宋文武 <iyzsong@gmail.com> skribis:

> Or better to generate a 'profile' script for each manifest, and then
> merged in shell level, so it can work out-of-the-box. How about:
>   - /etc/profile:
>     # configuration for the whole system goes here.
>     # shouldn't refer profile paths.
>     export LANG=en_US.utf8
>     export SSL_CERT_DIR=/etc/ssl/certs
>     export LINUX_MODULE_DIRECTORY=/run/booted-system/kernel/lib/modules
>     [...]
>
>     source /run/current-system/profile/etc/profile
>
>     if [ -f $HOME/.guix-profile/etc/profile ]; then
>       source $HOME/.guix-profile/etc/profile
>     fi
>
>     # honor setuid-programs
>     export PATH=/run/setuid-programs:$PATH
>
>   - /run/current-system/profile/etc/profile:
>     export PATH=/run/current-system/profile/bin:/run/current-system/profile/sbin:$PATH
>     export MANPATH=/run/current-system/profile/share/man:$PATH
>     [...]
>     
>   - ~/.guix-profile/etc/profile:
>     export PATH=~/.guix-profile/bin:~/.guix-profile/sbin:$PATH
>     [...]

There’s a further complication here: ‘profile-derivation’, which builds
the profile, doesn’t know its user-visible name ~/.guix-profile.  It
just knows its store file name.  However, we don’t want etc/profile to
read:

  export PATH=/gnu/store/...-profile/bin:$PATH

because then, the user’s environment variables in a running session
would keep pointing to a given profile generation.

So we have to tell ‘profile-generation’ what the user-visible name of
the profile is going to be.  Attached is a very rough patch to do that.
This is not so nice because all user interfaces will now have to pass
that #:target parameter or etc/profile will be “wrong.”

Another option would be to simply run:

  eval `guix package -p ~/.guix-profile --search-paths`

This has two downsides:

  1. It takes ~200 ms to run on my laptop, which can maybe be
     noticeable; OTOH it’s only for interactive shells, so maybe that’s
     OK.

  2. If there’s a manifest format change and /etc/profile calls a ‘guix’
     command that cannot handle the manifest format (because it’s older
     than the ‘guix’ used to build the profile), then it doesn’t work at
     all (that’s a bit contrived, but not completely impossible.)

Thoughts?

Ludo’.