On 2021-10-03 12:50, Liliana Marie Prikler wrote:

> Hi Guix,
>
> it's been a while since the discussion of whether or not to collect
> multiple profiles into a single directory [1].  This suggestion takes
> inspiration from that, but goes a vastly different route.  Instead of
> using environment variables to control Guix, it takes advantage of the
> recently added Guix Home, even if it is still a technical preview.
>
> So, what's the proposition?  I suggest we modify home-profile-service-
> type (or add a new service) such that it takes a list of <home-profile> 
> records instead of a list of packages.  This record would be defined as
>
>   (define-record-type* <home-profile> home-profile
>     make-home-profile home-profile? this-home-profile
>     (location home-profile-location) ; string, e.g. $HOME/.guix-profile
>     (short-name home-profile-short-name) ; string or #f, if given
>                                          ; construct a symlink in
>                                          ; /var/guix/.../per-user/
>     (manifest %home-profile-manifest) ; <manifest> or #f
>     (packages home-profile-packages) ; list of <package> or #f
>                                      ; fallback for manifest
>     (enabled? home-profile-enabled?) ; boolean, default #t
>     [...])
>
>   (define (home-profile-manifest home-profile)
>     (or (%home-profile-manifest home-profile)
>         (and=> (home-profile-packages home-profile) 
>                packages->manifest))))
>
> On init/reconfigure, `guix home' creates/updates all home-profiles
> which have a home-profile-manifest that is not #f and links them to the
> appropriate locations.  It also creates a shell startup script that
> loads those profiles that are enabled?, even if they have no manifest
> (this can be used to e.g. declare a pull profile, which `guix home'
> can't manage).  
>
> Some existing home services would need to be adapted towards this
> multiple profile usage.  For instance, home-fontconfig-service-type
> would need to accept a list of directories, rather than hardcode its
> value.
>
> What do y'all think?
>
> <https://lists.gnu.org/archive/html/guix-devel/2019-12/msg00358.html>
>
>

It seems doable, but not sure about costs and benifits.

Also, cross-profile package installation can be error-prone, for example
if user install an emacs in main profile and emacs packages in emacsy
profile we will end up in a situation, where those emacs package aren't
available in Emacs.  Probably some other issues will become clearer
during implementation.

Another idea I have in mind is to make such profiles (including guix
home's main profile) detached from ~/.config/guix/current.  For example
by providing channels specification as a part of <home-profile>.  It
will make it possible to freeze a costly-to-rebuild profile at a given
channels revisions and not to rebuild it, when the main profile and
channels for it get updated.

-- 
Best regards,
Andrew Tropin