Misc/NEWS.d/3.15.0a6.rst

.. date: 2026-02-10-08-00-17
.. gh-issue: 144648
.. nonce: KEuUXp
.. release date: 2026-02-11
.. section: macOS

Allowed _remote_debugging to build on more OS versions by using
proc_listpids() rather than proc_listallpids().

..

.. date: 2026-02-09-23-01-49
.. gh-issue: 124111
.. nonce: WmQG7S
.. section: macOS

Update macOS installer to use Tcl/Tk 9.0.3.

..

.. date: 2026-02-09-22-43-47
.. gh-issue: 144551
.. nonce: VOfgfD
.. section: macOS

Update macOS installer to use OpenSSL 3.5.5.

..

.. date: 2026-01-05-21-36-58
.. gh-issue: 80620
.. nonce: p1bD58
.. section: Windows

Support negative timestamps in :func:`time.gmtime`, :func:`time.localtime`,
and various :mod:`datetime` functions.

..

.. date: 2026-02-03-07-57-24
.. gh-issue: 144415
.. nonce: U3L15r
.. section: Tests

The Android testbed now distinguishes between stdout/stderr messages which
were triggered by a newline, and those triggered by a manual call to
``flush``. This fixes logging of progress indicators and similar content.

..

.. date: 2026-01-08-16-56-59
.. gh-issue: 65784
.. nonce: aKNo1U
.. section: Tests

Add support for parametrized resource ``wantobjects`` in regrtests, which
allows to run Tkinter tests with the specified value of
:data:`!tkinter.wantobjects`, for example ``-u wantobjects=0``.

..

.. date: 2026-01-21-12-34-05
.. gh-issue: 144125
.. nonce: TAz5uo
.. section: Security

:mod:`~email.generator.BytesGenerator` will now refuse to serialize (write)
headers that are unsafely folded or delimited; see
:attr:`~email.policy.Policy.verify_generated_headers`. (Contributed by Bas
Bloemsaat and Petr Viktorin in :gh:`121650`).

..

.. date: 2026-01-16-14-40-31
.. gh-issue: 143935
.. nonce: U2YtKl
.. section: Security

Fixed a bug in the folding of comments when flattening an email message
using a modern email policy. Comments consisting of a very long sequence of
non-foldable characters could trigger a forced line wrap that omitted the
required leading space on the continuation line, causing the remainder of
the comment to be interpreted as a new header field. This enabled header
injection with carefully crafted inputs.

..

.. date: 2026-01-16-11-51-19
.. gh-issue: 143925
.. nonce: mrtcHW
.. section: Security

Reject control characters in ``data:`` URL media types.

..

.. date: 2026-01-16-11-43-47
.. gh-issue: 143923
.. nonce: DuytMe
.. section: Security

Reject control characters in POP3 commands.

..

.. date: 2026-01-16-11-41-06
.. gh-issue: 143921
.. nonce: AeCOor
.. section: Security

Reject control characters in IMAP commands.

..

.. date: 2026-01-16-11-13-15
.. gh-issue: 143919
.. nonce: kchwZV
.. section: Security

Reject control characters in :class:`http.cookies.Morsel` fields and values.

..

.. date: 2026-01-16-11-07-36
.. gh-issue: 143916
.. nonce: dpWeOD
.. section: Security

Reject C0 control characters within wsgiref.headers.Headers fields, values,
and parameters.

..

.. date: 2026-02-06-23-58-54
.. gh-issue: 144538
.. nonce: 5_OvGv
.. section: Library

Bump the version of pip bundled in ensurepip to version 26.0.1

..

.. date: 2026-02-05-17-15-31
.. gh-issue: 144493
.. nonce: XuxwVu
.. section: Library

Improve an exception error message in ``_overlapped.BindLocal()`` that is
raised when :meth:`asyncio.loop.sock_connect` is called on a
:class:`asyncio.ProactorEventLoop` with a socket that has an invalid address
family.

..

.. date: 2026-02-03-14-16-49
.. gh-issue: 144386
.. nonce: 9Wa59r
.. section: Library

Add support for arbitrary descriptors :meth:`!__enter__`, :meth:`!__exit__`,
:meth:`!__aenter__`, and :meth:`!__aexit__` in :class:`contextlib.ExitStack`
and :class:`contextlib.AsyncExitStack`, for consistency with the
:keyword:`with` and :keyword:`async with` statements.

