updated for version 7.4.609
Problem:    For complicated list and dict use the garbage collector can run
            out of stack space.
Solution:   Use a stack of dicts and lists to be marked, thus making it
            iterative instead of recursive. (Ben Fritz)
diff --git a/src/if_py_both.h b/src/if_py_both.h
index 206d298..a46b42a 100644
--- a/src/if_py_both.h
+++ b/src/if_py_both.h
@@ -5502,34 +5502,41 @@
     PyErr_Clear();
 }
 
-    static void
+    static int
 set_ref_in_py(const int copyID)
 {
     pylinkedlist_T	*cur;
     dict_T	*dd;
     list_T	*ll;
+    int		abort = FALSE;
 
     if (lastdict != NULL)
-	for(cur = lastdict ; cur != NULL ; cur = cur->pll_prev)
+    {
+	for(cur = lastdict ; !abort && cur != NULL ; cur = cur->pll_prev)
 	{
 	    dd = ((DictionaryObject *) (cur->pll_obj))->dict;
 	    if (dd->dv_copyID != copyID)
 	    {
 		dd->dv_copyID = copyID;
-		set_ref_in_ht(&dd->dv_hashtab, copyID);
+		abort = abort || set_ref_in_ht(&dd->dv_hashtab, copyID, NULL);
 	    }
 	}
+    }
 
     if (lastlist != NULL)
-	for(cur = lastlist ; cur != NULL ; cur = cur->pll_prev)
+    {
+	for(cur = lastlist ; !abort && cur != NULL ; cur = cur->pll_prev)
 	{
 	    ll = ((ListObject *) (cur->pll_obj))->list;
 	    if (ll->lv_copyID != copyID)
 	    {
 		ll->lv_copyID = copyID;
-		set_ref_in_list(ll, copyID);
+		abort = abort || set_ref_in_list(ll, copyID, NULL);
 	    }
 	}
+    }
+
+    return abort;
 }
 
     static int