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****************************
What's New In Python 3.13
****************************
:Editor: TBD
.. Rules for maintenance:
* Anyone can add text to this document. Do not spend very much time
on the wording of your changes, because your text will probably
get rewritten to some degree.
* The maintainer will go through Misc/NEWS periodically and add
changes; it's therefore more important to add your changes to
Misc/NEWS than to this file.
* This is not a complete list of every single change; completeness
is the purpose of Misc/NEWS. Some changes I consider too small
or esoteric to include. If such a change is added to the text,
I'll just remove it. (This is another reason you shouldn't spend
too much time on writing your addition.)
* If you want to draw your new text to the attention of the
maintainer, add 'XXX' to the beginning of the paragraph or
section.
* It's OK to just add a fragmentary note about a change. For
example: "XXX Describe the transmogrify() function added to the
socket module." The maintainer will research the change and
write the necessary text.
* You can comment out your additions if you like, but it's not
necessary (especially when a final release is some months away).
* Credit the author of a patch or bugfix. Just the name is
sufficient; the e-mail address isn't necessary.
* It's helpful to add the issue number as a comment:
XXX Describe the transmogrify() function added to the socket
module.
(Contributed by P.Y. Developer in :gh:`12345`.)
This saves the maintainer the effort of going through the VCS log
when researching a change.
This article explains the new features in Python 3.13, compared to 3.12.
For full details, see the :ref:`changelog <changelog>`.
.. note::
Prerelease users should be aware that this document is currently in draft
form. It will be updated substantially as Python 3.13 moves towards release,
so it's worth checking back even after reading earlier versions.
Summary -- Release highlights
=============================
.. This section singles out the most important changes in Python 3.13.
Brevity is key.
.. PEP-sized items next.
Important deprecations, removals or restrictions:
* :ref:`PEP 594 <whatsnew313-pep594>`: The remaining 19 "dead batteries"
have been removed from the standard library:
:mod:`!aifc`, :mod:`!audioop`, :mod:`!cgi`, :mod:`!cgitb`, :mod:`!chunk`,
:mod:`!crypt`, :mod:`!imghdr`, :mod:`!mailcap`, :mod:`!msilib`, :mod:`!nis`,
:mod:`!nntplib`, :mod:`!ossaudiodev`, :mod:`!pipes`, :mod:`!sndhdr`, :mod:`!spwd`,
:mod:`!sunau`, :mod:`!telnetlib`, :mod:`!uu` and :mod:`!xdrlib`.
* :pep:`602` ("Annual Release Cycle for Python") has been updated:
* Python 3.9 - 3.12 have one and a half years of full support,
followed by three and a half years of security fixes.
* Python 3.13 and later have two years of full support,
followed by three years of security fixes.
New Features
============
Improved Error Messages
-----------------------
* The interpreter now colorizes error messages when displaying tracebacks by default.
This feature can be controlled via the new :envvar:`PYTHON_COLORS` environment
variable as well as the canonical ``NO_COLOR`` and ``FORCE_COLOR`` environment
variables. (Contributed by Pablo Galindo Salgado in :gh:`112730`.)
Other Language Changes
======================
* Allow the *count* argument of :meth:`str.replace` to be a keyword.
(Contributed by Hugo van Kemenade in :gh:`106487`.)
* Compiler now strip indents from docstrings.
This will reduce the size of :term:`bytecode cache <bytecode>` (e.g. ``.pyc`` file).
For example, cache file size for ``sqlalchemy.orm.session`` in SQLAlchemy 2.0
is reduced by about 5%.
This change will affect tools using docstrings, like :mod:`doctest`.
(Contributed by Inada Naoki in :gh:`81283`.)
* The :func:`compile` built-in can now accept a new flag,
``ast.PyCF_OPTIMIZED_AST``, which is similar to ``ast.PyCF_ONLY_AST``
except that the returned ``AST`` is optimized according to the value
of the ``optimize`` argument.
(Contributed by Irit Katriel in :gh:`108113`).
* :mod:`multiprocessing`, :mod:`concurrent.futures`, :mod:`compileall`:
Replace :func:`os.cpu_count` with :func:`os.process_cpu_count` to select the
default number of worker threads and processes. Get the CPU affinity
if supported.
(Contributed by Victor Stinner in :gh:`109649`.)
* :func:`os.path.realpath` now resolves MS-DOS style file names even if
the file is not accessible.
(Contributed by Moonsik Park in :gh:`82367`.)
* Fixed a bug where a :keyword:`global` declaration in an :keyword:`except` block
is rejected when the global is used in the :keyword:`else` block.
(Contributed by Irit Katriel in :gh:`111123`.)
* Added a new environment variable :envvar:`PYTHON_FROZEN_MODULES`. It
determines whether or not frozen modules are ignored by the import machinery,
equivalent of the :option:`-X frozen_modules <-X>` command-line option.
(Contributed by Yilei Yang in :gh:`111374`.)
New Modules
===========
* None yet.
Improved Modules
================
ast
---
* :func:`ast.parse` now accepts an optional argument ``optimize``
which is passed on to the :func:`compile` built-in. This makes it
possible to obtain an optimized ``AST``.
(Contributed by Irit Katriel in :gh:`108113`).
array
-----
* Add ``'w'`` type code (``Py_UCS4``) that can be used for Unicode strings.
It can be used instead of ``'u'`` type code, which is deprecated.
(Contributed by Inada Naoki in :gh:`80480`.)
asyncio
-------
* :meth:`asyncio.loop.create_unix_server` will now automatically remove
the Unix socket when the server is closed.
(Contributed by Pierre Ossman in :gh:`111246`.)
copy
----
* Add :func:`copy.replace` function which allows to create a modified copy of
an object, which is especially useful for immutable objects.
It supports named tuples created with the factory function
:func:`collections.namedtuple`, :class:`~dataclasses.dataclass` instances,
various :mod:`datetime` objects, :class:`~inspect.Signature` objects,
:class:`~inspect.Parameter` objects, :ref:`code object <code-objects>`, and
any user classes which define the :meth:`!__replace__` method.
(Contributed by Serhiy Storchaka in :gh:`108751`.)
dis
---
* Change the output of :mod:`dis` module functions to show logical
labels for jump targets and exception handlers, rather than offsets.
The offsets can be added with the new ``-O`` command line option or
the ``show_offsets`` parameter.
(Contributed by Irit Katriel in :gh:`112137`.)
dbm
---
* Add :meth:`dbm.gnu.gdbm.clear` and :meth:`dbm.ndbm.ndbm.clear` methods that remove all items
from the database.
(Contributed by Donghee Na in :gh:`107122`.)
doctest
-------
* The :meth:`doctest.DocTestRunner.run` method now counts the number of skipped
tests. Add :attr:`doctest.DocTestRunner.skips` and
:attr:`doctest.TestResults.skipped` attributes.
(Contributed by Victor Stinner in :gh:`108794`.)
glob
----
* Add :func:`glob.translate` function that converts a path specification with
shell-style wildcards to a regular expression.
(Contributed by Barney Gale in :gh:`72904`.)
io
--
The :class:`io.IOBase` finalizer now logs the ``close()`` method errors with
:data:`sys.unraisablehook`. Previously, errors were ignored silently by default,
and only logged in :ref:`Python Development Mode <devmode>` or on :ref:`Python
built on debug mode <debug-build>`.
(Contributed by Victor Stinner in :gh:`62948`.)
ipaddress
---------
* Add the :attr:`ipaddress.IPv4Address.ipv6_mapped` property, which returns the IPv4-mapped IPv6 address.
(Contributed by Charles Machalow in :gh:`109466`.)
mmap
----
* The :class:`mmap.mmap` class now has an :meth:`~mmap.mmap.seekable` method
that can be used where it requires a file-like object with seekable and
the :meth:`~mmap.mmap.seek` method return the new absolute position.
(Contributed by Donghee Na and Sylvie Liberman in :gh:`111835`.)
opcode
------
* Move ``opcode.ENABLE_SPECIALIZATION`` to ``_opcode.ENABLE_SPECIALIZATION``.
This field was added in 3.12, it was never documented and is not intended for
external usage. (Contributed by Irit Katriel in :gh:`105481`.)
* Removed ``opcode.is_pseudo``, ``opcode.MIN_PSEUDO_OPCODE`` and
``opcode.MAX_PSEUDO_OPCODE``, which were added in 3.12, were never
documented or exposed through ``dis``, and were not intended to be
used externally.
os
--
* Add :func:`os.process_cpu_count` function to get the number of logical CPUs
usable by the calling thread of the current process.
(Contributed by Victor Stinner in :gh:`109649`.)
* Add a low level interface for Linux's timer notification file descriptors
via :func:`os.timerfd_create`,
:func:`os.timerfd_settime`, :func:`os.timerfd_settime_ns`,
:func:`os.timerfd_gettime`, and :func:`os.timerfd_gettime_ns`,
:const:`os.TFD_NONBLOCK`, :const:`os.TFD_CLOEXEC`,
:const:`os.TFD_TIMER_ABSTIME`, and :const:`os.TFD_TIMER_CANCEL_ON_SET`
(Contributed by Masaru Tsuchiyama in :gh:`108277`.)