..

.. date: 2026-02-03-08-50-58
.. gh-issue: 123471
.. nonce: yF1Gym
.. section: Library

Make concurrent iteration over
:class:`itertools.combinations_with_replacement` and
:class:`itertools.permutations` safe under free-threading.

..

.. date: 2026-02-02-12-09-38
.. gh-issue: 74453
.. nonce: 19h4Z5
.. section: Library

Deprecate :func:`os.path.commonprefix` in favor of
:func:`os.path.commonpath` for path segment prefixes.

The :func:`os.path.commonprefix` function is being deprecated due to having
a misleading name and module. The function is not safe to use for path
prefixes despite being included in a module about path manipulation, meaning
it is easy to accidentally introduce path traversal vulnerabilities into
Python programs by using this function.

..

.. date: 2026-02-01-15-25-00
.. gh-issue: 144380
.. nonce: U7py_s
.. section: Library

Improve performance of :class:`io.BufferedReader` line iteration by ~49%.

..

.. date: 2026-01-31-17-15-49
.. gh-issue: 144363
.. nonce: X9f0sU
.. section: Library

Update bundled `libexpat <https://libexpat.github.io/>`_ to 2.7.4

..

.. date: 2026-01-30-13-23-06
.. gh-issue: 140824
.. nonce: J1OCrC
.. section: Library

When :mod:`faulthandler` dumps the list of third-party extension modules,
ignore sub-modules of stdlib packages. Patch by Victor Stinner.

..

.. date: 2026-01-27-14-23-10
.. gh-issue: 144206
.. nonce: l0un4U
.. section: Library

Improve error messages for buffer overflow in :func:`fcntl.fcntl` and
:func:`fcntl.ioctl`.

..

.. date: 2026-01-27-10-02-04
.. gh-issue: 144264
.. nonce: Wmzbol
.. section: Library

Speed up Base64 decoding of data containing ignored characters (both in
non-strict mode and with an explicit *ignorechars* argument). It is now up
to 2 times faster for multiline Base64 data.

..

.. date: 2026-01-27-09-58-52
.. gh-issue: 144249
.. nonce: mCIy95
.. section: Library

Add filename context to :exc:`OSError` exceptions raised by
:func:`ssl.SSLContext.load_cert_chain`, allowing users to have more context.

..

.. date: 2026-01-27-00-03-41
.. gh-issue: 132888
.. nonce: yhTfUN
.. section: Library

Fix incorrect use of :func:`ctypes.GetLastError` and add missing error
checks for Windows API calls in :mod:`!_pyrepl.windows_console`.

..

.. date: 2026-01-26-12-30-57
.. gh-issue: 142956
.. nonce: X9CS8J
.. section: Library

Updated :mod:`tomllib` to parse TOML 1.1.0.

..

.. date: 2026-01-25-03-23-20
.. gh-issue: 144217
.. nonce: E1wVXH
.. section: Library

:mod:`mimetypes`: Add support for DICOM files (for medical imaging) with the
official MIME type ``application/dicom``. Patch by Benedikt Johannes.

..

.. date: 2026-01-24-23-11-17
.. gh-issue: 144212
.. nonce: IXqVL8
.. section: Library

Mime type ``image/jxl`` is now supported by :mod:`mimetypes`.

..

.. date: 2026-01-24-13-49-05
.. gh-issue: 143594
.. nonce: nilGlg
.. section: Library

Add :meth:`symtable.Function.get_cells` and :meth:`symtable.Symbol.is_cell`
methods.

..

.. date: 2026-01-23-06-43-21
.. gh-issue: 144169
.. nonce: LFy9yi
.. section: Library

Fix three crashes when non-string keyword arguments are supplied to objects
in the :mod:`ast` module.

..

.. date: 2026-01-22-10-18-17
.. gh-issue: 144128
.. nonce: akwY06
.. section: Library

Fix a crash in :meth:`array.array.fromlist` when an element's
:meth:`~object.__index__` method mutates the input list during conversion.

..

.. date: 2026-01-21-19-39-07
.. gh-issue: 144100
.. nonce: hLMZ8Y
.. section: Library

Fixed a crash in ctypes when using a deprecated ``POINTER(str)`` type in
``argtypes``. Instead of aborting, ctypes now raises a proper Python
exception when the pointer target type is unresolved.

