feat (TaskCompletionSourceRCA.cs): introduce this new utility class w…

…hich ensures that the TaskCreationOptions.RunContinuationsAsynchronously is turned on for all constructors - also employ it in all operations

Laerdal.McuMgr.Tests/FileDownloader/FileDownloaderTestbed.SingleFileDownloadAsync.ShouldThrowAllDownloadAttemptsFailedException_GivenRogueNativeErrorMessage.cs

@@ -26,8 +26,8 @@ public async Task SingleFileDownloadAsync_ShouldThrowAllDownloadAttemptsFailedEx
 
             var mockedNativeFileDownloaderProxy = new MockedErroneousNativeFileDownloaderProxySpy13(
                 mockedFileData: mockedFileData,
-                downloaderCallbacksProxy: new GenericNativeFileDownloaderCallbacksProxy_(),
-                rogueNativeErrorMessage: nativeRogueErrorMessage
+                rogueNativeErrorMessage: nativeRogueErrorMessage,
+                downloaderCallbacksProxy: new GenericNativeFileDownloaderCallbacksProxy_()
             );
             var fileDownloader = new McuMgr.FileDownloader.FileDownloader(mockedNativeFileDownloaderProxy);
 
@@ -44,8 +44,7 @@ public async Task SingleFileDownloadAsync_ShouldThrowAllDownloadAttemptsFailedEx
             ));
 
             // Assert
-            await work.Should()
-                .ThrowWithinAsync<AllDownloadAttemptsFailedException>(3.Seconds());
+            await work.Should().ThrowWithinAsync<AllDownloadAttemptsFailedException>(3.Seconds());
 
             mockedNativeFileDownloaderProxy.CancelCalled.Should().BeFalse();
             mockedNativeFileDownloaderProxy.DisconnectCalled.Should().BeFalse(); //00

