gh-141510: Change dict_unhashable_type() error message for frozendict (#145085)

Author: vstinner

Lib/test/test_dict.py

@@ -1871,6 +1871,35 @@ def test_pickle_iter(self):
                     self.assertEqual(list(unpickled), expected)
                     self.assertEqual(list(it), expected)
 
+    def test_unhashable_key(self):
+        d = frozendict(a=1)
+        key = [1, 2, 3]
+
+        def check_unhashable_key():
+            msg = "cannot use 'list' as a frozendict key (unhashable type: 'list')"
+            return self.assertRaisesRegex(TypeError, re.escape(msg))
+
+        with check_unhashable_key():
+            key in d
+        with check_unhashable_key():
+            d[key]
+        with check_unhashable_key():
+            d.get(key)
+
+        # Only TypeError exception is overridden,
+        # other exceptions are left unchanged.
+        class HashError:
+            def __hash__(self):
+                raise KeyError('error')
+
+        key2 = HashError()
+        with self.assertRaises(KeyError):
+            key2 in d
+        with self.assertRaises(KeyError):
+            d[key2]
+        with self.assertRaises(KeyError):
+            d.get(key2)
+
 
 if __name__ == "__main__":
     unittest.main()

Objects/dictobject.c

@@ -2377,7 +2377,7 @@ PyDict_GetItem(PyObject *op, PyObject *key)
 }
 
 static void
-dict_unhashable_type(PyObject *key)
+dict_unhashable_type(PyObject *op, PyObject *key)
 {
     PyObject *exc = PyErr_GetRaisedException();
     assert(exc != NULL);
@@ -2386,9 +2386,14 @@ dict_unhashable_type(PyObject *key)
         return;
     }
 
-    PyErr_Format(PyExc_TypeError,
-                 "cannot use '%T' as a dict key (%S)",
-                 key, exc);
+    const char *errmsg;
+    if (PyObject_IsInstance(op, (PyObject*)&PyFrozenDict_Type)) {
+        errmsg = "cannot use '%T' as a frozendict key (%S)";
+    }
+    else {
+        errmsg = "cannot use '%T' as a dict key (%S)";
+    }
+    PyErr_Format(PyExc_TypeError, errmsg, key, exc);
     Py_DECREF(exc);
 }
 
@@ -2401,7 +2406,7 @@ _PyDict_LookupIndexAndValue(PyDictObject *mp, PyObject *key, PyObject **value)
 
     Py_hash_t hash = _PyObject_HashFast(key);
     if (hash == -1) {
-        dict_unhashable_type(key);
+        dict_unhashable_type((PyObject*)mp, key);
         return -1;
     }
 
@@ -2505,7 +2510,7 @@ PyDict_GetItemRef(PyObject *op, PyObject *key, PyObject **result)
 
     Py_hash_t hash = _PyObject_HashFast(key);
     if (hash == -1) {
-        dict_unhashable_type(key);
+        dict_unhashable_type(op, key);
         *result = NULL;
         return -1;
     }
@@ -2521,7 +2526,7 @@ _PyDict_GetItemRef_Unicode_LockHeld(PyDictObject *op, PyObject *key, PyObject **
 
     Py_hash_t hash = _PyObject_HashFast(key);
     if (hash == -1) {
-        dict_unhashable_type(key);
+        dict_unhashable_type((PyObject*)op, key);
         *result = NULL;
         return -1;
     }
@@ -2559,7 +2564,7 @@ PyDict_GetItemWithError(PyObject *op, PyObject *key)
     }
     hash = _PyObject_HashFast(key);
     if (hash == -1) {
-        dict_unhashable_type(key);
+        dict_unhashable_type(op, key);
         return NULL;
     }
 
@@ -2705,7 +2710,7 @@ setitem_take2_lock_held(PyDictObject *mp, PyObject *key, PyObject *value)
 
     Py_hash_t hash = _PyObject_HashFast(key);
     if (hash == -1) {
-        dict_unhashable_type(key);
+        dict_unhashable_type((PyObject*)mp, key);
         Py_DECREF(key);
         Py_DECREF(value);
         return -1;
@@ -2864,7 +2869,7 @@ PyDict_DelItem(PyObject *op, PyObject *key)
     assert(key);
     Py_hash_t hash = _PyObject_HashFast(key);
     if (hash == -1) {
-        dict_unhashable_type(key);
+        dict_unhashable_type(op, key);
         return -1;
     }
 
@@ -3183,7 +3188,7 @@ pop_lock_held(PyObject *op, PyObject *key, PyObject **result)
 
     Py_hash_t hash = _PyObject_HashFast(key);
     if (hash == -1) {
-        dict_unhashable_type(key);
+        dict_unhashable_type(op, key);
         if (result) {
             *result = NULL;
         }
@@ -3596,7 +3601,7 @@ dict_subscript(PyObject *self, PyObject *key)
 
     hash = _PyObject_HashFast(key);
     if (hash == -1) {
-        dict_unhashable_type(key);
+        dict_unhashable_type(self, key);
         return NULL;
     }
     ix = _Py_dict_lookup_threadsafe(mp, key, hash, &value);
@@ -4515,7 +4520,7 @@ dict_get_impl(PyDictObject *self, PyObject *key, PyObject *default_value)
 
     hash = _PyObject_HashFast(key);
     if (hash == -1) {
-        dict_unhashable_type(key);
+        dict_unhashable_type((PyObject*)self, key);
         return NULL;
     }
     ix = _Py_dict_lookup_threadsafe(self, key, hash, &val);
@@ -4547,7 +4552,7 @@ dict_setdefault_ref_lock_held(PyObject *d, PyObject *key, PyObject *default_valu
 
     hash = _PyObject_HashFast(key);
     if (hash == -1) {
-        dict_unhashable_type(key);
+        dict_unhashable_type(d, key);
         if (result) {
             *result = NULL;
         }
@@ -4990,7 +4995,7 @@ dict_contains(PyObject *op, PyObject *key)
 {
     Py_hash_t hash = _PyObject_HashFast(key);
     if (hash == -1) {
-        dict_unhashable_type(key);
+        dict_unhashable_type(op, key);
         return -1;
     }
 
@@ -7066,7 +7071,7 @@ _PyDict_SetItem_LockHeld(PyDictObject *dict, PyObject *name, PyObject *value)
     if (value == NULL) {
         Py_hash_t hash = _PyObject_HashFast(name);
         if (hash == -1) {
-            dict_unhashable_type(name);
+            dict_unhashable_type((PyObject*)dict, name);
             return -1;
         }
         return _PyDict_DelItem_KnownHash_LockHeld((PyObject *)dict, name, hash);