..

.. date: 2026-01-20-20-54-46
.. gh-issue: 143658
.. nonce: v8i1jE
.. section: Library

:mod:`importlib.metadata`: Use :meth:`str.lower` and :meth:`str.replace` to
further improve performance of
:meth:`!importlib.metadata.Prepared.normalize`. Patch by Hugo van Kemenade
and Henry Schreiner.

..

.. date: 2026-01-20-16-35-55
.. gh-issue: 144050
.. nonce: 0kKFbF
.. section: Library

Fix :func:`stat.filemode` in the pure-Python implementation to avoid
misclassifying invalid mode values as block devices.

..

.. date: 2026-01-19-16-45-16
.. gh-issue: 83069
.. nonce: 0TaeH9
.. section: Library

:meth:`subprocess.Popen.wait`: when ``timeout`` is not ``None``, an
efficient event-driven mechanism now waits for process termination, if
available. Linux >= 5.3 uses :func:`os.pidfd_open` + :func:`select.poll`.
macOS and other BSD variants use :func:`select.kqueue` + ``KQ_FILTER_PROC``
+ ``KQ_NOTE_EXIT``. Windows keeps using ``WaitForSingleObject`` (unchanged).
If none of these mechanisms are available, the function falls back to the
traditional busy loop (non-blocking call and short sleeps). Patch by
Giampaolo Rodola.

..

.. date: 2026-01-19-12-48-59
.. gh-issue: 144030
.. nonce: 7OK_gB
.. section: Library

The Python implementation of :func:`functools.lru_cache` differed from the
default C implementation in that it did not check that its argument is
callable. This discrepancy is now fixed and both raise a :exc:`TypeError`.

..

.. date: 2026-01-19-10-26-59
.. gh-issue: 144001
.. nonce: dGj8Nk
.. section: Library

Added the *ignorechars* parameter in :func:`binascii.a2b_base64` and
:func:`base64.b64decode`.

..

.. date: 2026-01-19-00-57-40
.. gh-issue: 144023
.. nonce: 29XUcp
.. section: Library

Fixed validation of file descriptor 0 in posix functions when used with
follow_symlinks parameter.

..

.. date: 2026-01-18-14-35-37
.. gh-issue: 143999
.. nonce: MneN4O
.. section: Library

Fix an issue where :func:`inspect.getgeneratorstate` and
:func:`inspect.getcoroutinestate` could fail for generators wrapped by
:func:`types.coroutine` in the suspended state.

..

.. date: 2026-01-17-07-48-27
.. gh-issue: 143952
.. nonce: lqJ55y
.. section: Library

Fixed :mod:`asyncio` debugging tools to work with new remote debugging API.
Patch by Bartosz Sławecki.

..

.. date: 2026-01-16-14-02-39
.. gh-issue: 143904
.. nonce: rErHHA
.. section: Library

:func:`struct.pack_into` now raises OverflowError instead of IndexError for
too large *offset* argument.

..

.. date: 2026-01-16-10-53-17
.. gh-issue: 143897
.. nonce: hWJBHN
.. section: Library

Remove the :meth:`!isxidstart` and :meth:`!isxidcontinue` methods of
:data:`unicodedata.ucd_3_2_0`. They are now only exposed as
:func:`unicodedata.isxidstart` and :func:`unicodedata.isxidcontinue`.

..

.. date: 2026-01-16-06-22-10
.. gh-issue: 143831
.. nonce: VLBTLp
.. section: Library

:class:`annotationlib.ForwardRef` objects are now hashable when created from
annotation scopes with closures. Previously, hashing such objects would
throw an exception. Patch by Bartosz Sławecki.

..

.. date: 2026-01-15-16-04-39
.. gh-issue: 143874
.. nonce: 1qQgvo
.. section: Library

Fixed a bug in :mod:`pdb` where expression results were not sent back to
remote client.

..

.. date: 2026-01-14-20-35-40
.. gh-issue: 143754
.. nonce: m2NQXA
.. section: Library

Add new :mod:`tkinter` widget methods :meth:`!pack_content`,
:meth:`!place_content` and :meth:`!grid_content` which are alternative
spelling of old :meth:`!*_slaves` methods.

