.. bpo: 42268
.. date: 2021-11-26-22-31-22
.. nonce: 3wl-09
.. release date: 2021-12-06
.. section: Core and Builtins

Fail the configure step if the selected compiler doesn't support memory
sanitizer. Patch by Pablo Galindo

..

.. bpo: 45727
.. date: 2021-11-24-18-24-49
.. nonce: _xVbbo
.. section: Core and Builtins

Refine the custom syntax error that suggests that a comma may be missing to
trigger only when the expressions are detected between parentheses or
brackets. Patch by Pablo Galindo

..

.. bpo: 45614
.. date: 2021-11-23-12-06-41
.. nonce: fIekgI
.. section: Core and Builtins

Fix :mod:`traceback` display for exceptions with invalid module name.

..

.. bpo: 45848
.. date: 2021-11-19-22-57-42
.. nonce: HgVBJ5
.. section: Core and Builtins

Allow the parser to obtain error lines directly from encoded files. Patch by
Pablo Galindo

..

.. bpo: 45826
.. date: 2021-11-17-08-05-27
.. nonce: OERoTm
.. section: Core and Builtins

Fixed a crash when calling ``.with_traceback(None)`` on ``NameError``. This
occurs internally in ``unittest.TestCase.assertRaises()``.

..

.. bpo: 45822
.. date: 2021-11-16-19-41-04
.. nonce: OT6ueS
.. section: Core and Builtins

Fixed a bug in the parser that was causing it to not respect :pep:`263`
coding cookies when no flags are provided. Patch by Pablo Galindo

..

.. bpo: 45820
.. date: 2021-11-16-19-00-27
.. nonce: 2X6Psr
.. section: Core and Builtins

Fix a segfault when the parser fails without reading any input. Patch by
Pablo Galindo

..

.. bpo: 42540
.. date: 2021-11-15-12-08-27
.. nonce: V2w107
.. section: Core and Builtins

Fix crash when :func:`os.fork` is called with an active non-default memory
allocator.

..

.. bpo: 45738
.. date: 2021-11-14-00-14-45
.. nonce: e0cgKd
.. section: Core and Builtins

Fix computation of error location for invalid continuation characters in the
parser. Patch by Pablo Galindo.

..

.. bpo: 45773
.. date: 2021-11-09-13-01-35
.. nonce: POU8A4
.. section: Core and Builtins

Fix a compiler hang when attempting to optimize certain jump patterns.

..

.. bpo: 45716
.. date: 2021-11-04-20-19-07
.. nonce: 5C0pA1
.. section: Core and Builtins

Improve the :exc:`SyntaxError` message when using ``True``, ``None`` or
``False`` as keywords in a function call. Patch by Pablo Galindo.

..

.. bpo: 45688
.. date: 2021-11-02-09-27-46
.. nonce: v5Der1
.. section: Core and Builtins

:data:`sys.stdlib_module_names` now contains the macOS-specific module
:mod:`_scproxy`.

..

.. bpo: 30570
.. date: 2021-10-19-01-04-08
.. nonce: _G30Ms
.. section: Core and Builtins

Fixed a crash in ``issubclass()`` from infinite recursion when searching
pathological ``__bases__`` tuples.

..

.. bpo: 45521
.. date: 2021-10-18-22-40-33
.. nonce: GdMiuW
.. section: Core and Builtins

Fix a bug in the obmalloc radix tree code.  On 64-bit machines, the bug
causes the tree to hold 46-bits of virtual addresses, rather than the
intended 48-bits.

..

.. bpo: 45494
.. date: 2021-10-16-17-27-48
.. nonce: vMt1g4
.. section: Core and Builtins

Fix parser crash when reporting errors involving invalid continuation
characters. Patch by Pablo Galindo.

..

.. bpo: 45408
.. date: 2021-10-07-21-26-44
.. nonce: qUqzcd
.. section: Core and Builtins

Fix a crash in the parser when reporting tokenizer errors that occur at the
same time unclosed parentheses are detected. Patch by Pablo Galindo.

..

.. bpo: 45385
.. date: 2021-10-06-21-20-11
.. nonce: CTUT8s
.. section: Core and Builtins

Fix reference leak from descr_check. Patch by Dong-hee Na.

..

.. bpo: 45167
.. date: 2021-09-14-09-23-59
.. nonce: CPSSoV
.. section: Core and Builtins

Fix deepcopying of :class:`types.GenericAlias` objects.

..

.. bpo: 44219
.. date: 2021-09-09-10-32-33
.. nonce: WiYyjz
.. section: Core and Builtins

Release the GIL while performing ``isatty`` system calls on arbitrary file
descriptors. In particular, this affects :func:`os.isatty`,
:func:`os.device_encoding` and :class:`io.TextIOWrapper`. By extension,
:func:`io.open` in text mode is also affected. This change solves a deadlock
in :func:`os.isatty`. Patch by Vincent Michel in :issue:`44219`.

