cpython/Doc/whatsnew/3.11.rst

****************************
  What's New In Python 3.11
****************************

:Release: |release|
:Date: |today|

.. 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 bug/patch number as a comment:

   XXX Describe the transmogrify() function added to the socket
   module.
   (Contributed by P.Y. Developer in :issue:`12345`.)

   This saves the maintainer the effort of going through the Mercurial log
   when researching a change.

This article explains the new features in Python 3.11, compared to 3.10.

For full details, see the :ref:`changelog <changelog>`.

.. note::

   Prerelease users should be aware that this document is currently in draft
   form. It will be updated substantially as Python 3.11 moves towards release,
   so it's worth checking back even after reading earlier versions.


Summary -- Release highlights
=============================

.. This section singles out the most important changes in Python 3.11.
   Brevity is key.


.. PEP-sized items next.



New Features
============



Other Language Changes
======================



New Modules
===========

* None yet.


Improved Modules
================

fractions
---------

Support :PEP:`515`-style initialization of :class:`~fractions.Fraction` from
string.  (Contributed by Sergey B Kirpichev in :issue:`44258`.)


math
----

* Add :func:`math.cbrt`: return the cube root of x.
  (Contributed by Ajith Ramachandran in :issue:`44357`.)

* The behaviour of two :func:`math.pow` corner cases was changed, for
  consistency with the IEEE 754 specification. The operations
  ``math.pow(0.0, -math.inf)`` and ``math.pow(-0.0, -math.inf)`` now return
  ``inf``. Previously they raised :exc:`ValueError`. (Contributed by Mark
  Dickinson in :issue:`44339`.)


Removed
=======
* :class:`smtpd.MailmanProxy` is now removed as it is unusable without
  an external module, ``mailman``. (Contributed by Dong-hee Na in :issue:`35800`.)


Optimizations
=============

* Compiler now optimizes simple C-style formatting with literal format
  containing only format codes ``%s``, ``%r`` and ``%a`` and makes it as
  fast as corresponding f-string expression.
  (Contributed by Serhiy Storchaka in :issue:`28307`.)

* "Zero-cost" exceptions are implemented. The cost of ``try`` statements is
  almost eliminated when no exception is raised.
  (Contributed by Mark Shannon in :issue:`40222`.)

* Method calls with keywords are now faster due to bytecode
  changes which avoid creating bound method instances. Previously, this
  optimization was applied only to method calls with purely positional
  arguments.
  (Contributed by Ken Jin and Mark Shannon in :issue:`26110`, based on ideas
  implemented in PyPy.)

CPython bytecode changes
========================

* Added a new :opcode:`CALL_METHOD_KW` opcode.  Calls a method in a similar
  fashion as :opcode:`CALL_METHOD`, but also supports keyword arguments.  Works
  in tandem with :opcode:`LOAD_METHOD`.


Build Changes
=============


Deprecated
==========



Removed
=======



Porting to Python 3.11
======================

This section lists previously described changes and other bugfixes
that may require changes to your code.


C API Changes
=============

New Features
------------

Porting to Python 3.11
----------------------

* The :c:func:`PyType_Ready` function now raises an error if a type is defined
  with the :const:`Py_TPFLAGS_HAVE_GC` flag set but has no traverse function
  (:c:member:`PyTypeObject.tp_traverse`).
  (Contributed by Victor Stinner in :issue:`44263`.)

Deprecated
----------

Removed
-------

* :c:func:`PyFrame_BlockSetup` and :c:func:`PyFrame_BlockPop` have been
  removed.
  (Contributed by Mark Shannon in :issue:`40222`.)

* Deprecate the following functions to configure the Python initialization:

  * :c:func:`PySys_AddWarnOptionUnicode`
  * :c:func:`PySys_AddWarnOption`
  * :c:func:`PySys_AddXOption`
  * :c:func:`PySys_HasWarnOptions`
  * :c:func:`Py_SetPath`
  * :c:func:`Py_SetProgramName`
  * :c:func:`Py_SetPythonHome`
  * :c:func:`Py_SetStandardStreamEncoding`
  * :c:func:`_Py_SetProgramFullPath`

  Use the new :c:type:`PyConfig` API of the :ref:`Python Initialization Configuration
  <init-config>` instead (:pep:`587`).
  (Contributed by Victor Stinner in :issue:`44113`.)

* The following deprecated functions and methods are removed in the :mod:`gettext`
  module: :func:`~gettext.lgettext`, :func:`~gettext.ldgettext`,
  :func:`~gettext.lngettext` and :func:`~gettext.ldngettext`.

  Function :func:`~gettext.bind_textdomain_codeset`, methods
  :meth:`~gettext.NullTranslations.output_charset` and
  :meth:`~gettext.NullTranslations.set_output_charset`, and the *codeset*
  parameter of functions :func:`~gettext.translation` and
  :func:`~gettext.install` are also removed, since they are only used for
  the ``l*gettext()`` functions.
  (Contributed by Dong-hee Na and Serhiy Storchaka in :issue:`44235`.)