..

.. date: 2026-01-13-16-19-50
.. gh-issue: 143756
.. nonce: LQOra1
.. section: Library

Fix potential thread safety issues in :mod:`ssl` module.

..

.. date: 2026-01-13-15-56-03
.. gh-issue: 132604
.. nonce: lvjNTr
.. section: Library

Previously, :class:`~typing.Protocol` classes that were not decorated with
:deco:`~typing.runtime_checkable`, but that inherited from another
``Protocol`` class that did have this decorator, could be used in
:func:`isinstance` and :func:`issubclass` checks. This behavior is now
deprecated and such checks will throw a :exc:`TypeError` in Python 3.20.
Patch by Bartosz Sławecki.

..

.. date: 2026-01-13-10-38-43
.. gh-issue: 143543
.. nonce: DeQRCO
.. section: Library

Fix a crash in itertools.groupby that could occur when a user-defined
:meth:`~object.__eq__` method re-enters the iterator during key comparison.

..

.. date: 2026-01-11-14-14-19
.. gh-issue: 143689
.. nonce: fzHJ2W
.. section: Library

Fix :meth:`io.BufferedReader.read1` state cleanup on buffer allocation
failure.

..

.. date: 2026-01-09-12-37-19
.. gh-issue: 143602
.. nonce: V8vQpj
.. section: Library

Fix a inconsistency issue in :meth:`~io.RawIOBase.write` that leads to
unexpected buffer overwrite by deduplicating the buffer exports.

..

.. date: 2026-01-07-19-01-59
.. gh-issue: 142434
.. nonce: SHRS5p
.. section: Library

Use ``ppoll()`` if available in :func:`select.poll` to have a timeout
resolution of 1 nanosecond, instead of a resolution of 1 ms. Patch by Victor
Stinner.

..

.. date: 2026-01-07-11-57-59
.. gh-issue: 140557
.. nonce: 3P6-nW
.. section: Library

:class:`array.array` buffers now have the same alignment when empty as when
allocated. Unaligned buffers can still be created by slicing.

..

.. date: 2026-01-05-05-31-05
.. gh-issue: 143423
.. nonce: X7YdnR
.. section: Library

Fix free-threaded build detection in the sampling profiler when
Py_GIL_DISABLED is set to 0.

..

.. date: 2025-12-28-15-55-53
.. gh-issue: 101178
.. nonce: 26jYPs
.. section: Library

Add Ascii85, Base85, and Z85 support to :mod:`binascii` and improve the
performance of the base-85 converters in :mod:`base64`.

..

.. date: 2025-12-19-11-30-31
.. gh-issue: 142966
.. nonce: PzGiv2
.. section: Library

Fix :func:`!ctypes.POINTER.set_type` not updating the format string to match
the type.

..

.. date: 2025-12-15-02-02-45
.. gh-issue: 142555
.. nonce: EC9QN_
.. section: Library

:mod:`array`: fix a crash in ``a[i] = v`` when converting *i* to an index
via :meth:`i.__index__ <object.__index__>` or :meth:`i.__float__
<object.__float__>` mutates the array.

..

.. date: 2025-12-08-18-40-17
.. gh-issue: 142438
.. nonce: tH-Y16
.. section: Library

Fix _decimal builds configured with EXTRA_FUNCTIONALITY by correcting the
Context.apply wrapper to pass the right argument.

..

.. date: 2025-11-22-20-30-00
.. gh-issue: 141860
.. nonce: frksvr
.. section: Library

Add an ``on_error`` keyword-only parameter to
:func:`multiprocessing.set_forkserver_preload` to control how import
failures during module preloading are handled. Accepts ``'ignore'``
(default, silent), ``'warn'`` (emit :exc:`ImportWarning`), or ``'fail'``
(raise exception). Contributed by Nick Neumann and Gregory P. Smith.

..

.. date: 2025-11-06-12-03-29
.. gh-issue: 125346
.. nonce: 7Gfpgw
.. section: Library

Accepting ``+`` and ``/`` characters with an alternative alphabet in
:func:`base64.b64decode` and :func:`base64.urlsafe_b64decode` is now
deprecated. In future Python versions they will be errors in the strict mode
and discarded in the non-strict mode.

..

