That is very cool! I would imagine that even if they didn’t implement explicit cloning, APFS would still clone the files.
`nix-store --optimize` is a little different because it looks for duplicates and hardlinks those files across all of the packages. I don’t know how much additional savings that would yield with a typical uv site-packages, but it guarantees no duplicate files.
https://docs.astral.sh/uv/reference/settings/#link-mode
It's even the default. Here's where it's implemented if you're curious https://github.com/astral-sh/uv/blob/f394f7245377b6368b9412d...