* :func:`os.cpu_count` and :func:`os.process_cpu_count` can be overridden through
the new environment variable :envvar:`PYTHON_CPU_COUNT` or the new command-line option
:option:`-X cpu_count <-X>`. This option is useful for users who need to limit
CPU resources of a container system without having to modify the container (application code).
(Contributed by Donghee Na in :gh:`109595`)
pathlib
-------
* Add :exc:`pathlib.UnsupportedOperation`, which is raised instead of
:exc:`NotImplementedError` when a path operation isn't supported.
(Contributed by Barney Gale in :gh:`89812`.)
* Add :meth:`pathlib.Path.from_uri`, a new constructor to create a :class:`pathlib.Path`
object from a 'file' URI (``file:/``).
(Contributed by Barney Gale in :gh:`107465`.)
* Add support for recursive wildcards in :meth:`pathlib.PurePath.match`.
(Contributed by Barney Gale in :gh:`73435`.)
* Add *follow_symlinks* keyword-only argument to :meth:`pathlib.Path.glob`,
:meth:`~pathlib.Path.rglob`, :meth:`~pathlib.Path.is_file`,
:meth:`~pathlib.Path.is_dir`, :meth:`~pathlib.Path.owner`,
:meth:`~pathlib.Path.group`.
(Contributed by Barney Gale in :gh:`77609` and :gh:`105793`, and
Kamil Turek in :gh:`107962`).
pdb
---
* Add ability to move between chained exceptions during post mortem debugging in :func:`~pdb.pm` using
the new ``exceptions [exc_number]`` command for Pdb. (Contributed by Matthias
Bussonnier in :gh:`106676`.)
* Expressions/Statements whose prefix is a pdb command are now correctly
identified and executed.
(Contributed by Tian Gao in :gh:`108464`.)
* ``sys.path[0]`` will no longer be replaced by the directory of the script
being debugged when ``sys.flags.safe_path`` is set (via the :option:`-P`
command line option or :envvar:`PYTHONSAFEPATH` environment variable).
(Contributed by Tian Gao and Christian Walther in :gh:`111762`.)
re
--
* Rename :exc:`!re.error` to :exc:`re.PatternError` for improved clarity.
:exc:`!re.error` is kept for backward compatibility.
sqlite3
-------
* A :exc:`ResourceWarning` is now emitted if a :class:`sqlite3.Connection`
object is not :meth:`closed <sqlite3.Connection.close>` explicitly.
(Contributed by Erlend E. Aasland in :gh:`105539`.)
sys
---
* Add the :func:`sys._is_interned` function to test if the string was interned.
This function is not guaranteed to exist in all implementations of Python.
(Contributed by Serhiy Storchaka in :gh:`78573`.)
tkinter
-------
* Add :mod:`tkinter` widget methods:
:meth:`!tk_busy_hold`, :meth:`!tk_busy_configure`,
:meth:`!tk_busy_cget`, :meth:`!tk_busy_forget`,
:meth:`!tk_busy_current`, and :meth:`!tk_busy_status`.
(Contributed by Miguel, klappnase and Serhiy Storchaka in :gh:`72684`.)
* Add support of the "vsapi" element type in
the :meth:`~tkinter.ttk.Style.element_create` method of
:class:`tkinter.ttk.Style`.
(Contributed by Serhiy Storchaka in :gh:`68166`.)
traceback
---------
* Add *show_group* parameter to :func:`traceback.TracebackException.format_exception_only`
to format the nested exceptions of a :exc:`BaseExceptionGroup` instance, recursively.
(Contributed by Irit Katriel in :gh:`105292`.)
* Add the field *exc_type_str* to :class:`~traceback.TracebackException`, which
holds a string display of the *exc_type*. Deprecate the field *exc_type*
which holds the type object itself. Add parameter *save_exc_type* (default
``True``) to indicate whether ``exc_type`` should be saved.
(Contributed by Irit Katriel in :gh:`112332`.)
typing
------
* Add :func:`typing.get_protocol_members` to return the set of members
defining a :class:`typing.Protocol`. Add :func:`typing.is_protocol` to
check whether a class is a :class:`typing.Protocol`. (Contributed by Jelle Zijlstra in
:gh:`104873`.)
unicodedata
-----------
* The Unicode database has been updated to version 15.1.0. (Contributed by
James Gerity in :gh:`109559`.)
venv
----
* Add support for adding source control management (SCM) ignore files to a
virtual environment's directory. By default, Git is supported. This is
implemented as opt-in via the API which can be extended to support other SCMs
(:class:`venv.EnvBuilder` and :func:`venv.create`), and opt-out via the CLI
(using ``--without-scm-ignore-files``). (Contributed by Brett Cannon in
:gh:`108125`.)
warnings
--------
* The new :func:`warnings.deprecated` decorator provides a way to communicate
deprecations to :term:`static type checkers <static type checker>` and
to warn on usage of deprecated classes and functions. A runtime deprecation
warning may also be emitted when a decorated function or class is used at runtime.
See :pep:`702`. (Contributed by Jelle Zijlstra in :gh:`104003`.)
Optimizations
=============
* :func:`textwrap.indent` is now ~30% faster than before for large input.
(Contributed by Inada Naoki in :gh:`107369`.)
Deprecated
==========
* :mod:`array`: :mod:`array`'s ``'u'`` format code, deprecated in docs since Python 3.3,
emits :exc:`DeprecationWarning` since 3.13
and will be removed in Python 3.16.
Use the ``'w'`` format code instead.
(contributed by Hugo van Kemenade in :gh:`80480`)
* :mod:`ctypes`: Deprecate undocumented :func:`!ctypes.SetPointerType`
and :func:`!ctypes.ARRAY` functions.
Replace ``ctypes.ARRAY(item_type, size)`` with ``item_type * size``.
(Contributed by Victor Stinner in :gh:`105733`.)
* :mod:`getopt` and :mod:`optparse` modules: They are now
:term:`soft deprecated`: the :mod:`argparse` should be used for new projects.
Previously, the :mod:`optparse` module was already deprecated, its removal
was not scheduled, and no warnings was emitted: so there is no change in
practice.
(Contributed by Victor Stinner in :gh:`106535`.)
* :mod:`http.server`: :class:`http.server.CGIHTTPRequestHandler` now emits a
:exc:`DeprecationWarning` as it will be removed in 3.15. Process based CGI
http servers have been out of favor for a very long time. This code was
outdated, unmaintained, and rarely used. It has a high potential for both
security and functionality bugs. This includes removal of the ``--cgi``
flag to the ``python -m http.server`` command line in 3.15.
* :mod:`traceback`:
* The field *exc_type* of :class:`traceback.TracebackException` is
deprecated. Use *exc_type_str* instead.
* :mod:`typing`:
* Creating a :class:`typing.NamedTuple` class using keyword arguments to denote
the fields (``NT = NamedTuple("NT", x=int, y=int)``) is deprecated, and will
be disallowed in Python 3.15. Use the class-based syntax or the functional
syntax instead. (Contributed by Alex Waygood in :gh:`105566`.)
* When using the functional syntax to create a :class:`typing.NamedTuple`
class or a :class:`typing.TypedDict` class, failing to pass a value to the
'fields' parameter (``NT = NamedTuple("NT")`` or ``TD = TypedDict("TD")``) is
deprecated. Passing ``None`` to the 'fields' parameter
(``NT = NamedTuple("NT", None)`` or ``TD = TypedDict("TD", None)``) is also
deprecated. Both will be disallowed in Python 3.15. To create a NamedTuple
class with 0 fields, use ``class NT(NamedTuple): pass`` or
``NT = NamedTuple("NT", [])``. To create a TypedDict class with 0 fields, use
``class TD(TypedDict): pass`` or ``TD = TypedDict("TD", {})``.
(Contributed by Alex Waygood in :gh:`105566` and :gh:`105570`.)
* :func:`typing.no_type_check_decorator` is deprecated, and scheduled for
removal in Python 3.15. After eight years in the :mod:`typing` module, it
has yet to be supported by any major type checkers.
(Contributed by Alex Waygood in :gh:`106309`.)
* :data:`typing.AnyStr` is deprecated. In Python 3.16, it will be removed from
``typing.__all__``, and a :exc:`DeprecationWarning` will be emitted when it
is imported or accessed. It will be removed entirely in Python 3.18. Use
the new :ref:`type parameter syntax <type-params>` instead.
(Contributed by Michael The in :gh:`107116`.)
* :mod:`wave`: Deprecate the ``getmark()``, ``setmark()`` and ``getmarkers()``
methods of the :class:`wave.Wave_read` and :class:`wave.Wave_write` classes.
They will be removed in Python 3.15.
(Contributed by Victor Stinner in :gh:`105096`.)
* Passing more than one positional argument to :func:`sqlite3.connect` and the
:class:`sqlite3.Connection` constructor is deprecated. The remaining
parameters will become keyword-only in Python 3.15.
