bugfix: MustBeAssigned won't be triggered for prefab assets

Attributes/AutoPropertyAttribute.cs

@@ -112,6 +112,7 @@ static AutoPropertyHandler()
 			PrefabStage.prefabStageOpened += stage => CheckComponentsInPrefab(stage.prefabContentsRoot);
 		}
 
+		// TODO: GetFieldsWithAttribute is slow, should be optimized
 		private static void CheckAssets() => MyEditor
 			.GetFieldsWithAttribute<AutoPropertyAttribute>()
 			.ForEach(FillProperty);

Attributes/MustBeAssignedAttribute.cs

@@ -36,26 +36,33 @@ static MustBeAssignedAttributeChecker()
 		}
 
 		private static void AssertComponentsInScene()
-		{ 
-			AssertComponent(MyEditor.GetAllUnityObjects());
+		{
+			//TODO: Optimize here, we need to check only instantiated behaviours AND ScriptableObject assets
+			AssertComponent(MyEditor.GetAllUnityObjects(), true);
 		}
 
 		private static void AssertComponentsInPrefab(GameObject prefab)
 		{
 			MonoBehaviour[] components = prefab.GetComponentsInChildren<MonoBehaviour>();
-			AssertComponent(components);
+			// ReSharper disable once CoVariantArrayConversion
+			AssertComponent(components, false);
 		}
 
-		private static void AssertComponent(UnityEngine.Object[] objects)
+		private static void AssertComponent(UnityEngine.Object[] objects, bool excludePrefabs)
 		{
 			foreach (var obj in objects)
 			{
 				if (obj == null) continue;
+				if (!(obj.Is<MonoBehaviour>() || obj.Is<ScriptableObject>())) continue;
+
 				Type typeOfScript = obj.GetType();
 				FieldInfo[] mustBeAssignedFields = typeOfScript
 					.GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
 					.Where(field => field.IsDefined(typeof(MustBeAssignedAttribute), false)).ToArray();
+				if (mustBeAssignedFields.IsNullOrEmpty()) continue;
 
+				if (excludePrefabs && PrefabUtility.IsPartOfPrefabAsset(obj)) continue;
+
 				foreach (FieldInfo field in mustBeAssignedFields)
 				{
 					object propValue = field.GetValue(obj);

Extensions/EditorExtensions/MyEditor.cs

@@ -167,11 +167,11 @@ private static GUIContent[] GetTextures(string baseName, string postFix, int sta
 		/// Get all fields with specified attribute on all Unity Objects
 		/// </summary>
 		public static IEnumerable<ObjectField> GetFieldsWithAttribute<T>(
-			GameObject prefab = null) where T : Attribute
+			GameObject parent = null) where T : Attribute
 		{
-			var allObjects = prefab == null ?
+			var allObjects = parent == null ?
 				GetAllUnityObjects() :
-				prefab.GetComponentsInChildren<MonoBehaviour>();
+				parent.GetComponentsInChildren<MonoBehaviour>();
 			return allObjects.Where(obj => obj != null)
 				.SelectMany(obj => obj.GetType()
 					.GetFields(BindingFlags.Public
@@ -214,6 +214,7 @@ public ObjectField(FieldInfo field, Object context)
 		/// </summary>
 		public static Object[] GetAllUnityObjects()
 		{
+			// TODO: First call after Domain Reload is extremely slow, should be optimized
 			LoadAllAssetsOfType(typeof(ScriptableObject));
 			LoadAllAssetsOfType("Prefab");
 			return Resources.FindObjectsOfTypeAll(typeof(Object));