Re: Fontification error backtrace [Was: Why is it so difficult to get a Lisp backtrace?]

[Eli Zaretskii <eliz@gnu.org>]

> From: Juri Linkov <juri@linkov.net>
> Cc: Stefan Monnier <monnier@iro.umontreal.ca>,  acm@muc.de,  larsi@gnus.org,
>  emacs-devel@gnu.org
> Date: Fri, 01 Jul 2022 18:34:01 +0300
> 
> >> BTW, in order to debug fontification errors, we also have
> >> `jit-locak-debug-mode` which postpones the jit/font-lock execution from
> >> within redisplay to "just a bit later" such that it can use the
> >> debugger.  IIRC it still has some rough edges in some cases, but in
> >> theory it should be possible to make this work such that you can (for
> >> example) Edebug `font-lock.el` itself.
> >
> > It would be nice to have this documented in the ELisp manual.  I can
> > easily add the jit-lock-debug-mode variable there, but from what you
> > write, there seems to be more wisdom to go with its usage.
> 
> Also would be nice to introduce a "log level" with possible values
> Fatal, Error, Warn, Info, Debug, Trace.  Then depending on the
> customized value decide whether print the complete backtrace to
> the *Messages* buffer, or only the error message, or nothing at all.

I don't necessarily object, but I'm asking myself who'd want less than
the complete information.  And I don't find any good answer; it seems
to me that whenever one gets the less detailed report, one will
immediately want the most detailed one.