Could system-manager use a different store than /nix/store ?

[layus]

I am in a weird situation where /nix/store is abused to do other things on my ubuntu machine, but I would like to be able to use system manager too.

In theory, how hard would it be to use a different store location for system-manager ?

I can see that running services and other programs would require some wrapping, maybe in nix-run, maybe something else.
Symlinks could point at the custom store, should be easy.
Anything else obvious I am missing ?

[r-vdp]

You can, and most things will actually transparently adapt because most (all?) store paths you have in outputs are interpolated by nix and will use the new store.

However, you will lose the binary cache completely, since the store location is embedded in build outputs everywhere and therefore it's part of the drv. A different store location will change all hashes.

So it can be done without any particular support from system manager (if we hard code the store location anywhere currently, we could fix that), but you'll do a full bootstrap of your closure from source, which can take a very long time depending on your hardware.

[layus]

Indeed, should have been more clear.

I was thinking of nix --store /home/layus/.cache/system-manager/store run 'github:numtide/system-manager' -- --nix-option store /home/layus/.cache/system-manager/store build for example. A different --store, not a different nix store root.