bug#55451: 28.1.50; Executing (jit-lock-mode -1) does not disable jit-lock-mode

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: Eli Zaretskii <eliz@gnu.org>,  55451@debbugs.gnu.org
> Date: Wed, 18 May 2022 19:27:58 +0200
> 
> Ihor Radchenko <yantar92@gmail.com> writes:
> 
> > However, I am confused why it is impossible to follow +1/-1 convention.
> > Looking through jit-lock.el I do not see any place where any value other
> > than non-nil/nil is considered.
> 
> It would be incompatible -- all non-nil values switch jit-lock on
> presently, including -1.

Yes.  Moreover, it's hardly worth the hassle: who would switch off
jit-lock, except for debugging jit-lock?  Most people will never do,
which is very unlike every minor mode out there -- those are switched
on and off all the time.  It isn't an accident that we don't have the
"M-x jit-lock-mode" command.