+/* 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;
+}
+