Merge pull request #557 from Cysharp/hadashiA/fix-cancel-immediate

Fix unintended returning to pool with cancelImmediately

src/UniTask/Assets/Plugins/UniTask/Runtime/External/Addressables/AddressablesAsyncExtensions.cs

@@ -110,6 +110,7 @@ namespace Cysharp.Threading.Tasks
             CancellationTokenRegistration cancellationTokenRegistration;
             IProgress<float> progress;
             bool autoReleaseWhenCanceled;
+            bool cancelImmediately;
             bool completed;
 
             UniTaskCompletionSourceCore<AsyncUnit> core;
@@ -134,8 +135,9 @@ namespace Cysharp.Threading.Tasks
                 result.handle = handle;
                 result.progress = progress;
                 result.cancellationToken = cancellationToken;
-                result.completed = false;
+                result.cancelImmediately = cancelImmediately;
                 result.autoReleaseWhenCanceled = autoReleaseWhenCanceled;
+                result.completed = false;
                 
                 if (cancelImmediately && cancellationToken.CanBeCanceled)
                 {
@@ -169,33 +171,41 @@ namespace Cysharp.Threading.Tasks
 
                 if (completed)
                 {
-                    TryReturn();
+                    return;
+                }
+                
+                completed = true;
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    if (autoReleaseWhenCanceled && handle.IsValid())
+                    {
+                        Addressables.Release(handle);
+                    }
+                    core.TrySetCanceled(cancellationToken);
+                }
+                else if (handle.Status == AsyncOperationStatus.Failed)
+                {
+                    core.TrySetException(handle.OperationException);
                 }
                 else
                 {
-                    completed = true;
+                    core.TrySetResult(AsyncUnit.Default);
-                    if (cancellationToken.IsCancellationRequested)
-                    {
-                        if (autoReleaseWhenCanceled && handle.IsValid())
-                        {
-                            Addressables.Release(handle);
-                        }
-                        core.TrySetCanceled(cancellationToken);
-                    }
-                    else if (handle.Status == AsyncOperationStatus.Failed)
-                    {
-                        core.TrySetException(handle.OperationException);
-                    }
-                    else
-                    {
-                        core.TrySetResult(AsyncUnit.Default);
-                    }
                 }
             }
 
             public void GetResult(short token)
             {
-                core.GetResult(token);
+                try
+                {
+                    core.GetResult(token);
+                }
+                finally
+                {
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
+                }
             }
 
             public UniTaskStatus GetStatus(short token)
@@ -217,7 +227,6 @@ namespace Cysharp.Threading.Tasks
             {
                 if (completed)
                 {
-                    TryReturn();
                     return false;
                 }
 
@@ -304,6 +313,7 @@ namespace Cysharp.Threading.Tasks
             CancellationTokenRegistration cancellationTokenRegistration;
             IProgress<float> progress;
             bool autoReleaseWhenCanceled;
+            bool cancelImmediately;
             bool completed;
 
             UniTaskCompletionSourceCore<T> core;
@@ -330,6 +340,7 @@ namespace Cysharp.Threading.Tasks
                 result.completed = false;
                 result.progress = progress;
                 result.autoReleaseWhenCanceled = autoReleaseWhenCanceled;
+                result.cancelImmediately = cancelImmediately;
                 
                 if (cancelImmediately && cancellationToken.CanBeCanceled)
                 {
@@ -363,33 +374,38 @@ namespace Cysharp.Threading.Tasks
 
                 if (completed)
                 {
-                    TryReturn();
+                    return;
+                }
+                completed = true;
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    if (autoReleaseWhenCanceled && handle.IsValid())
+                    {
+                        Addressables.Release(handle);
+                    }
+                    core.TrySetCanceled(cancellationToken);
+                }
+                else if (argHandle.Status == AsyncOperationStatus.Failed)
+                {
+                    core.TrySetException(argHandle.OperationException);
                 }
                 else
                 {
-                    completed = true;
+                    core.TrySetResult(argHandle.Result);
-                    if (cancellationToken.IsCancellationRequested)
-                    {
-                        if (autoReleaseWhenCanceled && handle.IsValid())
-                        {
-                            Addressables.Release(handle);
-                        }
-                        core.TrySetCanceled(cancellationToken);
-                    }
-                    else if (argHandle.Status == AsyncOperationStatus.Failed)
-                    {
-                        core.TrySetException(argHandle.OperationException);
-                    }
-                    else
-                    {
-                        core.TrySetResult(argHandle.Result);
-                    }
                 }
             }
 
