.. bpo: 40791
.. date: 2020-05-28-06-06-47
.. nonce: QGZClX
.. release date: 2020-12-07
.. section: Security

Add ``volatile`` to the accumulator variable in ``hmac.compare_digest``,
making constant-time-defeating optimizations less likely.

..

.. bpo: 42576
.. date: 2020-12-05-22-34-47
.. nonce: lEeEl7
.. section: Core and Builtins

``types.GenericAlias`` will now raise a ``TypeError`` when attempting to
initialize with a keyword argument.  Previously, this would cause the
interpreter to crash if the interpreter was compiled with debug symbols.
This does not affect interpreters compiled for release.  Patch by Ken Jin.

..

.. bpo: 42536
.. date: 2020-12-02-20-23-31
.. nonce: Kx3ZOu
.. section: Core and Builtins

Several built-in and standard library types now ensure that their internal
result tuples are always tracked by the :term:`garbage collector <garbage
collection>`:

- :meth:`collections.OrderedDict.items() <collections.OrderedDict>`

- :meth:`dict.items`

- :func:`enumerate`

- :func:`functools.reduce`

- :func:`itertools.combinations`

- :func:`itertools.combinations_with_replacement`

- :func:`itertools.permutations`

- :func:`itertools.product`

- :func:`itertools.zip_longest`

- :func:`zip`

Previously, they could have become untracked by a prior garbage collection.
Patch by Brandt Bucher.

..

.. bpo: 42500
.. date: 2020-11-30-14-27-29
.. nonce: excVKU
.. section: Core and Builtins

Improve handling of exceptions near recursion limit. Converts a number of
Fatal Errors in RecursionErrors.

..

.. bpo: 42246
.. date: 2020-11-24-14-01-43
.. nonce: c9k9hj
.. section: Core and Builtins

PEP 626: After a return, the f_lineno attribute of a frame is always the
last line executed.

..

.. bpo: 42435
.. date: 2020-11-22-14-34-55
.. nonce: uwlB2W
.. section: Core and Builtins

Speed up comparison of bytes objects with non-bytes objects when option
:option:`-b` is specified. Speed up comparison of bytarray objects with
non-buffer object.

..

.. bpo: 1635741
.. date: 2020-11-18-23-46-31
.. nonce: GVOQ-m
.. section: Library

Port the ``_warnings`` extension module to the multi-phase initialization
API (:pep:`489`). Patch by Victor Stinner.

..

.. bpo: 41686
.. date: 2020-11-17-16-25-50
.. nonce: hX77kL
.. section: Core and Builtins

On Windows, the ``SIGINT`` event, ``_PyOS_SigintEvent()``, is now created
even if Python is configured to not install signal handlers (if
:c:member:`PyConfig.install_signal_handlers` equals to 0, or
``Py_InitializeEx(0)``).

..

.. bpo: 42381
.. date: 2020-11-16-23-45-56
.. nonce: G4AWxL
.. section: Core and Builtins

Allow assignment expressions in set literals and set comprehensions as per
PEP 572. Patch by Pablo Galindo.

..

.. bpo: 42202
.. date: 2020-11-16-18-13-07
.. nonce: ZxenYD
.. section: Core and Builtins

Change function parameters annotations internal representation to tuple of
strings. Patch provided by Yurii Karabas.

..

.. bpo: 42374
.. date: 2020-11-16-17-57-09
.. nonce: t7np1E
.. section: Core and Builtins

Fix a regression introduced by the new parser, where an unparenthesized
walrus operator was not allowed within generator expressions.

..

.. bpo: 42316
.. date: 2020-11-16-17-30-03
.. nonce: _DdmpQ
.. section: Core and Builtins

Allow an unparenthesized walrus in subscript indexes.

..

.. bpo: 42349
.. date: 2020-11-13-17-25-44
.. nonce: JdWxez
.. section: Core and Builtins

Make sure that the compiler front-end produces a well-formed control flow
graph. Be more aggressive in the compiler back-end, as it is now safe to
do so.

..

.. bpo: 42296
.. date: 2020-11-13-13-53-11
.. nonce: DuGrLJ
.. section: Core and Builtins

On Windows, fix a regression in signal handling which prevented to interrupt
a program using CTRL+C. The signal handler can be run in a thread different
than the Python thread, in which case the test deciding if the thread can
handle signals is wrong.

..

.. bpo: 42332
.. date: 2020-11-12-23-16-14
.. nonce: fEQIdk
.. section: Core and Builtins

:class:`types.GenericAlias` objects can now be the targets of weakrefs.

..

.. bpo: 42282
.. date: 2020-11-07-21-02-05
.. nonce: M1W4Wj
.. section: Core and Builtins

Optimise constant subexpressions that appear as part of named expressions
(previously the AST optimiser did not descend into named expressions). Patch
by Nick Coghlan.

