fix: Unity 2021.3 compat — compile errors, Mono crash, 19 test failures

MCPForUnity/Editor/Helpers/ComponentOps.cs

@@ -748,6 +748,18 @@ internal static bool SetObjectReference(SerializedProperty prop, JToken value, o
                     return AssignObjectReference(prop, resolved, null, out error);
                 }
 
+                // Try as asset GUID (32-char hex string)
+                if (strVal.Length == 32 && IsHexString(strVal))
+                {
+                    string assetPath = AssetDatabase.GUIDToAssetPath(strVal);
+                    if (!string.IsNullOrEmpty(assetPath))
+                    {
+                        var resolved = AssetDatabase.LoadAssetAtPath<UnityEngine.Object>(assetPath);
+                        if (resolved != null)
+                            return AssignObjectReference(prop, resolved, null, out error);
+                    }
+                }
+
                 // Fall back to scene hierarchy lookup by name.
                 return ResolveSceneObjectByName(prop, strVal, null, out error);
             }
@@ -969,6 +981,16 @@ private static long GetSpriteFileId(Sprite sprite)
                 return 0;
             }
         }
+
+        private static bool IsHexString(string str)
+        {
+            foreach (char c in str)
+            {
+                if (!((c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F')))
+                    return false;
+            }
+            return true;
+        }
     }
 }
 

MCPForUnity/Editor/Tools/Profiler/Operations/CounterOps.cs

@@ -111,7 +111,11 @@ void Tick()
 
         private static readonly string[] ValidCategories = new[]
         {
-            "Render", "Scripts", "Memory", "Physics", "Physics2D", "Animation",
+            "Render", "Scripts", "Memory", "Physics",
+#if UNITY_2022_2_OR_NEWER
+            "Physics2D",
+#endif
+            "Animation",
             "Audio", "Lighting", "Network", "Gui", "UI", "Ai", "Video",
             "Loading", "Input", "Vr", "Internal", "Particles", "FileIO", "VirtualTexturing"
         };
@@ -125,7 +129,9 @@ void Tick()
                 case "scripts": return ProfilerCategory.Scripts;
                 case "memory": return ProfilerCategory.Memory;
                 case "physics": return ProfilerCategory.Physics;
+#if UNITY_2022_2_OR_NEWER
                 case "physics2d": return ProfilerCategory.Physics2D;
+#endif
                 case "animation": return ProfilerCategory.Animation;
                 case "audio": return ProfilerCategory.Audio;
                 case "lighting": return ProfilerCategory.Lighting;

MCPForUnity/Editor/Tools/Profiler/Operations/FrameTimingOps.cs

@@ -8,13 +8,15 @@ internal static class FrameTimingOps
     {
         internal static object GetFrameTiming(JObject @params)
         {
+#if UNITY_2022_2_OR_NEWER
             if (!FrameTimingManager.IsFeatureEnabled())
             {
                 return new ErrorResponse(
                     "Frame Timing Stats is not enabled. "
                     + "Enable it in Project Settings > Player > Other Settings > 'Frame Timing Stats', "
                     + "or use a Development Build (always enabled).");
             }
+#endif
 
             FrameTimingManager.CaptureFrameTimings();
             var timings = new FrameTiming[1];
@@ -33,12 +35,16 @@ internal static object GetFrameTiming(JObject @params)
             {
                 available = true,
                 cpu_frame_time_ms = t.cpuFrameTime,
+#if UNITY_2022_2_OR_NEWER
                 cpu_main_thread_frame_time_ms = t.cpuMainThreadFrameTime,
                 cpu_main_thread_present_wait_time_ms = t.cpuMainThreadPresentWaitTime,
                 cpu_render_thread_frame_time_ms = t.cpuRenderThreadFrameTime,
+#endif
                 gpu_frame_time_ms = t.gpuFrameTime,
+#if UNITY_2022_2_OR_NEWER
                 frame_start_timestamp = t.frameStartTimestamp,
                 first_submit_timestamp = t.firstSubmitTimestamp,
+#endif
                 cpu_time_present_called = t.cpuTimePresentCalled,
                 cpu_time_frame_complete = t.cpuTimeFrameComplete,
                 height_scale = t.heightScale,

MCPForUnity/Editor/Tools/UnityReflect.cs

@@ -170,6 +170,23 @@ private static object GetTypeInfo(ToolParams p)
                 });
             }
 
