feat: Improve reference checking memory leaks runtime tests

src/Uno.UI.RuntimeTests/Tests/Windows_UI_Xaml/Given_FrameworkElement_And_Leak.cs

@@ -1,18 +1,31 @@
-#if !WINDOWS_UWP
+// Uncomment to get additional reference tracking
+// #define TRACK_REFS
+#nullable enable
+
+#if !WINDOWS_UWP
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Linq;
 using System.Runtime.CompilerServices;
+using System.Security.Cryptography.X509Certificates;
 using System.Text;
 using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using Private.Infrastructure;
+using Uno.Extensions;
 using Uno.UI.RuntimeTests.Tests.Windows_UI_Xaml.Controls;
 using Windows.UI.Core;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
 using Windows.UI.Xaml.Controls.Primitives;
 
+#if __MACOS__
+using AppKit;
+#elif __IOS__
+using UIKit;
+#endif
+
 namespace Uno.UI.RuntimeTests.Tests.Windows_UI_Xaml
 {
 	[TestClass]
@@ -44,9 +57,28 @@ public class Given_FrameworkElement_And_Leak
 		[DataRow(typeof(Border), 15)]
 		[DataRow(typeof(ContentControl), 15)]
 		[DataRow(typeof(ContentDialog), 15)]
-		public async Task When_Add_Remove(Type controlType, int count)
+		[DataRow("SamplesApp.Windows_UI_Xaml.Clipping.XamlButtonWithClipping_Scrollable", 15)]
+		[DataRow("Uno.UI.Samples.Content.UITests.ButtonTestsControl.AppBar_KeyBoard", 15)]
+		[DataRow("Uno.UI.Samples.Content.UITests.ButtonTestsControl.Buttons", 15)]
+		public async Task When_Add_Remove(object controlTypeRaw, int count)
 		{
-			var _holders = new ConditionalWeakTable<FrameworkElement, Holder>();
+#if TRACK_REFS
+				var initialInactiveStats = Uno.UI.DataBinding.BinderReferenceHolder.GetInactiveViewReferencesStats();
+				var initialActiveStats = Uno.UI.DataBinding.BinderReferenceHolder.GetReferenceStats();
+#endif
+
+			Type GetType(string s)
+				=> AppDomain.CurrentDomain.GetAssemblies().Select(a => a.GetType(s)).Where(t => t != null).First()!;
+
+			var controlType = controlTypeRaw switch
+			{
+				Type ct => ct,
+				string s => GetType(s),
+				_ => throw new InvalidOperationException()
+			};
+
+			var _holders = new ConditionalWeakTable<DependencyObject, Holder>();
+			void TrackDependencyObject(DependencyObject target) => _holders.Add(target, new Holder(HolderUpdate));
 
 			var maxCounter = 0;
 			var activeControls = 0;
@@ -60,19 +92,11 @@ public async Task When_Add_Remove(Type controlType, int count)
 
 			for (int i = 0; i < count; i++)
 			{
-				var item = Activator.CreateInstance(controlType) as FrameworkElement;
-				_holders.Add(item, new Holder(HolderUpdate));
-				rootContainer.Content = item;
-				await TestServices.WindowHelper.WaitForIdle();
-				rootContainer.Content = null;
-				GC.Collect();
-				GC.WaitForPendingFinalizers();
-
-				// Waiting for idle is required for collection of
-				// DispatcherConditionalDisposable to be executed
-				await TestServices.WindowHelper.WaitForIdle();
+				await MaterializeControl(controlType, _holders, maxCounter, rootContainer);
 			}
 
+			TestServices.WindowHelper.WindowContent = null;
+
 			void HolderUpdate(int value)
 			{
 				_ = rootContainer.Dispatcher.RunAsync(CoreDispatcherPriority.High,
@@ -97,7 +121,96 @@ void HolderUpdate(int value)
 				await TestServices.WindowHelper.WaitForIdle();
 			}
 
+#if TRACK_REFS
+				Uno.UI.DataBinding.BinderReferenceHolder.LogInactiveViewReferencesStatsDiff(initialInactiveStats);
+				Uno.UI.DataBinding.BinderReferenceHolder.LogActiveViewReferencesStatsDiff(initialActiveStats);
+#endif
+
+#if NET5_0
+			if (activeControls != 0)
+			{
+				var retainedTypes = _holders.AsEnumerable().Select(ExtractTargetName).JoinBy(";");
+				Console.WriteLine($"Retained types: {retainedTypes}");
+			}
+#endif
+
 			Assert.AreEqual(0, activeControls);
+
+			static string? ExtractTargetName(KeyValuePair<DependencyObject, Holder> p)
+			{
+				if(p.Key is FrameworkElement fe)
+				{
+					return $"{fe}/{fe.Name}";
+				}
+				else
+				{
+					return p.Key?.ToString();
+				}
+			}
+
+			async Task MaterializeControl(Type controlType, ConditionalWeakTable<DependencyObject, Holder> _holders, int maxCounter, ContentControl rootContainer)
+			{
+				var item = (FrameworkElement)Activator.CreateInstance(controlType);
+				TrackDependencyObject(item);
+				rootContainer.Content = item;
+				await TestServices.WindowHelper.WaitForIdle();
+
+				// Add all children to the tracking
+				foreach (var child in item.EnumerateAllChildren(maxDepth: 200).OfType<UIElement>())
+				{
+					TrackDependencyObject(child);
+
+					if (child is FrameworkElement fe)
+					{
+						// Don't use VisualStateManager.GetVisualStateManager to avoid creating an instance
+						if (child.GetValue(VisualStateManager.VisualStateManagerProperty) is VisualStateManager vsm)
+						{
+							TrackDependencyObject(vsm);
+
+							if (VisualStateManager.GetVisualStateGroups(fe) is { } groups)
+							{
+								foreach (var group in groups)
+								{
+									TrackDependencyObject(group);
+
+									foreach (var transition in group.Transitions)
+									{
+										TrackDependencyObject(transition);
+
+										foreach (var timeline in transition.Storyboard.Children)
+										{
+											TrackDependencyObject(timeline);
+										}
+									}
+
+									foreach (var state in group.States)
+									{
+										TrackDependencyObject(state);
+
+										foreach (var setter in state.Setters)
+										{
+											TrackDependencyObject(setter);
+										}
+
+										foreach (var trigger in state.StateTriggers)
+										{
+											TrackDependencyObject(trigger);
+										}
+									}
+								}
+							}
+						}
+					}
+				}
+
+				rootContainer.Content = null;
+				GC.Collect();
+				GC.WaitForPendingFinalizers();
+
+				// Waiting for idle is required for collection of
+				// DispatcherConditionalDisposable to be executed
+				await TestServices.WindowHelper.WaitForIdle();
+			}
 		}
 
 		[TestMethod]