Issue: AsyncOperationBase<TObject>.Task Can't Finish

This was tested with addressable 0.7.4 and unity 2019.1.0f2.

The bug show in the following comment.

Code (CSharp):

1.      
2.         internal System.Threading.Tasks.Task<TObject> Task
3.         {
4.             get
5.             {
6.                 return System.Threading.Tasks.Task.Factory.StartNew(o =>
7.                 {
8.                     // Sometimes the following code is called after the function
9.                     // InvokeCompletionEvent() call.
10.                     // So the task that returned become unuseful.
11.                     var asyncOperation = o as AsyncOperationBase<TObject>;
12.                     // m_waitHandle only initialize here.
13.                     asyncOperation.WaitHandle.WaitOne();
14.                     return asyncOperation.Result;
15.                 }, this);
16.             }
17.         }
18.  
19. ..................................................................................................................................
20.  
21.         internal void InvokeCompletionEvent()
22.         {
23.             if (m_CompletedAction != null)
24.             {
25.                 m_CompletedAction.Invoke(new AsyncOperationHandle(this));
26.                 m_CompletedAction.Clear();
27.             }
28.  
29.             if (m_CompletedActionT != null)
30.             {
31.                 m_CompletedActionT.Invoke(new AsyncOperationHandle<TObject>(this));
32.                 m_CompletedActionT.Clear();
33.             }
34.             if (m_waitHandle != null)
35.                 m_waitHandle.Set();
36.  
37.             m_InDeferredCallbackQueue = false;
38.         }

And this is my fix

Code (CSharp):

1.        
2.         internal System.Threading.Tasks.Task<TObject> Task
3.         {
4.             get
5.             {
6.                 var bugFix = WaitHandle;
7.                 return System.Threading.Tasks.Task.Factory.StartNew(o =>
8.                 {
9.                     var asyncOperation = o as AsyncOperationBase<TObject>;
10.                     // asyncOperation.WaitHandle.WaitOne();
11.                     bugFix.WaitOne();
12.                     return asyncOperation.Result;
13.                 }, this);
14.             }
15.         }

 

+1

also, spawning a new thread only for waiting on the wait handle is bad.
a

TaskCompletionSource<TObject>

should be used here (or better yet, make the async operation itself awaitable)

 

This issue is still present in 0.8.6-preview and has caused us a lot of headache. The fix provided works.

 

Hello, same here I was running into this major issue and the fix works, but it's still just a workaround.
What's the ETA for a release included a proper fix?
Thanks.

Damien

 

when await Task after AsyncOperation is completed, can not finish handle.
this issue is preset in 1.1.4-preview.

this is my fix.

implementation of custom Awaiter made the Task property unnecessary

Code (CSharp):

1.  
2.  
3. // Usage:    
4. // try {
5. //   Sprite result = await rm.ProvideResource<Sprite>(location);
6. // } catch (Exception e) {
7. //    Debug.LogException(e);
8. // }
9.  
10. public struct AsyncOperationHandleAwaiter<TObject> : ICriticalNotifyCompletion
11.     {
12.         private AsyncOperationHandle<TObject> handle;
13.         private Action continuation;
14.  
15.         public AsyncOperationHandleAwaiter(AsyncOperationHandle<TObject> handle) : this()
16.         {
17.             this.handle = handle;
18.         }
19.  
20.         public bool IsCompleted {
21.             get { return handle.IsDone; }
22.         }
23.  
24.         public void OnCompleted(Action continuation)
25.         {
26.             UnsafeOnCompleted(continuation);
27.         }
28.  
29.         public void UnsafeOnCompleted(Action continuation)
30.         {
31.             if (this.continuation != null)
32.             {
33.                 throw new InvalidOperationException("continuation is already registered.");
34.             }
35.  
36.             if (IsCompleted)
37.             {
38.                 continuation();
39.             }
40.             else
41.             {
42.                 this.continuation = continuation;
43.                 handle.Completed += OnHandleOnCompleted;
44.             }
45.         }
46.  
47.         void OnHandleOnCompleted(AsyncOperationHandle<TObject> _)
48.         {
49.             if (continuation != null)
50.             {
51.                 continuation();
52.                 continuation = null;
53.             }
54.         }
55.  
56.         public TObject GetResult()
57.         {
58.             if (handle.Status == AsyncOperationStatus.Succeeded)
59.             {
60.                 return handle.Result;
61.             }
62.             else
63.             {
64.                 throw handle.OperationException;
65.             }
66.         }
67.     }
68.  
69.     public static class AsyncOperationHandleExtensions
70.     {
71.         public static AsyncOperationHandleAwaiter<TObject> GetAwaiter<TObject>(this AsyncOperationHandle<TObject> handle)
72.         {
73.             return new AsyncOperationHandleAwaiter<TObject>(handle);
74.         }
75.     }
76.