3.11.0a5.rst

Remove two invalid "peephole" optimizations from the bytecode compiler.

Do not create frame objects when creating :class:`super` object. Patch by Kumar Aditya.

Added more fined-grained specialization failure stats regarding the COMPARE_OP bytecode.

The delegation of :func:`int` to :meth:`__trunc__` is now deprecated. Calling int(a) when type(a) implements :meth:`__trunc__` but not :meth:`__int__` or :meth:`__index__` now raises a :exc:`DeprecationWarning`.

Reorder code emitted by the compiler for a :keyword:`try`-:keyword:`except` block so that the :keyword:`else` block's code immediately follows the :keyword:`try` body (without a jump). This is more optimal for the happy path.

Allow passing iterable as a keyword argument to :func:`enumerate` again. Patch by Jelle Zijlstra.

Replace several stack manipulation instructions (DUP_TOP, DUP_TOP_TWO, ROT_TWO, ROT_THREE, ROT_FOUR, and ROT_N) with new :opcode:`COPY` and :opcode:`SWAP` instructions.

Use two or three bytecodes to implement most calls.

Calls without named arguments are implemented as a sequence of two instructions: PRECALL; CALL. Calls with named arguments are implemented as a sequence of three instructions: PRECALL; KW_NAMES; CALL. There are two different PRECALL instructions: PRECALL_FUNTION and PRECALL_METHOD. The latter pairs with LOAD_METHOD.

This partition into pre-call and call allows better specialization, and thus better performance ultimately.

There is no change in semantics.

Fix an assert when parsing some invalid N escape sequences in f-strings.

Improve error message on invalid calls to :meth:`BaseExceptionGroup.__new__`.

Fix memory leak in code objects generated by deepfreeze. Patch by Kumar Aditya.

Speed up calls to :meth:`weakref.ref.__call__` by using the PEP 590 vectorcall calling convention. Patch by Donghee Na.

Fix a race condition on setting a type __bases__ attribute: the internal function add_subclass() now gets the PyTypeObject.tp_subclasses member after calling :c:func:`PyWeakref_NewRef` which can trigger a garbage collection which can indirectly modify PyTypeObject.tp_subclasses. Patch by Victor Stinner.

python -X showrefcount now shows the total reference count after clearing and destroyed the main Python interpreter. Previously, it was shown before. Patch by Victor Stinner.

Add ASYNC_GEN_WRAP opcode to wrap the value to be yielded in async generators. Removes the need to special case async generators in the YIELD_VALUE instruction.

Optimize some modulo operations in Objects/longobject.c. Patch by Jeremiah Vivian.

Add new RETURN_GENERATOR bytecode to make generators. Simplifies calling Python functions in the VM, as they no longer any need to special case generator functions.

Also add JUMP_NO_INTERRUPT bytecode that acts like JUMP_ABSOLUTE, but does not check for interrupts.

The integer division // implementation has been optimized to better let the compiler understand its constraints. It can be 20% faster on the amd64 platform when dividing an int by a value smaller than 2**30.

Fix invalid signature of _zoneinfo's module_free function to resolve a crash on wasm32-emscripten platform.

Ensure that "small" integers created by :meth:`int.from_bytes` and :class:`decimal.Decimal` are properly cached.

Fix the class building error when the arguments are constants and CALL_FUNCTION_EX is used.

Fixes calculation of :data:`sys._base_executable` when inside a virtual environment that uses symlinks with different binary names than the base environment provides.

Correctly calculate indentation levels for lines with whitespace character that are ended by line continuation characters. Patch by Pablo Galindo

Add CAN Socket support for NetBSD.

Do not use POSIX semaphores on NetBSD

Improve the :exc:`TypeError` message for non-string second arguments passed to the built-in functions :func:`getattr` and :func:`hasattr`. Patch by Géry Ogam.

Restore support for non-integer arguments of :func:`random.randrange` and :func:`random.randint`.

Make the IDLE doc URL on the About IDLE dialog clickable.

Remove loop variables that are leaking into modules' namespaces.

In :func:`typing.get_type_hints`, support evaluating bare stringified ClassVar annotations. Patch by Gregory Beauregard.

