bug#17577: 24.3.91; Error during redisplay prevent quitting.

[Thierry Volpiatto <thierry.volpiatto@gmail.com>]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> This doesn't come from pre-redisplay-function but from updating the
> mode-line, and I can't remember modifying this code.  And it seems that
> this code has never run with inhibit-quit.  At least, that's what
>
> (setq header-line-format '("" (:eval (format "inhibit-quit=%S" inhibit-quit))))
>
> tells me in Emacs-23.4.  Actually, I see that inhibit-quit is also nil
> while running jit-lock, which baffles me.  But indeed, if I add a slow
> font-lock rule and hit C-g while it's processing that rule, I get:
>
>    Error during redisplay: (quit)
>
> So I wonder why this is new.  My best explanation is that it's actually
> not new, but for some odd reason the timing has changed such that it
> happens more often now.

This one is indeed not new, the new thing is quit is involved here, and
it seems your patch fix the issue with redisplay and this one too, don't
know why though.

> Since pre-redisplay-function is new in 24.4, it's important we fix the
> bugs it introduces, so please remove this workaround from helm.el.

Done.

> The "when" check is redundant.

Indeed yes, a vestige of code using only car, thanks.

> Hmm... grepping around, "Emacs-lisp:" seems extremely unlikely, but
> maybe you meant "Emacs-Lisp:" which I guess could potentially come from
> the rarely used "menu in echo area" feature, i.e. "Emacs-Lisp" would
> come from the name of a keymap.  Why/how this happens, I don't know.

I don't know too, seems fixed now after updating emacs-24 branch, same,
don't know why.

> I installed the patch below into the `emacs-24' branch.  Could you try
> it and see if it solves the problem for you?

Yes it is fixed, many thanks for this.

-- 
Thierry
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