..

.. bpo: 42266
.. date: 2020-11-04-23-03-25
.. nonce: G4hGDe
.. section: Core and Builtins

Fixed a bug with the LOAD_ATTR opcode cache that was not respecting
monkey-patching a class-level attribute to make it a descriptor. Patch by
Pablo Galindo.

..

.. bpo: 40077
.. date: 2020-11-03-21-58-27
.. nonce: a9qM1j
.. section: Library

Convert :mod:`queue` to use heap types.

..

.. bpo: 42246
.. date: 2020-11-02-15-48-17
.. nonce: 3CNQEX
.. section: Core and Builtins

Improved accuracy of line tracing events and f_lineno attribute of Frame
objects. See PEP 626 for details.

..

.. bpo: 40077
.. date: 2020-11-02-14-39-48
.. nonce: grY9TG
.. section: Library

Convert :mod:`mmap` to use heap types.

..

.. bpo: 42233
.. date: 2020-11-01-23-34-56
.. nonce: zOSzja
.. section: Core and Builtins

Allow ``GenericAlias`` objects to use :ref:`union type expressions
<types-union>`. This allows expressions like ``list[int] | dict[float,
str]`` where previously a ``TypeError`` would have been thrown.  This also
fixes union type expressions not de-duplicating ``GenericAlias`` objects.
(Contributed by Ken Jin in :issue:`42233`.)

..

.. bpo: 26131
.. date: 2020-10-22-17-27-08
.. nonce: B-Veg7
.. section: Core and Builtins

The import system triggers a ``ImportWarning`` when it falls back to using
``load_module()``.

..

.. bpo: 5054
.. date: 2020-12-04-03-51-12
.. nonce: 53StYZ
.. section: Library

CGIHTTPRequestHandler.run_cgi() HTTP_ACCEPT improperly parsed. Replace the
special purpose getallmatchingheaders with generic get_all method and add
relevant tests.

Original Patch by Martin Panter. Modified by Senthil Kumaran.

..

.. bpo: 42562
.. date: 2020-12-03-22-42-03
.. nonce: 2hPmhi
.. section: Library

Fix issue when dis failed to parse function that has no line numbers. Patch
provided by Yurii Karabas.

..

.. bpo: 17735
.. date: 2020-12-03-22-22-24
.. nonce: Qsaaue
.. section: Library

:func:`inspect.findsource` now raises :exc:`OSError` instead of
:exc:`IndexError` when :attr:`co_lineno` of a code object is greater than
the file length. This can happen, for example, when a file is edited after
it was imported.  PR by Irit Katriel.

..

.. bpo: 42116
.. date: 2020-12-03-15-42-32
.. nonce: yIwroP
.. section: Library

Fix handling of trailing comments by :func:`inspect.getsource`.

..

.. bpo: 42532
.. date: 2020-12-02-07-37-59
.. nonce: ObNep_
.. section: Library

Remove unexpected call of ``__bool__`` when passing a ``spec_arg`` argument
to a Mock.

..

.. bpo: 38200
.. date: 2020-11-28-22-52-57
.. nonce: DuWGlW
.. section: Library

Added itertools.pairwise()

..

.. bpo: 41818
.. date: 2020-11-28-06-34-53
.. nonce: mFSMc2
.. section: Library

Fix test_master_read() so that it succeeds on all platforms that either
raise OSError or return b"" upon reading from master.

..

.. bpo: 42487
.. date: 2020-11-28-04-31-20
.. nonce: iqtC4L
.. section: Library

ChainMap.__iter__ no longer calls __getitem__ on underlying maps

..

.. bpo: 42482
.. date: 2020-11-27-16-46-58
.. nonce: EJC3sd
.. section: Library

:class:`~traceback.TracebackException` no longer holds a reference to the
exception's traceback object. Consequently, instances of TracebackException
for equivalent but non-equal exceptions now compare as equal.

..

.. bpo: 41818
.. date: 2020-11-27-09-19-43
.. nonce: KWYUbL
.. section: Library

Make test_openpty() avoid unexpected success due to number of rows and/or
number of columns being == 0.

..

.. bpo: 42392
.. date: 2020-11-26-12-40-16
.. nonce: GbmdHE
.. section: Library

Remove loop parameter from ``asyncio.subprocess`` and ``asyncio.tasks``
functions. Patch provided by Yurii Karabas.

..

.. bpo: 42392
.. date: 2020-11-25-22-44-59
.. nonce: T_DAEl
.. section: Library

Remove loop parameter from ``asyncio.open_connection`` and
``asyncio.start_server`` functions. Patch provided by Yurii Karabas.

..

.. bpo: 28468
.. date: 2020-11-24-13-18-05
.. nonce: 8Gh2d4
.. section: Library

Add :func:`platform.freedesktop_os_release` function to parse
freedesktop.org ``os-release`` files.

