bug#13780: 24.2; Making find-file-hook customizable seems to cause troublle

[Eli Zaretskii]

> From: Stefan Kangas <stefan@marxist.se>
> Date: Wed, 28 Oct 2020 01:52:42 -0700
> Cc: 13780@debbugs.gnu.org, Reuben Thomas <rrt@sc3d.org>
> 
> Stefan Monnier <monnier@iro.umontreal.ca> writes:
> 
> >>> So until Custom ...blabla... I think it's better to use defcustom for
> >>> hooks very sparingly, i.e. only for those hook we can reasonably
> >>> expect will only be modified by the user's customization.
> >> So do you think the existing customization ability for find-file-hook
> >> should be removed? Or at least some kind of warning attached?
> >
> > Yes,
> 
> So how about the attached?

That's a backward-incompatible change, isn't it?  Now a user who types
"M-x set-variable RET" will not be able to set this variable, it can
only be set via "M-:".  Do we have a serious enough reason for that?