Fix/material array population

Unity-MCP-Plugin/Assets/root/Runtime/Converter/JsonConverters/Types/AssetObjectRefConverter.cs

@@ -51,7 +51,7 @@ public class AssetObjectRefConverter : JsonConverter<AssetObjectRef>
                             assetObjectRef.AssetGuid = reader.GetString();
                             break;
                         default:
-                            throw new JsonException($"Unexpected property name: {propertyName}. "
+                            throw new JsonException($"[AssetObjectRefConverter] Unexpected property name: {propertyName}. "
                                 + $"Expected {AssetObjectRef.AssetObjectRefProperty.All.JoinEnclose()}.");
                     }
                 }

Unity-MCP-Plugin/Assets/root/Runtime/Converter/JsonConverters/Types/GameObjectRefConverter.cs

@@ -50,6 +50,12 @@ public class GameObjectRefConverter : JsonConverter<GameObjectRef>
                         case GameObjectRef.GameObjectRefProperty.Name:
                             result.Name = reader.GetString();
                             break;
+                        case AssetObjectRef.AssetObjectRefProperty.AssetPath:
+                            result.AssetPath = reader.GetString();
+                            break;
+                        case AssetObjectRef.AssetObjectRefProperty.AssetGuid:
+                            result.AssetGuid = reader.GetString();
+                            break;
                         default:
                             throw new JsonException($"Unexpected property name: {propertyName}. "
                                 + $"Expected {GameObjectRef.GameObjectRefProperty.All.JoinEnclose()}.");
@@ -83,6 +89,12 @@ public override void Write(Utf8JsonWriter writer, GameObjectRef value, JsonSeria
             if (!string.IsNullOrEmpty(value.Name))
                 writer.WriteString(GameObjectRef.GameObjectRefProperty.Name, value.Name);
 
+            if (!string.IsNullOrEmpty(value.AssetPath))
+                writer.WriteString(AssetObjectRef.AssetObjectRefProperty.AssetPath, value.AssetPath);
+
+            if (!string.IsNullOrEmpty(value.AssetGuid))
+                writer.WriteString(AssetObjectRef.AssetObjectRefProperty.AssetGuid, value.AssetGuid);
+
             writer.WriteEndObject();
         }
     }

Unity-MCP-Plugin/Assets/root/Runtime/Converter/ReflectionConverters/Base/UnityGenericReflectionConvertor.cs

@@ -13,8 +13,13 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
+using System.Text;
 using com.IvanMurzak.ReflectorNet;
 using com.IvanMurzak.ReflectorNet.Convertor;
+using com.IvanMurzak.ReflectorNet.Model;
+using com.IvanMurzak.ReflectorNet.Utils;
+using com.IvanMurzak.Unity.MCP.Runtime.Extensions;
+using Microsoft.Extensions.Logging;
 using UnityEngine;
 using ILogger = Microsoft.Extensions.Logging.ILogger;
 
