Re: The unwarranted scrolling assumption

[Eli Zaretskii]

> From: Lennart Borgman <address@hidden>
> Date: Fri, 18 Jun 2010 15:30:37 +0200
> Cc: address@hidden
> 
> >> It is !NILP (w->window_end_valid).
> >
> > ??? How can this be?  The code says:
> 
> A misunderstanding, sorry. I meant that in this case that line/code
> gave the value 0.
> 
> >  if (b->clip_changed
> >           && !NILP (w->window_end_valid)
> >           && w->current_matrix->buffer == b
> >           && w->current_matrix->zv == BUF_ZV (b)
> >           && w->current_matrix->begv == BUF_BEGV (b))
> >    b->clip_changed = 0;

So what is the value of w->window_end_valid when you enter
reconsider_clip_changes?  Is it nil?

> So far there are two (mabye three) distinct bugs I have seen:
> 
> 1) The handling of clip_changed, which I have sent a patch for.

I explained in another message why I think your patch is wrong.

The clip_changed flag should be reset to zero in order to enable the
scrolling optimization.  This is done by reconsider_clip_changes.  So
I think we should focus on understanding why it does not, in your
case.

> 2) The problems I described with visual-line-mode around line 702 in window.c.

That's an entirely different problem.  Let's handle this one problem
at a time.