DestroyEntity with group filter causes Exception in preview 23

I just came across this new exception when switched to Entities preview 23.

Spoiler: Exception

NullReferenceException: Object reference not set to an instance of an object
Unity.Entities.EntityDataManager.RequiresBuildingResidueSharedComponentIndices (Unity.Entities.Archetype* srcArchetype, Unity.Entities.Archetype* dstArchetype) (at Library/PackageCache/com.unity.entities@0.0.12-preview.23/Unity.Entities/EntityDataManager.cs:1529)
Unity.Entities.EntityDataManager.RemoveEntitiesInChunkWithSystemState (Unity.Entities.Chunk* chunk, Unity.Entities.ArchetypeManager archetypeManager, Unity.Entities.SharedComponentDataManager sharedComponentDataManager) (at Library/PackageCache/com.unity.entities@0.0.12-preview.23/Unity.Entities/EntityDataManager.cs:1133)
Unity.Entities.EntityDataManager.DeleteChunks (Unity.Collections.NativeArray`1[T] chunks, Unity.Entities.EntityDataManager* manager, Unity.Entities.ArchetypeManager archetypeManager, Unity.Entities.SharedComponentDataManager sharedComponentDataManager) (at Library/PackageCache/com.unity.entities@0.0.12-preview.23/Unity.Entities/EntityDataManager.cs:1117)
Unity.Entities.EntityManager.DestroyEntity (Unity.Entities.ComponentGroup componentGroupFilter) (at Library/PackageCache/com.unity.entities@0.0.12-preview.23/Unity.Entities/EntityManager.cs:391)
TestSystem.OnUpdate () (at Assets/TestSystem.cs:15)
Unity.Entities.ComponentSystem.InternalUpdate () (at Library/PackageCache/com.unity.entities@0.0.12-preview.23/Unity.Entities/ComponentSystem.cs:464)
Unity.Entities.ScriptBehaviourManager.Update () (at Library/PackageCache/com.unity.entities@0.0.12-preview.23/Unity.Entities/ScriptBehaviourManager.cs:83)
Unity.Entities.ScriptBehaviourUpdateOrder+DummyDelagateWrapper.TriggerUpdate () (at Library/PackageCache/com.unity.entities@0.0.12-preview.23/Unity.Entities/ScriptBehaviourUpdateOrder.cs:706)

Here is a simple code that illustrates it.

Code (CSharp):

1. public struct TestComponent : IComponentData { }
2.  
3. public class TestSystem : ComponentSystem {
4.   ComponentGroup m_group;
5.  
6.   protected override void OnCreateManager() {
7.     base.OnCreateManager();
8.     m_group = GetComponentGroup(typeof(TestComponent));
9.   }
10.  
11.   protected override void OnUpdate() {
12.     EntityManager.DestroyEntity(m_group);
13.   }
14. }
15.  
16. public class Bootstrap {
17.   [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.AfterSceneLoad)]
18.   public static void InitializeAfterScene() {
19.     var em = World.Active.GetOrCreateManager<EntityManager>();
20.     em.CreateEntity(typeof(TestComponent));
21.   }
22. }

 

I get the same though only after a few runs through.
The code within DestroyEntity(group) has changed to use group.GetAllMatchingChunks() and DeleteChunks() instead of group.getEntityArray().

The problem seems to be here

Code (CSharp):

1. Archetype* archetype = chunk->Archetype->SystemStateResidueArchetype;
2. int numSharedComponents = archetype->NumSharedComponents;    // NullReferenceException here

SystemStateResidueArchetype isn't null but it must refer to some invalid memory or something. I don't have a debugger so can't dig deeper.
For now, I'm just deleting by the Entity array in each chunk.

Code (CSharp):

1. void destroyEntities(ComponentGroup group)
2. {
3.     var chunks = _group.CreateArchetypeChunkArray(Allocator.TempJob);
4.     for (int i = 0; i < chunks.Length; i++)
5.     {
6.         EntityManager.DestroyEntity(chunks[i].GetNativeArray(entityChunkType));
7.     }
8.     chunks.Dispose();
9. }

 

It will be fixed on the next version, for now you can fix manually by initializing SystemStateResidueArchetype:

At ArchetypeManager.cs near line 738

Code (CSharp):

1.             type->MetaChunkArchetype = null;
2.             type->SystemStateResidueArchetype = null; // Add this
3.             type->NumSharedComponents = 0;
4.  

 

Thanks Capyvara, that works.