Add test to detect JSON defaults vs FeatureFlags struct mismatch

Co-authored-by: Byron <[email protected]>

Author: Copilot

crates/but-settings/assets/defaults.jsonc

@@ -18,15 +18,13 @@
 		"oauthClientId": "cd51880daa675d9e6452"
 	},
 	"featureFlags": {
-		// Deprecated, was used for the new version of the UI.
-		"v3": true,
 		// Enables the v3 safe checkout.
 		"cv3": false,
 		/// Enable the usage of V3 workspace APIs.
 		"ws3": true,
 		/// Enable undo/redo support.
 		"undo": false,
-		/// Enable the usage of GitButler Acitions.
+		/// Enable the usage of GitButler Actions.
 		"actions": false,
 		/// Enable the usage of the butbot chat.
 		"butbot": false,

crates/but-settings/src/persistence.rs

@@ -59,6 +59,8 @@ impl AppSettings {
 }
 
 mod tests {
+    use crate::app_settings::FeatureFlags;
+
     #[test]
     fn ensure_default_settings_covers_all_fields() {
         let settings: serde_json::Value =
@@ -79,4 +81,53 @@ mod tests {
         }
         assert!(app_settings.is_ok())
     }
+
+    #[test]
+    fn ensure_feature_flags_json_defaults_match_struct_defaults() {
+        // Get the feature flags from the JSON defaults file
+        let json_defaults: serde_json::Value =
+            serde_json_lenient::from_str(crate::persistence::DEFAULTS).unwrap();
+        let json_feature_flags = json_defaults
+            .get("featureFlags")
+            .expect("featureFlags should exist in defaults.jsonc");
+
+        // Create what the struct would look like with proper serde defaults
+        // Based on the struct definition, most fields are false except ws3 which has #[serde(default = "default_true")] 
+        let expected_default_feature_flags = FeatureFlags {
+            ws3: true,  // This has #[serde(default = "default_true")] so it should be true
+            cv3: false,
+            undo: false,
+            actions: false,
+            butbot: false,
+            rules: false,
+            single_branch: false,
+        };
+
+        // Serialize the expected default struct to JSON for comparison
+        let expected_default_as_json: serde_json::Value = serde_json::to_value(&expected_default_feature_flags)
+            .expect("Expected default FeatureFlags should be serializable");
+
+        // Compare the JSON values directly - this will catch extra fields like 'v3' that don't exist in the struct
+        if *json_feature_flags != expected_default_as_json {
+            println!("\n===========================================================================================");
+            println!("FeatureFlags JSON defaults don't match the default struct serialization!");
+            println!();
+            println!("JSON from defaults.jsonc:");
+            println!("{}", serde_json::to_string_pretty(json_feature_flags).unwrap());
+            println!();
+            println!("Expected default struct serialized:");
+            println!("{}", serde_json::to_string_pretty(&expected_default_as_json).unwrap());
+            println!();
+            println!("This means the JSON defaults contain fields or values that don't match");
+            println!("the FeatureFlags struct definition. Please update either:");
+            println!("1. The defaults in 'crates/but-settings/assets/defaults.jsonc' (remove extra fields, fix values)");
+            println!("2. The FeatureFlags struct in 'crates/but-settings/src/app_settings.rs' (add missing fields)");
+            println!("===========================================================================================\n");
+        }
+
+        assert_eq!(
+            *json_feature_flags, expected_default_as_json,
+            "FeatureFlags JSON defaults should match the expected default struct when serialized"
+        );
+    }
 }