feat: added support for AggregateException

Author: woutervanranst

src/WouterVanRanst.Utils.Tests/TaskExtensionsTests.cs

@@ -19,7 +19,7 @@ public async Task ExecuteTasksWithCancellationAsync_ShouldCancelAllTasks_WhenCan
         var t = TaskExtensions.WhenAllWithCancellationAsync(new[] { task1, task2 }, cancellationTokenSource);
 
         // Cancel after a short delay
-        cancellationTokenSource.CancelAfter(100);
+        cancellationTokenSource.CancelAfter(10);
 
         // Assert
         await FluentActions
@@ -38,7 +38,7 @@ public async Task ExecuteTasksWithCancellationAsync_ShouldCancelAllOtherTasks_Wh
         var cancellationTokenSource = new CancellationTokenSource();
         var cancellationToken = cancellationTokenSource.Token;
 
-        var task1 = CreateFaultedTask("Task 1 failed", 500);
+        var task1 = CreateFaultedTask("Task 1 failed", 50);
         var task2 = CreateLongRunningTask(cancellationToken);
 
         // Act
@@ -92,8 +92,8 @@ public async Task ExecuteTasksWithCancellationAsync_ShouldCancelAllOtherTasks_Wh
         var cancellationTokenSource = new CancellationTokenSource();
         var cancellationToken = cancellationTokenSource.Token;
 
-        var task1 = CreateFaultedTask("Task 1 failed", 500);
-        var task2 = CreateFaultedTask("Task 2 failed", 700);
+        var task1 = CreateFaultedTask("Task 1 failed", 50);
+        var task2 = CreateFaultedTask("Task 2 failed", 70);
         var task3 = CreateLongRunningTask(cancellationToken);
 
         // Act
@@ -141,7 +141,7 @@ public async Task ExecuteTasksWithCancellationAsync_ShouldCancelTasks_WhenExtern
         var cancellationTokenSource = new CancellationTokenSource();
         var cancellationToken = cancellationTokenSource.Token;
 
-        var task1 = CreateFaultedTask("Task 1 failed", 500);
+        var task1 = CreateFaultedTask("Task 1 failed", 50);
         var task2 = CreateLongRunningTask(cancellationToken);
 
         // Act: Trigger external cancellation after 500ms
@@ -155,8 +155,32 @@ public async Task ExecuteTasksWithCancellationAsync_ShouldCancelTasks_WhenExtern
         cancellationToken.IsCancellationRequested.Should().BeTrue(); // Ensure cancellation was requested
     }
 
+    [Fact]
+    public async Task ExecuteTasksWithCancellationAsync_ShouldThrowAggregateException_WhenMultipleTasksFault()
+    {
+        // Arrange
+        var cancellationTokenSource = new CancellationTokenSource();
+        var cancellationToken = cancellationTokenSource.Token;
+
+        // Create tasks: Two faulted tasks and one long-running task
+        var task1 = CreateFaultedTask("Task 1 failed", 0);  
+        var task2 = CreateFaultedTask("Task 2 failed", 0); 
+        var task3 = CreateLongRunningTask(cancellationToken);  // Long-running task
 
+        // Act
+        Func<Task> act = async () => await TaskExtensions.WhenAllWithCancellationAsync([task1, task2, task3], cancellationTokenSource);
+
+        // Assert: Expect an AggregateException with both task failures
+        var exception = await act.Should().ThrowAsync<AggregateException>();
+        exception.Which.InnerExceptions.Should().Contain(e => e.Message == "Task 1 failed");
+        exception.Which.InnerExceptions.Should().Contain(e => e.Message == "Task 2 failed");
+
+        // Verify that the long-running task was canceled
+        task3.Status.Should().Be(TaskStatus.Canceled);
+        cancellationTokenSource.IsCancellationRequested.Should().BeTrue();
+    }
 
+    
     private static Task CreateLongRunningTask(CancellationToken cancellationToken)
     {
         return Task.Run(async () =>
@@ -173,7 +197,7 @@ private static Task CreateLongRunningTask(CancellationToken cancellationToken)
         }, cancellationToken);
     }
 
-    private static Task CreateFaultedTask(string exceptionMessage, int delayMs = 500)
+    private static Task CreateFaultedTask(string exceptionMessage, int delayMs)
     {
         return Task.Run(async () =>
         {

src/WouterVanRanst.Utils/Extensions/TaskExtensions.cs

@@ -2,13 +2,17 @@
 
 public static class TaskExtensions
 {
-    public static async Task WhenAllWithCancellationAsync(IEnumerable<Task> tasks, CancellationTokenSource globalCancellationTokenSource)
+    public static async Task WhenAllWithCancellationAsync(IEnumerable<Task> tasks, CancellationTokenSource cancellationTokenSource)
     {
+        tasks = tasks.ToArray();
+
         if (!tasks.Any())
         {
             return;
         }
 
+        Task? t = default;
+
         try
         {
             // Attach faulted continuations to each task to trigger cancellation when any task fails
@@ -19,19 +23,24 @@ public static async Task WhenAllWithCancellationAsync(IEnumerable<Task> tasks, C
                     if (t.IsFaulted)
                     {
                         Console.WriteLine("A task has faulted, cancelling all other tasks.");
-                        globalCancellationTokenSource.Cancel();
+                        cancellationTokenSource.Cancel();
                     }
                 }, TaskContinuationOptions.OnlyOnFaulted);
             }
 
             // Await the completion of all tasks, letting cancellation propagate as necessary
-            await Task.WhenAll(tasks);
+            t = Task.WhenAll(tasks);
+            await t;
         }
         catch
         {
             // If any task faults, ensure cancellation is triggered
-            globalCancellationTokenSource.Cancel();
-            throw;
+            await cancellationTokenSource.CancelAsync();
+
+            if (t?.Exception is not null)
+                throw t.Exception.Flatten();
+            else
+                throw;
         }
     }
 }