What's New In Python 3.13
****************************
-:Editor: Thomas Wouters
+:Editors: Adam Turner and Thomas Wouters
.. Rules for maintenance:
:pep:`719` -- Python 3.13 Release Schedule
-.. 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
=============================
* The :mod:`copy` module now has a :func:`copy.replace` function,
with support for many builtin types and any class defining
the :func:`~object.__replace__` method.
-* The :mod:`dbm.sqlite3` module is now the default :mod:`dbm` backend.
+* The new :mod:`dbm.sqlite3` module is now the default :mod:`dbm` backend.
* The :mod:`os` module has a :ref:`suite of new functions <os-timerfd>`
for working with Linux's timer notification file descriptors.
* The :mod:`random` module now has a :ref:`command-line interface <random-cli>`.
* :pep:`696`: Type parameters (:data:`typing.TypeVar`, :data:`typing.ParamSpec`,
and :data:`typing.TypeVarTuple`) now support defaults.
* :pep:`702`: The new :func:`warnings.deprecated` decorator adds support
- for marking deprecations in the type system.
+ for marking deprecations in the type system and at runtime.
* :pep:`705`: :data:`typing.ReadOnly` can be used to mark an item of a
:class:`typing.TypedDict` as read-only for type checkers.
* :pep:`742`: :data:`typing.TypeIs` provides more intuitive
* :pep:`730`: Apple's iOS is now an :ref:`officially supported platform
<whatsnew313-platform-support>`, at :pep:`tier 3 <11#tier-3>`.
- Official Android support (:pep:`738`) is in the works as well.
+ Official Android support (:pep:`738`) is also in the works.
* ``wasm32-wasi`` is now supported as a :pep:`tier 2 <11#tier-2>` platform.
* ``wasm32-emscripten`` is no longer an officially supported platform.
Important removals:
* :ref:`PEP 594 <whatsnew313-pep594>`: The remaining 19 "dead batteries"
- have been removed from the standard library:
+ (legacy stdlib modules) 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`,
* Remove the :program:`2to3` tool and :mod:`!lib2to3` module
(deprecated in Python 3.11).
* Remove the :mod:`!tkinter.tix` module (deprecated in Python 3.6).
-* Remove :func:`!locale.resetlocale`.
-* Remove :mod:`!typing.io` and :mod:`!typing.re`.
+* Remove the :func:`!locale.resetlocale` function.
+* Remove the :mod:`!typing.io` and :mod:`!typing.re` namespaces.
* Remove chained :class:`classmethod` descriptors.
Release schedule changes:
expect some bugs and a substantial single-threaded performance hit.
Free-threaded builds of CPython support optionally running with the GIL
enabled at runtime using the environment variable :envvar:`PYTHON_GIL` or
-the command-line option :option:`-X gil`.
+the command-line option :option:`-X gil=1`.
To check if the current interpreter supports free-threading, :option:`python -VV <-V>`
and :attr:`sys.version` contain "experimental free-threading build".
Historically, the expected result of mutating the return value of
:func:`locals` has been left to individual Python implementations to define.
Starting from Python 3.13, :pep:`667` standardises
-the historical behaviour of CPython for most code execution scopes,
+the historical behavior of CPython for most code execution scopes,
but changes :term:`optimized scopes <optimized scope>`
(functions, generators, coroutines, comprehensions, and generator expressions)
to explicitly return independent snapshots of the currently assigned local
variables, including locally referenced nonlocal variables captured in closures.
This change to the semantics of :func:`locals` in optimized scopes also
-affects the default behaviour of code execution functions that implicitly
+affects the default behavior of code execution functions that implicitly
target :func:`!locals` if no explicit namespace is provided
(such as :func:`exec` and :func:`eval`).
In previous versions, whether or not changes could be accessed by calling
the value of the *optimize* argument.
(Contributed by Irit Katriel in :gh:`108113`).
+* Add a :attr:`~property.__name__` attribute on :class:`property` objects.
+ (Contributed by Eugene Toder in :gh:`101860`.)
+
* Add :exc:`PythonFinalizationError`, a new exception derived from
:exc:`RuntimeError` and used to signal when operations are blocked
during :term:`finalization <interpreter shutdown>`.
the :mod:`bz2`, :mod:`lzma`, :mod:`tarfile`, and :mod:`zipfile` modules.
(Contributed by Serhiy Storchaka in :gh:`115961`.)
-* Add a :attr:`~property.__name__` attribute on :class:`property` objects.
- (Contributed by Eugene Toder in :gh:`101860`.)
-
New Modules
===========
* The constructors of node types in the :mod:`ast` module are now
stricter in the arguments they accept,
- with more intuitive behaviour when arguments are omitted.
+ with more intuitive behavior when arguments are omitted.
If an optional field on an AST node is not included as an argument when
constructing an instance, the field will now be set to ``None``. Similarly,
return ``('', '')`` pairs in more situations where invalid email addresses
are encountered instead of potentially inaccurate values.
The two functions have a new optional *strict* parameter (default ``True``).
- To get the old behaviour (accepting malformed input), use ``strict=False``.
+ To get the old behavior (accepting malformed input), use ``strict=False``.
``getattr(email.utils, 'supports_strict_parsing', False)`` can be used
to check if the *strict* parameter is available.
(Contributed by Thomas Dwyer and Victor Stinner for :gh:`102988` to improve
(Contributed by Victor Stinner and Petr Viktorin in :gh:`110850`.)
* Add the :c:func:`PyDict_ContainsString` function
- with the same behaviour as :c:func:`PyDict_Contains`,
+ with the same behavior 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`.)
* Calling :func:`locals` in an :term:`optimized scope` now produces an
independent snapshot on each call, and hence no longer implicitly updates
- previously returned references. Obtaining the legacy CPython behaviour now
+ previously returned references. Obtaining the legacy CPython behavior now
requires explicit calls to update the initially returned dictionary with the
results of subsequent calls to :func:`!locals`. Code execution functions that
implicitly target :func:`!locals` (such as ``exec`` and ``eval``) must be
projects / thirdparty / Python / cpython.git / commitdiff
