2.0.24

README.md

@@ -532,6 +532,38 @@ SelectAwaitWithCancellation(Func<T, CancellationToken, UniTask<TR>> selector)
 
 If you want to use the `async` method inside the func, use the `***Await` or `***AwaitWithCancellation`.
 
+How to create async iterator, C# 8.0 supports async iterator(`async yield return`) but it only allows `IAsyncEnumerable<T>` and of course requires C# 8.0. UniTask supports `UniTaskAsyncEnumerable.Create` method to create custom async iterator.
+
+```csharp
+// IAsyncEnumerable, C# 8.0 version of async iterator. ( do not use this style, IAsyncEnumerable is not controled in UniTask).
+public async IAsyncEnumerable<int> MyEveryUpdate([EnumeratorCancellation]CancellationToken cancelationToken)
+{
+    var frameCount = 0;
+    await UniTask.Yield();
+    while (!token.IsCancellationRequested)
+    {
+        yield return frameCount++;
+        await UniTask.Yield();
+    }
+}
+
+// UniTaskAsyncEnumerable.Create and use `await writer.YieldAsync` instead of `yield return`.
+public IUniTaskAsyncEnumerable<int> MyEveryUpdate()
+{
+    // writer(IAsyncWriter<T>) has `YieldAsync(value)` method.
+    return UniTaskAsyncEnumerable.Create<int>(async (writer, token) =>
+    {
+        var frameCount = 0;
+        await UniTask.Yield();
+        while (!token.IsCancellationRequested)
+        {
+            await writer.YieldAsync(frameCount++); // instead of `yield return`
+            await UniTask.Yield();
+        }
+    });
+}
+```
+
 Awaitable Events
 ---
 All uGUI component implements `***AsAsyncEnumerable` to convert asynchronous streams of events.
@@ -812,7 +844,7 @@ After Unity 2019.3.4f1, Unity 2020.1a21, that support path query parameter of gi
 
 or add `"com.cysharp.unitask": "https://github.com/Cysharp/UniTask.git?path=src/UniTask/Assets/Plugins/UniTask"` to `Packages/manifest.json`.
 
-If you want to set a target version, UniTask is using `*.*.*` release tag so you can specify a version like `#2.0.22`. For example `https://github.com/Cysharp/UniTask.git?path=src/UniTask/Assets/Plugins/UniTask#2.0.22`.
+If you want to set a target version, UniTask is using `*.*.*` release tag so you can specify a version like `#2.0.24`. For example `https://github.com/Cysharp/UniTask.git?path=src/UniTask/Assets/Plugins/UniTask#2.0.24`.
 
 ### Install via OpenUPM
 

src/UniTask.NetCoreSandbox/Program.cs

@@ -295,71 +295,25 @@ namespace NetCoreSandbox
             //await new ComparisonBenchmarks().ViaUniTaskT();
             return;
 #endif
-            // await new AllocationCheck().ViaUniTaskVoid();
 
-            var buttonTest = new AsyncReactiveProperty<AsyncUnit>(AsyncUnit.Default);
-
-            buttonTest
-            .Subscribe(async _ =>
+            var e = UniTaskAsyncEnumerable.Create<int>(async (writer, token) =>
             {
-                try
+                for (int i = 0; i < 5; i++)
                 {
-                    await new Foo().MethodFooAsync();
-                }
-                catch (Exception e)
-                {
-                    Console.WriteLine(e.StackTrace);
+                    Console.WriteLine($"Start {i}");
+                    await writer.YieldAsync(i);
+                    Console.WriteLine($"End {i}");
                 }
             });
 
