Revert "Merge pull request AvaloniaUI#8189 from AvaloniaUI/fixes/8178…

…-elementname-binding-leak"

This reverts commit 20ed002.

src/Avalonia.Base/Collections/Pooled/PooledList.cs

@@ -587,7 +587,7 @@ public void Clear()
             if (size > 0 && _clearOnFree)
             {
                 // Clear the elements so that the gc can reclaim the references.
-                Array.Clear(_items, 0, size);
+                Array.Clear(_items, 0, _size);
             }
         }
 

src/Avalonia.Base/Data/Core/Plugins/AvaloniaPropertyAccessorPlugin.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Runtime.ExceptionServices;
-using Avalonia.Utilities;
 
 namespace Avalonia.Data.Core.Plugins
 {
@@ -61,10 +60,11 @@ public bool Match(object obj, string propertyName)
             return AvaloniaPropertyRegistry.Instance.FindRegistered(o, propertyName);
         }
 
-        private class Accessor : PropertyAccessorBase, IWeakEventSubscriber<AvaloniaPropertyChangedEventArgs>
+        private class Accessor : PropertyAccessorBase, IObserver<object?>
         {
             private readonly WeakReference<AvaloniaObject> _reference;
             private readonly AvaloniaProperty _property;
+            private IDisposable? _subscription;
 
             public Accessor(WeakReference<AvaloniaObject> reference, AvaloniaProperty property)
             {
@@ -95,45 +95,29 @@ public override bool SetValue(object? value, BindingPriority priority)
                 return false;
             }
 
-            void IWeakEventSubscriber<AvaloniaPropertyChangedEventArgs>.
-                OnEvent(object? notifyPropertyChanged, WeakEvent ev, AvaloniaPropertyChangedEventArgs e)
-            {
-                if (e.Property == _property)
-                {
-                    SendCurrentValue();
-                }
-            }
-
             protected override void SubscribeCore()
             {
-                SubscribeToChanges();
-                SendCurrentValue();
+                _subscription = Instance?.GetObservable(_property).Subscribe(this);
             }
 
             protected override void UnsubscribeCore()
             {
-                var instance = Instance;
-
-                if (instance != null)
-                    WeakEvents.AvaloniaPropertyChanged.Unsubscribe(instance, this);
+                _subscription?.Dispose();
+                _subscription = null;
             }
 
-            private void SendCurrentValue()
+            void IObserver<object?>.OnCompleted()
             {
-                try
-                {
-                    var value = Value;
-                    PublishValue(value);
-                }
-                catch { }
             }
 
-            private void SubscribeToChanges()
+            void IObserver<object?>.OnError(Exception error)
             {
-                var instance = Instance;
+                ExceptionDispatchInfo.Capture(error).Throw();
+            }
 
-                if (instance != null)
-                    WeakEvents.AvaloniaPropertyChanged.Subscribe(instance, this);
+            void IObserver<object?>.OnNext(object? value)
+            {
+                PublishValue(value);
             }
         }
     }

src/Avalonia.Base/Utilities/WeakEvents.cs

@@ -31,23 +31,10 @@ public static readonly WeakEvent<INotifyPropertyChanged, PropertyChangedEventArg
                 return () => s.PropertyChanged -= handler;
             });
 
-
-    /// <summary>
-    /// Represents PropertyChanged event from <see cref="AvaloniaObject"/>
-    /// </summary>
-    public static readonly WeakEvent<AvaloniaObject, AvaloniaPropertyChangedEventArgs>
-        AvaloniaPropertyChanged = WeakEvent.Register<AvaloniaObject, AvaloniaPropertyChangedEventArgs>(
-            (s, h) =>
-            {
-                EventHandler<AvaloniaPropertyChangedEventArgs> handler = (_, e) => h(s, e);
-                s.PropertyChanged += handler;
-                return () => s.PropertyChanged -= handler;
-            });
-
     /// <summary>
     /// Represents CanExecuteChanged event from <see cref="ICommand"/>
     /// </summary>
     public static readonly WeakEvent<ICommand, EventArgs> CommandCanExecuteChanged =
         WeakEvent.Register<ICommand>((s, h) => s.CanExecuteChanged += h,
             (s, h) => s.CanExecuteChanged -= h);
-}
+}