..

.. bpo: 42299
.. date: 2020-11-23-23-42-08
.. nonce: Fdn4Wf
.. section: Library

Removed the ``formatter`` module, which was deprecated in Python 3.4. It is
somewhat obsolete, little used, and not tested. It was originally scheduled
to be removed in Python 3.6, but such removals were delayed until after
Python 2.7 EOL. Existing users should copy whatever classes they use into
their code. Patch by Donghee Na and and Terry J. Reedy.

..

.. bpo: 26131
.. date: 2020-11-22-12-30-26
.. nonce: -HsFPG
.. section: Library

Deprecate zipimport.zipimporter.load_module() in favour of exec_module().

..

.. bpo: 41818
.. date: 2020-11-20-14-44-07
.. nonce: 33soAw
.. section: Library

Updated tests for the pty library. test_basic() has been changed to
test_openpty(); this additionally checks if slave termios and slave winsize
are being set properly by pty.openpty(). In order to add support for
FreeBSD, NetBSD, OpenBSD, and Darwin, this also adds test_master_read(),
which demonstrates that pty.spawn() should not depend on an OSError to exit
from its copy loop.

..

.. bpo: 42392
.. date: 2020-11-20-14-01-29
.. nonce: -OUzvl
.. section: Library

Remove loop parameter from ``__init__`` in all ``asyncio.locks`` and
``asyncio.Queue`` classes. Patch provided by Yurii Karabas.

..

.. bpo: 15450
.. date: 2020-11-20-10-38-34
.. nonce: E-y9PA
.. section: Library

Make :class:`filecmp.dircmp` respect subclassing. Now the
:attr:`filecmp.dircmp.subdirs` behaves as expected when subclassing dircmp.

..

.. bpo: 42413
.. date: 2020-11-19-20-27-51
.. nonce: fjHrHx
.. section: Library

The exception :exc:`socket.timeout` is now an alias of :exc:`TimeoutError`.

..

.. bpo: 31904
.. date: 2020-11-19-16-14-36
.. nonce: 83kf9d
.. section: Library

Support signal module on VxWorks.

..

.. bpo: 42406
.. date: 2020-11-19-10-44-41
.. nonce: r9rNCj
.. section: Library

We fixed an issue in ``pickle.whichmodule`` in which importing
``multiprocessing`` could change the how pickle identifies which module an
object belongs to, potentially breaking the unpickling of those objects.

..

.. bpo: 42403
.. date: 2020-11-19-10-12-39
.. nonce: t7q5AX
.. section: Library

Simplify the :mod:`importlib` external bootstrap code:
``importlib._bootstrap_external`` now uses regular imports to import builtin
modules. When it is imported, the builtin :func:`__import__` function is
already fully working and so can be used to import builtin modules like
:mod:`sys`. Patch by Victor Stinner.

..

.. bpo: 1635741
.. date: 2020-11-19-09-59-07
.. nonce: 7cMypH
.. section: Library

Convert _sre module types to heap types (PEP 384). Patch by Erlend E.
Aasland.

..

.. bpo: 42375
.. date: 2020-11-19-04-13-53
.. nonce: U8bp4s
.. section: Library

subprocess module update for DragonFlyBSD support.

..

.. bpo: 41713
.. date: 2020-11-17-23-00-27
.. nonce: -Us0tf
.. section: Library

Port the ``_signal`` extension module to the multi-phase initialization API
(:pep:`489`). Patch by Victor Stinner and Mohamed Koubaa.

..

.. bpo: 37205
.. date: 2020-11-16-15-08-12
.. nonce: Wh5svI
.. section: Library

:func:`time.time`, :func:`time.perf_counter` and
:func:`time.monotonic` functions can no longer fail with a Python fatal
error, instead raise a regular Python exception on failure.

..

.. bpo: 42328
.. date: 2020-11-15-17-02-00
.. nonce: bqpPlR
.. section: Library

Fixed :meth:`tkinter.ttk.Style.map`. The function accepts now the
representation of the default state as empty sequence (as returned by
``Style.map()``). The structure of the result is now the same on all
platform and does not depend on the value of ``wantobjects``.

..

.. bpo: 42345
.. date: 2020-11-15-15-23-34
.. nonce: hiIR7x
.. section: Library

Fix various issues with ``typing.Literal`` parameter handling (flatten,
deduplicate, use type to cache key). Patch provided by Yurii Karabas.

..

.. bpo: 37205
.. date: 2020-11-14-14-34-32
.. nonce: iDbHrw
.. section: Library

:func:`time.perf_counter` on Windows and :func:`time.monotonic` on macOS
are now system-wide. Previously, they used an offset computed at startup to
reduce the precision loss caused by the float type. Use
:func:`time.perf_counter_ns` and :func:`time.monotonic_ns` added in
Python 3.7 to avoid this precision loss.

