicly expose and document :class:importlib.machinery.NamespacePath.

.. date: 2023-03-21-10-59-40 .. gh-issue: 102431 .. nonce: eUDnf4 .. section: Library

Clarify constraints for "logical" arguments in methods of :class:decimal.Context.

.. date: 2019-06-02-13-56-16 .. gh-issue: 81313 .. nonce: axawSH .. section: Library

Add the :mod:math.integer module (:pep:791).

.. date: 2025-11-15-01-21-00 .. gh-issue: 141579 .. nonce: aB7cD9 .. section: Core and Builtins

Fix :func:sys.activate_stack_trampoline to properly support the perf_jit backend. Patch by Pablo Galindo.

.. date: 2025-11-14-16-25-15 .. gh-issue: 114203 .. nonce: n3tlQO .. section: Core and Builtins

Skip locking if object is already locked by two-mutex critical section.

.. date: 2025-11-14-00-19-45 .. gh-issue: 141528 .. nonce: VWdax1 .. section: Core and Builtins

Suggest using :meth:concurrent.interpreters.Interpreter.close instead of the private _interpreters.destroy function when warning about remaining subinterpreters. Patch by Sergey Miryanov.

.. date: 2025-11-11-13-40-45 .. gh-issue: 141367 .. nonce: I5KY7F .. section: Core and Builtins

Specialize CALL_LIST_APPEND instruction only for lists, not for list subclasses, to avoid unnecessary deopt. Patch by Mikhail Efimov.

.. date: 2025-11-10-23-07-06 .. gh-issue: 141312 .. nonce: H-58GB .. section: Core and Builtins

Fix the assertion failure in the __setstate__ method of the range iterator when a non-integer argument is passed. Patch by Sergey Miryanov.

.. date: 2025-11-05-19-50-37 .. gh-issue: 140643 .. nonce: QCEOqG .. section: Core and Builtins

Add support for <GC> and <native> frames to :mod:!profiling.sampling output to denote active garbage collection and calls to native code.

.. date: 2025-11-04-12-18-06 .. gh-issue: 140942 .. nonce: GYns6n .. section: Library

Add .cjs to :mod:mimetypes to give CommonJS modules a MIME type of application/node.

.. date: 2025-11-04-04-57-24 .. gh-issue: 140479 .. nonce: lwQ2v2 .. section: Core and Builtins

Update JIT compilation to use LLVM 21 at build time.

.. date: 2025-11-03-17-21-38 .. gh-issue: 140939 .. nonce: FVboAw .. section: Core and Builtins

Fix memory leak when :class:bytearray or :class:bytes is formated with the %*b format with a large width that results in a :exc:MemoryError.

.. date: 2025-11-02-15-28-33 .. gh-issue: 140260 .. nonce: JNzlGz .. section: Library

Fix :mod:struct data race in endian table initialization with subinterpreters. Patch by Shamil Abdulaev.

.. date: 2025-11-02-12-47-38 .. gh-issue: 140530 .. nonce: S934bp .. section: Core and Builtins

Fix a reference leak when raise exc from cause fails. Patch by Bénédikt Tran.

.. date: 2025-10-31-14-03-42 .. gh-issue: 90344 .. nonce: gvZigO .. section: Library

Replace :class:io.IncrementalNewlineDecoder with non incremental newline decoders in codebase where :meth:!io.IncrementalNewlineDecoder.decode was being called once.

.. date: 2025-10-29-20-59-10 .. gh-issue: 140373 .. nonce: -uoaPP .. section: Core and Builtins

Correctly emit PY_UNWIND event when generator object is closed. Patch by Mikhail Efimov.

.. date: 2025-10-29-11-31-59 .. gh-issue: 140729 .. nonce: t9JsNt .. section: Core and Builtins

Fix pickling error in the sampling profiler when using concurrent.futures.ProcessPoolExecutor script can not be properly pickled and executed in worker processes.

.. date: 2025-10-25-21-31-43 .. gh-issue: 131527 .. nonce: V-JVNP .. section: Core and Builtins

Dynamic borrow checking for stackrefs is added to Py_STACKREF_DEBUG mode. Patch by Mikhail Efimov.

.. date: 2025-10-25-17-36-46 .. gh-issue: 140576 .. nonce: kj0SCY .. section: Core and Builtins

Fixed crash in :func:tokenize.generate_tokens in case of specific incorrect input. Patch by Mikhail Efimov.

.. date: 2025-10-25-07-25-52 .. gh-issue: 140544 .. nonce: lwjtQe .. section: Core and Builtins

Speed up accessing interpreter state by caching it in a thread local variable. Patch by Kumar Aditya.

