cpython/Misc/NEWS.d/3.12.0a6.rst

.. date: 2023-02-17-10-42-48
.. gh-issue: 99108
.. nonce: MKA8-f
.. release date: 2023-03-07
.. section: Security

Replace builtin hashlib implementations of MD5 and SHA1 with verified ones
from the HACL* project.

..

.. date: 2023-02-08-22-03-04
.. gh-issue: 101727
.. nonce: 9P5eZz
.. section: Security

Updated the OpenSSL version used in Windows and macOS binary release builds
to 1.1.1t to address CVE-2023-0286, CVE-2022-4303, and CVE-2022-4303 per
`the OpenSSL 2023-02-07 security advisory
<https://www.openssl.org/news/secadv/20230207.txt>`_.

..

.. date: 2023-02-08-12-57-35
.. gh-issue: 99108
.. nonce: 6tnmhA
.. section: Security

Replace the builtin :mod:`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.

..

.. date: 2023-01-24-16-12-00
.. gh-issue: 101283
.. nonce: 9tqu39
.. section: Security

:class:`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.

..

.. date: 2023-03-07-16-56-28
.. gh-issue: 102493
.. nonce: gTXrcD
.. section: Core and Builtins

Fix regression in semantics of normalisation in ``PyErr_SetObject``.

..

.. date: 2023-03-06-13-05-33
.. gh-issue: 102416
.. nonce: dz6K5f
.. section: Core and Builtins

Do not memoize incorrectly automatically generated loop rules in the parser.
Patch by Pablo Galindo.

..

.. date: 2023-03-04-20-56-12
.. gh-issue: 102356
.. nonce: 07KvUd
.. section: Core and Builtins

Fix a bug that caused a crash when deallocating deeply nested filter
objects. Patch by Marta Gómez Macías.

..

.. date: 2023-02-28-21-17-03
.. gh-issue: 102336
.. nonce: -wL3Tm
.. section: Core and Builtins

Cleanup Windows 7 specific special handling. Patch by Max Bachmann.

..

.. date: 2023-02-26-23-10-32
.. gh-issue: 102250
.. nonce: 7MUKoC
.. section: Core and Builtins

Fixed a segfault occurring when the interpreter calls a ``__bool__`` method
that raises.

..

.. date: 2023-02-24-17-59-39
.. gh-issue: 102126
.. nonce: HTT8Vc
.. section: Core and Builtins

Fix deadlock at shutdown when clearing thread states if any finalizer tries
to acquire the runtime head lock. Patch by Kumar Aditya.

..

.. date: 2023-02-22-15-15-32
.. gh-issue: 102027
.. nonce: Km4G-d
.. section: Core and Builtins

Use ``GetCurrentProcessId`` on Windows when ``getpid`` is unavailable. Patch
by Max Bachmann.

..

.. date: 2023-02-20-15-18-33
.. gh-issue: 102056
.. nonce: uHKuwH
.. section: Core and Builtins

Fix error handling bugs in interpreter's exception printing code, which
could cause a crash on infinite recursion.

..

.. date: 2023-02-17-10-12-13
.. gh-issue: 100982
.. nonce: mJGJQw
.. section: Core and Builtins

Restrict the scope of the :opcode:`FOR_ITER_RANGE` instruction to the scope
of the original :opcode:`FOR_ITER` instruction, to allow instrumentation.

..

.. date: 2023-02-16-23-19-01
.. gh-issue: 101967
.. nonce: Kqr1dz
.. section: Core and Builtins

Fix possible segfault in ``positional_only_passed_as_keyword`` function,
when new list created.

..

.. date: 2023-02-16-16-57-23
.. gh-issue: 101952
.. nonce: Zo1dlq
.. section: Core and Builtins

Fix possible segfault in ``BUILD_SET`` opcode, when new set created.

..

.. date: 2023-02-13-22-21-58
.. gh-issue: 74895
.. nonce: esMNtq
.. section: Core and Builtins

:mod:`socket.getaddrinfo` no longer raises :class:`OverflowError` for
:class:`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
:class:`socket.gaierror` ``SAI_SERVICE`` may occur instead, or no error at
all as not all platform C libraries generate an error.