Deprecate passing name, number of arguments, and the callable as keyword
arguments, for the following :class:`sqlite3.Connection` APIs:
* :meth:`~sqlite3.Connection.create_function`
* :meth:`~sqlite3.Connection.create_aggregate`
Deprecate passing the callback callable by keyword for the following
:class:`sqlite3.Connection` APIs:
* :meth:`~sqlite3.Connection.set_authorizer`
* :meth:`~sqlite3.Connection.set_progress_handler`
* :meth:`~sqlite3.Connection.set_trace_callback`
The affected parameters will become positional-only in Python 3.15.
(Contributed by Erlend E. Aasland in :gh:`107948` and :gh:`108278`.)
* The ``dis.HAVE_ARGUMENT`` separator is deprecated. Check membership
in :data:`~dis.hasarg` instead.
(Contributed by Irit Katriel in :gh:`109319`.)
* Deprecate non-standard format specifier "N" for :class:`decimal.Decimal`.
It was not documented and only supported in the C implementation.
(Contributed by Serhiy Storchaka in :gh:`89902`.)
* Emit deprecation warning for non-integer numbers in :mod:`gettext` functions
and methods that consider plural forms even if the translation was not found.
(Contributed by Serhiy Storchaka in :gh:`88434`.)
* Calling :meth:`frame.clear` on a suspended frame raises :exc:`RuntimeError`
(as has always been the case for an executing frame).
(Contributed by Irit Katriel in :gh:`79932`.)
* Assignment to a function's :attr:`~function.__code__` attribute where the new code
object's type does not match the function's type, is deprecated. The
different types are: plain function, generator, async generator and
coroutine.
(Contributed by Irit Katriel in :gh:`81137`.)
Pending Removal in Python 3.14
------------------------------
* :mod:`argparse`: The *type*, *choices*, and *metavar* parameters
of :class:`!argparse.BooleanOptionalAction` are deprecated
and will be removed in 3.14.
(Contributed by Nikita Sobolev in :gh:`92248`.)
* :mod:`ast`: The following features have been deprecated in documentation
since Python 3.8, now cause a :exc:`DeprecationWarning` to be emitted at
runtime when they are accessed or used, and will be removed in Python 3.14:
* :class:`!ast.Num`
* :class:`!ast.Str`
* :class:`!ast.Bytes`
* :class:`!ast.NameConstant`
* :class:`!ast.Ellipsis`
Use :class:`ast.Constant` instead.
(Contributed by Serhiy Storchaka in :gh:`90953`.)
* :mod:`collections.abc`: Deprecated :class:`~collections.abc.ByteString`.
Prefer :class:`!Sequence` or :class:`~collections.abc.Buffer`.
For use in typing, prefer a union, like ``bytes | bytearray``,
or :class:`collections.abc.Buffer`.
(Contributed by Shantanu Jain in :gh:`91896`.)
* :mod:`email`: Deprecated the *isdst* parameter in :func:`email.utils.localtime`.
(Contributed by Alan Williams in :gh:`72346`.)
* :mod:`importlib`: ``__package__`` and ``__cached__`` will cease to be set or
taken into consideration by the import system (:gh:`97879`).
* :mod:`importlib.abc` deprecated classes:
* :class:`!importlib.abc.ResourceReader`
* :class:`!importlib.abc.Traversable`
* :class:`!importlib.abc.TraversableResources`
Use :mod:`importlib.resources.abc` classes instead:
* :class:`importlib.resources.abc.Traversable`
* :class:`importlib.resources.abc.TraversableResources`
(Contributed by Jason R. Coombs and Hugo van Kemenade in :gh:`93963`.)
* :mod:`itertools` had undocumented, inefficient, historically buggy,
and inconsistent support for copy, deepcopy, and pickle operations.
This will be removed in 3.14 for a significant reduction in code
volume and maintenance burden.
(Contributed by Raymond Hettinger in :gh:`101588`.)
* :mod:`multiprocessing`: The default start method will change to a safer one on
Linux, BSDs, and other non-macOS POSIX platforms where ``'fork'`` is currently
the default (:gh:`84559`). Adding a runtime warning about this was deemed too
disruptive as the majority of code is not expected to care. Use the
:func:`~multiprocessing.get_context` or
:func:`~multiprocessing.set_start_method` APIs to explicitly specify when
your code *requires* ``'fork'``. See :ref:`multiprocessing-start-methods`.
* :mod:`pathlib`: :meth:`~pathlib.PurePath.is_relative_to`,
:meth:`~pathlib.PurePath.relative_to`: passing additional arguments is
deprecated.
* :func:`pkgutil.find_loader` and :func:`pkgutil.get_loader`
now raise :exc:`DeprecationWarning`;
use :func:`importlib.util.find_spec` instead.
(Contributed by Nikita Sobolev in :gh:`97850`.)
* :mod:`pty`:
* ``master_open()``: use :func:`pty.openpty`.
* ``slave_open()``: use :func:`pty.openpty`.
* :func:`shutil.rmtree` *onerror* parameter is deprecated in 3.12,
and will be removed in 3.14: use the *onexc* parameter instead.
* :mod:`sqlite3`:
* :data:`~sqlite3.version` and :data:`~sqlite3.version_info`.
* :meth:`~sqlite3.Cursor.execute` and :meth:`~sqlite3.Cursor.executemany`
if :ref:`named placeholders <sqlite3-placeholders>` are used and
*parameters* is a sequence instead of a :class:`dict`.
* date and datetime adapter, date and timestamp converter:
see the :mod:`sqlite3` documentation for suggested replacement recipes.
* :class:`types.CodeType`: Accessing :attr:`~codeobject.co_lnotab` was
deprecated in :pep:`626`
since 3.10 and was planned to be removed in 3.12,
but it only got a proper :exc:`DeprecationWarning` in 3.12.
May be removed in 3.14.
(Contributed by Nikita Sobolev in :gh:`101866`.)
* :mod:`typing`: :class:`~typing.ByteString`, deprecated since Python 3.9,
now causes a :exc:`DeprecationWarning` to be emitted when it is used.
* :class:`!urllib.parse.Quoter` is deprecated: it was not intended to be a
public API.
(Contributed by Gregory P. Smith in :gh:`88168`.)
* :mod:`xml.etree.ElementTree`: Testing the truth value of an
:class:`~xml.etree.ElementTree.Element` is deprecated and will raise an
exception in Python 3.14.
Pending Removal in Python 3.15
------------------------------
* :class:`http.server.CGIHTTPRequestHandler` will be removed along with its
related ``--cgi`` flag to ``python -m http.server``. It was obsolete and
rarely used. No direct replacement exists. *Anything* is better than CGI
to interface a web server with a request handler.
* :class:`locale`: :func:`locale.getdefaultlocale` was deprecated in Python 3.11
and originally planned for removal in Python 3.13 (:gh:`90817`),
but removal has been postponed to Python 3.15.
Use :func:`locale.setlocale()`, :func:`locale.getencoding()` and
:func:`locale.getlocale()` instead.
(Contributed by Hugo van Kemenade in :gh:`111187`.)
* :class:`typing.NamedTuple`:
* The undocumented keyword argument syntax for creating NamedTuple classes
(``NT = NamedTuple("NT", x=int)``) is deprecated, and will be disallowed in
3.15. Use the class-based syntax or the functional syntax instead.
* When using the functional syntax to create a NamedTuple class, failing to
pass a value to the 'fields' parameter (``NT = NamedTuple("NT")``) is
deprecated. Passing ``None`` to the 'fields' parameter
(``NT = NamedTuple("NT", None)``) is also deprecated. Both will be
disallowed in Python 3.15. To create a NamedTuple class with 0 fields, use
``class NT(NamedTuple): pass`` or ``NT = NamedTuple("NT", [])``.
* :class:`typing.TypedDict`: When using the functional syntax to create a
TypedDict class, failing to pass a value to the 'fields' parameter (``TD =
TypedDict("TD")``) is deprecated. Passing ``None`` to the 'fields' parameter
(``TD = TypedDict("TD", None)``) is also deprecated. Both will be disallowed
in Python 3.15. To create a TypedDict class with 0 fields, use ``class
TD(TypedDict): pass`` or ``TD = TypedDict("TD", {})``.
* :mod:`wave`: Deprecate the ``getmark()``, ``setmark()`` and ``getmarkers()``
methods of the :class:`wave.Wave_read` and :class:`wave.Wave_write` classes.
They will be removed in Python 3.15.
(Contributed by Victor Stinner in :gh:`105096`.)
* Passing any arguments to :func:`threading.RLock` is now deprecated.
C version allows any numbers of args and kwargs,
but they are just ignored. Python version does not allow any arguments.
All arguments will be removed from :func:`threading.RLock` in Python 3.15.
(Contributed by Nikita Sobolev in :gh:`102029`.)
Pending Removal in Python 3.16
------------------------------
* :class:`array.array` ``'u'`` type (:c:type:`wchar_t`):
use the ``'w'`` type instead (``Py_UCS4``).