..

.. bpo: 42318
.. date: 2020-11-14-13-46-27
.. nonce: wYAcBD
.. section: Library

Fixed support of non-BMP characters in :mod:`tkinter` on macOS.

..

.. bpo: 42350
.. date: 2020-11-13-18-53-50
.. nonce: rsql7V
.. section: Library

Fix the :class:`threading.Thread` class at fork: do nothing if the thread is
already stopped (ex: fork called at Python exit). Previously, an error was
logged in the child process.

..

.. bpo: 42333
.. date: 2020-11-12-18-21-15
.. nonce: J9vFmV
.. section: Library

Port _ssl extension module to heap types.

..

.. bpo: 42014
.. date: 2020-11-10-15-40-56
.. nonce: ShM37l
.. section: Library

The ``onerror`` callback from ``shutil.rmtree`` now receives correct
function when ``os.open`` fails.

..

.. bpo: 42237
.. date: 2020-11-10-14-27-49
.. nonce: F363jO
.. section: Library

Fix ``os.sendfile()`` on illumos.

..

.. bpo: 42308
.. date: 2020-11-10-12-09-13
.. nonce: yaJHH9
.. section: Library

Add :data:`threading.__excepthook__` to allow retrieving the original value
of :func:`threading.excepthook` in case it is set to a broken or a different
value. Patch by Mario Corchero.

..

.. bpo: 42131
.. date: 2020-11-06-18-20-47
.. nonce: l2rjjG
.. section: Library

Implement PEP 451/spec methods on zipimport.zipimporter: find_spec(),
create_module(), and exec_module().

This also allows for the documented deprecation of find_loader(),
find_module(), and load_module().

..

.. bpo: 41877
.. date: 2020-11-05-16-00-03
.. nonce: FHbngM
.. section: Library

Mock objects which are not unsafe will now raise an AttributeError if an
attribute with the prefix asert, aseert, or assrt is accessed, in addition
to this already happening for the prefixes assert or assret.

..

.. bpo: 42264
.. date: 2020-11-05-13-32-41
.. nonce: r4KYUU
.. section: Library

``sqlite3.OptimizedUnicode`` has been undocumented and obsolete since Python
3.3, when it was made an alias to :class:`str`.  It is now deprecated,
scheduled for removal in Python 3.12.

..

.. bpo: 42251
.. date: 2020-11-03-14-15-35
.. nonce: 6TC32V
.. section: Library

Added :func:`threading.gettrace` and :func:`threading.getprofile` to
retrieve the functions set by :func:`threading.settrace` and
:func:`threading.setprofile` respectively. Patch by Mario Corchero.

..

.. bpo: 42249
.. date: 2020-11-03-09-22-56
.. nonce: vfNO2u
.. section: Library

Fixed writing binary Plist files larger than 4 GiB.

..

.. bpo: 42236
.. date: 2020-11-02-23-05-17
.. nonce: aJ6ZBR
.. section: Library

On Unix, the :func:`os.device_encoding` function now returns ``'UTF-8'``
rather than the device encoding if the :ref:`Python UTF-8 Mode <utf8-mode>`
is enabled.

..

.. bpo: 41754
.. date: 2020-11-01-15-07-20
.. nonce: DraSZh
.. section: Library

webbrowser: Ignore *NotADirectoryError* when calling ``xdg-settings``.

..

.. bpo: 42183
.. date: 2020-10-29-11-17-35
.. nonce: 50ZcIi
.. section: Library

Fix a stack overflow error for asyncio Task or Future repr().

The overflow occurs under some circumstances when a Task or Future
recursively returns itself.

..

.. bpo: 42140
.. date: 2020-10-24-04-02-36
.. nonce: miLqvb
.. section: Library

Improve asyncio.wait function to create the futures set just one time.

..

.. bpo: 42133
.. date: 2020-10-23-15-47-47
.. nonce: BzizYV
.. section: Library

Update various modules in the stdlib to fall back on ``__spec__.loader`` when
``__loader__`` isn't defined on a module.

..

.. bpo: 26131
.. date: 2020-10-22-17-26-35
.. nonce: CAsI3O
.. section: Library

The ``load_module()`` methods found in ``importlib`` now trigger a
``DeprecationWarning``.

..

.. bpo: 39825
.. date: 2020-10-20-08-28-26
.. nonce: n6KnG0
.. section: Library

Windows: Change ``sysconfig.get_config_var('EXT_SUFFIX')`` to the expected
full ``platform_tag.extension`` format. Previously it was hard-coded to
``.pyd``, now it is compatible with ``distutils.sysconfig`` and will result
in something like ``.cp38-win_amd64.pyd``. This brings windows into
conformance with the other platforms.