..

.. date: 2023-02-13-18-21-14
.. gh-issue: 101799
.. nonce: wpHbCn
.. section: Core and Builtins

Add :opcode:`CALL_INTRINSIC_2` and use it instead of
:opcode:`PREP_RERAISE_STAR`.

..

.. date: 2023-02-12-22-40-22
.. gh-issue: 101857
.. nonce: _bribG
.. section: Core and Builtins

Fix xattr support detection on Linux systems by widening the check to linux,
not just glibc. This fixes support for musl.

..

.. date: 2023-02-11-23-14-06
.. gh-issue: 84783
.. nonce: _P5sMa
.. section: Core and Builtins

Make the slice object hashable. Patch by Will Bradshaw and Furkan Onder.

..

.. date: 2023-02-10-15-54-57
.. gh-issue: 87849
.. nonce: IUVvPz
.. section: Core and Builtins

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.

..

.. date: 2023-02-10-07-21-47
.. gh-issue: 101765
.. nonce: MO5LlC
.. section: Core and Builtins

Fix SystemError / segmentation fault in iter ``__reduce__`` when internal
access of ``builtins.__dict__`` keys mutates the iter object.

..

.. date: 2023-02-10-01-15-57
.. gh-issue: 101430
.. nonce: T3Gegb
.. section: Core and Builtins

Update :mod:`tracemalloc` to handle presize of object properly. Patch by
Dong-hee Na.

..

.. date: 2023-02-08-17-13-31
.. gh-issue: 101696
.. nonce: seJhTt
.. section: Core and Builtins

Invalidate type version tag in ``_PyStaticType_Dealloc`` for static types,
avoiding bug where a false cache hit could crash the interpreter. Patch by
Kumar Aditya.

..

.. date: 2023-02-07-14-56-43
.. gh-issue: 101632
.. nonce: Fd1yxk
.. section: Core and Builtins

Adds a new :opcode:`RETURN_CONST` instruction.

..

.. date: 2023-01-04-12-49-33
.. gh-issue: 100719
.. nonce: uRPccL
.. section: Core and Builtins

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.

..

.. date: 2022-11-02-20-23-47
.. gh-issue: 98627
.. nonce: VJkdRM
.. section: Core and Builtins

When an interpreter is configured to check (and only then), importing an
extension module will now fail when the extension does not support multiple
interpreters (i.e. doesn't implement PEP 489 multi-phase init). This does
not apply to the main interpreter, nor to subinterpreters created with
``Py_NewInterpreter()``.

..

.. date: 2023-03-04-14-46-47
.. gh-issue: 102302
.. nonce: -b_s6Z
.. section: Library

Micro-optimise hashing of :class:`inspect.Parameter`, reducing the time it
takes to hash an instance by around 40%.

..

.. date: 2023-02-28-09-52-25
.. gh-issue: 101979
.. nonce: or3hXV
.. section: Library

Fix a bug where parentheses in the ``metavar`` argument to
:meth:`argparse.ArgumentParser.add_argument` were dropped. Patch by Yeojin
Kim.

..

.. date: 2023-02-26-12-37-17
.. gh-issue: 91038
.. nonce: S4rFH_
.. section: Library

:meth:`platform.platform` now has boolean default arguments.

..

.. date: 2023-02-23-20-39-52
.. gh-issue: 81652
.. nonce: Vxz0Mr
.. section: Library

Add :const:`mmap.MAP_ALIGNED_SUPER` FreeBSD and :const:`mmap.MAP_CONCEAL`
OpenBSD constants to :mod:`mmap`. Patch by Yeojin Kim.

..

.. date: 2023-02-23-15-06-01
.. gh-issue: 102179
.. nonce: P6KQ4c
.. section: Library

Fix :func:`os.dup2` error message for negative fds.

..

