Doc/whatsnew/3.13.rst
What's New In Python 3.13
:Editors: Adam Turner and Thomas Wouters
.. 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.
Python 3.13 was released on October 7, 2024.
For full details, see the :ref:changelog <changelog>.
.. seealso::
:pep:719 -- Python 3.13 Release Schedule
.. This section singles out the most important changes in Python 3.13. Brevity is key.
Python 3.13 is a stable release of the Python programming
language, with a mix of changes to the language, the implementation
and the standard library.
The biggest changes include a new interactive interpreter <whatsnew313-better-interactive-interpreter_>,
experimental support for running in a free-threaded mode <whatsnew313-free-threaded-cpython_> (:pep:703),
and a Just-In-Time compiler <whatsnew313-jit-compiler_>_ (:pep:744).
Error messages continue to improve, with tracebacks now highlighted in color
by default. The :func:locals builtin now has :ref:defined semantics <whatsnew313-locals-semantics> for changing the returned mapping,
and type parameters now support default values.
The library changes contain removal of deprecated APIs and modules,
as well as the usual improvements in user-friendliness and correctness.
Several legacy standard library modules have now been removed <whatsnew313-pep594_>_ following their deprecation in Python 3.11 (:pep:594).
This article doesn't attempt to provide a complete specification
of all new features, but instead gives a convenient overview.
For full details refer to the documentation,
such as the :ref:Library Reference <library-index>
and :ref:Language Reference <reference-index>.
To understand the complete implementation and design rationale for a change,
refer to the PEP for a particular new feature;
but note that PEPs usually are not kept up-to-date
once a feature has been fully implemented.
See Porting to Python 3.13_ for guidance on upgrading from
earlier versions of Python.
.. PEP-sized items next.
Interpreter improvements:
interactive interpreter <whatsnew313-better-interactive-interpreter> and
:ref:improved error messages <whatsnew313-improved-error-messages>.667: The :func:locals builtin now has
:ref:defined semantics <whatsnew313-locals-semantics> when mutating the
returned mapping. Python debuggers and similar tools may now more reliably
update local variables in optimized scopes even during concurrent code
execution.703: CPython 3.13 has experimental support for running with the
:term:global interpreter lock disabled. See :ref:Free-threaded CPython <whatsnew313-free-threaded-cpython> for more details.744: A basic :ref:JIT compiler <whatsnew313-jit-compiler> was added.
It is currently disabled by default (though we may turn it on later).
Performance improvements are modest -- we expect to improve this
over the next few releases.interactive interpreter <whatsnew313-better-interactive-interpreter>,
as well as in :ref:tracebacks <whatsnew313-improved-error-messages>
and :ref:doctest <whatsnew313-doctest> output.
This can be disabled through the :envvar:PYTHON_COLORS and |NO_COLOR|_
environment variables.Python data model improvements:
~type.__static_attributes__ stores the names of attributes accessed
through self.X in any function in a class body.~type.__firstlineno__ records the first line number of a class
definition.Significant improvements in the standard library:
PythonFinalizationError exception, raised when an operation
is blocked during :term:finalization <interpreter shutdown>.argparse module now supports deprecating command-line options,
positional arguments, and subcommands.base64.z85encode and :func:base64.z85decode
support encoding and decoding Z85 data_.copy module now has a :func:copy.replace function,
with support for many builtin types and any class defining
the :func:~object.__replace__ method.dbm.sqlite3 module is now the default :mod:dbm backend.os module has a :ref:suite of new functions <os-timerfd>
for working with Linux's timer notification file descriptors.random module now has a :ref:command-line interface <random-cli>.Security improvements:
ssl.create_default_context sets :data:ssl.VERIFY_X509_PARTIAL_CHAIN
and :data:ssl.VERIFY_X509_STRICT as default flags.C API improvements:
Py_mod_gil slot is now used to indicate that
an extension module supports running with the :term:GIL disabled.PyTime C API </c-api/time> has been added,
providing access to system clocks.PyMutex is a new lightweight mutex that occupies a single byte.suite of functions <c-api-monitoring>
for generating :pep:669 monitoring events in the C API.New typing features:
696: Type parameters (:data:typing.TypeVar, :data:typing.ParamSpec,
and :data:typing.TypeVarTuple) now support defaults.702: The new :func:warnings.deprecated decorator adds support
for marking deprecations in the type system and at runtime.705: :data:typing.ReadOnly can be used to mark an item of a
:class:typing.TypedDict as read-only for type checkers.742: :data:typing.TypeIs provides more intuitive
type narrowing behavior, as an alternative to :data:typing.TypeGuard.Platform support:
730: Apple's iOS is now an :ref:officially supported platform <whatsnew313-platform-support>, at :pep:tier 3 <11#tier-3>.738: Android is now an :ref:officially supported platform <whatsnew313-platform-support>, at :pep:tier 3 <11#tier-3>.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:
PEP 594 <whatsnew313-pep594>: The remaining 19 "dead batteries"
(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,
:mod:!spwd, :mod:!sunau, :mod:!telnetlib, :mod:!uu and :mod:!xdrlib.2to3 tool and :mod:!lib2to3 module
(deprecated in Python 3.11).!tkinter.tix module (deprecated in Python 3.6).!locale.resetlocale function.!typing.io and :mod:!typing.re namespaces.classmethod descriptors.Release schedule changes:
:pep:602 ("Annual Release Cycle for Python") has been updated
to extend the full support ('bugfix') period for new releases to two years.
This updated policy means that:
.. _whatsnew313-better-interactive-interpreter:
Python now uses a new :term:interactive shell by default, based on code
from the PyPy project_.
When the user starts the :term:REPL from an interactive terminal,
the following new features are now supported:
help, :kbd:exit,
and :kbd:quit, without the need to call them as functions.color enabled by default <using-on-controlling-color>.F1 with a separate command
history.F2 that skips output as well as the
:term:>>> and :term:... prompts.F3 that makes pasting larger blocks of code
easier (press :kbd:F3 again to return to the regular prompt).To disable the new interactive shell,
set the :envvar:PYTHON_BASIC_REPL environment variable.
For more on interactive mode, see :ref:tut-interac.
(Contributed by Pablo Galindo Salgado, Łukasz Langa, and
Lysandros Nikolaou in :gh:111201 based on code from the PyPy project.
Windows support contributed by Dino Viehland and Anthony Shaw.)
.. _PyPy project: https://pypy.org/
.. _whatsnew313-improved-error-messages:
The interpreter now uses color by default when displaying tracebacks in the
terminal. This feature :ref:can be controlled <using-on-controlling-color>
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.)
A common mistake is to write a script with the same name as a standard library module. When this results in errors, we now display a more helpful error message:
.. code-block:: pytb
$ python random.py Traceback (most recent call last): File "/home/me/random.py", line 1, in <module> import random File "/home/me/random.py", line 3, in <module> print(random.randint(5)) ^^^^^^^^^^^^^^ AttributeError: module 'random' has no attribute 'randint' (consider renaming '/home/me/random.py' since it has the same name as the standard library module named 'random' and prevents importing that standard library module)
Similarly, if a script has the same name as a third-party module that it attempts to import and this results in errors, we also display a more helpful error message:
.. code-block:: pytb
$ python numpy.py Traceback (most recent call last): File "/home/me/numpy.py", line 1, in <module> import numpy as np File "/home/me/numpy.py", line 3, in <module> np.array([1, 2, 3]) ^^^^^^^^ AttributeError: module 'numpy' has no attribute 'array' (consider renaming '/home/me/numpy.py' if it has the same name as a library you intended to import)
(Contributed by Shantanu Jain in :gh:95754.)
The error message now tries to suggest the correct keyword argument when an incorrect keyword argument is passed to a function.
.. code-block:: pycon
"Better error messages!".split(max_split=1) Traceback (most recent call last): File "<python-input-0>", line 1, in <module> "Better error messages!".split(max_split=1) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^ TypeError: split() got an unexpected keyword argument 'max_split'. Did you mean 'maxsplit'?
(Contributed by Pablo Galindo Salgado and Shantanu Jain in :gh:107944.)
.. _whatsnew313-free-threaded-cpython:
CPython now has experimental support for running in a free-threaded mode,
with the :term:global interpreter lock (GIL) disabled.
This is an experimental feature and therefore is not enabled by default.
The free-threaded mode requires a different executable,
usually called python3.13t or python3.13t.exe.
Pre-built binaries marked as free-threaded can be installed as part of
the official :ref:Windows <install-freethreaded-windows>
and :ref:macOS <install-freethreaded-macos> installers,
or CPython can be built from source with the :option:--disable-gil option.
Free-threaded execution allows for full utilization of the available
processing power by running threads in parallel on available CPU cores.
While not all software will benefit from this automatically, programs
designed with threading in mind will run faster on multi-core hardware.
The free-threaded mode is experimental and work is ongoing to improve it:
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=1.
To check if the current interpreter supports free-threading, :option:python -VV <-V>
and :data:sys.version contain "experimental free-threading build".
The new :func:!sys._is_gil_enabled function can be used to check whether
the GIL is actually disabled in the running process.
C-API extension modules need to be built specifically for the free-threaded
build. Extensions that support running with the :term:GIL disabled should
use the :c:data:Py_mod_gil slot. Extensions using single-phase init should
use :c:func:PyUnstable_Module_SetGIL to indicate whether they support
running with the GIL disabled. Importing C extensions that don't use these
mechanisms will cause the GIL to be enabled, unless the GIL was explicitly
disabled with the :envvar:PYTHON_GIL environment variable or the
:option:-X gil=0 option.
pip 24.1 or newer is required to install packages with C extensions in the
free-threaded build.
This work was made possible thanks to many individuals and organizations, including the large community of contributors to Python and third-party projects to test and enable free-threading support. Notable contributors include: Sam Gross, Ken Jin, Donghee Na, Itamar Oren, Matt Page, Brett Simmers, Dino Viehland, Carl Meyer, Nathan Goldbaum, Ralf Gommers, Lysandros Nikolaou, and many others. Many of these contributors are employed by Meta, which has provided significant engineering resources to support this project.
.. seealso::
:pep:703 "Making the Global Interpreter Lock Optional in CPython"
contains rationale and information surrounding this work.
Porting Extension Modules to Support Free-Threading <https://py-free-threading.github.io/porting/>_: A community-maintained
porting guide for extension authors.
