From af5f3cbd95e8c46762fac91cf8632f4b1de717ed Mon Sep 17 00:00:00 2001
From: Chandler Cox <mr.chandlercox@gmail.com>
Date: Thu, 15 Dec 2022 08:18:09 -0600
Subject: [PATCH 1/3] Return null if type is abstract but trying to be added as
 an actor or script

---
 Source/Engine/Level/Actor.cs | 15 +++++++++++++++
 Source/Engine/Level/Actor.h  |  4 ++++
 2 files changed, 19 insertions(+)

diff --git a/Source/Engine/Level/Actor.cs b/Source/Engine/Level/Actor.cs
index 936d38565..cd774fca6 100644
--- a/Source/Engine/Level/Actor.cs
+++ b/Source/Engine/Level/Actor.cs
@@ -123,6 +123,9 @@ namespace FlaxEngine
         /// <returns>The child actor.</returns>
         public Actor AddChild(Type type)
         {
+            if (type.IsAbstract)
+                return null;
+            
             var result = (Actor)New(type);
             result.SetParent(this, false, false);
             return result;
@@ -135,6 +138,9 @@ namespace FlaxEngine
         /// <returns>The child actor.</returns>
         public T AddChild<T>() where T : Actor
         {
+            if (typeof(T).IsAbstract)
+                return null;
+
             var result = New<T>();
             result.SetParent(this, false, false);
             return result;
@@ -172,6 +178,9 @@ namespace FlaxEngine
             var result = GetChild<T>();
             if (result == null)
             {
+                if (typeof(T).IsAbstract)
+                    return null;
+                
                 result = New<T>();
                 result.SetParent(this, false, false);
             }
@@ -185,6 +194,9 @@ namespace FlaxEngine
         /// <returns>The created script instance, null otherwise.</returns>
         public Script AddScript(Type type)
         {
+            if (type.IsAbstract)
+                return null;
+            
             var script = (Script)New(type);
             script.Parent = this;
             return script;
@@ -197,6 +209,9 @@ namespace FlaxEngine
         /// <returns>The created script instance, null otherwise.</returns>
         public T AddScript<T>() where T : Script
         {
+            if (typeof(T).IsAbstract)
+                return null;
+            
             var script = New<T>();
             script.Parent = this;
             return script;
diff --git a/Source/Engine/Level/Actor.h b/Source/Engine/Level/Actor.h
index e9ad7793c..e108b0756 100644
--- a/Source/Engine/Level/Actor.h
+++ b/Source/Engine/Level/Actor.h
@@ -227,6 +227,10 @@ public:
         T* result = (T*)GetChild(T::GetStaticClass());
         if (!result)
         {
+            const MClass* type = T::GetStaticClass();
+            if (type->IsAbstract())
+                return nullptr;
+
             result = New<T>();
             result->SetParent(this, false, false);
         }

From c3f23d13902581ad5ae7c8268660e72c1f453393 Mon Sep 17 00:00:00 2001
From: Chandler Cox <mr.chandlercox@gmail.com>
Date: Thu, 15 Dec 2022 08:49:52 -0600
Subject: [PATCH 2/3] Added abstract check to spawning actor

---
 Source/Engine/Level/Level.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Source/Engine/Level/Level.cpp b/Source/Engine/Level/Level.cpp
index 98ad5a694..485b1a3b6 100644
--- a/Source/Engine/Level/Level.cpp
+++ b/Source/Engine/Level/Level.cpp
@@ -177,6 +177,12 @@ bool LevelImpl::spawnActor(Actor* actor, Actor* parent)
         return true;
     }
 
+    if (actor->GetType().ManagedClass->IsAbstract())
+    {
+        Log::Exception(TEXT("Cannot spawn abstract actor type."));
+        return true;
+    }
+
     if (actor->Is<Scene>())
     {
         // Spawn scene

From 66771775341b94d90080da6c70f4cc233d39032e Mon Sep 17 00:00:00 2001
From: Chandler Cox <mr.chandlercox@gmail.com>
Date: Thu, 15 Dec 2022 08:52:37 -0600
Subject: [PATCH 3/3] Removed variable MClass

---
 Source/Engine/Level/Actor.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Source/Engine/Level/Actor.h b/Source/Engine/Level/Actor.h
index e108b0756..ec52a8c74 100644
--- a/Source/Engine/Level/Actor.h
+++ b/Source/Engine/Level/Actor.h
@@ -227,8 +227,7 @@ public:
         T* result = (T*)GetChild(T::GetStaticClass());
         if (!result)
         {
-            const MClass* type = T::GetStaticClass();
-            if (type->IsAbstract())
+            if (T::GetStaticClass()->IsAbstract())
                 return nullptr;
 
             result = New<T>();