circuitpython/docs/differences/python_310.rst

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.. _python_310:
Python 3.10
===========
Python 3.10.0 (final) was released on the 4 October 2021. The Features for 3.10 are
defined in `PEP 619 <https://www.python.org/dev/peps/pep-0619/#features-for-3-10>`_
and a detailed description of the changes can be found in
`What's New in Python 3.10 <https://docs.python.org/3/whatsnew/3.10.html>`_.
.. table::
:widths: 20 60 20
+--------------------------------------------------------+----------------------------------------------------+--------------+
| **New syntax features** | **Status** |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| `PEP 634 <https://www.python.org/dev/peps/pep-0634/>`_ | Structural Pattern Matching: Specification | [#spm]_ |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| `PEP 635 <https://www.python.org/dev/peps/pep-0635/>`_ | Structural Pattern Matching: Motivation and | [#spm]_ |
| | Rationale | |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| `PEP 636 <https://www.python.org/dev/peps/pep-0636/>`_ | Structural Pattern Matching: Tutorial | [#spm]_ |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| `bpo-12782 | Parenthesized context managers are now officially | |
| <https://github.com/python/cpython/issues/56991>`_ | allowed | |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| **New features in the standard library** |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| `PEP 618 <https://www.python.org/dev/peps/pep-0618/>`_ | Add Optional Length-Checking To zip | |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| **Interpreter improvements** |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| `PEP 626 <https://www.python.org/dev/peps/pep-0626/>`_ | Precise line numbers for debugging and other tools | |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| **New typing features** |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| `PEP 604 <https://www.python.org/dev/peps/pep-0604/>`_ | Allow writing union types as X | Y | |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| `PEP 613 <https://www.python.org/dev/peps/pep-0613/>`_ | Explicit Type Aliases | |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| `PEP 612 <https://www.python.org/dev/peps/pep-0612/>`_ | Parameter Specification Variables | |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| **Important deprecations, removals or restrictions** |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| `PEP 644 <https://www.python.org/dev/peps/pep-0644/>`_ | Require OpenSSL 1.1.1 or newer | |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| `PEP 632 <https://www.python.org/dev/peps/pep-0632/>`_ | Deprecate distutils module. | Not relevant |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| `PEP 623 <https://www.python.org/dev/peps/pep-0623/>`_ | Deprecate and prepare for the removal of the wstr | Not relevant |
| | member in PyUnicodeObject. | |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| `PEP 624 <https://www.python.org/dev/peps/pep-0624/>`_ | Remove Py_UNICODE encoder APIs | Not relevant |
+--------------------------------------------------------+----------------------------------------------------+--------------+
| `PEP 597 <https://www.python.org/dev/peps/pep-0597/>`_ | Add optional EncodingWarning | |
+--------------------------------------------------------+----------------------------------------------------+--------------+
Other Language Changes:
.. table::
:widths: 90 10
+-------------------------------------------------------------------------------------------------------------+---------------+
| The :class:`int` type has a new method :meth:`int.bit_count`, returning the | |
| number of ones in the binary expansion of a given integer, also known | |
| as the population count. | |
+-------------------------------------------------------------------------------------------------------------+---------------+
| The views returned by :meth:`dict.keys`, :meth:`dict.values` and | |
| :meth:`dict.items` now all have a ``mapping`` attribute that gives a | |
| :class:`types.MappingProxyType` object wrapping the original | |
| dictionary. | |
+-------------------------------------------------------------------------------------------------------------+---------------+
| :pep:`618`: The :func:`zip` function now has an optional ``strict`` flag, used | |
| to require that all the iterables have an equal length. | |
+-------------------------------------------------------------------------------------------------------------+---------------+
| Builtin and extension functions that take integer arguments no longer accept | |
| :class:`~decimal.Decimal`\ s, :class:`~fractions.Fraction`\ s and other | |
| objects that can be converted to integers only with a loss (e.g. that have | |
| the :meth:`~object.__int__` method but do not have the | |
| :meth:`~object.__index__` method). | |
+-------------------------------------------------------------------------------------------------------------+---------------+
| If :func:`object.__ipow__` returns :const:`NotImplemented`, the operator will | |
| correctly fall back to :func:`object.__pow__` and :func:`object.__rpow__` as expected. | |
+-------------------------------------------------------------------------------------------------------------+---------------+
| Assignment expressions can now be used unparenthesized within set literals | |
