diff --git a/Doc/library/typing.rst b/Doc/library/typing.rst index 9007c0daf59a4d..fe0f475a492cd7 100644 --- a/Doc/library/typing.rst +++ b/Doc/library/typing.rst @@ -1389,11 +1389,20 @@ These are not used in annotations. They are building blocks for declaring types. ``Point2D.__optional_keys__``. To allow using this feature with older versions of Python that do not support :pep:`526`, ``TypedDict`` supports two additional equivalent - syntactic forms:: + syntactic forms: + + * Using a literal :class:`dict` as the second argument:: - Point2D = TypedDict('Point2D', x=int, y=int, label=str) Point2D = TypedDict('Point2D', {'x': int, 'y': int, 'label': str}) + * Using keyword arguments:: + + Point2D = TypedDict('Point2D', x=int, y=int, label=str) + + .. deprecated-removed:: 3.11 3.13 + The keyword-argument syntax is deprecated in 3.11 and will be removed + in 3.13. It may also be unsupported by static type checkers. + By default, all keys must be present in a ``TypedDict``. It is possible to override this by specifying totality. Usage:: @@ -1402,6 +1411,9 @@ These are not used in annotations. They are building blocks for declaring types. x: int y: int + # Alternative syntax + Point2D = TypedDict('Point2D', {'x': int, 'y': int}, total=False) + This means that a ``Point2D`` ``TypedDict`` can have any of the keys omitted. A type checker is only expected to support a literal ``False`` or ``True`` as the value of the ``total`` argument. ``True`` is the default, diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py index 85f74064458f2d..b0754c9500edb9 100644 --- a/Lib/test/test_typing.py +++ b/Lib/test/test_typing.py @@ -4300,7 +4300,8 @@ def test_basics_functional_syntax(self): self.assertEqual(Emp.__total__, True) def test_basics_keywords_syntax(self): - Emp = TypedDict('Emp', name=str, id=int) + with self.assertWarns(DeprecationWarning): + Emp = TypedDict('Emp', name=str, id=int) self.assertIsSubclass(Emp, dict) self.assertIsSubclass(Emp, typing.MutableMapping) self.assertNotIsSubclass(Emp, collections.abc.Sequence) @@ -4315,7 +4316,8 @@ def test_basics_keywords_syntax(self): self.assertEqual(Emp.__total__, True) def test_typeddict_special_keyword_names(self): - TD = TypedDict("TD", cls=type, self=object, typename=str, _typename=int, fields=list, _fields=dict) + with self.assertWarns(DeprecationWarning): + TD = TypedDict("TD", cls=type, self=object, typename=str, _typename=int, fields=list, _fields=dict) self.assertEqual(TD.__name__, 'TD') self.assertEqual(TD.__annotations__, {'cls': type, 'self': object, 'typename': str, '_typename': int, 'fields': list, '_fields': dict}) a = TD(cls=str, self=42, typename='foo', _typename=53, fields=[('bar', tuple)], _fields={'baz', set}) @@ -4371,7 +4373,7 @@ def test_py36_class_syntax_usage(self): def test_pickle(self): global EmpD # pickle wants to reference the class by name - EmpD = TypedDict('EmpD', name=str, id=int) + EmpD = TypedDict('EmpD', {'name': str, 'id': int}) jane = EmpD({'name': 'jane', 'id': 37}) for proto in range(pickle.HIGHEST_PROTOCOL + 1): z = pickle.dumps(jane, proto) @@ -4383,7 +4385,7 @@ def test_pickle(self): self.assertEqual(EmpDnew({'name': 'jane', 'id': 37}), jane) def test_optional(self): - EmpD = TypedDict('EmpD', name=str, id=int) + EmpD = TypedDict('EmpD', {'name': str, 'id': int}) self.assertEqual(typing.Optional[EmpD], typing.Union[None, EmpD]) self.assertNotEqual(typing.List[EmpD], typing.Tuple[EmpD]) diff --git a/Lib/typing.py b/Lib/typing.py index 0cf9755022e9b8..4189771e673a31 100644 --- a/Lib/typing.py +++ b/Lib/typing.py @@ -2399,9 +2399,8 @@ class Point2D(TypedDict): The type info can be accessed via the Point2D.__annotations__ dict, and the Point2D.__required_keys__ and Point2D.__optional_keys__ frozensets. - TypedDict supports two additional equivalent forms:: + TypedDict supports an additional equivalent form:: - Point2D = TypedDict('Point2D', x=int, y=int, label=str) Point2D = TypedDict('Point2D', {'x': int, 'y': int, 'label': str}) By default, all keys must be present in a TypedDict. It is possible @@ -2417,14 +2416,22 @@ class point2D(TypedDict, total=False): the total argument. True is the default, and makes all items defined in the class body be required. - The class syntax is only supported in Python 3.6+, while two other - syntax forms work for Python 2.7 and 3.2+ + The class syntax is only supported in Python 3.6+, while the other + syntax form works for Python 2.7 and 3.2+ """ if fields is None: fields = kwargs elif kwargs: raise TypeError("TypedDict takes either a dict or keyword arguments," " but not both") + if kwargs: + warnings.warn( + "The kwargs-based syntax for TypedDict definitions is deprecated " + "in Python 3.11, will be removed in Python 3.13, and may not be " + "understood by third-party type checkers.", + DeprecationWarning, + stacklevel=2, + ) ns = {'__annotations__': dict(fields)} module = _caller() diff --git a/Misc/ACKS b/Misc/ACKS index 6df339c3e145bf..eaaaf7259dc192 100644 --- a/Misc/ACKS +++ b/Misc/ACKS @@ -1973,6 +1973,7 @@ Arnon Yaari Alakshendra Yadav Hirokazu Yamamoto Masayuki Yamamoto +Jingchen Ye Ka-Ping Yee Chi Hsuan Yen Jason Yeo diff --git a/Misc/NEWS.d/next/Library/2022-02-08-16-42-20.bpo-46066.m32Hl0.rst b/Misc/NEWS.d/next/Library/2022-02-08-16-42-20.bpo-46066.m32Hl0.rst new file mode 100644 index 00000000000000..d13d9421e748b8 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2022-02-08-16-42-20.bpo-46066.m32Hl0.rst @@ -0,0 +1,3 @@ +Deprecate kwargs-based syntax for :class:`typing.TypedDict` definitions. +It had confusing semantics when specifying totality, and was largely unused. +Patch by Jingchen Ye. pFad - Phonifier reborn

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