+            // Open generic type definitions (e.g. List<T>) segfault Mono on Unity 2021.3
+            // in mono_metadata_generic_param_equal_internal when any member reflection is
+            // performed. Return minimal info using only safe property accesses.
+            if (type.IsGenericTypeDefinition)
+            {
+                return new SuccessResponse($"Type info for '{type.Name}'.", new
+                {
+                    found = true,
+                    name = type.Name,
+                    full_name = type.FullName,
+                    @namespace = type.Namespace,
+                    assembly = type.Assembly.GetName().Name,
+                    is_generic_type_definition = true,
+                    hint = "Open generic type — consult docs for member details."
+                });
+            }
+
             var flags = BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static | BindingFlags.DeclaredOnly;
 
             var methods = type.GetMethods(flags)
@@ -272,6 +289,19 @@ private static object GetMemberInfo(ToolParams p)
                 });
             }
 
+            if (type.IsGenericTypeDefinition)
+            {
+                return new SuccessResponse(
+                    $"Open generic type '{type.Name}' — consult docs for member details.", new
+                    {
+                        found = false,
+                        type_name = type.FullName,
+                        member_name = memberName,
+                        is_generic_type_definition = true,
+                        hint = "Open generic type — consult docs for member details."
+                    });
+            }
+
             // Use flags without DeclaredOnly to find inherited members
             var flags = BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static;
 

Server/tests/test_cli_commands_characterization.py

@@ -807,7 +807,7 @@ def test_prefab_workflow_open_modify_save(self, runner, mock_config):
                 assert result.exit_code == 0
 
                 # Save
-                result = runner.invoke(prefab, ["save", "--force"])
+                result = runner.invoke(prefab, ["save"])
                 assert result.exit_code == 0
 
                 # Close

TestProjects/UnityMCPTests/Assets/Tests/EditMode/Tools/ManageGraphicsTests.cs

@@ -15,6 +15,7 @@ public class ManageGraphicsTests
         private const string TempRoot = "Assets/Temp/ManageGraphicsTests";
         private bool _hasVolumeSystem;
         private bool _hasURP;
+        private bool _hasHDRP;
 
         [SetUp]
         public void SetUp()
@@ -28,6 +29,7 @@ public void SetUp()
                 var data = pingResult["data"];
                 _hasVolumeSystem = data?.Value<bool>("hasVolumeSystem") ?? false;
                 _hasURP = data?.Value<bool>("hasURP") ?? false;
+                _hasHDRP = data?.Value<bool>("hasHDRP") ?? false;
             }
         }
 
@@ -72,7 +74,7 @@ public void HandleCommand_MissingAction_ReturnsError()
         {
             var result = ToJObject(ManageGraphics.HandleCommand(new JObject()));
             Assert.IsFalse(result.Value<bool>("success"));
-            Assert.That(result["message"].ToString(), Does.Contain("action"));
+            Assert.That(result["error"].ToString(), Does.Contain("action"));
         }
 
         [Test]
@@ -81,7 +83,7 @@ public void HandleCommand_UnknownAction_ReturnsError()
             var result = ToJObject(ManageGraphics.HandleCommand(
                 new JObject { ["action"] = "bogus_action" }));
             Assert.IsFalse(result.Value<bool>("success"));
-            Assert.That(result["message"].ToString(), Does.Contain("Unknown action"));
+            Assert.That(result["error"].ToString(), Does.Contain("Unknown action"));
         }
 
         [Test]
@@ -539,7 +541,7 @@ public void BakeSetProbePositions_WrongComponent_ReturnsError()
                 ["positions"] = new JArray { new JArray(0, 0, 0) }
             }));
             Assert.IsFalse(result.Value<bool>("success"));
-            Assert.That(result["message"].ToString(), Does.Contain("LightProbeGroup"));
+            Assert.That(result["error"].ToString(), Does.Contain("LightProbeGroup"));
         }
 
         // =====================================================================
@@ -598,7 +600,7 @@ public void StatsSetSceneDebug_InvalidMode_ReturnsError()
                 ["mode"] = "InvalidMode"
             }));
             Assert.IsFalse(result.Value<bool>("success"));
-            Assert.That(result["message"].ToString(), Does.Contain("Valid:"));
+            Assert.That(result["error"].ToString(), Does.Contain("Valid:"));
         }
 