..

.. bpo: 26389
.. date: 2020-10-08-23-51-55
.. nonce: uga44e
.. section: Library

The :func:`traceback.format_exception`,
:func:`traceback.format_exception_only`, and
:func:`traceback.print_exception` functions can now take an exception object
as a positional-only argument.

..

.. bpo: 41889
.. date: 2020-10-01-16-17-11
.. nonce: qLkNh8
.. section: Library

Enum: fix regression involving inheriting a multiply inherited enum

..

.. bpo: 41861
.. date: 2020-10-01-15-44-52
.. nonce: YTqJ7z
.. section: Library

Convert :mod:`sqlite3` to use heap types (PEP 384). Patch by Erlend E.
Aasland.

..

.. bpo: 40624
.. date: 2020-09-08-03-19-04
.. nonce: 0-gYfx
.. section: Library

Added support for the XPath ``!=`` operator in xml.etree

..

.. bpo: 28850
.. date: 2020-09-06-21-55-44
.. nonce: HJNggD
.. section: Library

Fix :meth:`pprint.PrettyPrinter.format` overrides being ignored for contents
of small containers. The :func:`pprint._safe_repr` function was removed.

..

.. bpo: 41625
.. date: 2020-08-24-16-59-04
.. nonce: Cc967V
.. section: Library

Expose the :c:func:`splice` as :func:`os.splice` in the :mod:`os` module.
Patch by Pablo Galindo

..

.. bpo: 34215
.. date: 2020-08-19-20-17-51
.. nonce: _Cv8c-
.. section: Library

Clarify the error message for :exc:`asyncio.IncompleteReadError` when
``expected`` is ``None``.

..

.. bpo: 41543
.. date: 2020-08-14-00-39-04
.. nonce: RpcRjb
.. section: Library

Add async context manager support for contextlib.nullcontext.

..

.. bpo: 21041
.. date: 2020-08-10-15-06-55
.. nonce: cYz1eL
.. section: Library

:attr:`pathlib.PurePath.parents` now supports negative indexing. Patch
contributed by Yaroslav Pankovych.

..

.. bpo: 41332
.. date: 2020-07-18-17-39-28
.. nonce: QRGmA5
.. section: Library

Added missing connect_accepted_socket() method to
``asyncio.AbstractEventLoop``.

..

.. bpo: 12800
.. date: 2020-07-09-11-32-28
.. nonce: fNgWwx
.. section: Library

Extracting a symlink from a tarball should succeed and overwrite the symlink
if it already exists. The fix is to remove the existing file or symlink
before extraction. Based on patch by Chris AtLee, Jeffrey Kintscher, and
Senthil Kumaran.

..

.. bpo: 40968
.. date: 2020-06-18-11-35-16
.. nonce: R8Edbv
.. section: Library

:mod:`urllib.request` and :mod:`http.client` now send ``http/1.1`` ALPN
extension during TLS handshake when no custom context is supplied.

..

.. bpo: 41001
.. date: 2020-06-17-12-24-26
.. nonce: 5mi7b0
.. section: Library

Add :func:`os.eventfd` to provide a low level interface for Linux's event
notification file descriptor.

..

.. bpo: 40816
.. date: 2020-05-29-15-25-41
.. nonce: w61Pob
.. section: Library

Add AsyncContextDecorator to contextlib to support async context manager as
a decorator.

..

.. bpo: 40550
.. date: 2020-05-08-21-30-54
.. nonce: i7GWkb
.. section: Library

Fix time-of-check/time-of-action issue in subprocess.Popen.send_signal.

..

.. bpo: 39411
.. date: 2020-01-21-16-38-25
.. nonce: 9uHFqT
.. section: Library

Add an ``is_async`` identifier to :mod:`pyclbr`'s ``Function`` objects.
Patch by Batuhan Taskaya

..

.. bpo: 35498
.. date: 2018-12-14-13-29-17
.. nonce: LEJHl7
.. section: Library

Add slice support to :attr:`pathlib.PurePath.parents`.

..

.. bpo: 42238
.. date: 2020-11-24-22-54-49
.. nonce: 62EOTu
.. section: Documentation

Tentative to deprecate ``make suspicious`` by first removing it from the CI
and documentation builds, but keeping it around for manual uses.

..

.. bpo: 42153
.. date: 2020-11-15-13-46-31
.. nonce: KjBhx3
.. section: Documentation

Fix the URL for the IMAP protocol documents.

..

.. bpo: 41028
.. date: 2020-06-18-23-37-03
.. nonce: vM8bC8
.. section: Documentation

Language and version switchers, previously maintained in every cpython
branches, are now handled by docsbuild-script.

..

