.. bpo: 42967
.. date: 2021-02-14-15-59-16
.. nonce: YApqDS
.. release date: 2021-02-16
.. section: Security

Fix web cache poisoning vulnerability by defaulting the query args separator
to ``&``, and allowing the user to choose a custom separator.

..

.. bpo: 42938
.. date: 2021-01-18-09-27-31
.. nonce: 4Zn4Mp
.. section: Security

Avoid static buffers when computing the repr of :class:`ctypes.c_double` and
:class:`ctypes.c_longdouble` values.

..

.. bpo: 42819
.. date: 2021-01-04-23-54-34
.. nonce: 4KO6wU
.. section: Core and Builtins

:mod:`readline`: Explicitly disable bracketed paste in the interactive
interpreter, even if it's set in the inputrc, is enabled by default (eg GNU
Readline 8.1), or a user calls ``readline.read_init_file()``. The Python
REPL has not implemented bracketed paste support. Also, bracketed mode
writes the ``"\x1b[?2004h"`` escape sequence into stdout which causes test
failures in applications that don't support it. It can still be explicitly
enabled by calling ``readline.parse_and_bind("set enable-bracketed-paste
on")``. Patch by Dustin Rodrigues.

..

.. bpo: 42806
.. date: 2021-01-03-00-20-38
.. nonce: mLAobJ
.. section: Core and Builtins

Fix the column offsets for f-strings :mod:`ast` nodes surrounded by
parentheses and for nodes that spawn multiple lines. Patch by Pablo Galindo.

..

.. bpo: 40631
.. date: 2020-12-31-20-58-22
.. nonce: deRMCx
.. section: Core and Builtins

Fix regression where a single parenthesized starred expression was a valid
assignment target.

..

.. bpo: 32381
.. date: 2020-12-04-17-17-44
.. nonce: NY5t2S
.. section: Core and Builtins

Fix encoding name when running a ``.pyc`` file on Windows:
:c:func:`PyRun_SimpleFileExFlags()` now uses the correct encoding to decode
the filename.

..

.. 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: 42195
.. date: 2020-11-20-00-57-47
.. nonce: HeqcpS
.. section: Core and Builtins

The ``__args__`` of the parameterized generics for :data:`typing.Callable`
and :class:`collections.abc.Callable` are now consistent.  The ``__args__``
for :class:`collections.abc.Callable` are now flattened while
:data:`typing.Callable`'s have not changed.  To allow this change,
:class:`types.GenericAlias` can now be subclassed and
``collections.abc.Callable``'s ``__class_getitem__`` will now return a
subclass of ``types.GenericAlias``.  Tests for typing were also updated to
not subclass things like ``Callable[..., T]`` as that is not a valid base
class.  Finally, both types no longer validate their ``argtypes``, in
``Callable[[argtypes], resulttype]`` to prepare for :pep:`612`.  Patch by
Ken Jin.

..

.. bpo: 43102
.. date: 2021-02-03-22-55-27
.. nonce: TSlZ6J
.. section: Library

The namedtuple __new__ method had its __builtins__ set to None instead of an
actual dictionary.  This created problems for introspection tools.

..

.. bpo: 43108
.. date: 2021-02-02-20-23-31
.. nonce: lqcCZ6
.. section: Library

Fixed a reference leak in the :mod:`curses` module. Patch by Pablo Galindo

..

.. bpo: 42944
.. date: 2021-01-18-10-41-44
.. nonce: RrONvy
.. section: Library

Fix ``random.Random.sample`` when ``counts`` argument is not ``None``.

..

.. bpo: 42931
.. date: 2021-01-15-00-23-50
.. nonce: QD6U2B
.. section: Library

Add :func:`randbytes` to ``random.__all__``.

..

.. bpo: 42780
.. date: 2021-01-08-15-49-20
.. nonce: rtqi6B
.. section: Library

Fix os.set_inheritable() for O_PATH file descriptors on Linux.

..

.. bpo: 42851
.. date: 2021-01-07-11-44-22
.. nonce: uyQFyd
.. section: Library

remove __init_subclass__ support for Enum members

..

