Re: master 19a3b499f84: ; * lisp/loadup.el: Don't prohibit advice when ls-lisp is loaded.

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: Po Lu <luangruo@yahoo.com>
> Date: Tue, 05 Dec 2023 18:20:19 -0500
> 
> > +(unless (featurep 'ls-lisp)
> > +  ;; Actively disallow advised functions during preload since:
> > +  ;; - advices in Emacs's core are generally considered bad style;
> > +  ;; - `Snarf-documentation' looses docstrings of primitives advised
> > +  ;;   during preload (bug#66032#20).
> > +  ;;
> > +  ;; Don't verify this under MS-Windows and Android, both systems that
> > +  ;; load ls-lisp, which advises insert-directory.
> 
> How 'bout we fix this as well?
> 
> IOW, merge `insert-directory` and `ls-lisp--insert-directory`
> by allowing `insert-directory-program` to be nil
> (as a replacement for the `ls-lisp-use-insert-directory-program`
> boolean) in which case we use the ls-lisp code?

So if some Lisp program out there sets insert-directory-program to a
non-nil value (probably intending to affect only Posix systems), Emacs
on MS-Windows will suddenly start using it instead of ls-lisp?

In general, IMO it's too late to make changes in this arrangement that
would require users to switch to customizing a different user option.