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

[J.P.]

Hi Philip,

"J.P." <jp@neverwas.me> writes:

>>> Please let me know if anything is required from ERC to make this a
>>> reality. And, of course, I very much appreciate your taking the time.
>>
>> Nothing specific on ERC's side, no.
>> But patches for `elpa-admin.el` and for Emacs would be welcome
>> (tho extra time would be welcome as well :-)
>
> As far as patches go, I unfortunately remain rather uninitiated to the
> mysteries of this package system and doubt I can up my game sufficiently
> enough to amount to anything more than a sad annoyance. However, I can
> try harassing other package.el folk to see if any among them might bend.
> Thanks.

You seem to be among the more active Emacs contributors in and around
package.el and GNU ELPA, so I suppose I'm asking if you wouldn't mind
weighing in on this when you get a chance.

To summarize, I've belatedly discovered that once ERC 5.6 is released,
the more-or-less widely acknowledged [1] "baseline" package-upgrade
method (of manually navigating the `package-menu-mode' UI from M-x
list-packages) won't actually work on any ERC-supported Emacs release
(currently 27+) even though it's the one method recommended in ERC's
docs (expressly because it was perceived as being fail-safe). And while
C-u M-x package-install RET does in fact work on Emacs 29, it's sadly
not documented in the ERC manual that ships with 29.2.

Stefan has suggested renaming the `:maintainer' item in the `extras'
slot of `package-desc' objects to `:maintainers' (plural). IIUC, this
would have the effect of solving the issue by omitting the "Maintainer:"
line item in *Help* buffers produced by `package-menu-describe-package'
and friends for all packages on all Emacs versions below 30.1. Full
remediation would, I think, also require that foo-pkg.el files and
/archive-contents data hosted on elpa.gnu.org reflect the newer format.

To help move this process along, Stefan has called for patches, but I
unfortunately am unable to reciprocate because I lack the wherewithal.
Hoping you're able to assist in this regard either directly, with code,
or by pointing out specific areas in the Emacs code base (and possibly
elpa-admin's as well) that would need addressing.

TIA,
J.P.

[1] https://lists.gnu.org/archive/html/bug-gnu-emacs/2024-01/msg01575.html