Re: wishlist: “repack” generations history of profile

["Ludovic Courtès" <ludo@gnu.org>]

Hello!

zimoun <zimon.toutoune@gmail.com> skribis:

> The question is what to do when we delete?
>
> I am proposing to delete the content, i.e., all but keep the meta, i.e.,
> the file manifest.  We could have an option soft (keep meta) and hard
> (remove all, meta included, as today) for guix gc.

Exactly!  ‘guix pull’ profiles are entirely reproducible: we can rebuild
them from the output of ‘guix describe’.

So ‘guix gc’ (or something) could automatically remove old generation
symlinks and instead store the output of ‘guix describe’.  That way,
‘--list-generations’ or ‘--switch-generations’ could transparently
display the info or rebuild the generation.

System and Home generations are usually, but not necessarily,
reproducible: usually the channel info + config file are enough to
rebuild them, but in theory the config file might refer to resources not
known to Guix (e.g., SSH key files, modules, whatever).  That said, we
could arrange so that ‘guix gc -d’ keeps the metadata around.

For regular profiles, we might do the same, but no guarantee we can
rebuild them, unless all the packages come from the same channels (which
is the case if the profile was built with ‘guix package -m’).

Ludo’.