reverting non-file buffers in earlier Emacs versions.

reverting non-file buffers in earlier Emacs versions.

[Luc Teirlinck]

I suggest the following documentation changes to autorevert.el and
emacs-xtra.texi.  The reason for the changes is that in Emacs versions
21.3 and earlier, autoreverting of non-file buffers seems to cause
serious problems.  In Emacs-21.3, Dired buffers autorevert every five
seconds, print a message every five seconds, constantly overshouting
what I am trying to type in the echo area, and point in a Dired buffer
shoots back to the beginning of the buffer every five seconds.

So I want to give the reader at least some indication that
autoreverting of non-file buffers worked quite differently in earlier
Emacs versions.

I will install if there are no objections.

===File ~/autorevert-diff===================================
*** autorevert.el	29 Dec 2004 21:08:55 -0600	1.42
--- autorevert.el	23 Jan 2005 21:57:14 -0600	
***************
*** 208,213 ****
--- 208,216 ----
  of files.  You may still sometimes want to revert them manually.
  
  Use this option with care since it could lead to excessive auto-reverts.
+ This is especially true in versions 21.3 and earlier of Emacs,
+ but should be much less of a problem in 21.4 or later.
+ 
  For more information, see Info node `(emacs-xtra)Autorevert'."
    :group 'auto-revert
    :type 'boolean
============================================================

===File ~/emacs-xtra-diff===================================
*** emacs-xtra.texi	18 Jul 2004 11:01:23 -0500	1.7
--- emacs-xtra.texi	23 Jan 2005 21:50:29 -0600	
***************
*** 10,16 ****
  @copying
  This manual describes specialized features of Emacs.
  
! Copyright (C) 2004
  Free Software Foundation, Inc.
  
  @quotation
--- 10,16 ----
  @copying
  This manual describes specialized features of Emacs.
  
! Copyright (C) 2004, 2005
  Free Software Foundation, Inc.
  
  @quotation
***************
*** 96,101 ****
--- 96,106 ----
  implemented, that is, for the types of buffers listed in the menu
  below.
  
+ This chapter describes the behavior in Emacs versions 21.4 or later.
+ In earlier versions, auto-reverting of non-file buffers, while
+ possible, could cause several problems such as excessive reverts,
+ excessive noisiness, inappropriate point movement and the like.
+ 
  Like file buffers, non-file buffers should normally not revert while
  you are working on them, or while they contain information that might
  get lost after reverting.  Therefore, they do not revert if they are
============================================================

Re: reverting non-file buffers in earlier Emacs versions.

[Eli Zaretskii]

> Date: Mon, 24 Jan 2005 19:26:04 -0600 (CST)
> From: Luc Teirlinck <teirllm@dms.auburn.edu>
> 
> I suggest the following documentation changes to autorevert.el and
> emacs-xtra.texi.  The reason for the changes is that in Emacs versions
> 21.3 and earlier, autoreverting of non-file buffers seems to cause
> serious problems.  In Emacs-21.3, Dired buffers autorevert every five
> seconds, print a message every five seconds, constantly overshouting
> what I am trying to type in the echo area, and point in a Dired buffer
> shoots back to the beginning of the buffer every five seconds.
> 
> So I want to give the reader at least some indication that
> autoreverting of non-file buffers worked quite differently in earlier
> Emacs versions.
> 
> I will install if there are no objections.

Objection, your honor! ;-)

Seriously: I don't think these changes should be installed.  What they
try to do is change history: you are adding information that should
have been there in previous Emacs versions, because the problems you
describe do not exist anymore in the current version.  Since the
updated files will be distributed with the new version of Emacs, what
purpose will the additional text serve?  How will it help users of
Emacs 21.4 to know that in older versions Auto Revert worked worse
than it does now?

This information should be in etc/NEWS -- and AFAICS it is already
there.  So I don't think we should make these changes.

Re: reverting non-file buffers in earlier Emacs versions.

[Richard Stallman]

Mentioning this in emacs-xtra.texi could be useful if it is done
in a slightly different way:

    + This chapter describes the behavior in Emacs versions 21.4 or later.

It is redundant to say so here.  Everything in this manual that comes
with Emacs 21.4 will describe something about Emacs version 21.4.

    + In earlier versions, auto-reverting of non-file buffers, while
    + possible, could cause several problems such as excessive reverts,
    + excessive noisiness, inappropriate point movement and the like.

It is useful to say that.  "In earlier versions" could be replaced
with "In Emacs versions before 21.4".

The change in autorevert.el is unnecessary.  Anyone who sees that doc
string will see it in Emacs 21.4 only.