bug#38812: 28.0.50; Custom: Problem with reverting some session's customizations

[Eli Zaretskii]

> From: Mauro Aranda <maurooaranda@gmail.com>
> Date: Tue, 31 Dec 2019 14:38:02 -0300
> Cc: 38812@debbugs.gnu.org
> 
> > My alternative patch is below.  WDYT?
> >
> > diff --git a/lisp/custom.el b/lisp/custom.el
> > index 26bdaae2c2..7ed85b22e8 100644
> > --- a/lisp/custom.el
> > +++ b/lisp/custom.el
> > @@ -886,7 +886,10 @@ custom-push-theme
> >   (put theme 'theme-settings
> >       (cons (list prop symbol theme value)
> >     (delq res theme-settings)))
> > - (setcar (cdr setting) value)))
> > +        ;; It's tempting to use setcar here, but that could
> > +        ;; inadvertently modify other properties in SYMBOL's proplist,
> > +        ;; if those just happen to share elements with the value of PROP.
> > +        (put symbol prop (cons (list theme value) (delq setting old)))))
> >       ;; Add a new setting:
> >       (t
> >        (when (custom--should-apply-setting theme)
> 
> Looks good, thank you.

Thanks, pushed.