Pending Removal in Future Versions
----------------------------------
The following APIs were deprecated in earlier Python versions and will be removed,
although there is currently no date scheduled for their removal.
* :mod:`argparse`: Nesting argument groups and nesting mutually exclusive
groups are deprecated.
* :mod:`builtins`:
* ``~bool``, bitwise inversion on bool.
* ``bool(NotImplemented)``.
* Generators: ``throw(type, exc, tb)`` and ``athrow(type, exc, tb)``
signature is deprecated: use ``throw(exc)`` and ``athrow(exc)`` instead,
the single argument signature.
* Currently Python accepts numeric literals immediately followed by keywords,
for example ``0in x``, ``1or x``, ``0if 1else 2``. It allows confusing and
ambiguous expressions like ``[0x1for x in y]`` (which can be interpreted as
``[0x1 for x in y]`` or ``[0x1f or x in y]``). A syntax warning is raised
if the numeric literal is immediately followed by one of keywords
:keyword:`and`, :keyword:`else`, :keyword:`for`, :keyword:`if`,
:keyword:`in`, :keyword:`is` and :keyword:`or`. In a future release it
will be changed to a syntax error. (:gh:`87999`)
* Support for ``__index__()`` and ``__int__()`` method returning non-int type:
these methods will be required to return an instance of a strict subclass of
:class:`int`.
* Support for ``__float__()`` method returning a strict subclass of
:class:`float`: these methods will be required to return an instance of
:class:`float`.
* Support for ``__complex__()`` method returning a strict subclass of
:class:`complex`: these methods will be required to return an instance of
:class:`complex`.
* Delegation of ``int()`` to ``__trunc__()`` method.
* :mod:`calendar`: ``calendar.January`` and ``calendar.February`` constants are
deprecated and replaced by :data:`calendar.JANUARY` and
:data:`calendar.FEBRUARY`.
(Contributed by Prince Roshan in :gh:`103636`.)
* :mod:`datetime`:
* :meth:`~datetime.datetime.utcnow`:
use ``datetime.datetime.now(tz=datetime.UTC)``.
* :meth:`~datetime.datetime.utcfromtimestamp`:
use ``datetime.datetime.fromtimestamp(timestamp, tz=datetime.UTC)``.
* :mod:`gettext`: Plural value must be an integer.
* :mod:`importlib`:
* ``load_module()`` method: use ``exec_module()`` instead.
* :func:`~importlib.util.cache_from_source` *debug_override* parameter is
deprecated: use the *optimization* parameter instead.
* :mod:`importlib.metadata`:
* ``EntryPoints`` tuple interface.
* Implicit ``None`` on return values.
* :mod:`mailbox`: Use of StringIO input and text mode is deprecated, use
BytesIO and binary mode instead.
* :mod:`os`: Calling :func:`os.register_at_fork` in multi-threaded process.
* :class:`!pydoc.ErrorDuringImport`: A tuple value for *exc_info* parameter is
deprecated, use an exception instance.
* :mod:`re`: More strict rules are now applied for numerical group references
and group names in regular expressions. Only sequence of ASCII digits is now
accepted as a numerical reference. The group name in bytes patterns and
replacement strings can now only contain ASCII letters and digits and
underscore.
(Contributed by Serhiy Storchaka in :gh:`91760`.)
* :mod:`ssl` options and protocols:
* :class:`ssl.SSLContext` without protocol argument is deprecated.
* :class:`ssl.SSLContext`: :meth:`~ssl.SSLContext.set_npn_protocols` and
:meth:`!~ssl.SSLContext.selected_npn_protocol` are deprecated: use ALPN
instead.
* ``ssl.OP_NO_SSL*`` options
* ``ssl.OP_NO_TLS*`` options
* ``ssl.PROTOCOL_SSLv3``
* ``ssl.PROTOCOL_TLS``
* ``ssl.PROTOCOL_TLSv1``
* ``ssl.PROTOCOL_TLSv1_1``
* ``ssl.PROTOCOL_TLSv1_2``
* ``ssl.TLSVersion.SSLv3``
* ``ssl.TLSVersion.TLSv1``
* ``ssl.TLSVersion.TLSv1_1``
* :mod:`!sre_compile`, :mod:`!sre_constants` and :mod:`!sre_parse` modules.
* :attr:`~codeobject.co_lnotab`: use the ``co_lines`` attribute instead.
* :class:`typing.Text` (:gh:`92332`).
* :func:`sysconfig.is_python_build` *check_home* parameter is deprecated and
ignored.
* :mod:`threading` methods:
* :meth:`!threading.Condition.notifyAll`: use :meth:`~threading.Condition.notify_all`.
* :meth:`!threading.Event.isSet`: use :meth:`~threading.Event.is_set`.
* :meth:`!threading.Thread.isDaemon`, :meth:`threading.Thread.setDaemon`:
use :attr:`threading.Thread.daemon` attribute.
* :meth:`!threading.Thread.getName`, :meth:`threading.Thread.setName`:
use :attr:`threading.Thread.name` attribute.
* :meth:`!threading.currentThread`: use :meth:`threading.current_thread`.
* :meth:`!threading.activeCount`: use :meth:`threading.active_count`.
* :class:`unittest.IsolatedAsyncioTestCase`: it is deprecated to return a value
that is not None from a test case.
* :mod:`urllib.request`: :class:`~urllib.request.URLopener` and
:class:`~urllib.request.FancyURLopener` style of invoking requests is
deprecated. Use newer :func:`~urllib.request.urlopen` functions and methods.
* :func:`!urllib.parse.to_bytes`.
* :mod:`urllib.parse` deprecated functions: :func:`~urllib.parse.urlparse` instead
* ``splitattr()``
* ``splithost()``
* ``splitnport()``
* ``splitpasswd()``
* ``splitport()``
* ``splitquery()``
* ``splittag()``
* ``splittype()``
* ``splituser()``
* ``splitvalue()``
* :mod:`wsgiref`: ``SimpleHandler.stdout.write()`` should not do partial
writes.
* :meth:`zipimport.zipimporter.load_module` is deprecated:
use :meth:`~zipimport.zipimporter.exec_module` instead.
Removed
=======
.. _whatsnew313-pep594:
PEP 594: dead batteries
-----------------------
* :pep:`594` removed 19 modules from the standard library,
deprecated in Python 3.11:
* :mod:`!aifc`.
(Contributed by Victor Stinner in :gh:`104773`.)
* :mod:`!audioop`.
(Contributed by Victor Stinner in :gh:`104773`.)
* :mod:`!chunk`.
(Contributed by Victor Stinner in :gh:`104773`.)
* :mod:`!cgi` and :mod:`!cgitb`.
* ``cgi.FieldStorage`` can typically be replaced with
:func:`urllib.parse.parse_qsl` for ``GET`` and ``HEAD`` requests,
and the :mod:`email.message` module or `multipart
<https://pypi.org/project/multipart/>`__ PyPI project for ``POST`` and
``PUT``.
* ``cgi.parse()`` can be replaced by calling :func:`urllib.parse.parse_qs`
directly on the desired query string, except for ``multipart/form-data``
input, which can be handled as described for ``cgi.parse_multipart()``.
* ``cgi.parse_header()`` can be replaced with the functionality in the
:mod:`email` package, which implements the same MIME RFCs. For example,
with :class:`email.message.EmailMessage`::
from email.message import EmailMessage
msg = EmailMessage()
msg['content-type'] = 'application/json; charset="utf8"'
main, params = msg.get_content_type(), msg['content-type'].params
* ``cgi.parse_multipart()`` can be replaced with the functionality in the
:mod:`email` package (e.g. :class:`email.message.EmailMessage` and
:class:`email.message.Message`) which implements the same MIME RFCs, or
with the `multipart <https://pypi.org/project/multipart/>`__ PyPI project.
(Contributed by Victor Stinner in :gh:`104773`.)
* :mod:`!crypt` module and its private :mod:`!_crypt` extension.
The :mod:`hashlib` module is a potential replacement for certain use cases.
Otherwise, the following PyPI projects can be used:
* `bcrypt <https://pypi.org/project/bcrypt/>`_:
Modern password hashing for your software and your servers.
* `passlib <https://pypi.org/project/passlib/>`_:
Comprehensive password hashing framework supporting over 30 schemes.
* `argon2-cffi <https://pypi.org/project/argon2-cffi/>`_:
The secure Argon2 password hashing algorithm.
* `legacycrypt <https://pypi.org/project/legacycrypt/>`_:
Wrapper to the POSIX crypt library call and associated functionality.
(Contributed by Victor Stinner in :gh:`104773`.)
* :mod:`!imghdr`: use the projects
`filetype <https://pypi.org/project/filetype/>`_,
`puremagic <https://pypi.org/project/puremagic/>`_,
or `python-magic <https://pypi.org/project/python-magic/>`_ instead.
(Contributed by Victor Stinner in :gh:`104773`.)
* :mod:`!mailcap`.
The :mod:`mimetypes` module provides an alternative.
