3.7.0a4 - Cpython — ContextQMD

.. bpo: 31975 .. date: 2018-01-05-20-54-27 .. nonce: AmftlU .. release date: 2018-01-08 .. section: Core and Builtins

The default warning filter list now starts with a "default::DeprecationWarning:main" entry, so deprecation warnings are once again shown by default in single-file scripts and at the interactive prompt.

.. bpo: 32226 .. date: 2018-01-04-15-06-15 .. nonce: 7cAvRG .. section: Core and Builtins

__class_getitem__ is now an automatic class method.

.. bpo: 32399 .. date: 2017-12-22-13-38-17 .. nonce: wlH12z .. section: Core and Builtins

Add AIX uuid library support for RFC4122 using uuid_create() in libc.a

.. bpo: 32390 .. date: 2017-12-22-13-28-07 .. nonce: QPj083 .. section: Core and Builtins

Fix the compilation failure on AIX after the f_fsid field has been added to the object returned by os.statvfs() (issue #32143). Original patch by Michael Felt.

.. bpo: 32379 .. date: 2017-12-19-21-14-41 .. nonce: B7mOmI .. section: Core and Builtins

Make MRO computation faster when a class inherits from a single base.

.. bpo: 32259 .. date: 2017-12-16-14-30-21 .. nonce: GoOJiX .. section: Core and Builtins

The error message of a TypeError raised when unpack non-iterable is now more specific.

.. bpo: 27169 .. date: 2017-12-15-11-50-06 .. nonce: VO84fQ .. section: Core and Builtins

The __debug__ constant is now optimized out at compile time. This fixes also bpo-22091.

.. bpo: 32329 .. date: 2017-12-15-00-13-04 .. nonce: q47IN2 .. section: Core and Builtins

The :option:-R option now turns on hash randomization when the :envvar:PYTHONHASHSEED environment variable is set to 0. Previously, the option was ignored. Moreover, sys.flags.hash_randomization is now properly set to 0 when hash randomization is turned off by PYTHONHASHSEED=0.

.. bpo: 30416 .. date: 2017-12-14-11-48-19 .. nonce: hlHo_9 .. section: Core and Builtins

The optimizer is now protected from spending much time doing complex calculations and consuming much memory for creating large constants in constant folding. Increased limits for constants that can be produced in constant folding.

.. bpo: 32282 .. date: 2017-12-12-14-02-28 .. nonce: xFVMTn .. section: Core and Builtins

Fix an unnecessary ifdef in the include of VersionHelpers.h in socketmodule on Windows.

.. bpo: 30579 .. date: 2017-12-11-01-52-42 .. nonce: X6cEzf .. section: Core and Builtins

Implement TracebackType.new to allow Python-level creation of traceback objects, and make TracebackType.tb_next mutable.

.. bpo: 32260 .. date: 2017-12-09-11-03-51 .. nonce: 1DAO-p .. section: Core and Builtins

Don't byte swap the input keys to the SipHash algorithm on big-endian platforms. This should ensure siphash gives consistent results across platforms.

.. bpo: 31506 .. date: 2017-12-07-23-44-29 .. nonce: j1U2fU .. section: Core and Builtins

Improve the error message logic for object.new and object.init. Patch by Sanyam Khurana.

.. bpo: 20361 .. date: 2017-12-07-17-22-30 .. nonce: zQUmbi .. section: Core and Builtins

-b and -bb now inject 'default::BytesWarning' and error::BytesWarning entries into sys.warnoptions, ensuring that they take precedence over any other warning filters configured via the -W option or the PYTHONWARNINGS environment variable.

.. bpo: 32230 .. date: 2017-12-06-20-18-34 .. nonce: PgGQaB .. section: Core and Builtins

-X dev now injects a 'default' entry into sys.warnoptions, ensuring that it behaves identically to actually passing -Wdefault at the command line.