Laerdal.McuMgr/Shared/Common/Helpers/TaskCompletionSourceRCA.cs

@@ -0,0 +1,92 @@
+using System.Threading.Tasks;
+
+namespace Laerdal.McuMgr.Common.Helpers
+{
+    /// <summary>Like <see cref="TaskCompletionSource"/> but with <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> turned on by default in all constructors.</summary>
+    /// <remarks>
+    /// Inspired by <see href="https://devblogs.microsoft.com/premier-developer/the-danger-of-taskcompletionsourcet-class/">Microsoft's recommendation on TCS</see> which strongly
+    /// advises using <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> with <see cref="TaskCompletionSource"/> to avoid exotic deadlocks in certain corner-cases.
+    /// </remarks>
+    internal sealed class TaskCompletionSourceRCA : TaskCompletionSource
+    {
+        /// <summary>Like <see cref="TaskCompletionSource"/> but with the <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> turned on by default in all constructors.</summary>
+        /// <remarks>
+        /// Inspired by <see href="https://devblogs.microsoft.com/premier-developer/the-danger-of-taskcompletionsourcet-class/">Microsoft's recommendation on TCS</see> which strongly
+        /// advises using <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> with <see cref="TaskCompletionSource"/> to avoid exotic deadlocks in certain corner-cases.
+        /// </remarks>
+        public TaskCompletionSourceRCA() : base(TaskCreationOptions.RunContinuationsAsynchronously)
+        {
+        }
+
+        /// <summary>Like <see cref="TaskCompletionSource"/> but with <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> turned on by default in all constructors.</summary>
+        /// <remarks>
+        /// Inspired by <see href="https://devblogs.microsoft.com/premier-developer/the-danger-of-taskcompletionsourcet-class/">Microsoft's recommendation on TCS</see> which strongly
+        /// advises using <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> with <see cref="TaskCompletionSource"/> to avoid exotic deadlocks in certain corner-cases.
+        /// </remarks>
+        public TaskCompletionSourceRCA(object state) : base(state, TaskCreationOptions.RunContinuationsAsynchronously)
+        {
+        }
+
+        /// <summary>Like <see cref="TaskCompletionSource"/> but with <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> turned on by default in all constructors.</summary>
+        /// <remarks>
+        /// Inspired by <see href="https://devblogs.microsoft.com/premier-developer/the-danger-of-taskcompletionsourcet-class/">Microsoft's recommendation on TCS</see> which strongly
+        /// advises using <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> with <see cref="TaskCompletionSource"/> to avoid exotic deadlocks in certain corner-cases.
+        /// </remarks>
+        public TaskCompletionSourceRCA(object state, TaskCreationOptions creationOptions) : base(state, creationOptions | TaskCreationOptions.RunContinuationsAsynchronously)
+        {
+        }
+
+        /// <summary>Like <see cref="TaskCompletionSource"/> but with <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> turned on by default in all constructors.</summary>
+        /// <remarks>
+        /// Inspired by <see href="https://devblogs.microsoft.com/premier-developer/the-danger-of-taskcompletionsourcet-class/">Microsoft's recommendation on TCS</see> which strongly
+        /// advises using <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> with <see cref="TaskCompletionSource"/> to avoid exotic deadlocks in certain corner-cases.
+        /// </remarks>
+        public TaskCompletionSourceRCA(TaskCreationOptions creationOptions) : base(creationOptions | TaskCreationOptions.RunContinuationsAsynchronously)
+        {
+        }
+    }
+
+    /// <summary>Like <see cref="TaskCompletionSource{T}"/> but with <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> turned on by default in all constructors.</summary>
+    /// <remarks>
+    /// Inspired by <see href="https://devblogs.microsoft.com/premier-developer/the-danger-of-taskcompletionsourcet-class/">Microsoft's recommendation on TCS</see> which strongly
+    /// advises using <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> with <see cref="TaskCompletionSource{T}"/> to avoid exotic deadlocks in certain corner-cases.
+    /// </remarks>
+    internal sealed class TaskCompletionSourceRCA<T> : TaskCompletionSource<T>
+    {
+        /// <summary>Like <see cref="TaskCompletionSource{T}"/> but with the <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> turned on by default in all constructors.</summary>
+        /// <remarks>
+        /// Inspired by <see href="https://devblogs.microsoft.com/premier-developer/the-danger-of-taskcompletionsourcet-class/">Microsoft's recommendation on TCS</see> which strongly
+        /// advises using <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> with <see cref="TaskCompletionSource{T}"/> to avoid exotic deadlocks in certain corner-cases.
+        /// </remarks>
+        public TaskCompletionSourceRCA() : base(TaskCreationOptions.RunContinuationsAsynchronously)
+        {
+        }
+
+        /// <summary>Like <see cref="TaskCompletionSource{T}"/> but with <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> turned on by default in all constructors.</summary>
+        /// <remarks>
+        /// Inspired by <see href="https://devblogs.microsoft.com/premier-developer/the-danger-of-taskcompletionsourcet-class/">Microsoft's recommendation on TCS</see> which strongly
+        /// advises using <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> with <see cref="TaskCompletionSource{T}"/> to avoid exotic deadlocks in certain corner-cases.
+        /// </remarks>
+        public TaskCompletionSourceRCA(object state) : base(state, TaskCreationOptions.RunContinuationsAsynchronously)
+        {
+        }
+
+        /// <summary>Like <see cref="TaskCompletionSource{T}"/> but with <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> turned on by default in all constructors.</summary>
+        /// <remarks>
+        /// Inspired by <see href="https://devblogs.microsoft.com/premier-developer/the-danger-of-taskcompletionsourcet-class/">Microsoft's recommendation on TCS</see> which strongly
+        /// advises using <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> with <see cref="TaskCompletionSource{T}"/> to avoid exotic deadlocks in certain corner-cases.
+        /// </remarks>
+        public TaskCompletionSourceRCA(object state, TaskCreationOptions creationOptions) : base(state, creationOptions | TaskCreationOptions.RunContinuationsAsynchronously)
+        {
+        }
+
+        /// <summary>Like <see cref="TaskCompletionSource{T}"/> but with <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> turned on by default in all constructors.</summary>
+        /// <remarks>
+        /// Inspired by <see href="https://devblogs.microsoft.com/premier-developer/the-danger-of-taskcompletionsourcet-class/">Microsoft's recommendation on TCS</see> which strongly
+        /// advises using <see cref="TaskCreationOptions"/>.<see cref="TaskCreationOptions.RunContinuationsAsynchronously"/> with <see cref="TaskCompletionSource{T}"/> to avoid exotic deadlocks in certain corner-cases.
+        /// </remarks>
+        public TaskCompletionSourceRCA(TaskCreationOptions creationOptions) : base(creationOptions | TaskCreationOptions.RunContinuationsAsynchronously)
+        {
+        }
+    }
+}

