What's new in Python 3.14
****************************
-:Editor: TBD
+:Editor: Hugo van Kemenade
.. Rules for maintenance:
For full details, see the :ref:`changelog <changelog>`.
+.. seealso::
+
+ :pep:`745` -- Python 3.14 release schedule
+
.. note::
Prerelease users should be aware that this document is currently in draft
.. This section singles out the most important changes in Python 3.14.
Brevity is key.
+Python 3.14 beta is the pre-release of the next version of the Python
+programming language, with a mix of changes to the language, the
+implementation and the standard library.
+
+The biggest changes to the implementation include template strings (:pep:`750`),
+deferred evaluation of annotations (:pep:`649`),
+and a new type of interpreter that uses tail calls.
+
+The library changes include the addition of a new :mod:`!annotationlib` module
+for introspecting and wrapping annotations (:pep:`649`),
+a new :mod:`!compression.zstd` module for Zstandard support (:pep:`784`),
+plus syntax highlighting in the REPL,
+as well as the usual deprecations and removals,
+and improvements in user-friendliness and correctness.
.. PEP-sized items next.
* :ref:`PEP 649: deferred evaluation of annotations <whatsnew314-pep649>`
* :ref:`PEP 741: Python Configuration C API <whatsnew314-pep741>`
-* :ref:`PEP 750: Template Strings <whatsnew314-pep750>`
+* :ref:`PEP 750: Template strings <whatsnew314-pep750>`
* :ref:`PEP 758: Allow except and except* expressions without parentheses <whatsnew314-pep758>`
* :ref:`PEP 761: Discontinuation of PGP signatures <whatsnew314-pep761>`
* :ref:`PEP 765: Disallow return/break/continue that exit a finally block <whatsnew314-pep765>`
.. _whatsnew314-pep750:
-PEP 750: Template Strings
+PEP 750: Template strings
-------------------------
Template string literals (t-strings) are a generalization of f-strings,
safe shell operations, improve logging, tackle modern ideas in web development
(HTML, CSS, and so on), and implement lightweight, custom business DSLs.
-See :pep:`750` for more details.
-
(Contributed by Jim Baker, Guido van Rossum, Paul Everitt, Koudai Aono,
Lysandros Nikolaou, Dave Peck, Adam Turner, Jelle Zijlstra, Bénédikt Tran,
and Pablo Galindo Salgado in :gh:`132661`.)
+.. seealso::
+ :pep:`750`.
+
+
.. _whatsnew314-pep768:
PEP 768: Safe external debugger interface for CPython
loop and safe points, ensuring zero overhead during normal execution while providing a reliable way
for external processes to coordinate debugging operations.
-See :pep:`768` for more details.
-
(Contributed by Pablo Galindo Salgado, Matt Wozniski, and Ivona Stojanovic in :gh:`131591`.)
+.. seealso::
+ :pep:`768`.
+
+
.. _whatsnew314-pep784:
PEP 784: Adding Zstandard to the standard library
Victor Stinner, and Rogdham in :gh:`132983`)
.. seealso::
- :pep:`768`.
+ :pep:`784`.
.. _whatsnew314-remote-pdb:
I/O will only work once the next bytecode instruction is executed or when the
process receives a signal.
-This feature leverages :pep:`768` and the :func:`sys.remote_exec` function
+This feature uses :pep:`768` and the :func:`sys.remote_exec` function
to attach to the remote process and send the PDB commands to it.
(Contributed by Matt Wozniski and Pablo Galindo in :gh:`131591`.)
+.. seealso::
+ :pep:`768`.
+
.. _whatsnew314-pep758:
(Contributed by Pablo Galindo and Brett Cannon in :gh:`131831`.)
+.. seealso::
+ :pep:`758`.
+
.. _whatsnew314-pep649:
feature helps programmers quickly identify and fix common typing mistakes. For
example:
- .. code-block:: python
+ .. code-block:: pycon
>>> whille True:
... pass
error message prints the received number of values in more cases than before.
(Contributed by Tushar Sadhwani in :gh:`122239`.)