| and set comprehensions, as well as in sequence indexes (but not slices). | |
+-------------------------------------------------------------------------------------------------------------+---------------+
| Functions have a new ``__builtins__`` attribute which is used to look for | |
| builtin symbols when a function is executed, instead of looking into | |
| ``__globals__['__builtins__']``. The attribute is initialized from | |
| ``__globals__["__builtins__"]`` if it exists, else from the current builtins. | |
+-------------------------------------------------------------------------------------------------------------+---------------+
| Two new builtin functions -- :func:`aiter` and :func:`anext` have been added | |
| to provide asynchronous counterparts to :func:`iter` and :func:`next`, | |
| respectively. | |
+-------------------------------------------------------------------------------------------------------------+---------------+
| Static methods (:func:`@staticmethod <staticmethod>`) and class methods | |
| (:func:`@classmethod <classmethod>`) now inherit the method attributes | |
| (``__module__``, ``__name__``, ``__qualname__``, ``__doc__``, | |
| ``__annotations__``) and have a new ``__wrapped__`` attribute. | |
| Moreover, static methods are now callable as regular functions. | |
+-------------------------------------------------------------------------------------------------------------+---------------+
| Annotations for complex targets (everything beside ``simple name`` targets | |
| defined by :pep:`526`) no longer cause any runtime effects with ``from __future__ import annotations``. | |
+-------------------------------------------------------------------------------------------------------------+---------------+
| Class and module objects now lazy-create empty annotations dicts on demand. | |
| The annotations dicts are stored in the objects ``__dict__`` for | |
| backwards compatibility. This improves the best practices for working | |
| with ``__annotations__``. | |
+-------------------------------------------------------------------------------------------------------------+---------------+
| Annotations consist of ``yield``, ``yield from``, ``await`` or named expressions | |
| are now forbidden under ``from __future__ import annotations`` due to their side | |
| effects. | |
+-------------------------------------------------------------------------------------------------------------+---------------+
| Usage of unbound variables, ``super()`` and other expressions that might | |
| alter the processing of symbol table as annotations are now rendered | |
| effectless under ``from __future__ import annotations``. | |
+-------------------------------------------------------------------------------------------------------------+---------------+
| Hashes of NaN values of both :class:`float` type and | |
| :class:`decimal.Decimal` type now depend on object identity. Formerly, they | |
| always hashed to ``0`` even though NaN values are not equal to one another. | |
| This caused potentially quadratic runtime behavior due to excessive hash | |
| collisions when creating dictionaries and sets containing multiple NaNs. | |
+-------------------------------------------------------------------------------------------------------------+---------------+
| A :exc:`SyntaxError` (instead of a :exc:`NameError`) will be raised when deleting | |
| the :const:`__debug__` constant. | |
+-------------------------------------------------------------------------------------------------------------+---------------+
| :exc:`SyntaxError` exceptions now have ``end_lineno`` and | |
| ``end_offset`` attributes. They will be ``None`` if not determined. | |
+-------------------------------------------------------------------------------------------------------------+---------------+
Changes to built-in modules:
.. table::
:widths: 90 10
+---------------------------------------------------------------------------------------------------------------+---------------+
| `asyncio <https://docs.python.org/3/whatsnew/3.10.html#asyncio>`_ |
+---------------------------------------------------------------------------------------------------------------+---------------+
| Add missing :meth:`~asyncio.events.AbstractEventLoop.connect_accepted_socket` | |
| method. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| `array <https://docs.python.org/3/whatsnew/3.10.html#array>`_ |
+---------------------------------------------------------------------------------------------------------------+---------------+
| The :meth:`~array.array.index` method of :class:`array.array` now has | |
| optional *start* and *stop* parameters. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| `gc <https://docs.python.org/3/whatsnew/3.10.html#gc>`_ |
+---------------------------------------------------------------------------------------------------------------+---------------+
| Add audit hooks for :func:`gc.get_objects`, :func:`gc.get_referrers` and | |
| :func:`gc.get_referents`. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| `hashlib <https://docs.python.org/3/whatsnew/3.10.html#hashlib>`_ |
+---------------------------------------------------------------------------------------------------------------+---------------+