..

.. bpo: 44959
.. date: 2021-09-08-08-29-41
.. nonce: OSwwPf
.. section: Core and Builtins

Added fallback to extension modules with '.sl' suffix on HP-UX

..

.. bpo: 44050
.. date: 2021-09-08-00-30-09
.. nonce: mFI15u
.. section: Core and Builtins

Extensions that indicate they use global state (by setting ``m_size`` to -1)
can again be used in multiple interpreters. This reverts to behavior of
Python 3.8.

..

.. bpo: 45121
.. date: 2021-09-07-17-10-16
.. nonce: iG-Hsf
.. section: Core and Builtins

Fix issue where ``Protocol.__init__`` raises ``RecursionError`` when it's
called directly or via ``super()``. Patch provided by Yurii Karabas.

..

.. bpo: 45083
.. date: 2021-09-01-23-55-49
.. nonce: cLi9G3
.. section: Core and Builtins

When the interpreter renders an exception, its name now has a complete
qualname. Previously only the class name was concatenated to the module
name, which sometimes resulted in an incorrect full name being displayed.

(This issue impacted only the C code exception rendering, the
:mod:`traceback` module was using qualname already).

..

.. bpo: 45056
.. date: 2021-09-01-16-55-43
.. nonce: 7AK2d9
.. section: Core and Builtins

Compiler now removes trailing unused constants from co_consts.

..

.. bpo: 27946
.. date: 2021-12-04-20-08-42
.. nonce: -Vuarf
.. section: Library

Fix possible crash when getting an attribute of
class:`xml.etree.ElementTree.Element` simultaneously with replacing the
``attrib`` dict.

..

.. bpo: 37658
.. date: 2021-11-28-15-30-34
.. nonce: 8Hno7d
.. section: Library

Fix issue when on certain conditions ``asyncio.wait_for()`` may allow a
coroutine to complete successfully, but fail to return the result,
potentially causing memory leaks or other issues.

..

.. bpo: 44649
.. date: 2021-11-21-20-50-42
.. nonce: E8M936
.. section: Library

Handle dataclass(slots=True) with a field that has default a default value,
but for which init=False.

..

.. bpo: 45803
.. date: 2021-11-20-17-04-25
.. nonce: wSgFOy
.. section: Library

Added missing kw_only parameter to dataclasses.make_dataclass().

..

.. bpo: 45831
.. date: 2021-11-17-19-25-37
.. nonce: 9-TojK
.. section: Library

:mod:`faulthandler` can now write ASCII-only strings (like filenames and
function names) with a single write() syscall when dumping a traceback. It
reduces the risk of getting an unreadable dump when two threads or two
processes dump a traceback to the same file (like stderr) at the same time.
Patch by Victor Stinner.

..

.. bpo: 41735
.. date: 2021-11-16-18-13-49
.. nonce: D72UY1
.. section: Library

Fix thread lock in ``zlib.Decompress.flush()`` method before
``PyObject_GetBuffer``.

..

.. bpo: 45235
.. date: 2021-11-11-13-03-17
.. nonce: 8ZbkHa
.. section: Library

Reverted an argparse bugfix that caused regression in the handling of
default arguments for subparsers.  This prevented leaf level arguments from
taking precedence over root level arguments.

..

.. bpo: 45765
.. date: 2021-11-09-09-04-19
.. nonce: JVobxK
.. section: Library

In importlib.metadata, fix distribution discovery for an empty path.

..

.. bpo: 45757
.. date: 2021-11-08-23-22-14
.. nonce: MHZHt3
.. section: Library

Fix bug where :mod:`dis` produced an incorrect oparg when
:opcode:`EXTENDED_ARG` is followed by an opcode that does not use its
argument.

..

.. bpo: 45644
.. date: 2021-11-06-17-47-46
.. nonce: ZMqHD_
.. section: Library

In-place JSON file formatting using ``python3 -m json.tool infile infile``
now works correctly, previously it left the file empty.  Patch by Chris
Wesseling.

..

.. bpo: 45679
.. date: 2021-10-30-21-11-37
.. nonce: Dq8Cpu
.. section: Library

Fix caching of multi-value :data:`typing.Literal`. ``Literal[True, 2]`` is
no longer equal to ``Literal[1, 2]``.

..

.. bpo: 45664
.. date: 2021-10-28-23-40-54
.. nonce: 7dqtxQ
.. section: Library

Fix :func:`types.resolve_bases` and :func:`types.new_class` for
:class:`types.GenericAlias` instance as a base.

..

.. bpo: 45663
.. date: 2021-10-28-23-11-59
.. nonce: J90N5R
.. section: Library

Fix :func:`dataclasses.is_dataclass` for dataclasses which are subclasses of
:class:`types.GenericAlias`.

