nixos/garage: add assertion for replication_factor

  };

  config = mkIf cfg.enable {

    assertions = [

      # We removed our module-level default for replication_mode. If a user upgraded

      # to garage 1.0.0 while relying on the module-level default, they would be left

      # with a config which evaluates and builds, but then garage refuses to start

      # because either replication_factor or replication_mode is required.

      # This assertion can be removed in NixOS 24.11, when all users have been warned once.

      {

        assertion = (cfg.settings ? replication_factor || cfg.settings ? replication_mode) || lib.versionOlder cfg.package "1.0.0";

        message = ''

          Garage 1.0.0 requires an explicit replication factor to be set.

          Please set replication_factor to 1 explicitly to preserve the previous behavior.

          https://git.deuxfleurs.fr/Deuxfleurs/garage/src/tag/v1.0.0/doc/book/reference-manual/configuration.md#replication_factor

        '';

      }

    ];

    environment.etc."garage.toml" = {

      source = configFile;

    };