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Merged
merged 1 commit into from
Jun 5, 2020
Merged

Make Task.WhenAny(task, task) public #37448

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6 changes: 2 additions & 4 deletions src/libraries/System.Private.CoreLib/src/System/Threading/Tasks/Task.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -5952,7 +5952,6 @@ public static Task<Task> WhenAny(params Task[] tasks)
return TaskFactory.CommonCWAnyLogic(tasksCopy);
}

// TODO https://github.com/dotnet/runtime/issues/23021: Make this public.
/// <summary>Creates a task that will complete when either of the supplied tasks have completed.</summary>
/// <param name="task1">The first task to wait on for completion.</param>
/// <param name="task2">The second task to wait on for completion.</param>
Expand All @@ -5964,7 +5963,7 @@ public static Task<Task> WhenAny(params Task[] tasks)
/// <exception cref="System.ArgumentNullException">
/// The <paramref name="task1"/> or <paramref name="task2"/> argument was null.
/// </exception>
internal static Task<Task> WhenAny(Task task1, Task task2) =>
public static Task<Task> WhenAny(Task task1, Task task2) =>
(task1 is null) || (task2 is null) ? throw new ArgumentNullException(task1 is null ? nameof(task1) : nameof(task2)) :
task1.IsCompleted ? FromResult(task1) :
task2.IsCompleted ? FromResult(task2) :
Expand Down Expand Up @@ -6121,7 +6120,6 @@ public static Task<Task<TResult>> WhenAny<TResult>(params Task<TResult>[] tasks)
TaskContinuationOptions.ExecuteSynchronously | TaskContinuationOptions.DenyChildAttach, TaskScheduler.Default);
}

// TODO https://github.com/dotnet/runtime/issues/23021: Make this public.
/// <summary>Creates a task that will complete when either of the supplied tasks have completed.</summary>
/// <param name="task1">The first task to wait on for completion.</param>
/// <param name="task2">The second task to wait on for completion.</param>
Expand All @@ -6133,7 +6131,7 @@ public static Task<Task<TResult>> WhenAny<TResult>(params Task<TResult>[] tasks)
/// <exception cref="System.ArgumentNullException">
/// The <paramref name="task1"/> or <paramref name="task2"/> argument was null.
/// </exception>
internal static Task<Task<TResult>> WhenAny<TResult>(Task<TResult> task1, Task<TResult> task2) =>
public static Task<Task<TResult>> WhenAny<TResult>(Task<TResult> task1, Task<TResult> task2) =>
(task1 is null) || (task2 is null) ? throw new ArgumentNullException(task1 is null ? nameof(task1) : nameof(task2)) :
task1.IsCompleted ? FromResult(task1) :
task2.IsCompleted ? FromResult(task2) :
Expand Down
2 changes: 2 additions & 0 deletions src/libraries/System.Runtime/ref/System.Runtime.cs
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Expand Up @@ -10702,8 +10702,10 @@ public static void WaitAll(System.Threading.Tasks.Task[] tasks, System.Threading
public static System.Threading.Tasks.Task<TResult[]> WhenAll<TResult>(System.Collections.Generic.IEnumerable<System.Threading.Tasks.Task<TResult>> tasks) { throw null; }
public static System.Threading.Tasks.Task<TResult[]> WhenAll<TResult>(params System.Threading.Tasks.Task<TResult>[] tasks) { throw null; }
public static System.Threading.Tasks.Task<System.Threading.Tasks.Task> WhenAny(System.Collections.Generic.IEnumerable<System.Threading.Tasks.Task> tasks) { throw null; }
public static System.Threading.Tasks.Task<System.Threading.Tasks.Task> WhenAny(System.Threading.Tasks.Task task1, System.Threading.Tasks.Task task2) { throw null; }
public static System.Threading.Tasks.Task<System.Threading.Tasks.Task> WhenAny(params System.Threading.Tasks.Task[] tasks) { throw null; }
public static System.Threading.Tasks.Task<System.Threading.Tasks.Task<TResult>> WhenAny<TResult>(System.Collections.Generic.IEnumerable<System.Threading.Tasks.Task<TResult>> tasks) { throw null; }
public static System.Threading.Tasks.Task<System.Threading.Tasks.Task<TResult>> WhenAny<TResult>(System.Threading.Tasks.Task<TResult> task1, System.Threading.Tasks.Task<TResult> task2) { throw null; }
public static System.Threading.Tasks.Task<System.Threading.Tasks.Task<TResult>> WhenAny<TResult>(params System.Threading.Tasks.Task<TResult>[] tasks) { throw null; }
public static System.Runtime.CompilerServices.YieldAwaitable Yield() { throw null; }
}
Expand Down
86 changes: 86 additions & 0 deletions src/libraries/System.Threading.Tasks/tests/MethodCoverage.cs
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Expand Up @@ -179,6 +179,92 @@ public static void TaskWaitAny_WhenAny()
Assert.True(whenAnyVerification, string.Format("The id for whenAny is not correct expected to be {0} or {1} and it is {2}", t11.Id, t21.Id, taskId));
}

