bug#62720: 29.0.60; Not easy at all to upgrade :core packages like Eglot

[Eli Zaretskii]

> From: Philip Kaludercic <philipk@posteo.net>
> Cc: joaotavora@gmail.com,  monnier@iro.umontreal.ca,  62720@debbugs.gnu.org,
>   larsi@gnus.org
> Date: Thu, 13 Apr 2023 07:38:28 +0000
> 
> > Thanks.  This is almost on-target, but it modifies
> > package-compute-transaction.  Is that necessary?
> 
> I have found an alternative that doesn't change the way
> `package-compute-transaction' works, but requires a small change in
> `package-install':

Thanks.

> @@ -2205,11 +2218,13 @@ package-install
>       (package--archives-initialize)
>       (list (intern (completing-read
>                      "Install package: "
> -                    (delq nil
> -                          (mapcar (lambda (elt)
> -                                    (unless (package-installed-p (car elt))
> -                                      (symbol-name (car elt))))
> -                                  package-archive-contents))
> +                    (mapcan
> +                     (lambda (elt)
> +                       (and (or (and current-prefix-arg
> +                                     (package--upgradable-built-in-p (car 
> elt)))
> +                                (not (package-installed-p (car elt))))
> +                            (list (car elt))))
> +                     package-archive-contents)

Why did the original code use symbol-name, but the new one doesn't?

> @@ -2221,11 +2236,16 @@ package-install
>        (package--save-selected-packages
>         (cons name package-selected-packages)))
>      (if-let* ((transaction
> -               (if (package-desc-p pkg)
> -                   (unless (package-installed-p pkg)
> -                     (package-compute-transaction (list pkg)
> -                                                  (package-desc-reqs pkg)))
> -                 (package-compute-transaction () (list (list pkg))))))
> +               (cond
> +                ((package--upgradable-built-in-p pkg)
> +                 (let ((desc (cadr (assq name package-archive-contents))))
> +                   (package-compute-transaction
> +                    (list desc) (package-desc-reqs desc))))
> +                ((package-desc-p pkg)
> +                 (and (not (package-installed-p pkg))
> +                      (package-compute-transaction
> +                       (list pkg) (package-desc-reqs pkg))))
> +                ((package-compute-transaction () (list (list pkg)))))))

I think the first condition of 'cond' should be

    ((and current-prefix-arg (package--upgradable-built-in-p pkg))

to make sure we don't affect the non-prefix-arg invocations in any
way.

> Note that (package-install 'eglot) does download code, but I believe
> that this is the correct approach and would align with what João
> wanted.

I'm not sure I follow: which code does the above download?