+ return ret;
+}
+
+/* For each address in 'recipients' that is not configured as one of
+ * the user's addresses in 'config', add that address to 'message' as
+ * an address of 'type'.
+ *
+ * The first address encountered that *is* the user's address will be
+ * returned, (otherwise NULL is returned).
+ */
+static const char *
+add_recipients_for_string (GMimeMessage *message,
+ notmuch_config_t *config,
+ GMimeRecipientType type,
+ const char *recipients)
+{
+ InternetAddressList *list;
+
+ list = internet_address_list_parse_string (recipients);
+ if (list == NULL)
+ return NULL;
+
+ return add_recipients_for_address_list (message, config, type, list);
+}
+
+/* Does the address in the Reply-To header of 'message' already appear
+ * in either the 'To' or 'Cc' header of the message?
+ */
+static int
+reply_to_header_is_redundant (notmuch_message_t *message)
+{
+ const char *header, *addr;
+ InternetAddressList *list;
+ InternetAddress *address;
+ InternetAddressMailbox *mailbox;
+
+ header = notmuch_message_get_header (message, "reply-to");
+ if (*header == '\0')
+ return 0;
+
+ list = internet_address_list_parse_string (header);
+
+ if (internet_address_list_length (list) != 1)
+ return 0;
+
+ address = internet_address_list_get_address (list, 0);
+ if (INTERNET_ADDRESS_IS_GROUP (address))
+ return 0;
+
+ mailbox = INTERNET_ADDRESS_MAILBOX (address);
+ addr = internet_address_mailbox_get_addr (mailbox);
+
+ if (strstr (notmuch_message_get_header (message, "to"), addr) != 0 ||
+ strstr (notmuch_message_get_header (message, "cc"), addr) != 0)
+ {
+ return 1;
+ }
+
+ return 0;
+}
+
+/* Augments the recipients of reply from the headers of message.
+ *
+ * If any of the user's addresses were found in these headers, the first
+ * of these returned, otherwise NULL is returned.
+ */
+static const char *
+add_recipients_from_message (GMimeMessage *reply,
+ notmuch_config_t *config,
+ notmuch_message_t *message)
+{
+ struct {
+ const char *header;
+ const char *fallback;
+ GMimeRecipientType recipient_type;
+ } reply_to_map[] = {
+ { "reply-to", "from", GMIME_RECIPIENT_TYPE_TO },
+ { "to", NULL, GMIME_RECIPIENT_TYPE_TO },
+ { "cc", NULL, GMIME_RECIPIENT_TYPE_CC },
+ { "bcc", NULL, GMIME_RECIPIENT_TYPE_BCC }