.. bpo: 29240 .. date: 2017-12-05-23-10-58 .. nonce: qpJP5l .. section: Core and Builtins

Add a new UTF-8 mode: implementation of the :pep:540.

.. bpo: 32226 .. date: 2017-12-05-21-42-58 .. nonce: G8fqb6 .. section: Core and Builtins

:pep:560: Add support for __mro_entries__ and __class_getitem__. Implemented by Ivan Levkivskyi.

.. bpo: 32225 .. date: 2017-12-05-21-33-47 .. nonce: ucKjvw .. section: Core and Builtins

:pep:562: Add support for module __getattr__ and __dir__. Implemented by Ivan Levkivskyi.

.. bpo: 31901 .. date: 2017-11-28-15-04-14 .. nonce: mDeCLK .. section: Core and Builtins

The atexit module now has its callback stored per interpreter.

.. bpo: 31650 .. date: 2017-11-26-14-38-44 .. nonce: JWf_Im .. section: Core and Builtins

Implement :pep:552 (Deterministic pycs). Python now supports invalidating bytecode cache files bashed on a source content hash rather than source last-modified time.

.. bpo: 29469 .. date: 2017-07-26-00-20-15 .. nonce: potmyI .. section: Core and Builtins

Move constant folding from bytecode layer to AST layer. Original patch by Eugene Toder.

.. bpo: 32506 .. date: 2018-01-07-11-32-42 .. nonce: MaT-zU .. section: Library

Now that dict is defined as keeping insertion order, drop OrderedDict and just use plain dict.

.. bpo: 32279 .. date: 2018-01-06-16-50-11 .. nonce: 1xOpU8 .. section: Library

Add params to dataclasses.make_dataclasses(): init, repr, eq, order, hash, and frozen. Pass them through to dataclass().

.. bpo: 32278 .. date: 2018-01-06-15-15-34 .. nonce: bGnGc0 .. section: Library

Make type information optional on dataclasses.make_dataclass(). If omitted, the string 'typing.Any' is used.

.. bpo: 32499 .. date: 2018-01-06-10-54-16 .. nonce: koyY-4 .. section: Library

Add dataclasses.is_dataclass(obj), which returns True if obj is a dataclass or an instance of one.

.. bpo: 32468 .. date: 2017-12-31-20-32-58 .. nonce: YBs__0 .. section: Library

Improve frame repr() to mention filename, code name and current line number.

.. bpo: 23749 .. date: 2017-12-29-00-44-42 .. nonce: QL1Cxd .. section: Library

asyncio: Implement loop.start_tls()

.. bpo: 32441 .. date: 2017-12-28-21-30-40 .. nonce: LqlboJ .. section: Library

Return the new file descriptor (i.e., the second argument) from os.dup2. Previously, None was always returned.

.. bpo: 32422 .. date: 2017-12-25-20-22-47 .. nonce: 5H3Wq2 .. section: Library

functools.lru_cache uses less memory (3 words for each cached key) and takes about 1/3 time for cyclic GC.

.. bpo: 31721 .. date: 2017-12-25-11-09-46 .. nonce: 5gM972 .. section: Library

Prevent Python crash from happening when Future._log_traceback is set to True manually. Now it can only be set to False, or a ValueError is raised.

.. bpo: 32415 .. date: 2017-12-23-12-45-00 .. nonce: YufXTU .. section: Library

asyncio: Add Task.get_loop() and Future.get_loop()

.. bpo: 26133 .. date: 2017-12-21-11-08-42 .. nonce: mt81QV .. section: Library

Don't unsubscribe signals in asyncio UNIX event loop on interpreter shutdown.

.. bpo: 32363 .. date: 2017-12-19-00-37-28 .. nonce: YTeGU0 .. section: Library

Make asyncio.Task.set_exception() and set_result() raise NotImplementedError. Task._step() and Future.await() raise proper exceptions when they are in an invalid state, instead of raising an AssertionError.

