Fix Cython doesn't support generic types (PEP560)

Watch cython issue #2753
Previous implementation can be used after cython 3.0 release

pydantic/typing.py

@@ -163,6 +163,9 @@ def convert_generics(tp: Type[Any]) -> Type[Any]:
         return tp
 
 else:
+    from typing import _UnionGenericAlias  # type: ignore
+
+    from typing_extensions import _AnnotatedAlias
 
     def convert_generics(tp: Type[Any]) -> Type[Any]:
         """Recursively searches for `str` type hints and replaces them with ForwardRef.
@@ -181,7 +184,7 @@ def convert_generics(tp: Type[Any]) -> Type[Any]:
 
         # typing.Annotated needs special treatment
         if origin is Annotated:
-            return Annotated[(convert_generics(args[0]), *args[1:])]
+            return _AnnotatedAlias(convert_generics(args[0]), args[1:])
 
         # recursively replace `str` isntances inside of `GenericAlias` with `ForwardRef(arg)`
         converted = tuple(
@@ -192,10 +195,10 @@ def convert_generics(tp: Type[Any]) -> Type[Any]:
         if converted == args:
             return tp
         elif isinstance(tp, TypingGenericAlias):
-            return origin[converted]
+            return TypingGenericAlias(origin, converted)
         elif isinstance(tp, TypesUnionType):
-            # recreate types.UnionType (PEP604) with typing.Union
-            return Union[converted]  # type: ignore
+            # recreate types.UnionType (PEP604, Python >= 3.10)
+            return _UnionGenericAlias(origin, converted)
         else:
             try:
                 setattr(tp, '__args__', converted)

tests/test_typing.py

@@ -3,7 +3,9 @@
 from typing import Callable as TypingCallable, Dict, ForwardRef, List, NamedTuple, Union
 
 import pytest
+from typing_extensions import Annotated
 
+from pydantic import Field
 from pydantic.typing import Literal, convert_generics, is_namedtuple, is_none_type, is_typeddict
 
 try:
@@ -86,6 +88,9 @@ def test_convert_generics():
     assert convert_generics(dict['Hero', list['Team']]) == dict[ForwardRef('Hero'), list[ForwardRef('Team')]]
     assert convert_generics(dict['Hero', List['Team']]) == dict[ForwardRef('Hero'), List[ForwardRef('Team')]]
     assert convert_generics(Dict['Hero', list['Team']]) == Dict[ForwardRef('Hero'), list[ForwardRef('Team')]]
+    assert str(convert_generics(Annotated[list['Hero'], Field(min_length=2)])) == str(
+        Annotated[list[ForwardRef('Hero')], Field(min_length=2)]
+    )
 
 
 @pytest.mark.skipif(sys.version_info < (3, 10), reason='PEP604 unions only supported for python 3.10 and above')