-            buttonTest.Value = AsyncUnit.Default;
-
-
-            // AsyncTest().Forge
-
-            Console.WriteLine("A?");
-            var a = await new ZeroAllocAsyncAwaitInDotNetCore().NanikaAsync(1, 2);
-            Console.WriteLine("RET:" + a);
-            await WhereSelect();
-
-            SynchronizationContext.SetSynchronizationContext(new MySyncContext());
-
-            await Aaa();
-
-
-
-
-            //AsyncTest().Forget();
-
-            // AsyncTest().Forget();
-
-            ThreadPool.SetMinThreads(100, 100);
-
-            //List<UniTask<int>> list = new List<UniTask<int>>();
-            for (int i = 0; i < short.MaxValue; i++)
+            var ee = e.GetAsyncEnumerator();
+            while (await ee.MoveNextAsync())
             {
-                ////    list.Add(AsyncTest());
-                await YieldCore();
+                Console.WriteLine("ForEach " + ee.Current);
             }
-            //await UniTask.WhenAll(list);
-
-            //Console.WriteLine("TOGO");
-
-            //var a = await AsyncTest();
-            //var b = AsyncTest();
-            //var c = AsyncTest();
-            await YieldCore();
-
-            //await b;
-            //await c;
 
 
-            //foreach (var item in Cysharp.Threading.Tasks.Internal.TaskPool.GetCacheSizeInfo())
-            //{
-            //    Console.WriteLine(item);
-            //}
 
-            Console.ReadLine();
         }
 
         static async UniTask YieldCore()

src/UniTask.NetCoreTests/Linq/CreateTest.cs

@@ -0,0 +1,170 @@
+#pragma warning disable CS1998
+#pragma warning disable CS0162
+
+using Cysharp.Threading.Tasks;
+using Cysharp.Threading.Tasks.Linq;
+using FluentAssertions;
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace NetCoreTests.Linq
+{
+    public class CreateTest
+    {
+        [Fact]
+        public async Task SyncCreation()
+        {
+            var from = 10;
+            var count = 100;
+
+            var xs = await UniTaskAsyncEnumerable.Create<int>(async (writer, token) =>
+            {
+                for (int i = 0; i < count; i++)
+                {
+                    await writer.YieldAsync(from + i);
+                }
+            }).ToArrayAsync();
+
+            var ys = await Range(from, count).AsUniTaskAsyncEnumerable().ToArrayAsync();
+
+            xs.Should().BeEquivalentTo(ys);
+        }
+
+        [Fact]
+        public async Task SyncManually()
+        {
+            var list = new List<int>();
+            var xs = UniTaskAsyncEnumerable.Create<int>(async (writer, token) =>
+            {
+                list.Add(100);
+                await writer.YieldAsync(10);
+                
+                list.Add(200);
+                await writer.YieldAsync(20);
+
+                list.Add(300);
+                await writer.YieldAsync(30);
+            
+                list.Add(400);
+            });
+
+            list.Should().BeEmpty();
+            var e = xs.GetAsyncEnumerator();
+
+            list.Should().BeEmpty();
+
+            await e.MoveNextAsync();
+            list.Should().BeEquivalentTo(100);
+            e.Current.Should().Be(10);
+