..

.. bpo: 45662
.. date: 2021-10-28-22-58-14
.. nonce: sJd7Ir
.. section: Library

Fix the repr of :data:`dataclasses.InitVar` with a type alias to the
built-in class, e.g. ``InitVar[list[int]]``.

..

.. bpo: 45438
.. date: 2021-10-27-10-05-39
.. nonce: Xz5lGU
.. section: Library

Fix typing.Signature string representation for generic builtin types.

..

.. bpo: 45574
.. date: 2021-10-22-23-06-33
.. nonce: svqA84
.. section: Library

Fix warning about ``print_escape`` being unused.

..

.. bpo: 45581
.. date: 2021-10-22-21-57-02
.. nonce: rlH6ay
.. section: Library

:meth:`sqlite3.connect` now correctly raises :exc:`MemoryError` if the
underlying SQLite API signals memory error. Patch by Erlend E. Aasland.

..

.. bpo: 45557
.. date: 2021-10-21-16-18-51
.. nonce: 4MQt4r
.. section: Library

pprint.pprint() now handles underscore_numbers correctly. Previously it was
always setting it to False.

..

.. bpo: 45515
.. date: 2021-10-18-14-52-48
.. nonce: aXdvm_
.. section: Library

Add references to :mod:`zoneinfo` in the :mod:`datetime` documentation,
mostly replacing outdated references to ``dateutil.tz``. Change by Paul
Ganssle.

..

.. bpo: 45475
.. date: 2021-10-18-10-46-47
.. nonce: sb9KDF
.. section: Library

Reverted optimization of iterating :class:`gzip.GzipFile`,
:class:`bz2.BZ2File`, and :class:`lzma.LZMAFile` (see bpo-43787) because it
caused regression when user iterate them without having reference of them.
Patch by Inada Naoki.

..

.. bpo: 45428
.. date: 2021-10-14-18-04-17
.. nonce: mM2War
.. section: Library

Fix a regression in py_compile when reading filenames from standard input.

..

.. bpo: 45467
.. date: 2021-10-14-13-31-19
.. nonce: Q7Ma6A
.. section: Library

Fix incremental decoder and stream reader in the "raw-unicode-escape" codec.
Previously they failed if the escape sequence was split.

..

.. bpo: 45461
.. date: 2021-10-14-00-19-02
.. nonce: 4LB_tJ
.. section: Library

Fix incremental decoder and stream reader in the "unicode-escape" codec.
Previously they failed if the escape sequence was split.

..

.. bpo: 45239
.. date: 2021-10-13-17-52-48
.. nonce: 7li1_0
.. section: Library

Fixed :func:`email.utils.parsedate_tz` crashing with
:exc:`UnboundLocalError` on certain invalid input instead of returning
``None``. Patch by Ben Hoyt.

..

.. bpo: 45249
.. date: 2021-10-10-16-14-33
.. nonce: xqLliz
.. section: Library

Fix the behaviour of :func:`traceback.print_exc` when displaying the caret
when the ``end_offset`` in the exception is set to 0. Patch by Pablo Galindo

..

.. bpo: 45416
.. date: 2021-10-10-09-42-34
.. nonce: n35O0_
.. section: Library

Fix use of :class:`asyncio.Condition` with explicit :class:`asyncio.Lock`
objects, which was a regression due to removal of explicit loop arguments.
Patch by Joongi Kim.

..

.. bpo: 45419
.. date: 2021-10-09-20-53-13
.. nonce: CauCgt
.. section: Library

Correct interfaces on DegenerateFiles.Path.

..

.. bpo: 44904
.. date: 2021-10-09-18-42-27
.. nonce: RlW5h8
.. section: Library

Fix bug in the :mod:`doctest` module that caused it to fail if a docstring
included an example with a ``classmethod`` ``property``. Patch by Alex
Waygood.

..

.. bpo: 45406
.. date: 2021-10-08-19-24-48
.. nonce: Qh_Mz4
.. section: Library

Make :func:`inspect.getmodule` catch ``FileNotFoundError`` raised by
:'func:`inspect.getabsfile`, and return ``None`` to indicate that the module
could not be determined.

..

.. bpo: 45262
.. date: 2021-10-07-14-04-10
.. nonce: HqF71Z
.. section: Library

Prevent use-after-free in asyncio. Make sure the cached running loop holder
gets cleared on dealloc to prevent use-after-free in get_running_loop

..

.. bpo: 45386
.. date: 2021-10-07-00-05-05
.. nonce: q9ORpA
.. section: Library

Make :mod:`xmlrpc.client` more robust to C runtimes where the underlying C
``strftime`` function results in a ``ValueError`` when testing for year
formatting options.

..

