Re: Possibly defaulting native-compile-target-directory to XDG_CACHE_HOME/...

[Eli Zaretskii]

> From: Rob Browning <rlb@defaultvalue.org>
> Cc: emacs-devel@gnu.org
> Date: Sat, 17 Dec 2022 14:37:18 -0600
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > I don't see how this follows from what I said.  There should be a
> > writable directory, but it doesn't have to be under HOME.  You can
> > change the value of native-comp-eln-load-path to have there any
> > directories you like.  We've been through this during the previous
> > discussion, I believe.
> 
> I may not have understood where all of that ended up.
> 
> Given that there's no way to establish the location via an envt var.
> Are you saying that anyone who needs to run emacs with an unwritable
> home would need to add one or more command line arguments to every
> invocation (i.e. we'd need to do that across all of the relevant debian
> testing scripts, etc., some of which may be embedded in upstream
> frameworks -- I guess we might also just shadow emacs in the path with a
> wrapper script...)?

No.  I'm saying that these users should add a one-liner to their init
file.

> ...and if any of the relevant command line settings don't happen early
> enough, then that'd be considered a bug that we'd want to report and see
> about fixing?

I don't understand this part.  What do you mean by "happen early
enough"?

> Oh, and I can finally reproduce that buttercup crash with an upstream
> tree.  This should do it:
> 
>   # Build and install emacs-28.2 as root or "user1"
> 
>   # As "user2" (not root or user1)
>   git clone https://github.com/jorgenschaefer/emacs-buttercup.git
>   cd emacs-buttercup
>   export HOME=/nope
>   rm -f *.elc
>   emacs -Q -batch -L . -f batch-byte-compile buttercup.el buttercup-compat.el
>   emacs -Q -batch -L . -l buttercup -f buttercup-run-discover
> 
> The key appears to be that the install must be as some other user.

Is there something in emacs-buttercup that makes it necessary for
reproducing this?  Or would any byte-compiled file do?

Anyway, what happens if you try this with Emacs 29?  Emacs 28 is in
the past for us: there will be no more releases from the emacs-28
branch.  And on Emacs 29 we made some changes which I think should
prevent these problems.