+            await e.MoveNextAsync();
+            list.Should().BeEquivalentTo(100, 200);
+            e.Current.Should().Be(20);
+
+            await e.MoveNextAsync();
+            list.Should().BeEquivalentTo(100, 200, 300);
+            e.Current.Should().Be(30);
+
+            (await e.MoveNextAsync()).Should().BeFalse();
+            list.Should().BeEquivalentTo(100, 200, 300, 400);
+        }
+
+        [Fact]
+        public async Task SyncExceptionFirst()
+        {
+            var from = 10;
+            var count = 100;
+
+            var xs = UniTaskAsyncEnumerable.Create<int>(async (writer, token) =>
+            {
+                for (int i = 0; i < count; i++)
+                {
+                    throw new UniTaskTestException();
+                    await writer.YieldAsync(from + i);
+                }
+            });
+
+            await Assert.ThrowsAsync<UniTaskTestException>(async () => await xs.ToArrayAsync());
+        }
+
+        [Fact]
+        public async Task SyncException()
+        {
+            var from = 10;
+            var count = 100;
+
+            var xs = UniTaskAsyncEnumerable.Create<int>(async (writer, token) =>
+            {
+                for (int i = 0; i < count; i++)
+                {
+                    await writer.YieldAsync(from + i);
+
+                    if (i == 15)
+                    {
+                        throw new UniTaskTestException();
+                    }
+                }
+            });
+
+            await Assert.ThrowsAsync<UniTaskTestException>(async () => await xs.ToArrayAsync());
+        }
+
+        [Fact]
+        public async Task ASyncManually()
+        {
+            var list = new List<int>();
+            var xs = UniTaskAsyncEnumerable.Create<int>(async (writer, token) =>
+            {
+                await UniTask.Yield();
+
+                list.Add(100);
+                await writer.YieldAsync(10);
+
+                await UniTask.Yield();
+
+                list.Add(200);
+                await writer.YieldAsync(20);
+
+                await UniTask.Yield();
+                list.Add(300);
+                await UniTask.Yield();
+                await writer.YieldAsync(30);
+
+                await UniTask.Yield();
+
+                list.Add(400);
+            });
+
+            list.Should().BeEmpty();
+            var e = xs.GetAsyncEnumerator();
+
+            list.Should().BeEmpty();
+
+            await e.MoveNextAsync();
+            list.Should().BeEquivalentTo(100);
+            e.Current.Should().Be(10);
+
+            await e.MoveNextAsync();
+            list.Should().BeEquivalentTo(100, 200);
+            e.Current.Should().Be(20);
+
+            await e.MoveNextAsync();
+            list.Should().BeEquivalentTo(100, 200, 300);
+            e.Current.Should().Be(30);
+
+            (await e.MoveNextAsync()).Should().BeFalse();
+            list.Should().BeEquivalentTo(100, 200, 300, 400);
+        }
+
+        async IAsyncEnumerable<int> Range(int from, int count)
+        {
+            for (int i = 0; i < count; i++)
+            {
+                yield return from + i;
+            }
+        }
+    }
+}

