gh-112618: Make Annotated cache typed

Lib/test/test_typing.py

@@ -8675,6 +8675,34 @@ class X(Annotated[int, (1, 10)]): ...
  self.assertEqual(X.__mro__, (X, int, object),
  "Annotated should be transparent.")
 
+ def test_annotated_cached_with_types(self):
+ class A(str): ...
+ class B(str): ...
+
+ field_a1 = Annotated[str, A("X")]
+ field_a2 = Annotated[str, B("X")]
+
+ self.assertIs(type(field_a1.__metadata__[0]), A)
+ self.assertEqual(field_a1.__metadata__[0], A("X"))
+ self.assertIs(type(field_a2.__metadata__[0]), B)
+ self.assertEqual(field_a2.__metadata__[0], B("X"))
+
+ field_b1 = Annotated[str, A("Y")]
+ field_b2 = Annotated[str, B("Y")]
+
+ self.assertIs(type(field_b1.__metadata__[0]), A)
+ self.assertEqual(field_b1.__metadata__[0], A("Y"))
+ self.assertIs(type(field_b2.__metadata__[0]), B)
+ self.assertEqual(field_b2.__metadata__[0], B("Y"))
+
+ field_c1 = Annotated[int, 1]
+ field_c2 = Annotated[int, 1.0]
+ field_c3 = Annotated[int, True]
+
+ self.assertIs(type(field_c1.__metadata__[0]), int)
+ self.assertIs(type(field_c2.__metadata__[0]), float)
+ self.assertIs(type(field_c3.__metadata__[0]), bool)
+
 
 class TypeAliasTests(BaseTestCase):
  def test_canonical_usage_with_variable_annotation(self):

Lib/typing.py

@@ -490,7 +490,7 @@ def __getitem__(self, parameters):
  return self._getitem(self, parameters)
 
 
-class _LiteralSpecialForm(_SpecialForm, _root=True):
+class _TypedCacheSpecialForm(_SpecialForm, _root=True):
  def __getitem__(self, parameters):
  if not isinstance(parameters, tuple):
  parameters = (parameters,)
@@ -723,7 +723,7 @@ def Optional(self, parameters):
  arg = _type_check(parameters, f"{self} requires a single type.")
  return Union[arg, type(None)]
 
-@_LiteralSpecialForm
+@_TypedCacheSpecialForm
 @_tp_cache(typed=True)
 def Literal(self, *parameters):
  """Special typing form to define literal types (a.k.a. value types).
@@ -2005,8 +2005,9 @@ def __mro_entries__(self, bases):
  return (self.__origin__,)
 
 
-@_SpecialForm
-def Annotated(self, params):
+@_TypedCacheSpecialForm
+@_tp_cache(typed=True)
+def Annotated(self, *params):
  """Add context-specific metadata to a type.
 
  Example: Annotated[int, runtime_check.Unsigned] indicates to the
@@ -2053,7 +2054,7 @@ def Annotated(self, params):
  where T1, T2 etc. are TypeVars, which would be invalid, because
  only one type should be passed to Annotated.
  """
- if not isinstance(params, tuple) or len(params) < 2:
+ if len(params) < 2:
  raise TypeError("Annotated[...] should be used "
  "with at least two arguments (a type and an "
  "annotation).")

Misc/NEWS.d/next/Library/2023-12-02-12-55-17.gh-issue-112618.7_FT8-.rst

@@ -0,0 +1,2 @@
+Fix a caching bug relating to :data:`typing.Annotated`.
+``Annotated[str, True]`` is no longer equal to ``Annotated[str, 1]``.