3.9.0a2 - Cpython — ContextQMD

.. bpo: 38945 .. date: 2019-12-01-22-44-40 .. nonce: ztmNXc .. release date: 2019-12-18 .. section: Security

Newline characters have been escaped when performing uu encoding to prevent them from overflowing into to content section of the encoded file. This prevents malicious or accidental modification of data during the decoding process.

.. bpo: 37228 .. date: 2019-11-21-21-36-54 .. nonce: yBZnFG .. section: Security

Due to significant security concerns, the reuse_address parameter of :meth:asyncio.loop.create_datagram_endpoint is no longer supported. This is because of the behavior of SO_REUSEADDR in UDP. For more details, see the documentation for loop.create_datagram_endpoint(). (Contributed by Kyle Stanley, Antoine Pitrou, and Yury Selivanov in :issue:37228.)

.. bpo: 38804 .. date: 2019-11-15-00-54-42 .. nonce: vjbM8V .. section: Security

Fixes a ReDoS vulnerability in :mod:http.cookiejar. Patch by Ben Caller.

.. bpo: 39028 .. date: 2019-12-17-23-20-51 .. nonce: SND4TB .. section: Core and Builtins

Slightly improve the speed of keyword argument parsing with many kwargs by strengthening the assumption that kwargs are interned strings.

.. bpo: 39080 .. date: 2019-12-17-21-45-36 .. nonce: OrxEVS .. section: Core and Builtins

Fix the value of end_col_offset for Starred Expression AST nodes when they are among the elements in the args attribute of Call AST nodes.

.. bpo: 39031 .. date: 2019-12-12-21-05-43 .. nonce: imlCYZ .. section: Core and Builtins

When parsing an "elif" node, lineno and col_offset of the node now point to the "elif" keyword and not to its condition, making it consistent with the "if" node. Patch by Lysandros Nikolaou.

.. bpo: 20443 .. date: 2019-12-09-17-05-53 .. nonce: 8OyT5P .. section: Core and Builtins

In Python 3.9.0a1, sys.argv[0] was made an absolute path if a filename was specified on the command line. Revert this change, since most users expect sys.argv to be unmodified.

.. bpo: 39008 .. date: 2019-12-09-10-38-51 .. nonce: Rrp6f1 .. section: Core and Builtins

:c:func:PySys_Audit now requires Py_ssize_t to be used for size arguments in the format string, regardless of whether PY_SSIZE_T_CLEAN was defined at include time.

.. bpo: 38673 .. date: 2019-12-01-00-17-44 .. nonce: K_Tze- .. section: Core and Builtins

In REPL mode, don't switch to PS2 if the line starts with comment or whitespace. Based on work by Batuhan Taşkaya.

.. bpo: 38922 .. date: 2019-11-26-12-20-34 .. nonce: i6ja-i .. section: Core and Builtins

Calling replace on a code object now raises the code.__new__ audit event.

.. bpo: 38920 .. date: 2019-11-26-09-16-47 .. nonce: Vx__sT .. section: Core and Builtins

Add audit hooks for when :func:sys.excepthook and :func:sys.unraisablehook are invoked.

.. bpo: 38892 .. date: 2019-11-22-22-18-50 .. nonce: LS586s .. section: Core and Builtins

Improve documentation for audit events table and functions.

.. bpo: 38852 .. date: 2019-11-22-09-55-21 .. nonce: y7oPEa .. section: Core and Builtins

Set the thread stack size to 8 Mb for debug builds on android platforms.

.. bpo: 38858 .. date: 2019-11-21-09-02-49 .. nonce: bDLH04 .. section: Core and Builtins

Each Python subinterpreter now has its own "small integer singletons": numbers in [-5; 257] range. It is no longer possible to change the number of small integers at build time by overriding NSMALLNEGINTS and NSMALLPOSINTS macros: macros should now be modified manually in pycore_pystate.h header file.

