[3.12] gh-112509: Fix keys being present in both required_keys and optional_keys in TypedDict (GH-112512) (#112530)

(cherry picked from commit 4038869423)

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>

Lib/test/test_typing.py

@@ -7509,6 +7509,46 @@ class TypedDictTests(BaseTestCase):
             'voice': str,
         })
 
+    def test_keys_inheritance_with_same_name(self):
+        class NotTotal(TypedDict, total=False):
+            a: int
+
+        class Total(NotTotal):
+            a: int
+
+        self.assertEqual(NotTotal.__required_keys__, frozenset())
+        self.assertEqual(NotTotal.__optional_keys__, frozenset(['a']))
+        self.assertEqual(Total.__required_keys__, frozenset(['a']))
+        self.assertEqual(Total.__optional_keys__, frozenset())
+
+        class Base(TypedDict):
+            a: NotRequired[int]
+            b: Required[int]
+
+        class Child(Base):
+            a: Required[int]
+            b: NotRequired[int]
+
+        self.assertEqual(Base.__required_keys__, frozenset(['b']))
+        self.assertEqual(Base.__optional_keys__, frozenset(['a']))
+        self.assertEqual(Child.__required_keys__, frozenset(['a']))
+        self.assertEqual(Child.__optional_keys__, frozenset(['b']))
+
+    def test_multiple_inheritance_with_same_key(self):
+        class Base1(TypedDict):
+            a: NotRequired[int]
+
+        class Base2(TypedDict):
+            a: Required[str]
+
+        class Child(Base1, Base2):
+            pass
+
+        # Last base wins
+        self.assertEqual(Child.__annotations__, {'a': Required[str]})
+        self.assertEqual(Child.__required_keys__, frozenset(['a']))
+        self.assertEqual(Child.__optional_keys__, frozenset())
+
     def test_required_notrequired_keys(self):
         self.assertEqual(NontotalMovie.__required_keys__,
                          frozenset({"title"}))