.. date: 2025-10-24-20-42-33 .. gh-issue: 140551 .. nonce: -9swrl .. section: Core and Builtins

Fixed crash in :class:dict if :meth:dict.clear is called at the lookup stage. Patch by Mikhail Efimov and Inada Naoki.

.. date: 2025-10-24-20-16-42 .. gh-issue: 140517 .. nonce: cqun-K .. section: Core and Builtins

Fixed a reference leak when iterating over the result of :func:map with strict=True when the input iterables have different lengths. Patch by Mikhail Efimov.

.. date: 2025-10-24-14-29-12 .. gh-issue: 133467 .. nonce: A5d6TM .. section: Core and Builtins

Fix race when updating :attr:!type.__bases__ that could allow a read of :attr:!type.__base__ to observe an inconsistent value on the free threaded build.

.. date: 2025-10-23-16-05-50 .. gh-issue: 140471 .. nonce: Ax_aXn .. section: Core and Builtins

Fix potential buffer overflow in :class:ast.AST node initialization when encountering malformed :attr:~ast.AST._fields containing non-:class:str.

.. date: 2025-10-22-23-26-37 .. gh-issue: 140443 .. nonce: wT5i1A .. section: Library

The logarithm functions (such as :func:math.log10 and :func:math.log) may now produce slightly different results for extremely large integers that cannot be converted to floats without overflow. These results are generally more accurate, with reduced worst-case error and a tighter overall error distribution.

.. date: 2025-10-22-17-22-22 .. gh-issue: 140431 .. nonce: m8D_A- .. section: Core and Builtins

Fix a crash in Python's :term:garbage collector <garbage collection> due to partially initialized :term:coroutine objects when coroutine origin tracking depth is enabled (:func:sys.set_coroutine_origin_tracking_depth).

.. date: 2025-10-22-12-48-05 .. gh-issue: 140476 .. nonce: F3-d1P .. section: Core and Builtins

Optimize :c:func:PySet_Add for :class:frozenset in :term:free threaded <free threading> build.

.. date: 2025-10-22-11-30-16 .. gh-issue: 135904 .. nonce: 3WE5oW .. section: Core and Builtins

Add special labels to the assembly created during stencil creation to support relocations that the native object file format does not support. Specifically, 19 bit branches for AArch64 in Mach-O object files.

.. date: 2025-10-21-09-20-03 .. gh-issue: 140398 .. nonce: SoABwJ .. section: Library

Fix memory leaks in :mod:readline functions :func:~readline.read_init_file, :func:~readline.read_history_file, :func:~readline.write_history_file, and :func:~readline.append_history_file when :c:func:PySys_Audit fails.

.. date: 2025-10-21-06-51-50 .. gh-issue: 140406 .. nonce: 0gJs8M .. section: Core and Builtins

Fix memory leak when an object's :meth:~object.__hash__ method returns an object that isn't an :class:int.

.. date: 2025-10-20-11-24-36 .. gh-issue: 140358 .. nonce: UQuKdV .. section: Core and Builtins

Restore elapsed time and unreachable object count in GC debug output. These were inadvertently removed during a refactor of gc.c. The debug log now again reports elapsed collection time and the number of unreachable objects. Contributed by Pål Grønås Drange.

.. date: 2025-10-19-10-32-28 .. gh-issue: 136895 .. nonce: HfsEh0 .. section: Core and Builtins

Update JIT compilation to use LLVM 20 at build time.

.. date: 2025-10-18-21-50-44 .. gh-issue: 139109 .. nonce: 9QQOzN .. section: Core and Builtins

A new tracing frontend for the JIT compiler has been implemented. Patch by Ken Jin. Design for CPython by Ken Jin, Mark Shannon and Brandt Bucher.

.. date: 2025-10-18-21-29-45 .. gh-issue: 140306 .. nonce: xS5CcS .. section: Core and Builtins

Fix memory leaks in cross-interpreter channel operations and shared namespace handling.

.. date: 2025-10-18-19-52-20 .. gh-issue: 116738 .. nonce: NLJW0L .. section: Core and Builtins

Make _suggestions module thread-safe on the :term:free threaded <free threading> build.

.. date: 2025-10-18-18-08-36 .. gh-issue: 140301 .. nonce: m-2HxC .. section: Core and Builtins

Fix memory leak of PyConfig in subinterpreters.

.. date: 2025-10-17-20-23-19 .. gh-issue: 140257 .. nonce: 8Txmem .. section: Core and Builtins

Fix data race between interpreter_clear() and take_gil() on eval_breaker during finalization with daemon threads.