.. bpo: 45371
.. date: 2021-10-05-11-03-48
.. nonce: NOwcDJ
.. section: Library

Fix clang rpath issue in :mod:`distutils`. The UnixCCompiler now uses
correct clang option to add a runtime library directory (rpath) to a shared
library.

..

.. bpo: 20028
.. date: 2021-10-03-21-14-37
.. nonce: zBA4RK
.. section: Library

Improve error message of :class:`csv.Dialect` when initializing. Patch by
Vajrasky Kok and Dong-hee Na.

..

.. bpo: 45343
.. date: 2021-10-01-23-07-02
.. nonce: ixmctD
.. section: Library

Update bundled pip to 21.2.4 and setuptools to 58.1.0

..

.. bpo: 45329
.. date: 2021-10-01-13-09-53
.. nonce: 9iMYaO
.. section: Library

Fix freed memory access in :class:`pyexpat.xmlparser` when building it with
an installed expat library <= 2.2.0.

..

.. bpo: 41710
.. date: 2021-09-30-23-00-18
.. nonce: svuloZ
.. section: Library

On Unix, if the ``sem_clockwait()`` function is available in the C library
(glibc 2.30 and newer), the :meth:`threading.Lock.acquire` method now uses
the monotonic clock (:data:`time.CLOCK_MONOTONIC`) for the timeout, rather
than using the system clock (:data:`time.CLOCK_REALTIME`), to not be
affected by system clock changes. Patch by Victor Stinner.

..

.. bpo: 45328
.. date: 2021-09-30-08-22-44
.. nonce: 8Z-Q0B
.. section: Library

Fixed :class:`http.client.HTTPConnection` to work properly in OSs that don't
support the ``TCP_NODELAY`` socket option.

..

.. bpo: 1596321
.. date: 2021-09-24-17-20-23
.. nonce: 3nhPUk
.. section: Library

Fix the :func:`threading._shutdown` function when the :mod:`threading`
module was imported first from a thread different than the main thread: no
longer log an error at Python exit.

..

.. bpo: 45274
.. date: 2021-09-23-22-17-26
.. nonce: gPpa4E
.. section: Library

Fix a race condition in the :meth:`Thread.join() <threading.Thread.join>`
method of the :mod:`threading` module. If the function is interrupted by a
signal and the signal handler raises an exception, make sure that the thread
remains in a consistent state to prevent a deadlock. Patch by Victor
Stinner.

..

.. bpo: 45238
.. date: 2021-09-18-16-56-33
.. nonce: Hng_9V
.. section: Library

Fix :meth:`unittest.IsolatedAsyncioTestCase.debug`: it runs now asynchronous
methods and callbacks.

..

.. bpo: 36674
.. date: 2021-09-18-13-14-57
.. nonce: a2k5Zb
.. section: Library

:meth:`unittest.TestCase.debug` raises now a :class:`unittest.SkipTest` if
the class or the test method are decorated with the skipping decorator.

..

.. bpo: 45235
.. date: 2021-09-17-16-55-37
.. nonce: sXnmPA
.. section: Library

Fix an issue where argparse would not preserve values in a provided
namespace when using a subparser with defaults.

..

.. bpo: 45183
.. date: 2021-09-17-15-58-53
.. nonce: Vv_vch
.. section: Library

Have zipimport.zipimporter.find_spec() not raise an exception when the
underlying zip file has been deleted and the internal cache has been reset
via invalidate_cache().

..

.. bpo: 45234
.. date: 2021-09-17-11-20-55
.. nonce: qUcTVt
.. section: Library

Fixed a regression in :func:`~shutil.copyfile`, :func:`~shutil.copy`,
:func:`~shutil.copy2` raising :exc:`FileNotFoundError` when source is a
directory, which should raise :exc:`IsADirectoryError`

..

.. bpo: 45228
.. date: 2021-09-17-09-59-33
.. nonce: WV1dcT
.. section: Library

Fix stack buffer overflow in parsing J1939 network address.

..

.. bpo: 45192
.. date: 2021-09-14-15-52-47
.. nonce: DjA-BI
.. section: Library

Fix the ``tempfile._infer_return_type`` function so that the ``dir``
argument of the :mod:`tempfile` functions accepts an object implementing the
``os.PathLike`` protocol.

Patch by Kyungmin Lee.

..

.. bpo: 42135
.. date: 2021-09-13-19-32-58
.. nonce: 1ZAHqR
.. section: Library

Fix typo: ``importlib.find_loader`` is really slated for removal in Python
3.12 not 3.10, like the others in GH-25169.

Patch by Hugo van Kemenade.

..

.. bpo: 45160
.. date: 2021-09-11-14-47-05
.. nonce: VzMXbW
.. section: Library

When tracing a tkinter variable used by a ttk OptionMenu, callbacks are no
longer made twice.

..

