(message-idna-to-ascii-rhs-1): Fix previous commit.

(message-idna-to-ascii-rhs): Add a comment.  Suggested by RMS.

diff --git a/lisp/message.el b/lisp/message.el
index 7ab1951..253bee0 100644 (file)
--- a/lisp/message.el
+++ b/lisp/message.el
@@ -5631,14 +5631,13 @@ subscribed address (and not the additional To and Cc header contents)."
       (dolist (rhs
               (mm-delete-duplicates
                (mapcar (lambda (rhs) (or (cadr (split-string rhs "@")) ""))
-                       (mapcar (lambda (domain)
-                                 (if domain
-                                     (downcase domain)
-                                   ""))
+                       (mapcar 'downcase
                                (mapcar
                                 'cadr
                                 (mail-extract-address-components field t))))))
-       (setq ace (if (string-match "\\`[[:ascii:]]+\\'" rhs)
+       ;; Note that `rhs' will be "" if the address does not have
+       ;; the domain part, i.e., if it is a local user's address.
+       (setq ace (if (string-match "\\`[[:ascii:]]*\\'" rhs)
                      rhs
                    (downcase (idna-to-ascii rhs))))
        (when (and (not (equal rhs ace))
@@ -5660,6 +5659,12 @@ See `message-idna-encode'."
   (when message-use-idna
     (save-excursion
       (save-restriction
+       ;; `message-narrow-to-head' that recognizes only the first empty
+       ;; line as the message header separator used to be used here.
+       ;; However, since there is the "--text follows this line--" line
+       ;; normally, it failed in narrowing to the headers and potentially
+       ;; caused the IDNA encoding on lines that look like headers in
+       ;; the message body.
        (message-narrow-to-headers-or-head)
        (message-idna-to-ascii-rhs-1 "From")
        (message-idna-to-ascii-rhs-1 "To")