qapi: Fix object input visit beyond end of list

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <1488544368-30622-28-git-send-email-armbru@redhat.com>

qapi/qobject-input-visitor.c

@@ -122,10 +122,15 @@ static QObject *qobject_input_try_get_object(QObjectInputVisitor *qiv,
     } else {
         assert(qobject_type(qobj) == QTYPE_QLIST);
         assert(!name);
-        ret = qlist_entry_obj(tos->entry);
-        assert(ret);
+        if (tos->entry) {
+            ret = qlist_entry_obj(tos->entry);
+            if (consume) {
+                tos->entry = qlist_next(tos->entry);
+            }
+        } else {
+            ret = NULL;
+        }
         if (consume) {
-            tos->entry = qlist_next(tos->entry);
             tos->index++;
         }
     }

tests/test-qobject-input-visitor.c

@@ -953,10 +953,8 @@ static void test_visitor_in_fail_list(TestInputVisitorData *data,
     v = visitor_input_test_init(data, "[]");
 
     visit_start_list(v, NULL, NULL, 0, &error_abort);
-#if 0 /* FIXME crash */
     visit_type_int(v, NULL, &i64, &err);
     error_free_or_abort(&err);
-#endif
     visit_end_list(v, NULL);
 }