             public T GetResult(short token)
             {
-                return core.GetResult(token);
+                try
+                {
+                    return core.GetResult(token);
+                }
+                finally
+                {
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                        TryReturn();
+                }
             }
 
             void IUniTaskSource.GetResult(short token)
@@ -416,7 +432,6 @@ namespace Cysharp.Threading.Tasks
             {
                 if (completed)
                 {
-                    TryReturn();
                     return false;
                 }
 

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

@@ -208,6 +208,7 @@ namespace Cysharp.Threading.Tasks
 
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
             UniTaskCompletionSourceCore<object> core;
 
             YieldPromise()
@@ -227,6 +228,7 @@ namespace Cysharp.Threading.Tasks
                 }
 
                 result.cancellationToken = cancellationToken;
+                result.cancelImmediately = cancelImmediately;
                 
                 if (cancelImmediately && cancellationToken.CanBeCanceled)
                 {
@@ -253,7 +255,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -290,6 +295,7 @@ namespace Cysharp.Threading.Tasks
                 core.Reset();
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
         }
@@ -309,6 +315,7 @@ namespace Cysharp.Threading.Tasks
             UniTaskCompletionSourceCore<AsyncUnit> core;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
 
             NextFramePromise()
             {
@@ -328,6 +335,7 @@ namespace Cysharp.Threading.Tasks
 
                 result.frameCount = PlayerLoopHelper.IsMainThread ? Time.frameCount : -1;
                 result.cancellationToken = cancellationToken;
+                result.cancelImmediately = cancelImmediately;
 
                 if (cancelImmediately && cancellationToken.CanBeCanceled)
                 {
@@ -354,7 +362,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -414,6 +425,7 @@ namespace Cysharp.Threading.Tasks
             UniTaskCompletionSourceCore<object> core;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
 
             WaitForEndOfFramePromise()
             {
@@ -432,6 +444,7 @@ namespace Cysharp.Threading.Tasks
                 }
 
                 result.cancellationToken = cancellationToken;
+                result.cancelImmediately = cancelImmediately;
 
                 if (cancelImmediately && cancellationToken.CanBeCanceled)
                 {
@@ -458,7 +471,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -533,6 +549,7 @@ namespace Cysharp.Threading.Tasks
             int delayFrameCount;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
 
             int currentFrameCount;
             UniTaskCompletionSourceCore<AsyncUnit> core;
@@ -556,6 +573,7 @@ namespace Cysharp.Threading.Tasks
                 result.delayFrameCount = delayFrameCount;
                 result.cancellationToken = cancellationToken;
                 result.initialFrame = PlayerLoopHelper.IsMainThread ? Time.frameCount : -1;
+                result.cancelImmediately = cancelImmediately;
 
                 if (cancelImmediately && cancellationToken.CanBeCanceled)
                 {
@@ -582,7 +600,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -653,6 +674,7 @@ namespace Cysharp.Threading.Tasks
                 delayFrameCount = default;
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
         }
@@ -673,6 +695,7 @@ namespace Cysharp.Threading.Tasks
             float elapsed;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
 
             UniTaskCompletionSourceCore<object> core;
 
@@ -696,6 +719,7 @@ namespace Cysharp.Threading.Tasks
                 result.delayTimeSpan = (float)delayTimeSpan.TotalSeconds;
                 result.cancellationToken = cancellationToken;
                 result.initialFrame = PlayerLoopHelper.IsMainThread ? Time.frameCount : -1;
+                result.cancelImmediately = cancelImmediately;
 
                 if (cancelImmediately && cancellationToken.CanBeCanceled)
                 {
@@ -722,7 +746,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -775,6 +802,7 @@ namespace Cysharp.Threading.Tasks
                 elapsed = default;
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
         }
@@ -795,6 +823,7 @@ namespace Cysharp.Threading.Tasks
             int initialFrame;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
 
