[Nix-dev] Please test Nix store auto-optimise

[James Cook]

> Once I wondered if using reflinks instead of hardlinks might be better from
> some point of view, but it probably won't be a big difference.

I would really like to see reflinks being used instead of hard links
on filesystems that support it. Hard linking is an impurity which can
cause bugs, as Wout pointed out at the start of the thread (e.g.
https://github.com/NixOS/nixpkgs/issues/4266).

Implementation question: how would nix know when it can delete a file
in /nix/store/.links? I assume than now it just checks the number of
links, but I don't know if you can do that with reflinks.

James