src/UniTask/Assets/Plugins/UniTask/Runtime/Linq/Create.cs

@@ -0,0 +1,192 @@
+using Cysharp.Threading.Tasks.Internal;
+using System;
+using System.Threading;
+
+namespace Cysharp.Threading.Tasks.Linq
+{
+    public static partial class UniTaskAsyncEnumerable
+    {
+        public static IUniTaskAsyncEnumerable<T> Create<T>(Func<IAsyncWriter<T>, CancellationToken, UniTask> create)
+        {
+            Error.ThrowArgumentNullException(create, nameof(create));
+            return new Create<T>(create);
+        }
+    }
+
+    public interface IAsyncWriter<T>
+    {
+        UniTask YieldAsync(T value);
+    }
+
+    internal sealed class Create<T> : IUniTaskAsyncEnumerable<T>
+    {
+        readonly Func<IAsyncWriter<T>, CancellationToken, UniTask> create;
+
+        public Create(Func<IAsyncWriter<T>, CancellationToken, UniTask> create)
+        {
+            this.create = create;
+        }
+
+        public IUniTaskAsyncEnumerator<T> GetAsyncEnumerator(CancellationToken cancellationToken = default)
+        {
+            return new _Create(create, cancellationToken);
+        }
+
+        sealed class _Create : MoveNextSource, IUniTaskAsyncEnumerator<T>
+        {
+            readonly Func<IAsyncWriter<T>, CancellationToken, UniTask> create;
+            readonly CancellationToken cancellationToken;
+
+            int state = -1;
+            AsyncWriter writer;
+
+            public _Create(Func<IAsyncWriter<T>, CancellationToken, UniTask> create, CancellationToken cancellationToken)
+            {
+                this.create = create;
+                this.cancellationToken = cancellationToken;
+                TaskTracker.TrackActiveTask(this, 3);
+            }
+
+            public T Current { get; private set; }
+
+            public UniTask DisposeAsync()
+            {
+                TaskTracker.RemoveTracking(this);
+                return default;
+            }
+
+            public UniTask<bool> MoveNextAsync()
+            {
+                if (state == -2) return default;
+
+                completionSource.Reset();
+                MoveNext();
+                return new UniTask<bool>(this, completionSource.Version);
+            }
+
+            void MoveNext()
+            {
+                try
+                {
+                    switch (state)
+                    {
+                        case -1: // init
+                            {
+                                writer = new AsyncWriter(this);
+                                RunWriterTask(create(writer, cancellationToken)).Forget();
+                                if (Volatile.Read(ref state) == -2)
+                                {
+                                    return; // complete synchronously
+                                }
+                                state = 0; // wait YieldAsync, it set TrySetResult(true)
+                                return;
+                            }
+                        case 0:
+                            writer.SignalWriter();
+                            return;
+                        default:
+                            goto DONE;
+                    }
+                }
+                catch (Exception ex)
+                {
+                    state = -2;
+                    completionSource.TrySetException(ex);
+                    return;
+                }
+
+                DONE:
+                state = -2;
+                completionSource.TrySetResult(false);
+                return;
+            }
+
+            async UniTaskVoid RunWriterTask(UniTask task)
+            {
+                try
+                {
+                    await task;
+                    goto DONE;
+                }
+                catch (Exception ex)
+                {
+                    Volatile.Write(ref state, -2);
+                    completionSource.TrySetException(ex);
+                    return;
+                }
+
+                DONE:
+                Volatile.Write(ref state, -2);
+                completionSource.TrySetResult(false);
+            }
+
+            public bool TrySetCanceled(CancellationToken cancellationToken)
+            {
+                state = -2;
+                return completionSource.TrySetCanceled(cancellationToken);
+            }
+
+            public bool TrySetComplete()
+            {
+                state = -2;
+                return completionSource.TrySetResult(false);
+            }
+
+            public bool TrySetException(Exception error)
+            {
+                state = -2;
+                return completionSource.TrySetException(error);
+            }
+
+            public void SetResult(T value)
+            {
+                Current = value;
+                completionSource.TrySetResult(true);
+            }
+        }
+
+        sealed class AsyncWriter : IUniTaskSource, IAsyncWriter<T>
+        {
+            readonly _Create enumerator;
+
+            UniTaskCompletionSourceCore<AsyncUnit> core;
+
+            public AsyncWriter(_Create enumerator)
+            {
+                this.enumerator = enumerator;
+            }
+
+            public void GetResult(short token)
+            {
+                core.GetResult(token);
+            }
+
+            public UniTaskStatus GetStatus(short token)
+            {
+                return core.GetStatus(token);
+            }
+
+            public UniTaskStatus UnsafeGetStatus()
+            {
+                return core.UnsafeGetStatus();
+            }
+
+            public void OnCompleted(Action<object> continuation, object state, short token)
+            {
+                core.OnCompleted(continuation, state, token);
+            }
+
+            public UniTask YieldAsync(T value)
+            {
+                core.Reset();
+                enumerator.SetResult(value);
+                return new UniTask(this, core.Version);
+            }
+
+            public void SignalWriter()
+            {
+                core.TrySetResult(AsyncUnit.Default);
+            }
+        }
+    }
+}

src/UniTask/Assets/Plugins/UniTask/Runtime/Linq/Create.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 0202f723469f93945afa063bfb440d15
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/UniTask/Assets/Plugins/UniTask/Runtime/Linq/Select.cs