.. bpo: 36854 .. date: 2019-11-20-12-01-37 .. nonce: Zga_md .. section: Core and Builtins

The garbage collector state becomes per interpreter (PyInterpreterState.gc), rather than being global (_PyRuntimeState.gc).

.. bpo: 38835 .. date: 2019-11-18-16-37-49 .. nonce: -U4se1 .. section: Core and Builtins

The PyFPE_START_PROTECT() and PyFPE_END_PROTECT() macros are empty: they have been doing nothing for the last year, so stop using them.

.. bpo: 38328 .. date: 2019-11-11-23-44-15 .. nonce: IFrrjq .. section: Core and Builtins

Sped up the creation time of constant :class:list and :class:set displays. Patch by Brandt Bucher.

.. bpo: 38707 .. date: 2019-11-08-00-36-10 .. nonce: SZL036 .. section: Core and Builtins

MainThread.native_id is now correctly reset in child processes spawned using :class:multiprocessing.Process, instead of retaining the parent's value.

.. bpo: 38629 .. date: 2019-10-29-17-11-15 .. nonce: 3qinhF .. section: Core and Builtins

Added __floor__ and __ceil__ methods to float object. Patch by Batuhan Taşkaya.

.. bpo: 27145 .. date: 2019-09-06-16-40-12 .. nonce: njuCXU .. section: Core and Builtins

int + int and int - int operators can now return small integer singletons. Patch by hongweipeng.

.. bpo: 38021 .. date: 2019-09-03-19-16-57 .. nonce: KnUhdB .. section: Core and Builtins

Provide a platform tag for AIX that is sufficient for PEP425 binary distribution identification. Patch by Michael Felt.

.. bpo: 35409 .. date: 2019-07-13-18-01-13 .. nonce: ozbcsR .. section: Core and Builtins

Ignore GeneratorExit exceptions when throwing an exception into the aclose coroutine of an asynchronous generator.

.. bpo: 33387 .. date: 2018-03-13-14-46-03 .. nonce: v821M7 .. section: Core and Builtins

Removed WITH_CLEANUP_START, WITH_CLEANUP_FINISH, BEGIN_FINALLY, END_FINALLY, CALL_FINALLY and POP_FINALLY bytecodes. Replaced with RERAISE and WITH_EXCEPT_START bytecodes. The compiler now generates different code for exceptional and non-exceptional branches for 'with' and 'try-except' statements. For 'try-finally' statements the 'finally' block is replicated for each exit from the 'try' body.

.. bpo: 39033 .. date: 2019-12-13-18-54-49 .. nonce: cepuyD .. section: Library

Fix :exc:NameError in :mod:zipimport. Patch by Karthikeyan Singaravelan.

.. bpo: 39022 .. date: 2019-12-10-23-34-48 .. nonce: QDtIxI .. section: Library

Update importlib.metadata to include improvements from importlib_metadata 1.3 including better serialization of EntryPoints and improved documentation for custom finders.

.. bpo: 39006 .. date: 2019-12-09-14-40-09 .. nonce: v4VsPg .. section: Library

Fix asyncio when the ssl module is missing: only check for ssl.SSLSocket instance if the ssl module is available.

.. bpo: 38708 .. date: 2019-12-07-22-25-39 .. nonce: rZTUfk .. section: Library

Fix a potential IndexError in email parser when parsing an empty msg-id.

.. bpo: 38698 .. date: 2019-12-07-21-49-50 .. nonce: HxoSym .. section: Library

Add a new InvalidMessageID token to email parser to represent invalid Message-ID headers. Also, add defects when there is remaining value after parsing the header.

.. bpo: 38994 .. date: 2019-12-07-18-58-44 .. nonce: IJYhz_ .. section: Library

Implement __class_getitem__ for os.PathLike, pathlib.Path.

.. bpo: 38979 .. date: 2019-12-07-16-32-42 .. nonce: q0sIHy .. section: Library

Return class from ContextVar.__class_getitem__ to simplify subclassing.

