services.flatpak.uninstallUnmanaged has invalid default value

[eclairevoyant]

Tested with nixos-rebuild build --flake . with the following:

flake.nix

# flake.nix
{
  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
    flatpak.url = "github:gmodena/nix-flatpak";
  };

  outputs =
    {
      self,
      nixpkgs,
      flatpak,
    }:
    {
      nixosConfigurations.test = nixpkgs.lib.nixosSystem {
        modules = [
          (
            { modulesPath, pkgs, ... }:
            {
              imports = [
                "${modulesPath}/profiles/minimal.nix"
                flatpak.nixosModules.nix-flatpak
              ];

              boot.loader.grub.enable = false;
              fileSystems."/".device = "nodev";
              nixpkgs.hostPlatform = "x86_64-linux";
              system.stateVersion = "24.05";

              services.flatpak.enable = true;
              xdg.portal = {
                enable = true;
                extraPortals = [ pkgs.xdg-desktop-portal-gtk ];
                config.common.default = [ "gtk" ];
              };
            }
          )
        ];
      };
    };
}

Which produces the following error:

error:
       … while calling the 'head' builtin
         at /nix/store/cb1gs888vfqxawvc65q1dk6jzbayh3wz-source/lib/attrsets.nix:1541:11:
         1540|         || pred here (elemAt values 1) (head values) then
         1541|           head values
             |           ^
         1542|         else

       … while evaluating the attribute 'value'
         at /nix/store/cb1gs888vfqxawvc65q1dk6jzbayh3wz-source/lib/modules.nix:809:9:
          808|     in warnDeprecation opt //
          809|       { value = builtins.addErrorContext "while evaluating the option `${showOption loc}':" value;
             |         ^
          810|         inherit (res.defsFinal') highestPrio;

       (stack trace truncated; use '--show-trace' to show the full trace)

       error: expected a Boolean but found null: null
       at /nix/store/9h5mvnz9wn5q3bf55q6r4iyvmdsvdw4g-source/modules/options.nix:177:66:
          176|     type = with types; bool;
          177|     default = config.services.flatpak.uninstallUnmanagedPackages || false;
             |                                                                  ^
          178|     description = lib.mdDoc ''

This is because the default value of the option services.flatpak.uninstallUnmanagedPackages is null, but null || false is not a valid expression in nix.

Even if null || false was valid, the option services.flatpak.uninstallUnmanaged is type bool (not nullOr bool) so this option couldn't take null anyway.

[gmodena]

Hey @eclairevoyant ,

I did an oepsie with integration tests and this bug slipped in. Hotfix incoming.

A workarond for this would be to explicitly set services.flatpak.uninstallUnmanagedPackages = false in your config.