Re: Making Emacs Lisp easier to debug

[Ihor Radchenko]

Eli Zaretskii <eliz@gnu.org> writes:

>> (ii) Edebugging font locking code.  It would be nice to be able to debug
>> font locking code which is being called from redisplay, as well as other
>> hooks which are also called from redisplay.  At the moment this isn't
>> possible.  To make it possible would require redisplay to become
>> reentrant, so that a frame or window in the inner redisplay call 
>> could be where debugging of the outer redisplay call happens.  I don't
>> know how practicable it would be to enhance redisplay for this (it is
>> certainly possible).  Has anybody ever looked into this before?
>
> Yes, see jit-lock-debug-mode.  (It's described in the ELisp manual.)

Also, I found built-in M-x font-lock-debug-fontify helpful.
And third-party package https://github.com/Lindydancer/font-lock-studio
Finally, `backtrace-on-redisplay-error' is useful.

-- 
Ihor Radchenko // yantar92,
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