Combined Manager debugging

flake.nix

{
  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";

  outputs =
    inputs:
    let
      lib = inputs.nixpkgs.lib;
      combinedManagerToNixosConfig =
        config:
        config
        // {
          class = "nixos";
          options = config.options.os;
          config = config.config.os;
        };
    in
    {
      nixosConfigurations.default = combinedManagerToNixosConfig (
        lib.evalModules {
          modules = [
            (
              { options, config, ... }:
              {
                options = {
                  os = lib.mkOption {
                    type = lib.types.submoduleWith {
                      modules =
                        import "${inputs.nixpkgs}/nixos/modules/module-list.nix"
                        ++ [
                          {
                            nixpkgs.system = "x86_64-linux"; # Required for some module args
                          }
                        ]
                        ++ [
                          (
                            { config, lib, ... }:
                            {
                              options = {
                                environment.persistence = lib.mkOption {
                                  default = { };
                                  type =
                                    with lib.types;
                                    attrsOf (
                                      lib.types.submodule (
                                        { name, ... }:
                                        {
                                          options = {
                                            persistentStoragePath = lib.mkOption {
                                              type = path;
                                              default = name;
                                            };

                                            files = lib.mkOption {
                                              default = [ ];
                                              type = listOf (submodule {
                                                options = {
                                                  persistentStoragePath = lib.mkOption {
                                                    type = path;
                                                    default = config.environment.persistence.${name}.persistentStoragePath;
                                                  };
                                                  file = lib.mkOption { type = str; };
                                                };
                                              });
                                            };
                                          };
                                        }
                                      )
                                    );
                                };
                              };

                              config.systemd.services."${(lib.head config.environment.persistence."/persist/system".files)
                                .persistentStoragePath
                              }" = { };
                            }
                          )
                        ];
                    };
                  };
                };

                config = {
                  os.environment.persistence."/persist/system".files = [ { file = "/test"; } ];
                  impermanence.files = [ { file = "/etc/test"; } ];
                };

                imports = [
                  {
                    options.impermanence.files =
                      (lib.evalModules {
                        modules =
                          [ { _module.args.name = "/persist/system"; } ]
                          ++ (options.os.type.getSubOptions [ ])
                          .environment.persistence.type.nestedTypes.elemType.getSubModules;
                      }).options.files;

                    config.os.environment.persistence."/persist/system".files = config.impermanence.files;
                  }
                ];
              }
            )
          ];
        }
      );
    };
}