.. bpo: 38978 .. date: 2019-12-07-13-40-52 .. nonce: R3gHZI .. section: Library

Implement __class_getitem__ on asyncio objects (Future, Task, Queue). Patch by Batuhan Taskaya.

.. bpo: 38916 .. date: 2019-12-06-18-47-56 .. nonce: K-raU8 .. section: Library

:class:array.array: Remove tostring() and fromstring() methods. They were aliases to tobytes() and frombytes(), deprecated since Python 3.2.

.. bpo: 38986 .. date: 2019-12-06-15-11-42 .. nonce: bg6iZt .. section: Library

Make repr of C accelerated TaskWakeupMethWrapper the same as of pure Python version.

.. bpo: 38982 .. date: 2019-12-05-18-21-26 .. nonce: W3u-03 .. section: Library

Fix asyncio PidfdChildWatcher: handle waitpid() error. If waitpid() is called elsewhere, waitpid() call fails with :exc:ChildProcessError: use return code 255 in this case, and log a warning. It ensures that the pidfd file descriptor is closed if this error occurs.

.. bpo: 38529 .. date: 2019-12-05-16-13-25 .. nonce: yvQgx3 .. section: Library

Drop too noisy asyncio warning about deletion of a stream without explicit .close() call.

.. bpo: 27413 .. date: 2019-12-05-02-02-58 .. nonce: 212Th2 .. section: Library

Added ability to pass through ensure_ascii options to json.dumps in the json.tool command-line interface.

.. bpo: 38634 .. date: 2019-12-04-15-56-28 .. nonce: pq0ZWa .. section: Library

The :mod:readline module now detects if Python is linked to libedit at runtime on all platforms. Previously, the check was only done on macOS.

.. bpo: 33684 .. date: 2019-12-04-15-28-40 .. nonce: QeSmQP .. section: Library

Fix json.tool failed to read a JSON file with non-ASCII characters when locale encoding is not UTF-8.

.. bpo: 38698 .. date: 2019-12-02-10-35-19 .. nonce: WZnAPQ .. section: Library

Prevent UnboundLocalError to pop up in parse_message_id.

parse_message_id() was improperly using a token defined inside an exception handler, which was raising UnboundLocalError on parsing an invalid value. Patch by Claudiu Popa.

.. bpo: 38927 .. date: 2019-11-27-17-47-00 .. nonce: qT7xKY .. section: Library

Use python -m pip instead of pip to upgrade dependencies in venv.

.. bpo: 26730 .. date: 2019-11-27-16-30-02 .. nonce: 56cdBn .. section: Library

Fix SpooledTemporaryFile.rollover() might corrupt the file when it is in text mode. Patch by Serhiy Storchaka.

.. bpo: 38881 .. date: 2019-11-22-20-03-46 .. nonce: 7HV1Q0 .. section: Library

random.choices() now raises a ValueError when all the weights are zero.

.. bpo: 38876 .. date: 2019-11-22-10-58-58 .. nonce: qqy1Vp .. section: Library

Raise pickle.UnpicklingError when loading an item from memo for invalid input.

The previous code was raising a KeyError for both the Python and C implementation. This was caused by the specified index of an invalid input which did not exist in the memo structure, where the pickle stores what objects it has seen. The malformed input would have caused either a BINGET or LONG_BINGET load from the memo, leading to a KeyError as the determined index was bogus. Patch by Claudiu Popa.

.. bpo: 38688 .. date: 2019-11-22-10-45-03 .. nonce: iKx23z .. section: Library

Calling func:shutil.copytree to copy a directory tree from one directory to another subdirectory resulted in an endless loop and a RecursionError. A fix was added to consume an iterator and create the list of the entries to be copied, avoiding the recursion for newly created directories. Patch by Bruno P. Kinoshita.

.. bpo: 38863 .. date: 2019-11-21-16-30-00 .. nonce: RkdTjf .. section: Library

Improve :func:is_cgi function in :mod:http.server, which enables processing the case that cgi directory is a child of another directory other than root.

