added a check to make sure a situation where a defined configuration wouldn't be unused as per recommended by @maurer

1 files changed, 6 insertions, 0 deletions

diff --git a/nixos/modules/services/monitoring/incron.nix b/nixos/modules/services/monitoring/incron.nix
index edba38140c6..c850bad881c 100644
--- a/nixos/modules/services/monitoring/incron.nix
+++ b/nixos/modules/services/monitoring/incron.nix
@@ -59,6 +59,12 @@ in
 
   config = mkIf cfg.enable {
 
+    assertions = [
+      { assertion = cfg.allow != null -> cfg.deny == null;
+        message = "If `services.incron.allow` is set then `services.incron.deny` will be ignored.";
+      }
+    ];
+
     environment.systemPackages = [ pkgs.incron ];
 
     security.wrappers.incrontab.source = "${pkgs.incron}/bin/incrontab";