another failing test for issue #855 and #824

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

@@ -2,7 +2,11 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
+using System.ComponentModel;
 using Avalonia.Controls.Primitives;
+using Avalonia.Controls.Templates;
+using Avalonia.Data;
+using Avalonia.Markup.Xaml.Data;
 using Xunit;
 
 namespace Avalonia.Controls.UnitTests.Primitives
@@ -87,8 +91,93 @@ namespace Avalonia.Controls.UnitTests.Primitives
             Assert.Throws<ArgumentException>(() => target.Value = double.NegativeInfinity);
         }
 
+        [Fact]
+        public void SetValue_Should_Not_Cause_StackOverflow()
+        {
+            var viewModel = new TestStackOverflowViewModel()
+            {
+                Value = 50
+            };
+
+            Track track = null;
+
+            var target = new TestRange()
+            {
+                Template = new FuncControlTemplate<RangeBase>(c =>
+                {
+                    return track = new Track()
+                    {
+                        Width = 100,
+                        Orientation = Orientation.Horizontal,
+                        [~~Track.MinimumProperty] = c[~~RangeBase.MinimumProperty],
+                        [~~Track.MaximumProperty] = c[~~RangeBase.MaximumProperty],
+                        [~~Track.ValueProperty] = c[~~RangeBase.ValueProperty],
+                        Name = "PART_Track",
+                        Thumb = new Thumb()
+                    };
+                }),
+                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
         {
         }
+
+        private class TestStackOverflowViewModel : INotifyPropertyChanged
+        {
+            public int SetterInvokedCount { get; private set; }
+
+            public const int MaxInvokedCount = 1000;
+
+            private double _value;
+
+            public event PropertyChangedEventHandler PropertyChanged;
+
+            public double Value
+            {
+                get { return _value; }
+                set
+                {
+                    if (_value != value)
+                    {
+                        SetterInvokedCount++;
+                        if (SetterInvokedCount < MaxInvokedCount)
+                        {
+                            _value = (int)value;
+                            if (_value > 75) _value = 75;
+                            if (_value < 25) _value = 25;
+                        }
+                        else
+                        {
+                            _value = value;
+                        }
+
+                        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Value)));
+                    }
+                }
+            }
+        }
     }
 }