.. bpo: 32357 .. date: 2017-12-18-00-36-41 .. nonce: t1F3sn .. section: Library

Optimize asyncio.iscoroutine() and loop.create_task() for non-native coroutines (e.g. async/await compiled with Cython). 'loop.create_task(python_coroutine)' used to be 20% faster than 'loop.create_task(cython_coroutine)'. Now, the latter is as fast.

.. bpo: 32356 .. date: 2017-12-17-22-50-51 .. nonce: roZJpA .. section: Library

asyncio.transport.resume_reading() and pause_reading() are now idempotent. New transport.is_reading() method is added.

.. bpo: 32355 .. date: 2017-12-17-21-42-24 .. nonce: tbaTWA .. section: Library

Optimize asyncio.gather(); now up to 15% faster.

.. bpo: 32351 .. date: 2017-12-17-14-23-23 .. nonce: 95fh2K .. section: Library

Use fastpath in asyncio.sleep if delay<0 (2x boost)

.. bpo: 32348 .. date: 2017-12-16-18-50-57 .. nonce: 5j__he .. section: Library

Optimize asyncio.Future schedule/add/remove callback. The optimization shows 3-6% performance improvements of async/await code.

.. bpo: 32331 .. date: 2017-12-15-23-48-43 .. nonce: fIg1Uc .. section: Library

Fix socket.settimeout() and socket.setblocking() to keep socket.type as is. Fix socket.socket() constructor to reset any bit flags applied to socket's type. This change only affects OSes that have SOCK_NONBLOCK and/or SOCK_CLOEXEC.

.. bpo: 32248 .. date: 2017-12-15-15-34-12 .. nonce: zmO8G2 .. section: Library

Add :class:!importlib.abc.ResourceReader as an ABC for loaders to provide a unified API for reading resources contained within packages. Also add :mod:importlib.resources as the port of importlib_resources.

.. bpo: 32311 .. date: 2017-12-14-17-28-54 .. nonce: DL5Ytn .. section: Library

Implement asyncio.create_task(coro) shortcut

.. bpo: 32327 .. date: 2017-12-14-16-00-25 .. nonce: bbkSxA .. section: Library

Convert asyncio functions that were documented as coroutines to coroutines. Affected functions: loop.sock_sendall, loop.sock_recv, loop.sock_accept, loop.getaddrinfo, loop.getnameinfo.

.. bpo: 32323 .. date: 2017-12-14-10-10-10 .. nonce: ideco .. section: Library

:func:urllib.parse.urlsplit does not convert zone-id (scope) to lower case for scoped IPv6 addresses in hostnames now.

.. bpo: 32302 .. date: 2017-12-13-22-38-08 .. nonce: othtTr .. section: Library

Fix bdist_wininst of distutils for CRT v142: it binary compatible with CRT v140.

.. bpo: 29711 .. date: 2017-12-13-22-10-36 .. nonce: hJjghA .. section: Library

Fix stop_serving in asyncio proactor loop kill all listening servers

.. bpo: 32308 .. date: 2017-12-13-20-31-30 .. nonce: CUbsb2 .. section: Library

:func:re.sub now replaces empty matches adjacent to a previous non-empty match.

.. bpo: 29970 .. date: 2017-12-13-19-02-38 .. nonce: uxVOpk .. section: Library

Abort asyncio SSLProtocol connection if handshake not complete within 10 seconds.

.. bpo: 32314 .. date: 2017-12-13-16-47-38 .. nonce: W4_U2j .. section: Library

Implement asyncio.run().

.. bpo: 17852 .. date: 2017-12-13-00-00-37 .. nonce: Q8BP8N .. section: Library

Revert incorrect fix based on misunderstanding of _Py_PyAtExit() semantics.

.. bpo: 32296 .. date: 2017-12-12-18-01-01 .. nonce: bwscHz .. section: Library

Implement asyncio._get_running_loop() and get_event_loop() in C. This makes them 4x faster.