(Contributed by Victor Stinner in :gh:`104773`.)
* :mod:`!msilib`.
(Contributed by Zachary Ware in :gh:`104773`.)
* :mod:`!nis`.
(Contributed by Victor Stinner in :gh:`104773`.)
* :mod:`!nntplib`:
the `PyPI nntplib project <https://pypi.org/project/nntplib/>`_
can be used instead.
(Contributed by Victor Stinner in :gh:`104773`.)
* :mod:`!ossaudiodev`: use the
`pygame project <https://www.pygame.org/>`_ for audio playback.
(Contributed by Victor Stinner in :gh:`104780`.)
* :mod:`!pipes`: use the :mod:`subprocess` module instead.
(Contributed by Victor Stinner in :gh:`104773`.)
* :mod:`!sndhdr`: use the projects
`filetype <https://pypi.org/project/filetype/>`_,
`puremagic <https://pypi.org/project/puremagic/>`_, or
`python-magic <https://pypi.org/project/python-magic/>`_ instead.
(Contributed by Victor Stinner in :gh:`104773`.)
* :mod:`!spwd`:
the `python-pam project <https://pypi.org/project/python-pam/>`_
can be used instead.
(Contributed by Victor Stinner in :gh:`104773`.)
* :mod:`!sunau`.
(Contributed by Victor Stinner in :gh:`104773`.)
* :mod:`!telnetlib`, use the projects
`telnetlib3 <https://pypi.org/project/telnetlib3/>`_ or
`Exscript <https://pypi.org/project/Exscript/>`_ instead.
(Contributed by Victor Stinner in :gh:`104773`.)
* :mod:`!uu`: the :mod:`base64` module is a modern alternative.
(Contributed by Victor Stinner in :gh:`104773`.)
* :mod:`!xdrlib`.
(Contributed by Victor Stinner in :gh:`104773`.)
2to3
----
* Remove the ``2to3`` program and the :mod:`!lib2to3` module,
deprecated in Python 3.11.
(Contributed by Victor Stinner in :gh:`104780`.)
configparser
------------
* Remove the undocumented :class:`!configparser.LegacyInterpolation` class,
deprecated in the docstring since Python 3.2,
and with a deprecation warning since Python 3.11.
(Contributed by Hugo van Kemenade in :gh:`104886`.)
importlib
---------
* Remove :mod:`importlib.resources` deprecated methods:
* ``contents()``
* ``is_resource()``
* ``open_binary()``
* ``open_text()``
* ``path()``
* ``read_binary()``
* ``read_text()``
Use :func:`importlib.resources.files()` instead. Refer to `importlib-resources: Migrating from Legacy
<https://importlib-resources.readthedocs.io/en/latest/using.html#migrating-from-legacy>`_
for migration advice.
(Contributed by Jason R. Coombs in :gh:`106532`.)
locale
------
* Remove ``locale.resetlocale()`` function deprecated in Python 3.11:
use ``locale.setlocale(locale.LC_ALL, "")`` instead.
(Contributed by Victor Stinner in :gh:`104783`.)
logging
-------
* :mod:`logging`: Remove undocumented and untested ``Logger.warn()`` and
``LoggerAdapter.warn()`` methods and ``logging.warn()`` function. Deprecated
since Python 3.3, they were aliases to the :meth:`logging.Logger.warning`
method, :meth:`!logging.LoggerAdapter.warning` method and
:func:`logging.warning` function.
(Contributed by Victor Stinner in :gh:`105376`.)
pathlib
-------
* Remove support for using :class:`pathlib.Path` objects as context managers.
This functionality was deprecated and made a no-op in Python 3.9.
re
--
* Remove undocumented, never working, and deprecated ``re.template`` function
and ``re.TEMPLATE`` flag (and ``re.T`` alias).
(Contributed by Serhiy Storchaka and Nikita Sobolev in :gh:`105687`.)
tkinter
-------
* Remove the :mod:`!tkinter.tix` module, deprecated in Python 3.6. The
third-party Tix library which the module wrapped is unmaintained.
(Contributed by Zachary Ware in :gh:`75552`.)
turtle
------
* Remove the :meth:`!turtle.RawTurtle.settiltangle` method,
deprecated in docs since Python 3.1
and with a deprecation warning since Python 3.11.
(Contributed by Hugo van Kemenade in :gh:`104876`.)
typing
------
* Namespaces ``typing.io`` and ``typing.re``, deprecated in Python 3.8,
are now removed. The items in those namespaces can be imported directly
from :mod:`typing`. (Contributed by Sebastian Rittau in :gh:`92871`.)
* Remove support for the keyword-argument method of creating
:class:`typing.TypedDict` types, deprecated in Python 3.11.
(Contributed by Tomas Roun in :gh:`104786`.)
unittest
--------
* Removed the following :mod:`unittest` functions, deprecated in Python 3.11:
* :func:`!unittest.findTestCases`
* :func:`!unittest.makeSuite`
* :func:`!unittest.getTestCaseNames`
Use :class:`~unittest.TestLoader` methods instead:
* :meth:`unittest.TestLoader.loadTestsFromModule`
* :meth:`unittest.TestLoader.loadTestsFromTestCase`
* :meth:`unittest.TestLoader.getTestCaseNames`
(Contributed by Hugo van Kemenade in :gh:`104835`.)
* Remove the untested and undocumented :meth:`!unittest.TestProgram.usageExit`
method, deprecated in Python 3.11.
(Contributed by Hugo van Kemenade in :gh:`104992`.)
urllib
------
* Remove *cafile*, *capath* and *cadefault* parameters of the
:func:`urllib.request.urlopen` function, deprecated in Python 3.6: use the
*context* parameter instead. Please use
:meth:`ssl.SSLContext.load_cert_chain` instead, or let
:func:`ssl.create_default_context` select the system's trusted CA
certificates for you.
(Contributed by Victor Stinner in :gh:`105382`.)
webbrowser
----------
* Remove the untested and undocumented :mod:`webbrowser` :class:`!MacOSX` class,
deprecated in Python 3.11.
Use the :class:`!MacOSXOSAScript` class (introduced in Python 3.2) instead.
(Contributed by Hugo van Kemenade in :gh:`104804`.)
* Remove deprecated ``webbrowser.MacOSXOSAScript._name`` attribute.
Use :attr:`webbrowser.MacOSXOSAScript.name <webbrowser.controller.name>`
attribute instead.
(Contributed by Nikita Sobolev in :gh:`105546`.)
Others
------
* None yet
CPython bytecode changes
========================
* The oparg of ``YIELD_VALUE`` is now ``1`` if the yield is part of a
yield-from or await, and ``0`` otherwise. The oparg of ``RESUME`` was
changed to add a bit indicating whether the except-depth is 1, which
is needed to optimize closing of generators.
(Contributed by Irit Katriel in :gh:`111354`.)
Porting to Python 3.13
======================
This section lists previously described changes and other bugfixes
that may require changes to your code.
Changes in the Python API
-------------------------
* :meth:`!tkinter.Text.count` now always returns an integer if one or less
counting options are specified.
Previously it could return a single count as a 1-tuple, an integer (only if
option ``"update"`` was specified) or ``None`` if no items found.
The result is now the same if ``wantobjects`` is set to ``0``.
(Contributed by Serhiy Storchaka in :gh:`97928`.)
* Functions :c:func:`PyDict_GetItem`, :c:func:`PyDict_GetItemString`,
:c:func:`PyMapping_HasKey`, :c:func:`PyMapping_HasKeyString`,
:c:func:`PyObject_HasAttr`, :c:func:`PyObject_HasAttrString`, and
:c:func:`PySys_GetObject`, which clear all errors occurred during calling
the function, report now them using :func:`sys.unraisablehook`.
You can consider to replace these functions with other functions as
recomended in the documentation.
(Contributed by Serhiy Storchaka in :gh:`106672`.)
* An :exc:`OSError` is now raised by :func:`getpass.getuser` for any failure to
retrieve a username, instead of :exc:`ImportError` on non-Unix platforms or
:exc:`KeyError` on Unix platforms where the password database is empty.
* The :mod:`threading` module now expects the :mod:`!_thread` module to have
an ``_is_main_interpreter`` attribute. It is a function with no
arguments that returns ``True`` if the current interpreter is the
main interpreter.
Any library or application that provides a custom ``_thread`` module
must provide ``_is_main_interpreter()``, just like the module's
other "private" attributes.
(See :gh:`112826`.)
Build Changes
=============
* Autoconf 2.71 and aclocal 1.16.4 is now required to regenerate
the :file:`configure` script.
(Contributed by Christian Heimes in :gh:`89886`.)
* SQLite 3.15.2 or newer is required to build the :mod:`sqlite3` extension module.
(Contributed by Erlend Aasland in :gh:`105875`.)
* Python built with :file:`configure` :option:`--with-trace-refs` (tracing
references) is now ABI compatible with Python release build and
:ref:`debug build <debug-build>`.
(Contributed by Victor Stinner in :gh:`108634`.)
