Re: installing python 2 and python 3 in the same profile

[Ricardo Wurmus <rekado@elephly.net>]

Ludovic Courtès <ludo@gnu.org> writes:

>> How about a package property that defines a “conflicts?” predicate that
>> takes two packages of the same name and determines (e.g. by checking the
>> major version) if these two packages are conflicting?  If no such
>> predicate is provided we assume that packages with the same name cause a
>> conflict and prevent installation.
>
> Unfortunately it wouldn’t work in the general case where some profile
> entries may be coming from ~/.guix-profile/manifest, as is the case when
> you do:
>
>   guix package -i python@2
>   guix package -i python@3
>
> I would suggest short-term solutions, which are not exclusive:
>
>   1. Add a ‘--allow-collisions’ flag to ‘guix profile’ (we discussed it
>      before but didn’t get around to doing it apparently!).
>
>   2. Use different package names when we know things can be
>      parallel-installed: “python2” vs. “python” (I’m talking about the
>      package name, not its version string.)  That’s what distros usually
>      do, and I think it’s good enough.

Both of these are desirable solutions, I think.  “--allow-collisions”
would be an escape hatch, and renaming packages is much easier than the
“serialisable predicate” idea.

-- 
Ricardo

GPG: BCA6 89B6 3655 3801 C3C6  2150 197A 5888 235F ACAC
https://elephly.net