.. _whatsnew313-jit-compiler:
When CPython is configured and built using
the :option:!--enable-experimental-jit option,
a just-in-time (JIT) compiler is added which may speed up some Python programs.
On Windows, use PCbuild/build.bat --experimental-jit to enable the JIT
or --experimental-jit-interpreter to enable the Tier 2 interpreter.
Build requirements and further supporting information are contained at__
:file:Tools/jit/README.md.
__ https://github.com/python/cpython/blob/main/Tools/jit/README.md
The :option:!--enable-experimental-jit option takes these (optional) values,
defaulting to yes if :option:!--enable-experimental-jit is present
without the optional value.
no: Disable the entire Tier 2 and JIT pipeline.yes: Enable the JIT.
To disable the JIT at runtime, pass the environment variable PYTHON_JIT=0.yes-off: Build the JIT but disable it by default.
To enable the JIT at runtime, pass the environment variable PYTHON_JIT=1.interpreter: Enable the Tier 2 interpreter but disable the JIT.
The interpreter can be disabled by running with PYTHON_JIT=0.The internal architecture is roughly as follows:
What's new in 3.11 <whatsnew311-pep659> for details.--enable-experimental-jit=interpreter... seealso:: :pep:744
(JIT by Brandt Bucher, inspired by a paper by Haoran Xu and Fredrik Kjolstad. Tier 2 IR by Mark Shannon and Guido van Rossum. Tier 2 optimizer by Ken Jin.)
.. _whatsnew313-locals-semantics:
localsHistorically, 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 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 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
:func:!locals after calling the code execution function was
implementation-dependent. In CPython specifically, such code would typically
appear to work as desired, but could sometimes fail in optimized scopes based
on other code (including debuggers and code execution tracing tools)
potentially resetting the shared snapshot in that scope.
Now, the code will always run against an independent snapshot of
the local variables in optimized scopes, and hence the changes will never
be visible in subsequent calls to :func:!locals.
To access the changes made in these cases, an explicit namespace reference
must now be passed to the relevant function.
Alternatively, it may make sense to update affected code to use a higher level
code execution API that returns the resulting code execution namespace
(e.g. :func:runpy.run_path when executing Python files from disk).
To ensure debuggers and similar tools can reliably update local variables in
scopes affected by this change, :attr:FrameType.f_locals <frame.f_locals> now
returns a write-through proxy to the frame's local and locally referenced
nonlocal variables in these scopes, rather than returning an inconsistently
updated shared dict instance with undefined runtime semantics.
See :pep:667 for more details, including related C API changes
and deprecations. Porting notes are also provided below for the affected
:ref:Python APIs <pep667-porting-notes-py> and :ref:C APIs <pep667-porting-notes-c>.
(PEP and implementation contributed by Mark Shannon and Tian Gao in
:gh:74929. Documentation updates provided by Guido van Rossum and
Alyssa Coghlan.)
.. _whatsnew313-platform-support:
:pep:730: iOS is now a :pep:11 supported platform, with the
arm64-apple-ios and arm64-apple-ios-simulator targets at tier 3
(iPhone and iPad devices released after 2013 and the Xcode iOS simulator
running on Apple silicon hardware, respectively).
x86_64-apple-ios-simulator
(the Xcode iOS simulator running on older x86_64 hardware)
is not a tier 3 supported platform, but will have best-effort support.
(PEP written and implementation contributed by Russell Keith-Magee in
:gh:114099.)
:pep:738: Android is now a :pep:11 supported platform, with the
aarch64-linux-android and x86_64-linux-android targets at tier 3.
The 32-bit targets arm-linux-androideabi and i686-linux-android
are not tier 3 supported platforms, but will have best-effort support.
(PEP written and implementation contributed by Malcolm Smith in
:gh:116622.)
.. seealso:: :pep:730, :pep:738
The compiler now strips common leading whitespace
from every line in a docstring.
This reduces the size of the :term:bytecode cache <bytecode>
(such as .pyc files), with reductions in file size of around 5%,
for example in :mod:!sqlalchemy.orm.session from SQLAlchemy 2.0.
This change affects tools that use docstrings, such as :mod:doctest.
.. doctest::
def spam(): ... """ ... This is a docstring with ... leading whitespace. ... ... It even has multiple paragraphs! ... """ ... spam.doc '\nThis is a docstring with\n leading whitespace.\n\nIt even has multiple paragraphs!\n'
(Contributed by Inada Naoki in :gh:81283.)
:ref:Annotation scopes <annotation-scopes> within class scopes
can now contain lambdas and comprehensions.
Comprehensions that are located within class scopes
are not inlined into their parent scope.
.. code-block:: python
class C[T]: type Alias = lambda: T
(Contributed by Jelle Zijlstra in :gh:109118 and :gh:118160.)
:ref:Future statements <future> are no longer triggered by
relative imports of the :mod:__future__ module,
meaning that statements of the form from .__future__ import ...
are now simply standard relative imports, with no special features activated.
(Contributed by Jeremiah Gabriel Pascual in :gh:118216.)
:keyword:global declarations are now permitted in :keyword:except blocks
when that global is used in the :keyword:else block.
Previously this raised an erroneous :exc:SyntaxError.
(Contributed by Irit Katriel in :gh:111123.)
Add :envvar:PYTHON_FROZEN_MODULES, a new environment variable that
determines whether frozen modules are ignored by the import machinery,
equivalent to the :option:-X frozen_modules <-X> command-line option.
(Contributed by Yilei Yang in :gh:111374.)
Add :ref:support for the perf profiler <perf_profiling> working
without frame pointers <https://en.wikipedia.org/wiki/Call_stack>_ through
the new environment variable :envvar:PYTHON_PERF_JIT_SUPPORT
and command-line option :option:-X perf_jit <-X>.
(Contributed by Pablo Galindo in :gh:118518.)
The location of a :file:.python_history file can be changed via the
new :envvar:PYTHON_HISTORY environment variable.
(Contributed by Levi Sabah, Zackery Spytz and Hugo van Kemenade
in :gh:73965.)
Classes have a new :attr:~type.__static_attributes__ attribute.
This is populated by the compiler with a tuple of the class's attribute names
which are assigned through self.<name> from any function in its body.
(Contributed by Irit Katriel in :gh:115775.)
The compiler now creates a :attr:!__firstlineno__ attribute on classes
with the line number of the first line of the class definition.
(Contributed by Serhiy Storchaka in :gh:118465.)
The :func:exec and :func:eval builtins now accept
the globals and locals arguments as keywords.
(Contributed by Raphael Gaschignard in :gh:105879)
The :func:compile builtin now accepts 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).
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 following callables now raise :exc:!PythonFinalizationError,
instead of :exc:RuntimeError:
_thread.start_new_threados.forkos.forkptysubprocess.Popen(Contributed by Victor Stinner in :gh:114570.)
Allow the count argument of :meth:str.replace to be a keyword.
(Contributed by Hugo van Kemenade in :gh:106487.)
Many functions now emit a warning if a boolean value is passed as
a file descriptor argument.
This can help catch some errors earlier.
(Contributed by Serhiy Storchaka in :gh:82626.)
Added :attr:!name and :attr:!mode attributes
for compressed and archived file-like objects in
the :mod:bz2, :mod:lzma, :mod:tarfile, and :mod:zipfile modules.
(Contributed by Serhiy Storchaka in :gh:115961.)
dbm.sqlite3: An SQLite backend for :mod:dbm.
(Contributed by Raymond Hettinger and Erlend E. Aasland in :gh:100414.)~argparse.ArgumentParser.add_argument
and :meth:!add_parser methods, to enable deprecating
command-line options, positional arguments, and subcommands.
(Contributed by Serhiy Storchaka in :gh:83648.)Add the 'w' type code (Py_UCS4) for Unicode characters.
It should be used instead of the deprecated 'u' type code.
(Contributed by Inada Naoki in :gh:80480.)
Register :class:array.array as a :class:~collections.abc.MutableSequence
by implementing the :meth:~array.array.clear method.
(Contributed by Mike Zimin in :gh:114894.)
The constructors of node types in the :mod:ast module are now
stricter in the arguments they accept,
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,
if a list field is omitted, that field will now be set to an empty list,
and if an :class:!expr_context field is omitted, it defaults to
:class:Load() <ast.Load>.
(Previously, in all cases, the attribute would be missing on the newly
constructed AST node instance.)
In all other cases, where a required argument is omitted,
the node constructor will emit a :exc:DeprecationWarning.
This will raise an exception in Python 3.15.
Similarly, passing a keyword argument to the constructor
that does not map to a field on the AST node is now deprecated,
and will raise an exception in Python 3.15.
These changes do not apply to user-defined subclasses of :class:ast.AST
unless the class opts in to the new behavior
by defining the :attr:.AST._field_types mapping.
(Contributed by Jelle Zijlstra in :gh:105858, :gh:117486, and :gh:118851.)
:func:ast.parse now accepts an optional argument optimize
which is passed on to :func:compile.
This makes it possible to obtain an optimized AST.
(Contributed by Irit Katriel in :gh:108113.)
:func:asyncio.as_completed now returns an object that is both an
:term:asynchronous iterator and a plain :term:iterator
of :term:awaitables <awaitable>.
The awaitables yielded by asynchronous iteration include original task
or future objects that were passed in,
making it easier to associate results with the tasks being completed.
(Contributed by Justin Arthur in :gh:77714.)
: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.)
:meth:.DatagramTransport.sendto will now send zero-length
datagrams if called with an empty bytes object.
The transport flow control also now accounts for the datagram header
when calculating the buffer size.
(Contributed by Jamie Phan in :gh:115199.)
Add :meth:Queue.shutdown <asyncio.Queue.shutdown>
and :exc:~asyncio.QueueShutDown to manage queue termination.
(Contributed by Laurie Opperman and Yves Duprat in :gh:104228.)
Add the :meth:.Server.close_clients and :meth:.Server.abort_clients
methods, which more forcefully close an asyncio server.
(Contributed by Pierre Ossman in :gh:113538.)
Accept a tuple of separators in :meth:.StreamReader.readuntil,
stopping when any one of them is encountered.
(Contributed by Bruce Merry in :gh:81322.)
Improve the behavior of :class:~asyncio.TaskGroup when
an external cancellation collides with an internal cancellation.
For example, when two task groups are nested
and both experience an exception in a child task simultaneously,
it was possible that the outer task group would hang,
because its internal cancellation was swallowed by the inner task group.
