bug#9296: 24.0.50; next-line/prev-line on lines with images

[Eli Zaretskii <eliz@gnu.org>]

> From: Lars Magne Ingebrigtsen <larsi@gnus.org>
> Cc: 9296@debbugs.gnu.org
> Date: Sun, 14 Aug 2011 21:37:41 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> I haven't seen this behaviour before, I think, and it's odd that I
> >> haven't noticed, since I'm using images heavily in several modes...
> >
> > Which behavior are you talking about?  The one that still exists with
> > the current trunk, or the one I fixed today?
> 
> The behaviour after the last fix.  It's not the same as the
> (non-perfect) Emacs 23 behaviour on long `truncate-line' lines.

I need a reproducible test case.  The one you sent today misbehaves
with Emacs 23 and the current trunk alike.  E.g., after you evaluate
the expression and are in the buffer with the images, go to the end
(M->), then try C-p several times, followed by C-n several times, and
again several C-p's.  I see, in both Emacs 23 and 24, that the cursor
starts on the images, but after a few C-p's and C-n's jumps to some
column greater than zero, then jumps yet again, etc.  All this with
the default 80-column frames.

Don't you see this in Emacs 23.3?