Thanks for your review!

However they didn't work with zsh or fish.

I used the completions paths which are commonly used in other nix expressions:
https://github.com/nixos/nixpkgs/blob/c08f80839fc2dda8bfde1f4fd08b08d0403ae487/pkgs/applications/misc/ddgr/default.nix#L21-L24
https://github.com/nixos/nixpkgs/blob/c08f80839fc2dda8bfde1f4fd08b08d0403ae487/pkgs/tools/misc/fd/default.nix#L21-L24

I personally use bash, but I've tested on zsh and seems to be working

I just failed to build this on macOS.

> nix build -f . lsd
builder for '/nix/store/47k8sc0hlqgp7pj00rwwdcaxx8gj9qkb-lsd-0.13.0.drv' failed with exit code 101; last 10 log lines:
  thread 'meta::filetype::test::test_socket_type' panicked at 'failed to create the socket: Custom { kind: InvalidInput, error: StringError("path must be shorter than SUN_LEN") }', src/libcore/result.rs:1009:5
  note: Run with `RUST_BACKTRACE=1` for a backtrace.
  
  
  failures:
      meta::filetype::test::test_socket_type
  
  test result: FAILED. 50 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out
  
  error: test failed, to rerun pass '--bin lsd'

I don't have sandbox enabled in my nix.conf. Is there any chance that sandbox builds with a shorter TMPDIR than the default?

env TMPDIR=/tmp nix build -f . lsd succeeded. Seems rather problematic if this can't be built with the default TMPDIR though.

That is odd, I'm building it on darwin 10.12 without any issue.

$ nix-build -A lsd
/nix/store/hdmzw3rh86vdsldz44k0k8c5x3vdljbv-lsd-0.13.0

maybe nix-daemon is running with sandbox=true, can you try restarting nix-daemon?

I've got a single-user install so no nix-daemon. This is also why I'm not using sandbox (as the docs says that requires sudo, which I'd prefer not to use).

The simplest solution here might just be to disable tests on this package. I notice the exa package is already doing that:

  # Some tests fail, but Travis ensures a proper build
  doCheck = false;