Re: Popup when buffer file is changed on disk

[Luc Teirlinck <teirllm@dms.auburn.edu>]

If you are going to do this, at least make it an option that is by
default off.

The rationale behind checking for and warning about files that have
changed on disk _after a focus change_ is apparently the assumption
that most files change on disk because you edited them with another
editor.  Many people only use one editor, Emacs.  For them that
assumption is completely wrong.

Files can change on disk for several reasons, including:

1.  Because you edited them with another editor.

2.  Because some process is writing to them.

3.  Because another person is editing them.

4.  Because you changed them from within Emacs in some way that
    bypassed the buffer.  (To be avoided, but can inadvertently happen.)

(2), (3) and (4) are unrelated to focus changes.  They can happen any
time.  For people that only edit files using Emacs, (1) never happens.

If processes are writing to files visited in buffers, files are going
to change on disk all the time.  I would be reminded about that on
just about every focus change, even though I know that autorevert is
going to revert them within 5 seconds or less.  This is senseless.

Clearly, the best way to deal with all ways that a file can change on
disk is a combination of mode line and Buffer Menu.  (And still this
would only be needed if for some reason you do not want to use
autorevert or if you are editing files that could change on disk.)
The mode line and Buffer Menu features would not be very difficult to
implement.  But we are in a feature freeze, so I believe it can wait
till Emacs 22.

Sincerely,

Luc.