In the case where a task group is cancelled externally
and also must raise an :exc:ExceptionGroup,
it will now call the parent task's :meth:~asyncio.Task.cancel method.
This ensures that a :exc:~asyncio.CancelledError will be raised
at the next :keyword:await, so the cancellation is not lost.
An added benefit of these changes is that task groups now preserve
the cancellation count (:meth:~asyncio.Task.cancelling).
In order to handle some corner cases, :meth:~asyncio.Task.uncancel may now
reset the undocumented _must_cancel flag
when the cancellation count reaches zero.
(Inspired by an issue reported by Arthur Tacca in :gh:116720.)
When :meth:.TaskGroup.create_task is called on an inactive
:class:~asyncio.TaskGroup, the given coroutine will be closed (which
prevents a :exc:RuntimeWarning about the given coroutine being
never awaited).
(Contributed by Arthur Tacca and Jason Zhang in :gh:115957.)
The function and methods named create_task have received a new
**kwargs argument that is passed through to the task constructor.
This change was accidentally added in 3.13.3,
and broke the API contract for custom task factories.
Several third-party task factories implemented workarounds for this.
In 3.13.4 and later releases the old factory contract is honored
once again (until 3.14).
To keep the workarounds working, the extra **kwargs argument still
allows passing additional keyword arguments to :class:~asyncio.Task
and to custom task factories.
This affects the following function and methods:
:meth:asyncio.create_task,
:meth:asyncio.loop.create_task,
:meth:asyncio.TaskGroup.create_task.
(Contributed by Thomas Grainger in :gh:128307.)
Add :func:~base64.z85encode and :func:~base64.z85decode functions
for encoding :class:bytes as Z85 data_
and decoding Z85-encoded data to :class:!bytes.
(Contributed by Matan Perelman in :gh:75299.)
.. _Z85 data: https://rfc.zeromq.org/spec/32/
os.process_cpu_count instead of :func:os.cpu_count.
(Contributed by Victor Stinner in :gh:109649.)os.process_cpu_count instead of :func:os.cpu_count.
(Contributed by Victor Stinner in :gh:109649.)~configparser.ConfigParser now has support for unnamed sections,
which allows for top-level key-value pairs.
This can be enabled with the new allow_unnamed_section parameter.
(Contributed by Pedro Sousa Lacerda in :gh:66449.)The new :func:~copy.replace function and the :meth:replace protocol <object.__replace__> make creating modified copies of objects much simpler.
This is especially useful when working with immutable objects.
The following types support the :func:~copy.replace function
and implement the replace protocol:
collections.namedtupledataclasses.dataclassdatetime.datetime, :class:datetime.date, :class:datetime.timeinspect.Signature, :class:inspect.Parametertypes.SimpleNamespacecode objects <code-objects>Any user-defined class can also support :func:copy.replace by defining
the :meth:~object.__replace__ method.
(Contributed by Serhiy Storchaka in :gh:108751.)
As a consequence of necessary internal refactoring, initialization of
internal metaclasses now happens in __init__ rather
than in __new__. This affects projects that subclass these internal
metaclasses to provide custom initialization.
Generally:
__new__ after calling super().__new__
should be moved to __init__.__new__ method.See :gh:124520 for discussion and links to changes in some affected
projects.
:class:ctypes.Structure objects have a new :attr:~ctypes.Structure._align_
attribute which allows the alignment of the structure being packed to/from
memory to be specified explicitly.
(Contributed by Matt Sanderson in :gh:112433)
Add :mod:dbm.sqlite3, a new module which implements an SQLite backend,
and make it the default :mod:!dbm backend.
(Contributed by Raymond Hettinger and Erlend E. Aasland in :gh:100414.)
Allow removing all items from the database through
the new :meth:!clear methods of the GDBM and NDBM database objects.
(Contributed by Donghee Na in :gh:107122.)
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
:option:-O <dis --show-offsets> command-line option
or the show_offsets argument.
(Contributed by Irit Katriel in :gh:112137.)
:meth:~dis.get_instructions no longer represents cache entries
as separate instructions.
Instead, it returns them as part of the :class:~dis.Instruction,
in the new cache_info field.
The show_caches argument to :meth:~dis.get_instructions is deprecated
and no longer has any effect.
(Contributed by Irit Katriel in :gh:112962.)
.. _whatsnew313-doctest:
:mod:doctest output is now colored by default.
This can be controlled via the new :envvar:PYTHON_COLORS environment
variable as well as the canonical |NO_COLOR|_
and |FORCE_COLOR|_ environment variables.
See also :ref:using-on-controlling-color.
(Contributed by Hugo van Kemenade in :gh:117225.)
The :meth:.DocTestRunner.run method now counts the number of skipped tests.
Add the :attr:.DocTestRunner.skips and :attr:.TestResults.skipped attributes.
(Contributed by Victor Stinner in :gh:108794.)
Headers with embedded newlines are now quoted on output.
The :mod:~email.generator will now refuse to serialize (write) headers
that are improperly folded or delimited, such that they would be parsed as
multiple headers or joined with adjacent data.
If you need to turn this safety feature off,
set :attr:~email.policy.Policy.verify_generated_headers.
(Contributed by Bas Bloemsaat and Petr Viktorin in :gh:121650.)
:func:~email.utils.getaddresses and :func:~email.utils.parseaddr now
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 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
the :cve:2023-27043 fix.)
~enum.EnumDict has been made public to better support subclassing
:class:~enum.EnumType.~fractions.Fraction objects now support the standard
:ref:format specification mini-language <formatspec> rules
for fill, alignment, sign handling, minimum width, and grouping.
(Contributed by Mark Dickinson in :gh:111320.)~glob.translate, a function to convert a path specification
with shell-style wildcards to a regular expression.
(Contributed by Barney Gale in :gh:72904.)The following functions in :mod:importlib.resources now allow accessing
a directory (or tree) of resources, using multiple positional arguments
(the encoding and errors arguments in the text-reading functions
are now keyword-only):
~importlib.resources.is_resource~importlib.resources.open_binary~importlib.resources.open_text~importlib.resources.path~importlib.resources.read_binary~importlib.resources.read_textThese functions are no longer deprecated and are not scheduled for removal.
(Contributed by Petr Viktorin in :gh:116608.)
:func:~importlib.resources.contents remains deprecated in favor of
the fully-featured :class:~importlib.resources.abc.Traversable API.
However, there is now no plan to remove it.
(Contributed by Petr Viktorin in :gh:116608.)
~io.IOBase finalizer now logs any errors raised by
the :meth:~io.IOBase.close method with :data:sys.unraisablehook.
Previously, errors were ignored silently by default,
and only logged in :ref:Python Development Mode <devmode>
or when using a :ref:Python debug build <debug-build>.
(Contributed by Victor Stinner in :gh:62948.)Add the :attr:.IPv4Address.ipv6_mapped property,
which returns the IPv4-mapped IPv6 address.
(Contributed by Charles Machalow in :gh:109466.)
Fix is_global and is_private behavior in
:class:~ipaddress.IPv4Address, :class:~ipaddress.IPv6Address,
:class:~ipaddress.IPv4Network, and :class:~ipaddress.IPv6Network.
(Contributed by Jakub Stasiak in :gh:113171.)
~itertools.batched has a new strict parameter,
which raises a :exc:ValueError if the final batch is shorter
than the specified batch size.
(Contributed by Raymond Hettinger in :gh:113202.)allow_code=False prevents serialization and de-serialization
of code objects which are incompatible between Python versions.
(Contributed by Serhiy Storchaka in :gh:113626.)~math.fma performs fused multiply-add operations.
This computes x * y + z with only a single round,
and so avoids any intermediate loss of precision.
It wraps the fma() function provided by C99,
and follows the specification of the IEEE 754 "fusedMultiplyAdd" operation
for special cases.
(Contributed by Mark Dickinson and Victor Stinner in :gh:73468.)~mimetypes.guess_file_type function to guess a MIME type
from a filesystem path.
Using paths with :func:~mimetypes.guess_type is now :term:soft deprecated.
(Contributed by Serhiy Storchaka in :gh:66543.):class:~mmap.mmap is now protected from crashing on Windows when the
mapped memory is inaccessible due to file system errors or access violations.
(Contributed by Jannis Weigend in :gh:118209.)
:class:~mmap.mmap has a new :meth:~mmap.mmap.seekable method
that can be used when a seekable file-like object is required.
The :meth:~mmap.mmap.seek method now returns the new absolute position.
(Contributed by Donghee Na and Sylvie Liberman in :gh:111835.)
The new UNIX-only trackfd parameter for :class:~mmap.mmap controls
file descriptor duplication;
if false, the file descriptor specified by fileno will not be duplicated.
(Contributed by Zackery Spytz and Petr Viktorin in :gh:78502.)
os.process_cpu_count instead of :func:os.cpu_count.
(Contributed by Victor Stinner in :gh:109649.)Add :func:~os.process_cpu_count function to get the number
of logical CPU cores usable by the calling thread of the current process.
(Contributed by Victor Stinner in :gh:109649.)
: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 application code
or the container itself.
(Contributed by Donghee Na in :gh:109595.)
Add a :ref:low level interface <os-timerfd> to Linux's
:manpage:timer file descriptors <timerfd_create(2)>
via :func:~os.timerfd_create,
:func:~os.timerfd_settime, :func:~os.timerfd_settime_ns,
:func:~os.timerfd_gettime, :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.lchmod and the follow_symlinks argument of :func:~os.chmod
are both now available on Windows.
Note that the default value of follow_symlinks
in :func:!lchmod is False on Windows.
(Contributed by Serhiy Storchaka in :gh:59616.)
:func:~os.fchmod and support for file descriptors in :func:~os.chmod
are both now available on Windows.
(Contributed by Serhiy Storchaka in :gh:113191.)
On Windows, :func:~os.mkdir and :func:~os.makedirs now support passing
a mode value of 0o700 to apply access control to the new directory.
This implicitly affects :func:tempfile.mkdtemp
and is a mitigation for :cve:2024-4030.
Other values for mode continue to be ignored.
(Contributed by Steve Dower in :gh:118486.)
:func:~os.posix_spawn now accepts None for the env argument,
which makes the newly spawned process use the current process environment.
(Contributed by Jakub Kulik in :gh:113119.)