tests/Avalonia.LeakTests/ControlTests.cs

@@ -2,18 +2,17 @@
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Linq;
-using System.Reactive.Disposables;
+using System.Runtime.Remoting.Contexts;
 using Avalonia.Controls;
 using Avalonia.Controls.Shapes;
 using Avalonia.Controls.Templates;
-using Avalonia.Data;
 using Avalonia.Diagnostics;
 using Avalonia.Input;
+using Avalonia.Layout;
 using Avalonia.Media;
 using Avalonia.Platform;
 using Avalonia.Rendering;
 using Avalonia.Styling;
-using Avalonia.Threading;
 using Avalonia.UnitTests;
 using Avalonia.VisualTree;
 using JetBrains.dotMemoryUnit;
@@ -621,96 +620,14 @@ public void ItemsRepeater_Is_Freed()
             }
         }
 
-        [Fact]
-        public void ElementName_Binding_In_DataTemplate_Is_Freed()
-        {
-            using (Start())
-            {
-                var items = new ObservableCollection<int>(Enumerable.Range(0, 10));
-                NameScope ns;
-                TextBox tb;
-                ListBox lb;
-                var window = new Window
-                {
-                    [NameScope.NameScopeProperty] = ns = new NameScope(),
-                    Width = 100,
-                    Height = 100,
-                    Content = new StackPanel
-                    {
-                        Children =
-                        {
-                            (tb = new TextBox
-                            {
-                                Name = "tb",
-                                Text = "foo",
-                            }),
-                            (lb = new ListBox
-                            {
-                                Items = items,
-                                ItemTemplate = new FuncDataTemplate<int>((_, _) =>
-                                    new Canvas
-                                    {
-                                        Width = 10,
-                                        Height = 10,
-                                        [!Control.TagProperty] = new Binding
-                                        {
-                                            ElementName = "tb",
-                                            Path = "Text",
-                                            NameScope = new WeakReference<INameScope>(ns),
-                                        }
-                                    })
-                            }),
-                        }
-                    }
-                };
-
-                tb.RegisterInNameScope(ns);
-
-                window.Show();
-                window.LayoutManager.ExecuteInitialLayoutPass();
-
-                void AssertInitialItemState()
-                {
-                    var item0 = (ListBoxItem)lb.ItemContainerGenerator.Containers.First().ContainerControl;
-                    var canvas0 = (Canvas)item0.Presenter.Child;
-                    Assert.Equal("foo", canvas0.Tag);
-                }
-
-                Assert.Equal(10, lb.ItemContainerGenerator.Containers.Count());
-                AssertInitialItemState();
-
-                items.Clear();
-                window.LayoutManager.ExecuteLayoutPass();
-
-                Assert.Empty(lb.ItemContainerGenerator.Containers);
-
-                dotMemory.Check(memory =>
-                    Assert.Equal(0, memory.GetObjects(where => where.Type.Is<Canvas>()).ObjectsCount));
-            }
-        }
-
         private IDisposable Start()
         {
-            void Cleanup()
-            {
-                // KeyboardDevice holds a reference to the focused item.
-                KeyboardDevice.Instance.SetFocusedElement(null, NavigationMethod.Unspecified, KeyModifiers.None);
-
-                // Empty the dispatcher queue.
-                Dispatcher.UIThread.RunJobs();
-            }
-
-            return new CompositeDisposable
-            {
-                Disposable.Create(Cleanup),
-                UnitTestApplication.Start(TestServices.StyledWindow.With(
-                    focusManager: new FocusManager(),
-                    keyboardDevice: () => new KeyboardDevice(),
-                    inputManager: new InputManager()))
-            };
+            return UnitTestApplication.Start(TestServices.StyledWindow.With(
+                focusManager: new FocusManager(),
+                keyboardDevice: () => new KeyboardDevice(),
+                inputManager: new InputManager()));
         }
 
-
         private class Node
         {
             public string Name { get; set; }