gh-152358: Fix hash() of annotationlib.ForwardRef with unhashable value

Author: tonghuaroot

Lib/annotationlib.py

@@ -283,10 +283,15 @@ def __eq__(self, other):
                 if isinstance(self.__cell__, dict) and isinstance(other.__cell__, dict)
                 else self.__cell__ is other.__cell__
             )
-            and self.__owner__ == other.__owner__
+            # Owners may be unhashable; __hash__ uses id(), so compare by "is".
+            and self.__owner__ is other.__owner__
+            # Compare extra-name values by identity (see __hash__).
             and (
-                (tuple(sorted(self.__extra_names__.items())) if self.__extra_names__ else None) ==
-                (tuple(sorted(other.__extra_names__.items())) if other.__extra_names__ else None)
+                {n: id(v) for n, v in self.__extra_names__.items()}
+                if self.__extra_names__ else None
+            ) == (
+                {n: id(v) for n, v in other.__extra_names__.items()}
+                if other.__extra_names__ else None
             )
         )
 
@@ -300,8 +305,13 @@ def __hash__(self):
                 tuple(sorted([(name, id(cell)) for name, cell in self.__cell__.items()]))
                 if isinstance(self.__cell__, dict) else id(self.__cell__),
             ),
-            self.__owner__,
-            tuple(sorted(self.__extra_names__.items())) if self.__extra_names__ else None,
+            id(self.__owner__),  # owners may be unhashable, so hash by identity
+            (  # extra-name values may be unhashable, so hash by identity
+                tuple(sorted(
+                    (n, id(v)) for n, v in self.__extra_names__.items()
+                ))
+                if self.__extra_names__ else None
+            ),
         ))
 
     def __or__(self, other):

Lib/test/test_annotationlib.py

@@ -1999,6 +1999,49 @@ def two(_) -> C1 | C2:
         self.assertEqual(A.two_f_ga1, A.two_f_ga2)
         self.assertEqual(hash(A.two_f_ga1), hash(A.two_f_ga2))
 
+    def test_forward_equality_and_hash_with_extra_names(self):
+        """Regression test for the __extra_names__ sibling of GH-143831."""
+        class Unhashable:
+            __hash__ = None
+
+        # An unhashable value referenced in an annotation is kept in the
+        # forward ref's __extra_names__.
+        ns = support.run_code(
+            "def f(a: undefined | obj): pass",
+            extra_names={"obj": Unhashable()},
+        )
+        fr1 = get_annotations(ns["f"], format=Format.FORWARDREF)["a"]
+        fr2 = get_annotations(ns["f"], format=Format.FORWARDREF)["a"]
+        self.assertIsInstance(fr1.__extra_names__, dict)
+
+        self.assertEqual(fr1, fr2)
+        self.assertEqual(hash(fr1), hash(fr2))
+        self.assertEqual(len({fr1, fr2}), 1)
+
+        # Forward refs with different extra-name values are unequal.
+        ns2 = support.run_code(
+            "def g(a: undefined | obj): pass",
+            extra_names={"obj": Unhashable()},
+        )
+        fr3 = get_annotations(ns2["g"], format=Format.FORWARDREF)["a"]
+        self.assertNotEqual(fr1, fr3)
+        self.assertEqual(len({fr1, fr2, fr3}), 2)
+
+    def test_forward_equality_and_hash_with_unhashable_owner(self):
+        """Regression test for an unhashable __owner__ (GH-143831 sibling)."""
+        class MetaNoHash(type):
+            __hash__ = None
+
+        class D(metaclass=MetaNoHash):
+            x: undefined
+
+        fr1 = get_annotations(D, format=Format.FORWARDREF)["x"]
+        fr2 = get_annotations(D, format=Format.FORWARDREF)["x"]
+        self.assertIs(fr1.__owner__, D)
+        self.assertEqual(fr1, fr2)
+        self.assertEqual(hash(fr1), hash(fr2))
+        self.assertEqual(len({fr1, fr2}), 1)
+
     def test_forward_equality_namespace(self):
         def namespace1():
             a = ForwardRef("A")

Misc/NEWS.d/next/Library/2026-06-27-03-20-03.gh-issue-152358.uhR99k.rst

@@ -0,0 +1,3 @@
+Fix :func:`hash` raising :exc:`TypeError` on an
+:class:`annotationlib.ForwardRef` that holds an unhashable value.
+Patch by tonghuaroot.