Refactor Animations to use [BindableProperty] partial properties

src/CommunityToolkit.Maui.Core/Primitives/Defaults/BaseAnimationDefaults.cs

@@ -0,0 +1,7 @@
+namespace CommunityToolkit.Maui.Core;
+
+static class BaseAnimationDefaults
+{
+	public const uint Length = 250u;
+	public static Easing Easing { get; } = Easing.Linear;
+}

src/CommunityToolkit.Maui.Core/Primitives/Defaults/FadeAnimationDefaults.cs

@@ -0,0 +1,7 @@
+namespace CommunityToolkit.Maui.Core;
+
+static class FadeAnimationDefaults
+{
+	public const uint Length = 300u;
+	public const double Opacity = 0.3;
+}

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

@@ -610,7 +610,7 @@ public partial class {{defaultTestClassName}}
 
 			file static class __{{defaultTestClassName}}BindablePropertyInitHelpers
 			{
-			    public static bool IsInitializingText = false;
+			    public static volatile bool IsInitializingText = false;
 			    public static object CreateDefaultText(global::Microsoft.Maui.Controls.BindableObject bindable)
 			    {
 			        IsInitializingText = true;
@@ -619,7 +619,7 @@ public static object CreateDefaultText(global::Microsoft.Maui.Controls.BindableO
 			        return defaultValue;
 			    }
 
-			    public static bool IsInitializingCustomDuration = false;
+			    public static volatile bool IsInitializingCustomDuration = false;
 			    public static object CreateDefaultCustomDuration(global::Microsoft.Maui.Controls.BindableObject bindable)
 			    {
 			        IsInitializingCustomDuration = true;
@@ -632,4 +632,45 @@ public static object CreateDefaultCustomDuration(global::Microsoft.Maui.Controls
 
 		await VerifySourceGeneratorAsync(source, expectedGenerated);
 	}
+
+	[Fact]
+	public async Task GenerateBindableProperty_GenericClassExample_GeneratesCorrectCode()
+	{
+		const string source =
+			/* language=C#-test */
+			//lang=csharp
+			$$"""
+			using CommunityToolkit.Maui;
+			using Microsoft.Maui.Controls;
+
+			namespace {{defaultTestNamespace}};
+
+			public partial class {{defaultTestClassName}}<T> : View
+			{
+			    [BindablePropertyAttribute]
+			    public partial string Text { get; set; }
+			}
+			""";
+
+		const string expectedGenerated =
+			/* language=C#-test */
+			//lang=csharp
+			$$"""
+			// <auto-generated>
+			// See: CommunityToolkit.Maui.SourceGenerators.Internal.BindablePropertyAttributeSourceGenerator
+			#pragma warning disable
+			#nullable enable
+			namespace {{defaultTestNamespace}};
+			public partial class {{defaultTestClassName}}<T>
+			{
+			    /// <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}}<T>), null, Microsoft.Maui.Controls.BindingMode.OneWay, null, null, null, null, null);
+			    public partial string Text { get => (string)GetValue(TextProperty); set => SetValue(TextProperty, value); }
+			}
+			""";
+
+		await VerifySourceGeneratorAsync(source, expectedGenerated);
+	}
 }

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

@@ -100,7 +100,7 @@ public partial class {{defaultTestClassName}}
 
             file static class __{{defaultTestClassName}}BindablePropertyInitHelpers
             {
-                public static bool IsInitializingInvoiceStatus = false;
+                public static volatile bool IsInitializingInvoiceStatus = false;
                 public static object CreateDefaultInvoiceStatus(global::Microsoft.Maui.Controls.BindableObject bindable)
                 {
                     IsInitializingInvoiceStatus = true;
@@ -160,7 +160,7 @@ public partial class {{defaultTestClassName}}
 
             file static class __{{defaultTestClassName}}BindablePropertyInitHelpers
             {
-                public static bool IsInitializingInvoiceStatus = false;
+                public static volatile bool IsInitializingInvoiceStatus = false;
                 public static object CreateDefaultInvoiceStatus(global::Microsoft.Maui.Controls.BindableObject bindable)
                 {
                     IsInitializingInvoiceStatus = true;
@@ -516,7 +516,7 @@ public partial class {{defaultTestClassName}}
 
