bug#17777: [Emacs-diffs] emacs-24 r117241: Fix bug #17777 with keyboard macros and visual-order cursor movement.

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: 17777@debbugs.gnu.org
> Date: Sun, 15 Jun 2014 00:14:06 -0400
> 
> >> >    if (w->window_end_valid
> >> > +      && NILP (Vexecuting_kbd_macro)
> >> >        && !windows_or_buffers_changed
> >> >        && b
> >> >        && !b->clip_changed
> >> NILP (Vexecuting_kbd_macro) seems like a workaround.
> > It isn't.
> >> Why can't the glyph matrix be used in this case?
> > Because cursor position is not up-to-date in that case.
> >> I means which part of the glyph matrix is wrong in the OP's recipe
> >> (since this makes no change to the buffer)?
> > The cursor position.
> 
> But that can occur even without executing kbd macros, no?

Not sure what you mean by that.

> Wouldn't it be better to ignore the cursor position given in the glyph
> matrix and use (point) instead?

For the method that is based on up-to-date glyph matrices, I need to
know the glyph where the cursor is displayed.  The glyph coordinates
of that glyph are stored in the w->cursor structure, and updated by
redisplay.  The problem in the case in point was that redisplay is not
called as long as a macro is running.  So the coordinates from which
move-point-visually starts are incorrect.

I see no easy way of finding the cursor glyph coordinates by starting
from point; a (not so easy) way is the second method used by that
function.