bug#44327: `guix install` doesn't warn about collison in profile

["Ludovic Courtès" <ludo@gnu.org>]

Hi,

Zhu Zihao <all_but_last@163.com> skribis:

> In commit ba60bbd4370570ff03a16c63af051be06f22658e. Try command
>
>   guix install emacs && guix install emacs-xwidgets
>
> These two packages are conflict with each other, but I can't see any
> warning message emitted(It should emit some because profile-derivation
> use union-build).

‘union-build’ emits a warning, but it’s only visible in build logs.

> I also suggest to raise an error when conflict detected during building
> profile to force user to resolve it.

Currently, ‘guix install’ errors out if you try to install two
same-named packages with a different version number or a different store
file name (typically via propagated inputs).

Here, ‘emacs’ and ‘emacs-xwidgets’ have different names, so it doesn’t
complain.

Perhaps we should offer a way to annotate packages as conflicting with
one another?

Thanks,
Ludo’.