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

[Dmitry Gutov]

On 06.08.2022 08:36, Eli Zaretskii wrote:
> > Date: Fri, 5 Aug 2022 22:50:07 +0300
> > Cc: acm@muc.de, larsi@gnus.org, emacs-devel@gnu.org, gregory@heytings.org
> > From: Dmitry Gutov <dgutov@yandex.ru>
> >
> > On 05.08.2022 18:30, Eli Zaretskii wrote:
> > > > The slow part I'm referring to is not in font-lock's code, nor in CC
> > > > Mode's font-lock rules. So it can be "fixed" independently.
> > > Then where is it?
> >
> > Probably somewhere in the recent xdisp.c changes.
>
> Very unlikely.  The recent changes in xdisp.c could not have possibly
> slowed down the code there.

No, no. They fixed it.

That's why the advice to set long-line-threshold to nil (if one wants 
correct fontification) is not so great: it brings those issues back.