* Building CPython now requires a compiler with support for the C11 atomic
library, GCC built-in atomic functions, or MSVC interlocked intrinsics.
* The ``errno``, ``md5``, ``resource``, ``winsound``, ``_ctypes_test``,
``_multiprocessing.posixshmem``, ``_scproxy``, ``_stat``,
``_testimportmultiple`` and ``_uuid`` C extensions are now built with the
:ref:`limited C API <limited-c-api>`.
(Contributed by Victor Stinner in :gh:`85283`.)
C API Changes
=============
New Features
------------
* You no longer have to define the ``PY_SSIZE_T_CLEAN`` macro before including
:file:`Python.h` when using ``#`` formats in
:ref:`format codes <arg-parsing-string-and-buffers>`.
APIs accepting the format codes always use ``Py_ssize_t`` for ``#`` formats.
(Contributed by Inada Naoki in :gh:`104922`.)
* The *keywords* parameter of :c:func:`PyArg_ParseTupleAndKeywords` and
:c:func:`PyArg_VaParseTupleAndKeywords` has now type :c:expr:`char * const *`
in C and :c:expr:`const char * const *` in C++, instead of :c:expr:`char **`.
It makes these functions compatible with arguments of type
:c:expr:`const char * const *`, :c:expr:`const char **` or
:c:expr:`char * const *` in C++ and :c:expr:`char * const *` in C
without an explicit type cast.
This can be overridden with the :c:macro:`PY_CXX_CONST` macro.
(Contributed by Serhiy Storchaka in :gh:`65210`.)
* Add :c:func:`PyImport_AddModuleRef`: similar to
:c:func:`PyImport_AddModule`, but return a :term:`strong reference` instead
of a :term:`borrowed reference`.
(Contributed by Victor Stinner in :gh:`105922`.)
* Add :c:func:`PyWeakref_GetRef` function: similar to
:c:func:`PyWeakref_GetObject` but returns a :term:`strong reference`, or
``NULL`` if the referent is no longer live.
(Contributed by Victor Stinner in :gh:`105927`.)
* Add :c:func:`PyObject_GetOptionalAttr` and
:c:func:`PyObject_GetOptionalAttrString`, variants of
:c:func:`PyObject_GetAttr` and :c:func:`PyObject_GetAttrString` which
don't raise :exc:`AttributeError` if the attribute is not found.
These variants are more convenient and faster if the missing attribute
should not be treated as a failure.
(Contributed by Serhiy Storchaka in :gh:`106521`.)
* Add :c:func:`PyMapping_GetOptionalItem` and
:c:func:`PyMapping_GetOptionalItemString`: variants of
:c:func:`PyObject_GetItem` and :c:func:`PyMapping_GetItemString` which don't
raise :exc:`KeyError` if the key is not found.
These variants are more convenient and faster if the missing key should not
be treated as a failure.
(Contributed by Serhiy Storchaka in :gh:`106307`.)
* Add fixed variants of functions which silently ignore errors:
- :c:func:`PyObject_HasAttrWithError` replaces :c:func:`PyObject_HasAttr`.
- :c:func:`PyObject_HasAttrStringWithError` replaces :c:func:`PyObject_HasAttrString`.
- :c:func:`PyMapping_HasKeyWithError` replaces :c:func:`PyMapping_HasKey`.
- :c:func:`PyMapping_HasKeyStringWithError` replaces :c:func:`PyMapping_HasKeyString`.
New functions return not only ``1`` for true and ``0`` for false, but also
``-1`` for error.
(Contributed by Serhiy Storchaka in :gh:`108511`.)
* If Python is built in :ref:`debug mode <debug-build>` or :option:`with
assertions <--with-assertions>`, :c:func:`PyTuple_SET_ITEM` and
:c:func:`PyList_SET_ITEM` now check the index argument with an assertion.
(Contributed by Victor Stinner in :gh:`106168`.)
* Add :c:func:`PyModule_Add` function: similar to
:c:func:`PyModule_AddObjectRef` and :c:func:`PyModule_AddObject` but
always steals a reference to the value.
(Contributed by Serhiy Storchaka in :gh:`86493`.)
* Added :c:func:`PyDict_GetItemRef` and :c:func:`PyDict_GetItemStringRef`
functions: similar to :c:func:`PyDict_GetItemWithError` but returning a
:term:`strong reference` instead of a :term:`borrowed reference`. Moreover,
these functions return -1 on error and so checking ``PyErr_Occurred()`` is
not needed.
(Contributed by Victor Stinner in :gh:`106004`.)
* Added :c:func:`PyDict_ContainsString` function: same as
:c:func:`PyDict_Contains`, but *key* is specified as a :c:expr:`const char*`
UTF-8 encoded bytes string, rather than a :c:expr:`PyObject*`.
(Contributed by Victor Stinner in :gh:`108314`.)
* Add :c:func:`Py_IsFinalizing` function: check if the main Python interpreter is
:term:`shutting down <interpreter shutdown>`.
(Contributed by Victor Stinner in :gh:`108014`.)
* Add :c:func:`PyLong_AsInt` function: similar to :c:func:`PyLong_AsLong`, but
store the result in a C :c:expr:`int` instead of a C :c:expr:`long`.
Previously, it was known as the private function :c:func:`!_PyLong_AsInt`
(with an underscore prefix).
(Contributed by Victor Stinner in :gh:`108014`.)
* Python built with :file:`configure` :option:`--with-trace-refs` (tracing
references) now supports the :ref:`Limited API <limited-c-api>`.
(Contributed by Victor Stinner in :gh:`108634`.)
* Add :c:func:`PyObject_VisitManagedDict` and
:c:func:`PyObject_ClearManagedDict` functions which must be called by the
traverse and clear functions of a type using
:c:macro:`Py_TPFLAGS_MANAGED_DICT` flag. The `pythoncapi-compat project
<https://github.com/python/pythoncapi-compat/>`__ can be used to get these
functions on Python 3.11 and 3.12.
(Contributed by Victor Stinner in :gh:`107073`.)
* Add :c:func:`PyUnicode_EqualToUTF8AndSize` and :c:func:`PyUnicode_EqualToUTF8`
functions: compare Unicode object with a :c:expr:`const char*` UTF-8 encoded
string and return true (``1``) if they are equal, or false (``0``) otherwise.
These functions do not raise exceptions.
(Contributed by Serhiy Storchaka in :gh:`110289`.)
* Add :c:func:`PyThreadState_GetUnchecked()` function: similar to
:c:func:`PyThreadState_Get()`, but don't kill the process with a fatal error
if it is NULL. The caller is responsible to check if the result is NULL.
Previously, the function was private and known as
``_PyThreadState_UncheckedGet()``.
(Contributed by Victor Stinner in :gh:`108867`.)
* Add :c:func:`PySys_AuditTuple` function: similar to :c:func:`PySys_Audit`,
but pass event arguments as a Python :class:`tuple` object.
(Contributed by Victor Stinner in :gh:`85283`.)
* :c:func:`PyArg_ParseTupleAndKeywords` now supports non-ASCII keyword
parameter names.
(Contributed by Serhiy Storchaka in :gh:`110815`.)
* Add :c:func:`PyMem_RawMalloc`, :c:func:`PyMem_RawCalloc`,
:c:func:`PyMem_RawRealloc` and :c:func:`PyMem_RawFree` to the limited C API
(version 3.13).
(Contributed by Victor Stinner in :gh:`85283`.)
* Add :c:func:`PySys_Audit` and :c:func:`PySys_AuditTuple` functions to the
limited C API.
(Contributed by Victor Stinner in :gh:`85283`.)
* Add :c:func:`PyErr_FormatUnraisable` function: similar to
:c:func:`PyErr_WriteUnraisable`, but allow to customize the warning mesage.
(Contributed by Serhiy Storchaka in :gh:`108082`.)
* Add :c:func:`PyList_Extend` and :c:func:`PyList_Clear` functions: similar to
Python ``list.extend()`` and ``list.clear()`` methods.
(Contributed by Victor Stinner in :gh:`111138`.)
* Add :c:func:`PyDict_Pop` and :c:func:`PyDict_PopString` functions: remove a
key from a dictionary and optionally return the removed value. This is
similar to :meth:`dict.pop`, but without the default value and not raising
:exc:`KeyError` if the key missing.
(Contributed by Stefan Behnel and Victor Stinner in :gh:`111262`.)
* Add :c:func:`Py_HashPointer` function to hash a pointer.
(Contributed by Victor Stinner in :gh:`111545`.)
Porting to Python 3.13
----------------------
* ``Python.h`` no longer includes the ``<ieeefp.h>`` standard header. It was
included for the ``finite()`` function which is now provided by the
``<math.h>`` header. It should now be included explicitly if needed. Remove
also the ``HAVE_IEEEFP_H`` macro.
(Contributed by Victor Stinner in :gh:`108765`.)