@@ -26,5 +31,136 @@ public partial class UnityGenericReflectionConvertor<T> : GenericReflectionConve
             => objType.GetFields(flags)
                 .Where(field => field.GetCustomAttribute<ObsoleteAttribute>() == null)
                 .Where(field => field.IsPublic || field.IsPrivate && field.GetCustomAttribute<SerializeField>() != null);
+
+        public override object? Deserialize(
+            Reflector reflector,
+            SerializedMember data,
+            Type? fallbackType = null,
+            string? fallbackName = null,
+            int depth = 0,
+            StringBuilder? stringBuilder = null,
+            ILogger? logger = null)
+        {
+            var type = fallbackType ?? typeof(T);
+            if (typeof(UnityEngine.Object).IsAssignableFrom(type))
+            {
+                return data.valueJsonElement
+                   .ToAssetObjectRef(reflector, suppressException: true, depth: depth, stringBuilder: stringBuilder, logger: logger)
+                   .FindAssetObject(type);
+            }
+            return base.Deserialize(reflector, data, fallbackType, fallbackName, depth, stringBuilder, logger);
+        }
+
+        protected override bool SetValue(
+            Reflector reflector,
+            ref object? obj,
+            Type type,
+            System.Text.Json.JsonElement? value,
+            int depth = 0,
+            StringBuilder? stringBuilder = null,
+            ILogger? logger = null)
+        {
+            var originalObj = obj;
+            var result = base.SetValue(reflector, ref obj, type, value, depth, stringBuilder, logger);
+
+            // If obj became null but we had an object, and the value didn't explicitly say null, restore it.
+            // This handles cases where TryPopulate is called with an existing object but no valueJsonElement.
+            if (obj == null && originalObj != null)
+            {
+                var isExplicitNull = value.HasValue && value.Value.ValueKind == System.Text.Json.JsonValueKind.Null;
+                if (!isExplicitNull)
+                {
+                    obj = originalObj;
+                }
+            }
+
+            return result;
+        }
+
+        protected override bool TryPopulateField(
+            Reflector reflector,
+            ref object? obj,
+            Type objType,
+            SerializedMember fieldValue,
+            int depth = 0,
+            StringBuilder? stringBuilder = null,
+            BindingFlags flags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic,
+            ILogger? logger = null)
+        {
+            var padding = StringUtils.GetPadding(depth);
+            if (obj == null)
+            {
+                logger?.LogError("{padding}obj is null in TryPopulateField for {field}", padding, fieldValue.name);
+                if (stringBuilder != null)
+                    stringBuilder.AppendLine($"{padding}[Error] obj is null in TryPopulateField for {fieldValue.name}");
+                return false;
+            }
+
+            var field = objType.GetField(fieldValue.name, flags);
+            if (field == null)
+            {
+                logger?.LogError("{padding}Field {field} not found on {type}", padding, fieldValue.name, objType.Name);
+                if (stringBuilder != null)
+                    stringBuilder.AppendLine($"{padding}[Error] Field {fieldValue.name} not found on {objType.Name}");
+                return false;
+            }
+
+            try
+            {
+                var value = reflector.Deserialize(fieldValue, field.FieldType, depth: depth + 1, stringBuilder: stringBuilder, logger: logger);
+                field.SetValue(obj, value);
+                return true;
+            }
+            catch (Exception e)
+            {
+                logger?.LogError(e, "{padding}Failed to set field {field}", padding, fieldValue.name);
+                if (stringBuilder != null)
+                    stringBuilder.AppendLine($"{padding}[Error] Failed to set field {fieldValue.name}: {e.Message}");
+                return false;
+            }
+        }
+
+        protected override bool TryPopulateProperty(
+            Reflector reflector,
+            ref object? obj,
+            Type objType,
+            SerializedMember member,
+            int depth = 0,
+            StringBuilder? stringBuilder = null,
+            BindingFlags flags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic,
+            ILogger? logger = null)
+        {
+            var padding = StringUtils.GetPadding(depth);
+            if (obj == null)
+            {
+                logger?.LogError("{padding}obj is null in TryPopulateProperty for {property}", padding, member.name);
+                if (stringBuilder != null)
+                    stringBuilder.AppendLine($"{padding}[Error] obj is null in TryPopulateProperty for {member.name}");
+                return false;
+            }
+
+            var property = objType.GetProperty(member.name, flags);
+            if (property == null || !property.CanWrite)
+            {
+                logger?.LogError("{padding}Property {property} not found or not writable on {type}", padding, member.name, objType.Name);
+                if (stringBuilder != null)
+                    stringBuilder.AppendLine($"{padding}[Error] Property {member.name} not found or not writable on {objType.Name}");
+                return false;
+            }
+
+            try
+            {
+                var value = reflector.Deserialize(member, property.PropertyType, depth: depth + 1, stringBuilder: stringBuilder, logger: logger);
+                property.SetValue(obj, value);
+                return true;
+            }
+            catch (Exception e)
+            {
+                logger?.LogError(e, "{padding}Failed to set property {property}", padding, member.name);
+                if (stringBuilder != null)
+                    stringBuilder.AppendLine($"{padding}[Error] Failed to set property {member.name}: {e.Message}");
+                return false;
+            }
+        }
     }
 }

Unity-MCP-Plugin/Assets/root/Runtime/Converter/ReflectionConverters/UnityEngine_Asset_ReflectionConvertor.cs

