- parse_references (message, notmuch_message_get_message_id (message),
- parents, in_reply_to);
-
- /* Carefully avoid adding any self-referential in-reply-to term. */
- in_reply_to_message_id = _parse_message_id (message, in_reply_to, NULL);
- if (in_reply_to_message_id &&
- strcmp (in_reply_to_message_id,
- notmuch_message_get_message_id (message)))
- {
+ in_reply_to_message_id = parse_references (message,
+ this_message_id,
+ parents, in_reply_to);
+
+ /* For the parent of this message, use the last message ID of the
+ * References header, if available. If not, fall back to the
+ * first message ID in the In-Reply-To header. */
+ if (last_ref_message_id) {
+ _notmuch_message_add_term (message, "replyto",
+ last_ref_message_id);
+ } else if (in_reply_to_message_id) {