* is to find a message ID (or else create one ourselves). */
header = notmuch_message_file_get_header (message_file, "message-id");
- if (header) {
+ if (header && *header != '\0') {
message_id = _parse_message_id (message_file, header, NULL);
/* So the header value isn't RFC-compliant, but it's
* better than no message-id at all. */