.. bpo: 41473
.. date: 2020-12-04-11-47-09
.. nonce: W_updK
.. section: Tests

Re-enable test_gdb on gdb 9.2 and newer:
https://bugzilla.redhat.com/show_bug.cgi?id=1866884 bug is fixed in gdb
10.1.

..

.. bpo: 42553
.. date: 2020-12-03-13-32-44
.. nonce: 2TRE2N
.. section: Tests

Fix ``test_asyncio.test_call_later()`` race condition: don't measure asyncio
performance in the ``call_later()`` unit test. The test failed randomly on
the CI.

..

.. bpo: 31904
.. date: 2020-12-01-15-51-19
.. nonce: iwetj4
.. section: Tests

Fix test_netrc on VxWorks: create temporary directories using temp_cwd().

..

.. bpo: 31904
.. date: 2020-11-26-11-13-13
.. nonce: ay4g89
.. section: Tests

skip test_getaddrinfo_ipv6_scopeid_symbolic and
test_getnameinfo_ipv6_scopeid_symbolic on VxWorks

..

.. bpo: 31904
.. date: 2020-11-25-17-00-53
.. nonce: ue4hd9
.. section: Tests

skip test_test of test_mailcap on VxWorks

..

.. bpo: 31904
.. date: 2020-11-24-17-26-41
.. nonce: eug834
.. section: Tests

add shell requirement for test_pipes

..

.. bpo: 31904
.. date: 2020-11-23-11-11-29
.. nonce: V3sUZk
.. section: Tests

skip some tests related to fifo on VxWorks

..

.. bpo: 31904
.. date: 2020-11-20-15-07-18
.. nonce: EBJXjJ
.. section: Tests

Fix test_doctest.py failures for VxWorks.

..

.. bpo: 40754
.. date: 2020-11-13-21-51-34
.. nonce: Ekoxkg
.. section: Tests

Include ``_testinternalcapi`` module in Windows installer for test suite

..

.. bpo: 41561
.. date: 2020-09-18-16-14-03
.. nonce: uPnwrW
.. section: Tests

test_ssl: skip test_min_max_version_mismatch when TLS 1.0 is not available

..

.. bpo: 31904
.. date: 2020-05-20-17-28-46
.. nonce: yt83Ge
.. section: Tests

Fix os module failures for VxWorks RTOS.

..

.. bpo: 31904
.. date: 2020-05-20-14-28-48
.. nonce: yJik6k
.. section: Tests

Fix fifo test cases for VxWorks RTOS.

..

.. bpo: 31904
.. date: 2020-11-19-17-01-50
.. nonce: 894dk2
.. section: Build

remove libnet dependency from detect_socket() for VxWorks

..

.. bpo: 42398
.. date: 2020-11-18-11-58-44
.. nonce: Yt5wO8
.. section: Build

Fix a race condition in "make regen-all" when make -jN option is used to run
jobs in parallel. The clinic.py script now only use atomic write to write
files. Moveover, generated files are now left unchanged if the content does
not change, to not change the file modification time.

..

.. bpo: 41617
.. date: 2020-11-13-15-04-53
.. nonce: 98_oaE
.. section: Build

Fix building ``pycore_bitutils.h`` internal header on old clang version
without ``__builtin_bswap16()`` (ex: Xcode 4.6.3 on Mac OS X 10.7). Patch by
Joshua Root and Victor Stinner.

..

.. bpo: 38823
.. date: 2020-11-12-13-45-15
.. nonce: C0z_Fe
.. section: Build

It is no longer possible to build the ``_ctypes`` extension module without
:c:type:`wchar_t` type: remove ``CTYPES_UNICODE`` macro. Anyway, the
:c:type:`wchar_t` type is required to build Python. Patch by Victor Stinner.

..

.. bpo: 42087
.. date: 2020-10-19-15-41-05
.. nonce: 2AhRFP
.. section: Build

Support was removed for AIX 5.3 and below. See :issue:`40680`.

..

.. bpo: 40998
.. date: 2020-06-17-09-05-02
.. nonce: sgqmg9
.. section: Build

Addressed three compiler warnings found by undefined behavior sanitizer
(ubsan).

..

.. bpo: 42120
.. date: 2020-11-16-22-41-02
.. nonce: 9scgko
.. section: Windows

Remove macro definition of ``copysign`` (to ``_copysign``) in headers.

..

.. bpo: 38506
.. date: 2020-11-15-23-01-14
.. nonce: hhdnuP
.. section: Windows

The Windows launcher now properly handles Python 3.10 when listing installed
Python versions.

..

.. bpo: 42504
.. date: 2020-12-02-15-48-40
.. nonce: RQmMOR
.. section: macOS

Fix build on macOS Big Sur when MACOSX_DEPLOYMENT_TARGET=11

..