.. bpo: 37838 .. date: 2019-11-21-11-39-17 .. nonce: lRFcEC .. section: Library

:meth:typing.get_type_hints properly handles functions decorated with :meth:functools.wraps.

.. bpo: 38870 .. date: 2019-11-20-22-43-48 .. nonce: rLVZEv .. section: Library

Expose :func:ast.unparse as a function of the :mod:ast module that can be used to unparse an :class:ast.AST object and produce a string with code that would produce an equivalent :class:ast.AST object when parsed. Patch by Pablo Galindo and Batuhan Taskaya.

.. bpo: 38859 .. date: 2019-11-19-16-30-46 .. nonce: AZUzL8 .. section: Library

AsyncMock now returns StopAsyncIteration on the exhaustion of a side_effects iterable. Since PEP-479 its Impossible to raise a StopIteration exception from a coroutine.

.. bpo: 38857 .. date: 2019-11-19-16-28-25 .. nonce: YPUkU9 .. section: Library

AsyncMock fix for return values that are awaitable types. This also covers side_effect iterable values that happened to be awaitable, and wraps callables that return an awaitable type. Before these awaitables were being awaited instead of being returned as is.

.. bpo: 38834 .. date: 2019-11-18-17-08-23 .. nonce: abcdef .. section: Library

:class:typing.TypedDict subclasses now track which keys are optional using the __required_keys__ and __optional_keys__ attributes, to enable runtime validation by downstream projects. Patch by Zac Hatfield-Dodds.

.. bpo: 38821 .. date: 2019-11-16-23-26-25 .. nonce: -albNN .. section: Library

Fix unhandled exceptions in :mod:argparse when internationalizing error messages for arguments with nargs set to special (non-integer) values. Patch by Federico Bond.

.. bpo: 38820 .. date: 2019-11-16-16-09-07 .. nonce: ivhUSV .. section: Library

Make Python compatible with OpenSSL 3.0.0. :func:ssl.SSLSocket.getpeercert no longer returns IPv6 addresses with a trailing new line.

.. bpo: 38811 .. date: 2019-11-15-18-06-04 .. nonce: AmdQ6M .. section: Library

Fix an unhandled exception in :mod:pathlib when :meth:os.link is missing. Patch by Toke Høiland-Jørgensen.

.. bpo: 38686 .. date: 2019-11-06-15-26-15 .. nonce: HNFBce .. section: Library

Added support for multiple qop values in :class:urllib.request.AbstractDigestAuthHandler.

.. bpo: 38712 .. date: 2019-11-05-21-10-12 .. nonce: ezJ0TP .. section: Library

Add the Linux-specific :func:signal.pidfd_send_signal function, which allows sending a signal to a process identified by a file descriptor rather than a pid.

.. bpo: 38348 .. date: 2019-10-02-18-15-28 .. nonce: _-5eq2 .. section: Library

Add -i and --indent (indentation level), and --no-type-comments (type comments) command line options to ast parsing tool.

.. bpo: 37523 .. date: 2019-10-02-02-55-37 .. nonce: GguwJ6 .. section: Library

Change :class:zipfile.ZipExtFile to raise ValueError when trying to access the underlying file object after it has been closed. This new behavior is consistent with how accessing closed files is handled in other parts of Python.

.. bpo: 38045 .. date: 2019-09-30-12-09-41 .. nonce: VDRtd3 .. section: Library

Improve the performance of :func:enum._decompose in :mod:enum. Patch by hongweipeng.

.. bpo: 36820 .. date: 2019-05-06-15-34-17 .. nonce: Eh5mIB .. section: Library

Break cycle generated when saving an exception in socket.py, codeop.py and dyld.py as they keep alive not only the exception but user objects through the __traceback__ attribute. Patch by Mario Corchero.

.. bpo: 36406 .. date: 2019-03-24-12-12-27 .. nonce: mCEkOl .. section: Library

Handle namespace packages in :mod:doctest. Patch by Karthikeyan Singaravelan.