@@ -0,0 +1,139 @@
+/*
+┌──────────────────────────────────────────────────────────────────┐
+│  Author: Ivan Murzak (https://github.com/IvanMurzak)             │
+│  Repository: GitHub (https://github.com/IvanMurzak/Unity-MCP)    │
+│  Copyright (c) 2025 Ivan Murzak                                  │
+│  Licensed under the Apache License, Version 2.0.                 │
+│  See the LICENSE file in the project root for more information.  │
+└──────────────────────────────────────────────────────────────────┘
+*/
+
+#nullable enable
+using System;
+using System.Reflection;
+using System.Text;
+using com.IvanMurzak.ReflectorNet;
+using com.IvanMurzak.ReflectorNet.Model;
+using com.IvanMurzak.ReflectorNet.Utils;
+using com.IvanMurzak.Unity.MCP.Runtime.Extensions;
+using Microsoft.Extensions.Logging;
+using UnityEngine;
+using ILogger = Microsoft.Extensions.Logging.ILogger;
+using LogLevel = Microsoft.Extensions.Logging.LogLevel;
+
+namespace com.IvanMurzak.Unity.MCP.Reflection.Convertor
+{
+    public class UnityEngine_Asset_ReflectionConvertor<T> : UnityEngine_Object_ReflectionConvertor<T> where T : UnityEngine.Object
+    {
+        public override bool TryPopulate(
+            Reflector reflector,
+            ref object? obj,
+            SerializedMember data,
+            Type? dataType = null,
+            int depth = 0,
+            StringBuilder? stringBuilder = null,
+            BindingFlags flags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic,
+            ILogger? logger = null)
+        {
+            var padding = StringUtils.GetPadding(depth);
+
+            if (logger?.IsEnabled(LogLevel.Trace) == true)
+                logger.LogTrace($"{padding}Populate asset from data. Convertor='{GetType().GetTypeShortName()}'.");
+
+            var objectRef = data.valueJsonElement.ToAssetObjectRef(
+                reflector: reflector,
+                depth: depth,
+                stringBuilder: stringBuilder,
+                logger: logger);
+
+            if (objectRef == null)
+            {
+                // If no object ref, maybe we should fall back to base behavior?
+                // But for assets, usually we expect an object ref.
+                // Let's return false to indicate we couldn't populate it as an asset.
+                return false;
+            }
+
+#if UNITY_EDITOR
+            var instanceID = objectRef.InstanceID;
+            if (instanceID != 0)
+            {
+                var loadedObj = LoadFromInstanceID(instanceID);
+                if (loadedObj != null)
+                {
+                    obj = loadedObj;
+                    if (stringBuilder != null)
+                        stringBuilder.AppendLine($"{padding}[Success] Assigned asset from InstanceID: {instanceID}. Convertor: {GetType().GetTypeShortName()}");
+                    return true;
+                }
+
+                if (logger?.IsEnabled(LogLevel.Warning) == true)
+                    logger.LogWarning($"{padding}InstanceID {instanceID} found but failed to load asset. Convertor: {GetType().GetTypeShortName()}");
+            }
+
+            if (!string.IsNullOrEmpty(objectRef.AssetPath))
+            {
+                var loadedObj = LoadFromAssetPath(objectRef.AssetPath);
+                if (loadedObj != null)
+                {
+                    obj = loadedObj;
+                    if (stringBuilder != null)
+                        stringBuilder.AppendLine($"{padding}[Success] Assigned asset from AssetPath: {objectRef.AssetPath}. Convertor: {GetType().GetTypeShortName()}");
+                    return true;
+                }
+
+                if (logger?.IsEnabled(LogLevel.Warning) == true)
+                    logger.LogWarning($"{padding}AssetPath {objectRef.AssetPath} found but failed to load asset. Convertor: {GetType().GetTypeShortName()}");
+            }
+
+            if (!string.IsNullOrEmpty(objectRef.AssetGuid))
+            {
+                var loadedObj = LoadFromAssetGuid(objectRef.AssetGuid);
+                if (loadedObj != null)
+                {
+                    obj = loadedObj;
+                    if (stringBuilder != null)
+                        stringBuilder.AppendLine($"{padding}[Success] Assigned asset from AssetGuid: {objectRef.AssetGuid}. Convertor: {GetType().GetTypeShortName()}");
+                    return true;
+                }
+
+                if (logger?.IsEnabled(LogLevel.Warning) == true)
+                    logger.LogWarning($"{padding}AssetGuid {objectRef.AssetGuid} found but failed to load asset. Convertor: {GetType().GetTypeShortName()}");
+            }
+#endif
+
+            // If we reached here, we failed to find the asset.
+            // Should we set obj to null? The Sprite convertor does.
+            obj = null;
+
+            if (logger?.IsEnabled(LogLevel.Trace) == true)
+                logger.LogTrace($"{padding}[Success] Failed to find asset. Cleared the reference. Convertor: {GetType().GetTypeShortName()}");
+
+            if (stringBuilder != null)
+                stringBuilder.AppendLine($"{padding}[Success] Failed to find asset. Cleared the reference. Convertor: {GetType().GetTypeShortName()}");
+
+            return true;
+        }
+
+#if UNITY_EDITOR
+        protected virtual T? LoadFromInstanceID(int instanceID)
+        {
+            var obj = UnityEditor.EditorUtility.InstanceIDToObject(instanceID);
+            return obj as T;
+        }
+
+        protected virtual T? LoadFromAssetPath(string path)
+        {
+            return UnityEditor.AssetDatabase.LoadAssetAtPath<T>(path);
+        }
+
+        protected virtual T? LoadFromAssetGuid(string guid)
+        {
+            var path = UnityEditor.AssetDatabase.GUIDToAssetPath(guid);
+            if (string.IsNullOrEmpty(path))
+                return null;
+            return LoadFromAssetPath(path);
+        }
+#endif
+    }
+}

