Issue allocating NativeQueue when NativeList are scheduled to dispose

I noticed recently that the native containers have received schedulable Dispose function (which is great!) so I've been using them but noticed that every once in a while I'll get an error when trying to use a newly allocated container.

Below is a constructed example that almost immediately hits the error (on my computer at least).

Code (CSharp):

1. using Unity.Collections;
2. using Unity.Jobs;
3. using UnityEngine;
4.  
5. public class TestParallelWriterDealloc : MonoBehaviour
6. {
7.     private struct TestJob : IJobParallelFor
8.     {
9.         public NativeQueue<int>.ParallelWriter writer;
10.        
11.         public void Execute(int index)
12.         {
13.             writer.Enqueue(index);
14.         }
15.     }
16.  
17.     private struct ListJob : IJob
18.     {
19.         public NativeList<int> list;
20.  
21.         public void Execute()
22.         {
23.             for (int i = 0; i < 100; i++)
24.             {
25.                 list.Add(i);;
26.             }
27.         }
28.     }
29.    
30.     private void Update()
31.     {
32.         JobHandle handle = default;
33.        
34.         NativeList<int> list1 = new NativeList<int>(100, Allocator.TempJob);
35.            
36.         ListJob listJob1 = new ListJob();
37.         listJob1.list = list1;
38.  
39.         JobHandle listHandle1 = listJob1.Schedule(handle);
40.  
41.         NativeList<int> list2 = new NativeList<int>(100, Allocator.TempJob);
42.  
43.         ListJob listJob2 = new ListJob();
44.         listJob2.list = list2;
45.  
46.         JobHandle listHandle2 = listJob2.Schedule(handle);
47.  
48.         handle = JobHandle.CombineDependencies(listHandle1, listHandle2);
49.         handle = JobHandle.CombineDependencies(list1.Dispose(handle), list2.Dispose(handle));
50.        
51.         // Forcing a complete here will fix the issue
52.         //handle.Complete();
53.            
54.         NativeQueue<int> queue = new NativeQueue<int>(Allocator.TempJob);
55.            
56.         TestJob job = new TestJob();
57.         job.writer = queue.AsParallelWriter();
58.        
59.         // The job fails with the following exception
60.         // InvalidOperationException: The NativeContainer TestJob.writer has been deallocated. All containers must be valid when scheduling a job.
61.         handle = job.Schedule(43, 16, handle);
62.         handle = queue.Dispose(handle);
63.        
64.         handle.Complete();
65.     }
66. }

This is close to what I'm doing in the actual code. I have some jobs using two lists in parallel then disposing them. Afterwards (on the same handle) I'm allocating a queue and assigning its ParallelWriter to a new job. That job failed with the InvalidOperationException.

As noted in the code above if I do a handle.Complete() after scheduling the two dispose then there isn't any issues.

As far as I can tell I'm following patterns just fine. Is this a bug?

 

Posted code works fine without any errors, are you sure this is problem place?

Code (CSharp):

1.  
2. using System.Collections;
3. using System.Collections.Generic;
4. using Unity.Collections;
5. using Unity.Jobs;
6. using UnityEngine;
7.  
8. public class TestJob : MonoBehaviour
9. {
10.     private struct OneJob : IJobParallelFor
11.     {
12.         public NativeQueue<int>.ParallelWriter writer;
13.  
14.         public void Execute(int index)
15.         {
16.             writer.Enqueue(index);
17.         }
18.     }
19.  
20.     private struct ListJob : IJob
21.     {
22.         public NativeList<int> list;
23.  
24.         public void Execute()
25.         {
26.             for (int i = 0; i < 100; i++)
27.             {
28.                 list.Add(i);
29.                 ;
30.             }
31.  
32.             Debug.Log("Inside List Job");
33.         }
34.     }
35.  
36.     private void Update()
37.     {
38.         JobHandle handle = default;
39.  
40.         NativeList<int> list1 = new NativeList<int>(100, Allocator.TempJob);
41.  
42.         ListJob listJob1 = new ListJob();
43.         listJob1.list = list1;
44.  
45.         JobHandle listHandle1 = listJob1.Schedule(handle);
46.  
47.         NativeList<int> list2 = new NativeList<int>(100, Allocator.TempJob);
48.  
49.         ListJob listJob2 = new ListJob();
50.         listJob2.list = list2;
51.  
52.         JobHandle listHandle2 = listJob2.Schedule(handle);
53.  
54.         handle = JobHandle.CombineDependencies(listHandle1,           listHandle2);
55.         handle = JobHandle.CombineDependencies(list1.Dispose(handle), list2.Dispose(handle));
56.  
57.         NativeQueue<int> queue = new NativeQueue<int>(Allocator.TempJob);
58.  
59.         OneJob job = new OneJob();
60.         job.writer = queue.AsParallelWriter();
61.  
62.         handle = job.Schedule(43, 16, handle);
63.         handle = queue.Dispose(handle);
64.  
65.         handle.Complete();
66.  
67.         Debug.Log("Update End");
68.     }
69. }
70.  

 

Unfortunately I'm not quite so lucky I created a new project and updated 2019.2.7f2 and the problem remains. I used your (slightly) modified script exactly.



I had another teammate try it and they hit the issue as well.

The blank project has just 0.1.1 Collections package installed.

 

I’m on 2019.3

 

Upgrading the blank project to 2019.3 has resolved the issue. I'll move the actual project over and see that resolves it as well.

Thanks!