Re: The unwarranted scrolling assumption

[Lennart Borgman]

On Fri, Jun 18, 2010 at 4:29 PM, Eli Zaretskii <address@hidden> wrote:
>>
>> This is the what I used to get the output I sent:
>>
>>   if (b->clip_changed)
>>     DebPrint (("+++reconsider: end_valid=%d, b=%d, ZV=%d, BEGV=%d",
>>                !NILP (w->window_end_valid),
>>                w->current_matrix->buffer == b,
>>                w->current_matrix->zv == BUF_ZV (b),
>>                w->current_matrix->begv == BUF_BEGV (b)));
>
> And what was the output?  I don't see it in this thread.


Sorry, I do not have it currently. If necessary I will recreate it,
but not until you have convinced me that my patch is wrong.


>> The problem is how clip_changed is handled by narrow_to_region etc.
>> That is what my patch is about.
>
> I think your patch is wrong.


Yes I know. But let us look into this. So far you have not convinced
me. Please try to.


> I think the current code handles the
> case you are trying to "fix" just fine.


It looks like you are totally missing the point of my patch.


> It tried to recenter for some
> reason, and I'm trying to find out what that reason was.  I'm guessing
> that the reason was the window_end_valid flag was nil.  If you confirm
> that, we could then start looking for why that flag was nil.  Reusing
> the current matrix when that flag is nil is unsafe.


Sure I will later if it is necessary. But this is not where we are now.


>> As I have said several times I think the problem is that clip_changed
>> is set by narrow_to_region etc. Please look into this first.
>
> I already did, and I think that code is correct.  Obviously,
> clip_changed needs to be set whenever the narrowing changes.


Ah, finally. Good.

And why do you think that?