bug#75017: 31.0.50; Untrusted user lisp files

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: john muhl <jm@pub.pink>,  75017@debbugs.gnu.org,  Eli Zaretskii
>  <eliz@gnu.org>,  Andrea Corallo <acorallo@gnu.org>
> Date: Sat, 21 Dec 2024 22:16:05 -0500
> 
> > Maybe we should install something like the below?
> 
> Fine by me, but I think this should be added via a new
> `trusted-content-function(s)` and added buffer-locally only in
> elisp-mode buffers.

Sorry, but this is slippery slope.  For starters, no one said that
site-run-file is installed by a sysadmin -- that is only so on certain
systems.  For example, MS-Windows is generally not in that category.

More generally, if we go this way, i.e. every complaint by some user
about a file that _could_ be trusted, or even is trusted on a group of
systems, causes us to add more and more files and directories to the
trusted list, there will be no end to this, and, significantly, Emacs
30 will never be released.

So from where I stand, what we have now on the latest emacs-30 branch
is as good and as far as it gets, at least for Emacs 30.  My
suggestion to anyone who wants additional files/directories to vet to
please use the existing facilities to add them to the trusted list.
This way, we collect experience and data points regarding which
files/directories and under what conditions should be trusted, and can
improve what we have now in the future.  At that future time we should
probably ask users to name the files and directories they needed to
add to the trusted list, and take it from there, making changes which
will take that into account.

If you still insist on installing such changes at this time, please do
that on master.  My preference is to wait with this until we have
enough experience with what we have, which means not before Emacs 30.1
is released and a couple of months go by.  But if people insist on
installing now on master, I won't object.

Thanks.