Unity-MCP-Plugin/Assets/root/Runtime/Converter/ReflectionConverters/UnityEngine_GameObject_ReflectionConvertor.cs

@@ -148,13 +148,31 @@ protected override bool SetValue(
         {
             var padding = StringUtils.GetPadding(depth);
 
-            if (logger?.IsEnabled(LogLevel.Warning) == true)
-                logger.LogWarning($"{padding}Cannot set value for '{type.GetTypeShortName()}'. This type is not supported for setting values. Maybe did you want to set a field or a property? If so, set the value in the '{nameof(SerializedMember.fields)}' or '{nameof(SerializedMember.props)}' property instead.");
+            if (logger?.IsEnabled(LogLevel.Trace) == true)
+                logger.LogTrace($"{padding}Set value type='{type.GetTypeName(pretty: true)}'. Convertor='{GetType().GetTypeShortName()}'.");
 
-            if (stringBuilder != null)
-                stringBuilder.AppendLine($"{padding}[Warning] Cannot set value for '{type.GetTypeName(pretty: false)}'. This type is not supported for setting values. Maybe did you want to set a field or a property? If so, set the value in the '{nameof(SerializedMember.fields)}' or '{nameof(SerializedMember.props)}' property instead.");
+            try
+            {
+                obj = value
+                    .ToGameObjectRef(
+                        reflector: reflector,
+                        suppressException: false,
+                        depth: depth,
+                        stringBuilder: stringBuilder,
+                        logger: logger)
+                    .FindGameObject();
+                return true;
+            }
+            catch (Exception ex)
+            {
+                if (logger?.IsEnabled(LogLevel.Error) == true)
+                    logger.LogError(ex, $"{padding}[Error] Failed to deserialize value for type '{type.GetTypeName(pretty: false)}'. Convertor: {GetType().GetTypeShortName()}. Exception: {ex.Message}");
+
+                if (stringBuilder != null)
+                    stringBuilder.AppendLine($"{padding}[Error] Failed to set value for type '{type.GetTypeName(pretty: false)}'. Convertor: {GetType().GetTypeShortName()}. Exception: {ex.Message}");
 
-            return false;
+                return false;
+            }
         }
 
         protected override bool TryPopulateField(
@@ -167,6 +185,9 @@ protected override bool TryPopulateField(
             BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance,
             ILogger? logger = null)
         {
+            if (logger?.IsEnabled(LogLevel.Information) == true)
+                logger.LogInformation($"[{GetType().GetTypeShortName()}] TryPopulateField called for obj type: {obj?.GetType().GetTypeName(pretty: false)}, field: {fieldValue.name}");
+
             var padding = StringUtils.GetPadding(depth);
             var go = obj as UnityEngine.GameObject;
             if (go == null)