Re: suggestion: reverting/notifying of files that no longer exist

[Juri Linkov]

Karl Chen <address@hidden> writes:
>> One place where the warning could be added is `basic-save-buffer'.
>
> That would be good; I think it'd be even better however if it
> notified you the second you start editing.  Because otherwise if
> you work on it for 20 minutes before saving, you've already
> "forked."

Notifying at the moment you start editing would be good too.
Perhaps instead of creating a new function, that could be done
in the existing function `ask-user-about-supersession-threat'
which is already used for a similar purpose, and which could be
called from `prepare_to_modify_buffer' when a previously saved
file was deleted or renamed.

Index: src/insdel.c
===================================================================
RCS file: /cvsroot/emacs/emacs/src/insdel.c,v
retrieving revision 1.178
diff -u -r1.178 insdel.c
--- src/insdel.c        22 May 2004 22:15:37 -0000      1.178
+++ src/insdel.c        14 Jul 2004 14:05:07 -0000
@@ -1931,7 +1931,14 @@
       /* Make binding buffer-file-name to nil effective.  */
       && !NILP (current_buffer->filename)
       && SAVE_MODIFF >= MODIFF)
-    lock_file (current_buffer->file_truename);
+    {
+      lock_file (current_buffer->file_truename);
+      if (NILP (Fverify_visited_file_modtime (Fcurrent_buffer ()))
+          && current_buffer->save_length > 0
+          && NILP (Ffile_exists_p (current_buffer->filename)))
+        call1 (intern ("ask-user-about-supersession-threat"),
+               current_buffer->filename);
+    }
 #else
   /* At least warn if this file has changed on disk since it was visited.  */
   if (!NILP (current_buffer->filename)

Index: lisp/userlock.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/userlock.el,v
retrieving revision 1.14
diff -u -r1.14 userlock.el
--- lisp/userlock.el    1 Sep 2003 15:45:17 -0000       1.14
+++ lisp/userlock.el    14 Jul 2004 14:05:34 -0000
@@ -112,8 +112,10 @@
   (save-window-excursion
     (let (answer)
       (while (null answer)
-       (message "%s changed on disk; really edit the buffer? (y, n, r or C-h) "
-                (file-name-nondirectory fn))
+       (message "%s %s on disk; really edit the buffer? (y, n, r or C-h) "
+                (file-name-nondirectory fn)
+                 (if (file-exists-p buffer-file-name)
+                     "changed" "renamed or deleted"))
        (let ((tem (downcase (let ((cursor-in-echo-area t))
                               (read-char-exclusive)))))
          (setq answer
@@ -137,8 +139,11 @@
                 (signal 'file-supersession
                         (list "File reverted" fn)))
                ((eq answer 'yield)
-                (signal 'file-supersession
-                        (list "File changed on disk" fn))))))
+                 (if (file-exists-p buffer-file-name)
+                     (signal 'file-supersession
+                             (list "File changed on disk" fn))
+                   (signal 'file-supersession
+                           (list "File renamed or deleted on disk" fn)))))))
       (message
         "File on disk now will become a backup file if you save these 
changes.")
       (setq buffer-backed-up nil))))

-- 
Juri Linkov
http://www.jurta.org/emacs/