.. bpo: 35474
.. date: 2021-09-11-10-45-12
.. nonce: tEY3SD
.. section: Library

Calling :func:`mimetypes.guess_all_extensions` with ``strict=False`` no
longer affects the result of the following call with ``strict=True``. Also,
mutating the returned list no longer affects the global state.

..

.. bpo: 45166
.. date: 2021-09-10-21-35-53
.. nonce: UHipXF
.. section: Library

:func:`typing.get_type_hints` now works with :data:`~typing.Final` wrapped
in :class:`~typing.ForwardRef`.

..

.. bpo: 20499
.. date: 2021-09-08-01-19-31
.. nonce: tSxx8Y
.. section: Library

Improve the speed and accuracy of statistics.pvariance().

..

.. bpo: 24444
.. date: 2021-08-30-00-19-23
.. nonce: Ki4bgz
.. section: Library

Fixed an error raised in :mod:`argparse` help display when help for an
option is set to 1+ blank spaces or when *choices* arg is an empty
container.

..

.. bpo: 45021
.. date: 2021-08-28-13-00-12
.. nonce: rReeaj
.. section: Library

Fix a potential deadlock at shutdown of forked children when using
:mod:`concurrent.futures` module

..

.. bpo: 39039
.. date: 2021-08-18-10-36-14
.. nonce: A63LYh
.. section: Library

tarfile.open raises :exc:`~tarfile.ReadError` when a zlib error occurs
during file extraction.

..

.. bpo: 44594
.. date: 2021-07-12-10-32-48
.. nonce: eEa5zi
.. section: Library

Fix an edge case of :class:`ExitStack` and :class:`AsyncExitStack` exception
chaining.  They will now match ``with`` block behavior when ``__context__``
is explicitly set to ``None`` when the exception is in flight.

..

.. bpo: 44295
.. date: 2021-06-02-16-39-42
.. nonce: erg01m
.. section: Library

Ensure deprecation warning from :func:`assertDictContainsSubset` points at
calling code - by Anthony Sottile.

..

.. bpo: 43498
.. date: 2021-04-20-14-14-16
.. nonce: L_Hq-8
.. section: Library

Avoid a possible *"RuntimeError: dictionary changed size during iteration"*
when adjusting the process count of :class:`ProcessPoolExecutor`.

..

.. bpo: 45640
.. date: 2021-11-18-16-44-12
.. nonce: lSpc2A
.. section: Documentation

Properly marked-up grammar tokens in the documentation are now clickable and
take you to the definition of a given piece of grammar.  Patch by Arthur
Milchior.

..

.. bpo: 45788
.. date: 2021-11-18-00-07-40
.. nonce: qibUoB
.. section: Documentation

Link doc for sys.prefix to sysconfig doc on installation paths.

..

.. bpo: 45772
.. date: 2021-11-09-13-10-55
.. nonce: EdrM3t
.. section: Documentation

``socket.socket`` documentation is corrected to a class from a function.

..

.. bpo: 45392
.. date: 2021-11-06-10-54-17
.. nonce: JZnVOz
.. section: Documentation

Update the docstring of the :class:`type` built-in to remove a redundant
line and to mention keyword arguments for the constructor.

..

.. bpo: 45726
.. date: 2021-11-05-12-15-24
.. nonce: GwRr7e
.. section: Documentation

Improve documentation for :func:`functools.singledispatch` and
:class:`functools.singledispatchmethod`.

..

.. bpo: 45680
.. date: 2021-11-03-14-51-03
.. nonce: 9_NTFU
.. section: Documentation

Amend the docs on ``GenericAlias`` objects to clarify that non-container
classes can also implement ``__class_getitem__``. Patch contributed by Alex
Waygood.

..

.. bpo: 45655
.. date: 2021-10-28-19-22-55
.. nonce: aPYGaS
.. section: Documentation

Add a new "relevant PEPs" section to the top of the documentation for the
``typing`` module. Patch by Alex Waygood.

..

.. bpo: 45604
.. date: 2021-10-26-10-00-45
.. nonce: Dm-YhV
.. section: Documentation

Add ``level`` argument to ``multiprocessing.log_to_stderr`` function docs.

..

.. bpo: 45250
.. date: 2021-10-22-12-09-18
.. nonce: Iit5-Y
.. section: Documentation

Update the documentation to note that CPython does not consistently require
iterators to define ``__iter__``.

..

.. bpo: 45464
.. date: 2021-10-20-16-26-53
.. nonce: mOISBs
.. section: Documentation

Mention in the documentation of :ref:`Built-in Exceptions
<bltin-exceptions>` that inheriting from multiple exception types in a
single subclass is not recommended due to possible memory layout
incompatibility.

..

.. bpo: 45449
.. date: 2021-10-19-01-41-40
.. nonce: fjHZJc
.. section: Documentation

Add note about :pep:`585` in :mod:`collections.abc`.

