Re: problem with font lock

["Jose A. Ortega Ruiz" <jao@gnu.org>]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: "Jose A. Ortega Ruiz" <jao@gnu.org>
>> Date: Fri, 15 Jan 2010 13:14:09 +0100
>> 
>> i'm experiencing an intermittent problem with font lock that i don't
>> know how to debug (this is emacs 23.1.91 packaged for debian). every now
>> and then, font lock just stops working in most (but not all) of the
>> buffers: the extant colors remain, but new text is not coloured at all
>> (e.g., if i comment a line out, the line's text retains its initial
>> faces instead of switching to the comment face). as i said, i haven't
>> found a way to reproduce this behaviour deterministically, and when it
>> starts happening i don't see any error message around. so my question
>> is: what would you recommend to look at when i enter this state, so that
>> i can submit a useful bug report?
>
> Did you customize font-lock or jit-lock in any way?

I'm using customize themes that include many, many font lock faces;
other than that no.

> Does this happen in "emacs -Q"?

I don't know. It only happens after periods of days using emacs, and i
cannot afford that long without my customizations and other packages.

> If you type "M-x font-lock-fontify-buffer RET", after e.g., commenting
> a line, does the fontification catch up with the changes?

Yes, it does.

> Re-fontification when the buffer is modified or scrolled is done by
> jit-lock.el, and it generally runs off Emacs timers.  So anything that
> prevents times from running would have the effect that you seem to
> observe.

Sounds reasonable, specially since font-lock-fontify-buffer still works.
For now, i'll apply Stephan's advice and try to see if i reach the
condition with font-lock-support-mode disabled.

Thanks!

jao
-- 
There are two ways to write error-free programs; only the third one
works.
  - Alan Perlis, Epigrams in Programing