             UniTaskCompletionSourceCore<object> core;
 
@@ -818,6 +847,7 @@ namespace Cysharp.Threading.Tasks
                 result.delayFrameTimeSpan = (float)delayFrameTimeSpan.TotalSeconds;
                 result.initialFrame = PlayerLoopHelper.IsMainThread ? Time.frameCount : -1;
                 result.cancellationToken = cancellationToken;
+                result.cancelImmediately = cancelImmediately;
 
                 if (cancelImmediately && cancellationToken.CanBeCanceled)
                 {
@@ -844,7 +874,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -897,6 +930,7 @@ namespace Cysharp.Threading.Tasks
                 elapsed = default;
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
         }
@@ -916,6 +950,7 @@ namespace Cysharp.Threading.Tasks
             ValueStopwatch stopwatch;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
 
             UniTaskCompletionSourceCore<AsyncUnit> core;
 
@@ -938,6 +973,7 @@ namespace Cysharp.Threading.Tasks
                 result.stopwatch = ValueStopwatch.StartNew();
                 result.delayTimeSpanTicks = delayTimeSpan.Ticks;
                 result.cancellationToken = cancellationToken;
+                result.cancelImmediately = cancelImmediately;
 
                 if (cancelImmediately && cancellationToken.CanBeCanceled)
                 {
@@ -964,7 +1000,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -1013,6 +1052,7 @@ namespace Cysharp.Threading.Tasks
                 stopwatch = default;
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
         }

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

@@ -49,6 +49,7 @@ namespace Cysharp.Threading.Tasks
             Func<bool> predicate;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
 
             UniTaskCompletionSourceCore<object> core;
 
@@ -70,6 +71,7 @@ namespace Cysharp.Threading.Tasks
 
                 result.predicate = predicate;
                 result.cancellationToken = cancellationToken;
+                result.cancelImmediately = cancelImmediately;
 
                 if (cancelImmediately && cancellationToken.CanBeCanceled)
                 {
@@ -96,7 +98,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -147,6 +152,7 @@ namespace Cysharp.Threading.Tasks
                 predicate = default;
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
         }
@@ -165,6 +171,7 @@ namespace Cysharp.Threading.Tasks
             Func<bool> predicate;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
 
             UniTaskCompletionSourceCore<object> core;
 
@@ -212,7 +219,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -263,6 +273,7 @@ namespace Cysharp.Threading.Tasks
                 predicate = default;
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
         }
@@ -280,6 +291,7 @@ namespace Cysharp.Threading.Tasks
 
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
 
             UniTaskCompletionSourceCore<object> core;
 
@@ -287,7 +299,7 @@ namespace Cysharp.Threading.Tasks
             {
             }
 
-            public static IUniTaskSource Create(CancellationToken cancellationToken, PlayerLoopTiming timing, bool completeImmediately, out short token)
+            public static IUniTaskSource Create(CancellationToken cancellationToken, PlayerLoopTiming timing, bool cancelImmediately, out short token)
             {
                 if (cancellationToken.IsCancellationRequested)
                 {
@@ -300,8 +312,9 @@ namespace Cysharp.Threading.Tasks
                 }
 
                 result.cancellationToken = cancellationToken;
+                result.cancelImmediately = cancelImmediately;
 
-                if (completeImmediately && cancellationToken.CanBeCanceled)
+                if (cancelImmediately && cancellationToken.CanBeCanceled)
                 {
                     result.cancellationTokenRegistration = cancellationToken.RegisterWithoutCaptureExecutionContext(state =>
                     {
@@ -326,7 +339,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -362,6 +378,7 @@ namespace Cysharp.Threading.Tasks
                 core.Reset();
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
         }
@@ -385,6 +402,7 @@ namespace Cysharp.Threading.Tasks
             IEqualityComparer<U> equalityComparer;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
 
             UniTaskCompletionSourceCore<U> core;
 