..

.. bpo: 45516
.. date: 2021-10-18-20-12-18
.. nonce: EJh4K8
.. section: Documentation

Add protocol description to the :class:`importlib.abc.Traversable`
documentation.

..

.. bpo: 20692
.. date: 2021-10-13-00-42-54
.. nonce: K5rGtP
.. section: Documentation

Add Programming FAQ entry explaining that int literal attribute access
requires either a space after or parentheses around the literal.

..

.. bpo: 45216
.. date: 2021-09-18-13-45-19
.. nonce: o56nyt
.. section: Documentation

Remove extra documentation listing methods in ``difflib``. It was rendering
twice in pydoc and was outdated in some places.

..

.. bpo: 45024
.. date: 2021-09-08-17-20-19
.. nonce: dkNPNi
.. section: Documentation

:mod:`collections.abc` documentation has been expanded to explicitly cover
how instance and subclass checks work, with additional doctest examples and
an exhaustive list of ABCs which test membership purely by presence of the
right :term:`special method`\s. Patch by Raymond Hettinger.

..

.. bpo: 25381
.. date: 2021-06-21-17-51-51
.. nonce: 7Kn-_H
.. section: Documentation

In the extending chapter of the extending doc, update a paragraph about the
global variables containing exception information.

..

.. bpo: 43905
.. date: 2021-05-24-05-00-12
.. nonce: tBIndE
.. section: Documentation

Expanded :func:`~dataclasses.astuple` and :func:`~dataclasses.asdict` docs,
warning about deepcopy being applied and providing a workaround.

..

.. bpo: 19460
.. date: 2021-11-28-15-25-02
.. nonce: lr0aWs
.. section: Tests

Add new Test for :class:`email.mime.nonmultipart.MIMENonMultipart`.

..

.. bpo: 45835
.. date: 2021-11-17-14-28-08
.. nonce: Mgyhjx
.. section: Tests

Fix race condition in test_queue tests with multiple "feeder" threads.

..

.. bpo: 45678
.. date: 2021-11-04-20-03-32
.. nonce: 1xNMjN
.. section: Tests

Add tests for scenarios in which :class:`functools.singledispatchmethod` is
stacked on top of a method that has already been wrapped by two other
decorators. Patch by Alex Waygood.

..

.. bpo: 45578
.. date: 2021-10-30-19-00-25
.. nonce: bvu6X2
.. section: Tests

Add tests for :func:`dis.distb`

..

.. bpo: 45678
.. date: 2021-10-30-13-12-20
.. nonce: bKrYeS
.. section: Tests

Add tests to ensure that ``functools.singledispatchmethod`` correctly wraps
the attributes of the target function.

..

.. bpo: 45577
.. date: 2021-10-22-19-44-13
.. nonce: dSaNvK
.. section: Tests

Add subtests for all ``pickle`` protocols in ``test_zoneinfo``.

..

.. bpo: 45566
.. date: 2021-10-22-12-05-21
.. nonce: 2gQ3ZB
.. section: Tests

Fix ``test_frozen_pickle`` in ``test_dataclasses`` to check all ``pickle``
versions.

..

.. bpo: 43592
.. date: 2021-10-21-17-22-26
.. nonce: kHRsra
.. section: Tests

:mod:`test.libregrtest` now raises the soft resource limit for the maximum
number of file descriptors when the default is too low for our test suite as
was often the case on macOS.

..

.. bpo: 39679
.. date: 2021-10-18-16-18-41
.. nonce: F18qcE
.. section: Tests

Add more test cases for `@functools.singledispatchmethod` when combined with
`@classmethod` or `@staticmethod`.

..

.. bpo: 45400
.. date: 2021-10-07-13-11-45
.. nonce: h3iT7V
.. section: Tests

Fix test_name_error_suggestions_do_not_trigger_for_too_many_locals() of
test_exceptions if a directory name contains "a1" (like "Python-3.11.0a1"):
use a stricter regular expression. Patch by Victor Stinner.

..

.. bpo: 40173
.. date: 2021-09-30-16-54-39
.. nonce: J_slCw
.. section: Tests

Fix :func:`test.support.import_helper.import_fresh_module`.

..

.. bpo: 45280
.. date: 2021-09-25-11-05-31
.. nonce: 3MA6lC
.. section: Tests

Add a test case for empty :class:`typing.NamedTuple`.

..

.. bpo: 45269
.. date: 2021-09-24-10-41-49
.. nonce: 8jKEr8
.. section: Tests

Cover case when invalid ``markers`` type is supplied to ``c_make_encoder``.

..

.. bpo: 45128
.. date: 2021-09-16-17-22-35
.. nonce: Jz6fl2
.. section: Tests

Fix ``test_multiprocessing_fork`` failure due to ``test_logging`` and
``sys.modules`` manipulation.

..

