Backport of python/cpython#109544

Co-authored-by: Jelle Zijlstra <[email protected]>

Author: Daraan

src/test_typing_extensions.py

@@ -4148,6 +4148,17 @@ def test_total(self):
         self.assertEqual(Options.__required_keys__, frozenset())
         self.assertEqual(Options.__optional_keys__, {'log_level', 'log_path'})
 
+    def test_total_inherits_non_total(self):
+        class TD1(TypedDict, total=False):
+            a: int
+
+        self.assertIs(TD1.__total__, False)
+
+        class TD2(TD1):
+            b: str
+
+        self.assertIs(TD2.__total__, True)
+
     def test_optional_keys(self):
         class Point2Dor3D(Point2D, total=False):
             z: int

src/typing_extensions.py

@@ -1029,8 +1029,6 @@ def __new__(cls, name, bases, ns, *, total=True, closed=False):
             tp_dict.__optional_keys__ = frozenset(optional_keys)
             tp_dict.__readonly_keys__ = frozenset(readonly_keys)
             tp_dict.__mutable_keys__ = frozenset(mutable_keys)
-            if not hasattr(tp_dict, '__total__'):
-                tp_dict.__total__ = total
             tp_dict.__closed__ = closed
             tp_dict.__extra_items__ = extra_items_type
             return tp_dict