.. bpo: 41748
.. date: 2021-01-05-21-26-29
.. nonce: KdC0w3
.. section: Library

Fix HTMLParser parsing rules for element attributes containing commas with
spaces. Patch by Karl Dubost.

..

.. bpo: 42759
.. date: 2020-12-27-22-19-26
.. nonce: lGi_03
.. section: Library

Fixed equality comparison of :class:`tkinter.Variable` and
:class:`tkinter.font.Font`. Objects which belong to different Tcl
interpreters are now always different, even if they have the same name.

..

.. bpo: 42756
.. date: 2020-12-27-21-22-01
.. nonce: dHMPJ9
.. section: Library

Configure LMTP Unix-domain socket to use socket global default timeout when
a timeout is not explicitly provided.

..

.. bpo: 23328
.. date: 2020-12-27-18-47-01
.. nonce: _xqepZ
.. section: Library

Allow / character in username, password fields on _PROXY envars.

..

.. bpo: 42655
.. date: 2020-12-25-12-32-47
.. nonce: W5ytpV
.. section: Library

:mod:`subprocess` *extra_groups* is now correctly passed into setgroups()
system call.

..

.. bpo: 42727
.. date: 2020-12-23-19-43-06
.. nonce: WH3ODh
.. section: Library

``EnumMeta.__prepare__`` now accepts ``**kwds`` to properly support
``__init_subclass__``

..

.. bpo: 42681
.. date: 2020-12-20-22-50-15
.. nonce: lDO6jb
.. section: Library

Fixed range checks for color and pair numbers in :mod:`curses`.

..

.. bpo: 37961
.. date: 2020-12-16-16-16-33
.. nonce: jrESEq
.. section: Library

Fix crash in :func:`tracemalloc.Traceback.__repr__` (regressed in Python
3.9).

..

.. bpo: 42630
.. date: 2020-12-15-17-51-27
.. nonce: jf4jBl
.. section: Library

:mod:`tkinter` functions and constructors which need a default root window
raise now :exc:`RuntimeError` with descriptive message instead of obscure
:exc:`AttributeError` or :exc:`NameError` if it is not created yet or cannot
be created automatically.

..

.. bpo: 42644
.. date: 2020-12-15-10-00-04
.. nonce: XgLCNx
.. section: Library

`logging.disable` will now validate the types and value of its parameter. It
also now accepts strings representing the levels (as does `loging.setLevel`)
instead of only the numerical values.

..

.. bpo: 36541
.. date: 2020-12-14-08-23-57
.. nonce: qdEtZv
.. section: Library

Fixed lib2to3.pgen2 to be able to parse PEP-570 positional only argument
syntax.

..

.. bpo: 42517
.. date: 2020-12-09-10-59-16
.. nonce: FKEVcZ
.. section: Library

Enum: private names will raise a DeprecationWarning; in 3.10 they will
become normal attributes

..

.. bpo: 42678
.. date: 2020-12-08-22-43-35
.. nonce: ba9ktU
.. section: Library

`Enum`: call `__init_subclass__` after members have been added

..

.. 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: 42388
.. date: 2020-11-22-11-22-28
.. nonce: LMgM6B
.. section: Library

Fix subprocess.check_output(..., input=None) behavior when text=True to be
consistent with that of the documentation and universal_newlines=True.

..

.. bpo: 34463
.. date: 2020-11-20-19-00-27
.. nonce: aJcm56
.. section: Library

Fixed discrepancy between :mod:`traceback` and the interpreter in formatting
of SyntaxError with lineno not set (:mod:`traceback` was changed to match
interpreter).

..

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

subprocess module update for DragonFlyBSD support.

..

.. bpo: 42384
.. date: 2020-11-17-14-32-39
.. nonce: 1ZnQSn
.. section: Library

Make pdb populate sys.path[0] exactly the same as regular python execution.

..

.. bpo: 42383
.. date: 2020-11-17-14-30-12
.. nonce: ubl0Y_
.. section: Library

Fix pdb: previously pdb would fail to restart the debugging target if it was
specified using a relative path and the current directory changed.

..

.. 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: 42163
.. date: 2020-10-29-09-22-56
.. nonce: O4VcCY
.. section: Library

Restore compatibility for ``uname_result`` around deepcopy and _replace.