.. date: 2025-10-27-00-13-04
.. gh-issue: 140715
.. nonce: WkozE0
.. section: Library

Add ``'%F'`` support to :meth:`~datetime.datetime.strptime`.

..

.. date: 2024-11-27-13-11-16
.. gh-issue: 67041
.. nonce: ym2WKK
.. section: Library

Add the *missing_as_none* parameter to :func:`~urllib.parse.urlparse`,
:func:`~urllib.parse.urlsplit` and :func:`~urllib.parse.urldefrag`
functions. Add the *keep_empty* parameter to
:func:`~urllib.parse.urlunparse` and :func:`~urllib.parse.urlunsplit`
functions. This allows to distinguish between empty and not defined URI
components and preserve empty components.

..

.. date: 2020-07-14-23-54-18
.. gh-issue: 77188
.. nonce: TyI3_Q
.. section: Library

The :mod:`pickle` module now properly handles name-mangled private methods.

..

.. date: 2026-01-13-01-21-20
.. gh-issue: 143774
.. nonce: rqGwX1
.. section: IDLE

Better explain the operation of Format / Format Paragraph.

..

.. date: 2026-02-10-12-08-58
.. gh-issue: 134584
.. nonce: P9LDy5
.. section: Core and Builtins

Optimize and eliminate ref-counting in ``_BINARY_OP_SUBSCR_LIST_SLICE``

..

.. date: 2026-02-08-18-13-38
.. gh-issue: 144563
.. nonce: hb3kpp
.. section: Core and Builtins

Fix interaction of the Tachyon profiler and :mod:`ctypes` and other modules
that load the Python shared library (if present) in an independent map as
this was causing the mechanism that loads the binary information to be
confused. Patch by Pablo Galindo

..

.. date: 2026-02-08-12-47-27
.. gh-issue: 144601
.. nonce: E4Yi9J
.. section: Core and Builtins

Fix crash when importing a module whose ``PyInit`` function raises an
exception from a subinterpreter.

..

.. date: 2026-02-06-17-59-47
.. gh-issue: 144549
.. nonce: 5BhPlY
.. section: Core and Builtins

Fix building the tail calling interpreter on Visual Studio 2026 with
free-threading.

..

.. date: 2026-02-05-13-30-00
.. gh-issue: 144513
.. nonce: IjSTd7
.. section: Core and Builtins

Fix potential deadlock when using critical sections during stop-the-world
pauses in the free-threaded build.

..

.. date: 2026-02-04-12-19-48
.. gh-issue: 131798
.. nonce: My5jLy
.. section: Core and Builtins

Optimise ``_GUARD_TOS_SLICE`` in the JIT.

..

.. date: 2026-02-04-11-19-45
.. gh-issue: 144330
.. nonce: kOowSb
.. section: Core and Builtins

Move ``classmethod`` and ``staticmethod`` initialization from ``__init__()``
to ``__new__()``. Patch by Victor Stinner.

..

.. date: 2026-02-03-17-08-13
.. gh-issue: 144446
.. nonce: db5619
.. section: Core and Builtins

Fix data races in the free-threaded build when reading frame object
attributes while another thread is executing the frame.

..

.. date: 2026-02-02-17-50-14
.. gh-issue: 120321
.. nonce: Xfr7tL
.. section: Core and Builtins

Add ``gi_state``, ``cr_state``, and ``ag_state`` attributes to generators,
coroutines, and async generators that return the current state as a string
(e.g., ``GEN_RUNNING``). The :mod:`inspect` module functions
:func:`~inspect.getgeneratorstate`, :func:`~inspect.getcoroutinestate`, and
:func:`~inspect.getasyncgenstate` now return these attributes directly.

..

.. date: 2026-02-02-17-07-34
.. gh-issue: 141563
.. nonce: GheXjr
.. section: Core and Builtins

Fix thread safety of :c:macro:`! PyDateTime_IMPORT`.

..

.. date: 2026-01-30-15-54-50
.. gh-issue: 144280
.. nonce: kgiP5R
.. section: Core and Builtins

Fix a bug in JIT where the predicate symbol had no truthiness

..

.. date: 2026-01-30-10-38-07
.. gh-issue: 140550
.. nonce: Us9vPD
.. section: Core and Builtins

In :c:member:`PyModuleDef.m_slots`, allow slots that repeat information
present in :c:type:`PyModuleDef`.