@@ -88,6 +88,7 @@ namespace Cysharp.Threading.Tasks.Linq
                 this.selector = selector;
                 this.cancellationToken = cancellationToken;
                 this.moveNextAction = MoveNext;
+                TaskTracker.TrackActiveTask(this, 3);
             }
 
             public TResult Current { get; private set; }
@@ -156,6 +157,7 @@ namespace Cysharp.Threading.Tasks.Linq
 
             public UniTask DisposeAsync()
             {
+                TaskTracker.RemoveTracking(this);
                 return enumerator.DisposeAsync();
             }
         }
@@ -195,6 +197,7 @@ namespace Cysharp.Threading.Tasks.Linq
                 this.selector = selector;
                 this.cancellationToken = cancellationToken;
                 this.moveNextAction = MoveNext;
+                TaskTracker.TrackActiveTask(this, 3);
             }
 
             public TResult Current { get; private set; }
@@ -263,6 +266,7 @@ namespace Cysharp.Threading.Tasks.Linq
 
             public UniTask DisposeAsync()
             {
+                TaskTracker.RemoveTracking(this);
                 return enumerator.DisposeAsync();
             }
         }
@@ -302,6 +306,7 @@ namespace Cysharp.Threading.Tasks.Linq
                 this.selector = selector;
                 this.cancellationToken = cancellationToken;
                 this.moveNextAction = MoveNext;
+                TaskTracker.TrackActiveTask(this, 3);
             }
 
             public TResult Current { get; private set; }
@@ -382,6 +387,7 @@ namespace Cysharp.Threading.Tasks.Linq
 
             public UniTask DisposeAsync()
             {
+                TaskTracker.RemoveTracking(this);
                 return enumerator.DisposeAsync();
             }
         }
@@ -422,6 +428,7 @@ namespace Cysharp.Threading.Tasks.Linq
                 this.selector = selector;
                 this.cancellationToken = cancellationToken;
                 this.moveNextAction = MoveNext;
+                TaskTracker.TrackActiveTask(this, 3);
             }
 
             public TResult Current { get; private set; }
@@ -502,6 +509,7 @@ namespace Cysharp.Threading.Tasks.Linq
 
             public UniTask DisposeAsync()
             {
+                TaskTracker.RemoveTracking(this);
                 return enumerator.DisposeAsync();
             }
         }
@@ -541,6 +549,7 @@ namespace Cysharp.Threading.Tasks.Linq
                 this.selector = selector;
                 this.cancellationToken = cancellationToken;
                 this.moveNextAction = MoveNext;
+                TaskTracker.TrackActiveTask(this, 3);
             }
 
             public TResult Current { get; private set; }
@@ -621,6 +630,7 @@ namespace Cysharp.Threading.Tasks.Linq
 
             public UniTask DisposeAsync()
             {
+                TaskTracker.RemoveTracking(this);
                 return enumerator.DisposeAsync();
             }
         }
@@ -661,6 +671,7 @@ namespace Cysharp.Threading.Tasks.Linq
                 this.selector = selector;
                 this.cancellationToken = cancellationToken;
                 this.moveNextAction = MoveNext;
+                TaskTracker.TrackActiveTask(this, 3);
             }
 
             public TResult Current { get; private set; }
@@ -741,6 +752,7 @@ namespace Cysharp.Threading.Tasks.Linq
 
             public UniTask DisposeAsync()
             {
+                TaskTracker.RemoveTracking(this);
                 return enumerator.DisposeAsync();
             }
         }

src/UniTask/Assets/Plugins/UniTask/Runtime/Linq/Where.cs

@@ -88,6 +88,7 @@ namespace Cysharp.Threading.Tasks.Linq
                 this.predicate = predicate;
                 this.cancellationToken = cancellationToken;
                 this.moveNextAction = MoveNext;
+                TaskTracker.TrackActiveTask(this, 3);
             }
 
             public TSource Current { get; private set; }
@@ -165,6 +166,7 @@ namespace Cysharp.Threading.Tasks.Linq
 
