Fix crash when using and saving scene with Visual Script object instance which asset was deleted

Source/Engine/Content/Assets/VisualScript.cpp

@@ -1522,12 +1522,16 @@ void VisualScript::unload(bool isReloading)
     if (_scriptingTypeHandle)
     {
         VisualScriptingBinaryModule::Locker.Lock();
-        auto& type = VisualScriptingModule.Types[_scriptingTypeHandle.TypeIndex];
+        ScriptingType& type = VisualScriptingModule.Types[_scriptingTypeHandle.TypeIndex];
         if (type.Script.DefaultInstance)
         {
             Delete(type.Script.DefaultInstance);
             type.Script.DefaultInstance = nullptr;
         }
+        char* typeName = (char*)Allocator::Allocate(sizeof(_typenameChars));
+        Platform::MemoryCopy(typeName, _typenameChars, sizeof(_typenameChars));
+        ((StringAnsiView&)type.Fullname) = StringAnsiView(typeName, 32);
+        VisualScriptingModule._unloadedScriptTypeNames.Add(typeName);
         VisualScriptingModule.TypeNameToTypeIndex.RemoveValue(_scriptingTypeHandle.TypeIndex);
         VisualScriptingModule.Scripts[_scriptingTypeHandle.TypeIndex] = nullptr;
         _scriptingTypeHandleCached = _scriptingTypeHandle;
@@ -1653,6 +1657,8 @@ VisualScriptingBinaryModule::VisualScriptingBinaryModule()
 ScriptingObject* VisualScriptingBinaryModule::VisualScriptObjectSpawn(const ScriptingObjectSpawnParams& params)
 {
     // Create native object (base type can be C++ or C#)
+    if (params.Type.Module == nullptr)
+        return nullptr;
     ScriptingType& visualScriptType = (ScriptingType&)params.Type.GetType();
     ScriptingTypeHandle baseTypeHandle = visualScriptType.GetBaseType();
     const ScriptingType* baseTypePtr = &baseTypeHandle.GetType();
@@ -1663,9 +1669,7 @@ ScriptingObject* VisualScriptingBinaryModule::VisualScriptObjectSpawn(const Scri
     }
     ScriptingObject* object = baseTypePtr->Script.Spawn(params);
     if (!object)
-    {
         return nullptr;
-    }
 
     // Beware! Hacking vtables incoming! Undefined behaviors exploits! Low-level programming!
     visualScriptType.HackObjectVTable(object, baseTypeHandle, 1);
@@ -2060,6 +2064,11 @@ void VisualScriptingBinaryModule::Destroy(bool isReloading)
         return;
 
     BinaryModule::Destroy(isReloading);
+
+    // Free cached script typenames table
+    for (char* str : _unloadedScriptTypeNames)
+        Allocator::Free(str);
+    _unloadedScriptTypeNames.Clear();
 }
 
 ScriptingTypeHandle VisualScript::GetScriptingType()

Source/Engine/Content/Assets/VisualScript.h

@@ -305,6 +305,7 @@ class FLAXENGINE_API VisualScriptingBinaryModule : public BinaryModule
     friend VisualScript;
 private:
     StringAnsi _name;
+    Array<char*> _unloadedScriptTypeNames;
 
 public:
     /// <summary>

Source/Engine/Scripting/BinaryModule.h

@@ -118,7 +118,7 @@ public:
     /// <summary>
     /// Tries to find a method in a given scripting type by the method name and parameters count.
     /// </summary>
-    /// <remarks>If the the type contains more than one method of the given name and parameters count the returned value can be non-deterministic (one of the matching methods).</remarks>
+    /// <remarks>If the type contains more than one method of the given name and parameters count the returned value can be non-deterministic (one of the matching methods).</remarks>
     /// <param name="typeHandle">The type to find method inside it.</param>
     /// <param name="name">The method name.</param>
     /// <param name="numParams">The method parameters count.</param>
@@ -182,7 +182,7 @@ public:
     /// Gets the value of a given scripting field.
     /// </summary>
     /// <param name="field">The field.</param>
-    /// <param name="instance">The object instance to get it's member field. Unused for static fields.</param>
+    /// <param name="instance">The object instance to get its member field. Unused for static fields.</param>
     /// <param name="result">The output field value.</param>
     /// <returns>True if failed, otherwise false.</returns>
     virtual bool GetFieldValue(void* field, const Variant& instance, Variant& result)
@@ -194,7 +194,7 @@ public:
     /// Sets the value of a given scripting field.
     /// </summary>
     /// <param name="field">The field.</param>
-    /// <param name="instance">The object instance to set it's member field. Unused for static fields.</param>
+    /// <param name="instance">The object instance to set its member field. Unused for static fields.</param>
     /// <param name="value">The field value to assign.</param>
     /// <returns>True if failed, otherwise false.</returns>
     virtual bool SetFieldValue(void* field, const Variant& instance, Variant& value)
@@ -242,7 +242,7 @@ public:
     /// <summary>
     /// Unloads the module (native library and C# assembly and any other scripting data). Unregisters the module.
     /// </summary>
-    /// <param name="isReloading">If true module is during reloading and should force release the runtime data. Used for C# assembly to cleanup it's runtime data in Mono (or other scripting runtime).</param>
+    /// <param name="isReloading">If true module is during reloading and should force release the runtime data. Used for C# assembly to clean up it's runtime data in Mono (or other scripting runtime).</param>
     virtual void Destroy(bool isReloading);
 };