Laerdal.McuMgr/Shared/DeviceResetter/DeviceResetter.cs

@@ -98,7 +98,7 @@ public event EventHandler<StateChangedEventArgs> StateChanged
 
         public async Task ResetAsync(int timeoutInMs = -1)
         {
-            var taskCompletionSource = new TaskCompletionSource<bool>(state: false);
+            var taskCompletionSource = new TaskCompletionSourceRCA<bool>(state: false);
 
             try
             {

Laerdal.McuMgr/Shared/FileDownloader/FileDownloader.cs

@@ -240,7 +240,7 @@ public async Task<byte[]> DownloadAsync(
             var didWarnOnceAboutUnstableConnection = false;
             for (var triesCount = 1; !isCancellationRequested;)
             {
-                var taskCompletionSource = new TaskCompletionSource<byte[]>(state: null);
+                var taskCompletionSource = new TaskCompletionSourceRCA<byte[]>(state: null);
 
                 try
                 {
@@ -344,6 +344,8 @@ ex is not ArgumentException //10 wops probably missing native lib symbols!
                 }
                 finally
                 {
+                    taskCompletionSource.TrySetCanceled(); //it is best to ensure that the task is fossilized in case of rogue exceptions
+
                     Cancelled -= FileDownloader_Cancelled_;
                     StateChanged -= FileDownloader_StateChanged_;
                     DownloadCompleted -= FileDownloader_DownloadCompleted_;

Laerdal.McuMgr/Shared/FileUploader/FileUploader.cs

@@ -299,7 +299,7 @@ public async Task UploadAsync<TData>(
             var didWarnOnceAboutUnstableConnection = false;
             for (var triesCount = 1; !isCancellationRequested;)
             {
-                var taskCompletionSource = new TaskCompletionSource<bool>(state: false);
+                var taskCompletionSource = new TaskCompletionSourceRCA<bool>(state: false);
                 try
                 {
                     Cancelled += FileUploader_Cancelled_;

Laerdal.McuMgr/Shared/FirmwareEraser/FirmwareEraser.cs

@@ -114,7 +114,7 @@ public event EventHandler<FatalErrorOccurredEventArgs> FatalErrorOccurred
 
         public async Task EraseAsync(int imageIndex = 1, int timeoutInMs = -1)
         {
-            var taskCompletionSource = new TaskCompletionSource<bool>(state: false);
+            var taskCompletionSource = new TaskCompletionSourceRCA<bool>(state: false);
 
             try
             {

Laerdal.McuMgr/Shared/FirmwareInstaller/FirmwareInstaller.cs

@@ -213,7 +213,7 @@ public async Task InstallAsync(
             var didWarnOnceAboutUnstableConnection = false;
             for (var triesCount = 1; !isCancellationRequested;)
             {
-                var taskCompletionSource = new TaskCompletionSource<bool>(state: false);
+                var taskCompletionSource = new TaskCompletionSourceRCA<bool>(state: false);
                 try
                 {
                     Cancelled += FirmwareInstaller_Cancelled_;