add failing test

tests/Avalonia.Base.UnitTests/Avalonia.Base.UnitTests.csproj

@@ -14,6 +14,7 @@
   <Import Project="..\..\build\SharedVersion.props" />
   <ItemGroup>
     <ProjectReference Include="..\..\src\Avalonia.Base\Avalonia.Base.csproj" />
+    <ProjectReference Include="..\..\src\Markup\Avalonia.Markup.Xaml.Loader\Avalonia.Markup.Xaml.Loader.csproj" />
     <ProjectReference Include="..\Avalonia.UnitTests\Avalonia.UnitTests.csproj" />
   </ItemGroup>
   <ItemGroup>

tests/Avalonia.Base.UnitTests/Logging/LoggingTests.cs

@@ -0,0 +1,214 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using Avalonia.Controls;
+using Avalonia.Controls.Shapes;
+using Avalonia.Logging;
+using Avalonia.Markup.Xaml;
+using Avalonia.UnitTests;
+using Avalonia.Utilities;
+using Xunit;
+
+namespace Avalonia.Base.UnitTests.Logging
+{
+    public class LoggingTests
+    {
+        [Fact]
+        public void Control_Should_Not_Log_Binding_Errors_When_Detached_From_Visual_Tree()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+        xmlns:local='clr-namespace:Avalonia.Base.UnitTests.Logging;assembly=Avalonia.UnitTests'>
+    <Panel Name='panel'>
+    <Rectangle Name='rect' Fill='{Binding $parent[Window].Background}'/>
+  </Panel>
+</Window>";
+
+                var window = (Window)AvaloniaRuntimeXamlLoader.Load(xaml);
+                using var logSink = new StubLogSink(LogEventLevel.Warning);
+                var panel = window.FindControl<Panel>("panel");
+                var rect = window.FindControl<Rectangle>("rect");
+                window.ApplyTemplate();
+                window.Presenter.ApplyTemplate();
+                panel.Children.Remove(rect);
+                Assert.Equal(0, logSink.Results.Count);
+            }
+        }
+    } 
+
+    class StubLogSink : ILogSink, IDisposable
+    {
+        LogEventLevel _level;
+        public StubLogSink(LogEventLevel level)
+        {
+            _level = level;
+            Logger.Sink = this;
+        }
+        public void Dispose()
+        {
+            Logger.Sink = null;
+        }
+        public List<string> Results { get; set; } = new List<string>();
+
+        public bool IsEnabled(LogEventLevel level, string area)
+        {
+            return true;
+        }
+
+        public void Log(LogEventLevel level, string area, object source, string messageTemplate)
+        {
+            if (level >= _level)
+            {
+                Results.Add(Format<object, object, object>(area, messageTemplate, source));
+            }
+        }
+
+        public void Log<T0>(LogEventLevel level, string area, object source, string messageTemplate, T0 propertyValue0)
+        {
+            if (level >= _level)
+            {
+                Results.Add(Format<T0, object, object>(area, messageTemplate, source, propertyValue0));
+            }
+        }
+
+        public void Log<T0, T1>(LogEventLevel level, string area, object source, string messageTemplate, T0 propertyValue0, T1 propertyValue1)
+        {
+            if (level >= _level)
+            {
+                Results.Add(Format<T0, T1, object>(area, messageTemplate, source, propertyValue0, propertyValue1));
+            }
+        }
+
+        public void Log<T0, T1, T2>(LogEventLevel level, string area, object source, string messageTemplate, T0 propertyValue0, T1 propertyValue1, T2 propertyValue2)
+        {
+            if (level >= _level)
+            {
+                Results.Add(Format(area, messageTemplate, source, propertyValue0, propertyValue1, propertyValue2));
+            }
+        }
+
+        public void Log(LogEventLevel level, string area, object source, string messageTemplate, params object[] propertyValues)
+        {
+            if (level >= _level)
+            {
+                Results.Add(Format(area, messageTemplate, source, propertyValues));
+            }
+        }
+        #region Copy-Pasta
+        private static string Format<T0, T1, T2>(
+           string area,
+           string template,
+           object source,
+           T0 v0 = default,
+           T1 v1 = default,
+           T2 v2 = default)
+        {
+            var result = new StringBuilder(template.Length);
+            var r = new CharacterReader(template.AsSpan());
+            var i = 0;
+
+            result.Append('[');
+            result.Append(area);
+            result.Append("] ");
+
+            while (!r.End)
+            {
+                var c = r.Take();
+
+                if (c != '{')
+                {
+                    result.Append(c);
+                }
+                else
+                {
+                    if (r.Peek != '{')
+                    {
+                        result.Append('\'');
+                        result.Append(i++ switch
+                        {
+                            0 => v0,
+                            1 => v1,
+                            2 => v2,
+                            _ => null
+                        });
+                        result.Append('\'');
+                        r.TakeUntil('}');
+                        r.Take();
+                    }
+                    else
+                    {
+                        result.Append('{');
+                        r.Take();
+                    }
+                }
+            }
+
+            if (source is object)
+            {
+                result.Append(" (");
+                result.Append(source.GetType().Name);
+                result.Append(" #");
+                result.Append(source.GetHashCode());
+                result.Append(')');
+            }
+
+            return result.ToString();
+        }
+
+        private static string Format(
+            string area,
+            string template,
+            object source,
+            object[] v)
+        {
+            var result = new StringBuilder(template.Length);
+            var r = new CharacterReader(template.AsSpan());
+            var i = 0;
+
+            result.Append('[');
+            result.Append(area);
+            result.Append(']');
+
+            while (!r.End)
+            {
+                var c = r.Take();
+
+                if (c != '{')
+                {
+                    result.Append(c);
+                }
+                else
+                {
+                    if (r.Peek != '{')
+                    {
+                        result.Append('\'');
+                        result.Append(i < v.Length ? v[i++] : null);
+                        result.Append('\'');
+                        r.TakeUntil('}');
+                        r.Take();
+                    }
+                    else
+                    {
+                        result.Append('{');
+                        r.Take();
+                    }
+                }
+            }
+
+            if (source is object)
+            {
+                result.Append('(');
+                result.Append(source.GetType().Name);
+                result.Append(" #");
+                result.Append(source.GetHashCode());
+                result.Append(')');
+            }
+
+            return result.ToString();
+        }
+        #endregion
+    }
+}