fnott: refactor module

- Change generation behavior to always generate a configuration file
  and pass it explicitly to fnott, it enforces the module to be
  hermetic instead of offloading the configuration selection to
  heuristics.
- Various style changes.
- Fix issue where fnott would abort due to an invalid config file when
  both the configFile and settings options are unset.
- Remove the empty-settings test as a configuration file is now
  already generated.

Suggested-by: Robert Helgesson <robert@rycee.net>

modules/services/fnott.nix

@@ -6,7 +6,7 @@ let
   cfg = config.services.fnott;
 
   concatStringsSep' = sep: list:
-    concatStringsSep sep (filter (str: str != "") list);
+    concatStringsSep sep (filter (x: x != "") list);
 
   mkKeyValue = generators.mkKeyValueDefault { } "=";
   genINI = generators.toINI { };
@@ -31,6 +31,15 @@ in {
         description = "Package providing <command>fnott</command>.";
       };
 
+      extraFlags = mkOption {
+        type = types.listOf types.str;
+        default = [ ];
+        example = [ "-s" ];
+        description = ''
+          Extra arguments to use for executing fnott.
+        '';
+      };
+
       configFile = mkOption {
         type = types.either types.str types.path;
         default = "${config.xdg.configHome}/fnott/fnott.ini";
@@ -48,15 +57,6 @@ in {
         '';
       };
 
-      extraFlags = mkOption {
-        type = types.listOf types.str;
-        default = [ ];
-        example = [ "-s" ];
-        description = ''
-          Extra arguments to use for executing fnott.
-        '';
-      };
-
       settings = mkOption {
         type = iniFormatType;
         default = { };
@@ -107,24 +107,21 @@ in {
         Type = "dbus";
         BusName = "org.freedesktop.Notifications";
         ExecStart = concatStringsSep' " " [
-          "${cfg.package}/bin/fnott -c ${cfg.configFile}"
+          "${cfg.package}/bin/fnott"
+          "-c ${escapeShellArg cfg.configFile}"
           (escapeShellArgs cfg.extraFlags)
         ];
       };
     };
 
+    xdg.configFile."fnott/fnott.ini" = {
       # FIXME: Remove after next version release (https://codeberg.org/dnkl/fnott/pulls/24).
-    xdg.configFile."fnott/fnott.ini" = mkIf (cfg.settings != { }) (mkMerge [
-      { text = genINI cfg.settings; }
-      (mkIf (cfg.settings ? main) {
-        text = mkForce (concatStringsSep' "\n" [
-          ''
-            ${concatStringsSep "\n"
-            (mapAttrsToList mkKeyValue cfg.settings.main)}
-          ''
+      text = concatStringsSep' "\n" [
+        (optionalString (cfg.settings ? main) ''
+          ${concatStringsSep "\n" (mapAttrsToList mkKeyValue cfg.settings.main)}
+        '')
         (genINI (removeAttrs cfg.settings [ "main" ]))
-        ]);
-      })
-    ]);
+      ];
+    };
   };
 }

tests/modules/services/fnott/default.nix

@@ -1,5 +1,4 @@
 {
-  fnott-empty-settings = ./empty-settings.nix;
   fnott-example-settings = ./example-settings.nix;
   fnott-global-properties = ./global-properties.nix;
   fnott-systemd-user-service = ./systemd-user-service.nix;

tests/modules/services/fnott/empty-settings.nix

@@ -1,15 +0,0 @@
-{ config, lib, pkgs, ... }:
-
-{
-  config = {
-    services.fnott = {
-      enable = true;
-      package = pkgs.writeScriptBin "dummy-fnott" "";
-      settings = { };
-    };
-
-    nmt.script = ''
-      assertPathNotExists home-files/.config/fnott
-    '';
-  };
-}

tests/modules/services/fnott/systemd-user-service-expected.service

@@ -1,6 +1,6 @@
 [Service]
 BusName=org.freedesktop.Notifications
-ExecStart=@fnott@/bin/fnott -c /home/hm-user/.config/fnott/fnott.ini
+ExecStart=@fnott@/bin/fnott -c '/home/hm-user/.config/fnott/fnott.ini'
 Type=dbus
 
 [Unit]

tests/modules/services/fnott/systemd-user-service.nix

@@ -8,8 +8,6 @@
     };
 
     nmt.script = ''
-      assertPathNotExists home-files/.config/fnott/fnott.ini
-
       assertFileContent \
         home-files/.config/systemd/user/fnott.service \
         ${./systemd-user-service-expected.service}