.. date: 2023-02-21-10-05-33
.. gh-issue: 101961
.. nonce: 7e56jh
.. section: Library

For the binary mode, :func:`fileinput.hookcompressed` doesn't set the
``encoding`` value even if the value is ``None``. Patch by Gihwan Kim.

..

.. date: 2023-02-21-07-15-41
.. gh-issue: 101936
.. nonce: QVOxHH
.. section: Library

The default value of ``fp`` becomes :class:`io.BytesIO` if
:exc:`~urllib.error.HTTPError` is initialized without a designated ``fp``
parameter. Patch by Long Vo.

..

.. date: 2023-02-17-20-24-15
.. gh-issue: 101566
.. nonce: FjgWBt
.. section: Library

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``.

..

.. date: 2023-02-17-19-00-58
.. gh-issue: 97930
.. nonce: C_nQjb
.. section: Library

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).

..

.. date: 2023-02-17-18-44-27
.. gh-issue: 101997
.. nonce: A6_blD
.. section: Library

Upgrade pip wheel bundled with ensurepip (pip 23.0.1)

..

.. date: 2023-02-15-01-54-06
.. gh-issue: 99108
.. nonce: rjTSic
.. section: Library

The built-in extension modules for :mod:`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.

..

.. date: 2023-02-14-09-08-48
.. gh-issue: 101892
.. nonce: FMos8l
.. section: Library

Callable iterators no longer raise :class:`SystemError` when the callable
object exhausts the iterator but forgets to either return a sentinel value
or raise :class:`StopIteration`.

..

.. date: 2023-02-13-12-55-48
.. gh-issue: 87634
.. nonce: q-SBhJ
.. section: Library

Remove locking behavior from :func:`functools.cached_property`.

..

.. date: 2023-02-11-13-23-29
.. gh-issue: 97786
.. nonce: QjvQ1B
.. section: Library

Fix potential undefined behaviour in corner cases of floating-point-to-time
conversions.

..

.. date: 2023-02-10-16-02-29
.. gh-issue: 101517
.. nonce: r7S2u8
.. section: Library

Fixed bug where :mod:`bdb` looks up the source line with :mod:`linecache`
with a ``lineno=None``, which causes it to fail with an unhandled exception.

..

.. date: 2023-02-10-11-59-13
.. gh-issue: 101773
.. nonce: J_kI7y
.. section: Library

Optimize :class:`fractions.Fraction` for small components. The private
argument ``_normalize`` of the :class:`fractions.Fraction` constructor has
been removed.

..

.. date: 2023-02-08-18-20-58
.. gh-issue: 101693
.. nonce: 4_LPXj
.. section: Library

In :meth:`sqlite3.Cursor.execute`, :exc:`DeprecationWarning` is now emitted
when :ref:`named placeholders <sqlite3-placeholders>` are used together with
parameters supplied as a :term:`sequence` instead of as a :class:`dict`.
Starting from Python 3.14, using named placeholders with parameters supplied
as a sequence will raise a :exc:`~sqlite3.ProgrammingError`. Patch by Erlend
E. Aasland.

..

.. date: 2023-02-07-22-21-46
.. gh-issue: 101446
.. nonce: -c0FdK
.. section: Library

Change repr of :class:`collections.OrderedDict` to use regular dictionary
formating instead of pairs of keys and values.

..

.. date: 2023-02-07-22-20-32
.. gh-issue: 101362
.. nonce: Jlk6mt
.. section: Library

Speed up :class:`pathlib.PurePath` construction by handling arguments more
uniformly. When a :class:`pathlib.Path` argument is supplied, we use its
string representation rather than joining its parts with
:func:`os.path.join`.

..

.. date: 2023-02-07-21-16-41
.. gh-issue: 101362
.. nonce: KMQllM
.. section: Library

Speed up :class:`pathlib.PurePath` construction by calling
:func:`os.path.join` only when two or more arguments are given.

..

.. date: 2023-02-07-20-46-08
.. gh-issue: 101362
.. nonce: 2ckZ6R
.. section: Library

Speed up :class:`pathlib.Path` construction by running the path flavour
compatibility check only when pathlib is imported.

