From 93d2140cc06c6e386d3c6215acef43da9a2e4a5e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bartosz=20Korczy=C5=84ski?= <b.andysc@gmail.com>
Date: Thu, 9 May 2024 13:39:26 +0100
Subject: [PATCH] Wrap type conversions in try-catch to prevent crashes due to
 unhandled exceptions (#15640)

---
 .../Data/Core/TargetTypeConverter.cs          | 36 +++++++++++++++---
 .../TextBoxTests_DataValidation.cs            | 37 +++++++++++++++++++
 2 files changed, 67 insertions(+), 6 deletions(-)

diff --git a/src/Avalonia.Base/Data/Core/TargetTypeConverter.cs b/src/Avalonia.Base/Data/Core/TargetTypeConverter.cs
index 2efc5b42bd..57018bff55 100644
--- a/src/Avalonia.Base/Data/Core/TargetTypeConverter.cs
+++ b/src/Avalonia.Base/Data/Core/TargetTypeConverter.cs
@@ -76,16 +76,32 @@ internal abstract class TargetTypeConverter
 
             if (toTypeConverter.CanConvertFrom(from))
             {
-                result = toTypeConverter.ConvertFrom(null, culture, value);
-                return true;
+                try
+                {
+                    result = toTypeConverter.ConvertFrom(null, culture, value);
+                    return true;
+                }
+                catch
+                {
+                    result = null;
+                    return false;
+                }
             }
 
             var fromTypeConverter = TypeDescriptor.GetConverter(from);
 
             if (fromTypeConverter.CanConvertTo(t))
             {
-                result = fromTypeConverter.ConvertTo(null, culture, value, t);
-                return true;
+                try
+                {
+                    result = fromTypeConverter.ConvertTo(null, culture, value, t);
+                    return true;
+                }
+                catch
+                {
+                    result = null;
+                    return false;
+                }
             }
 
             // TODO: This requires reflection: we probably need to make compiled bindings emit
@@ -95,8 +111,16 @@ internal abstract class TargetTypeConverter
                 t,
                 OperatorType.Implicit | OperatorType.Explicit) is { } cast)
             {
-                result = cast.Invoke(null, new[] { value });
-                return true;
+                try
+                {
+                    result = cast.Invoke(null, new[] { value });
+                    return true;
+                }
+                catch
+                {
+                    result = null;
+                    return false;
+                }
             }
 #pragma warning restore IL2067
 #pragma warning restore IL2026
diff --git a/tests/Avalonia.Controls.UnitTests/TextBoxTests_DataValidation.cs b/tests/Avalonia.Controls.UnitTests/TextBoxTests_DataValidation.cs
index 295fc192d7..0eaa3092e9 100644
--- a/tests/Avalonia.Controls.UnitTests/TextBoxTests_DataValidation.cs
+++ b/tests/Avalonia.Controls.UnitTests/TextBoxTests_DataValidation.cs
@@ -6,8 +6,11 @@ using System.Linq;
 using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Templates;
 using Avalonia.Data;
+using Avalonia.Data.Core;
 using Avalonia.Headless;
 using Avalonia.Markup.Data;
+using Avalonia.Markup.Xaml.MarkupExtensions;
+using Avalonia.Markup.Xaml.MarkupExtensions.CompiledBindings;
 using Avalonia.Platform;
 using Avalonia.UnitTests;
 using Moq;
@@ -110,6 +113,40 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
+        [Fact]
+        public void CompiledBindings_TypeConverter_Exceptions_Should_Set_DataValidationErrors_HasErrors()
+        {
+            var path = new CompiledBindingPathBuilder()
+            .Property(
+                new ClrPropertyInfo(
+                    nameof(ExceptionTest.LessThan10),
+                    target => ((ExceptionTest)target).LessThan10,
+                    (target, value) => ((ExceptionTest)target).LessThan10 = (int)value,
+                    typeof(int)),
+                PropertyInfoAccessorFactory.CreateInpcPropertyAccessor)
+            .Build();
+
+            using (UnitTestApplication.Start(Services))
+            {
+                var target = new TextBox
+                {
+                    DataContext = new ExceptionTest(),
+                    [!TextBox.TextProperty] = new CompiledBindingExtension
+                    {
+                        Source = new ExceptionTest(),
+                        Path = path,
+                        Mode = BindingMode.TwoWay
+                    },
+                    Template = CreateTemplate(),
+                };
+
+                target.ApplyTemplate();
+
+                target.Text = "a";
+                Assert.True(DataValidationErrors.GetHasErrors(target));
+            }
+        }
+
         private static TestServices Services => TestServices.MockThreadingInterface.With(
             standardCursorFactory: Mock.Of<ICursorFactory>(),
             textShaperImpl: new HeadlessTextShaperStub(),