bug#12439: 24.2.50; mail-abbrev fills long aliasee uglily

[Katsumi Yamaoka]

Hi,

By default message.el uses mail-abbrev to expand mail aliases in
headers in a draft.  If an aliasee is longer than fill-column,
it will be expanded like the following:

To: foo1@bar.baz, foo2@bar.baz, foo3@bar.baz, foo4@bar.baz,
    foo5@bar.baz,
    foo6@bar.baz,
    foo7@bar.baz,
    foo8@bar.baz

To reproduce this, try the "foo" alias specified as follows:

(define-mail-abbrev "foo"
  "foo1@bar.baz, foo2@bar.baz, foo3@bar.baz, foo4@bar.baz,\
 foo5@bar.baz, foo6@bar.baz, foo7@bar.baz, foo8@bar.baz")

The point is that the latter half addresses in an aliasee are
put line by line.  Moreover, I think a SPC is enough for LWSP
preceding to the latter half (message.el uses TAB in some fill
function, though), rather than the one indent-relative generates.

A patch I tried is attached below.

--- mailabbrev.el~      2012-05-06 21:58:55.506179000 +0000
+++ mailabbrev.el       2012-09-14 08:38:38.323389500 +0000
@@ -391,35 +391,24 @@
 (defun mail-abbrev-expand-hook ()
   "For use as the fourth arg to `define-abbrev'.
 After expanding a mail-abbrev, if Auto Fill mode is on and we're past the
-fill-column, break the line at the previous comma, and indent the next line."
-  ;; Disable abbrev mode to avoid recursion in indent-relative expanding
-  ;; part of the abbrev expansion as an abbrev itself.
-  (let ((abbrev-mode nil))
-    (save-excursion
-      (let ((p (point))
-           bol comma fp)
-       (beginning-of-line)
-       (setq bol (point))
-       (goto-char p)
-       (while (and auto-fill-function
-                   (>= (current-column) fill-column)
-                   (search-backward "," bol t))
-         (setq comma (point))
-         (forward-char 1)              ; Now we are just past the comma.
-         (insert "\n")
-         (delete-horizontal-space)
-         (setq p (point))
-         (indent-relative)
-         (setq fp (buffer-substring p (point)))
-         ;; Go to the end of the new line.
-         (end-of-line)
-         (if (> (current-column) fill-column)
-             ;; It's still too long; do normal auto-fill.
-             (let ((fill-prefix (or fp "\t")))
-               (do-auto-fill)))
-         ;; Resume the search.
-         (goto-char comma)
-         )))))
+fill-column, break the line at the previous comma, and indent the next line
+with a space."
+  (when auto-fill-function
+    (let (p)
+      (save-excursion
+       (while (>= (current-column) fill-column)
+         (while (and (search-backward "," (point-at-bol) 'move)
+                     (>= (current-column) (1- fill-column))
+                     (setq p (point))))
+         (when (or (not (bolp))
+                   (and p (goto-char p)))
+           (setq p nil)
+           (forward-char 1)
+           (insert "\n")
+           (when (looking-at "[\t ]+")
+             (delete-region (point) (match-end 0)))
+           (insert " ")
+           (end-of-line)))))))
 
 ;;; Syntax tables and abbrev-expansion