flake.nix

{
  description = "Swiss-knife for updating nix packages.";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    flake-parts.url = "github:hercules-ci/flake-parts";
    flake-parts.inputs.nixpkgs-lib.follows = "nixpkgs";

    treefmt-nix.url = "github:numtide/treefmt-nix";
    treefmt-nix.inputs.nixpkgs.follows = "nixpkgs";
  };

  outputs =
    inputs@{ flake-parts, ... }:
    flake-parts.lib.mkFlake { inherit inputs; } (
      { lib, ... }:
      {
        imports = [ ./treefmt.nix ];
        systems = [
          "aarch64-linux"
          "x86_64-linux"
          "riscv64-linux"

          "x86_64-darwin"
          "aarch64-darwin"
        ];
        perSystem =
          {
            config,
            pkgs,
            self',
            ...
          }:
          {
            packages.nix-update = pkgs.callPackage ./. { };
            packages.default = config.packages.nix-update;

            devShells.default = pkgs.mkShell {
              inputsFrom = [ config.packages.default ];

              # Make tests use our pinned Nixpkgs
              env.NIX_PATH = "nixpkgs=${pkgs.path}";
            };

            checks =
              let
                packages = lib.mapAttrs' (n: lib.nameValuePair "package-${n}") self'.packages;
                devShells = lib.mapAttrs' (n: lib.nameValuePair "devShell-${n}") self'.devShells;
              in
              packages // devShells;
          };
      }
    );
}