- .. code-block:: python
+ .. code-block:: pycon
>>> x, y, z = 1, 2, 3, 4
Traceback (most recent call last):
that the string may be intended to be part of the string. (Contributed by
Pablo Galindo in :gh:`88535`.)
- .. code-block:: python
+ .. code-block:: pycon
>>> "The interesting object "The important object" is very important"
Traceback (most recent call last):
^^^^^^
SyntaxError: cannot use subscript as import target
+.. seealso::
+ :pep:`649`.
+
.. _whatsnew314-pep741:
Other language changes
======================
+* The default :term:`interactive` shell now supports import autocompletion.
+ This means that typing ``import foo`` and pressing ``<tab>`` will suggest
+ modules starting with ``foo``. Similarly, typing ``from foo import b`` will
+ suggest submodules of ``foo`` starting with ``b``. Note that autocompletion
+ of module attributes is not currently supported.
+ (Contributed by Tomas Roun in :gh:`69605`.)
+
* The :func:`map` built-in now has an optional keyword-only *strict* flag
like :func:`zip` to check that all the iterables are of equal length.
(Contributed by Wannes Boeykens in :gh:`119793`.)
The testbed can also be used to run the test suite of projects other than
CPython itself. (Contributed by Russell Keith-Magee in :gh:`127592`.)
-* Three-argument :func:`pow` now try calling :meth:`~object.__rpow__` if necessary.
- Previously it was only called in two-argument :func:`!pow` and the binary
- power operator.
+* Three-argument :func:`pow` now tries calling :meth:`~object.__rpow__` if
+ necessary. Previously it was only called in two-argument :func:`!pow` and the
+ binary power operator.
(Contributed by Serhiy Storchaka in :gh:`130104`.)
* Add a built-in implementation for HMAC (:rfc:`2104`) using formally verified
explicitly overridden in the subclass.
(Contributed by Tomasz Pytel in :gh:`132329`.)
-* The command line option :option:`-c` now automatically dedents its code
+* The command-line option :option:`-c` now automatically dedents its code
argument before execution. The auto-dedentation behavior mirrors
:func:`textwrap.dedent`.
(Contributed by Jon Crall and Steven Sun in :gh:`103998`.)
-* Improve error message when an object supporting the synchronous (resp.
- asynchronous) context manager protocol is entered using :keyword:`async
- with` (resp. :keyword:`with`) instead of :keyword:`with` (resp.
- :keyword:`async with`).
+* Improve error message when an object supporting the synchronous
+ context manager protocol is entered using :keyword:`async
+ with` instead of :keyword:`with`.
+ And vice versa with the asynchronous context manager protocol.
(Contributed by Bénédikt Tran in :gh:`128398`.)
* :option:`!-J` is no longer a reserved flag for Jython_,
.. _whatsnew314-pep765:
-PEP 765: Disallow return/break/continue that exit a finally block
------------------------------------------------------------------
+PEP 765: Disallow ``return``/``break``/``continue`` that exit a ``finally`` block
+---------------------------------------------------------------------------------
The compiler emits a :exc:`SyntaxWarning` when a :keyword:`return`, :keyword:`break` or
:keyword:`continue` statements appears where it exits a :keyword:`finally` block.
* Introduced the optional *color* parameter to
:class:`argparse.ArgumentParser`, enabling color for help text.
- This can be controlled via the :envvar:`PYTHON_COLORS` environment
- variable as well as the canonical |NO_COLOR|_
- and |FORCE_COLOR|_ environment variables.
- See also :ref:`using-on-controlling-color`.
+ This can be controlled by :ref:`environment variables
+ <using-on-controlling-color>`. Color has also been enabled for help in the
+ :ref:`stdlib CLIs <library-cmdline>` which use :mod:`!argparse`.
(Contributed by Hugo van Kemenade in :gh:`130645`.)
* By default, today's date is highlighted in color in :mod:`calendar`'s
:ref:`command-line <calendar-cli>` text output.