:func:~os.posix_spawn can now use the :const:~os.POSIX_SPAWN_CLOSEFROM
attribute in the file_actions parameter on platforms that support
:c:func:!posix_spawn_file_actions_addclosefrom_np.
(Contributed by Jakub Kulik in :gh:113117.)
Add :func:~os.path.isreserved to check if a path is reserved
on the current system.
This function is only available on Windows.
(Contributed by Barney Gale in :gh:88569.)
On Windows, :func:~os.path.isabs no longer considers paths
starting with exactly one slash (\ or /) to be absolute.
(Contributed by Barney Gale and Jon Foster in :gh:44626.)
: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.)
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 a new constructor for creating :class:~pathlib.Path objects
from 'file' URIs (file:///), :meth:.Path.from_uri.
(Contributed by Barney Gale in :gh:107465.)
Add :meth:.PurePath.full_match for matching paths with
shell-style wildcards, including the recursive wildcard "**".
(Contributed by Barney Gale in :gh:73435.)
Add the :attr:.PurePath.parser class attribute to store the
implementation of :mod:os.path used
for low-level path parsing and joining.
This will be either :mod:!posixpath or :mod:!ntpath.
Add recurse_symlinks keyword-only argument to
:meth:.Path.glob and :meth:~pathlib.Path.rglob.
(Contributed by Barney Gale in :gh:77609.)
:meth:.Path.glob and :meth:~pathlib.Path.rglob
now return files and directories when given a pattern that ends with "**".
Previously, only directories were returned.
(Contributed by Barney Gale in :gh:70303.)
Add the follow_symlinks keyword-only argument to
:meth:Path.is_file <pathlib.Path.is_file>,
:meth:Path.is_dir <pathlib.Path.is_dir>,
:meth:.Path.owner, and :meth:.Path.group.
(Contributed by Barney Gale in :gh:105793 and Kamil Turek in :gh:107962.)
:func:breakpoint and :func:~pdb.set_trace now enter the debugger immediately
rather than on the next line of code to be executed. This change prevents the
debugger from breaking outside of the context when :func:!breakpoint is positioned
at the end of the context.
(Contributed by Tian Gao in :gh:118579.)
sys.path[0] is no longer replaced by the directory of the script
being debugged when :attr:sys.flags.safe_path is set.
(Contributed by Tian Gao and Christian Walther in :gh:111762.)
:mod:zipapp is now supported as a debugging target.
(Contributed by Tian Gao in :gh:118501.)
Add ability to move between chained exceptions during
post-mortem debugging in :func:~pdb.pm using
the new :pdbcmd:exceptions [exc_number] <exceptions> command for Pdb.
(Contributed by Matthias Bussonnier in :gh:106676.)
Expressions and statements whose prefix is a pdb command are now correctly
identified and executed.
(Contributed by Tian Gao in :gh:108464.)
Queue.shutdown <queue.Queue.shutdown> and :exc:~queue.ShutDown
to manage queue termination.
(Contributed by Laurie Opperman and Yves Duprat in :gh:104750.)command-line interface <random-cli>.
(Contributed by Hugo van Kemenade in :gh:118131.)!re.error to :exc:~re.PatternError for improved clarity.
:exc:!re.error is kept for backward compatibility.~shutil.chown.
(Contributed by Berker Peksag and Tahia K in :gh:62308).pth files are now decoded using UTF-8 first,
and then with the :term:locale encoding if UTF-8 decoding fails.
(Contributed by Inada Naoki in :gh:117802.)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.)
Add the filter keyword-only parameter to :meth:.Connection.iterdump
for filtering database objects to dump.
(Contributed by Mariusz Felisiak in :gh:91602.)
The :func:~ssl.create_default_context API now includes
:data:~ssl.VERIFY_X509_PARTIAL_CHAIN and :data:~ssl.VERIFY_X509_STRICT
in its default flags.
.. note::
:data:~ssl.VERIFY_X509_STRICT may reject pre-:rfc:5280
or malformed certificates that the underlying OpenSSL implementation
might otherwise accept.
Whilst disabling this is not recommended, you can do so using:
.. code-block:: python
import ssl
ctx = ssl.create_default_context()
ctx.verify_flags &= ~ssl.VERIFY_X509_STRICT
(Contributed by William Woodruff in :gh:112389.)
Add :func:~statistics.kde for kernel density estimation.
This makes it possible to estimate a continuous probability density function
from a fixed number of discrete samples.
(Contributed by Raymond Hettinger in :gh:115863.)
Add :func:~statistics.kde_random for sampling from an
estimated probability density function created by :func:~statistics.kde.
(Contributed by Raymond Hettinger in :gh:115863.)
.. _whatsnew313-subprocess:
The :mod:subprocess module now uses the :func:~os.posix_spawn function in
more situations.
Notably, when close_fds is True (the default),
:func:~os.posix_spawn will be used when the C library provides
:c:func:!posix_spawn_file_actions_addclosefrom_np,
which includes recent versions of Linux, FreeBSD, and Solaris.
On Linux, this should perform similarly to the existing
Linux :c:func:!vfork based code.
A private control knob :attr:!subprocess._USE_POSIX_SPAWN can
be set to False if you need to force :mod:subprocess
to never use :func:~os.posix_spawn.
Please report your reason and platform details in
the :ref:issue tracker <using-the-tracker> if you set this
so that we can improve our API selection logic for everyone.
(Contributed by Jakub Kulik in :gh:113117.)
~sys._is_interned function to test if a string was interned.
This function is not guaranteed to exist in all implementations of Python.
(Contributed by Serhiy Storchaka in :gh:78573.)0o700 used by :func:tempfile.mkdtemp now
limits access to the new directory due to changes to :func:os.mkdir.
This is a mitigation for :cve:2024-4030.
(Contributed by Steve Dower in :gh:118486.)On Windows, :func:~time.monotonic now uses the
QueryPerformanceCounter() clock for a resolution of 1 microsecond,
instead of the GetTickCount64() clock which has
a resolution of 15.6 milliseconds.
(Contributed by Victor Stinner in :gh:88494.)
On Windows, :func:~time.time now uses the
GetSystemTimePreciseAsFileTime() clock for a resolution of 1 microsecond,
instead of the GetSystemTimeAsFileTime() clock which has
a resolution of 15.6 milliseconds.
(Contributed by Victor Stinner in :gh:63207.)
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.)
The :mod:tkinter widget method :meth:!wm_attributes now accepts
the attribute name without the minus prefix to get window attributes,
for example w.wm_attributes('alpha')
and allows specifying attributes and values to set as keyword arguments,
for example w.wm_attributes(alpha=0.5).
(Contributed by Serhiy Storchaka in :gh:43457.)
:meth:!wm_attributes can now return attributes as a :class:dict,
by using the new optional keyword-only parameter return_python_dict.
(Contributed by Serhiy Storchaka in :gh:43457.)
:meth:!Text.count can now return a simple :class:int
when the new optional keyword-only parameter return_ints is used.
Otherwise, the single count is returned as a 1-tuple or None.
(Contributed by Serhiy Storchaka in :gh:97928.)
Support 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.)
Add the :meth:!after_info method for Tkinter widgets.
(Contributed by Cheryl Sabella in :gh:77020.)
Add a new :meth:!copy_replace method to :class:!PhotoImage
to copy a region from one image to another,
possibly with pixel zooming, subsampling, or both.
(Contributed by Serhiy Storchaka in :gh:118225.)
Add from_coords parameter to the :class:!PhotoImage methods
:meth:!copy, :meth:!zoom and :meth:!subsample.
Add zoom and subsample parameters to the :class:!PhotoImage method
:meth:!copy.
(Contributed by Serhiy Storchaka in :gh:118225.)
Add the :class:!PhotoImage methods
:meth:!read to read an image from a file
and :meth:!data to get the image data.
Add background and grayscale parameters to the :meth:!write method.
(Contributed by Serhiy Storchaka in :gh:118271.)
Add the :attr:~traceback.TracebackException.exc_type_str attribute
to :class:~traceback.TracebackException,
which holds a string display of the exc_type.
Deprecate the :attr:~traceback.TracebackException.exc_type attribute,
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.)
Add a new show_group keyword-only parameter to
:meth:.TracebackException.format_exception_only to (recursively) format
the nested exceptions of a :exc:BaseExceptionGroup instance.
(Contributed by Irit Katriel in :gh:105292.)
~types.SimpleNamespace can now take a single positional argument
to initialise the namespace's arguments.
This argument must either be a mapping or an iterable of key-value pairs.
(Contributed by Serhiy Storchaka in :gh:108191.):pep:705: Add :data:~typing.ReadOnly, a special typing construct
to mark a :class:~typing.TypedDict item as read-only for type checkers.
:pep:742: Add :data:~typing.TypeIs, a typing construct
that can be used to instruct a type checker how to narrow a type.
Add :data:~typing.NoDefault, a sentinel object used to represent
the defaults of some parameters in the :mod:typing module.
(Contributed by Jelle Zijlstra in :gh:116126.)
Add :func:~typing.get_protocol_members to return the set of members
defining a :class:typing.Protocol.
(Contributed by Jelle Zijlstra in :gh:104873.)
Add :func:~typing.is_protocol to check whether a class
is a :class:~typing.Protocol.
(Contributed by Jelle Zijlstra in :gh:104873.)
:data:~typing.ClassVar can now be nested in :data:~typing.Final,
and vice versa.
(Contributed by Mehdi Drissi in :gh:89547.)
Update the Unicode database to version 15.1.0__.
(Contributed by James Gerity in :gh:109559.)
~venv.EnvBuilder and :func:~venv.create),
and opt-out via the CLI, using :option:!--without-scm-ignore-files.
(Contributed by Brett Cannon in :gh:108125.)702: The new :func:warnings.deprecated decorator provides a way to
communicate deprecations to a :term:static type checker
and to warn on usage of deprecated classes and functions.
A :exc:DeprecationWarning may also be emitted when
a decorated function or class is used at runtime.
(Contributed by Jelle Zijlstra in :gh:104003.)Allow controlling Expat >=2.6.0 reparse deferral (:cve:2023-52425)
by adding five new methods:
xml.etree.ElementTree.XMLParser.flushxml.etree.ElementTree.XMLPullParser.flushxml.parsers.expat.xmlparser.GetReparseDeferralEnabledxml.parsers.expat.xmlparser.SetReparseDeferralEnabled!xml.sax.expatreader.ExpatParser.flush(Contributed by Sebastian Pipping in :gh:115623.)
