dream2nix/v1/nix/modules/flake-parts/apps.update-caches.nix

{ self, lib, inputs, ... }: {
  perSystem = { config, self', inputs', pkgs, system, ... }: let

    l = lib // builtins;

    allNewFileCommands = l.flatten
      (l.mapAttrsToList
      (name: pkg: pkg.eval-cache.refresh or [])
      self'.packages);

    update-caches = config.writers.writePureShellScript
      (with pkgs; [
        coreutils
        git
        nix
      ])
      (
        "set -x\n"
        + (l.concatStringsSep "\n" allNewFileCommands)
      );

    toApp = script: {
      type = "app";
      program = "${script}";
    };

  in {
    apps = l.mapAttrs (_: toApp) {
      inherit
        update-caches
        ;
    };
  };
}