+static bool
+_parent_via_in_reply_to (notmuch_thread_t *thread, notmuch_message_t *message) {
+ notmuch_message_t *parent;
+ const char *in_reply_to;
+
+ in_reply_to = _notmuch_message_get_in_reply_to (message);
+ THREAD_DEBUG("checking message = %s in_reply_to=%s\n",
+ notmuch_message_get_message_id (message), in_reply_to);
+
+ if (in_reply_to && strlen (in_reply_to) &&
+ g_hash_table_lookup_extended (thread->message_hash,
+ in_reply_to, NULL,
+ (void **) &parent)) {
+ _notmuch_message_add_reply (parent, message);
+ return true;
+ } else {
+ return false;
+ }
+}
+