             public UniTask DisposeAsync()
             {
+                TaskTracker.RemoveTracking(this);
                 return enumerator.DisposeAsync();
             }
         }
@@ -204,6 +206,7 @@ namespace Cysharp.Threading.Tasks.Linq
                 this.predicate = predicate;
                 this.cancellationToken = cancellationToken;
                 this.moveNextAction = MoveNext;
+                TaskTracker.TrackActiveTask(this, 3);
             }
 
             public TSource Current { get; private set; }
@@ -281,6 +284,7 @@ namespace Cysharp.Threading.Tasks.Linq
 
             public UniTask DisposeAsync()
             {
+                TaskTracker.RemoveTracking(this);
                 return enumerator.DisposeAsync();
             }
         }
@@ -320,6 +324,7 @@ namespace Cysharp.Threading.Tasks.Linq
                 this.predicate = predicate;
                 this.cancellationToken = cancellationToken;
                 this.moveNextAction = MoveNext;
+                TaskTracker.TrackActiveTask(this, 3);
             }
 
             public TSource Current { get; private set; }
@@ -410,6 +415,7 @@ namespace Cysharp.Threading.Tasks.Linq
 
             public UniTask DisposeAsync()
             {
+                TaskTracker.RemoveTracking(this);
                 return enumerator.DisposeAsync();
             }
         }
@@ -450,6 +456,7 @@ namespace Cysharp.Threading.Tasks.Linq
                 this.predicate = predicate;
                 this.cancellationToken = cancellationToken;
                 this.moveNextAction = MoveNext;
+                TaskTracker.TrackActiveTask(this, 3);
             }
 
             public TSource Current { get; private set; }
@@ -540,6 +547,7 @@ namespace Cysharp.Threading.Tasks.Linq
 
             public UniTask DisposeAsync()
             {
+                TaskTracker.RemoveTracking(this);
                 return enumerator.DisposeAsync();
             }
         }
@@ -579,6 +587,7 @@ namespace Cysharp.Threading.Tasks.Linq
                 this.predicate = predicate;
                 this.cancellationToken = cancellationToken;
                 this.moveNextAction = MoveNext;
+                TaskTracker.TrackActiveTask(this, 3);
             }
 
             public TSource Current { get; private set; }
@@ -669,6 +678,7 @@ namespace Cysharp.Threading.Tasks.Linq
 
             public UniTask DisposeAsync()
             {
+                TaskTracker.RemoveTracking(this);
                 return enumerator.DisposeAsync();
             }
         }
@@ -709,6 +719,7 @@ namespace Cysharp.Threading.Tasks.Linq
                 this.predicate = predicate;
                 this.cancellationToken = cancellationToken;
                 this.moveNextAction = MoveNext;
+                TaskTracker.TrackActiveTask(this, 3);
             }
 
             public TSource Current { get; private set; }
@@ -799,6 +810,7 @@ namespace Cysharp.Threading.Tasks.Linq
 
             public UniTask DisposeAsync()
             {
+                TaskTracker.RemoveTracking(this);
                 return enumerator.DisposeAsync();
             }
         }

src/UniTask/Assets/Plugins/UniTask/Runtime/UniTask.Factory.cs

@@ -175,6 +175,22 @@ namespace Cysharp.Threading.Tasks
             return new UniTask<T>(new DeferPromise<T>(factory), 0);
         }
 
