1 files changed, 34 insertions, 2 deletions
diff --git a/Lib/test/test_dict.py b/Lib/test/test_dict.py
index 10a6d071b0f..60c62430370 100644
--- a/Lib/test/test_dict.py
+++ b/Lib/test/test_dict.py
@@ -290,6 +290,38 @@ class DictTest(unittest.TestCase):
             ['Cannot convert dictionary update sequence element #0 to a sequence'],
         )
 
+    def test_update_shared_keys(self):
+        class MyClass: pass
+
+        # Subclass str to enable us to create an object during the
+        # dict.update() call.
+        class MyStr(str):
+            def __hash__(self):
+                return super().__hash__()
+
+            def __eq__(self, other):
+                # Create an object that shares the same PyDictKeysObject as
+                # obj.__dict__.
+                obj2 = MyClass()
+                obj2.a = "a"
+                obj2.b = "b"
+                obj2.c = "c"
+                return super().__eq__(other)
+
+        obj = MyClass()
+        obj.a = "a"
+        obj.b = "b"
+
+        x = {}
+        x[MyStr("a")] = MyStr("a")
+
+        # gh-132617: this previously raised "dict mutated during update" error
+        x.update(obj.__dict__)
+
+        self.assertEqual(x, {
+            MyStr("a"): "a",
+            "b": "b",
+        })
 
     def test_fromkeys(self):
         self.assertEqual(dict.fromkeys('abc'), {'a':None, 'b':None, 'c':None})
@@ -787,8 +819,8 @@ class DictTest(unittest.TestCase):
 
     def test_missing(self):
         # Make sure dict doesn't have a __missing__ method
-        self.assertFalse(hasattr(dict, "__missing__"))
-        self.assertFalse(hasattr({}, "__missing__"))
+        self.assertNotHasAttr(dict, "__missing__")
+        self.assertNotHasAttr({}, "__missing__")
         # Test several cases:
         # (D) subclass defines __missing__ method returning a value
         # (E) subclass defines __missing__ method raising RuntimeError