Issue #25449: Iterating OrderedDict with keys with unstable hash now raises

KeyError in C implementations as well as in Python implementation.

Added tests for OrderedDict subclasses.

Misc/NEWS

@@ -11,6 +11,9 @@ Release date: TBA
 Core and Builtins
 -----------------
 
+- Issue #25449: Iterating OrderedDict with keys with unstable hash now raises
+  KeyError in C implementations as well as in Python implementation.
+
 - Issue #25395: Fixed crash when highly nested OrderedDict structures were
   garbage collected.
 
@@ -333,6 +336,8 @@ Documentation
 Tests
 -----
 
+- Issue #25449: Added tests for OrderedDict subclasses.
+
 - Issue #25099: Make test_compileall not fail when an entry on sys.path cannot
   be written to (commonly seen in administrative installs on Windows).
 

Objects/odictobject.c

@@ -1789,6 +1789,8 @@ odictiter_nextkey(odictiterobject *di)
     /* Get the key. */
     node = _odict_find_node(di->di_odict, di->di_current);
     if (node == NULL) {
+        if (!PyErr_Occurred())
+            PyErr_SetObject(PyExc_KeyError, di->di_current);
         /* Must have been deleted. */
         Py_CLEAR(di->di_current);
         return NULL;