Add Edge Case Test GenerateBindableProperty_WithBothInitializerAndDefault_GeneratedCodeDefaultsToUseDefaultValueCreatorMethod

Author: TheCodeTraveler

src/CommunityToolkit.Maui.SourceGenerators.Internal.UnitTests/BindablePropertyAttributeSourceGeneratorTests/EdgeCaseTests.cs

@@ -456,4 +456,51 @@ public partial class {{defaultTestClassName}}
 
 		await VerifySourceGeneratorAsync(source, expectedGenerated);
 	}
+
+	[Fact]
+	public async Task GenerateBindableProperty_WithBothInitializerAndDefault_GeneratedCodeDefaultsToUseDefaultValueCreatorMethod()
+	{
+		const string source =
+			/* language=C#-test */
+			//lang=csharp
+			$$"""
+			using CommunityToolkit.Maui;
+			using Microsoft.Maui.Controls;
+			using System;
+
+			namespace {{defaultTestNamespace}};
+
+			public partial class {{defaultTestClassName}} : View
+			{
+			    [BindablePropertyAttribute(DefaultValueCreatorMethodName = nameof(CreateDefaultText))]
+			    public partial string Text { get; set; } = "Initial Value";
+
+				static string CreateDefaultText(BindableObject bindable)
+				{
+					return "Initial Value";
+				}
+			}
+			""";
+
+		const string expectedGenerated =
+			/* language=C#-test */
+			//lang=csharp
+			$$"""
+			// <auto-generated>
+			// See: CommunityToolkit.Maui.SourceGenerators.Internal.BindablePropertyAttributeSourceGenerator
+			#pragma warning disable
+			#nullable enable
+			namespace {{defaultTestNamespace}};
+			public partial class {{defaultTestClassName}}
+			{
+			    /// <summary>
+			    /// Backing BindableProperty for the <see cref = "Text"/> property.
+			    /// </summary>
+			    public static readonly global::Microsoft.Maui.Controls.BindableProperty TextProperty = global::Microsoft.Maui.Controls.BindableProperty.Create("Text", typeof(string), typeof({{defaultTestNamespace}}.{{defaultTestClassName}}), null, Microsoft.Maui.Controls.BindingMode.OneWay, null, null, null, null, CreateDefaultText);
+			    public partial string Text { get => false ? field : (string)GetValue(TextProperty); set => SetValue(TextProperty, value); }
+			}
+			""";
+
+		await VerifySourceGeneratorAsync(source, expectedGenerated);
+	}
 }

src/CommunityToolkit.Maui.SourceGenerators.Internal/Generators/BindablePropertyAttributeSourceGenerator.cs

@@ -183,7 +183,7 @@ static string GenerateSource(SemanticValues value)
 				GenerateBindableProperty(sb, in info);
 			}
 
-			if (info.HasInitializer)
+			if (info.ShouldUsePropertyInitializer)
 			{
 				GenerateInitializingProperty(sb, in info);
 				GenerateDefaultValueMethod(sb, in info, classNameWithGenerics);
@@ -320,8 +320,16 @@ static void GenerateProperty(StringBuilder sb, in BindablePropertyModel info)
 
 		if (info.HasInitializer)
 		{
-			sb.Append(info.InitializingPropertyName)
-				.Append(" ? field : ");
+			if (info.ShouldUsePropertyInitializer)
+			{
+				sb.Append(info.InitializingPropertyName);
+			}
+			else
+			{
+				sb.Append("false");
+			}
+
+			sb.Append(" ? field : ");
 		}
 
 		sb.Append("(")

src/CommunityToolkit.Maui.SourceGenerators.Internal/Models/Records.cs

@@ -5,10 +5,13 @@ namespace CommunityToolkit.Maui.SourceGenerators.Internal.Models;
 
 record BindablePropertyModel(string PropertyName, ITypeSymbol ReturnType, ITypeSymbol DeclaringType, string DefaultValue, string DefaultBindingMode, string ValidateValueMethodName, string PropertyChangedMethodName, string PropertyChangingMethodName, string CoerceValueMethodName, string DefaultValueCreatorMethodName, string NewKeywordText, bool IsReadOnlyBindableProperty, string? SetterAccessibility, bool HasInitializer)
 {
+	// When both a DefaultValueCreatorMethodName and an initializer are provided, we implement the DefaultValueCreator method and the ignore the partial Property initializer
+	public bool ShouldUsePropertyInitializer => HasInitializer && string.IsNullOrEmpty(DefaultValueCreatorMethodName);
 	public string BindablePropertyName => $"{PropertyName}Property";
 	public string BindablePropertyKeyName => $"{char.ToLower(PropertyName[0])}{PropertyName[1..]}PropertyKey";
-	public string EffectiveDefaultValueCreatorMethodName => HasInitializer ? $"__createDefault{PropertyName}" : DefaultValueCreatorMethodName;
+	public string EffectiveDefaultValueCreatorMethodName => ShouldUsePropertyInitializer ? $"__createDefault{PropertyName}" : DefaultValueCreatorMethodName;
 	public string InitializingPropertyName => $"__initializing{PropertyName}";
+
 }
 
 record SemanticValues(ClassInformation ClassInformation, EquatableArray<BindablePropertyModel> BindableProperties);