- This can be controlled via the :envvar:`PYTHON_COLORS` environment
- variable as well as the canonical |NO_COLOR|_
- and |FORCE_COLOR|_ environment variables.
- See also :ref:`using-on-controlling-color`.
+ This can be controlled by :ref:`environment variables
+ <using-on-controlling-color>`.
(Contributed by Hugo van Kemenade in :gh:`128317`.)
------------------
* Add :class:`~concurrent.futures.InterpreterPoolExecutor`,
- which exposes "subinterpreters (multiple Python interpreters in the
+ which exposes "subinterpreters" (multiple Python interpreters in the
same process) to Python code. This is separate from the proposed API
in :pep:`734`.
(Contributed by Eric Snow in :gh:`124548`.)
:class:`~ctypes.c_double_complex` and :class:`~ctypes.c_longdouble_complex`,
are now available if both the compiler and the ``libffi`` library support
complex C types.
- (Contributed by Sergey B Kirpichev in :gh:`61103`).
+ (Contributed by Sergey B Kirpichev in :gh:`61103`.)
* Add :func:`ctypes.util.dllist` for listing the shared libraries
loaded by the current process.
(``_pointer_type_cache``) to the :attr:`ctypes._CData.__pointer_type__`
attribute of the corresponding :mod:`ctypes` types.
This will stop the cache from growing without limits in some situations.
- (Contributed by Sergey Miryanov in :gh:`100926`).
+ (Contributed by Sergey Miryanov in :gh:`100926`.)
* The :class:`ctypes.py_object` type now supports subscription,
making it a :term:`generic type`.
* Allow :meth:`graphlib.TopologicalSorter.prepare` to be called more than once
as long as sorting has not started.
- (Contributed by Daniel Pope in :gh:`130914`)
+ (Contributed by Daniel Pope in :gh:`130914`.)
heapq
.. _whatsnew314-color-json:
-* By default, the output of the :ref:`JSON command-line interface <json-commandline>`
- is highlighted in color. This can be controlled via the
- :envvar:`PYTHON_COLORS` environment variable as well as the canonical
- |NO_COLOR|_ and |FORCE_COLOR|_ environment variables. See also
- :ref:`using-on-controlling-color`.
+* By default, the output of the :ref:`JSON command-line interface
+ <json-commandline>` is highlighted in color.
+ This can be controlled by :ref:`environment variables
+ <using-on-controlling-color>`.
(Contributed by Tomas Roun in :gh:`131952`.)
linecache
* The :ref:`multiprocessing proxy objects <multiprocessing-proxy_objects>`
for *list* and *dict* types gain previously overlooked missing methods:
- * :meth:`!clear` and :meth:`!copy` for proxies of :class:`list`.
+ * :meth:`!clear` and :meth:`!copy` for proxies of :class:`list`
* :meth:`~dict.fromkeys`, ``reversed(d)``, ``d | {}``, ``{} | d``,
- ``d |= {'b': 2}`` for proxies of :class:`dict`.
+ ``d |= {'b': 2}`` for proxies of :class:`dict`
(Contributed by Roy Hyunjin Han for :gh:`103134`.)
(Contributed by Mingyu Park in :gh:`129949`.)
* Add :func:`multiprocessing.Process.interrupt` which terminates the child
- process by sending :py:const:`~signal.SIGINT`. This enables "finally" clauses
- and printing stack trace for the terminated process.
- (Contributed by Artem Pulkin in :gh:`131913`.)
+ process by sending :py:const:`~signal.SIGINT`. This enables
+ :keyword:`finally` clauses to print a stack trace for the terminated
+ process. (Contributed by Artem Pulkin in :gh:`131913`.)
operator
--------
:const:`~socket.BTPROTO_HCI` on Linux.
(Contributed by Serhiy Storchaka in :gh:`70145`.)
* Accept an integer as the address for
- :const:`~socket.BTPROTO_HCI` on Linux
+ :const:`~socket.BTPROTO_HCI` on Linux.
(Contributed by Serhiy Storchaka in :gh:`132099`.)