             file static class __{{defaultTestClassName}}BindablePropertyInitHelpers
             {
-                public static bool IsInitializingIsEnabled = false;
+                public static volatile bool IsInitializingIsEnabled = false;
                 public static object CreateDefaultIsEnabled(global::Microsoft.Maui.Controls.BindableObject bindable)
                 {
                     IsInitializingIsEnabled = true;
@@ -525,7 +525,7 @@ public static object CreateDefaultIsEnabled(global::Microsoft.Maui.Controls.Bind
                     return defaultValue;
                 }
 
-                public static bool IsInitializingPi = false;
+                public static volatile bool IsInitializingPi = false;
                 public static object CreateDefaultPi(global::Microsoft.Maui.Controls.BindableObject bindable)
                 {
                     IsInitializingPi = true;
@@ -534,7 +534,7 @@ public static object CreateDefaultPi(global::Microsoft.Maui.Controls.BindableObj
                     return defaultValue;
                 }
 
-                public static bool IsInitializingLetter = false;
+                public static volatile bool IsInitializingLetter = false;
                 public static object CreateDefaultLetter(global::Microsoft.Maui.Controls.BindableObject bindable)
                 {
                     IsInitializingLetter = true;
@@ -543,7 +543,7 @@ public static object CreateDefaultLetter(global::Microsoft.Maui.Controls.Bindabl
                     return defaultValue;
                 }
 
-                public static bool IsInitializingTimeSpent = false;
+                public static volatile bool IsInitializingTimeSpent = false;
                 public static object CreateDefaultTimeSpent(global::Microsoft.Maui.Controls.BindableObject bindable)
                 {
                     IsInitializingTimeSpent = true;
@@ -552,7 +552,7 @@ public static object CreateDefaultTimeSpent(global::Microsoft.Maui.Controls.Bind
                     return defaultValue;
                 }
 
-                public static bool IsInitializingDoubleEpsilon = false;
+                public static volatile bool IsInitializingDoubleEpsilon = false;
                 public static object CreateDefaultDoubleEpsilon(global::Microsoft.Maui.Controls.BindableObject bindable)
                 {
                     IsInitializingDoubleEpsilon = true;
@@ -561,7 +561,7 @@ public static object CreateDefaultDoubleEpsilon(global::Microsoft.Maui.Controls.
                     return defaultValue;
                 }
 
-                public static bool IsInitializingSingleEpsilon = false;
+                public static volatile bool IsInitializingSingleEpsilon = false;
                 public static object CreateDefaultSingleEpsilon(global::Microsoft.Maui.Controls.BindableObject bindable)
                 {
                     IsInitializingSingleEpsilon = true;
@@ -570,7 +570,7 @@ public static object CreateDefaultSingleEpsilon(global::Microsoft.Maui.Controls.
                     return defaultValue;
                 }
 
-                public static bool IsInitializingCurrentTime = false;
+                public static volatile bool IsInitializingCurrentTime = false;
                 public static object CreateDefaultCurrentTime(global::Microsoft.Maui.Controls.BindableObject bindable)
                 {
                     IsInitializingCurrentTime = true;

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

@@ -134,6 +134,60 @@ public partial class {{defaultTestClassName}}<T, U>
 		await VerifySourceGeneratorAsync(source, expectedGenerated);
 	}
 