Add the :meth:!close method for the iterator returned by
:func:~xml.etree.ElementTree.iterparse for explicit cleanup.
(Contributed by Serhiy Storchaka in :gh:69893.)
Add support for ZIP64_ format files.
Everybody loves huge data, right?
(Contributed by Tim Hatch in :gh:94146.)
.. _ZIP64: https://en.wikipedia.org/wiki/Zip_(file_format)#ZIP64
Several standard library modules have had
their import times significantly improved.
For example, the import time of the :mod:typing module
has been reduced by around a third by removing dependencies
on :mod:re and :mod:contextlib.
Other modules to enjoy import-time speedups include
:mod:email.utils, :mod:enum, :mod:functools,
:mod:importlib.metadata, and :mod:threading.
(Contributed by Alex Waygood, Shantanu Jain, Adam Turner, Daniel Hollas,
and others in :gh:109653.)
:func:textwrap.indent is now around 30% faster than before for large input.
(Contributed by Inada Naoki in :gh:107369.)
The :mod:subprocess module now uses the :func:~os.posix_spawn function in
more situations, including when close_fds is True (the default)
on many modern platforms.
This should provide a notable performance increase
when launching processes on FreeBSD and Solaris.
See the :ref:subprocess <whatsnew313-subprocess> section above for details.
(Contributed by Jakub Kulik in :gh:113117.)
.. _whatsnew313-pep594:
:pep:594 proposed removing 19 modules from the standard library,
colloquially referred to as 'dead batteries' due to their
historic, obsolete, or insecure status.
All of the following modules were deprecated in Python 3.11,
and are now removed:
:mod:!aifc
standard-aifc:
Use the redistribution of aifc library from PyPI.:mod:!audioop
audioop-lts:
Use audioop-lts library from PyPI.:mod:!chunk
standard-chunk:
Use the redistribution of chunk library from PyPI.:mod:!cgi and :mod:!cgitb
:class:!cgi.FieldStorage can typically be replaced with
:func:urllib.parse.parse_qsl for GET and HEAD requests,
and the :mod:email.message module or the :pypi:multipart library
for POST and PUT requests.
:func:!cgi.parse can be replaced by calling
:func:urllib.parse.parse_qs directly on the desired query string,
unless the input is multipart/form-data,
which should be replaced as described below for :func:!cgi.parse_multipart.
:func:!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:
.. code-block:: python
from email.message import EmailMessage
msg = EmailMessage() msg['content-type'] = 'application/json; charset="utf8"' main, params = msg.get_content_type(), msg['content-type'].params
:func:!cgi.parse_multipart can be replaced with the functionality
in the :mod:email package, which implements the same MIME RFCs,
or with the :pypi:multipart library.
For example, the :class:email.message.EmailMessage
and :class:email.message.Message classes.
:pypi:standard-cgi: and :pypi:standard-cgitb:
Use the redistribution of cgi and cgitb library from PyPI.
:mod:!crypt and the private :mod:!_crypt extension.
The :mod:hashlib module may be an appropriate replacement
when simply hashing a value is required.
Otherwise, various third-party libraries on PyPI are available:
bcrypt:
Modern password hashing for your software and your servers.argon2-cffi:
The secure Argon2 password hashing algorithm.legacycrypt:
:mod:ctypes wrapper to the POSIX crypt library call
and associated functionality.crypt_r:
Fork of the :mod:!crypt module,
wrapper to the :manpage:crypt_r(3) library call
and associated functionality.standard-crypt and :pypi:deprecated-crypt-alternative:
Use the redistribution of crypt and reimplementation of _crypt libraries from PyPI.:mod:!imghdr:
The :pypi:filetype, :pypi:puremagic, or :pypi:python-magic libraries
should be used as replacements.
For example, the :func:!puremagic.what function can be used
to replace the :func:!imghdr.what function for all file formats
that were supported by :mod:!imghdr.
standard-imghdr:
Use the redistribution of imghdr library from PyPI.:mod:!mailcap:
Use the :mod:mimetypes module instead.
standard-mailcap:
Use the redistribution of mailcap library from PyPI.:mod:!msilib
:mod:!nis
:mod:!nntplib:
Use the :pypi:pynntp library from PyPI instead.
standard-nntplib:
Use the redistribution of nntplib library from PyPI.:mod:!ossaudiodev:
For audio playback, use the :pypi:pygame library from PyPI instead.
:mod:!pipes:
Use the :mod:subprocess module instead.
Use :func:shlex.quote to replace the undocumented pipes.quote
function.
standard-pipes:
Use the redistribution of pipes library from PyPI.:mod:!sndhdr:
The :pypi:filetype, :pypi:puremagic, or :pypi:python-magic libraries
should be used as replacements.
standard-sndhdr:
Use the redistribution of sndhdr library from PyPI.:mod:!spwd:
Use the :pypi:python-pam library from PyPI instead.
:mod:!sunau
standard-sunau:
Use the redistribution of sunau library from PyPI.:mod:!telnetlib,
Use the :pypi:telnetlib3 or :pypi:Exscript libraries from PyPI instead.
standard-telnetlib:
Use the redistribution of telnetlib library from PyPI.:mod:!uu:
Use the :mod:base64 module instead, as a modern alternative.
standard-uu:
Use the redistribution of uu library from PyPI.:mod:!xdrlib
standard-xdrlib:
Use the redistribution of xdrlib library from PyPI.(Contributed by Victor Stinner and Zachary Ware in :gh:104773 and :gh:104780.)
2to3 program and the :mod:!lib2to3 module,
previously deprecated in Python 3.11.
(Contributed by Victor Stinner in :gh:104780.)Remove support for chained :class:classmethod descriptors
(introduced in :gh:63272).
These can no longer be used to wrap other descriptors,
such as :class:property.
The core design of this feature was flawed and led to several 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.)
Raise a :exc:RuntimeError when calling :meth:frame.clear
on a suspended frame (as has always been the case for an executing frame).
(Contributed by Irit Katriel in :gh:79932.)
!LegacyInterpolation class,
deprecated in the docstring since Python 3.2,
and at runtime since Python 3.11.
(Contributed by Hugo van Kemenade in :gh:104886.)~object.__getitem__) access for
:ref:EntryPoint <entry-points> objects.
(Contributed by Jason R. Coombs in :gh:113175.)!locale.resetlocale function, deprecated in Python 3.11.
Use locale.setlocale(locale.LC_ALL, "") instead.
(Contributed by Victor Stinner in :gh:104783.)Move :attr:!opcode.ENABLE_SPECIALIZATION to :attr:!_opcode.ENABLE_SPECIALIZATION.
This field was added in 3.12, it was never documented,
and is not intended for external use.
(Contributed by Irit Katriel in :gh:105481.)
Remove :func:!opcode.is_pseudo, :attr:!opcode.MIN_PSEUDO_OPCODE,
and :attr:!opcode.MAX_PSEUDO_OPCODE, which were added in Python 3.12,
but were neither documented nor exposed through :mod:dis,
and were not intended to be used externally.
(Contributed by Irit Katriel in :gh:105481.)
soft deprecated.
While :mod:argparse remains preferred for new projects that
aren't using a third party command line argument processing
library, there are aspects of the way argparse works that
mean the lower level optparse module may provide a better
foundation for writing argument processing libraries, and
for implementing command line applications which adhere more
strictly than argparse does to various Unix command line
processing conventions that originate in the behaviour of the
C :c:func:!getopt function .
(Contributed by Alyssa Coghlan and Serhiy Storchaka in :gh:126180.)~pathlib.Path objects as context managers.
This functionality was deprecated and has had no effect since Python 3.9.
(Contributed by Barney Gale in :gh:83863.)!re.template function and :attr:!re.TEMPLATE / :attr:!re.T flag.
(Contributed by Serhiy Storchaka and Nikita Sobolev in :gh:105687.)!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.)!RawTurtle.settiltangle method,
deprecated in the documentation since Python 3.1
and at runtime since Python 3.11.
(Contributed by Hugo van Kemenade in :gh:104876.)Remove the :mod:!typing.io and :mod:!typing.re namespaces,
deprecated since Python 3.8.
The items in those namespaces can be imported directly
from the :mod:typing module.
(Contributed by Sebastian Rittau in :gh:92871.)
Remove the keyword-argument method of creating
:class:~typing.TypedDict types, deprecated in Python 3.11.
(Contributed by Tomas Roun in :gh:104786.)
Remove the following :mod:unittest functions, deprecated in Python 3.11:
!unittest.findTestCases!unittest.makeSuite!unittest.getTestCaseNamesUse :class:~unittest.TestLoader methods instead:
~unittest.TestLoader.loadTestsFromModule~unittest.TestLoader.loadTestsFromTestCase~unittest.TestLoader.getTestCaseNames(Contributed by Hugo van Kemenade in :gh:104835.)
Remove the untested and undocumented :meth:!TestProgram.usageExit
method, deprecated in Python 3.11.
(Contributed by Hugo van Kemenade in :gh:104992.)
urllib.request.urlopen function, deprecated in Python 3.6.
Use the context parameter instead with an :class:~ssl.SSLContext instance.
The :meth:ssl.SSLContext.load_cert_chain function
can be used to load specific certificates,
or let :func:ssl.create_default_context select
the operating system's trusted certificate authority (CA) certificates.
(Contributed by Victor Stinner in :gh:105382.)Remove the untested and undocumented :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 the deprecated :attr:!MacOSXOSAScript._name attribute.
Use the :attr:MacOSXOSAScript.name <webbrowser.controller.name>
attribute instead.
(Contributed by Nikita Sobolev in :gh:105546.)
:ref:User-defined functions <user-defined-funcs>:
~function.__code__ attribute,
where the new code object's type does not match the function's type.
The different types are:
plain function, generator, async generator, and coroutine.
(Contributed by Irit Katriel in :gh:81137.):mod:array:
'u' format code (:c:type:wchar_t) at runtime.
This format code has been deprecated in documentation since Python 3.3,
and will be removed in Python 3.16.
Use the 'w' format code (:c:type:Py_UCS4)
for Unicode characters instead.
(Contributed by Hugo van Kemenade in :gh:80480.):mod:ctypes:
Deprecate the undocumented :func:!SetPointerType function,
to be removed in Python 3.15.
(Contributed by Victor Stinner in :gh:105733.)