.. bpo: 41116
.. date: 2020-11-15-16-43-45
.. nonce: oCkbrF
.. section: macOS

Ensure distutils.unixxcompiler.find_library_file can find system provided
libraries on macOS 11.

..

.. bpo: 41100
.. date: 2020-11-01-16-40-23
.. nonce: BApztP
.. section: macOS

Add support for macOS 11 and Apple Silicon systems.

It is now possible to build "Universal 2" binaries using
"--enable-universalsdk --with-universal-archs=universal2".

Binaries build on later macOS versions can be deployed back to older
versions (tested up to macOS 10.9), when using the correct deployment
target. This is tested using Xcode 11 and later.

..

.. bpo: 42232
.. date: 2020-11-01-15-10-28
.. nonce: 2zI1GN
.. section: macOS

Added Darwin specific madvise options to mmap module.

..

.. bpo: 38443
.. date: 2020-10-23-10-26-53
.. nonce: vu64tl
.. section: macOS

The ``--enable-universalsdk`` and ``--with-universal-archs`` options for the
configure script now check that the specified architectures can be used.

..

.. bpo: 42508
.. date: 2020-11-30-19-46-05
.. nonce: fE7w4M
.. section: IDLE

Keep IDLE running on macOS.  Remove obsolete workaround that prevented
running files with shortcuts when using new universal2 installers built on
macOS 11.

..

.. bpo: 42426
.. date: 2020-11-21-17-21-21
.. nonce: kNnPoC
.. section: IDLE

Fix reporting offset of the RE error in searchengine.

..

.. bpo: 42415
.. date: 2020-11-20-01-30-27
.. nonce: CyD-va
.. section: IDLE

Get docstrings for IDLE calltips more often by using inspect.getdoc.

..

.. bpo: 42212
.. date: 2020-11-20-15-11-05
.. nonce: sjzgOf
.. section: Tools/Demos

The smelly.py script now also checks the Python dynamic library and
extension modules, not only the Python static library. Make also the script
more verbose: explain what it does.

..

.. bpo: 36310
.. date: 2020-05-03-01-30-46
.. nonce: xDxxwY
.. section: Tools/Demos

Allow :file:`Tools/i18n/pygettext.py` to detect calls to ``gettext`` in
f-strings.

..

.. bpo: 42423
.. date: 2020-11-21-12-27-19
.. nonce: ByJHhY
.. section: C API

The :c:func:`PyType_FromSpecWithBases` and
:c:func:`PyType_FromModuleAndSpec` functions now accept a single class as
the *bases* argument.

..

.. bpo: 1635741
.. date: 2020-11-19-17-44-36
.. nonce: qBZc3o
.. section: C API

Port :mod:`select` extension module to multiphase initialization
(:pep:`489`).

..

.. bpo: 1635741
.. date: 2020-11-19-16-54-16
.. nonce: 9tVsZt
.. section: C API

Port _posixsubprocess extension module to multiphase initialization
(:pep:`489`).

..

.. bpo: 1635741
.. date: 2020-11-19-15-33-42
.. nonce: 9tVsZt
.. section: C API

Port _posixshmem extension module to multiphase initialization (:pep:`489`)

..

.. bpo: 1635741
.. date: 2020-11-19-12-06-43
.. nonce: KEfZpn
.. section: C API

Port _struct extension module to multiphase initialization (:pep:`489`)

..

.. bpo: 1635741
.. date: 2020-11-19-09-17-01
.. nonce: 6F9o6L
.. section: C API

Port :mod:`!spwd` extension module to multiphase initialization (:pep:`489`)

..

.. bpo: 1635741
.. date: 2020-11-18-20-33-35
.. nonce: B4ztSk
.. section: C API

Port :mod:`gc` extension module to multiphase initialization (:pep:`489`)

..

.. bpo: 1635741
.. date: 2020-11-18-20-11-13
.. nonce: fe3iRb
.. section: C API

Port _queue extension module to multiphase initialization (:pep:`489`)

..

.. bpo: 39573
.. date: 2020-11-18-15-21-59
.. nonce: VB3G2y
.. section: C API

Convert :c:func:`Py_TYPE` and :c:func:`Py_SIZE` back to macros to allow
using them as an l-value. Many third party C extension modules rely on the
ability of using Py_TYPE() and Py_SIZE() to set an object type and size:
``Py_TYPE(obj) = type;`` and ``Py_SIZE(obj) = size;``.

..

.. bpo: 1635741
.. date: 2020-11-18-10-52-38
.. nonce: FrWAwJ
.. section: C API

Port :mod:`symtable` extension module to multiphase initialization
(:pep:`489`)

..

.. bpo: 1635741
.. date: 2020-11-18-09-46-35
.. nonce: SH8OIT
.. section: C API

Port :mod:`grp` and :mod:`pwd` extension modules to multiphase
initialization (:pep:`489`)

..

