Re: <filename> changed on disk; really edit the buffer?

[martin rudalics]

> Yes.  After setting it to nil the problem is gone.
> I'm sorry for all the trouble.  I can't remember
> having this option set but it was changed.

You helped us to identify a bug.  Thanks.

We could, in auto_save_1, do something like

if (! NILP (Fstring_equal (current_buffer->filename,
                           current_buffer->auto_save_file_name)))
  Fclear_visited_file_modtime;

if the Fwrite_region succeeds, but I'm not sure of any implications of
this.  For example, current_buffer->save_length would not get set in
Fwrite_region.  Alternatively, we could try to simply save the buffer
which is the behavior described in the Elisp manual but this might be
more tricky.

> If this behavior is reasonable or if this setting
> is an end user setting is another question.  If this
> setting is set I wouldn't expect Emacs to complain
> about a changed file which was changed by Emacs.

Indeed.  Given the fact that apparently you are the first to report this
bug it seems that the option `auto-save-visited-file-name' is hardly
ever useful (at least nowadays).  The most attractive solution would be
to get rid of it.