Better error handling and skip compat test cases in 3.13+.

This also fixes the lint errors.

Signed-off-by: Zixuan James Li <[email protected]>

Author: PIG208

src/test_typing_extensions.py

@@ -52,6 +52,9 @@
 # 3.12 changes the representation of Unpack[] (PEP 692)
 TYPING_3_12_0 = sys.version_info[:3] >= (3, 12, 0)
 
+# 3.13 drops support for the keyword argument syntax of TypedDict
+TYPING_3_13_0 = sys.version_info[:3] >= (3, 13, 0)
+
 # https://github.com/python/cpython/pull/27017 was backported into some 3.9 and 3.10
 # versions, but not all
 HAS_FORWARD_MODULE = "module" in inspect.signature(typing._type_check).parameters
@@ -4223,13 +4226,13 @@ class Child(Base):
     def test_extra_key_required(self):
         with self.assertRaisesRegex(
             TypeError,
-            "Special key __extra_items__ does not support Required and NotRequired"
+            "Special key __extra_items__ does not support Required"
         ):
             TypedDict("A", {"__extra_items__": Required[int]}, closed=True)
 
         with self.assertRaisesRegex(
             TypeError,
-            "Special key __extra_items__ does not support Required and NotRequired"
+            "Special key __extra_items__ does not support NotRequired"
         ):
             TypedDict("A", {"__extra_items__": NotRequired[int]}, closed=True)
 
@@ -4318,6 +4321,11 @@ class ChildB(Base, closed=True):
         self.assertEqual(ChildB.__extra_items__, type(None))
         self.assertTrue(ChildB.__closed__)
 
+    skipIf(
+        TYPING_3_13_0,
+        "The keyword argument alternative to define a "
+        "TypedDict type using the functional syntax is no longer supported"
+    )
     def test_backwards_compatibility(self):
         with self.assertWarns(DeprecationWarning):
             TD = TypedDict("TD", closed=int)

src/typing_extensions.py

@@ -930,18 +930,24 @@ def __new__(cls, name, bases, ns, *, total=True, closed=False):
                 optional_keys.update(base_dict.get('__optional_keys__', ()))
                 readonly_keys.update(base_dict.get('__readonly_keys__', ()))
                 mutable_keys.update(base_dict.get('__mutable_keys__', ()))
-                if (base_extra_items_type := base_dict.get('__extra_items__', None)) is not None:
+                base_extra_items_type = base_dict.get('__extra_items__', None)
+                if base_extra_items_type is not None:
                     extra_items_type = base_extra_items_type
-                
+
             if closed and extra_items_type is None:
                 extra_items_type = Never
             if closed and "__extra_items__" in own_annotations:
                 annotation_type = own_annotations.pop("__extra_items__")
                 qualifiers = set(_get_typeddict_qualifiers(annotation_type))
-                if Required in qualifiers or NotRequired in qualifiers:
+                if Required in qualifiers:
+                    raise TypeError(
+                        "Special key __extra_items__ does not support "
+                        "Required"
+                    )
+                if NotRequired in qualifiers:
                     raise TypeError(
                         "Special key __extra_items__ does not support "
-                        "Required and NotRequired"
+                        "NotRequired"
                     )
                 extra_items_type = annotation_type