Subject: Re: bug#44983: Truncate long lines of grep output

From: Lars Ingebrigtsen <[email-masked]>
Date: Sat, 30 Apr 2022 13:02:59 +0200

Eli Zaretskii <[email-masked]> writes:

> We are not.  The display engine will never call jit-lock on a region
> that starts in invisible text.  But a region that starts in visible
> text can end in invisible text, and font-lock doesn't pay attention to
> invisibility spec, AFAIR, it just looks at the buffer text
> disregarding everything else.

Yes, that's correct, I think.  But shouldn't it be smarter here?  That
is, the display engine does know that all the text it inserted was
invisible, so calling jit-lock again (with the same parameters as
previous time) is futile.

However, this is probably not something many modes do, so putting more
effort into optimising this is probably not worth it.

> For me, the more important question is: why the problem didn't
> disappear when you turned off font-lock-mode in the offending buffer.
> And I think I know why: you need to turn off jit-lock-mode as well.

Probably.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no