+	[Fact]
+	public async Task GenerateBindableProperty_GenericClass_WithInitializer_GeneratesCorrectCode()
+	{
+		const string source =
+			/* language=C#-test */
+			//lang=csharp
+			$$"""
+		using CommunityToolkit.Maui;
+		using Microsoft.Maui.Controls;
+
+		namespace {{defaultTestNamespace}};
+
+		public partial class {{defaultTestClassName}}<T,U> : View where T : class
+		{
+		    [BindableProperty]
+		    public partial T? Value { get; set; } = default;
+		}
+		""";
+
+		const string expectedGenerated =
+			/* language=C#-test */
+			//lang=csharp
+			$$"""
+		// <auto-generated>
+		// See: CommunityToolkit.Maui.SourceGenerators.Internal.BindablePropertyAttributeSourceGenerator
+		#pragma warning disable
+		#nullable enable
+		namespace {{defaultTestNamespace}};
+		public partial class {{defaultTestClassName}}<T, U>
+		{
+		    /// <summary>
+		    /// Backing BindableProperty for the <see cref = "Value"/> property.
+		    /// </summary>
+		    public static readonly global::Microsoft.Maui.Controls.BindableProperty ValueProperty = global::Microsoft.Maui.Controls.BindableProperty.Create("Value", typeof(T), typeof({{defaultTestNamespace}}.{{defaultTestClassName}}<T, U>), null, Microsoft.Maui.Controls.BindingMode.OneWay, null, null, null, null, __{{defaultTestClassName}}BindablePropertyInitHelpers.CreateDefaultValue);
+		    public partial T? Value { get => __{{defaultTestClassName}}BindablePropertyInitHelpers.IsInitializingValue ? field : (T? )GetValue(ValueProperty); set => SetValue(ValueProperty, value); }
+
+		    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+		    private static class __{{defaultTestClassName}}BindablePropertyInitHelpers
+		    {
+		        public static volatile bool IsInitializingValue = false;
+		        public static object CreateDefaultValue(global::Microsoft.Maui.Controls.BindableObject bindable)
+		        {
+		            IsInitializingValue = true;
+		            var defaultValue = (({{defaultTestClassName}}<T, U>)bindable).Value;
+		            IsInitializingValue = false;
+		            return defaultValue;
+		        }
+		    }
+		}
+		""";
+
+		await VerifySourceGeneratorAsync(source, expectedGenerated);
+	}
+
 	[Fact]
 	public async Task GenerateBindableProperty_NestedClass_GeneratesCorrectCode()
 	{

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

@@ -182,17 +182,17 @@ static string GenerateSource(SemanticValues value)
 			? classNameWithGenerics
 			: string.Concat(value.ClassInformation.ContainingTypes, ".", classNameWithGenerics);
 
-		var fileStaticClassName = $"__{classNameWithGenerics}BindablePropertyInitHelpers";
+		var bindablePropertyInitHelpersClassName = $"__{value.ClassInformation.ClassName}BindablePropertyInitHelpers";
 
 		foreach (var info in value.BindableProperties)
 		{
 			if (info.IsReadOnlyBindableProperty)
 			{
-				GenerateReadOnlyBindableProperty(sb, in info, fileStaticClassName);
+				GenerateReadOnlyBindableProperty(sb, in info, bindablePropertyInitHelpersClassName);
 			}
 			else
 			{
-				GenerateBindableProperty(sb, in info, fileStaticClassName);
+				GenerateBindableProperty(sb, in info, bindablePropertyInitHelpersClassName);
 			}
 
 			if (info.ShouldUsePropertyInitializer)
@@ -209,7 +209,20 @@ static string GenerateSource(SemanticValues value)
 				}
 			}
 
-			GenerateProperty(sb, in info, fileStaticClassName);
+			GenerateProperty(sb, in info, bindablePropertyInitHelpersClassName);
+		}
+
+		// If we generated any helper members and the declaring class is generic,
+		// emit the helper class nested inside the generated partial class so
+		// generic type parameters are in scope for casts used by the helper.
+		if (fileStaticClassStringBuilder.Length > 0 && !string.IsNullOrEmpty(value.ClassInformation.GenericTypeParameters))
+		{
+			sb.Append("[global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]");
+			sb.Append("\n");
+			sb.Append("private static class ").Append(bindablePropertyInitHelpersClassName).Append("\n{");
+			sb.Append("\n");
+			sb.Append(fileStaticClassStringBuilder.ToString());
+			sb.Append("}\n\n");
 		}
 
 		sb.Append('}');
@@ -224,10 +237,12 @@ static string GenerateSource(SemanticValues value)
 			}
 		}
 
-		// If we generated any helper members, emit a file static class with them.
-		if (fileStaticClassStringBuilder.Length > 0)
+		// If we generated any helper members and the declaring class is not generic,
+		// emit a file static class with them. