cpython/Misc/NEWS.d/3.12.0a5.rst

.. date: 2022-11-08-12-06-52
.. gh-issue: 99108
.. nonce: 4Wrsuh
.. release date: 2023-02-07
.. section: Security

Replace the builtin :mod:`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.

..

.. date: 2023-02-06-20-13-36
.. gh-issue: 92173
.. nonce: RQE0mk
.. section: Core and Builtins

Fix the ``defs`` and ``kwdefs`` arguments to :c:func:`PyEval_EvalCodeEx` and
a reference leak in that function.

..

.. date: 2023-01-30-11-56-09
.. gh-issue: 59956
.. nonce: 7xqnC_
.. section: Core and Builtins

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.

..

.. date: 2023-01-30-08-59-47
.. gh-issue: 101400
.. nonce: Di_ZFm
.. section: Core and Builtins

Fix wrong lineno in exception message on :keyword:`continue` or
:keyword:`break` which are not in a loop. Patch by Donghee Na.

..

.. date: 2023-01-28-20-31-42
.. gh-issue: 101372
.. nonce: 8BcpCC
.. section: Core and Builtins

Fix :func:`~unicodedata.is_normalized` to properly handle the UCD 3.2.0
cases. Patch by Donghee Na.

..

.. date: 2023-01-28-13-11-52
.. gh-issue: 101266
.. nonce: AxV3OF
.. section: Core and Builtins

Fix :func:`sys.getsizeof` reporting for :class:`int` subclasses.

..

.. date: 2023-01-24-17-13-32
.. gh-issue: 101291
.. nonce: Yr6u_c
.. section: Core and Builtins

Refactor the ``PyLongObject`` struct into a normal Python object header and
a ``PyLongValue`` struct.

..

.. date: 2023-01-15-03-26-04
.. gh-issue: 101046
.. nonce: g2CM4S
.. section: Core and Builtins

Fix a possible memory leak in the parser when raising :exc:`MemoryError`.
Patch by Pablo Galindo

..

.. date: 2023-01-14-17-03-08
.. gh-issue: 101037
.. nonce: 9ATNuf
.. section: Core and Builtins

Fix potential memory underallocation issue for instances of :class:`int`
subclasses with value zero.

..

.. date: 2023-01-13-12-56-20
.. gh-issue: 100762
.. nonce: YvHaQJ
.. section: Core and Builtins

Record the (virtual) exception block depth in the oparg of
:opcode:`YIELD_VALUE`. Use this to avoid the expensive ``throw()`` when
closing generators (and coroutines) that can be closed trivially.

..

.. date: 2023-01-12-13-46-49
.. gh-issue: 100982
.. nonce: mJ234s
.. section: Core and Builtins

Adds a new :opcode:`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.

..

.. date: 2023-01-11-22-52-19
.. gh-issue: 100942
.. nonce: ontOy_
.. section: Core and Builtins

Fixed segfault in property.getter/setter/deleter that occurred when a
property subclass overrode the ``__new__`` method to return a non-property
instance.

..

.. date: 2023-01-10-16-59-33
.. gh-issue: 100923
.. nonce: ypJAX-
.. section: Core and Builtins

Remove the ``mask`` cache entry for the :opcode:`COMPARE_OP` instruction and
embed the mask into the oparg.

..

.. date: 2023-01-10-14-11-17
.. gh-issue: 100892
.. nonce: qfBVYI
.. section: Core and Builtins

Fix race while iterating over thread states in clearing
:class:`threading.local`. Patch by Kumar Aditya.

..

.. date: 2023-01-06-09-22-21
.. gh-issue: 91351
.. nonce: iq2vZ_
.. section: Core and Builtins

Fix a case where re-entrant imports could corrupt the import deadlock
detection code and cause a :exc:`KeyError` to be raised out of
:mod:`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)

..

.. date: 2023-01-03-20-59-20
.. gh-issue: 100726
.. nonce: W9huFl
.. section: Core and Builtins

Optimize construction of ``range`` object for medium size integers.

..

.. date: 2023-01-03-14-33-23
.. gh-issue: 100712
.. nonce: po6xyB
.. section: Core and Builtins

Added option to build cpython with specialization disabled, by setting
``ENABLE_SPECIALIZATION=False`` in :mod:`opcode`, followed by ``make
regen-all``.

..

.. bpo: 32780
.. date: 2018-02-05-21-54-46
.. nonce: Dtiz8z
.. section: Core and Builtins

Inter-field padding is now inserted into the PEP3118 format strings obtained
from :class:`ctypes.Structure` objects, reflecting their true representation
in memory.

..

.. date: 2023-02-05-14-39-49
.. gh-issue: 101541
.. nonce: Mo3ppp
.. section: Library

[Enum] - fix psuedo-flag creation

..

.. date: 2023-02-04-21-01-49
.. gh-issue: 101570
.. nonce: lbtUsD
.. section: Library

Upgrade pip wheel bundled with ensurepip (pip 23.0)

..

.. date: 2023-01-26-06-44-35
.. gh-issue: 101323
.. nonce: h8Hk11
.. section: Library

Fix a bug where errors where not thrown by zlib._ZlibDecompressor if
encountered during decompressing.

..

.. date: 2023-01-26-01-25-56
.. gh-issue: 101317
.. nonce: vWaS1x
.. section: Library

Add *ssl_shutdown_timeout* parameter for
:meth:`asyncio.StreamWriter.start_tls`.

..

.. date: 2023-01-25-18-07-20
.. gh-issue: 101326
.. nonce: KL4SFv
.. section: Library

Fix regression when passing ``None`` as second or third argument to
``FutureIter.throw``.

..

.. date: 2023-01-24-12-53-59
.. gh-issue: 92123
.. nonce: jf6TO5
.. section: Library

Adapt the ``_elementtree`` extension module to multi-phase init
(:pep:`489`). Patches by Erlend E. Aasland.

..

.. date: 2023-01-21-16-50-22
.. gh-issue: 100795
.. nonce: NPMZf7
.. section: Library

Avoid potential unexpected ``freeaddrinfo`` call (double free) in
:mod:`socket` when when a libc ``getaddrinfo()`` implementation leaves
garbage in an output pointer when returning an error. Original patch by
Sergey G. Brester.

..

.. date: 2023-01-20-10-46-59
.. gh-issue: 101143
.. nonce: hJo8hu
.. section: Library

Remove unused references to :class:`~asyncio.TimerHandle` in
``asyncio.base_events.BaseEventLoop._add_callback``.

..

.. date: 2023-01-18-17-58-50
.. gh-issue: 101144
.. nonce: FHd8Un
.. section: Library

Make :func:`zipfile.Path.open` and :func:`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 :exc:`TypeError`.

..

.. date: 2023-01-15-09-11-30
.. gh-issue: 94518
.. nonce: jvxtxm
.. section: Library

Group-related variables of ``_posixsubprocess`` module are renamed to stress
that supplimentary group affinity is added to a fork, not replace the
inherited ones. Patch by Oleg Iarygin.

..

.. date: 2023-01-14-12-58-21
.. gh-issue: 101015
.. nonce: stWFid
.. section: Library

Fix :func:`typing.get_type_hints` on ``'*tuple[...]'`` and ``*tuple[...]``.
It must not drop the ``Unpack`` part.

..

.. date: 2023-01-12-21-22-20
.. gh-issue: 101000
.. nonce: wz4Xgc
.. section: Library

Add :func:`os.path.splitroot()`, which splits a path into a 3-item tuple
``(drive, root, tail)``. This new function is used by :mod:`pathlib` to
improve the performance of path construction by up to a third.

..