.. bpo: 32250 .. date: 2017-12-12-16-58-20 .. nonce: UljTa0 .. section: Library

Implement asyncio.current_task() and asyncio.all_tasks(). Add helpers intended to be used by alternative task implementations: asyncio._register_task, asyncio._enter_task, asyncio._leave_task and asyncio._unregister_task. Deprecate asyncio.Task.current_task() and asyncio.Task.all_tasks().

.. bpo: 32255 .. date: 2017-12-12-07-29-06 .. nonce: 2bfNmM .. section: Library

A single empty field is now always quoted when written into a CSV file. This allows to distinguish an empty row from a row consisting of a single empty field. Patch by Licht Takeuchi.

.. bpo: 32277 .. date: 2017-12-11-09-53-14 .. nonce: jkKiVC .. section: Library

Raise NotImplementedError instead of SystemError on platforms where chmod(..., follow_symlinks=False) is not supported. Patch by Anthony Sottile.

.. bpo: 30050 .. date: 2017-12-10-23-44-56 .. nonce: 4SZ3lY .. section: Library

New argument warn_on_full_buffer to signal.set_wakeup_fd lets you control whether Python prints a warning on stderr when the wakeup fd buffer overflows.

.. bpo: 29137 .. date: 2017-12-10-21-19-14 .. nonce: CFcON1 .. section: Library

The fpectl library has been removed. It was never enabled by default, never worked correctly on x86-64, and it changed the Python ABI in ways that caused unexpected breakage of C extensions.

.. bpo: 32273 .. date: 2017-12-10-19-14-55 .. nonce: 5KKlCv .. section: Library

Move asyncio.test_utils to test.test_asyncio.

.. bpo: 32272 .. date: 2017-12-10-18-59-13 .. nonce: Mu84Am .. section: Library

Remove asyncio.async() function.

.. bpo: 32269 .. date: 2017-12-10-12-30-13 .. nonce: Q85pKj .. section: Library

Add asyncio.get_running_loop() function.

.. bpo: 32265 .. date: 2017-12-10-00-57-51 .. nonce: kELtTE .. section: Library

All class and static methods of builtin types now are correctly classified by inspect.classify_class_attrs() and grouped in pydoc output. Added types.ClassMethodDescriptorType for unbound class methods of builtin types.

.. bpo: 32253 .. date: 2017-12-09-11-30-35 .. nonce: TQHSYF .. section: Library

Deprecate yield from lock, await lock, with (yield from lock) and with await lock for asyncio synchronization primitives.

.. bpo: 22589 .. date: 2017-12-08-15-09-41 .. nonce: 8ouqI6 .. section: Library

Changed MIME type of .bmp from 'image/x-ms-bmp' to 'image/bmp'

.. bpo: 32193 .. date: 2017-12-08-11-02-26 .. nonce: NJe_TQ .. section: Library

Convert asyncio to use async/await syntax. Old styled yield from is still supported too.

.. bpo: 32206 .. date: 2017-12-07-13-14-40 .. nonce: obm4OM .. section: Library

Add support to run modules with pdb

.. bpo: 32227 .. date: 2017-12-05-13-25-15 .. nonce: 3vnWFS .. section: Library

functools.singledispatch now supports registering implementations using type annotations.

.. bpo: 15873 .. date: 2017-12-04-17-41-40 .. nonce: -T4TRK .. section: Library

Added new alternate constructors :meth:datetime.datetime.fromisoformat, :meth:datetime.time.fromisoformat and :meth:datetime.date.fromisoformat as the inverse operation of each classes's respective isoformat methods.

.. bpo: 32199 .. date: 2017-12-04-12-23-26 .. nonce: nGof4v .. section: Library

The getnode() ip getter now uses 'ip link' instead of 'ip link list'.

