bug#75352: 29.4; end-of-buffer is buggy after set-mark-command with some fonts

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sun, 5 Jan 2025 23:55:26 +0100
> From: Vincent Lefevre <vincent@vinc17.net>
> Cc: 75352@debbugs.gnu.org
> 
> > > The main problem is not a display problem, but the fact that the
> > > cursor (point) is not at the end of the buffer.
> > 
> > My point is that M-> doesn't guarantee that.
> 
> For the end user, this is very surprising (even with strange font
> settings, something that is not documented, AFAIK, and for which
> one gets no errors or warnings).

Supporting variable-height lines of text comes with rare situations
where this is necessary.

> > And yes, if the font changes, what was inside the viewport can become
> > outside, and that could cause Emacs move point.
> 
> IMHO, in such a case (when used with end-of-buffer), Emacs should scroll,
> keeping the point position.

It tries, but that is not always possible.

Anyway, to look into this further, I need a recipe that will reproduce
the problem with fonts I can install.  Until now, I was unable to see
anything like you describe, and I'm not on Debian to begin with.