.. date: 2025-10-17-18-03-12 .. gh-issue: 139951 .. nonce: IdwM2O .. section: Core and Builtins

Fixes a regression in GC performance for a growing heap composed mostly of small tuples.

Counts number of actually tracked objects, instead of trackable objects. This ensures that untracking tuples has the desired effect of reducing GC overhead.
Does not track most untrackable tuples during creation. This prevents large numbers of small tuples causing excessive GCs.

.. date: 2025-10-17-14-38-10 .. gh-issue: 140253 .. nonce: gCqFaL .. section: Core and Builtins

Wrong placement of a double-star pattern inside a mapping pattern now throws a specialized syntax error. Contributed by Bartosz Sławecki in :gh:140253.

.. date: 2025-10-16-21-47-00 .. gh-issue: 140104 .. nonce: A8SQIm .. section: Core and Builtins

Fix a bug with exception handling in the JIT. Patch by Ken Jin. Bug reported by Daniel Diniz.

.. date: 2025-10-15-17-12-32 .. gh-issue: 140149 .. nonce: cy1m3d .. section: Core and Builtins

Speed up parsing bytes literals concatenation by using PyBytesWriter API and a single memory allocation (about 3x faster).

.. date: 2025-10-15-00-21-40 .. gh-issue: 140061 .. nonce: J0XeDV .. section: Core and Builtins

Fixing the checking of whether an object is uniquely referenced to ensure free-threaded compatibility. Patch by Sergey Miryanov.

.. date: 2025-10-14-20-18-31 .. gh-issue: 140080 .. nonce: 8ROjxW .. section: Core and Builtins

Fix hang during finalization when attempting to call :mod:atexit handlers under no memory.

.. date: 2025-10-14-18-24-16 .. gh-issue: 139871 .. nonce: SWtuUz .. section: Core and Builtins

Update :class:bytearray to use a :class:bytes under the hood as its buffer and add :meth:bytearray.take_bytes to take it out.

.. date: 2025-10-14-17-07-37 .. gh-issue: 140067 .. nonce: ID2gOm .. section: Core and Builtins

Fix memory leak in sub-interpreter creation.

.. date: 2025-10-13-13-54-19 .. gh-issue: 139914 .. nonce: M-y_3E .. section: Core and Builtins

Restore support for HP PA-RISC, which has an upwards-growing stack.

.. date: 2025-10-12-01-12-12 .. gh-issue: 139817 .. nonce: PAn-8Z .. section: Core and Builtins

Attribute __qualname__ is added to :class:typing.TypeAliasType. Patch by Mikhail Efimov.

.. date: 2025-10-06-14-19-47 .. gh-issue: 135801 .. nonce: OhxEZS .. section: Core and Builtins

Many functions related to compiling or parsing Python code, such as :func:compile, :func:ast.parse, :func:symtable.symtable, and :func:importlib.abc.InspectLoader.source_to_code now allow to specify the module name. It is needed to unambiguous :ref:filter <warning-filter> syntax warnings by module name.

.. date: 2025-10-06-10-03-37 .. gh-issue: 139640 .. nonce: gY5oTb2 .. section: Core and Builtins

:func:ast.parse no longer emits syntax warnings for return/break/continue in finally (see :pep:765) -- they are only emitted during compilation.

.. date: 2025-10-06-10-03-37 .. gh-issue: 139640 .. nonce: gY5oTb .. section: Core and Builtins

Fix swallowing some syntax warnings in different modules if they accidentally have the same message and are emitted from the same line. Fix duplicated warnings in the finally block.

.. date: 2025-10-03-17-51-43 .. gh-issue: 139475 .. nonce: _684ED .. section: Core and Builtins

Changes in stackref debugging mode when Py_STACKREF_DEBUG is set. We use the same pattern of refcounting for stackrefs as in production build.

.. date: 2025-09-23-21-01-12 .. gh-issue: 139269 .. nonce: 1rIaxy .. section: Core and Builtins

Fix undefined behavior when using unaligned store in JIT's patch_* functions.

.. date: 2025-09-15-13-06-11 .. gh-issue: 138944 .. nonce: PeCgLb .. section: Core and Builtins

Fix :exc:SyntaxError message when invalid syntax appears on the same line as a valid import ... as ... or from ... import ... as ... statement. Patch by Brian Schubert.

.. date: 2025-09-13-01-23-25 .. gh-issue: 138857 .. nonce: YQ5gdc .. section: Core and Builtins

Improve :exc:SyntaxError message for case keyword placed outside :keyword:match body.

