bug#48331: Emacs' describe-package doesn't work for packages managed by guix

[Leo Prikler <leo.prikler@student.tugraz.at>]

Am Dienstag, den 11.05.2021, 18:57 +0300 schrieb Andrew Tropin:
> Patched emacs-build-system to place packages under elpa/NAME-VERSION
> subdirectory and removed "-pkg\\.el$" from %default-exclude.
I don't know whether that's a good idea.  The elpa/ part I already
dislike, and the "-pkg\\.el$" exclude might have existed for a reason
(I don't know which, put perhaps byte compilation).

> > I have now published emacs-dpd [2], which does exactly that.  To
> > use it
> > for your Guix Emacs packages, execute
> >   (dpd (list "$GUIX_PROFILE/share/emacs/site-lisp" ...))
> > replacing "$GUIX_PROFILE" with the actual profile, after `package-
> > initialize' has run with `dpd-fuzzy-recognize' in `dpd-recognize-
> > hook'.
> > I might write a more detailed README later.
> 
> Most of the packages already have -pkg.el in sources, but yep, pretty
> cool utility, also thought about implementing something like that
> yesterday, but luckily I didn't and now I do not need to do it,
> because
> now I'm aware of already-existing implementations!)
I know people take package.el for granted nowadays, but alternative
package managers for Emacs have their uses.  This is not just a Guix
thing :)

> > Neither packed nor dpd are currently packaged in Guix.  packed can
> > easily be imported from melpa-stable, but for dpd you'd have to
> > write
> > your own guix.scm.  I might do that at some point as well.
> > We already had modifications in emacs-build-system recently, so if
> > you
> > want to argue, that all Emacs packages should have that <package>-
> > pkg.el to work with package.el out of the box, I would ask you to
> > wait,
> > so as to not cause an "Emacs world" rebuild again after only ten
> > days.
> > I also don't know whether Guix has the same information as
> > package.el
> > at build time, but that might change with time as
> > well.  Particularly,
> > there will hopefully be a move towards supplying name and version
> > at
> > build, which would give us the most important information.
> 
> Very cool, I didn't have the latest changes on my local checkout and
> didn't
> see your commits, but now I see, it is exactly what I needed.
> 
> The only side note: it should be site-lisp/elpa/NAME-VERSION (right
> now
> it is site-lisp/NAME-VERSION).  Also, on line 137 elpa-directory
> function can be used.
I don't think we want to fake elpa that hard.  Two iterations ago it
was .guix.d and people didn't really like it.  My subdirs.el patch is
also stretching it.  So I really don't want to add another subdirectory
layer to it.
If elpa can't deal with that, we'll have to code around it in Elisp.

> When you will be updating the path, please remove -pkg.el from
> %default-exclude.
I've CC'd Maxim, perhaps they know more about %default-exclude.

Regards,
Leo