nix-required-mounts: The experimental nix-command feature is required, but not enabled

Nixpkgs version

• Unstable (25.11)

Describe the bug

nix-required-mounts attempts to run nix show-derivation, but the nix-command feature is not guaranteed to be enabled. It should probably add --extra-experimental-features nix-command to the invocation.

Steps to reproduce

1. Enable nix-required-mounts without enabling the nix-command feature
2. Build a package

Expected behaviour

nix-required-mounts should work regardless of the system Nix settings

Screenshots

No response

Relevant log output

this derivation will be built:
  /nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-package.drv
ERROR:root:Couldn't parse the output of`nix show-derivation`. Expected JSON, observed: b''
ERROR:root:
building '/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-package.drv'...

Additional context

No response

System metadata

N/A

Notify maintainers

@SomeoneSerge

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The invocation is in pkgs/by-name/ni/nix-required-mounts/nix_required_mounts.py at lines 123-130. Start by reproducing the build with the nix-command feature disabled, then inspect the nix show-derivation call. Done means nix-required-mounts can parse the derivation output without requiring a system-wide experimental-feature setting.