bug#56682: locked narrowing

[Gregory Heytings]

> > Stefan's proposed approach looks promising, however.
>
> I explained why in my other messages why it sounds too complicated.

Yet it's AFAICS the only possible approach that was proposed so far.

> > That fix is wrong, sorry.  Now the detection loop is triggered each 
> > time the user changes the narrowing, in the vast majority of cases for 
> > no good reason.
>
> The same will happen when the user types several characters.  Which 
> happens more frequently than changes of narrowing, in most use patterns.

The change is wrong nonetheless.  It's a local fix to circumvent an 
example scenario I gave, which was just that: an example.  Many other 
scenarios remain.

> And once again, you simply _cannot_ access buffer text beyond BEGV..ZV 
> safely.  It's a ticking time bomb if you do.

I already said I agree with that.  I only said (before Stefan proposed a 
potential solution) that I did not see a better way to handle that 
situation.

> I'm sorry, but I cannot afford this endless argument; I'm swamped with 
> too many tasks that no one else except myself seems to be doing, and 
> this argument already took an inordinate amount of my time and energy.
>
> Please install your UNCHANGED_MODIFIED patch, and I will get to 
> improving the scalability of the scanning loop when I have time. Please 
> don't install any other changes in this regard except that one patch.

Are you serious???  I mean, I've been spending an inordinate amount of my 
time to fix that long line problem, I think I now have a certain expertise 
in that area, I'm trying to find a way to improve these heuristics, you 
dismiss what I'm telling you, and now you tell me that you have too many 
tasks on your plate and that you nonetheless want to improve these 
heuristics yourself and that I should stop working on this???