.. date: 2025-07-29-17-51-14 .. gh-issue: 131253 .. nonce: GpRjWy .. section: Core and Builtins

Support the --enable-pystats build option for the free-threaded build.

.. date: 2025-07-08-00-41-46 .. gh-issue: 136327 .. nonce: 7AiTb_ .. section: Core and Builtins

Errors when calling functions with invalid values after * and ** now do not include the function name. Patch by Ilia Solin.

.. date: 2025-06-24-13-12-58 .. gh-issue: 134786 .. nonce: MF0VVk .. section: Core and Builtins

If :c:macro:Py_TPFLAGS_MANAGED_DICT and :c:macro:Py_TPFLAGS_MANAGED_WEAKREF are used, then :c:macro:Py_TPFLAGS_HAVE_GC must be used as well.

.. date: 2025-11-10-11-26-26 .. gh-issue: 141341 .. nonce: OsO6-y .. section: C API

On Windows, rename the COMPILER macro to _Py_COMPILER to avoid name conflicts. Patch by Victor Stinner.

.. date: 2025-11-08-10-51-50 .. gh-issue: 116146 .. nonce: pCmx6L .. section: C API

Add a new :c:func:PyImport_CreateModuleFromInitfunc C-API for creating a module from a spec and initfunc. Patch by Itamar Oren.

.. date: 2025-11-06-06-28-14 .. gh-issue: 141042 .. nonce: brOioJ .. section: C API

Make qNaN in :c:func:PyFloat_Pack2 and :c:func:PyFloat_Pack4, if while conversion to a narrower precision floating-point format --- the remaining after truncation payload will be zero. Patch by Sergey B Kirpichev.

.. date: 2025-11-05-05-45-49 .. gh-issue: 141004 .. nonce: N9Ooh9 .. section: C API

:c:macro:!Py_MATH_El and :c:macro:!Py_MATH_PIl are deprecated.

.. date: 2025-11-05-04-38-16 .. gh-issue: 141004 .. nonce: rJL43P .. section: C API

The :c:macro:!Py_INFINITY macro is :term:soft deprecated.

.. date: 2025-10-26-16-45-28 .. gh-issue: 140556 .. nonce: s__Dae .. section: C API

:pep:793: Add a new entry point for C extension modules, PyModExport_<modulename>.

.. date: 2025-10-26-16-45-06 .. gh-issue: 140487 .. nonce: fGOqss .. section: C API

Fix :c:macro:Py_RETURN_NOTIMPLEMENTED in limited C API 3.11 and older: don't treat Py_NotImplemented as immortal. Patch by Victor Stinner.

.. date: 2025-10-15-15-59-59 .. gh-issue: 140153 .. nonce: BO7sH4 .. section: C API

Fix :c:func:Py_REFCNT definition on limited C API 3.11-3.13. Patch by Victor Stinner.

.. date: 2025-10-06-22-17-47 .. gh-issue: 139653 .. nonce: 6-1MOd .. section: C API

Add :c:func:PyUnstable_ThreadState_SetStackProtection and :c:func:PyUnstable_ThreadState_ResetStackProtection functions to set the stack protection base address and stack protection size of a Python thread state. Patch by Victor Stinner.

.. date: 2025-10-31-13-20-16 .. gh-issue: 140454 .. nonce: gF6dCe .. section: Build

When building the JIT, match the jit_stencils filename expectations in Makefile with the generator script. This avoid needless JIT recompilation during make install.

.. date: 2025-10-29-12-30-38 .. gh-issue: 140768 .. nonce: ITYrzw .. section: Build

Warn when the WASI SDK version doesn't match what's supported.

.. date: 2025-10-25-08-07-06 .. gh-issue: 140513 .. nonce: 6OhLTs .. section: Build

Generate a clear compilation error when _Py_TAIL_CALL_INTERP is enabled but either preserve_none or musttail is not supported.

.. date: 2025-10-22-12-44-07 .. gh-issue: 140475 .. nonce: OhzQbR .. section: Build

Support WASI SDK 25.

.. date: 2025-10-17-11-33-45 .. gh-issue: 140239 .. nonce: _k-GgW .. section: Build

Check statx availability only on Linux (including Android).

.. date: 2025-10-16-11-30-53 .. gh-issue: 140189 .. nonce: YCrUyt .. section: Build

iOS builds were added to CI.

.. date: 2025-08-10-22-28-06 .. gh-issue: 137618 .. nonce: FdNvIE .. section: Build

PYTHON_FOR_REGEN now requires Python 3.10 to Python 3.15. Patch by Adam Turner.