+        /// <summary>
+        /// Never complete.
+        /// </summary>
+        public static UniTask Never(CancellationToken cancellationToken)
+        {
+            return new UniTask<AsyncUnit>(new NeverPromise<AsyncUnit>(cancellationToken), 0);
+        }
+
+        /// <summary>
+        /// Never complete.
+        /// </summary>
+        public static UniTask<T> Never<T>(CancellationToken cancellationToken)
+        {
+            return new UniTask<T>(new NeverPromise<T>(cancellationToken), 0);
+        }
+
         sealed class ExceptionResultSource : IUniTaskSource
         {
             readonly ExceptionDispatchInfo exception;
@@ -384,6 +400,54 @@ namespace Cysharp.Threading.Tasks
                 return task.Status;
             }
         }
+
+        sealed class NeverPromise<T> : IUniTaskSource<T>
+        {
+            static readonly Action<object> cancellationCallback = CancellationCallback;
+
+            CancellationToken cancellationToken;
+            UniTaskCompletionSourceCore<T> core;
+
+            public NeverPromise(CancellationToken cancellationToken)
+            {
+                this.cancellationToken = cancellationToken;
+                if (this.cancellationToken.CanBeCanceled)
+                {
+                    this.cancellationToken.RegisterWithoutCaptureExecutionContext(cancellationCallback, this);
+                }
+            }
+
+            static void CancellationCallback(object state)
+            {
+                var self = (NeverPromise<T>)state;
+                self.core.TrySetCanceled(self.cancellationToken);
+            }
+
+            public T GetResult(short token)
+            {
+                return core.GetResult(token);
+            }
+
+            public UniTaskStatus GetStatus(short token)
+            {
+                return core.GetStatus(token);
+            }
+
+            public UniTaskStatus UnsafeGetStatus()
+            {
+                return core.UnsafeGetStatus();
+            }
+
+            public void OnCompleted(Action<object> continuation, object state, short token)
+            {
+                core.OnCompleted(continuation, state, token);
+            }
+
+            void IUniTaskSource.GetResult(short token)
+            {
+                core.GetResult(token);
+            }
+        }
     }
 
     internal static class CompletedTasks

src/UniTask/Assets/Plugins/UniTask/Runtime/UniTaskCompletionSource.cs

@@ -229,7 +229,7 @@ namespace Cysharp.Threading.Tasks
             ValidateToken(token);
             if (completedCount == 0)
             {
-                throw new InvalidOperationException("not yet completed.");
+                throw new InvalidOperationException("Not yet completed, UniTask only allow to use await.");
             }
 
             if (error != null)
@@ -288,7 +288,7 @@ namespace Cysharp.Threading.Tasks
                 // It will cause call OnCompleted multiple time, invalid.
                 if (!ReferenceEquals(oldContinuation, UniTaskCompletionSourceCoreShared.s_sentinel))
                 {
-                    throw new InvalidOperationException();
+                    throw new InvalidOperationException("Already continuation registered, can not await twice or get Status after await.");
                 }
 
                 continuation(state);

src/UniTask/Assets/Plugins/UniTask/package.json

@@ -1,7 +1,7 @@
 {
     "name": "com.cysharp.unitask",
     "displayName": "UniTask",
-    "version": "2.0.23",
+    "version": "2.0.24",
     "unity": "2018.4",
     "description": "Provides an efficient async/await integration to Unity.",
     "keywords": [ "async/await", "async", "Task", "UniTask" ],

src/UniTask/Assets/Scenes/ExceptionExamples.cs

@@ -1,46 +1,52 @@
-using System;
-using System.Threading.Tasks;
-using Cysharp.Threading.Tasks;
-using Cysharp.Threading.Tasks.Linq;
+using Cysharp.Threading.Tasks;
+using System;
+using System.Collections.Generic;
 using UnityEngine;
-using UnityEngine.Networking;
-using UnityEngine.UI;
 
+/*UNniTastWhenAnyTester*/
+
+[ExecuteInEditMode]
 public class ExceptionExamples : MonoBehaviour
 {
-    public Button ButtonTest;
+    public bool apply = false;
 
