discord: use new enable option for testbed

flake/packages.nix

@@ -7,46 +7,28 @@
 {
 
   perSystem =
-    {
-      pkgs,
-      system,
-      config,
-      ...
-    }:
+    { pkgs, config, ... }:
     {
       # Build all packages with 'nix flake check' instead of only verifying they
       # are derivations.
       checks = config.packages;
 
-      packages =
-        let
-          testbedPackages = import "${self}/stylix/testbed.nix" {
+      packages = lib.mkMerge [
+        # Testbeds are virtual machines based on NixOS, therefore they are
+        # only available for Linux systems.
+        (lib.mkIf pkgs.stdenv.hostPlatform.isLinux (
+          import "${self}/stylix/testbed.nix" {
             inherit pkgs inputs lib;
-          };
-
-          # Discord is not available on arm64. This workaround filters out
-          # testbeds using that package, until we have a better way to handle
-          # this.
-          testbedPackages' =
-            if system == "aarch64-linux" then
-              lib.filterAttrs (
-                name: _: !lib.hasPrefix "testbed:discord:vencord" name
-              ) testbedPackages
-            else
-              testbedPackages;
-        in
-        lib.mkMerge [
-          # Testbeds are virtual machines based on NixOS, therefore they are
-          # only available for Linux systems.
-          (lib.mkIf pkgs.stdenv.hostPlatform.isLinux testbedPackages')
-          {
-            docs = pkgs.callPackage "${self}/doc" {
-              inherit inputs;
-              inherit (inputs.nixpkgs.lib) nixosSystem;
-              inherit (inputs.home-manager.lib) homeManagerConfiguration;
-            };
-            palette-generator = pkgs.callPackage "${self}/palette-generator" { };
           }
-        ];
+        ))
+        {
+          docs = pkgs.callPackage "${self}/doc" {
+            inherit inputs;
+            inherit (inputs.nixpkgs.lib) nixosSystem;
+            inherit (inputs.home-manager.lib) homeManagerConfiguration;
+          };
+          palette-generator = pkgs.callPackage "${self}/palette-generator" { };
+        }
+      ];
     };
 }

modules/discord/testbeds/vencord.nix

@@ -6,9 +6,14 @@ let
   };
 in
 {
-  stylix.testbed.ui.application = {
-    name = "discord";
-    inherit package;
+  stylix.testbed = {
+    # Discord is not available on arm64.
+    enable = lib.meta.availableOn pkgs.stdenv.hostPlatform package;
+
+    ui.application = {
+      name = "discord";
+      inherit package;
+    };
   };
 
   environment.systemPackages = [ package ];