Subject: bug#10652: font-lock very slow for C++

From: Alan Mackenzie <[email-masked]>
Date: Thu, 29 Mar 2012 22:00:26 +0000

Hello, Toon.

On Thu, Mar 29, 2012 at 09:46:03PM +0200, Toon Claes wrote:
> Hi Alan,

> About:
> (i) yes I've tried that, emacs -Q didn't make a difference

Worth knowing

> (ii) I am using emacs from git, commit 2ac37884107bd4e78bb… Should I
> get it from the bazaar repo?

I'm not familiar with the git repository.  If the revision is recent
(within the last week or two or three) it should be OK.  I just wanted to
check you weren't using a 6-month old version.

> (iii) I know font-lock has nothing to do with isearch. When I disable
> font-lock-mode for the buffer, isearch does not hang. So the issue
> isn't isearch. Sorry I created some confusion in previous mail.

OK.  What I suspect is that the isearch works fine, then the
fontification hangs before the screen can redisplay.  How long does it
hang for?  Any chance you could perhaps leave it hanging over lunchtime,
or perhaps even overnight to see if it might just be _very_ slow.

Could you perhaps try disabling font-lock, doing the isearch, then
enabling font-lock again.  Does it then still hang, or does it come up
OK?

Lastly, is there anything unusual about your test file.  Perhaps long
regions of text which contain no semicolons or maybe no braces?  Or maybe
hundreds of macro definitions one after the other, something like that?

> Toon

-- 
Alan Mackenzie (Nuremberg, Germany).