Re: How do package.el handles "duplicate packages"?

[Stefan Monnier via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>]

Eduardo Ochs [2022-11-24 20:43:00] wrote:
> where can I find information on how package.el handles packages that
> are listed twice in the buffer that `M-x list-packages' creates?

Hmm... in `package.el`?

More seriously, I don't think it's clearly documented there, so better
ask more precise questions.

> and I run `M-x my-p1' on the line with the first "afternoon-theme" and
> `M-x my-p2' on the second, then I can inspect the variables my-p1 and
> my-p2 with:
>
>   (describe-variable 'my-p1)
>   (describe-variable 'my-p2)
>
> One of them has these entries,
>
>   :version (0 1)
>   :archive "nongnu"
>
> and the other has these:
>
>   :version (20140104 1859)
>   :archive "melpa"
>
> and if I run this,
>
>   (setq my-ps
>     (cl-loop for (name pdesc) in package-archive-contents
>              if (eq name 'afternoon-theme)
>              collect (list name pdesc)))
>
>   (describe-variable 'my-ps)
>
> I see only one entry in package-archive-contents - the one in MELPA...

As the docstring of `package-archive-contents` describes, there should
be only one entry for `afternoon-theme` but that entry should contain
two `package-desc` objects: one for Melpa and one for NonGNU.


        Stefan