..

.. 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: 42059
.. date: 2020-10-17-12-42-08
.. nonce: ZGMZ3D
.. section: Library

:class:`typing.TypedDict` types created using the alternative call-style
syntax now correctly respect the ``total`` keyword argument when setting
their ``__required_keys__`` and ``__optional_keys__`` class attributes.

..

.. bpo: 39101
.. date: 2020-10-11-21-43-03
.. nonce: -I49Pm
.. section: Library

Fixed tests using IsolatedAsyncioTestCase from hanging on BaseExceptions.

..

.. bpo: 42005
.. date: 2020-10-11-13-48-03
.. nonce: Jq6Az-
.. section: Library

Fix CLI of :mod:`cProfile` and :mod:`profile` to catch
:exc:`BrokenPipeError`.

..

.. bpo: 41907
.. date: 2020-10-02-10-19-49
.. nonce: wiIEsz
.. section: Library

fix `format()` behavior for `IntFlag`

..

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

Enum: fix regression involving inheriting a multiply-inherited enum

..

.. bpo: 41891
.. date: 2020-09-30-13-35-29
.. nonce: pNAeYI
.. section: Library

Ensure asyncio.wait_for waits for task completion

..

.. bpo: 41604
.. date: 2020-08-21-15-24-14
.. nonce: rTXleO
.. section: Library

Don't decrement the reference count of the previous user_ptr when
set_panel_userptr fails.

..

.. bpo: 40219
.. date: 2020-07-13-19-43-11
.. nonce: MUoJEP
.. section: Library

Lowered :class:`tkinter.ttk.LabeledScale` dummy widget to prevent hiding
part of the content label.

..

.. bpo: 40084
.. date: 2020-03-29-21-32-00
.. nonce: MCYwcv
.. section: Library

Fix ``Enum.__dir__``: dir(Enum.member) now includes attributes as well as
methods.

..

.. bpo: 39068
.. date: 2019-12-16-17-55-31
.. nonce: Ti3f9P
.. section: Library

Fix initialization race condition in :func:`a85encode` and :func:`b85encode`
in :mod:`base64`. Patch by Brandon Stansbury.

..

.. bpo: 33289
.. date: 2018-04-23-13-44-10
.. nonce: anBnUr
.. section: Library

Correct call to :mod:`tkinter.colorchooser` to return RGB triplet of ints
instead of floats.  Patch by Cheryl Sabella.

..

.. bpo: 40304
.. date: 2021-01-20-23-03-49
.. nonce: -LK7Ps
.. section: Documentation

Fix doc for type(name, bases, dict).  Patch by Boris Verkhovskiy and Éric
Araujo.

..

.. bpo: 42811
.. date: 2021-01-07-12-08-59
.. nonce: ePF7EC
.. section: Documentation

Updated importlib.utils.resolve_name() doc to use __spec__.parent instead of
__package__. (Thanks Yair Frid.)

..

.. bpo: 17140
.. date: 2020-12-16-21-06-16
.. nonce: 1leSEg
.. section: Documentation

Add documentation for the :class:`multiprocessing.pool.ThreadPool` class.

..

.. bpo: 42794
.. date: 2021-01-01-08-52-36
.. nonce: -7-XGz
.. section: Tests

Update test_nntplib to use offical group name of news.aioe.org for testing.
Patch by Dong-hee Na.

..

.. bpo: 40810
.. date: 2020-05-30-10-56-38
.. nonce: LPqDLQ
.. section: Tests

In :mod:`sqlite3`, fix ``CheckTraceCallbackContent`` for SQLite pre 3.7.15.

..

.. bpo: 43174
.. date: 2021-02-10-14-11-53
.. nonce: F9zwXQ
.. section: Build

Windows build now uses ``/utf-8`` compiler option.

..

.. bpo: 42692
.. date: 2021-01-04-05-07-30
.. nonce: OO11SN
.. section: Build

Fix __builtin_available check on older compilers. Patch by Joshua Root.

..

