nixos/kanata: check the config file at build time

Before this patch, checking the config file is done at runtime.
Doing so at build time shortens the feedback loop[1][2].

[1]: https://github.com/NixOS/nixpkgs/issues/278135
[2]: https://github.com/jtroo/kanata/issues/689

1 files changed, 14 insertions, 8 deletions

diff --git a/nixos/modules/services/hardware/kanata.nix b/nixos/modules/services/hardware/kanata.nix
index 333b2d2a88a5..a88c993bf091 100644
--- a/nixos/modules/services/hardware/kanata.nix
+++ b/nixos/modules/services/hardware/kanata.nix
@@ -86,14 +86,20 @@ let
     in
     optionalString ((length devices) > 0) "linux-dev (${devicesString})";
 
-  mkConfig = name: keyboard: pkgs.writeText "${mkName name}-config.kdb" ''
-    (defcfg
-      ${keyboard.extraDefCfg}
-      ${mkDevices keyboard.devices}
-      linux-continue-if-no-devs-found yes)
-
-    ${keyboard.config}
-  '';
+  mkConfig = name: keyboard: pkgs.writeTextFile {
+    name = "${mkName name}-config.kdb";
+    text = ''
+      (defcfg
+        ${keyboard.extraDefCfg}
+        ${mkDevices keyboard.devices}
+        linux-continue-if-no-devs-found yes)
+
+      ${keyboard.config}
+    '';
+    checkPhase = ''
+      ${getExe cfg.package} --cfg "$target" --check --debug
+    '';
+  };
 
   mkService = name: keyboard: nameValuePair (mkName name) {
     wantedBy = [ "multi-user.target" ];