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authorFranek Magiera <framagie@gmail.com>2023-04-26 22:39:39 (GMT)
committerGitHub <noreply@github.com>2023-04-26 22:39:39 (GMT)
commitdc3f97549a8fe4f7fea8d0326e394760b51caa6e (patch)
tree08df1682275e0a96345b6664c26a98c306d1dc51
parenta3a5b4bb232ba29875147baa3b56a5524eece353 (diff)
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gh-103629: Update typing.Unpack docs in compliance with PEP 692 (#103894)
-rw-r--r--Doc/library/typing.rst24
-rw-r--r--Doc/whatsnew/3.12.rst34
-rw-r--r--Misc/NEWS.d/next/Documentation/2023-04-26-23-55-31.gh-issue-103629.-0reqn.rst2
3 files changed, 58 insertions, 2 deletions
diff --git a/Doc/library/typing.rst b/Doc/library/typing.rst
index 15bab77..409a95d 100644
--- a/Doc/library/typing.rst
+++ b/Doc/library/typing.rst
@@ -98,6 +98,9 @@ annotations. These include:
*Introducing* :data:`LiteralString`
* :pep:`681`: Data Class Transforms
*Introducing* the :func:`@dataclass_transform<dataclass_transform>` decorator
+* :pep:`692`: Using ``TypedDict`` for more precise ``**kwargs`` typing
+ *Introducing* a new way of typing ``**kwargs`` with :data:`Unpack` and
+ :data:`TypedDict`
* :pep:`698`: Adding an override decorator to typing
*Introducing* the :func:`@override<override>` decorator
@@ -1417,8 +1420,10 @@ These are not used in annotations. They are building blocks for creating generic
tup: tuple[Unpack[Ts]]
In fact, ``Unpack`` can be used interchangeably with ``*`` in the context
- of types. You might see ``Unpack`` being used explicitly in older versions
- of Python, where ``*`` couldn't be used in certain places::
+ of :class:`typing.TypeVarTuple <TypeVarTuple>` and
+ :class:`builtins.tuple <tuple>` types. You might see ``Unpack`` being used
+ explicitly in older versions of Python, where ``*`` couldn't be used in
+ certain places::
# In older versions of Python, TypeVarTuple and Unpack
# are located in the `typing_extensions` backports package.
@@ -1428,6 +1433,21 @@ These are not used in annotations. They are building blocks for creating generic
tup: tuple[*Ts] # Syntax error on Python <= 3.10!
tup: tuple[Unpack[Ts]] # Semantically equivalent, and backwards-compatible
+ ``Unpack`` can also be used along with :class:`typing.TypedDict` for typing
+ ``**kwargs`` in a function signature::
+
+ from typing import TypedDict, Unpack
+
+ class Movie(TypedDict):
+ name: str
+ year: int
+
+ # This function expects two keyword arguments - `name` of type `str`
+ # and `year` of type `int`.
+ def foo(**kwargs: Unpack[Movie]): ...
+
+ See :pep:`692` for more details on using ``Unpack`` for ``**kwargs`` typing.
+
.. versionadded:: 3.11
.. class:: ParamSpec(name, *, bound=None, covariant=False, contravariant=False)
diff --git a/Doc/whatsnew/3.12.rst b/Doc/whatsnew/3.12.rst
index 8fc95c4..ff631ab 100644
--- a/Doc/whatsnew/3.12.rst
+++ b/Doc/whatsnew/3.12.rst
@@ -66,6 +66,10 @@ Summary -- Release highlights
.. PEP-sized items next.
+New typing features:
+
+* :ref:`whatsnew312-pep692`
+
Important deprecations, removals or restrictions:
* :pep:`623`, Remove wstr from Unicode
@@ -145,6 +149,36 @@ New Features
In Python 3.14, the default will switch to ``'data'``.
(Contributed by Petr Viktorin in :pep:`706`.)
+New Features Related to Type Hints
+==================================
+
+This section covers major changes affecting :pep:`484` type hints and
+the :mod:`typing` module.
+
+.. _whatsnew312-pep692:
+
+PEP 692: Using ``TypedDict`` for more precise ``**kwargs`` typing
+-----------------------------------------------------------------
+
+Typing ``**kwargs`` in a function signature as introduced by :pep:`484` allowed
+for valid annotations only in cases where all of the ``**kwargs`` were of the
+same type.
+
+This PEP specifies a more precise way of typing ``**kwargs`` by relying on
+typed dictionaries::
+
+ from typing import TypedDict, Unpack
+
+ class Movie(TypedDict):
+ name: str
+ year: int
+
+ def foo(**kwargs: Unpack[Movie]): ...
+
+See :pep:`692` for more details.
+
+(PEP written by Franek Magiera)
+
Other Language Changes
======================
diff --git a/Misc/NEWS.d/next/Documentation/2023-04-26-23-55-31.gh-issue-103629.-0reqn.rst b/Misc/NEWS.d/next/Documentation/2023-04-26-23-55-31.gh-issue-103629.-0reqn.rst
new file mode 100644
index 0000000..6dc0a1c
--- /dev/null
+++ b/Misc/NEWS.d/next/Documentation/2023-04-26-23-55-31.gh-issue-103629.-0reqn.rst
@@ -0,0 +1,2 @@
+Mention the new way of typing ``**kwargs`` with ``Unpack`` and ``TypedDict``
+introduced in :pep:`692`.