.. bpo: 34776 .. date: 2018-09-23-14-24-37 .. nonce: 1SrQe3 .. section: Library

Fix dataclasses to support forward references in type annotations

.. bpo: 20928 .. date: 2018-03-30-16-18-12 .. nonce: ieXu6I .. section: Library

ElementTree supports recursive XInclude processing. Patch by Stefan Behnel.

.. bpo: 29636 .. date: 2018-02-22-11-24-33 .. nonce: ogGRE2 .. section: Library

Add whitespace options for formatting JSON with the json.tool CLI. The following mutually exclusive options are now supported: --indent for setting the indent level in spaces; --tab for indenting with tabs; --no-indent for suppressing newlines; and --compact for suppressing all whitespace. The default behavior remains the same as --indent=4.

.. bpo: 38928 .. date: 2019-11-27-17-51-27 .. nonce: AfgvfO .. section: Documentation

Correct when venv's upgrade_dependencies() and --upgrade-deps are added.

.. bpo: 38899 .. date: 2019-11-22-15-57-29 .. nonce: 4aYPW2 .. section: Documentation

Update documentation to state that to activate virtual environments under fish one should use source, not . as documented at https://fishshell.com/docs/current/cmds/source.html.

.. bpo: 22377 .. date: 2019-10-01-10-53-46 .. nonce: 5ni-iC .. section: Documentation

Improves documentation of the values that :meth:datetime.datetime.strptime accepts for %Z. Patch by Karl Dubost.

.. bpo: 38546 .. date: 2019-12-18-14-52-08 .. nonce: 2kxNuM .. section: Tests

Fix test_ressources_gced_in_workers() of test_concurrent_futures: explicitly stop the manager to prevent leaking a child process running in the background after the test completes.

.. bpo: 38546 .. date: 2019-12-17-15-27-07 .. nonce: 82JwN2 .. section: Tests

Multiprocessing and concurrent.futures tests now stop the resource tracker process when tests complete.

.. bpo: 38614 .. date: 2019-12-10-14-26-23 .. nonce: 89JpNh .. section: Tests

Replace hardcoded timeout constants in tests with new :mod:test.support constants: :data:~test.support.LOOPBACK_TIMEOUT, :data:~test.support.INTERNET_TIMEOUT, :data:~test.support.SHORT_TIMEOUT and :data:~test.support.LONG_TIMEOUT. It becomes easier to adjust these four timeout constants for all tests at once, rather than having to adjust every single test file.

.. bpo: 38547 .. date: 2019-12-09-11-32-34 .. nonce: Juw54e .. section: Tests

Fix test_pty: if the process is the session leader, closing the master file descriptor raises a SIGHUP signal: simply ignore SIGHUP when running the tests.

.. bpo: 38992 .. date: 2019-12-08-15-11-06 .. nonce: cVoHOZ .. section: Tests

Fix a test for :func:math.fsum that was failing due to constant folding.

.. bpo: 38991 .. date: 2019-12-07-00-52-09 .. nonce: JE3_o- .. section: Tests

:mod:test.support: :func:~test.support.run_python_until_end, :func:~test.support.assert_python_ok and :func:~test.support.assert_python_failure functions no longer strip whitespaces from stderr. Remove test.support.strip_python_stderr() function.

.. bpo: 38965 .. date: 2019-12-04-17-08-55 .. nonce: yqax3m .. section: Tests

Fix test_faulthandler on GCC 10. Use the "volatile" keyword in faulthandler._stack_overflow() to prevent tail call optimization on any compiler, rather than relying on compiler specific pragma.

.. bpo: 38875 .. date: 2019-11-21-09-11-06 .. nonce: wSZJal .. section: Tests

test_capi: trashcan tests now require the test "cpu" resource.

.. bpo: 38841 .. date: 2019-11-20-16-08-19 .. nonce: 5F5Lbw .. section: Tests

Skip asyncio test_create_datagram_endpoint_existing_sock_unix on platforms lacking a functional bind() for named unix domain sockets.

