Merge pull request #25896 from sharwell/token-diagnostics

Improve diagnostics when tests fail due to an asynchronous operation timeout

src/EditorFeatures/Core/Tagging/AbstractAsynchronousTaggerProvider.TagSource.cs

@@ -226,7 +226,7 @@ private bool UpToDate
             }
 
             public void RegisterNotification(Action action, int delay, CancellationToken cancellationToken)
-                => _notificationService.RegisterNotification(action, delay, _asyncListener.BeginAsyncOperation("TagSource"), cancellationToken);
+                => _notificationService.RegisterNotification(action, delay, _asyncListener.BeginAsyncOperation(typeof(TTag).Name), cancellationToken);
 
             private void Connect()
             {

src/Workspaces/Core/Portable/Shared/TestHooks/IAsynchronousOperationListenerProvider.cs

@@ -61,11 +61,20 @@ internal sealed class AsynchronousOperationListenerProvider : IAsynchronousOpera
         /// </summary>
         private bool? _enableDiagnosticTokens;
 
+        /// <summary>
+        /// Provides a default value for <see cref="_enableDiagnosticTokens"/>.
+        /// </summary>
+        private static bool? s_enableDiagnosticTokens;
+
         public static void Enable(bool enable)
+            => Enable(enable, diagnostics: null);
+
+        public static void Enable(bool enable, bool? diagnostics)
         {
             // right now, made it static so that one can enable it through reflection easy
             // but we can think of some other way
             s_enabled = enable;
+            s_enableDiagnosticTokens = diagnostics;
         }
 
         [Obsolete("This exported object must be obtained through the MEF export provider.", error: true)]
@@ -192,9 +201,16 @@ private bool DiagnosticTokensEnabled
             {
                 if (!_enableDiagnosticTokens.HasValue)
                 {
-                    // if _trackingBehavior has never been set, check environment variable to see whether it should be enabled.
-                    var enabled = Environment.GetEnvironmentVariable("RoslynWaiterDiagnosticTokenEnabled");
-                    _enableDiagnosticTokens = string.Equals(enabled, "1", StringComparison.OrdinalIgnoreCase) || string.Equals(enabled, "True", StringComparison.OrdinalIgnoreCase);
+                    if (s_enableDiagnosticTokens.HasValue)
+                    {
+                        _enableDiagnosticTokens = s_enableDiagnosticTokens;
+                    }
+                    else
+                    {
+                        // if _enableDiagnosticTokens has never been set, check environment variable to see whether it should be enabled.
+                        var enabled = Environment.GetEnvironmentVariable("RoslynWaiterDiagnosticTokenEnabled");
+                        _enableDiagnosticTokens = string.Equals(enabled, "1", StringComparison.OrdinalIgnoreCase) || string.Equals(enabled, "True", StringComparison.OrdinalIgnoreCase);
+                    }
                 }
 
                 return _enableDiagnosticTokens.Value;

src/Workspaces/CoreTestUtilities/UseExportProviderAttribute.cs

@@ -6,6 +6,7 @@
 using System.Diagnostics;
 using System.Linq;
 using System.Reflection;
+using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using System.Windows.Threading;
@@ -70,7 +71,7 @@ public override void Before(MethodInfo methodUnderTest)
             DesktopMefHostServices.ResetHostServicesTestOnly();
 
             // make sure we enable this for all unit tests
-            AsynchronousOperationListenerProvider.Enable(true);
+            AsynchronousOperationListenerProvider.Enable(enable: true, diagnostics: true);
             ExportProviderCache.SetEnabled_OnlyUseExportProviderAttributeCanCall(true);
         }
 
@@ -112,7 +113,13 @@ public override void After(MethodInfo methodUnderTest)
                         }
                         catch (OperationCanceledException ex) when (timeoutTokenSource.IsCancellationRequested)
                         {
-                            throw new TimeoutException("Failed to clean up listeners in a timely manner.", ex);
+                            var messageBuilder = new StringBuilder("Failed to clean up listeners in a timely manner.");
+                            foreach (var token in ((AsynchronousOperationListenerProvider)listenerProvider).GetTokens())
+                            {
+                                messageBuilder.AppendLine().Append($"  {token}");
+                            }
+
+                            throw new TimeoutException(messageBuilder.ToString(), ex);
                         }
                     }
                 }