another test for AvaloniaUI#855 and AvaloniaUI#824 using setter which…

… behind scenes is using weakobservable

tests/Avalonia.Controls.UnitTests/Primitives/RangeBaseTests.cs

@@ -7,6 +7,7 @@
 using Avalonia.Controls.Templates;
 using Avalonia.Data;
 using Avalonia.Markup.Xaml.Data;
+using Avalonia.Styling;
 using Xunit;
 
 namespace Avalonia.Controls.UnitTests.Primitives
@@ -141,6 +142,72 @@ public void SetValue_Should_Not_Cause_StackOverflow()
             Assert.Equal(expected, track.Value);
         }
 
+        [Fact]
+        public void SetValue_Using_Setter_Should_Not_Cause_StackOverflow()
+        {
+            var viewModel = new TestStackOverflowViewModel()
+            {
+                Value = 50
+            };
+
+            Track track = null;
+
+            var target = new TestRange()
+            {
+                Template = new FuncControlTemplate<RangeBase>(c =>
+                {
+                    track = new Track()
+                    {
+                        Width = 100,
+                        Orientation = Orientation.Horizontal,
+                        [~~Track.MinimumProperty] = c[~~RangeBase.MinimumProperty],
+                        [~~Track.MaximumProperty] = c[~~RangeBase.MaximumProperty],
+                        //use setter binding instead to be closer to real world scenario
+                        //as setter is using weakobservable
+                        //[~~Track.ValueProperty] = c[~~RangeBase.ValueProperty],
+                        Name = "PART_Track",
+                        Thumb = new Thumb()
+                    };
+
+                    var s = new Setter()
+                    {
+                        Property = Track.ValueProperty,
+                        Value = new Binding("Value")
+                        {
+                            RelativeSource = new RelativeSource(RelativeSourceMode.TemplatedParent),
+                            Priority = BindingPriority.TemplatedParent,
+                            Mode = BindingMode.TwoWay
+                        }
+                    };
+
+                    s.Apply(null, track, null);
+                    return track;
+                }),
+                Minimum = 0,
+                Maximum = 100,
+                DataContext = viewModel
+            };
+
+            target.Bind(TestRange.ValueProperty, new Binding("Value") { Mode = BindingMode.TwoWay });
+
+            target.ApplyTemplate();
+            track.Measure(new Size(100, 0));
+            track.Arrange(new Rect(0, 0, 100, 0));
+
+            Assert.Equal(1, viewModel.SetterInvokedCount);
+
+            //here in real life stack overflow exception is thrown issue #855 and #824
+            target.Value = 51.001;
+
+            Assert.Equal(2, viewModel.SetterInvokedCount);
+
+            double expected = 51;
+
+            Assert.Equal(expected, viewModel.Value);
+            Assert.Equal(expected, target.Value);
+            Assert.Equal(expected, track.Value);
+        }
+
         private class TestRange : RangeBase
         {
         }