.. bpo: 32143 .. date: 2017-11-26-17-28-26 .. nonce: o7YdXL .. section: Library

os.statvfs() includes the f_fsid field from statvfs(2)

.. bpo: 26439 .. date: 2017-11-24-08-35-43 .. nonce: IC45_f .. section: Library

Fix ctypes.util.find_library() for AIX by implementing ctypes._aix.find_library() Patch by: Michael Felt

.. bpo: 31993 .. date: 2017-11-10-00-05-08 .. nonce: -OMNg8 .. section: Library

The pickler now uses less memory when serializing large bytes and str objects into a file. Pickles created with protocol 4 will require less memory for unpickling large bytes and str objects.

.. bpo: 27456 .. date: 2017-11-02-11-57-41 .. nonce: snzyTC .. section: Library

Ensure TCP_NODELAY is set on Linux. Tests by Victor Stinner.

.. bpo: 31778 .. date: 2017-10-18-17-29-30 .. nonce: B6vAkP .. section: Library

ast.literal_eval() is now more strict. Addition and subtraction of arbitrary numbers no longer allowed.

.. bpo: 31802 .. date: 2017-10-17-14-52-14 .. nonce: sYj2Zv .. section: Library

Importing native path module (posixpath, ntpath) now works even if the os module still is not imported.

.. bpo: 30241 .. date: 2017-10-10-18-56-46 .. nonce: F_go20 .. section: Library

Add contextlib.AbstractAsyncContextManager. Patch by Jelle Zijlstra.

.. bpo: 31699 .. date: 2017-10-05-11-06-32 .. nonce: MF47Y6 .. section: Library

Fix deadlocks in :class:concurrent.futures.ProcessPoolExecutor when task arguments or results cause pickling or unpickling errors. This should make sure that calls to the :class:ProcessPoolExecutor API always eventually return.

.. bpo: 15216 .. date: 2017-09-16-02-56-33 .. nonce: lqXCTT .. section: Library

TextIOWrapper.reconfigure() supports changing encoding, errors, and newline.

.. bpo: 32418 .. date: 2017-12-24-17-29-37 .. nonce: eZe-ID .. section: Documentation

Add get_loop() method to Server and AbstractServer classes.

.. bpo: 32252 .. date: 2017-12-11-13-31-33 .. nonce: YnFw7J .. section: Tests

Fix faulthandler_suppress_crash_report() used to prevent core dump files when testing crashes. getrlimit() returns zero on success.

.. bpo: 32002 .. date: 2017-11-11-16-35-18 .. nonce: itDxIo .. section: Tests

Adjust C locale coercion testing for the empty locale and POSIX locale cases to more readily adjust to platform dependent behaviour.

.. bpo: 19764 .. date: 2017-08-18-18-00-24 .. nonce: ODpc9y .. section: Windows

Implement support for subprocess.Popen(close_fds=True) on Windows. Patch by Segev Finer.

.. bpo: 24960 .. date: 2017-12-22-09-25-51 .. nonce: TGdAgO .. section: Tools/Demos

2to3 and lib2to3 can now read pickled grammar files using pkgutil.get_data() rather than probing the filesystem. This lets 2to3 and lib2to3 work when run from a zipfile.

.. bpo: 32030 .. date: 2017-12-20-23-22-32 .. nonce: d1dcwh .. section: C API

Py_Initialize() doesn't reset the memory allocators to default if the PYTHONMALLOC environment variable is not set.

.. bpo: 29084 .. date: 2017-12-16-09-59-35 .. nonce: ZGJ-LJ .. section: C API

Undocumented C API for OrderedDict has been excluded from the limited C API. It was added by mistake and actually never worked in the limited C API.

.. bpo: 32264 .. date: 2017-12-12-23-09-46 .. nonce: ahRlOI .. section: C API

Moved the pygetopt.h header into internal/, since it has no public APIs.

.. bpo: 32241 .. date: 2017-12-07-15-58-15 .. nonce: LbyQt6 .. section: C API

:c:func:!Py_SetProgramName and :c:func:!Py_SetPythonHome now take the const wchar * arguments instead of wchar *.