.. bpo: 42604
.. date: 2020-12-20-02-35-28
.. nonce: gRd89w
.. section: Build

Now all platforms use a value for the "EXT_SUFFIX" build variable derived
from SOABI (for instance in freeBSD, "EXT_SUFFIX" is now ".cpython-310d.so"
instead of ".so"). Previosuly only Linux, Mac and VxWorks were using a value
for "EXT_SUFFIX" that included "SOABI".

..

.. bpo: 42598
.. date: 2020-12-13-14-43-10
.. nonce: 7ipr5H
.. section: Build

Fix implicit function declarations in configure which could have resulted in
incorrect configuration checks.  Patch contributed by Joshua Root.

..

.. bpo: 29076
.. date: 2020-02-28-14-33-15
.. nonce: Gtixi5
.. section: Build

Add fish shell support to macOS installer.

..

.. bpo: 41837
.. date: 2021-01-05-20-36-40
.. nonce: bmS7vB
.. section: Windows

Updated Windows installer to include OpenSSL 1.1.1i

..

.. bpo: 42584
.. date: 2020-12-07-11-40-52
.. nonce: AsYnVX
.. section: Windows

Upgrade Windows installer to use SQLite 3.34.0.

..

.. bpo: 42504
.. date: 2021-01-26-14-36-11
.. nonce: ZxWt71
.. section: macOS

Ensure that the value of
sysconfig.get_config_var('MACOSX_DEPLOYMENT_TARGET') is always a string,
even in when the value is parsable as an integer.

..

.. bpo: 42361
.. date: 2021-01-04-01-17-17
.. nonce: eolZAi
.. section: macOS

Update macOS installer build to use Tcl/Tk 8.6.11 (rc2, expected to be final
release).

..

.. bpo: 41837
.. date: 2021-01-04-00-48-08
.. nonce: dX-unJ
.. section: macOS

Update macOS installer build to use OpenSSL 1.1.1i.

..

.. bpo: 42584
.. date: 2020-12-07-11-37-35
.. nonce: LygmqQ
.. section: macOS

Update macOS installer to use SQLite 3.34.0.

..

.. bpo: 43008
.. date: 2021-01-26-18-12-17
.. nonce: mbQUc7
.. section: IDLE

Make IDLE invoke :func:`sys.excepthook` in normal, 2-process mode. Patch by
Ken Hilton.

..

.. bpo: 33065
.. date: 2021-01-10-01-25-43
.. nonce: zmyHYJ
.. section: IDLE

Fix problem debugging user classes with __repr__ method.

..

.. bpo: 23544
.. date: 2019-11-14-23-41-07
.. nonce: 3etemb
.. section: IDLE

Disable Debug=>Stack Viewer when user code is running or Debugger is active,
to prevent hang or crash.  Patch by Zackery Spytz.

..

.. bpo: 32631
.. date: 2019-06-30-20-31-09
.. nonce: e7_4BG
.. section: IDLE

Finish zzdummy example extension module: make menu entries work; add
docstrings and tests with 100% coverage.

..

.. bpo: 42726
.. date: 2020-12-23-19-42-11
.. nonce: a5EkTv
.. section: Tools/Demos

Fixed Python 3 compatibility issue with gdb/libpython.py handling of
attribute dictionaries.

..

.. bpo: 42613
.. date: 2020-12-16-09-10-32
.. nonce: J-jnm5
.. section: Tools/Demos

Fix ``freeze.py`` tool to use the prope config and library directories.
Patch by Victor Stinner.

..

.. bpo: 43030
.. date: 2021-01-27-10-27-47
.. nonce: loDcD_
.. section: C API

Fixed a compiler warning in :c:func:`Py_UNICODE_ISSPACE()` on platforms with
signed ``wchar_t``.

..

.. bpo: 42591
.. date: 2020-12-10-10-43-03
.. nonce: CXNY8G
.. section: C API

Export the :c:func:`Py_FrozenMain` function: fix a Python 3.9.0 regression.
Python 3.9 uses ``-fvisibility=hidden`` and the function was not exported
explicitly and so not exported.

..

.. bpo: 40052
.. date: 2020-03-24-09-27-10
.. nonce: 27P2KG
.. section: C API

Fix an alignment build warning/error in function
``PyVectorcall_Function()``. Patch by Andreas Schneider, Antoine Pitrou and
Petr Viktorin.