Don't leak x & uspace intermediate vars in :class:`textwrap.TextWrapper`.

Add the get_write_buffer_limits method to :class:`asyncio.transports.WriteTransport` and to the SSL transport.

Note the configparser deprecations will be removed in Python 3.12.

The deprecated :mod:`unittest` APIs removed in 3.11a1 have been temporarily restored to be removed in 3.12 while cleanups in external projects go in.

In :func:`typing.get_type_hints`, support evaluating stringified ClassVar and Final annotations inside Annotated. Patch by Gregory Beauregard.

Add missing test for :class:`types.TracebackType` and :class:`types.FrameType`. Calculate them directly from the caught exception without calling :func:`sys.exc_info`.

Allow :data:`typing.Annotated` to wrap :data:`typing.Final` and :data:`typing.ClassVar`. Patch by Gregory Beauregard.

Remove :meth:`~object.__class_getitem__` from :class:`pathlib.PurePath` as this class was not supposed to be generic.

Fix command-line option -d/--directory in module :mod:`http.server` which is ignored when combined with command-line option --cgi. Patch by Géry Ogam.

Make :meth:`mock.patch` raise a :exc:`TypeError` with a relevant error message on invalid arg. Previously it allowed a cryptic :exc:`AttributeError` to escape.

In importlib.metadata.EntryPoint.pattern, avoid potential REDoS by limiting ambiguity in consecutive whitespace.

Removed private method from importlib.metadata.Path. Sync with importlib_metadata 4.10.0.

Remove unused branch from typing._remove_dups_flatten

:mod:`asyncio` generic classes now return :class:`types.GenericAlias` in __class_getitem__ instead of the same class.

Support passing filter instances in the filters values of handlers and loggers in the dictionary passed to :func:`logging.config.dictConfig`.

Use dis.Positions in dis.Instruction instead of a regular tuple.

:mod:`pdb` now gracefully handles help when :attr:`~module.__doc__` is missing, for example when run with pregenerated optimized .pyc files.

Python uses the same time Epoch on all platforms. Add an explicit unit test to ensure that it's the case. Patch by Victor Stinner.

Add :func:`typing.reveal_type`. Patch by Jelle Zijlstra.

:mod:`subprocess` now imports Windows-specific imports when msvcrt module is available, and POSIX-specific imports on all other platforms. This gives a clean exception when _posixsubprocess is not available (e.g. Emscripten browser target).

IntEnum, IntFlag, and StrEnum use the mixed-in type for their str() and format() output.

Optimize :meth:`pathlib.Path.iterdir` by removing an unnecessary check for special entries.

Document :meth:`pathlib.Path.absolute` (which has always existed).

The pathlib module's obsolete and internal _Accessor class has been removed to prepare the terrain for upcoming enhancements to the module.

Speed up :func:`math.isqrt` for small positive integers by replacing two division steps with a lookup table.

Improve error message when creating a new :class:`enum.Enum` type subclassing an existing Enum with _member_names_ using :meth:`enum.Enum.__call__`.

Fix a bug in :func:`inspect.signature` that was causing it to fail on some subclasses of classes with a __text_signature__ referencing module globals. Patch by Weipeng Hong.

Fixed case where failing :func:`asyncio.ensure_future` did not close the coroutine. Patch by Kumar Aditya.

Fix an issue with :meth:`tarfile.TarFile.getmember` getting a directory name with a trailing slash.

Update :mod:`zoneinfo` to rely on importlib.resources traversable API.

Now :func:`inspect.getmembers` only gets :attr:`__bases__` attribute from class type. Patch by Weipeng Hong.

Fix exception in argparse help text generation if a :class:`argparse.BooleanOptionalAction` argument's default is argparse.SUPPRESS and it has help specified. Patch by Felix Fontein.

Fix substitution of :class:`~typing.ParamSpec` in :data:`~typing.Concatenate` with different parameter expressions. Substitution with a list of types returns now a tuple of types. Substitution with Concatenate returns now a Concatenate with concatenated lists of arguments.