-    void Start()
+    private async UniTaskVoid Update()
     {
-        ButtonTest.OnClickAsAsyncEnumerable()
-            .Subscribe(async _ =>
+        if (apply)
+        {
+            apply = false;
+            await LaunchTasksAndDetectWhenAnyDone(5);
+        }
+    }
+
+    private async UniTask LaunchTasksAndDetectWhenAnyDone(int nbTasks)
+    {
+        List<UniTask<int>> sleeptasks = new List<UniTask<int>>();
+        for (int i = 0; i < nbTasks; i++)
+        {
+            sleeptasks.Add(SleepAndReturnTrue(i).ToAsyncLazy().Task);
+        }
+        while (sleeptasks.Count > 0)
+        {
+            Debug.Log(DateTime.Now.ToString() + " waiting for " + sleeptasks.Count + " tasks...");
+            try
             {
-                try
-                {
-                    await new Foo().MethodFooAsync();
-                }
-                catch (Exception e)
-                {
-                    Debug.Log(e.StackTrace);
-                }
-            }, this.GetCancellationTokenOnDestroy());
-    }
-}
-
-class Foo
-{
-    public async UniTask MethodFooAsync()
-    {
-        await MethodBarAsync();
+                (int index, int taskID) = await UniTask.WhenAny(sleeptasks);
+                Debug.Log(DateTime.Now.ToString() + " Sleep task " + taskID + " done");
+                sleeptasks.RemoveAt(index);
+            }
+            catch
+            {
+                throw;
+                //Debug.Log("Error: " + e.Message);
+                //return;
+            }
+        }
     }
 
-    private async UniTask MethodBarAsync()
+    private async UniTask<int> SleepAndReturnTrue(int taskIndex)
     {
-        Throw();
-    }
-
-    private void Throw()
-    {
-        throw new Exception();
+        await UniTask.Delay(100);
+        return taskIndex;
     }
 }

src/UniTask/Assets/Scenes/SandboxMain.cs

@@ -459,18 +459,41 @@ public class SandboxMain : MonoBehaviour
         PrepareCamera();
     }
 
+    public IUniTaskAsyncEnumerable<int> MyEveryUpdate()
+    {
+        return UniTaskAsyncEnumerable.Create<int>(async (writer, token) =>
+        {
+            var frameCount = 0;
+            await UniTask.Yield();
+            while (!token.IsCancellationRequested)
+            {
+                await writer.YieldAsync(frameCount++); // instead of `yield return`
+                await UniTask.Yield();
+            }
+        });
+    }
+
 
     async UniTaskVoid Start()
     {
+        var cts = new CancellationTokenSource();
         okButton.onClick.AddListener(() =>
         {
-            ShootAsync().Forget();
+            cts.Cancel();
         });
 
-        // Nanika();
+        //// Nanika();
+
+
+        //await UniTask.Yield();
+
+
+        await MyEveryUpdate().Select(x => x).Where(x => x % 2 == 0).ForEachAsync(x =>
+                {
+                    UnityEngine.Debug.Log(x + ":" + Time.frameCount);
+                }, cts.Token);
 
 
-        await UniTask.Yield();
         // this.GetCancellationTokenOnDestroy()
 
         //PlayerLoopInfo.Inject();
@@ -992,17 +1015,17 @@ public class SandboxMain : MonoBehaviour
 
     void PrepareCamera()
     {
-        Debug.Log("Support AsyncGPUReadback:" + SystemInfo.supportsAsyncGPUReadback);
+        //Debug.Log("Support AsyncGPUReadback:" + SystemInfo.supportsAsyncGPUReadback);
 
-        var width = 480;
-        var height = 240;
-        var depth = 24;
+        //var width = 480;
+        //var height = 240;
+        //var depth = 24;
 
-        mycamera.targetTexture = new RenderTexture(width, height, depth, RenderTextureFormat.ARGB32, RenderTextureReadWrite.Default)
-        {
-            antiAliasing = 8
-        };
-        mycamera.enabled = true;
+        //mycamera.targetTexture = new RenderTexture(width, height, depth, RenderTextureFormat.ARGB32, RenderTextureReadWrite.Default)
+        //{
+        //    antiAliasing = 8
+        //};
+        //mycamera.enabled = true;
 
         //myRenderTexture = new RenderTexture(width, height, depth, RenderTextureFormat.ARGB32, RenderTextureReadWrite.Default)
         //{