bug#68660: 29.2; ELPA: Wrong type argument w. multiple maintainers in package-menu-mode

[Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

> Hm, I'm starting to suspect this perceived "breakage" may in fact be
> intentional (i.e., a "schema evolution"), at least on the /devel
> endpoint, given it seems to be reflected in the disparity between
>
>   ;; /devel/archive-contents
>   (:maintainer ("Bob Weiner" . "rsw@gnu.org")
>                ("Mats Lidell" . "matsl@gnu.org"))
>
> and
>
>   ;; /packages/archive-contents
>   (:maintainer "Bob Weiner <rsw@gnu.org>, Mats Lidell"
>                . "matsl@gnu.org")

That just depends on when the package was built (i.e. before or after
`elpa.gnu.org`s Emacs was upgraded from Emacs-27 to Emacs-28).

> And likewise for ./foo-pkg.el in
>
>   ;; /devel/foo-42.0.tar
>   (define-package ... :maintainer
>     '(("Bob Weiner" . "rsw@gnu.org") ("Mats Lidell" . "matsl@gnu.org")))
>
> vs.
>
>   ;; /packages/foo-42.0.tar
>   (define-package ... :maintainer
>     '("Bob Weiner <rsw@gnu.org>, Mats Lidell" . "matsl@gnu.org"))

Same thing.

> Assuming this isn't a red herring, will this perceived dichotomy hold
> going forward? That is, can we count on releases at the /packages
> endpoint being of the improper-list variety and not the alist variety
> for the foreseeable future?

No.

> If so, then I guess this bug is much ado about nothing and can be
> closed, since ERC 5.6+ will be installable on 27+ in the manner
> recommended in our docs.

Its installable via `package-install`, but not from the
`package-menu-describe-package` because of this bug in that command.


        Stefan