bug#57503: 28.1.91; package-selected-packages should not be saved to custom-file

[Philip Kaludercic <philipk@posteo.net>]

Joost Kremers <joostkremers@fastmail.fm> writes:

> The variable `package-selected-packages` should not be saved to the users init
> file (or whatever `custom-file` points to). This was discussed before on
> emacs-devel but wasn't resolved:
>
> <https://lists.gnu.org/archive/html/emacs-devel/2016-02/msg00958.html> but 
>
> The gist of it is that if you keep your configuration under version control,
> having package-selected-packages written to your config file is inconvenient if
> you share your config across multiple machines but do not want to have the exact
> same set of packages installed on each.
>
> Even if you do want to keep the exact same set of packages on each machine, you
> still need to be careful about installing them, because the order of package
> installation affects the order of package-selected-packages, and so does
> deleting and reinstalling a package. As a result, I often experienced
> meaningless VC conflicts that needed to be resolved.
>
> IMHO the value of package-selected-packages should be written to a separate
> file, so that it's possible to put it under version control or ignore it,
> independently from the rest of one's configuration.

How about writing it into a file like "~/.config/emacs/elpa/selected-packages"?