* ``Python.h`` no longer includes these standard header files: ``<time.h>``,
``<sys/select.h>`` and ``<sys/time.h>``. If needed, they should now be
included explicitly. For example, ``<time.h>`` provides the ``clock()`` and
``gmtime()`` functions, ``<sys/select.h>`` provides the ``select()``
function, and ``<sys/time.h>`` provides the ``futimes()``, ``gettimeofday()``
and ``setitimer()`` functions.
(Contributed by Victor Stinner in :gh:`108765`.)
* If the :c:macro:`Py_LIMITED_API` macro is defined, :c:macro:`!Py_BUILD_CORE`,
:c:macro:`!Py_BUILD_CORE_BUILTIN` and :c:macro:`!Py_BUILD_CORE_MODULE` macros
are now undefined by ``<Python.h>``.
(Contributed by Victor Stinner in :gh:`85283`.)
* The old trashcan macros ``Py_TRASHCAN_SAFE_BEGIN`` and ``Py_TRASHCAN_SAFE_END``
were removed. They should be replaced by the new macros ``Py_TRASHCAN_BEGIN``
and ``Py_TRASHCAN_END``.
A tp_dealloc function that has the old macros, such as::
static void
mytype_dealloc(mytype *p)
{
PyObject_GC_UnTrack(p);
Py_TRASHCAN_SAFE_BEGIN(p);
...
Py_TRASHCAN_SAFE_END
}
should migrate to the new macros as follows::
static void
mytype_dealloc(mytype *p)
{
PyObject_GC_UnTrack(p);
Py_TRASHCAN_BEGIN(p, mytype_dealloc)
...
Py_TRASHCAN_END
}
Note that ``Py_TRASHCAN_BEGIN`` has a second argument which
should be the deallocation function it is in.
* On Windows, ``Python.h`` no longer includes the ``<stddef.h>`` standard
header file. If needed, it should now be included explicitly. For example, it
provides ``offsetof()`` function, and ``size_t`` and ``ptrdiff_t`` types.
Including ``<stddef.h>`` explicitly was already needed by all other
platforms, the ``HAVE_STDDEF_H`` macro is only defined on Windows.
(Contributed by Victor Stinner in :gh:`108765`.)
Deprecated
----------
* Passing optional arguments *maxsplit*, *count* and *flags* in module-level
functions :func:`re.split`, :func:`re.sub` and :func:`re.subn` as positional
arguments is now deprecated.
In future Python versions these parameters will be
:ref:`keyword-only <keyword-only_parameter>`.
(Contributed by Serhiy Storchaka in :gh:`56166`.)
* Deprecate the old ``Py_UNICODE`` and ``PY_UNICODE_TYPE`` types: use directly
the :c:type:`wchar_t` type instead. Since Python 3.3, ``Py_UNICODE`` and
``PY_UNICODE_TYPE`` are just aliases to :c:type:`wchar_t`.
(Contributed by Victor Stinner in :gh:`105156`.)
* Deprecate old Python initialization functions:
* :c:func:`PySys_ResetWarnOptions`:
clear :data:`sys.warnoptions` and :data:`!warnings.filters` instead.
* :c:func:`Py_GetExecPrefix`: get :data:`sys.exec_prefix` instead.
* :c:func:`Py_GetPath`: get :data:`sys.path` instead.
* :c:func:`Py_GetPrefix`: get :data:`sys.prefix` instead.
* :c:func:`Py_GetProgramFullPath`: get :data:`sys.executable` instead.
* :c:func:`Py_GetProgramName`: get :data:`sys.executable` instead.
* :c:func:`Py_GetPythonHome`: get :c:member:`PyConfig.home` or
:envvar:`PYTHONHOME` environment variable instead.
Functions scheduled for removal in Python 3.15.
(Contributed by Victor Stinner in :gh:`105145`.)
* Deprecate the :c:func:`PyImport_ImportModuleNoBlock` function which is just
an alias to :c:func:`PyImport_ImportModule` since Python 3.3.
Scheduled for removal in Python 3.15.
(Contributed by Victor Stinner in :gh:`105396`.)
* Deprecate the :c:func:`PyWeakref_GetObject` and
:c:func:`PyWeakref_GET_OBJECT` functions, which return a :term:`borrowed
reference`: use the new :c:func:`PyWeakref_GetRef` function instead, it
returns a :term:`strong reference`. The `pythoncapi-compat project
<https://github.com/python/pythoncapi-compat/>`__ can be used to get
:c:func:`PyWeakref_GetRef` on Python 3.12 and older.
(Contributed by Victor Stinner in :gh:`105927`.)
Removed
-------
* Removed chained :class:`classmethod` descriptors (introduced in
:issue:`19072`). This can no longer be used to wrap other descriptors
such as :class:`property`. The core design of this feature was flawed
and caused a number of downstream problems. To "pass-through" a
:class:`classmethod`, consider using the :attr:`!__wrapped__`
attribute that was added in Python 3.10. (Contributed by Raymond
Hettinger in :gh:`89519`.)
* Remove many APIs (functions, macros, variables) with names prefixed by
``_Py`` or ``_PY`` (considered as private API). If your project is affected
by one of these removals and you consider that the removed API should remain
available, please open a new issue to request a public C API and
add ``cc @vstinner`` to the issue to notify Victor Stinner.
(Contributed by Victor Stinner in :gh:`106320`.)
* Remove functions deprecated in Python 3.9.
* ``PyEval_CallObject()``, ``PyEval_CallObjectWithKeywords()``: use
:c:func:`PyObject_CallNoArgs` or :c:func:`PyObject_Call` instead.
Warning: :c:func:`PyObject_Call` positional arguments must be a
:class:`tuple` and must not be *NULL*, keyword arguments must be a
:class:`dict` or *NULL*, whereas removed functions checked arguments type
and accepted *NULL* positional and keyword arguments.
To replace ``PyEval_CallObjectWithKeywords(func, NULL, kwargs)`` with
:c:func:`PyObject_Call`, pass an empty tuple as positional arguments using
:c:func:`PyTuple_New(0) <PyTuple_New>`.
* ``PyEval_CallFunction()``: use :c:func:`PyObject_CallFunction` instead.
* ``PyEval_CallMethod()``: use :c:func:`PyObject_CallMethod` instead.
* ``PyCFunction_Call()``: use :c:func:`PyObject_Call` instead.
(Contributed by Victor Stinner in :gh:`105107`.)
* Remove old buffer protocols deprecated in Python 3.0. Use :ref:`bufferobjects` instead.
* :c:func:`!PyObject_CheckReadBuffer`: Use :c:func:`PyObject_CheckBuffer` to
test if the object supports the buffer protocol.
Note that :c:func:`PyObject_CheckBuffer` doesn't guarantee that
:c:func:`PyObject_GetBuffer` will succeed.
To test if the object is actually readable, see the next example
of :c:func:`PyObject_GetBuffer`.
* :c:func:`!PyObject_AsCharBuffer`, :c:func:`!PyObject_AsReadBuffer`:
:c:func:`PyObject_GetBuffer` and :c:func:`PyBuffer_Release` instead:
.. code-block:: c
Py_buffer view;
if (PyObject_GetBuffer(obj, &view, PyBUF_SIMPLE) < 0) {
return NULL;
}
// Use `view.buf` and `view.len` to read from the buffer.
// You may need to cast buf as `(const char*)view.buf`.
PyBuffer_Release(&view);
* :c:func:`!PyObject_AsWriteBuffer`: Use
:c:func:`PyObject_GetBuffer` and :c:func:`PyBuffer_Release` instead:
.. code-block:: c
Py_buffer view;
if (PyObject_GetBuffer(obj, &view, PyBUF_WRITABLE) < 0) {
return NULL;
}
// Use `view.buf` and `view.len` to write to the buffer.
PyBuffer_Release(&view);
(Contributed by Inada Naoki in :gh:`85275`.)
* Remove the following old functions to configure the Python initialization,
deprecated in Python 3.11:
* ``PySys_AddWarnOptionUnicode()``: use :c:member:`PyConfig.warnoptions` instead.
* ``PySys_AddWarnOption()``: use :c:member:`PyConfig.warnoptions` instead.
* ``PySys_AddXOption()``: use :c:member:`PyConfig.xoptions` instead.
* ``PySys_HasWarnOptions()``: use :c:member:`PyConfig.xoptions` instead.
* ``PySys_SetArgvEx()``: set :c:member:`PyConfig.argv` instead.
* ``PySys_SetArgv()``: set :c:member:`PyConfig.argv` instead.
* ``PySys_SetPath()``: set :c:member:`PyConfig.module_search_paths` instead.
* ``Py_SetPath()``: set :c:member:`PyConfig.module_search_paths` instead.
* ``Py_SetProgramName()``: set :c:member:`PyConfig.program_name` instead.
* ``Py_SetPythonHome()``: set :c:member:`PyConfig.home` instead.
* ``Py_SetStandardStreamEncoding()``: set :c:member:`PyConfig.stdio_encoding`
instead, and set also maybe :c:member:`PyConfig.legacy_windows_stdio` (on
Windows).
* ``_Py_SetProgramFullPath()``: set :c:member:`PyConfig.executable` instead.
