Subject: Re: bug#75328: 31.0.50; use-package cannot override a built in package

From: Eli Zaretskii <[email-masked]>
Date: Sun, 05 Jan 2025 08:36:46 +0200

> From: Philip Kaludercic <[email-masked]>
> Cc: "Mark A. Hershberger" <[email-masked]>,  [email-masked]
> Date: Sat, 04 Jan 2025 21:57:18 +0000
> 
> Eli Zaretskii <[email-masked]> writes:
> 
> >> The following does not check out the transient repository into
> >> ~/.emacs.d/elpa/:
> >> 
> >>     rm -rf ~/.emacs.d &&
> >>     echo '(setq package-install-upgrade-built-in t)
> >>     (use-package transient :vc (:url "https://github.com/magit/transient" :rev :newest) :ensure t)' > ~/.emacs &&
> >>     ~/bin/emacs
> >
> > Philip, shouldn't package-install-upgrade-built-in allow upgrading a
> > built-in package via use--package's :vc keyword?
> 
> Built-in packages are not supported by package-vc right now, as
> emacs.git is not a emacs package the way ELPA intends it.  There is also
> the annoyance that without custom code (which would be doable if we had
> to) we would have a separate checkout of emacs.git for every built-in
> package that one wishes to clone that way.  This would be a lot easier
> if Git would support subtree or single-file checkouts...

So we should convert this bug into a feature-request, and meanwhile
document this restriction in the use-package manual?