From b8683229b9cecbf26ba3c1158edf8b0225a0fff0 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@users.noreply.github.com>
Date: Tue, 6 Feb 2024 21:41:11 +0100
Subject: [PATCH] Fix CompiledBinding with RelativeSource/ElementName but no
 Path (#14514)

* Added failing tests for #14456.

And one passing test.

* Handle converted compiled binding nodes...

...without a path. Previously the `convertedNode` was being discarded if the binding node had no arguments or property value assignments.

Fixes #14456
---
 .../AvaloniaXamlIlBindingPathParser.cs        |  8 +++
 .../CompiledBindingExtensionTests.cs          | 66 +++++++++++++++++++
 2 files changed, 74 insertions(+)

diff --git a/src/Markup/Avalonia.Markup.Xaml.Loader/CompilerExtensions/Transformers/AvaloniaXamlIlBindingPathParser.cs b/src/Markup/Avalonia.Markup.Xaml.Loader/CompilerExtensions/Transformers/AvaloniaXamlIlBindingPathParser.cs
index 736e764aa7c..8173f124d3b 100644
--- a/src/Markup/Avalonia.Markup.Xaml.Loader/CompilerExtensions/Transformers/AvaloniaXamlIlBindingPathParser.cs
+++ b/src/Markup/Avalonia.Markup.Xaml.Loader/CompilerExtensions/Transformers/AvaloniaXamlIlBindingPathParser.cs
@@ -66,8 +66,16 @@ public IXamlAstNode Transform(AstTransformationContext context, IXamlAstNode nod
 
                             bindingPathAssignment.Values[0] = new ParsedBindingPathNode(pathValue, context.GetAvaloniaTypes().CompiledBindingPath, nodes);
                         }
+
+                        foundPath = true;
                     }
                 }
+
+                if (!foundPath && convertedNode != null)
+                {
+                    var nodes = new List<BindingExpressionGrammar.INode> { convertedNode };
+                    binding.Arguments.Add(new ParsedBindingPathNode(binding, context.GetAvaloniaTypes().CompiledBindingPath, nodes));
+                }
             }
 
             return node;
diff --git a/tests/Avalonia.Markup.Xaml.UnitTests/MarkupExtensions/CompiledBindingExtensionTests.cs b/tests/Avalonia.Markup.Xaml.UnitTests/MarkupExtensions/CompiledBindingExtensionTests.cs
index 9d82674fb61..be8b3950ee7 100644
--- a/tests/Avalonia.Markup.Xaml.UnitTests/MarkupExtensions/CompiledBindingExtensionTests.cs
+++ b/tests/Avalonia.Markup.Xaml.UnitTests/MarkupExtensions/CompiledBindingExtensionTests.cs
@@ -824,6 +824,28 @@ public void ResolvesElementNameBindingFromLongForm()
             }
         }
 
+        [Fact]
+        public void ResolvesElementNameBindingFromLongFormWithoutPath()
+        {
+            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.Markup.Xaml.UnitTests.MarkupExtensions;assembly=Avalonia.Markup.Xaml.UnitTests'
+        x:DataType='local:TestDataContext'>
+    <StackPanel>
+        <TextBlock Text='{CompiledBinding StringProperty}' x:Name='text' />
+        <TextBlock Text='{CompiledBinding ElementName=text}' x:Name='text2' />
+    </StackPanel>
+</Window>";
+                var window = (Window)AvaloniaRuntimeXamlLoader.Load(xaml);
+                var textBlock = window.GetControl<TextBlock>("text2");
+
+                Assert.Equal("Avalonia.Controls.TextBlock", textBlock.Text);
+            }
+        }
+
         [Fact]
         public void ResolvesRelativeSourceBindingLongForm()
         {
@@ -1493,6 +1515,28 @@ public void SupportCastToTypeInExpressionWithProperty_ExplicitPropertyCast()
             }
         }
 
+        [Fact]
+        public void Binds_To_Self()
+        {
+            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.Markup.Xaml.UnitTests.MarkupExtensions;assembly=Avalonia.Markup.Xaml.UnitTests'
+        x:DataType='local:TestDataContext'>
+    <TextBlock Name='textBlock' Text='{CompiledBinding $self}' />
+</Window>";
+                var window = (Window)AvaloniaRuntimeXamlLoader.Load(xaml);
+                var textBlock = window.GetControl<TextBlock>("textBlock");
+
+                window.ApplyTemplate();
+                window.Presenter!.ApplyTemplate();
+
+                Assert.Equal("Avalonia.Controls.TextBlock", textBlock.Text);
+            }
+        }
+
         [Fact]
         public void Binds_To_Self_Without_DataType()
         {
@@ -1545,6 +1589,28 @@ public void Binds_To_Self_In_Style()
             }
         }
 
+        [Fact]
+        public void Binds_To_RelativeSource_Self()
+        {
+            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.Markup.Xaml.UnitTests.MarkupExtensions;assembly=Avalonia.Markup.Xaml.UnitTests'
+        x:DataType='local:TestDataContext'>
+    <TextBlock Name='textBlock' Text='{CompiledBinding RelativeSource={RelativeSource Self}}' />
+</Window>";
+                var window = (Window)AvaloniaRuntimeXamlLoader.Load(xaml);
+                var textBlock = window.GetControl<TextBlock>("textBlock");
+
+                window.ApplyTemplate();
+                window.Presenter!.ApplyTemplate();
+
+                Assert.Equal("Avalonia.Controls.TextBlock", textBlock.Text);
+            }
+        }
+
         [Fact]
         public void SupportsMethodBindingAsDelegate()
         {