.. bpo: 1635741
.. date: 2020-11-18-09-16-23
.. nonce: gkoI7Y
.. section: C API

Port _random extension module to multiphase initialization (:pep:`489`)

..

.. bpo: 1635741
.. date: 2020-11-18-08-45-36
.. nonce: VLZfiY
.. section: C API

Port _hashlib extension module to multiphase initialization (:pep:`489`)

..

.. bpo: 41713
.. date: 2020-11-17-15-39-10
.. nonce: Rq99Vc
.. section: C API

Removed the undocumented ``PyOS_InitInterrupts()`` function. Initializing
Python already implicitly installs signal handlers: see
:c:member:`PyConfig.install_signal_handlers`. Patch by Victor Stinner.

..

.. bpo: 40170
.. date: 2020-11-13-01-40-28
.. nonce: uh8lEf
.. section: C API

The ``Py_TRASHCAN_BEGIN`` macro no longer accesses PyTypeObject attributes,
but now can get the condition by calling the new private
:c:func:`!_PyTrash_cond()` function which hides implementation details.

..

.. bpo: 42260
.. date: 2020-11-10-14-27-39
.. nonce: -Br3Co
.. section: C API

:c:func:`Py_GetPath`, :c:func:`Py_GetPrefix`, :c:func:`Py_GetExecPrefix`,
:c:func:`Py_GetProgramFullPath`, :c:func:`Py_GetPythonHome` and
:c:func:`Py_GetProgramName` functions now return ``NULL`` if called before
:c:func:`Py_Initialize` (before Python is initialized). Use the new
:ref:`Python Initialization Configuration API <init-config>` to get the
:ref:`Python Path Configuration.  <init-path-config>`. Patch by Victor
Stinner.

..

.. bpo: 42260
.. date: 2020-11-05-18-02-07
.. nonce: pAeaNR
.. section: C API

The :c:func:`PyConfig_Read` function now only parses
:c:member:`PyConfig.argv` arguments once: :c:member:`PyConfig.parse_argv` is
set to ``2`` after arguments are parsed. Since Python arguments are
strippped from :c:member:`PyConfig.argv`, parsing arguments twice would
parse the application options as Python options.

..

.. bpo: 42262
.. date: 2020-11-04-17-22-36
.. nonce: fCWzBb
.. section: C API

Added :c:func:`Py_NewRef` and :c:func:`Py_XNewRef` functions to increment
the reference count of an object and return the object. Patch by Victor
Stinner.

..

.. bpo: 42260
.. date: 2020-11-04-16-31-55
.. nonce: CmgHtF
.. section: C API

When :c:func:`Py_Initialize` is called twice, the second call now updates
more :mod:`sys` attributes for the configuration, rather than only
:data:`sys.argv`. Patch by Victor Stinner.

..

.. bpo: 41832
.. date: 2020-11-03-19-47-06
.. nonce: dL1VJJ
.. section: C API

The :c:func:`PyType_FromModuleAndSpec` function now accepts NULL ``tp_doc``
slot.

..

.. bpo: 1635741
.. date: 2020-11-03-11-52-27
.. nonce: aDYJKB
.. section: C API

Added :c:func:`PyModule_AddObjectRef` function: similar to
:c:func:`PyModule_AddObject` but don't steal a reference to the value on
success. Patch by Victor Stinner.

..

.. bpo: 42171
.. date: 2020-10-27-21-10-14
.. nonce: S3FWTP
.. section: C API

The :c:macro:`METH_FASTCALL` calling convention is added to the limited API.
The functions  :c:func:`PyModule_AddType`,
:c:func:`PyType_FromModuleAndSpec`, :c:func:`PyType_GetModule` and
:c:func:`PyType_GetModuleState` are added to the limited API on Windows.

..

.. bpo: 42085
.. date: 2020-10-19-15-58-16
.. nonce: NhEf3W
.. section: C API

Add dedicated entry to PyAsyncMethods for sending values

..

.. bpo: 41073
.. date: 2020-07-08-21-01-49
.. nonce: VqQZON
.. section: C API

:c:func:`PyType_GetSlot()` can now accept static types.

..

.. bpo: 30459
.. date: 2020-05-06-23-54-57
.. nonce: N9_Jai
.. section: C API

:c:func:`PyList_SET_ITEM`, :c:func:`PyTuple_SET_ITEM` and
:c:func:`PyCell_SET` macros can no longer be used as l-value or r-value. For
example, ``x = PyList_SET_ITEM(a, b, c)`` and ``PyList_SET_ITEM(a, b, c) =
x`` now fail with a compiler error. It prevents bugs like ``if
(PyList_SET_ITEM (a, b, c) < 0) ...`` test. Patch by Zackery Spytz and
Victor Stinner.