..

.. date: 2026-01-29-16-57-11
.. gh-issue: 139103
.. nonce: icXIEQ
.. section: Core and Builtins

Improve scaling of :func:`~collections.namedtuple` instantiation in the
free-threaded build.

..

.. date: 2026-01-29-02-18-08
.. gh-issue: 144307
.. nonce: CLbm_o
.. section: Core and Builtins

Prevent a reference leak in module teardown at interpreter finalization.

..

.. date: 2026-01-29-01-42-14
.. gh-issue: 144319
.. nonce: _7EtdB
.. section: Core and Builtins

Add huge pages support for the pymalloc allocator. Patch by Pablo Galindo

..

.. date: 2026-01-27-17-49-43
.. gh-issue: 120321
.. nonce: Vo7c9T
.. section: Core and Builtins

Made ``gi_yieldfrom`` thread-safe in the free-threading build by using a
lightweight lock on the frame state.

..

.. date: 2026-01-23-20-20-42
.. gh-issue: 144194
.. nonce: IbXfxd
.. section: Core and Builtins

Fix error handling in perf jitdump initialization on memory allocation
failure.

..

.. date: 2026-01-22-17-04-30
.. gh-issue: 143962
.. nonce: dQR1a9
.. section: Core and Builtins

Name suggestion for not normalized name suggests now the normalized name or
the closest name to the normalized name. If the suggested name is not ASCII,
include also its ASCII representation.

..

.. date: 2026-01-22-16-20-16
.. gh-issue: 144157
.. nonce: dxyp7k
.. section: Core and Builtins

:meth:`bytes.translate` now allows the compiler to unroll its loop more
usefully for a 2x speedup in the common no-deletions specified case.

..

.. date: 2026-01-21-02-30-06
.. gh-issue: 144068
.. nonce: 9TTu7v
.. section: Core and Builtins

Fix JIT tracer memory leak, ensure the JIT tracer state is freed when daemon
threads are cleaned up during interpreter shutdown.

..

.. date: 2026-01-19-02-33-45
.. gh-issue: 144012
.. nonce: wVEEWs
.. section: Core and Builtins

Check if the result is ``NULL`` in ``BINARY_OP_EXTENT`` opcode.

..

.. date: 2026-01-19-01-56-44
.. gh-issue: 144007
.. nonce: 1xjdBf
.. section: Core and Builtins

Eliminate redundant refcounting in the JIT for ``BINARY_OP``.

..

.. date: 2026-01-19-01-26-12
.. gh-issue: 144005
.. nonce: Z3O33m
.. section: Core and Builtins

Eliminate redundant refcounting from ``BINARY_OP_EXTEND``.

..

.. date: 2026-01-16-23-19-38
.. gh-issue: 143939
.. nonce: w9TWch
.. section: Core and Builtins

Fix erroneous "cannot reuse already awaited coroutine" error that could
occur when a generator was run during the process of clearing a coroutine's
frame.

..

.. date: 2026-01-13-22-26-49
.. gh-issue: 141805
.. nonce: QzIKPS
.. section: Core and Builtins

Fix crash in :class:`set` when objects with the same hash are concurrently
added to the set after removing an element with the same hash while the set
still contains elements with the same hash.

..

.. date: 2026-01-11-20-11-36
.. gh-issue: 143670
.. nonce: klnGoD
.. section: Core and Builtins

Fixes a crash in ``ga_repr_items_list`` function.

..

.. date: 2026-01-10-10-58-36
.. gh-issue: 143650
.. nonce: k8mR4x
.. section: Core and Builtins

Fix race condition in :mod:`importlib` where a thread could receive a stale
module reference when another thread's import fails.

..

.. date: 2026-01-08-14-55-31
.. gh-issue: 143569
.. nonce: -Ltu3c
.. section: Core and Builtins

Generator expressions in 3.15 now conform to the documented behavior when
the iterable does not support iteration. This matches the behavior in 3.14
and earlier

..

.. date: 2025-12-29-19-31-46
.. gh-issue: 143192
.. nonce: JxGAyl
.. section: Core and Builtins

Improve performance of bitwise operations on multi-digit ints.

..

