[Python-checkins] gh-91860: Add docs for typing.dataclass_transform field specifier params (GH-94354) (GH-94372)
ambv
webhook-mailer at python.org
Tue Jun 28 06:10:47 EDT 2022
https://github.com/python/cpython/commit/64365d0df97cbf6c9d75f95234ffb16188e85a18
commit: 64365d0df97cbf6c9d75f95234ffb16188e85a18
branch: 3.11
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: ambv <lukasz at langa.pl>
date: 2022-06-28T12:10:42+02:00
summary:
gh-91860: Add docs for typing.dataclass_transform field specifier params (GH-94354) (GH-94372)
(cherry picked from commit 81ac9ac4921c57c8f31464fed575ea0cfe84df70)
Co-authored-by: Erik De Bonte <erikd at microsoft.com>
files:
M Doc/library/typing.rst
diff --git a/Doc/library/typing.rst b/Doc/library/typing.rst
index c7c5536a64fb4..ddcdc70939f19 100644
--- a/Doc/library/typing.rst
+++ b/Doc/library/typing.rst
@@ -84,6 +84,8 @@ annotations. These include:
*Introducing* :data:`Self`
* :pep:`675`: Arbitrary Literal String Type
*Introducing* :data:`LiteralString`
+* :pep:`681`: Data Class Transforms
+ *Introducing* the :func:`@dataclass_transform<dataclass_transform>` decorator
.. _type-aliases:
@@ -2528,7 +2530,17 @@ Functions and decorators
For example, type checkers will assume these classes have
``__init__`` methods that accept ``id`` and ``name``.
- The arguments to this decorator can be used to customize this behavior:
+ The decorated class, metaclass, or function may accept the following bool
+ arguments which type checkers will assume have the same effect as they
+ would have on the
+ :func:`@dataclasses.dataclass<dataclasses.dataclass>` decorator: ``init``,
+ ``eq``, ``order``, ``unsafe_hash``, ``frozen``, ``match_args``,
+ ``kw_only``, and ``slots``. It must be possible for the value of these
+ arguments (``True`` or ``False``) to be statically evaluated.
+
+ The arguments to the ``dataclass_transform`` decorator can be used to
+ customize the default behaviors of the decorated class, metaclass, or
+ function:
* ``eq_default`` indicates whether the ``eq`` parameter is assumed to be
``True`` or ``False`` if it is omitted by the caller.
@@ -2541,6 +2553,28 @@ Functions and decorators
* Arbitrary other keyword arguments are accepted in order to allow for
possible future extensions.
+ Type checkers recognize the following optional arguments on field
+ specifiers:
+
+ * ``init`` indicates whether the field should be included in the
+ synthesized ``__init__`` method. If unspecified, ``init`` defaults to
+ ``True``.
+ * ``default`` provides the default value for the field.
+ * ``default_factory`` provides a runtime callback that returns the
+ default value for the field. If neither ``default`` nor
+ ``default_factory`` are specified, the field is assumed to have no
+ default value and must be provided a value when the class is
+ instantiated.
+ * ``factory`` is an alias for ``default_factory``.
+ * ``kw_only`` indicates whether the field should be marked as
+ keyword-only. If ``True``, the field will be keyword-only. If
+ ``False``, it will not be keyword-only. If unspecified, the value of
+ the ``kw_only`` parameter on the object decorated with
+ ``dataclass_transform`` will be used, or if that is unspecified, the
+ value of ``kw_only_default`` on ``dataclass_transform`` will be used.
+ * ``alias`` provides an alternative name for the field. This alternative
+ name is used in the synthesized ``__init__`` method.
+
At runtime, this decorator records its arguments in the
``__dataclass_transform__`` attribute on the decorated object.
It has no other runtime effect.
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