:term:Soft-deprecate <soft deprecated> the :func:~ctypes.ARRAY
function in favour of type * length multiplication.
(Contributed by Victor Stinner in :gh:105733.)
:mod:decimal:
~decimal.Decimal
format specifier 'N',
which is only supported in the :mod:!decimal module's C implementation.
Scheduled to be removed in Python 3.18.
(Contributed by Serhiy Storchaka in :gh:89902.):mod:dis:
!HAVE_ARGUMENT separator.
Check membership in :data:~dis.hasarg instead.
(Contributed by Irit Katriel in :gh:109319.):mod:gettext:
!gettext module,
even if no translation was found.
(Contributed by Serhiy Storchaka in :gh:88434.):mod:glob:
!glob0 and :func:!glob1 functions.
Use :func:~glob.glob and pass a :term:path-like object specifying
the root directory to the root_dir parameter instead.
(Contributed by Barney Gale in :gh:117337.):mod:http.server:
Deprecate :class:!CGIHTTPRequestHandler,
to be removed in Python 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.
(Contributed by Gregory P. Smith in :gh:109096.)
Deprecate the :option:!--cgi flag to
the :program:python -m http.server command-line interface,
to be removed in Python 3.15.
(Contributed by Gregory P. Smith in :gh:109096.)
:mod:mimetypes:
Soft-deprecate <soft deprecated> file path arguments
to :func:~mimetypes.guess_type,
use :func:~mimetypes.guess_file_type instead.
(Contributed by Serhiy Storchaka in :gh:66543.):mod:re:
~re.split, :func:~re.sub, and :func:~re.subn functions.
These parameters will become :ref:keyword-only <keyword-only_parameter>
in a future version of Python.
(Contributed by Serhiy Storchaka in :gh:56166.):mod:pathlib:
!.PurePath.is_reserved,
to be removed in Python 3.15.
Use :func:os.path.isreserved to detect reserved paths on Windows.
(Contributed by Barney Gale in :gh:88569.):mod:platform:
!platform.java_ver,
to be removed in Python 3.15.
This function is only useful for Jython support, has a confusing API,
and is largely untested.
(Contributed by Nikita Sobolev in :gh:116349.):mod:pydoc:
!ispackage function.
(Contributed by Zackery Spytz in :gh:64020.):mod:sqlite3:
Deprecate passing more than one positional argument to
the :func:~sqlite3.connect function
and the :class:~sqlite3.Connection constructor.
The remaining parameters will become keyword-only in Python 3.15.
(Contributed by Erlend E. Aasland in :gh:107948.)
Deprecate passing name, number of arguments, and the callable as keyword
arguments for :meth:.Connection.create_function
and :meth:.Connection.create_aggregate
These parameters will become positional-only in Python 3.15.
(Contributed by Erlend E. Aasland in :gh:108278.)
Deprecate passing the callback callable by keyword for the
:meth:~sqlite3.Connection.set_authorizer,
:meth:~sqlite3.Connection.set_progress_handler, and
:meth:~sqlite3.Connection.set_trace_callback
:class:~sqlite3.Connection methods.
The callback callables will become positional-only in Python 3.15.
(Contributed by Erlend E. Aasland in :gh:108278.)
:mod:sys:
~sys._enablelegacywindowsfsencoding function,
to be removed in Python 3.16.
Use the :envvar:PYTHONLEGACYWINDOWSFSENCODING environment variable instead.
(Contributed by Inada Naoki in :gh:73427.):mod:tarfile:
!TarFile.tarfile attribute,
to be removed in Python 3.16.
(Contributed in :gh:115256.):mod:traceback:
.TracebackException.exc_type attribute.
Use :attr:.TracebackException.exc_type_str instead.
(Contributed by Irit Katriel in :gh:112332.):mod:typing:
Deprecate the undocumented keyword argument syntax for creating
:class:~typing.NamedTuple classes
(e.g. Point = NamedTuple("Point", x=int, y=int)),
to be removed in Python 3.15.
Use the class-based syntax or the functional syntax instead.
(Contributed by Alex Waygood in :gh:105566.)
Deprecate omitting the fields parameter when creating
a :class:~typing.NamedTuple or :class:typing.TypedDict class,
and deprecate passing None to the fields parameter of both types.
Python 3.15 will require a valid sequence for the fields parameter.
To create a NamedTuple class with zero fields,
use class NT(NamedTuple): pass or NT = NamedTuple("NT", ()).
To create a TypedDict class with zero fields,
use class TD(TypedDict): pass or TD = TypedDict("TD", {}).
(Contributed by Alex Waygood in :gh:105566 and :gh:105570.)
Deprecate the :func:!typing.no_type_check_decorator decorator function,
to be removed in Python 3.15.
After eight years in the :mod:typing module,
it has yet to be supported by any major type checker.
(Contributed by Alex Waygood in :gh:106309.)
Deprecate :data:typing.AnyStr.
In Python 3.16, it will be removed from typing.__all__,
and a :exc:DeprecationWarning will be emitted at runtime
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:
getmark(), setmark() and getmarkers() methods of
the :class:~wave.Wave_read and :class:~wave.Wave_write classes,
to be removed in Python 3.15.
(Contributed by Victor Stinner in :gh:105096.).. Add deprecations above alphabetically, not here at the end.
.. include:: ../deprecations/pending-removal-in-3.14.rst
.. include:: ../deprecations/pending-removal-in-3.15.rst
.. include:: ../deprecations/pending-removal-in-3.16.rst
.. include:: ../deprecations/pending-removal-in-3.17.rst
.. include:: ../deprecations/pending-removal-in-3.18.rst
.. include:: ../deprecations/pending-removal-in-3.19.rst
.. include:: ../deprecations/pending-removal-in-3.20.rst
.. include:: ../deprecations/pending-removal-in-future.rst
YIELD_VALUE is now
1 if the yield is part of a yield-from or await, and 0 otherwise.
The oparg of :opcode:RESUME was changed to add a bit indicating
if the except-depth is 1, which is needed to optimize closing of generators.
(Contributed by Irit Katriel in :gh:111354.)Add the :ref:PyMonitoring C API <c-api-monitoring>
for generating :pep:669 monitoring events:
PyMonitoringStatePyMonitoring_FirePyStartEventPyMonitoring_FirePyResumeEventPyMonitoring_FirePyReturnEventPyMonitoring_FirePyYieldEventPyMonitoring_FireCallEventPyMonitoring_FireLineEventPyMonitoring_FireJumpEventPyMonitoring_FireBranchEventPyMonitoring_FireCReturnEventPyMonitoring_FirePyThrowEventPyMonitoring_FireRaiseEventPyMonitoring_FireCRaiseEventPyMonitoring_FireReraiseEventPyMonitoring_FireExceptionHandledEventPyMonitoring_FirePyUnwindEventPyMonitoring_FireStopIterationEventPyMonitoring_EnterScopePyMonitoring_ExitScope(Contributed by Irit Katriel in :gh:111997).
Add :c:type:PyMutex, a lightweight mutex that occupies a single byte,
and the new :c:func:PyMutex_Lock and :c:func:PyMutex_Unlock functions.
:c:func:!PyMutex_Lock will release the :term:GIL (if currently held)
if the operation needs to block.
(Contributed by Sam Gross in :gh:108724.)
Add the :ref:PyTime C API <c-api-time> to provide access to system clocks:
PyTime_t.PyTime_MIN and :c:var:PyTime_MAX.PyTime_AsSecondsDouble.PyTime_Monotonic.PyTime_MonotonicRaw.PyTime_PerfCounter.PyTime_PerfCounterRaw.PyTime_Time.PyTime_TimeRaw.(Contributed by Victor Stinner and Petr Viktorin in :gh:110850.)
Add the :c:func:PyDict_ContainsString function
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.)
Add the :c:func:PyDict_GetItemRef and :c:func:PyDict_GetItemStringRef
functions,
which behave similarly to :c:func:PyDict_GetItemWithError,
but return a :term:strong reference instead of a :term:borrowed reference.
Moreover, these functions return -1 on error,
removing the need to check :c:func:!PyErr_Occurred.
(Contributed by Victor Stinner in :gh:106004.)
Add the :c:func:PyDict_SetDefaultRef function,
which behaves similarly to :c:func:PyDict_SetDefault,
but returns a :term:strong reference instead of a :term:borrowed reference.
This function returns -1 on error,
0 on insertion,
and 1 if the key was already present in the dictionary.
(Contributed by Sam Gross in :gh:112066.)
Add the :c:func:PyDict_Pop and :c:func:PyDict_PopString functions
to remove a key from a dictionary and optionally return the removed value.
This is similar to :meth:dict.pop,
though there is no default value,
and :exc:KeyError is not raised for missing keys.
(Contributed by Stefan Behnel and Victor Stinner in :gh:111262.)
Add the :c:func:PyMapping_GetOptionalItem
and :c:func:PyMapping_GetOptionalItemString functions
as alternatives to :c:func:PyObject_GetItem
and :c:func:PyMapping_GetItemString respectively.
The new functions do not raise :exc:KeyError
if the requested key is missing from the mapping.
These variants are more convenient and faster
if a missing key should not be treated as a failure.
(Contributed by Serhiy Storchaka in :gh:106307.)
Add the :c:func:PyObject_GetOptionalAttr
and :c:func:PyObject_GetOptionalAttrString functions
as alternatives to :c:func:PyObject_GetAttr
and :c:func:PyObject_GetAttrString respectively.
The new functions do not raise :exc:AttributeError
if the requested attribute is not found on the object.
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 the :c:func:PyErr_FormatUnraisable function
as an extension to :c:func:PyErr_WriteUnraisable
that allows customizing the warning message.
(Contributed by Serhiy Storchaka in :gh:108082.)
Add new functions that return a :term:strong reference instead of
a :term:borrowed reference for frame locals, globals, and builtins,
as part of :ref:PEP 667 <whatsnew313-locals-semantics>:
PyEval_GetFrameBuiltins replaces :c:func:PyEval_GetBuiltinsPyEval_GetFrameGlobals replaces :c:func:PyEval_GetGlobalsPyEval_GetFrameLocals replaces :c:func:PyEval_GetLocals(Contributed by Mark Shannon and Tian Gao in :gh:74929.)
Add the :c:func:Py_GetConstant and :c:func:Py_GetConstantBorrowed
functions to get :term:strong <strong reference>
or :term:borrowed <borrowed reference> references to constants.
