bug#48853: [PATCH] profiles: Move some of the work to the build side.

["Ludovic Courtès" <ludo@gnu.org>]

Ludovic Courtès <ludo@gnu.org> skribis:

> When running:
>
>   guix environment --ad-hoc gnome --no-grafts --search-paths
>
> this reduces wall-clock time by ~5%.  The number of object cache lookups
> goes down from 96K to 89K.  (Note that 'gnome' is an interesting example
> because it has many propagated inputs, which themselves have propagated
> inputs too, which would lead to a long input list and a long manifest in
> the 'profile-derivation' gexp.)
>
> * guix/profiles.scm (profile-derivation)[inputs, search-paths]: Remove.
> [extra-inputs]: New variable.
> [builder]: Adjust call to 'build-profile'.
> * guix/build/profiles.scm (manifest-sexp->inputs+search-paths): New
> procedure.
> (build-profile): Remove 'inputs' parameter; make 'manifest' the 2nd
> positional parameter and add #:extra-inputs.  Call
> 'manifest-sexp->inputs+search-paths' to obtain 'inputs' and
> 'search-paths'.
> ---
>  guix/build/profiles.scm | 86 +++++++++++++++++++++++++++--------------
>  guix/profiles.scm       | 25 ++++--------
>  2 files changed, 64 insertions(+), 47 deletions(-)

Pushed as 8cef92d0633850d97c1a1d4521812268f56672be.