Fixes :file:`escape4chm.py` script used when building the CHM documentation file

Mocks can no longer be provided as the specs for other Mocks. As a result, an already-mocked object cannot be passed to mock.Mock(). This can uncover bugs in tests since these Mock-derived Mocks will always pass certain tests (e.g. isinstance) and builtin assert functions (e.g. assert_called_once_with) will unconditionally pass.

Ensures test_importlib.test_windows cleans up registry keys after completion.

test_ftplib now silently ignores socket errors to prevent logging unhandled threading exceptions. Patch by Victor Stinner.

Fix test_gdb.test_pycfunction() for Python built with clang -Og. Tolerate inlined functions in the gdb traceback. Patch by Victor Stinner.

Fix a Python crash in test_lib2to3 when using Python built in debug mode: limit the recursion limit. Patch by Victor Stinner.

test_peg_generator now disables compiler optimization when testing compilation of its own C extensions to significantly speed up the testing on non-debug builds of CPython.

Fix test_json tests checking for :exc:`RecursionError`: modify these tests to use support.infinite_recursion(). Patch by Victor Stinner.

Skip test_builtin PTY tests on non-ASCII characters if the readline module is loaded. The readline module changes input() behavior, but test_builtin is not intended to test the readline module. Patch by Victor Stinner.

Add :func:`test.support.requires_fork` decorators to mark tests that require a working :func:`os.fork`.

Add :func:`test.support.requires_subprocess` decorator to mark tests which require working :mod:`subprocess` module or os.spawn*. The wasm32-emscripten platform has no support for processes.

Disable 'descriptions' when running tests internally.

Tidied up configure.ac so that conftest.c is truncated rather than appended. This assists in the case where the 'rm' of conftest.c fails to happen between tests. Downstream issues such as a clobbered SOABI can result.

Fix the test checking if the C compiler supports -Og option in the ./configure script to also use -Og on clang which supports it. Patch by Victor Stinner.

Fix GCC detection in setup.py when cross-compiling. The C compiler is now run with LC_ALL=C. Previously, the detection failed with a German locale.

:program:`configure` no longer uses AC_C_CHAR_UNSIGNED macro and pyconfig.h no longer defines reserved symbol __CHAR_UNSIGNED__.

Use global singletons for single byte bytes objects in deepfreeze.

Deepfreeze now uses cached small integers as it saves some space for common small integers.

Merge all deep-frozen files into one for space savings. Patch by Kumar Aditya.

The build now defaults to using 30-bit digits for Python integers. Previously either 15-bit or 30-bit digits would be selected, depending on the platform. 15-bit digits may still be selected using the --enable-big-digits=15 option to the configure script, or by defining PYLONG_BITS_IN_DIGIT in pyconfig.h.

Update Windows installer to use SQLite 3.37.2.

Detect musl libc as a separate SOABI (tagged as linux-musl).

The traditional EXE/MSI based installer for Windows is now available for ARM64

os.path.abspath("C:CON") is now fixed to return "\.CON", not the same path. The regression was true of all legacy DOS devices such as COM1, LPT1, or NUL.

The installer now offers a command-line only option to add the installation directory to the end of :envvar:`PATH` instead of at the start.

Update macOS installer to SQLite 3.37.2.

Clarify close, quit, and exit in IDLE. In the File menu, 'Close' and 'Exit' are now 'Close Window' (the current one) and 'Exit' is now 'Exit IDLE' (by closing all windows). In Shell, 'quit()' and 'exit()' mean 'close Shell'. If there are no other windows, this also exits IDLE.

Remove the PyHeapType_GET_MEMBERS() macro. It was exposed in the public C API by mistake, it must only be used by Python internally. Use the PyTypeObject.tp_members member instead. Patch by Victor Stinner.

Move _Py_GetAllocatedBlocks() and _PyObject_DebugMallocStats() private functions to the internal C API. Patch by Victor Stinner.

The internal function _PyType_GetModuleByDef now correctly handles inheritance patterns involving static types.

:c:type:`Py_buffer` and various Py_buffer related functions are now part of the limited API and stable ABI.

Fixed bug in the tokenizer that prevented PyRun_InteractiveOne from parsing from the provided FD.