error: experimental Nix feature 'nix-command' is disabled; add '--extra-experimental-features nix-command' to enable it

[Kommynct]

doas nh os switch --bypass-root-check --file /etc/nixos/configuration.nix
! Bypassing root check, now running nix as root (nh/src/nixos.rs:76)
> Building NixOS configuration
error: experimental Nix feature 'nix-command' is disabled; add '--extra-experimental-features nix-command' to enable it
┏━ 1 Errors:
┃ error: experimental Nix feature 'nix-command' is …
┣━━━                                               …
┗━ ∑ ⚠ Exited with 1 errors reported by nix at 10:3…
Error:
   0: Command exited with status Exited(1)

Location:
   src/commands.rs:261

sorry i'm new to nixos and have no idea what this error means, i didn't see anything in the install instructions either

same issue with nh os switch -f '<nixpkgs/nixos>'

[NotAShelf]

Try passing or exporting NH_NO_CHECKS=1. This shouldn't be happening without flakes, though.

[Kommynct]

NH_NO_CHECKS=1 nh os switch -f '<nixpkgs/nixos>'                                                               (08-28 12:04)
> Building NixOS configuration
error: experimental Nix feature 'nix-command' is disabled; add '--extra-experimental-features nix-command' to enable it
┏━ 1 Errors:
┃ error: experimental Nix feature 'nix-command' is disabled; add '--extra-experimental-features nix-command' to enable it
┣━━━
┗━ ∑ ⚠ Exited with 1 errors reported by nix at 12:05:04 after 0s
Error:
   0: Command exited with status Exited(1)

Location:
   src/commands.rs:261

same thing

[NotAShelf]

Sorry, I couldn't read the eerror message very well on my phone prior.

This error comes from Nix itself, due to the fact that we are invoking nix build to build your system closure. You can resolve the error by adding nix-commaand to nix.settings.extra-experimental-features in your configuration.nix and rebuilding your system. nh os and friends will work as expeected once you see nix-command in /etc/nix/nix.conf

[Kommynct]

at /etc/nixos/sys.nix:232:46:
          231| };
          232| nix.settings.extra-experimental-features = [ nix-command ];
             |                                              ^
          233|
warning: could not build a newer version of nixos-rebuild, using current version
building the system configuration...
error:

still not working and i can't help but notice there is no option mentioned in nixos search, i think the installation documentation should be updated or enabling nh should enable that setting by itself

[NotAShelf]

Has to be a string: "nix-command"

Also, the option nix.settings is freeform so the sub-attribute doesn't show up. I'm going to add nix-command to required features check for the next release.

[Kommynct]

You should also clarify the error message, I was completely lost, glad that's probably sorted now, there's a build failure on one of my packages so I'll test if it actually worked later, thanks for the help!