.. date: 2023-01-12-01-18-13
.. gh-issue: 100573
.. nonce: KDskqo
.. section: Library

Fix a Windows :mod:`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.

..

.. date: 2023-01-08-00-12-44
.. gh-issue: 39615
.. nonce: gn4PhB
.. section: Library

:func:`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.

..

.. date: 2023-01-04-14-42-59
.. gh-issue: 100750
.. nonce: iFJs5Y
.. section: Library

pass encoding kwarg to subprocess in platform

..

.. date: 2022-12-21-17-49-50
.. gh-issue: 100160
.. nonce: N0NHRj
.. section: Library

Emit a deprecation warning in
:meth:`asyncio.DefaultEventLoopPolicy.get_event_loop` if there is no current
event loop set and it decides to create one.

..

.. date: 2022-12-19-23-19-26
.. gh-issue: 96290
.. nonce: qFjsi6
.. section: Library

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.

..

.. date: 2022-12-11-14-38-59
.. gh-issue: 99952
.. nonce: IYGLzr
.. section: Library

Fix a reference undercounting issue in :class:`ctypes.Structure` with
``from_param()`` results larger than a C pointer.

..

.. date: 2022-12-10-15-30-17
.. gh-issue: 67790
.. nonce: P9YUZM
.. section: Library

Add float-style formatting support for :class:`fractions.Fraction`
instances.

..

.. date: 2022-11-24-21-52-31
.. gh-issue: 99266
.. nonce: 88GcV9
.. section: Library

Preserve more detailed error messages in :mod:`ctypes`.

..

.. date: 2022-11-15-23-30-39
.. gh-issue: 86682
.. nonce: gK9i1N
.. section: Library

Ensure runtime-created collections have the correct module name using the
newly added (internal) :func:`sys._getframemodulename`.

..

.. date: 2022-11-14-03-06-03
.. gh-issue: 88597
.. nonce: EYJA-Q
.. section: Library

:mod:`uuid` now has a command line interface. Try ``python -m uuid -h``.

..

.. date: 2022-09-26-21-18-47
.. gh-issue: 60580
.. nonce: 0hBgde
.. section: Library

:data:`ctypes.wintypes.BYTE` definition changed from :data:`~ctypes.c_byte`
to :data:`~ctypes.c_ubyte` to match Windows SDK. Patch by Anatoly Techtonik
and Oleg Iarygin.

..

.. date: 2022-07-22-13-38-37
.. gh-issue: 94518
.. nonce: _ZP0cz
.. section: Library

``_posixsubprocess`` now initializes all UID and GID variables using a
reserved ``-1`` value instead of a separate flag. Patch by Oleg Iarygin.

..

.. bpo: 38941
.. date: 2022-02-05-12-01-58
.. nonce: 8IhvyG
.. section: Library

The :mod:`xml.etree.ElementTree` module now emits :exc:`DeprecationWarning`
when testing the truth value of an :class:`xml.etree.ElementTree.Element`.
Before, the Python implementation emitted :exc:`FutureWarning`, and the C
implementation emitted nothing.

..

.. bpo: 40077
.. date: 2020-11-20-21-06-08
.. nonce: M-iZq3
.. section: Library

Convert :mod:`elementtree` types to heap types. Patch by Erlend E. Aasland.

..

.. bpo: 29847
.. date: 2020-04-18-17-45-03
.. nonce: Uxtbq0
.. section: Library

Fix a bug where :class:`pathlib.Path` accepted and ignored keyword
arguments. Patch provided by Yurii Karabas.

..

.. date: 2018-05-21-17-18-00
.. gh-issue: 77772
.. nonce: Fhg84L
.. section: Library

:class:`ctypes.CDLL`, :class:`ctypes.OleDLL`, :class:`ctypes.WinDLL`, and
:class:`ctypes.PyDLL` now accept :term:`path-like objects <path-like
object>` as their ``name`` argument. Patch by Robert Hoelzl.

..