* Return *cid* in :meth:`~socket.socket.getsockname` for
:const:`~socket.BTPROTO_L2CAP`.
tkinter
-------
-* Make tkinter widget methods :meth:`!after` and :meth:`!after_idle` accept
- arguments passed by keyword.
+* Make :mod:`tkinter` widget methods :meth:`!after` and :meth:`!after_idle`
+ accept arguments passed by keyword.
(Contributed by Zhikang Yan in :gh:`126899`.)
* Add ability to specify name for :class:`!tkinter.OptionMenu` and
--------
* :mod:`unittest` output is now colored by default.
- This can be controlled via the :envvar:`PYTHON_COLORS` environment
- variable as well as the canonical |NO_COLOR|_
- and |FORCE_COLOR|_ environment variables.
- See also :ref:`using-on-controlling-color`.
+ This can be controlled by :ref:`environment variables
+ <using-on-controlling-color>`.
(Contributed by Hugo van Kemenade in :gh:`127221`.)
* unittest discovery supports :term:`namespace package` as start
(Contributed by Inada Naoki in :gh:`133036`.)
* :mod:`ctypes`:
- On non-Windows platforms, setting :attr:`.Structure._pack_` to use a
- MSVC-compatible default memory layout is deprecated in favor of setting
- :attr:`.Structure._layout_` to ``'ms'``.
- (Contributed by Petr Viktorin in :gh:`131747`.)
-* :mod:`ctypes`:
- Calling :func:`ctypes.POINTER` on a string is deprecated.
- Use :ref:`ctypes-incomplete-types` for self-referential structures.
- Also, the internal ``ctypes._pointer_type_cache`` is deprecated.
- See :func:`ctypes.POINTER` for updated implementation details.
- (Contributed by Sergey Myrianov in :gh:`100926`.)
+ * On non-Windows platforms, setting :attr:`.Structure._pack_` to use a
+ MSVC-compatible default memory layout is deprecated in favor of setting
+ :attr:`.Structure._layout_` to ``'ms'``.
+ (Contributed by Petr Viktorin in :gh:`131747`.)
+
+ * Calling :func:`ctypes.POINTER` on a string is deprecated.
+ Use :ref:`ctypes-incomplete-types` for self-referential structures.
+ Also, the internal ``ctypes._pointer_type_cache`` is deprecated.
+ See :func:`ctypes.POINTER` for updated implementation details.
+ (Contributed by Sergey Myrianov in :gh:`100926`.)
* :mod:`functools`:
Calling the Python implementation of :func:`functools.reduce` with *function*
asyncio.run(main())
- If you need to start something, e.g. a server listening on a socket
+ If you need to start something, for example, a server listening on a socket
and then run forever, use :func:`asyncio.run` and an
:class:`asyncio.Event`.
integer must implement either :meth:`~object.__int__` or
:meth:`~object.__index__`. (Contributed by Mark Dickinson in :gh:`119743`.)
-* The default :term:`interactive` shell now supports import autocompletion.
- This means that typing ``import foo`` and pressing ``<tab>`` will suggest
- modules starting with ``foo``. Similarly, typing ``from foo import b`` will
- suggest submodules of ``foo`` starting with ``b``. Note that autocompletion
- of module attributes is not currently supported.
- (Contributed by Tomas Roun in :gh:`69605`.)
-CPython Bytecode Changes
+CPython bytecode changes
========================
* Replaced the opcode ``BINARY_SUBSCR`` by :opcode:`BINARY_OP` with oparg ``NB_SUBSCR``.
* Add a new import and export API for Python :class:`int` objects (:pep:`757`):
- * :c:func:`PyLong_GetNativeLayout`;
- * :c:func:`PyLong_Export`;
- * :c:func:`PyLong_FreeExport`;
- * :c:func:`PyLongWriter_Create`;
- * :c:func:`PyLongWriter_Finish`;
- * :c:func:`PyLongWriter_Discard`.