@@ -410,6 +428,7 @@ namespace Cysharp.Threading.Tasks
                 result.currentValue = monitorFunction(target);
                 result.equalityComparer = equalityComparer ?? UnityEqualityComparer.GetDefault<U>();
                 result.cancellationToken = cancellationToken;
+                result.cancelImmediately = cancelImmediately;
                 
                 if (cancelImmediately && cancellationToken.CanBeCanceled)
                 {
@@ -436,7 +455,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -497,6 +519,7 @@ namespace Cysharp.Threading.Tasks
                 equalityComparer = default;
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
         }
@@ -519,6 +542,7 @@ namespace Cysharp.Threading.Tasks
             IEqualityComparer<U> equalityComparer;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
 
             UniTaskCompletionSourceCore<U> core;
 
@@ -543,6 +567,7 @@ namespace Cysharp.Threading.Tasks
                 result.currentValue = monitorFunction(target);
                 result.equalityComparer = equalityComparer ?? UnityEqualityComparer.GetDefault<U>();
                 result.cancellationToken = cancellationToken;
+                result.cancelImmediately = cancelImmediately;
                 
                 if (cancelImmediately && cancellationToken.CanBeCanceled)
                 {
@@ -569,7 +594,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -630,6 +658,7 @@ namespace Cysharp.Threading.Tasks
                 equalityComparer = default;
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
         }

src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.AssetBundleRequestAllAssets.cs

@@ -101,6 +101,7 @@ namespace Cysharp.Threading.Tasks
             IProgress<float> progress;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
             bool completed;
 
             UniTaskCompletionSourceCore<UnityEngine.Object[]> core;
@@ -127,6 +128,7 @@ namespace Cysharp.Threading.Tasks
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
                 result.cancellationToken = cancellationToken;
+                result.cancelImmediately = cancelImmediately;
                 result.completed = false;
 
                 asyncOperation.completed += result.continuationAction;
@@ -156,7 +158,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -216,6 +221,7 @@ namespace Cysharp.Threading.Tasks
                 progress = default;
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
             
@@ -223,19 +229,17 @@ namespace Cysharp.Threading.Tasks
             {
                 if (completed)
                 {
-                    TryReturn();
+                    return;
+                }
+                
+                completed = true;
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    core.TrySetCanceled(cancellationToken);
                 }
                 else
                 {
-                    completed = true;
+                    core.TrySetResult(asyncOperation.allAssets);
-                    if (cancellationToken.IsCancellationRequested)
-                    {
-                        core.TrySetCanceled(cancellationToken);
-                    }
-                    else
-                    {
-                        core.TrySetResult(asyncOperation.allAssets);
-                    }
                 }
             }
         }

src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.AsyncGPUReadback.cs

@@ -45,7 +45,7 @@ namespace Cysharp.Threading.Tasks
             AsyncGPUReadbackRequest asyncOperation;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
-
+            bool cancelImmediately;
             UniTaskCompletionSourceCore<AsyncGPUReadbackRequest> core;
 
             AsyncGPUReadbackRequestAwaiterConfiguredSource()
@@ -66,6 +66,7 @@ namespace Cysharp.Threading.Tasks
 
                 result.asyncOperation = asyncOperation;
                 result.cancellationToken = cancellationToken;
+                result.cancelImmediately = cancelImmediately;
                 
                 if (cancelImmediately && cancellationToken.CanBeCanceled)
                 {
@@ -92,7 +93,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -146,6 +150,7 @@ namespace Cysharp.Threading.Tasks
                 asyncOperation = default;
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
         }

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

@@ -97,6 +97,7 @@ namespace Cysharp.Threading.Tasks
             IProgress<float> progress;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
             bool completed;
 
             UniTaskCompletionSourceCore<AsyncUnit> core;
@@ -123,6 +124,7 @@ namespace Cysharp.Threading.Tasks
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
                 result.cancellationToken = cancellationToken;
+                result.cancelImmediately = cancelImmediately;
                 result.completed = false;
                 
                 asyncOperation.completed += result.continuationAction;
@@ -152,7 +154,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -209,6 +214,7 @@ namespace Cysharp.Threading.Tasks
                 progress = default;
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
 
