From e0de6744e2aebd74ae133292ed9813c0afb545f3 Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Tue, 14 Nov 2023 11:22:41 +0100
Subject: [PATCH] Add better errors logging to BT nodes in case of issues

---
 Source/Engine/AI/BehaviorTree.cs       | 16 +++++++++++-----
 Source/Engine/AI/BehaviorTreeNodes.cpp |  2 ++
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/Source/Engine/AI/BehaviorTree.cs b/Source/Engine/AI/BehaviorTree.cs
index 699c72976..a1c863e6b 100644
--- a/Source/Engine/AI/BehaviorTree.cs
+++ b/Source/Engine/AI/BehaviorTree.cs
@@ -95,12 +95,16 @@ namespace FlaxEngine
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public ref T GetState<T>(IntPtr memory) where T : struct
         {
-            var ptr = IntPtr.Add(memory, _memoryOffset).ToPointer();
-            var handle = GCHandle.FromIntPtr(Unsafe.Read<IntPtr>(ptr));
+            var ptr = Unsafe.Read<IntPtr>(IntPtr.Add(memory, _memoryOffset).ToPointer());
+#if !BUILD_RELEASE
+            if (ptr == IntPtr.Zero)
+                throw new Exception($"Missing state '{typeof(T).FullName}' for node '{GetType().FullName}'");
+#endif
+            var handle = GCHandle.FromIntPtr(ptr);
             var state = handle.Target;
 #if !BUILD_RELEASE
             if (state == null)
-                throw new NullReferenceException();
+                throw new Exception($"Missing state '{typeof(T).FullName}' for node '{GetType().FullName}'");
 #endif
             return ref Unsafe.Unbox<T>(state);
         }
@@ -111,8 +115,10 @@ namespace FlaxEngine
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void FreeState(IntPtr memory)
         {
-            var ptr = IntPtr.Add(memory, _memoryOffset).ToPointer();
-            var handle = GCHandle.FromIntPtr(Unsafe.Read<IntPtr>(ptr));
+            var ptr = Unsafe.Read<IntPtr>(IntPtr.Add(memory, _memoryOffset).ToPointer());
+            if (ptr == IntPtr.Zero)
+                return;
+            var handle = GCHandle.FromIntPtr(ptr);
             handle.Free();
         }
     }
diff --git a/Source/Engine/AI/BehaviorTreeNodes.cpp b/Source/Engine/AI/BehaviorTreeNodes.cpp
index 4be336b35..fb49a007e 100644
--- a/Source/Engine/AI/BehaviorTreeNodes.cpp
+++ b/Source/Engine/AI/BehaviorTreeNodes.cpp
@@ -85,6 +85,8 @@ BehaviorUpdateResult BehaviorTreeNode::InvokeUpdate(const BehaviorUpdateContext&
         result = BehaviorUpdateResult::Failed;
     else
         result = Update(context);
+    if ((int32)result < 0 ||  (int32)result > (int32)BehaviorUpdateResult::Failed)
+        result = BehaviorUpdateResult::Failed; // Invalid value is a failure
 
     // Post-process result from decorators
     for (BehaviorTreeDecorator* decorator : _decorators)