patch 7.4.1719
Problem:    Leaking memory when there is a cycle involving a job and a
            partial.
Solution:   Add a copyID to job and channel.  Set references in items referred
            by them.  Go through all jobs and channels to find unreferenced
            items.  Also, decrement reference counts when garbage collecting.
diff --git a/src/ops.c b/src/ops.c
index b1910d9..0584877 100644
--- a/src/ops.c
+++ b/src/ops.c
@@ -6391,7 +6391,7 @@
 	{
 	    if (list_append_string(list, NULL, -1) == FAIL)
 	    {
-		list_free(list, TRUE);
+		list_free(list);
 		return NULL;
 	    }
 	    list->lv_first->li_tv.vval.v_string = s;
@@ -6465,7 +6465,7 @@
 		error = TRUE;
 	if (error)
 	{
-	    list_free(list, TRUE);
+	    list_free(list);
 	    return NULL;
 	}
 	return (char_u *)list;