         // =====================================================================
@@ -618,6 +620,7 @@ public void PipelineGetInfo_ReturnsPipelineName()
         [Test]
         public void PipelineGetSettings_ReturnsSettings()
         {
+            Assume.That(_hasURP || _hasHDRP, "Built-in pipeline has no settings asset — skipping.");
             var result = ToJObject(ManageGraphics.HandleCommand(
                 new JObject { ["action"] = "pipeline_get_settings" }));
             Assert.IsTrue(result.Value<bool>("success"), result.ToString());
@@ -635,7 +638,7 @@ public void PipelineSetQuality_InvalidLevel_ReturnsError()
                 ["level"] = "NonExistentLevel"
             }));
             Assert.IsFalse(result.Value<bool>("success"));
-            Assert.That(result["message"].ToString(), Does.Contain("Available:"));
+            Assert.That(result["error"].ToString(), Does.Contain("Available:"));
         }
 
         // =====================================================================

TestProjects/UnityMCPTests/Assets/Tests/EditMode/Tools/ManagePhysicsTests.cs

@@ -768,16 +768,17 @@ public void SetCollisionMatrix_MissingParams_ReturnsError()
         [Test]
         public void Raycast_HitsCollider()
         {
+            // Use an offset origin/direction to avoid hitting unrelated scene objects
             var go = new GameObject("PhysTest_RayTarget");
-            go.transform.position = new Vector3(0, 0, 5);
+            go.transform.position = new Vector3(500, 500, 5);
             var col = go.AddComponent<BoxCollider>();
             col.size = new Vector3(10, 10, 1);
             UnityEngine.Physics.SyncTransforms();
 
             var result = ToJObject(ManagePhysics.HandleCommand(new JObject
             {
                 ["action"] = "raycast",
-                ["origin"] = new JArray(0, 0, 0),
+                ["origin"] = new JArray(500, 500, 0),
                 ["direction"] = new JArray(0, 0, 1),
                 ["max_distance"] = 100
             }));

TestProjects/UnityMCPTests/Assets/Tests/EditMode/Tools/ManageProBuilderTests.cs

@@ -53,8 +53,8 @@ public void HandleCommand_UnknownAction_ReturnsError()
             var result = ToJObject(ManageProBuilder.HandleCommand(paramsObj));
 
             Assert.IsFalse(result.Value<bool>("success"), result.ToString());
-            Assert.That(result["error"]?.ToString() ?? result["message"]?.ToString(),
-                Does.Contain("Unknown action"));
+            var errorMsg = result["error"]?.ToString() ?? result["message"]?.ToString();
+            Assert.That(errorMsg, Does.Contain("Unknown action").Or.Contain("not installed"));
         }
 
         [Test]

TestProjects/UnityMCPTests/Assets/Tests/EditMode/Tools/ManageSceneHierarchyPagingTests.cs

@@ -115,7 +115,7 @@ public void Screenshot_SceneViewRejectsSupersizeAboveOne()
             var response = raw as JObject ?? JObject.FromObject(raw);
 
             Assert.IsFalse(response.Value<bool>("success"), response.ToString());
-            StringAssert.Contains("does not support super_size above 1", response.Value<string>("message"));
+            StringAssert.Contains("does not support super_size above 1", response.Value<string>("error"));
         }
 
         [Test]
@@ -182,7 +182,7 @@ public void Screenshot_ViewTargetAcceptedForGameView()
 
             // Should attempt positioned capture and fail to resolve the GO — not reject the param
             Assert.IsFalse(response.Value<bool>("success"), response.ToString());
-            StringAssert.Contains("not found", response.Value<string>("message"));
+            StringAssert.Contains("not found", response.Value<string>("error"));
         }
 
         [Test]

TestProjects/UnityMCPTests/Assets/Tests/EditMode/Tools/ManageSceneMultiSceneTests.cs

@@ -78,7 +78,7 @@ public void ModifyBuildSettings_RedirectsToManageBuild()
             var result = ManageScene.HandleCommand(p);
             var r = result as JObject ?? JObject.FromObject(result);
             Assert.IsFalse(r.Value<bool>("success"));
-            Assert.IsTrue(r.Value<string>("message").Contains("manage_build"));
+            Assert.IsTrue(r.Value<string>("error").Contains("manage_build"));
         }
 
         [Test]