+ * :c:func:`PyLong_GetNativeLayout`
+ * :c:func:`PyLong_Export`
+ * :c:func:`PyLong_FreeExport`
+ * :c:func:`PyLongWriter_Create`
+ * :c:func:`PyLongWriter_Finish`
+ * :c:func:`PyLongWriter_Discard`
(Contributed by Sergey B Kirpichev and Victor Stinner in :gh:`102471`.)
* Private functions promoted to public C APIs:
- * ``_PyBytes_Join()``: :c:func:`PyBytes_Join`.
- * ``_PyLong_IsNegative()``: :c:func:`PyLong_IsNegative`.
- * ``_PyLong_IsPositive()``: :c:func:`PyLong_IsPositive`.
- * ``_PyLong_IsZero()``: :c:func:`PyLong_IsZero`.
- * ``_PyLong_Sign()``: :c:func:`PyLong_GetSign`.
- * ``_PyUnicodeWriter_Dealloc()``: :c:func:`PyUnicodeWriter_Discard`.
- * ``_PyUnicodeWriter_Finish()``: :c:func:`PyUnicodeWriter_Finish`.
- * ``_PyUnicodeWriter_Init()``: use :c:func:`PyUnicodeWriter_Create`.
- * ``_PyUnicodeWriter_Prepare()``: (no replacement).
- * ``_PyUnicodeWriter_PrepareKind()``: (no replacement).
- * ``_PyUnicodeWriter_WriteChar()``: :c:func:`PyUnicodeWriter_WriteChar`.
- * ``_PyUnicodeWriter_WriteStr()``: :c:func:`PyUnicodeWriter_WriteStr`.
- * ``_PyUnicodeWriter_WriteSubstring()``: :c:func:`PyUnicodeWriter_WriteSubstring`.
- * ``_PyUnicode_EQ()``: :c:func:`PyUnicode_Equal`.
- * ``_PyUnicode_Equal()``: :c:func:`PyUnicode_Equal`.
- * ``_Py_GetConfig()``: :c:func:`PyConfig_Get` and :c:func:`PyConfig_GetInt`.
- * ``_Py_HashBytes()``: :c:func:`Py_HashBuffer`.
- * ``_Py_fopen_obj()``: :c:func:`Py_fopen`.
+ * ``_PyBytes_Join()``: :c:func:`PyBytes_Join`
+ * ``_PyLong_IsNegative()``: :c:func:`PyLong_IsNegative`
+ * ``_PyLong_IsPositive()``: :c:func:`PyLong_IsPositive`
+ * ``_PyLong_IsZero()``: :c:func:`PyLong_IsZero`
+ * ``_PyLong_Sign()``: :c:func:`PyLong_GetSign`
+ * ``_PyUnicodeWriter_Dealloc()``: :c:func:`PyUnicodeWriter_Discard`
+ * ``_PyUnicodeWriter_Finish()``: :c:func:`PyUnicodeWriter_Finish`
+ * ``_PyUnicodeWriter_Init()``: use :c:func:`PyUnicodeWriter_Create`
+ * ``_PyUnicodeWriter_Prepare()``: (no replacement)
+ * ``_PyUnicodeWriter_PrepareKind()``: (no replacement)
+ * ``_PyUnicodeWriter_WriteChar()``: :c:func:`PyUnicodeWriter_WriteChar`
+ * ``_PyUnicodeWriter_WriteStr()``: :c:func:`PyUnicodeWriter_WriteStr`
+ * ``_PyUnicodeWriter_WriteSubstring()``: :c:func:`PyUnicodeWriter_WriteSubstring`
+ * ``_PyUnicode_EQ()``: :c:func:`PyUnicode_Equal`
+ * ``_PyUnicode_Equal()``: :c:func:`PyUnicode_Equal`
+ * ``_Py_GetConfig()``: :c:func:`PyConfig_Get` and :c:func:`PyConfig_GetInt`
+ * ``_Py_HashBytes()``: :c:func:`Py_HashBuffer`
+ * ``_Py_fopen_obj()``: :c:func:`Py_fopen`
The `pythoncapi-compat project`_ can be used to get most of these new
functions on Python 3.13 and older.
projects / thirdparty / Python / cpython.git / commitdiff