For example, Py_GetConstant(Py_CONSTANT_ZERO) returns a strong reference
to the constant zero.
(Contributed by Victor Stinner in :gh:115754.)
Add the :c:func:PyImport_AddModuleRef function
as a replacement for :c:func:PyImport_AddModule
that returns a :term:strong reference instead of a :term:borrowed reference.
(Contributed by Victor Stinner in :gh:105922.)
Add the :c:func:Py_IsFinalizing function to check
whether the main Python interpreter is
:term:shutting down <interpreter shutdown>.
(Contributed by Victor Stinner in :gh:108014.)
Add the :c:func:PyList_GetItemRef function
as a replacement for :c:func:PyList_GetItem
that returns a :term:strong reference instead of a :term:borrowed reference.
(Contributed by Sam Gross in :gh:114329.)
Add the :c:func:PyList_Extend and :c:func:PyList_Clear functions,
mirroring the Python :meth:list.extend and :meth:list.clear methods.
(Contributed by Victor Stinner in :gh:111138.)
Add the :c:func:PyLong_AsInt function.
It behaves similarly to :c:func:PyLong_AsLong,
but stores the result in a C :c:expr:int instead of a C :c:expr:long.
(Contributed by Victor Stinner in :gh:108014.)
Add the :c:func:PyLong_AsNativeBytes, :c:func:PyLong_FromNativeBytes,
and :c:func:PyLong_FromUnsignedNativeBytes functions
to simplify converting between native integer types
and Python :class:int objects.
(Contributed by Steve Dower in :gh:111140.)
Add :c:func:PyModule_Add function, which is 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.)
Add the :c:func:PyObject_GenericHash function
that implements the default hashing function of a Python object.
(Contributed by Serhiy Storchaka in :gh:113024.)
Add the :c:func:Py_HashPointer function to hash a raw pointer.
(Contributed by Victor Stinner in :gh:111545.)
Add the :c:func:PyObject_VisitManagedDict and
:c:func:PyObject_ClearManagedDict functions.
which must be called by the traverse and clear functions of a type using
the :c:macro:Py_TPFLAGS_MANAGED_DICT flag.
The pythoncapi-compat project_ can be used to
use these functions with Python 3.11 and 3.12.
(Contributed by Victor Stinner in :gh:107073.)
Add the :c:func:PyRefTracer_SetTracer
and :c:func:PyRefTracer_GetTracer functions,
which enable tracking object creation and destruction
in the same way that the :mod:tracemalloc module does.
(Contributed by Pablo Galindo in :gh:93502.)
Add the :c:func:PySys_AuditTuple function
as an alternative to :c:func:PySys_Audit
that takes event arguments as a Python :class:tuple object.
(Contributed by Victor Stinner in :gh:85283.)
Add the :c:func:PyThreadState_GetUnchecked() function
as an alternative to :c:func:PyThreadState_Get()
that doesn't kill the process with a fatal error if it is NULL.
The caller is responsible for checking if the result is NULL.
(Contributed by Victor Stinner in :gh:108867.)
Add the :c:func:PyType_GetFullyQualifiedName function
to get the type's fully qualified name.
The module name is prepended if :attr:type.__module__ is
a string and is not equal to either 'builtins' or '__main__'.
(Contributed by Victor Stinner in :gh:111696.)
Add the :c:func:PyType_GetModuleName function
to get the type's module name. This is equivalent to getting the
:attr:type.__module__ attribute.
(Contributed by Eric Snow and Victor Stinner in :gh:111696.)
Add the :c:func:PyUnicode_EqualToUTF8AndSize
and :c:func:PyUnicode_EqualToUTF8 functions
to compare a Unicode object with a :c:expr:const char* UTF-8 encoded string
and 1 if they are equal or 0 otherwise.
These functions do not raise exceptions.
(Contributed by Serhiy Storchaka in :gh:110289.)
Add the :c:func:PyWeakref_GetRef function
as an alternative to :c:func:!PyWeakref_GetObject
that returns a :term:strong reference
or NULL if the referent is no longer live.
(Contributed by Victor Stinner in :gh:105927.)
Add fixed variants of functions which silently ignore errors:
PyObject_HasAttrWithError replaces :c:func:PyObject_HasAttr.PyObject_HasAttrStringWithError
replaces :c:func:PyObject_HasAttrString.PyMapping_HasKeyWithError replaces :c:func:PyMapping_HasKey.PyMapping_HasKeyStringWithError
replaces :c:func:PyMapping_HasKeyString.The new functions return -1 for errors
and the standard 1 for true and 0 for false.
(Contributed by Serhiy Storchaka in :gh:108511.)
The keywords parameter of :c:func:PyArg_ParseTupleAndKeywords
and :c:func:PyArg_VaParseTupleAndKeywords
now has type :c:expr:char * const * in C
and :c:expr:const char * const * in C++,
instead of :c:expr:char **.
In C++, this makes these functions compatible with arguments
of type :c:expr:const char * const *, :c:expr:const char **,
or :c:expr:char * const * without an explicit type cast.
In C, the functions only support arguments of type :c:expr:char * const *.
This can be overridden with the :c:macro:PY_CXX_CONST macro.
(Contributed by Serhiy Storchaka in :gh:65210.)
:c:func:PyArg_ParseTupleAndKeywords now supports
non-ASCII keyword parameter names.
(Contributed by Serhiy Storchaka in :gh:110815.)
The :c:func:!PyCode_GetFirstFree function is now unstable API
and is now named :c:func:PyUnstable_Code_GetFirstFree.
(Contributed by Bogdan Romanyuk in :gh:115781.)
The :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 functions,
each of which clears all errors which occurred when calling them
now reports these errors using :func:sys.unraisablehook.
You may replace them with other functions as recommended in the documentation.
(Contributed by Serhiy Storchaka in :gh:106672.)
Add support for the %T, %#T, %N and %#N formats
to :c:func:PyUnicode_FromFormat:
%T: Get the fully qualified name of an object type%#T: As above, but use a colon as the separator%N: Get the fully qualified name of a type%#N: As above, but use a colon as the separatorSee :pep:737 for more information.
(Contributed by Victor Stinner in :gh:111696.)
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.)
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.)
The following functions are now included in the Limited C API:
PyMem_RawMallocPyMem_RawCallocPyMem_RawReallocPyMem_RawFreePySys_AuditPySys_AuditTuplePyType_GetModuleByDef(Contributed by Victor Stinner in :gh:85283 and :gh:116936.)
Python built with :option:--with-trace-refs (tracing references)
now supports the :ref:Limited API <limited-c-api>.
(Contributed by Victor Stinner in :gh:108634.)
Remove several functions, macros, variables, etc
with names prefixed by _Py or _PY (which are considered private).
If your project is affected by one of these removals
and you believe that the removed API should remain available,
please :ref:open a new issue <using-the-tracker> 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 old buffer protocols deprecated in Python 3.0.
Use :ref:bufferobjects instead.
:c:func:!PyObject_CheckReadBuffer:
Use :c:func:PyObject_CheckBuffer to test
whether 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:
Use :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 various functions deprecated in Python 3.9:
:c:func:!PyEval_CallObject, :c:func:!PyEval_CallObjectWithKeywords:
Use :c:func:PyObject_CallNoArgs or :c:func:PyObject_Call instead.
.. warning::
In :c:func:PyObject_Call, positional arguments must be a :class:tuple
and must not be NULL,
and keyword arguments must be a :class:dict or NULL,
whereas the removed functions checked argument types
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>.
:c:func:!PyEval_CallFunction:
Use :c:func:PyObject_CallFunction instead.
:c:func:!PyEval_CallMethod:
Use :c:func:PyObject_CallMethod instead.
:c:func:!PyCFunction_Call:
Use :c:func:PyObject_Call instead.
(Contributed by Victor Stinner in :gh:105107.)
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_SetPath:
Set :c:member:PyConfig.module_search_paths instead.!Py_SetPath:
Set :c:member:PyConfig.module_search_paths 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 :c:func:!PyEval_AcquireLock and :c:func:!PyEval_ReleaseLock functions,
deprecated in Python 3.2.
They didn't update the current thread state.
They can be replaced with:
PyEval_SaveThread and :c:func:PyEval_RestoreThread;PyEval_AcquireThread and :c:func:PyEval_RestoreThread;PyGILState_Ensure and :c:func:PyGILState_Release.(Contributed by Victor Stinner in :gh:105182.)
Remove the :c:func:!PyEval_ThreadsInitialized function,
deprecated in Python 3.9.
Since Python 3.7, :c:func:!Py_Initialize always creates the GIL:
calling :c:func:!PyEval_InitThreads does nothing and
:c:func:!PyEval_ThreadsInitialized always returns non-zero.
(Contributed by Victor Stinner in :gh:105182.)
Remove the :c:func:!_PyInterpreterState_Get alias to
:c:func:PyInterpreterState_Get()
which was kept for backward compatibility with Python 3.8.
The pythoncapi-compat project_ can be used to get
:c:func:PyInterpreterState_Get() on Python 3.8 and older.
(Contributed by Victor Stinner in :gh:106320.)
Remove the private :c:func:!_PyObject_FastCall function:
use :c:func:!PyObject_Vectorcall which is available since Python 3.8
(:pep:590).
(Contributed by Victor Stinner in :gh:106023.)
Remove the cpython/pytime.h header file,
which only contained private functions.
(Contributed by Victor Stinner in :gh:106316.)
Remove the undocumented PY_TIMEOUT_MAX constant from the limited C API.
(Contributed by Victor Stinner in :gh:110014.)
Remove the old trashcan macros Py_TRASHCAN_SAFE_BEGIN
and Py_TRASHCAN_SAFE_END.
Replace both with the new macros Py_TRASHCAN_BEGIN
and Py_TRASHCAN_END.
(Contributed by Irit Katriel in :gh:105111.)
Deprecate old Python initialization functions:
!PySys_ResetWarnOptions:
Clear :data:sys.warnoptions and :data:!warnings.filters instead.!Py_GetExecPrefix:
Get :data:sys.exec_prefix instead.!Py_GetPath:
Get :data:sys.path instead.!Py_GetPrefix:
Get :data:sys.prefix instead.!Py_GetProgramFullPath:
Get :data:sys.executable instead.!Py_GetProgramName:
Get :data:sys.executable instead.!Py_GetPythonHome:
Get :c:member:PyConfig.home
or the :envvar:PYTHONHOME environment variable instead.(Contributed by Victor Stinner in :gh:105145.)
