bug#4587: bug#4597: Antwort: Re: bug#4587: 23.1; sort-lines and sort-fields always set buffer modified

[Eli Zaretskii <eliz@gnu.org>]

> Resent-From: Lars Ingebrigtsen <larsi@gnus.org>
> Original-Sender: "Debbugs-submit" <debbugs-submit-bounces@debbugs.gnu.org>
> Resent-CC: bug-gnu-emacs@gnu.org
> Resent-Sender: help-debbugs@gnu.org
> Cc: 4587@debbugs.gnu.org, rm369@arcor.de, 4597@debbugs.gnu.org
> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Tue, 03 May 2022 21:24:09 +0200
> 
> Roland.Meier@continental-corporation.com writes:
> 
> > M-x sort-lines and M-x sort-fields always set the buffer modified 
> > status ("-" -> "*" in column 5 of the status line), even if the region 
> > was sorted and the command did not modify anything. 
> > An unmodified buffer should stay unmodified if nothing was changed. 
> 
> (I'm going through old bug reports that unfortunately weren't resolved
> at the time.)
> 
> I've now fixed this in Emacs 29.

This uses buffer-hash, which is only sensitive to changes in the byte
sequences of the buffer text.  AFAIU, it doesn't know about other
possible changes we perceive as "buffer changes", like changes in
faces, overlays, buffer-file-coding-system, etc.  Shouldn't this be
prominently documented in the macro's doc string?