.. date: 2022-06-19-22-04-47
.. gh-issue: 88324
.. nonce: GHhSQ1
.. section: Documentation

Reword :mod:`subprocess` to emphasize default behavior of *stdin*, *stdout*,
and *stderr* arguments. Remove inaccurate statement about child file handle
inheritance.

..

.. date: 2023-02-04-17-24-33
.. gh-issue: 101334
.. nonce: _yOqwg
.. section: Tests

``test_tarfile`` has been updated to pass when run as a high UID.

..

.. date: 2023-02-04-06-59-07
.. gh-issue: 101282
.. nonce: 7sQz5l
.. section: Build

Update BOLT configration not to use depreacted usage of ``--split
functions``. Patch by Donghee Na.

..

.. date: 2023-02-02-23-43-46
.. gh-issue: 101522
.. nonce: lnUDta
.. section: Build

Allow overriding Windows dependencies versions and paths using MSBuild
properties.

..

.. date: 2023-01-26-19-02-11
.. gh-issue: 77532
.. nonce: cXD8bg
.. section: Build

Minor fixes to allow building with ``PlatformToolset=ClangCL`` on Windows.

..

.. date: 2023-01-21-10-31-35
.. gh-issue: 101152
.. nonce: xvM8pL
.. section: Build

In accordance with :PEP:`699`, the ``ma_version_tag`` field in
:c:type:`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.

..

.. date: 2023-01-17-21-32-51
.. gh-issue: 100340
.. nonce: i9zRGM
.. section: Build

Allows -Wno-int-conversion for wasm-sdk 17 and onwards, thus enables
building WASI builds once against the latest sdk.

..

.. date: 2023-01-15-11-22-15
.. gh-issue: 101060
.. nonce: 0mYk9E
.. section: Build

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.

..

.. date: 2022-10-27-09-57-12
.. gh-issue: 98705
.. nonce: H11XmR
.. section: Build

``__bool__`` is defined in AIX system header files which breaks the build in
AIX, so undefine it.

..

.. date: 2022-10-25-11-53-55
.. gh-issue: 98636
.. nonce: e0RPAr
.. section: Build

Fix a regression in detecting ``gdbm_compat`` library for the ``_gdbm``
module build.

..

.. date: 2022-08-30-10-16-31
.. gh-issue: 96305
.. nonce: 274i8B
.. section: Build

``_aix_support`` now uses a simple code to get platform details rather than
the now non-existent ``_bootsubprocess`` during bootstrap.

..

.. date: 2023-02-03-17-53-06
.. gh-issue: 101543
.. nonce: cORAT4
.. section: Windows

Ensure the install path in the registry is only used when the standard
library hasn't been located in any other way.

..

.. date: 2023-01-31-16-50-07
.. gh-issue: 101467
.. nonce: ye9t-L
.. section: Windows

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``.

..

.. date: 2023-01-25-00-23-31
.. gh-issue: 99834
.. nonce: WN41lc
.. section: Windows

Updates bundled copy of Tcl/Tk to 8.6.13.0

..

.. date: 2023-01-18-18-25-18
.. gh-issue: 101135
.. nonce: HF9VlG
.. section: Windows

Restore ability to launch older 32-bit versions from the :file:`py.exe`
launcher when both 32-bit and 64-bit installs of the same version are
available.

..

.. date: 2023-01-17-18-17-58
.. gh-issue: 82052
.. nonce: mWyysT
.. section: Windows

Fixed an issue where writing more than 32K of Unicode output to the console
screen in one go can result in mojibake.

..

.. date: 2023-01-11-16-28-09
.. gh-issue: 100320
.. nonce: 2DU2it
.. section: Windows

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.

..

.. date: 2023-01-11-14-42-11
.. gh-issue: 100247
.. nonce: YfEmSz
.. section: Windows

Restores support for the :file:`py.exe` launcher finding shebang commands in
its configuration file using the full command name.