// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics;
using System.Runtime.CompilerServices;

namespace System.Threading.Tasks
{
#if TESTUTILS
    public
#else
    internal
#endif
    static class TaskExtensions
    {
        public static async Task OrThrowIfOtherFails(this Task task, Task otherTask)
        {
            var completed = await Task.WhenAny(task, otherTask);
            if (completed == otherTask && otherTask.IsFaulted)
            {
                // Manifest the exception
                otherTask.GetAwaiter().GetResult();
                throw new Exception("Unreachable code");
            }
            else
            {
                // Await the task we were asked to await. Either it's finished, or the otherTask finished successfully, and it's not our job to check that
                await task;
            }
        }

        public static async Task<T> OrThrowIfOtherFails<T>(this Task<T> task, Task otherTask)
        {
            await OrThrowIfOtherFails((Task)task, otherTask);

            // If we get here, 'task' is finished and succeeded.
            return task.GetAwaiter().GetResult();
        }
    }
}
