rmail-cease-edit fixes related to "^From " escaping

* mail/rmail.el (rmail-mime-decoded): New permanent local.
(rmail-show-message-1): Set rmail-mime-decoded when appropriate.
* mail/rmailedit.el (rmail-cease-edit): Respect rmail-mbox-format
and rmail-mime-decoded.

Fixes: debbugs:9841

3 files changed, 30 insertions, 4 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 940dc62fedf..36fc8eea448 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,5 +1,10 @@
 2012-12-07  Glenn Morris  <rgm@gnu.org>
 
+        * mail/rmail.el (rmail-mime-decoded): New permanent local.
+        (rmail-show-message-1): Set rmail-mime-decoded when appropriate.
+        * mail/rmailedit.el (rmail-cease-edit): Respect rmail-mbox-format
+        and rmail-mime-decoded.  (Bug#9841)
+
         * mail/unrmail.el (unrmail-mbox-format): New option.  (Bug#6574)
         (batch-unrmail, unrmail): Doc fixes.
         (unrmail): Respect unrmail-mbox-format.
diff --git a/lisp/mail/rmail.el b/lisp/mail/rmail.el
index 446ea4de0f3..c0fb7d1c5bd 100644
--- a/lisp/mail/rmail.el
+++ b/lisp/mail/rmail.el
@@ -100,6 +100,10 @@ its character representation and its display representation.")
   "The current header display style choice, one of
 'normal (selected headers) or 'full (all headers).")
 
+(defvar rmail-mime-decoded nil
+  "Non-nil if message has been processed by `rmail-show-mime-function'.")
+(put 'rmail-mime-decoded 'permanent-local t) ; for rmail-edit
+
 (defgroup rmail nil
   "Mail reader for Emacs."
   :group 'mail)
@@ -2768,6 +2772,7 @@ The current mail message becomes the message displayed."
                  (re-search-forward "mime-version: 1.0" nil t))
             (let ((rmail-buffer mbox-buf)
                   (rmail-view-buffer view-buf))
+              (set (make-local-variable 'rmail-mime-decoded) t)
               (funcall rmail-show-mime-function))
           (setq body-start (search-forward "\n\n" nil t))
           (narrow-to-region beg (point))
diff --git a/lisp/mail/rmailedit.el b/lisp/mail/rmailedit.el
index e4e066bd642..004eb2e3247 100644
--- a/lisp/mail/rmailedit.el
+++ b/lisp/mail/rmailedit.el
@@ -167,10 +167,25 @@ This function runs the hooks `text-mode-hook' and `rmail-edit-mode-hook'.
   (if (or rmail-old-mime-state
           (not rmail-old-pruned))
       (forward-line 1))
-  (while (re-search-forward "^>*From " nil t)
-    (beginning-of-line)
-    (insert ">")
-    (forward-line))
+  ;; When editing a non-MIME message, rmail-show-message-1 has unescaped
+  ;; ^>*From lines according to rmail-mbox-format.  We are editing
+  ;; the message as it was displayed, and need to put the escapes when done.
+  ;; When editing a MIME message, we are editing the "raw" message.
+  ;; ^>*From lines have not been escaped, but we still need to ensure
+  ;; a "^From " line is escaped so as not to break later parsing (?).
+  ;; With ^>+From lines, we have no way of knowing whether the person
+  ;; doing the editing escaped them or not, so it seems best to leave
+  ;; them alone.  (This all assumes you are using rmailmm rather than
+  ;; something else that behaves differently.)
+  (let ((fromline (if (or (eq 'mboxo rmail-mbox-format)
+                          rmail-mime-decoded)
+                      "^From "
+                    "^>*From "))
+        case-fold-search)
+    (while (re-search-forward fromline nil t)
+      (beginning-of-line)
+      (insert ">")
+      (forward-line)))
   ;; Make sure buffer ends with a blank line so as not to run this
   ;; message together with the following one.
   (goto-char (point-max))
@@ -201,6 +216,7 @@ This function runs the hooks `text-mode-hook' and `rmail-edit-mode-hook'.
       (setq buffer-undo-list t)
       (rmail-variables))
     ;; If text has really changed, mark message as edited.
+    ;; FIXME we should do the comparison before escaping From lines.
     (unless (and (= (length old) (- (point-max) (point-min)))
                  (string= old (buffer-substring (point-min) (point-max))))
       (setq old nil)