Re: font-lock latency

[Simon Josefsson]

Simon Josefsson <jas@extundo.com> writes:

> Richard Stallman <rms@gnu.org> writes:
>
>>     Doesn't help, the line is still incorrectly highlighted.  I even tried
>>     pressing M-g M-g on every line of the buffer, but it was still wrong.
>>     C-l doesn't help either.  Only way to get it right is to wait a few
>>     (3?) seconds.
>>
>> If some code that runs after 3 seconds gets it right,
>> the first thing to do is find that code,
>> and see how it gets the right results.
>
> The code is `jit-lock-stealth-fontify'.  I now realized that if I set
> `jit-lock-stealth-time' to 0 _before_ I enable font-lock-mode, it does
> what I want -- that is, update the buffer immediately.
>
> jit-lock.el looks like voodoo to me, so I'm not going to try to find
> out what caused the original problem.  Unless it has negative
> consequences, I think the default of `jit-lock-stealth-time' should be
> changed to 0 so that this bug isn't visible.  Assuming noone finds the
> original cause of the problem, that is.

I revoke that suggestion, setting `jit-lock-stealth-fontify' to 0
seems to trigger other problems.  After editing a file for a while
(difficult to reproduce) I get a backtrace like the below when
pressing any key.

I am now running with j-l-s-f set to 1 even though it annoys me, and I
haven't seen the backtrace yet.

Debugger entered--Lisp error: (args-out-of-range 6 4)
  font-lock-fontify-keywords-region(35308 35328 nil)
  font-lock-default-fontify-region(35308 35317 nil)
  font-lock-fontify-region(35308 35317)
  run-hook-with-args(font-lock-fontify-region 35308 35317)
  jit-lock-fontify-now(35308 35808)
  jit-lock-function(35308)