Re: The unwarranted scrolling assumption

[Eli Zaretskii]

> From: Lennart Borgman <address@hidden>
> Date: Sat, 19 Jun 2010 22:38:24 +0200
> Cc: address@hidden, David De La Harpe Golden <address@hidden>
> 
> On Sat, Jun 19, 2010 at 10:30 PM, Juanma Barranquero <address@hidden> wrote:
> > On Sat, Jun 19, 2010 at 22:26, Lennart Borgman
> > <address@hidden> wrote:
> >
> >> This is expected. The original problem is still only addressed in my patch.
> >>
> >> And that is not applied.
> >
> > Then, help Eli understand why your patch is the right fix.
> 
> 
> I have done the best I can. I do not know what to do.
> 
> The basic assumption that clip_changed can be set in narrow_to_region
> etc and that redisplay later can decide when it can be reset is false.
> Redisplay does not have the necessary information since it does not
> know exactly why clip_changed was set to 1.
> 
> I have said that there is no reason to let narrow_to_region set
> clip_changed (even if it really seems intuitively right to do so). It
> is much easier to let redisplay do that instead in
> reconsider_clip_changes because then all needed information for the
> specific window is available.

Lennart, I need _evidence_, not ideas, assumptions, and theories.

We are not trying to rewrite the display code from scratch, we are
trying to fix a relatively minor problem in an otherwise working code.
The way to fix minor problems is not to find a totally different way
of doing something, but to find specific reason(s) why existing code
doesn't do what it was supposed to do.

IOW, it doesn't matter to me in how many different ways you can set
the clip_changed flag.  What I want to understand first and foremost
is why the _existing_ method fails.  Until I understand that, I cannot
reason about your suggested patch, and I therefore will not consider
it for inclusion in Emacs.

Now, I asked you repeatedly to give me values of variables inside
reconsider_clip_changes, which would explain why clip_changed is not
reset by it.  You didn't give those values to me, for some reason that
I cannot understand.  If you persist in your refusal to cooperate by
showing those values, and any others that I may need for this
investigation, I don't see any reason to continue talking to you in
this thread.