Re: How the long-lines "optimisation" breaks font locking.

[Eli Zaretskii <eliz@gnu.org>]

> Date: Thu, 4 Aug 2022 14:44:05 +0000
> Cc: larsi@gnus.org, emacs-devel@gnu.org, gregory@heytings.org
> From: Alan Mackenzie <acm@muc.de>
> 
> > > Well I tried CC Mode with a 1,000,000 character raw string.  It was
> > > indeed a bit sluggish but "hang indefinitely" is an exaggeration.
> 
> > Try it with a 20MB raw string, then.  And, for good measure, in an
> > unoptimized build.  These are the cases we are trying to make
> > workable.
> 
> No matter what criterion one deems "workable", there will be some size of
> buffer, or line, which renders Emacs "unworkable".

Not with narrowing, no.  Because the size of the narrowed region is
independent of the buffer size.  That's the main idea of these
changes, and that's why the idea is IMO a good one.

> > > Doing these things in the current master branch indeed appeared to be
> > > fast, but at one point an error in an after-change-function caused
> > > after-change-functions to get set to nil, crashing CC Mode.
> 
> > If you can show a recipe for this problem, we will fix it.  This code
> > is WIP, so some problems definitely remain and should be reported and
> > fixed.
> 
> I'll see if I can recreate it.

TIA.