.. bpo: 38692 .. date: 2019-11-20-15-42-06 .. nonce: aqAvyF .. section: Tests

Skip the test_posix.test_pidfd_open() test if os.pidfd_open() fails with a :exc:PermissionError. This situation can happen in a Linux sandbox using a syscall whitelist which doesn't allow the pidfd_open() syscall yet.

.. bpo: 38839 .. date: 2019-11-18-22-10-55 .. nonce: di6tXv .. section: Tests

Fix some unused functions in tests. Patch by Adam Johnson.

.. bpo: 38669 .. date: 2019-11-04-02-54-16 .. nonce: pazXZ8 .. section: Tests

Raise :exc:TypeError when passing target as a string with :meth:unittest.mock.patch.object.

.. bpo: 37957 .. date: 2019-10-30-00-01-43 .. nonce: X1r78F .. section: Tests

test.regrtest now can receive a list of test patterns to ignore (using the -i/--ignore argument) or a file with a list of patterns to ignore (using the --ignore-file argument). Patch by Pablo Galindo.

.. bpo: 37404 .. date: 2019-12-01-21-45-24 .. nonce: cNsA7S .. section: Build

:mod:asyncio now raises :exc:TypeError when calling incompatible methods with an :class:ssl.SSLSocket socket. Patch by Ido Michael.

.. bpo: 36500 .. date: 2019-04-02-01-59-26 .. nonce: fyG6_U .. section: Build

Added an optional "regen" project to the Visual Studio solution that will regenerate all grammar, tokens, and opcodes.

.. bpo: 39007 .. date: 2019-12-09-10-40-34 .. nonce: vtarxo .. section: Windows

Add auditing events to functions in :mod:winreg.

.. bpo: 33125 .. date: 2019-11-14-08-57-50 .. nonce: EN5MWS .. section: Windows

Add support for building and releasing Windows ARM64 packages.

.. bpo: 37931 .. date: 2019-08-23-12-14-34 .. nonce: goYgQj .. section: macOS

Fixed a crash on OSX dynamic builds that occurred when re-initializing the posix module after a Py_Finalize if the environment had changed since the previous import posix. Patch by Benoît Hudson.

.. bpo: 38944 .. date: 2019-11-30-12-10-36 .. nonce: _3xjKG .. section: IDLE

Escape key now closes IDLE completion windows. Patch by Johnny Najera.

.. bpo: 38943 .. date: 2019-11-29-23-44-11 .. nonce: 8pUKKs .. section: IDLE

Fix IDLE autocomplete windows not always appearing on some systems. Patch by Johnny Najera.

.. bpo: 38862 .. date: 2019-11-23-21-50-57 .. nonce: KQ9A0m .. section: IDLE

'Strip Trailing Whitespace' on the Format menu removes extra newlines at the end of non-shell files.

.. bpo: 38636 .. date: 2019-10-30-22-11-16 .. nonce: hUhDeB .. section: IDLE

Fix IDLE Format menu tab toggle and file indent width. These functions (default shortcuts Alt-T and Alt-U) were mistakenly disabled in 3.7.5 and 3.8.0.

.. bpo: 38896 .. date: 2019-11-22-19-43-43 .. nonce: 6wvNMJ .. section: C API

Remove PyUnicode_ClearFreeList() function: the Unicode free list has been removed in Python 3.3.

.. bpo: 37340 .. date: 2019-11-20-11-08-06 .. nonce: JBQJMS .. section: C API

Remove PyMethod_ClearFreeList() and PyCFunction_ClearFreeList() functions: the free lists of bound method objects have been removed.

.. bpo: 38835 .. date: 2019-11-18-15-38-23 .. nonce: II8Szd .. section: C API

Exclude PyFPE_START_PROTECT() and PyFPE_END_PROTECT() macros of pyfpe.h from Py_LIMITED_API (stable API).