3.10.0a3 - Cpython — ContextQMD

.. 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 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.