[Fact]
public static void Task_WhenAny_TwoTasks_InvalidArgs_Throws()
{
AssertExtensions.Throws<ArgumentNullException>("task1", () => Task.WhenAny(null, Task.CompletedTask));
AssertExtensions.Throws<ArgumentNullException>("task2", () => Task.WhenAny(Task.CompletedTask, null));

AssertExtensions.Throws<ArgumentNullException>("task1", () => Task.WhenAny(null, Task.FromResult(1)));
AssertExtensions.Throws<ArgumentNullException>("task2", () => Task.WhenAny(Task.FromResult(2), null));
}

[Fact]
public static async Task Task_WhenAny_TwoTasks_OnePreCompleted()
{
Task<int> t1 = Task.FromResult(1);
Task<int> t2 = new TaskCompletionSource<int>().Task;

Assert.Same(t1, await Task.WhenAny((Task)t1, (Task)t2));
Assert.Same(t1, await Task.WhenAny((Task)t2, (Task)t1));

Assert.Same(t1, await Task.WhenAny(t1, t2));
Assert.Same(t1, await Task.WhenAny(t2, t1));
}

[Fact]
public static async Task Task_WhenAny_TwoTasks_BothPreCompleted()
{
Task<int> t1 = Task.FromResult(1);
Task<int> t2 = Task.FromResult(2);

Assert.Same(t1, await Task.WhenAny((Task)t1, (Task)t2));
Assert.Same(t1, await Task.WhenAny((Task)t1, (Task)t1));
Assert.Same(t2, await Task.WhenAny((Task)t2, (Task)t1));

Assert.Same(t1, await Task.WhenAny(t1, t2));
Assert.Same(t1, await Task.WhenAny(t1, t1));
Assert.Same(t2, await Task.WhenAny(t2, t1));
}

[Fact]
public static async Task Task_WhenAny_TwoTasks_WakesOnFirstCompletion()
{
// Non-generic, first completes
{
var t1 = new TaskCompletionSource<int>();
var t2 = new TaskCompletionSource<int>();

Task<Task> twa = Task.WhenAny((Task)t1.Task, (Task)t2.Task);
Assert.False(twa.IsCompleted);
t1.SetResult(42);
Assert.Same(t1.Task, await twa);
}

// Generic, first completes
{
var t1 = new TaskCompletionSource<int>();
var t2 = new TaskCompletionSource<int>();

Task<Task<int>> twa = Task.WhenAny(t1.Task, t2.Task);
Assert.False(twa.IsCompleted);
t1.SetResult(42);
Assert.Same(t1.Task, await twa);
}

// Non-generic, second completes
{
var t1 = new TaskCompletionSource<int>();
var t2 = new TaskCompletionSource<int>();

Task<Task> twa = Task.WhenAny((Task)t1.Task, (Task)t2.Task);
Assert.False(twa.IsCompleted);
t2.SetResult(42);
Assert.Same(t2.Task, await twa);
}

// Generic, second completes
{
var t1 = new TaskCompletionSource<int>();
var t2 = new TaskCompletionSource<int>();

Task<Task<int>> twa = Task.WhenAny(t1.Task, t2.Task);
Assert.False(twa.IsCompleted);
t2.SetResult(42);
Assert.Same(t2.Task, await twa);
}
}

[Fact]
public static void CancellationTokenRegitration()
{
Expand Down