Add runtime support for pygame.sprite.AbstractGroup subscripts

Author: Matiiss

src_py/sprite.py

@@ -371,6 +371,12 @@ class AbstractGroup:
 
     """
 
+    def __class_getitem__(cls, generic):
+        # switch to `types.GenericAlias` once Python 3.8 support is dropped
+        import typing
+
+        return typing._GenericAlias(cls, generic)  # type: ignore[attr-defined]
+
     # protected identifier value to identify sprite groups, and avoid infinite recursion
     _spritegroup = True
 

test/sprite_test.py

@@ -660,6 +660,19 @@ def update(self, *args, **kwargs):
         self.assertEqual(test_sprite.sink, [1, 2, 3])
         self.assertEqual(test_sprite.sink_kwargs, {"foo": 4, "bar": 5})
 
+    def test_type_subscript(self):
+        try:
+            group_generic_alias = sprite.Group[sprite.Sprite]
+        except TypeError as e:
+            self.fail(e)
+
+        # switch to `types.GenericAlias` once Python 3.8 support is dropped
+        import typing
+
+        self.assertIsInstance(group_generic_alias, typing._GenericAlias)  # type: ignore[attr-defined]
+        self.assertIs(typing.get_origin(group_generic_alias), sprite.Group)
+        self.assertEqual(typing.get_args(group_generic_alias), (sprite.Sprite,))
+
 
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