.. bpo: 45209
.. date: 2021-09-15-23-32-39
.. nonce: 55ntL5
.. section: Tests

Fix ``UserWarning: resource_tracker`` warning in
``_test_multiprocessing._TestSharedMemory.test_shared_memory_cleaned_after_process_termination``

..

.. bpo: 45195
.. date: 2021-09-14-13-16-18
.. nonce: EyQR1G
.. section: Tests

Fix test_readline.test_nonascii(): sometimes, the newline character is not
written at the end, so don't expect it in the output. Patch by Victor
Stinner.

..

.. bpo: 45156
.. date: 2021-09-13-00-28-17
.. nonce: 8oomV3
.. section: Tests

Fixes infinite loop on :func:`unittest.mock.seal` of mocks created by
:func:`~unittest.create_autospec`.

..

.. bpo: 45125
.. date: 2021-09-11-22-08-18
.. nonce: FVSzs2
.. section: Tests

Improves pickling tests and docs of ``SharedMemory`` and ``SharableList``
objects.

..

.. bpo: 44860
.. date: 2021-09-08-13-01-37
.. nonce: qXd0kx
.. section: Tests

Update ``test_sysconfig.test_user_similar()`` for the posix_user scheme:
``platlib`` doesn't use :data:`sys.platlibdir`. Patch by Victor Stinner.

..

.. bpo: 25130
.. date: 2021-08-27-22-37-19
.. nonce: ig4oJe
.. section: Tests

Add calls of :func:`gc.collect` in tests to support PyPy.

..

.. bpo: 44035
.. date: 2021-12-06-09-31-27
.. nonce: BiO4XC
.. section: Build

CI now verifies that autoconf files have been regenerated with a current and
unpatched autoconf package.

..

.. bpo: 33393
.. date: 2021-11-25-20-26-06
.. nonce: 24YNtM
.. section: Build

Update ``config.guess`` to 2021-06-03 and ``config.sub`` to 2021-08-14.
``Makefile`` now has an ``update-config`` target to make updating more
convenient.

..

.. bpo: 45866
.. date: 2021-11-25-13-53-36
.. nonce: ZH1W8N
.. section: Build

``make regen-all`` now produces the same output when run from a directory
other than the source tree: when building Python out of the source tree.
pegen now strips directory of the "generated by pygen from <FILENAME>"
header Patch by Victor Stinner.

..

.. bpo: 41498
.. date: 2021-11-25-09-15-04
.. nonce: qAk5eo
.. section: Build

Python now compiles on platforms without ``sigset_t``. Several functions in
:mod:`signal` are not available when ``sigset_t`` is missing.

Based on patch by Roman Yurchak for pyodide.

..

.. bpo: 45881
.. date: 2021-11-24-17-14-06
.. nonce: GTXXLk
.. section: Build

``setup.py`` now uses ``CC`` from environment first to discover multiarch
and cross compile paths.

..

.. bpo: 43158
.. date: 2021-11-01-12-51-46
.. nonce: fghS6w
.. section: Build

``setup.py`` now uses values from configure script to build the ``_uuid``
extension module. Configure now detects util-linux's ``libuuid``, too.

..

.. bpo: 45571
.. date: 2021-10-22-15-28-29
.. nonce: yY8NsJ
.. section: Build

``Modules/Setup`` now use ``PY_CFLAGS_NODIST`` instead of ``PY_CFLAGS`` to
compile shared modules.

..

.. bpo: 45561
.. date: 2021-10-21-14-38-30
.. nonce: PVqhZE
.. section: Build

Run smelly.py tool from $(srcdir).

..

.. bpo: 45532
.. date: 2021-10-20-16-07-39
.. nonce: kyhvis
.. section: Build

Update :data:`sys.version` to use ``main`` as fallback information. Patch by
Jeong YunWon.

..

.. bpo: 45536
.. date: 2021-10-20-12-42-39
.. nonce: oQNYHB
.. section: Build

The ``configure`` script now checks whether OpenSSL headers and libraries
provide required APIs. Most common APIs are verified. The check detects
outdated or missing OpenSSL. Failures do not stop configure.

..

.. bpo: 45221
.. date: 2021-10-18-10-25-56
.. nonce: rnulhf
.. section: Build

Fixed regression in handling of ``LDFLAGS`` and ``CPPFLAGS`` options where
:meth:`argparse.parse_known_args` could interpret an option as one of the
built-in command line argument, for example ``-h`` for help.

..

.. bpo: 45405
.. date: 2021-10-11-16-27-38
.. nonce: iSfdW5
.. section: Build

Prevent ``internal configure error`` when running ``configure`` with recent
versions of non-Apple clang.  Patch by David Bohman.

..