.. date: 2025-12-24-13-19-16
.. gh-issue: 132657
.. nonce: _P4DDb
.. section: Core and Builtins

If we are specializing to ``LOAD_GLOBAL_MODULE`` or ``LOAD_ATTR_MODULE``,
try to enable deferred reference counting for the value, if the object is
owned by a different thread.  This applies to the free-threaded build only
and should improve scaling of multi-threaded programs. Note that when
deferred reference counting is enabled, the object will be deallocated by
the GC, rather than by :c:func:`Py_DECREF`.

..

.. date: 2025-12-21-18-12-30
.. gh-issue: 143055
.. nonce: PzwccL
.. section: Core and Builtins

Implement :pep:`798` (Unpacking in Comprehensions).  Patch by Adam Hartz.

..

.. date: 2025-11-29-10-06-06
.. gh-issue: 142037
.. nonce: OpIGzK
.. section: Core and Builtins

Improve error messages for printf-style formatting. For errors in the format
string, always include the position of the start of the format unit. For
errors related to the formatted arguments, always include the number or the
name of the argument. Raise more specific errors and include more
information (type and number of arguments, most probable causes of error).

..

.. date: 2025-10-24-17-30-51
.. gh-issue: 140557
.. nonce: X2GETk
.. section: Core and Builtins

:class:`bytearray` buffers now have the same alignment when empty as when
allocated. Unaligned buffers can still be created by slicing.

..

.. date: 2025-10-16-22-36-05
.. gh-issue: 140232
.. nonce: u3srgv
.. section: Core and Builtins

Frozenset objects with immutable elements are no longer tracked by the
garbage collector.

..

.. date: 2024-02-10-05-42-26
.. gh-issue: 115231
.. nonce: 6T7dzi
.. section: Core and Builtins

Setup ``__module__`` attribute for built-in static methods.  Patch by Sergey
B Kirpichev.

..

.. date: 2026-01-16-15-04-26
.. gh-issue: 143869
.. nonce: vf94km
.. section: C API

Added :c:func:`PyLong_GetNativeLayout`, :c:struct:`PyLongLayout`,
:c:struct:`PyLongExport`, :c:func:`PyLong_Export`,
:c:func:`PyLong_FreeExport`, :c:struct:`PyLongWriter`,
:c:func:`PyLongWriter_Create`, :c:func:`PyLongWriter_Finish` and
:c:func:`PyLongWriter_Discard` to the limited API.

..

.. date: 2025-12-16-18-39-30
.. gh-issue: 141070
.. nonce: 4EKDZ1
.. section: C API

Renamed :c:func:`!PyUnstable_Object_Dump` to :c:func:`PyObject_Dump`.

..

.. date: 2026-02-10-06-31-29
.. gh-issue: 140421
.. nonce: vxosUx
.. section: Build

Disable the perf trampoline on older macOS versions where it cannot be
built.

..

.. date: 2026-01-28-19-04-12
.. gh-issue: 144309
.. nonce: 3sMFOh
.. section: Build

Build Python with POSIX 2024, instead of POSIX 2008. Patch by Victor
Stinner.

..

.. date: 2026-01-27-23-39-26
.. gh-issue: 144278
.. nonce: tejFwL
.. section: Build

Enables defining the ``_PY_IMPL_NAME`` and ``_PY_IMPL_CACHE_TAG``
preprocessor definitions to override :data:`sys.implementation` at build
time. Definitions need to include quotes when setting to a string literal.
Setting the cache tag to ``NULL`` has the effect of completely disabling
automatic creation and use of ``.pyc`` files.

..

.. date: 2026-01-17-15-31-19
.. gh-issue: 143960
.. nonce: Zi0EqR
.. section: Build

Add support for OpenSSL 3.6, drop EOL 3.2. Patch by Hugo van Kemenade.

..

.. date: 2026-01-16-14-27-53
.. gh-issue: 143941
.. nonce: TiaE-3
.. section: Build

Move WASI-related files to :file:`Platforms/WASI`. Along the way, leave a
deprecated :file:`Tools/wasm/wasi/__main__.py` behind for
backwards-compatibility.

..

.. date: 2026-01-15-03-36-16
.. gh-issue: 143842
.. nonce: EZLutl
.. section: Build

Prevent static builds from clashing with curses by making the optimizer
COLORS table static.