Regression 4.0.3 -> 4.1.0 Flakes required when not using flakes

[benjumanji]

~ 
❯ nh os switch -f '<nixpkgs/nixos>' -- -I nixpkgs="$(nixpkgs-path-with-eval)"
! Missing required Nix features: flakes (nh/src/checks.rs:101)
Error: 
   0: Missing required experimental features. Please enable: flakes

Location:
   src/checks.rs:105

I don't use flakes.

[benjumanji]

Seems to have been introduced by 119d6a9

Is there any chance we could improve these checks to only fire if nh actually requires the experimental feature?

[NotAShelf]

Setting NH_NO_CHECKS disables those checks entirely. While subpar, it is the best way of implementing a required features check that doesn't trigger on each command.

[adamjhf]

Getting the same error using Determinate Nix, which has flakes stabilised and enabled by default.

! Missing required Nix features: nix-command, flakes (nh/src/checks.rs:101)
Error:
   0: Missing required experimental features. Please enable: nix-command, flakes

Location:
   src/checks.rs:105

[benjumanji]

Oh, totally missed the env var when skimming. That's good enough for me to get by.

[nikitax44]

Getting the same error using Determinate Nix, which has flakes stabilised and enabled by default.

! Missing required Nix features: nix-command, flakes (nh/src/checks.rs:101)
Error:
   0: Missing required experimental features. Please enable: nix-command, flakes

Location:
   src/checks.rs:105

it is another problem and requires creating separate issue. determinate nix just removed the nix-command and flakes features (they're just always enabled).

nix config show experimental-features does not list nix-command and flakes

[NotAShelf]

Please read the comments in the issue before commenting.

As mentioned before, we do not support DetSys Nix (and I don't intend to respond to their hostility with unwarranted kindness). Simply setting the variable (you can do this globally) will disable the checks.

[NotAShelf]

I've opened #320 to help mitigate this issue. Testing on non-mainstream Nix variants and especially on non-flakes systems (CC @benjumanji) would be appreciated.

[benjumanji]

I'll take a look this weekend, thanks!