..

.. date: 2023-02-05-21-40-15
.. gh-issue: 85984
.. nonce: Kfzbb2
.. section: Library

Refactored the implementation of :func:`pty.fork` to use
:func:`os.login_tty`.

A :exc:`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 :func:`pty.openpty`.

..

.. date: 2023-02-04-16-35-46
.. gh-issue: 101561
.. nonce: Xo6pIZ
.. section: Library

Add a new decorator :func:`typing.override`. See :pep:`698` for details.
Patch by Steven Troxler.

..

.. date: 2023-02-01-10-42-16
.. gh-issue: 63301
.. nonce: XNxSFh
.. section: Library

Set exit code when :mod:`tabnanny` CLI exits on error.

..

.. date: 2023-01-27-02-53-50
.. gh-issue: 101360
.. nonce: bPB7SL
.. section: Library

Fix anchor matching in :meth:`pathlib.PureWindowsPath.match`. Path and
pattern anchors are now matched with :mod:`fnmatch`, just like other path
parts. This allows patterns such as ``"*:/Users/*"`` to be matched.

..

.. date: 2023-01-25-00-14-52
.. gh-issue: 101277
.. nonce: FceHX7
.. section: Library

Remove global state from :mod:`itertools` module (:pep:`687`). Patches by
Erlend E. Aasland.

..

.. date: 2023-01-06-21-14-41
.. gh-issue: 100809
.. nonce: I697UT
.. section: Library

Fix handling of drive-relative paths (like 'C:' and 'C:foo') in
:meth:`pathlib.Path.absolute`. This method now uses the OS API to retrieve
the correct current working directory for the drive.

..

.. date: 2023-01-02-22-41-44
.. gh-issue: 99138
.. nonce: 17hp9U
.. section: Library

Apply :pep:`687` to :mod:`zoneinfo`. Patch by Erlend E. Aasland.

..

.. date: 2022-10-22-09-26-43
.. gh-issue: 96764
.. nonce: Dh9Y5L
.. section: Library

:func:`asyncio.wait_for` now uses :func:`asyncio.timeout` as its underlying
implementation. Patch by Kumar Aditya.

..

.. date: 2022-09-05-12-17-34
.. gh-issue: 88233
.. nonce: gff9qJ
.. section: Library

Correctly preserve "extra" fields in ``zipfile`` regardless of their
ordering relative to a zip64 "extra."

..

.. bpo: 23224
.. date: 2018-06-20-09-12-21
.. nonce: zxCQ13
.. section: Library

Fix segfaults when creating :class:`lzma.LZMADecompressor` and
:class:`bz2.BZ2Decompressor` objects without calling ``__init__()``, and fix
leakage of locks and internal buffers when calling the ``__init__()``
methods of :class:`lzma.LZMADecompressor`, :class:`lzma.LZMACompressor`,
:class:`bz2.BZ2Compressor`, and :class:`bz2.BZ2Decompressor` objects
multiple times.

..

.. date: 2023-02-19-10-33-01
.. gh-issue: 85417
.. nonce: kYO8u3
.. section: Documentation

Update :mod:`cmath` documentation to clarify behaviour on branch cuts.

..

.. date: 2023-02-07-21-43-24
.. gh-issue: 97725
.. nonce: cuY7Cd
.. section: Documentation

Fix :meth:`asyncio.Task.print_stack` description for ``file=None``. Patch by
Oleg Iarygin.

..

.. date: 2023-02-18-10-51-02
.. gh-issue: 102019
.. nonce: 0797SJ
.. section: Tests

Fix deadlock on shutdown if ``test_current_{exception,frames}`` fails. Patch
by Jacob Bower.

..

.. date: 2023-02-11-22-36-10
.. gh-issue: 85984
.. nonce: EVXjT9
.. section: Tests

Utilize new "winsize" functions from termios in pty tests.

..

.. date: 2023-02-11-20-28-08
.. gh-issue: 89792
.. nonce: S-Y5BZ
.. section: Tests

``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.

..