.. bpo: 45220
.. date: 2021-09-16-18-00-43
.. nonce: TgbkvW
.. section: Build

Avoid building with the Windows 11 SDK previews automatically. This may be
overridden by setting the ``DefaultWindowsSDKVersion`` environment variable
before building.

..

.. bpo: 45067
.. date: 2021-09-09-16-45-26
.. nonce: mFmY92
.. section: Build

The ncurses function extended_color_content was introduced in 2017

(https://invisible-island.net/ncurses/NEWS.html#index-t20170401).  The

ncurses-devel package in CentOS 7 had a older version ncurses resulted in
compilation error.  For compiling ncurses with extended color support, we
verify the version of the ncurses library >= 20170401.

..

.. bpo: 45901
.. date: 2021-11-26-18-17-41
.. nonce: c5IBqM
.. section: Windows

When installed through the Microsoft Store and set as the default app for
:file:`*.py` files, command line arguments will now be passed to Python when
invoking a script without explicitly launching Python (that is, ``script.py
args`` rather than ``python script.py args``).

..

.. bpo: 45616
.. date: 2021-11-23-11-44-42
.. nonce: K52PLZ
.. section: Windows

Fix Python Launcher's ability to distinguish between versions 3.1 and 3.10
when either one is explicitly requested.  Previously, 3.1 would be used if
3.10 was requested but not installed, and 3.10 would be used if 3.1 was
requested but 3.10 was installed.

..

.. bpo: 45732
.. date: 2021-11-08-21-53-11
.. nonce: idl5kx
.. section: Windows

Updates bundled Tcl/Tk to 8.6.12.

..

.. bpo: 45720
.. date: 2021-11-05-01-05-46
.. nonce: 47Nc5I
.. section: Windows

Internal reference to :file:`shlwapi.dll` was dropped to help improve
startup time. This DLL will no longer be loaded at the start of every Python
process.

..

.. bpo: 43652
.. date: 2021-11-04-00-41-50
.. nonce: RnqV7I
.. section: Windows

Update Tcl/Tk to 8.6.11, actually this time. The previous update incorrectly
included 8.6.10.

..

.. bpo: 45337
.. date: 2021-09-30-23-17-27
.. nonce: qg7U_h
.. section: Windows

venv now warns when the created environment may need to be accessed at a
different path, due to redirections, links or junctions. It also now
correctly installs or upgrades components when the alternate path is
required.

..

.. bpo: 45732
.. date: 2021-12-05-23-52-03
.. nonce: -BWrnh
.. section: macOS

Update python.org macOS installer to use Tcl/Tk 8.6.12.

..

.. bpo: 44828
.. date: 2021-10-25-02-02-21
.. nonce: XBdXlJ
.. section: macOS

Avoid tkinter file dialog failure on macOS 12 Monterey when using the Tk
8.6.11 provided by python.org macOS installers. Patch by Marc Culler of the
Tk project.

..

.. bpo: 34602
.. date: 2021-08-27-16-55-10
.. nonce: ZjHsYJ
.. section: macOS

When building CPython on macOS with ``./configure
--with-undefined-behavior-sanitizer --with-pydebug``, the stack size is now
quadrupled to allow for the entire test suite to pass.

..

.. bpo: 45495
.. date: 2021-10-16-17-20-32
.. nonce: ST8RFt
.. section: IDLE

Add context keywords 'case' and 'match' to completions list.

..

.. bpo: 45296
.. date: 2021-09-27-01-21-59
.. nonce: 9H8rdY
.. section: IDLE

On Windows, change exit/quit message to suggest Ctrl-D, which works, instead
of <Ctrl-Z Return>, which does not work in IDLE.

..

.. bpo: 45193
.. date: 2021-09-15-03-20-06
.. nonce: G61_GV
.. section: IDLE

Make completion boxes appear on Ubuntu again.

..

.. bpo: 44786
.. date: 2021-09-14-11-44-26
.. nonce: DU0LC0
.. section: Tools/Demos

Fix a warning in regular expression in the c-analyzer script.

..

.. bpo: 39026
.. date: 2021-11-09-15-42-11
.. nonce: sUnYWn
.. section: C API

Fix Python.h to build C extensions with Xcode: remove a relative include
from ``Include/cpython/pystate.h``.

..

.. bpo: 45307
.. date: 2021-09-28-12-00-55
.. nonce: 3ETFfX
.. section: C API

Restore the private C API function :func:`_PyImport_FindExtensionObject`. It
will be removed in Python 3.11.

..

.. bpo: 44687
.. date: 2021-09-19-17-18-25
.. nonce: 3fqDRC
.. section: C API

:meth:`BufferedReader.peek` no longer raises :exc:`ValueError` when the
entire file has already been buffered.

..

.. bpo: 44751
.. date: 2021-07-27-17-29-12
.. nonce: 4qmbDG
.. section: C API

Remove ``crypt.h`` include from the public ``Python.h`` header.
