Issue report: Fixed Array in entity are disposed when destroying other entities

the error "InvalidOperationException: The NativeArray has been deallocated, it is not allowed to access it" will be throw when running the following code and calling Test() function.

Code (CSharp):

1. using UnityEngine;
2. using Unity.Collections;
3. using Unity.Entities;
4.  
5. public class FixedArrayTest : MonoBehaviour
6. {
7.     NativeArray<Entity> entities;
8.  
9.     EntityManager entityManager;
10.  
11.     struct EntityHolder
12.     {
13.         public Entity En;
14.     }
15.     // Use this for initialization
16.     void Start()
17.     {
18.         entityManager = World.Active.GetOrCreateManager<EntityManager>();
19.  
20.         entities = new NativeArray<Entity>(100, Allocator.Persistent, NativeArrayOptions.UninitializedMemory);
21.         entityManager.Instantiate(entityManager.CreateEntity(ComponentType.FixedArray(typeof(EntityHolder), 2)), entities);
22.  
23.  
24.         var array0 = new NativeArray<Entity>(100, Allocator.Temp, NativeArrayOptions.UninitializedMemory);
25.         entityManager.Instantiate(entityManager.CreateEntity(), array0);
26.  
27.         var array1 = new NativeArray<Entity>(100, Allocator.Temp, NativeArrayOptions.UninitializedMemory);
28.         entityManager.Instantiate(entityManager.CreateEntity(), array1);
29.  
30.         for (int i = 0; i < entities.Length; i++)
31.         {
32.             var fixedArray = entityManager.GetFixedArray<EntityHolder>(entities[i]);
33.             fixedArray[0] = new EntityHolder { En = array0[i] };
34.             fixedArray[1] = new EntityHolder { En = array1[i] };
35.         }
36.         array0.Dispose();
37.         array1.Dispose();
38.     }
39.  
40.    
41.     void Test()
42.     {
43.         for (int i = 0; i < entities.Length; i++)
44.         {
45.             var array = entityManager.GetFixedArray<EntityHolder>(entities[i]);
46.  
47.             entityManager.DestroyEntity(array[0].En);
48.             entityManager.DestroyEntity(array[1].En);
49.  
50.         }
51.     }
52. }

with the line " entityManager.DestroyEntity(array[1].En);" being pointed as the source of the error.

Do note that the entity hosting the array is not touched.

also, if I have only "entityManager.DestroyEntity(array[0].En);" without accessing the second element in the array, it work without error.

 

When you create/destroy an entity the component chunks and entity array are rebuilt. So what you are seeing is expected.

See the section towards the bottom on EntityCommandBuffer.
https://github.com/Unity-Technologi...master/Documentation/content/ecs_in_detail.md