.. date: 2023-01-12-00-49-16
.. gh-issue: 99942
.. nonce: DUR8b4
.. section: Build

On Android, in a static build, python-config in embed mode no longer
incorrectly reports a library to link to.

..

.. date: 2022-12-20-01-06-17
.. gh-issue: 99942
.. nonce: lbmzYj
.. section: Build

On Android, python.pc now correctly reports the library to link to, the same
as python-config.sh.

..

.. date: 2022-12-18-08-33-28
.. gh-issue: 100221
.. nonce: K94Ct3
.. section: Build

Fix creating install directories in ``make sharedinstall`` if they exist
outside ``DESTDIR`` already.

..

.. date: 2022-09-14-10-38-15
.. gh-issue: 96821
.. nonce: Zk2a9c
.. section: Build

Explicitly mark C extension modules that need defined signed integer
overflow, and add a configure option :option:`--with-strict-overflow`. Patch
by Matthias Görgens and Shantanu Jain.

..

.. date: 2023-03-01-01-36-39
.. gh-issue: 102344
.. nonce: Dgfux4
.. section: Windows

Implement ``winreg.QueryValue`` using ``QueryValueEx`` and
``winreg.SetValue`` using ``SetValueEx``. Patch by Max Bachmann.

..

.. date: 2023-02-15-11-08-10
.. gh-issue: 101881
.. nonce: fScr3m
.. section: Windows

Handle read and write operations on non-blocking pipes properly on Windows.

..

.. date: 2023-02-13-18-05-49
.. gh-issue: 101881
.. nonce: _TnHzN
.. section: Windows

Add support for the os.get_blocking() and os.set_blocking() functions on
Windows.

..

.. date: 2023-02-13-16-32-50
.. gh-issue: 101849
.. nonce: 7lm_53
.. section: Windows

Ensures installer will correctly upgrade existing ``py.exe`` launcher
installs.

..

.. date: 2023-02-10-14-26-05
.. gh-issue: 101763
.. nonce: RPaj7r
.. section: Windows

Updates copy of libffi bundled with Windows installs to 3.4.4.

..

.. date: 2023-02-09-22-09-27
.. gh-issue: 101759
.. nonce: zFlqSH
.. section: Windows

Update Windows installer to SQLite 3.40.1.

..

.. date: 2023-02-07-18-22-54
.. gh-issue: 101614
.. nonce: NjVP0n
.. section: Windows

Correctly handle extensions built against debug binaries that reference
``python3_d.dll``.

..

.. date: 2023-01-25-11-33-54
.. gh-issue: 101196
.. nonce: wAX_2g
.. section: Windows

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.

..

.. date: 2023-02-09-22-07-17
.. gh-issue: 101759
.. nonce: B0JP2H
.. section: macOS

Update macOS installer to SQLite 3.40.1.

..

.. date: 2023-02-14-15-53-01
.. gh-issue: 101907
.. nonce: HgF1N2
.. section: C API

Removes use of non-standard C++ extension in public header files.

..

.. date: 2023-02-09-10-38-20
.. gh-issue: 99293
.. nonce: mFqfpp
.. section: C API

Document that the Py_TPFLAGS_VALID_VERSION_TAG is an internal feature,
should not be used, and will be removed.

..

.. date: 2023-02-06-16-14-30
.. gh-issue: 101578
.. nonce: PW5fA9
.. section: C API

Add :c:func:`PyErr_GetRaisedException` and
:c:func:`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 :c:func:`PyErr_Fetch`
and :c:func:`PyErr_Restore`. This is less error prone and a bit more
efficient.

Add :c:func:`PyException_GetArgs` and :c:func:`PyException_SetArgs` as
convenience functions for retrieving and modifying the
:attr:`~BaseException.args` passed to the exception's constructor.

..

.. date: 2022-04-21-17-25-22
.. gh-issue: 91744
.. nonce: FgvaMi
.. section: C API

Introduced the *Unstable C API tier*, marking APi that is allowed to change
in minor releases without a deprecation period. See :pep:`689` for details.