:term:Soft deprecate <soft deprecated> the
:c:func:PyEval_GetBuiltins, :c:func:PyEval_GetGlobals,
and :c:func:PyEval_GetLocals functions,
which return a :term:borrowed reference.
(Soft deprecated as part of :pep:667.)
Deprecate the :c:func:!PyImport_ImportModuleNoBlock function,
which is just an alias to :c:func:PyImport_ImportModule since Python 3.3.
(Contributed by Victor Stinner in :gh:105396.)
:term:Soft deprecate <soft deprecated> the
:c:func:PyModule_AddObject function.
It should be replaced with :c:func:PyModule_Add
or :c:func:PyModule_AddObjectRef.
(Contributed by Serhiy Storchaka in :gh:86493.)
Deprecate the old Py_UNICODE and PY_UNICODE_TYPE types
and the :c:macro:!Py_UNICODE_WIDE define.
Use the :c:type:wchar_t type directly 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 the :c:func:!PyWeakref_GetObject and
:c:func:!PyWeakref_GET_OBJECT functions,
which return a :term:borrowed reference.
Replace them with the new :c:func:PyWeakref_GetRef function,
which returns a :term:strong reference.
The pythoncapi-compat project_ can be used to get
:c:func:PyWeakref_GetRef on Python 3.12 and older.
(Contributed by Victor Stinner in :gh:105927.)
.. Add deprecations above alphabetically, not here at the end.
.. include:: ../deprecations/c-api-pending-removal-in-3.14.rst
.. include:: ../deprecations/c-api-pending-removal-in-3.15.rst
.. include:: ../deprecations/c-api-pending-removal-in-3.16.rst
.. include:: ../deprecations/c-api-pending-removal-in-3.18.rst
.. include:: ../deprecations/c-api-pending-removal-in-future.rst
.. _pythoncapi-compat project: https://github.com/python/pythoncapi-compat/
arm64-apple-ios and arm64-apple-ios-simulator are both
now :pep:11 tier 3 platforms.
(:ref:PEP 730 <whatsnew313-platform-support> written
and implementation contributed by Russell Keith-Magee in :gh:114099.)
aarch64-linux-android and x86_64-linux-android are both
now :pep:11 tier 3 platforms.
(:ref:PEP 738 <whatsnew313-platform-support> written
and implementation contributed by Malcolm Smith in :gh:116622.)
wasm32-wasi is now a :pep:11 tier 2 platform.
(Contributed by Brett Cannon in :gh:115192.)
wasm32-emscripten is no longer a :pep:11 supported platform.
(Contributed by Brett Cannon in :gh:115192.)
Building CPython now requires a compiler with support for the C11 atomic library, GCC built-in atomic functions, or MSVC interlocked intrinsics.
Autoconf 2.71 and aclocal 1.16.5 are now required to regenerate
the :file:configure script.
(Contributed by Christian Heimes in :gh:89886 and by Victor Stinner in :gh:112090.)
SQLite 3.15.2 or newer is required to build
the :mod:sqlite3 extension module.
(Contributed by Erlend Aasland in :gh:105875.)
CPython now bundles the mimalloc library_ by default.
It is licensed under the MIT license;
see :ref:mimalloc license <mimalloc-license>.
The bundled mimalloc has custom changes, see :gh:113141 for details.
(Contributed by Dino Viehland in :gh:109914.)
.. _mimalloc library: https://github.com/microsoft/mimalloc/
The :file:configure option :option:--with-system-libmpdec
now defaults to yes.
The bundled copy of libmpdec will be removed in Python 3.16.
Python built with :file:configure :option:--with-trace-refs
(tracing references) is now ABI compatible with the Python release build
and :ref:debug build <debug-build>.
(Contributed by Victor Stinner in :gh:108634.)
On POSIX systems, the pkg-config (.pc) filenames now include the ABI
flags. For example, the free-threaded build generates python-3.13t.pc
and the debug build generates python-3.13d.pc.
The errno, fcntl, grp, md5, pwd, resource,
termios, winsound,
_ctypes_test, _multiprocessing.posixshmem, _scproxy, _stat,
_statistics, _testconsole, _testimportmultiple and _uuid
C extensions are now built with the :ref:limited C API <limited-c-api>.
(Contributed by Victor Stinner in :gh:85283.)
This section lists previously described changes and other bugfixes that may require changes to your code.
.. _pep667-porting-notes-py:
:ref:PEP 667 <whatsnew313-locals-semantics> introduces several changes
to the semantics of :func:locals and :attr:f_locals <frame.f_locals>:
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 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
passed an explicit namespace to access their results in an optimized scope.
(Changed as part of :pep:667.)
Calling :func:locals from a comprehension at module or class scope
(including via exec or eval) once more behaves as if the comprehension
were running as an independent nested function (i.e. the local variables from
the containing scope are not included). In Python 3.12, this had changed
to include the local variables from the containing scope when implementing
:pep:709. (Changed as part of :pep:667.)
Accessing :attr:FrameType.f_locals <frame.f_locals> in an
:term:optimized scope now returns a write-through proxy rather than a
snapshot that gets updated at ill-specified times. If a snapshot is desired,
it must be created explicitly with dict or the proxy's .copy() method.
(Changed as part of :pep:667.)
:class:functools.partial now emits a :exc:FutureWarning
when used as a method.
The behavior will change in future Python versions.
Wrap it in :func:staticmethod if you want to preserve the old behavior.
(Contributed by Serhiy Storchaka in :gh:121027.)
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 value of the :attr:!mode attribute of :class:gzip.GzipFile
is now a string ('rb' or 'wb') instead of an integer (1 or 2).
The value of the :attr:!mode attribute of the readable file-like object
returned by :meth:zipfile.ZipFile.open is now 'rb' instead of 'r'.
(Contributed by Serhiy Storchaka in :gh:115961.)
:class:mailbox.Maildir now ignores files with a leading dot (.).
(Contributed by Zackery Spytz in :gh:65559.)
:meth:pathlib.Path.glob and :meth:~pathlib.Path.rglob now return both
files and directories if a pattern that ends with "**" is given,
rather than directories only.
Add a trailing slash to keep the previous behavior and only match directories.
The :mod:threading module now expects the :mod:!_thread module
to have an :func:!_is_main_interpreter function.
This function takes no arguments and returns True
if the current interpreter is the main interpreter.
Any library or application that provides a custom :mod:!_thread module
must provide :func:!_is_main_interpreter,
just like the module's other "private" attributes.
(:gh:112826.)
Python.h no longer includes the <ieeefp.h> standard header. It was
included for the :c:func:!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 :c:func:!clock and
:c:func:!gmtime functions, <sys/select.h> provides the :c:func:!select
function, and <sys/time.h> provides the :c:func:!futimes, :c:func:!gettimeofday
and :c:func:!setitimer functions.
(Contributed by Victor Stinner in :gh:108765.)
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 :c:func:!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.)
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. 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.)
.. _pep667-porting-notes-c:
:ref:PEP 667 <whatsnew313-locals-semantics> introduces several changes
to frame-related functions:
The effects of mutating the dictionary returned from
:c:func:PyEval_GetLocals in an :term:optimized scope have changed.
New dict entries added this way will now only be visible to
subsequent :c:func:PyEval_GetLocals calls in that frame,
as :c:func:PyFrame_GetLocals, :func:locals,
and :attr:FrameType.f_locals <frame.f_locals> no longer access
the same underlying cached dictionary.
Changes made to entries for actual variable names and names added via
the write-through proxy interfaces will be overwritten on subsequent calls
to :c:func:PyEval_GetLocals in that frame.
The recommended code update depends on how the function was being used,
so refer to the deprecation notice on the function for details.
Calling :c:func:PyFrame_GetLocals in an :term:optimized scope
now returns a write-through proxy rather than a snapshot
that gets updated at ill-specified times.
If a snapshot is desired, it must be created explicitly
(e.g. with :c:func:PyDict_Copy),
or by calling the new :c:func:PyEval_GetFrameLocals API.
:c:func:!PyFrame_FastToLocals and :c:func:!PyFrame_FastToLocalsWithError
no longer have any effect.
Calling these functions has been redundant since Python 3.11,
when :c:func:PyFrame_GetLocals was first introduced.
:c:func:!PyFrame_LocalsToFast no longer has any effect.
Calling this function is redundant now that :c:func:PyFrame_GetLocals
returns a write-through proxy for :term:optimized scopes <optimized scope>.
Python 3.13 removed many private functions. Some of them can be replaced using these alternatives:
_PyDict_Pop(): :c:func:PyDict_Pop or :c:func:PyDict_PopString;_PyDict_GetItemWithError(): :c:func:PyDict_GetItemRef;_PyErr_WriteUnraisableMsg(): :c:func:PyErr_FormatUnraisable;_PyEval_SetTrace(): :c:func:PyEval_SetTrace or :c:func:PyEval_SetTraceAllThreads;_PyList_Extend(): :c:func:PyList_Extend;_PyLong_AsInt(): :c:func:PyLong_AsInt;_PyMem_RawStrdup(): strdup();_PyMem_Strdup(): strdup();_PyObject_ClearManagedDict(): :c:func:PyObject_ClearManagedDict;_PyObject_VisitManagedDict(): :c:func:PyObject_VisitManagedDict;_PyThreadState_UncheckedGet(): :c:func:PyThreadState_GetUnchecked();_PyTime_AsSecondsDouble(): :c:func:PyTime_AsSecondsDouble;_PyTime_GetMonotonicClock(): :c:func:PyTime_Monotonic or :c:func:PyTime_MonotonicRaw;_PyTime_GetPerfCounter(): :c:func:PyTime_PerfCounter or :c:func:PyTime_PerfCounterRaw;_PyTime_GetSystemClock(): :c:func:PyTime_Time or :c:func:PyTime_TimeRaw;_PyTime_MAX: :c:var:PyTime_MAX;_PyTime_MIN: :c:var:PyTime_MIN;_PyTime_t: :c:type:PyTime_t;_Py_HashPointer(): :c:func:Py_HashPointer;_Py_IsFinalizing(): :c:func:Py_IsFinalizing.The pythoncapi-compat project_ can be used to get most of these new
functions on Python 3.12 and older.
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.)