[edolstra]

It's because Nix wants to install into /nix. Once upon a time doing "sudo mkdir /nix" wasn't a problem, but recent macOS releases have made that very hard.

Nix could switch to an alternate location on macOS (e.g. /opt/nix) but that has a lot of downsides for interoperability with other systems.

[qudat]

Yikes, I had no idea. What a tough pill to swallow all because the directory nix runs out of is hardcoded.

[grhmc]

On Linux, users can put their Nix store in their home directory or other places and at run-time Nix remaps the directory using user namespaces. Unfortunately this isn't workable on macOS: the kernel doesn't support the features we need.

Using /nix and a separate group and daemon means the store can be read-only and be protected from modification in several ways. This is pretty helpful, as a lot of tools try very hard to write "next to" where they are installed -- corrupting the Nix store.

I sort of wonder if it would be more palatable if the Nix installer was a bit less in your face about what's going on? This would be similar to how Docker's works.

[Macha]

This is inherent to having binary packages. Binaries compiled to look for libraries in one location cannot just be copied to a system with a different layout. Nix also can't just use the OS conventions, since part of the point of Nix is that it does not use the global system state and only its own isolated, reproducible world. So then they had to make a decision and decided to just use /nix everywhere which worked fine for some years. And now MacOS has changed, choosing something else would invalidate all historical binary packages.

[vamega]

It's not hardcoded, but you end can't take advantage of the binary caches if you change the directory. A company could certainly create their own binary cache and distribute that to it's users.

[ParetoOptimal]

> What a tough pill to swallow all because the directory nix runs out of is hardcoded.

Yikes? Well then... how would you solve remote binary caching with something like Nix on a platform such as OSX without userns remapping support?

[kaba0]

It’s not actually hardcoded, but you would have to compile everything from scratch as the hash would depend on that as well, throwing out the whole binary cache.