Issue #28189: dictitems_contains no longer swallows compare errors.

 (Patch by Xiang Zhang)

Lib/test/test_dictviews.py

@@ -209,6 +209,32 @@ class DictSetTest(unittest.TestCase):
         self.assertRaises(TypeError, copy.copy, d.values())
         self.assertRaises(TypeError, copy.copy, d.items())
 
+    def test_compare_error(self):
+        class Exc(Exception):
+            pass
+
+        class BadEq:
+            def __hash__(self):
+                return 7
+            def __eq__(self, other):
+                raise Exc
+
+        k1, k2 = BadEq(), BadEq()
+        v1, v2 = BadEq(), BadEq()
+        d = {k1: v1}
+
+        self.assertIn(k1, d)
+        self.assertIn(k1, d.keys())
+        self.assertIn(v1, d.values())
+        self.assertIn((k1, v1), d.items())
+
+        self.assertRaises(Exc, d.__contains__, k2)
+        self.assertRaises(Exc, d.keys().__contains__, k2)
+        self.assertRaises(Exc, d.items().__contains__, (k2, v1))
+        self.assertRaises(Exc, d.items().__contains__, (k1, v2))
+        with self.assertRaises(Exc):
+            v2 in d.values()
+
     def test_pickle(self):
         d = {1: 10, "a": "ABC"}
         for proto in range(pickle.HIGHEST_PROTOCOL + 1):

Misc/NEWS

@@ -19,6 +19,9 @@ Core and Builtins
 - Issue #25758: Prevents zipimport from unnecessarily encoding a filename
   (patch by Eryk Sun)
 
+- Issue #28189: dictitems_contains no longer swallows compare errors.
+  (Patch by Xiang Zhang)
+
 - Issue #27812: Properly clear out a generator's frame's backreference to the
   generator to prevent crashes in frame.clear().
 

Objects/dictobject.c

@@ -3654,7 +3654,7 @@ dictitems_contains(_PyDictViewObject *dv, PyObject *obj)
         return 0;
     key = PyTuple_GET_ITEM(obj, 0);
     value = PyTuple_GET_ITEM(obj, 1);
-    found = PyDict_GetItem((PyObject *)dv->dv_dict, key);
+    found = PyDict_GetItemWithError((PyObject *)dv->dv_dict, key);
     if (found == NULL) {
         if (PyErr_Occurred())
             return -1;