Unfree packages

Which unfree packages are allowed is configured at the flake level via an option. That is then used in the configuration of Nixpkgs. See definition at unfree-packages.nix. See usage at vscode. The value of this option is available as a flake output:

$ nix eval .#meta.nixpkgs.allowedUnfreePackages

Hosts

The set of NixOS hosts is defined via an option which accepts deferred modules. Differentiating the hosts as a subset of the NixOS modules allows us to map over the hosts without string matching.

See definition at hosts.nix. See usage at autolycus.

Closure Size Checks

Closure sizes for specific configurations are monitored via snapshot tests. These are defined using the closureChecks option and automatically generate flake checks.

The checks use pkgs.closureInfo to avoid IFD (import-from-derivation).

See definition at closureChecks.nix.