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.
__class_getitem__ is now an automatic class method.
Add AIX uuid library support for RFC4122 using uuid_create() in libc.a
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.
Make MRO computation faster when a class inherits from a single base.
The error message of a TypeError raised when unpack non-iterable is now more specific.
The __debug__ constant is now optimized out at compile time. This fixes
also bpo-22091.
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.
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.
Fix an unnecessary ifdef in the include of VersionHelpers.h in socketmodule on Windows.
Implement TracebackType.__new__ to allow Python-level creation of traceback objects, and make TracebackType.tb_next mutable.
Don't byte swap the input keys to the SipHash algorithm on big-endian platforms. This should ensure siphash gives consistent results across platforms.
Improve the error message logic for object.__new__ and object.__init__. Patch by Sanyam Khurana.
-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.
-X dev now injects a 'default' entry into sys.warnoptions, ensuring
that it behaves identically to actually passing -Wdefault at the command
line.
Add a new UTF-8 mode: implementation of the PEP 540.
PEP 560: Add support for __mro_entries__ and __class_getitem__. Implemented
by Ivan Levkivskyi.
PEP 562: Add support for module __getattr__ and __dir__. Implemented
by Ivan Levkivskyi.
The atexit module now has its callback stored per interpreter.
Implement PEP 552 (Deterministic pycs). Python now supports invalidating bytecode cache files bashed on a source content hash rather than source last-modified time.
Move constant folding from bytecode layer to AST layer. Original patch by Eugene Toder.
Now that dict is defined as keeping insertion order, drop OrderedDict and just use plain dict.
Add params to dataclasses.make_dataclasses(): init, repr, eq, order, hash, and frozen. Pass them through to dataclass().
Make type information optional on dataclasses.make_dataclass(). If omitted, the string 'typing.Any' is used.
Add dataclasses.is_dataclass(obj), which returns True if obj is a dataclass or an instance of one.
Improve frame repr() to mention filename, code name and current line number.
asyncio: Implement loop.start_tls()
Return the new file descriptor (i.e., the second argument) from os.dup2.
Previously, None was always returned.
functools.lru_cache uses less memory (3 words for each cached key) and
takes about 1/3 time for cyclic GC.
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.
asyncio: Add Task.get_loop() and Future.get_loop()
Don't unsubscribe signals in asyncio UNIX event loop on interpreter shutdown.
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.
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.
asyncio.transport.resume_reading() and pause_reading() are now idempotent. New transport.is_reading() method is added.
Optimize asyncio.gather(); now up to 15% faster.
Use fastpath in asyncio.sleep if delay<0 (2x boost)
Optimize asyncio.Future schedule/add/remove callback. The optimization shows 3-6% performance improvements of async/await code.
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.
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.
Implement asyncio.create_task(coro) shortcut
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.
:func:`urllib.parse.urlsplit()` does not convert zone-id (scope) to lower case for scoped IPv6 addresses in hostnames now.
Fix bdist_wininst of distutils for CRT v142: it binary compatible with CRT v140.
Fix stop_serving in asyncio proactor loop kill all listening servers
:func:`re.sub()` now replaces empty matches adjacent to a previous non-empty match.
Abort asyncio SSLProtocol connection if handshake not complete within 10 seconds.
Implement asyncio.run().
Revert incorrect fix based on misunderstanding of _Py_PyAtExit() semantics.
Implement asyncio._get_running_loop() and get_event_loop() in C. This makes them 4x faster.
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().
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.
Raise NotImplementedError instead of SystemError on platforms where
chmod(..., follow_symlinks=False) is not supported. Patch by Anthony
Sottile.
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.
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.
Move asyncio.test_utils to test.test_asyncio.
Remove asyncio.async() function.
Add asyncio.get_running_loop() function.
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.
Deprecate yield from lock, await lock, with (yield from lock)
and with await lock for asyncio synchronization primitives.
Changed MIME type of .bmp from 'image/x-ms-bmp' to 'image/bmp'
Convert asyncio to use async/await syntax. Old styled yield from is
still supported too.
Add support to run modules with pdb
functools.singledispatch now supports registering implementations using
type annotations.
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.
The getnode() ip getter now uses 'ip link' instead of 'ip link list'.
os.statvfs() includes the f_fsid field from statvfs(2)
Fix ctypes.util.find_library() for AIX by implementing ctypes._aix.find_library() Patch by: Michael Felt
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.
Ensure TCP_NODELAY is set on Linux. Tests by Victor Stinner.
ast.literal_eval() is now more strict. Addition and subtraction of arbitrary numbers no longer allowed.
Importing native path module (posixpath, ntpath) now works even if
the os module still is not imported.
Add contextlib.AbstractAsyncContextManager. Patch by Jelle Zijlstra.
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.
TextIOWrapper.reconfigure() supports changing encoding, errors, and
newline.
Add get_loop() method to Server and AbstractServer classes.
Fix faulthandler_suppress_crash_report() used to prevent core dump files when testing crashes. getrlimit() returns zero on success.
Adjust C locale coercion testing for the empty locale and POSIX locale cases to more readily adjust to platform dependent behaviour.
Implement support for subprocess.Popen(close_fds=True) on Windows. Patch
by Segev Finer.
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.
Py_Initialize() doesn't reset the memory allocators to default if the
PYTHONMALLOC environment variable is not set.
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.
Moved the pygetopt.h header into internal/, since it has no public APIs.
:c:func:`!Py_SetProgramName` and :c:func:`!Py_SetPythonHome` now take the
const wchar * arguments instead of wchar *.