Use the new :c:type:`PyConfig` API of the :ref:`Python Initialization
Configuration <init-config>` instead (:pep:`587`), added to Python 3.8.
(Contributed by Victor Stinner in :gh:`105145`.)
* Remove the old trashcan macros ``Py_TRASHCAN_SAFE_BEGIN`` and
``Py_TRASHCAN_SAFE_END``. They should be replaced by the new macros
``Py_TRASHCAN_BEGIN`` and ``Py_TRASHCAN_END``. The new macros were
added in Python 3.8 and the old macros were deprecated in Python 3.11.
(Contributed by Irit Katriel in :gh:`105111`.)
* Remove ``PyEval_InitThreads()`` and ``PyEval_ThreadsInitialized()``
functions, deprecated in Python 3.9. Since Python 3.7, ``Py_Initialize()``
always creates the GIL: calling ``PyEval_InitThreads()`` did nothing and
``PyEval_ThreadsInitialized()`` always returned non-zero.
(Contributed by Victor Stinner in :gh:`105182`.)
* Remove ``PyEval_AcquireLock()`` and ``PyEval_ReleaseLock()`` functions,
deprecated in Python 3.2. They didn't update the current thread state.
They can be replaced with:
* :c:func:`PyEval_SaveThread` and :c:func:`PyEval_RestoreThread`;
* low-level :c:func:`PyEval_AcquireThread` and :c:func:`PyEval_RestoreThread`;
* or :c:func:`PyGILState_Ensure` and :c:func:`PyGILState_Release`.
(Contributed by Victor Stinner in :gh:`105182`.)
* Remove private ``_PyObject_FastCall()`` function:
use ``PyObject_Vectorcall()`` which is available since Python 3.8
(:pep:`590`).
(Contributed by Victor Stinner in :gh:`106023`.)
* Remove ``cpython/pytime.h`` header file: it only contained private functions.
(Contributed by Victor Stinner in :gh:`106316`.)
* Remove ``_PyInterpreterState_Get()`` alias to
:c:func:`PyInterpreterState_Get()` which was kept for backward compatibility
with Python 3.8. The `pythoncapi-compat project
<https://github.com/python/pythoncapi-compat/>`__ can be used to get
:c:func:`PyInterpreterState_Get()` on Python 3.8 and older.
(Contributed by Victor Stinner in :gh:`106320`.)
* The :c:func:`PyModule_AddObject` function is now :term:`soft deprecated`:
:c:func:`PyModule_Add` or :c:func:`PyModule_AddObjectRef` functions should
be used instead.
(Contributed by Serhiy Storchaka in :gh:`86493`.)
Pending Removal in Python 3.14
------------------------------
* Creating immutable types (:c:macro:`Py_TPFLAGS_IMMUTABLETYPE`) with mutable
bases using the C API.
* Global configuration variables:
* :c:var:`Py_DebugFlag`: use :c:member:`PyConfig.parser_debug`
* :c:var:`Py_VerboseFlag`: use :c:member:`PyConfig.verbose`
* :c:var:`Py_QuietFlag`: use :c:member:`PyConfig.quiet`
* :c:var:`Py_InteractiveFlag`: use :c:member:`PyConfig.interactive`
* :c:var:`Py_InspectFlag`: use :c:member:`PyConfig.inspect`
* :c:var:`Py_OptimizeFlag`: use :c:member:`PyConfig.optimization_level`
* :c:var:`Py_NoSiteFlag`: use :c:member:`PyConfig.site_import`
* :c:var:`Py_BytesWarningFlag`: use :c:member:`PyConfig.bytes_warning`
* :c:var:`Py_FrozenFlag`: use :c:member:`PyConfig.pathconfig_warnings`
* :c:var:`Py_IgnoreEnvironmentFlag`: use :c:member:`PyConfig.use_environment`
* :c:var:`Py_DontWriteBytecodeFlag`: use :c:member:`PyConfig.write_bytecode`
* :c:var:`Py_NoUserSiteDirectory`: use :c:member:`PyConfig.user_site_directory`
* :c:var:`Py_UnbufferedStdioFlag`: use :c:member:`PyConfig.buffered_stdio`
* :c:var:`Py_HashRandomizationFlag`: use :c:member:`PyConfig.use_hash_seed`
and :c:member:`PyConfig.hash_seed`
* :c:var:`Py_IsolatedFlag`: use :c:member:`PyConfig.isolated`
* :c:var:`Py_LegacyWindowsFSEncodingFlag`: use :c:member:`PyPreConfig.legacy_windows_fs_encoding`
* :c:var:`Py_LegacyWindowsStdioFlag`: use :c:member:`PyConfig.legacy_windows_stdio`
* :c:var:`!Py_FileSystemDefaultEncoding`: use :c:member:`PyConfig.filesystem_encoding`
* :c:var:`!Py_HasFileSystemDefaultEncoding`: use :c:member:`PyConfig.filesystem_encoding`
* :c:var:`!Py_FileSystemDefaultEncodeErrors`: use :c:member:`PyConfig.filesystem_errors`
* :c:var:`!Py_UTF8Mode`: use :c:member:`PyPreConfig.utf8_mode` (see :c:func:`Py_PreInitialize`)
The :c:func:`Py_InitializeFromConfig` API should be used with
:c:type:`PyConfig` instead.
Pending Removal in Python 3.15
------------------------------
* :c:func:`PyImport_ImportModuleNoBlock`: use :c:func:`PyImport_ImportModule`.
* :c:func:`PyWeakref_GET_OBJECT`: use :c:func:`PyWeakref_GetRef` instead.
* :c:func:`PyWeakref_GetObject`: use :c:func:`PyWeakref_GetRef` instead.
* :c:type:`!Py_UNICODE_WIDE` type: use :c:type:`wchar_t` instead.
* :c:type:`Py_UNICODE` type: use :c:type:`wchar_t` instead.
* Python initialization functions:
* :c:func:`PySys_ResetWarnOptions`: clear :data:`sys.warnoptions` and
:data:`!warnings.filters` instead.
* :c:func:`Py_GetExecPrefix`: get :data:`sys.exec_prefix` instead.
* :c:func:`Py_GetPath`: get :data:`sys.path` instead.
* :c:func:`Py_GetPrefix`: get :data:`sys.prefix` instead.
* :c:func:`Py_GetProgramFullPath`: get :data:`sys.executable` instead.
* :c:func:`Py_GetProgramName`: get :data:`sys.executable` instead.
* :c:func:`Py_GetPythonHome`: get :c:member:`PyConfig.home` or
:envvar:`PYTHONHOME` environment variable instead.
Pending Removal in Future Versions
----------------------------------
The following APIs were deprecated in earlier Python versions and will be
removed, although there is currently no date scheduled for their removal.
* :c:macro:`Py_TPFLAGS_HAVE_FINALIZE`: no needed since Python 3.8.
* :c:func:`PyErr_Fetch`: use :c:func:`PyErr_GetRaisedException`.
* :c:func:`PyErr_NormalizeException`: use :c:func:`PyErr_GetRaisedException`.
* :c:func:`PyErr_Restore`: use :c:func:`PyErr_SetRaisedException`.
* :c:func:`PyModule_GetFilename`: use :c:func:`PyModule_GetFilenameObject`.
* :c:func:`PyOS_AfterFork`: use :c:func:`PyOS_AfterFork_Child()`.
* :c:func:`PySlice_GetIndicesEx`.
* :c:func:`!PyUnicode_AsDecodedObject`.
* :c:func:`!PyUnicode_AsDecodedUnicode`.
* :c:func:`!PyUnicode_AsEncodedObject`.
* :c:func:`!PyUnicode_AsEncodedUnicode`.
* :c:func:`PyUnicode_READY`: not needed since Python 3.12.
* :c:func:`!_PyErr_ChainExceptions`.
* :c:member:`!PyBytesObject.ob_shash` member:
call :c:func:`PyObject_Hash` instead.
* :c:member:`!PyDictObject.ma_version_tag` member.
* TLS API:
* :c:func:`PyThread_create_key`: use :c:func:`PyThread_tss_alloc`.
* :c:func:`PyThread_delete_key`: use :c:func:`PyThread_tss_free`.
* :c:func:`PyThread_set_key_value`: use :c:func:`PyThread_tss_set`.
* :c:func:`PyThread_get_key_value`: use :c:func:`PyThread_tss_get`.
* :c:func:`PyThread_delete_key_value`: use :c:func:`PyThread_tss_delete`.
* :c:func:`PyThread_ReInitTLS`: no longer needed.
* Remove undocumented ``PY_TIMEOUT_MAX`` constant from the limited C API.
(Contributed by Victor Stinner in :gh:`110014`.)
Regression Test Changes
=======================
* Python built with :file:`configure` :option:`--with-pydebug` now
supports a :option:`-X presite=package.module <-X>` command-line
option. If used, it specifies a module that should be imported early
in the lifecycle of the interpreter, before ``site.py`` is executed.
(Contributed by Łukasz Langa in :gh:`110769`.)
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