bug#74627: .dir-locals.el warning messages are confusing

[Eli Zaretskii]

> From: Björn Lindqvist <bjourne@gmail.com>
> Date: Wed, 11 Dec 2024 09:18:33 +0100
> Cc: Stefan Monnier <monnier@iro.umontreal.ca>, 74627@debbugs.gnu.org
> 
> Den tors 5 dec. 2024 kl 10:38 skrev Eli Zaretskii <eliz@gnu.org>:
> 
> > > Warnings about potential security issues should be easy to understand,
> > > but the warnings produced by .dir-locals.el are not. When I open a
> > > file in the Emacs source code it shows:
> > >
> > >     The local variables list in /home/bjourne/p/emacs/
> > >     or .dir-locals.el contains values that may not be safe (*).
> > >
> > > Why does it say "or"?
> >
> > Because that function is called with a single flag argument which
> > could be set non-nil either due to unsafe file-local variables or due
> > to .dir-locals.el.
> 
> So there are multiple sources of unsafe variables, but the function
> responsible for formulating the error message doesn't know what the
> source is?

Yes, that's my reading of the code.

> Regardless of whether my guess is correct, the text should
> not refer to the local variables in "/home/bjourne/p/emacs/" because
> there can be no unsafe variables in directories (only files).

Well, we consider variables in .dir-locals.el as belonging to the
directory in which it lives.

> > > What does the asterisk (*) mean?
> >
> > It means the variables marked with the asterisk in the list of
> > below this text could be unsafe.
> 
> Aha. Emacs lists both safe and unsafe variables. Why does it list the
> safe ones? The warning would be much clearer if the safe variables
> were omitted since they don't matter. That would make it clear what
> variables "!" and "i" choices apply or mark as safe/ignored.

I can only guess: showing all of them lets you see the problematic one
in context.