**************************** 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 `. .. 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 ` 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`.)