@@ -216,19 +222,16 @@ namespace Cysharp.Threading.Tasks
             {
                 if (completed)
                 {
-                    TryReturn();
+                    return;
+                }
+                completed = true;
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    core.TrySetCanceled(cancellationToken);
                 }
                 else
                 {
-                    completed = true;
+                    core.TrySetResult(AsyncUnit.Default);
-                    if (cancellationToken.IsCancellationRequested)
-                    {
-                        core.TrySetCanceled(cancellationToken);
-                    }
-                    else
-                    {
-                        core.TrySetResult(AsyncUnit.Default);
-                    }
                 }
             }
         }
@@ -320,6 +323,7 @@ namespace Cysharp.Threading.Tasks
             IProgress<float> progress;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
             bool completed;
 
             UniTaskCompletionSourceCore<UnityEngine.Object> core;
@@ -346,6 +350,7 @@ namespace Cysharp.Threading.Tasks
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
                 result.cancellationToken = cancellationToken;
+                result.cancelImmediately = cancelImmediately;
                 result.completed = false;
                 
                 asyncOperation.completed += result.continuationAction;
@@ -375,7 +380,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -436,6 +444,7 @@ namespace Cysharp.Threading.Tasks
                 progress = default;
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
 
@@ -443,19 +452,16 @@ namespace Cysharp.Threading.Tasks
             {
                 if (completed)
                 {
-                    TryReturn();
+                    return;
+                }
+                completed = true;
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    core.TrySetCanceled(cancellationToken);
                 }
                 else
                 {
-                    completed = true;
+                    core.TrySetResult(asyncOperation.asset);
-                    if (cancellationToken.IsCancellationRequested)
-                    {
-                        core.TrySetCanceled(cancellationToken);
-                    }
-                    else
-                    {
-                        core.TrySetResult(asyncOperation.asset);
-                    }
                 }
             }
         }
@@ -548,6 +554,7 @@ namespace Cysharp.Threading.Tasks
             IProgress<float> progress;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
             bool completed;
 
             UniTaskCompletionSourceCore<UnityEngine.Object> core;
@@ -574,6 +581,7 @@ namespace Cysharp.Threading.Tasks
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
                 result.cancellationToken = cancellationToken;
+                result.cancelImmediately = cancelImmediately;
                 result.completed = false;
                 
                 asyncOperation.completed += result.continuationAction;
@@ -603,7 +611,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -664,6 +675,7 @@ namespace Cysharp.Threading.Tasks
                 progress = default;
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
 
@@ -671,19 +683,16 @@ namespace Cysharp.Threading.Tasks
             {
                 if (completed)
                 {
-                    TryReturn();
+                    return;
+                }
+                completed = true;
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    core.TrySetCanceled(cancellationToken);
                 }
                 else
                 {
-                    completed = true;
+                    core.TrySetResult(asyncOperation.asset);
-                    if (cancellationToken.IsCancellationRequested)
-                    {
-                        core.TrySetCanceled(cancellationToken);
-                    }
-                    else
-                    {
-                        core.TrySetResult(asyncOperation.asset);
-                    }
                 }
             }
         }
@@ -777,6 +786,7 @@ namespace Cysharp.Threading.Tasks
             IProgress<float> progress;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
             bool completed;
 
             UniTaskCompletionSourceCore<AssetBundle> core;
@@ -803,6 +813,7 @@ namespace Cysharp.Threading.Tasks
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
                 result.cancellationToken = cancellationToken;
+                result.cancelImmediately = cancelImmediately;
                 result.completed = false;
                 
                 asyncOperation.completed += result.continuationAction;
@@ -832,7 +843,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -893,6 +907,7 @@ namespace Cysharp.Threading.Tasks
                 progress = default;
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
 
@@ -900,19 +915,16 @@ namespace Cysharp.Threading.Tasks
             {
                 if (completed)
                 {
-                    TryReturn();
+                    return;
+                }
+                completed = true;
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    core.TrySetCanceled(cancellationToken);
                 }
                 else
                 {
-                    completed = true;
+                    core.TrySetResult(asyncOperation.assetBundle);
-                    if (cancellationToken.IsCancellationRequested)
-                    {
-                        core.TrySetCanceled(cancellationToken);
-                    }
-                    else
-                    {
-                        core.TrySetResult(asyncOperation.assetBundle);
-                    }
                 }
             }
         }
@@ -1021,6 +1033,7 @@ namespace Cysharp.Threading.Tasks
             IProgress<float> progress;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
             bool completed;
 