| The hashlib module requires OpenSSL 1.1.1 or newer. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| The hashlib module has preliminary support for OpenSSL 3.0.0. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| The pure-Python fallback of :func:`~hashlib.pbkdf2_hmac` is deprecated. In | |
| the future PBKDF2-HMAC will only be available when Python has been built with | |
| OpenSSL support. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| `os <https://docs.python.org/3/whatsnew/3.10.html#os>`_ |
+---------------------------------------------------------------------------------------------------------------+---------------+
| Add :func:`os.cpu_count()` support for VxWorks RTOS. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| Add a new function :func:`os.eventfd` and related helpers to wrap the | |
| ``eventfd2`` syscall on Linux. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| Add :func:`os.splice()` that allows to move data between two file | |
| descriptors without copying between kernel address space and user | |
| address space, where one of the file descriptors must refer to a | |
| pipe. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| Add :data:`~os.O_EVTONLY`, :data:`~os.O_FSYNC`, :data:`~os.O_SYMLINK` | |
| and :data:`~os.O_NOFOLLOW_ANY` for macOS. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| `platform <https://docs.python.org/3/whatsnew/3.10.html#platform>`_ |
+---------------------------------------------------------------------------------------------------------------+---------------+
| Add :func:`platform.freedesktop_os_release()` to retrieve operation system | |
| identification from `freedesktop.org os-release | |
| <https://www.freedesktop.org/software/systemd/man/os-release.html>`_ standard file. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| `socket <https://docs.python.org/3/whatsnew/3.10.html#socket>`_ |
+---------------------------------------------------------------------------------------------------------------+---------------+
| The exception :exc:`socket.timeout` is now an alias of :exc:`TimeoutError`. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| Add option to create MPTCP sockets with ``IPPROTO_MPTCP``. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| Add ``IP_RECVTOS`` option to receive the type of service (ToS) or DSCP/ECN fields. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| `ssl <https://docs.python.org/3/whatsnew/3.10.html#ssl>`_ |
+---------------------------------------------------------------------------------------------------------------+---------------+
| The ssl module requires OpenSSL 1.1.1 or newer. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| The ssl module has preliminary support for OpenSSL 3.0.0 and new option | |
| :data:`~ssl.OP_IGNORE_UNEXPECTED_EOF`. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| Deprecated function and use of deprecated constants now result in | |
| a :exc:`DeprecationWarning`. :attr:`ssl.SSLContext.options` has | |
| :data:`~ssl.OP_NO_SSLv2` and :data:`~ssl.OP_NO_SSLv3` set by default and | |
| therefore cannot warn about setting the flag again. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| The ssl module now has more secure default settings. Ciphers without forward | |
| secrecy or SHA-1 MAC are disabled by default. Security level 2 prohibits | |
| weak RSA, DH, and ECC keys with less than 112 bits of security. | |
| :class:`~ssl.SSLContext` defaults to minimum protocol version TLS 1.2. | |
| Settings are based on Hynek Schlawack's research. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| The deprecated protocols SSL 3.0, TLS 1.0, and TLS 1.1 are no longer | |
| officially supported. Python does not block them actively. However | |
| OpenSSL build options, distro configurations, vendor patches, and cipher | |
| suites may prevent a successful handshake. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| Add a *timeout* parameter to the :func:`ssl.get_server_certificate` function. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| The ssl module uses heap-types and multi-phase initialization. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| A new verify flag :data:`~ssl.VERIFY_X509_PARTIAL_CHAIN` has been added. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| `sys <https://docs.python.org/3/whatsnew/3.10.html#sys>`_ |
+---------------------------------------------------------------------------------------------------------------+---------------+
| Add :data:`sys.orig_argv` attribute: the list of the original command line | |
| arguments passed to the Python executable. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| Add :data:`sys.stdlib_module_names`, containing the list of the standard library | |
| module names. | |
+---------------------------------------------------------------------------------------------------------------+---------------+
| `_thread <https://docs.python.org/3/whatsnew/3.10.html#_thread>`_ |
+---------------------------------------------------------------------------------------------------------------+---------------+
| :func:`_thread.interrupt_main` now takes an optional signal number to | |
| simulate (the default is still :data:`signal.SIGINT`). | |
+---------------------------------------------------------------------------------------------------------------+---------------+
.. rubric:: Notes
.. [#spm] The structural pattern matching feature is discussed in `issue #7847 <https://github.com/micropython/micropython/issues/7847>`_.