diff options
Diffstat (limited to 'Doc/whatsnew/3.9.rst')
| -rw-r--r-- | Doc/whatsnew/3.9.rst | 52 |
1 files changed, 26 insertions, 26 deletions
diff --git a/Doc/whatsnew/3.9.rst b/Doc/whatsnew/3.9.rst index 200d962..690b536 100644 --- a/Doc/whatsnew/3.9.rst +++ b/Doc/whatsnew/3.9.rst @@ -75,27 +75,27 @@ New Features Other Language Changes ====================== -* :func:`builtins.__import__` now raises :exc:`ImportError` instead of - :exc:`ValueError` as used to occur when a relative import went past +* :func:`__import__` now raises :exc:`ImportError` instead of + :exc:`ValueError`, which used to occur when a relative import went past its top-level package. (Contributed by Ngalim Siregar in :issue:`37444`.) * Python now gets the absolute path of the script filename specified on the command line (ex: ``python3 script.py``): the ``__file__`` attribute of - the ``__main__`` module, ``sys.argv[0]`` and ``sys.path[0]`` become an + the :mod:`__main__` module, ``sys.argv[0]`` and ``sys.path[0]`` become an absolute path, rather than a relative path. These paths now remain valid after the current directory is changed by :func:`os.chdir`. As a side effect, - a traceback also displays the absolute path for ``__main__`` module frames in - this case. + a traceback also displays the absolute path for :mod:`__main__` module frames + in this case. (Contributed by Victor Stinner in :issue:`20443`.) * In development mode and in debug build, *encoding* and *errors* arguments are now checked on string encoding and decoding operations. Examples: :func:`open`, :meth:`str.encode` and :meth:`bytes.decode`. - By default, for best performances, the *errors* argument is only checked at - the first encoding/decoding error, and the *encoding* argument is sometimes + By default, for best performance, the *errors* argument is only checked at + the first encoding/decoding error and the *encoding* argument is sometimes ignored for empty strings. (Contributed by Victor Stinner in :issue:`37388`.) @@ -119,15 +119,16 @@ multiline indented output. asyncio ------- -Added a new couroutine :meth:`loop.shutdown_default_executor` that schedules -a shutdown for the default executor that waits on the threadpool to finish -closing. Also, :func:`asyncio.run` has been updated to use the new coroutine. +Added a new :term:`coroutine` :meth:`~asyncio.loop.shutdown_default_executor` +that schedules a shutdown for the default executor that waits on the +:class:`~concurrent.futures.ThreadPoolExecutor` to finish closing. Also, +:func:`asyncio.run` has been updated to use the new :term:`coroutine`. (Contributed by Kyle Stanley in :issue:`34037`.) threading --------- -In a subinterpreter, spawning a daemon thread now raises an exception. Daemon +In a subinterpreter, spawning a daemon thread now raises a :exc:`RuntimeError`. Daemon threads were never supported in subinterpreters. Previously, the subinterpreter finalization crashed with a Python fatal error if a daemon thread was still running. @@ -164,8 +165,8 @@ Optimizations Build and C API Changes ======================= -* Add a new public :c:func:`PyObject_CallNoArgs` function to the C API: - call a callable Python object without any arguments. It is the most efficient +* Add a new public :c:func:`PyObject_CallNoArgs` function to the C API, which + calls a callable Python object without any arguments. It is the most efficient way to call a callable Python object without any argument. (Contributed by Victor Stinner in :issue:`37194`.) @@ -176,18 +177,18 @@ Deprecated * Currently :func:`math.factorial` accepts :class:`float` instances with non-negative integer values (like ``5.0``). It raises a :exc:`ValueError` - for non-integral and negative floats. It is deprecated now. In future + for non-integral and negative floats. It is now deprecated. In future Python versions it will raise a :exc:`TypeError` for all floats. (Contributed by Serhiy Storchaka in :issue:`37315`.) * The :mod:`parser` module is deprecated and will be removed in future versions - of Python. For the majority of use cases users can leverage the Abstract Syntax + of Python. For the majority of use cases, users can leverage the Abstract Syntax Tree (AST) generation and compilation stage, using the :mod:`ast` module. * The :mod:`random` module currently accepts any hashable type as a possible seed value. Unfortunately, some of those types are not guaranteed to have a deterministic hash value. After Python 3.9, - the module will restrict its seeds to *None*, :class:`int`, + the module will restrict its seeds to :const:`None`, :class:`int`, :class:`float`, :class:`str`, :class:`bytes`, and :class:`bytearray`. @@ -195,7 +196,7 @@ Removed ======= * The undocumented ``sys.callstats()`` function has been removed. Since Python - 3.7, it was deprecated and always returned ``None``. It required a special + 3.7, it was deprecated and always returned :const:`None`. It required a special build option ``CALL_PROFILE`` which was already removed in Python 3.7. (Contributed by Victor Stinner in :issue:`37414`.) @@ -213,7 +214,7 @@ Removed (Contributed by Victor Stinner in :issue:`37312`.) * ``aifc.openfp()`` alias to ``aifc.open()``, ``sunau.openfp()`` alias to - ``sunau.open()``, and ``wave.openfp()`` alias to ``wave.open()`` have been + ``sunau.open()``, and ``wave.openfp()`` alias to :func:`wave.open()` have been removed. They were deprecated since Python 3.7. (Contributed by Victor Stinner in :issue:`37320`.) @@ -229,16 +230,16 @@ Removed (Contributed by Serhiy Storchaka in :issue:`36543`.) * The old :mod:`plistlib` API has been removed, it was deprecated since Python - 3.4. Use the :func:`load`, :func:`loads`, :func:`dump`, and :func:`dumps` - functions. Additionally, the ``use_builtin_types`` parameter was removed, - standard :class:`bytes` objects are always used. + 3.4. Use the :func:`~plistlib.load`, :func:`~plistlib.loads`, :func:`~plistlib.dump`, and + :func:`~plistlib.dumps` functions. Additionally, the *use_builtin_types* parameter was + removed, standard :class:`bytes` objects are always used instead. (Contributed by Jon Janzen in :issue:`36409`.) -* ``PyThreadState_DeleteCurrent()`` has been removed. It was not documented. +* The C function ``PyThreadState_DeleteCurrent()`` has been removed. It was not documented. (Contributed by Joannah Nanjekye in :issue:`37878`.) * The C function ``PyGen_NeedsFinalizing`` has been removed. It was not - documented, tested or used anywhere within CPython after the implementation + documented, tested, or used anywhere within CPython after the implementation of :pep:`442`. Patch by Joannah Nanjekye. (Contributed by Joannah Nanjekye in :issue:`15088`) @@ -253,11 +254,10 @@ that may require changes to your code. Changes in the Python API ------------------------- -* :func:`builtins.__import__` and :func:`importlib.util.resolve_name` now raise +* :func:`__import__` and :func:`importlib.util.resolve_name` now raise :exc:`ImportError` where it previously raised :exc:`ValueError`. Callers catching the specific exception type and supporting both Python 3.9 and - earlier versions will need to catch both: - ``except (ImportError, ValueError):`` + earlier versions will need to catch both using ``except (ImportError, ValueError):``. * The :mod:`venv` activation scripts no longer special-case when ``__VENV_PROMPT__`` is set to ``""``. |