             UniTaskCompletionSourceCore<UnityWebRequest> core;
@@ -1047,6 +1060,7 @@ namespace Cysharp.Threading.Tasks
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
                 result.cancellationToken = cancellationToken;
+                result.cancelImmediately = cancelImmediately;
                 result.completed = false;
                 
                 asyncOperation.completed += result.continuationAction;
@@ -1077,7 +1091,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -1146,6 +1163,7 @@ namespace Cysharp.Threading.Tasks
                 progress = default;
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
 
@@ -1153,23 +1171,20 @@ namespace Cysharp.Threading.Tasks
             {
                 if (completed)
                 {
-                    TryReturn();
+                    return;
+                }
+                completed = true;
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    core.TrySetCanceled(cancellationToken);
+                }
+                else if (asyncOperation.webRequest.IsError())
+                {
+                    core.TrySetException(new UnityWebRequestException(asyncOperation.webRequest));
                 }
                 else
                 {
-                    completed = true;
+                    core.TrySetResult(asyncOperation.webRequest);
-                    if (cancellationToken.IsCancellationRequested)
-                    {
-                        core.TrySetCanceled(cancellationToken);
-                    }
-                    else if (asyncOperation.webRequest.IsError())
-                    {
-                        core.TrySetException(new UnityWebRequestException(asyncOperation.webRequest));
-                    }
-                    else
-                    {
-                        core.TrySetResult(asyncOperation.webRequest);
-                    }
                 }
             }
         }

src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.tt

@@ -165,6 +165,7 @@ namespace Cysharp.Threading.Tasks
             IProgress<float> progress;
             CancellationToken cancellationToken;
             CancellationTokenRegistration cancellationTokenRegistration;
+            bool cancelImmediately;
             bool completed;
 
             UniTaskCompletionSourceCore<<#= IsVoid(t) ? "AsyncUnit" : t.returnType #>> core;
@@ -191,6 +192,7 @@ namespace Cysharp.Threading.Tasks
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
                 result.cancellationToken = cancellationToken;
+                result.cancelImmediately = cancelImmediately;
                 result.completed = false;
                 
                 asyncOperation.completed += result.continuationAction;
@@ -227,7 +229,10 @@ namespace Cysharp.Threading.Tasks
                 }
                 finally
                 {
-                    TryReturn();
+                    if (!(cancelImmediately && cancellationToken.IsCancellationRequested))
+                    {
+                        TryReturn();
+                    }
                 }
             }
 
@@ -304,6 +309,7 @@ namespace Cysharp.Threading.Tasks
                 progress = default;
                 cancellationToken = default;
                 cancellationTokenRegistration.Dispose();
+                cancelImmediately = default;
                 return pool.TryPush(this);
             }
 
@@ -311,31 +317,28 @@ namespace Cysharp.Threading.Tasks
             {
                 if (completed)
                 {
-                    TryReturn();
+                    return;
+                }
+                completed = true;
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    core.TrySetCanceled(cancellationToken);
+                }
+<# if(IsUnityWebRequest(t)) { #>
+                else if (asyncOperation.webRequest.IsError())
+                {
+                    core.TrySetException(new UnityWebRequestException(asyncOperation.webRequest));
                 }
                 else
                 {
-                    completed = true;
+                    core.TrySetResult(asyncOperation.webRequest);
-                    if (cancellationToken.IsCancellationRequested)
-                    {
-                        core.TrySetCanceled(cancellationToken);
-                    }
-<# if(IsUnityWebRequest(t)) { #>
-                    else if (asyncOperation.webRequest.IsError())
-                    {
-                        core.TrySetException(new UnityWebRequestException(asyncOperation.webRequest));
-                    }
-                    else
-                    {
-                        core.TrySetResult(asyncOperation.webRequest);
-                    }
-<# } else { #>
-                    else
-                    {
-                        core.TrySetResult(<#= IsVoid(t) ? "AsyncUnit.Default" : $"asyncOperation.{t.returnField}" #>);
-                    }
-<# } #>
                 }
+<# } else { #>
+                else
+                {
+                    core.TrySetResult(<#= IsVoid(t) ? "AsyncUnit.Default" : $"asyncOperation.{t.returnField}" #>);
+                }
+<# } #>
             }
         }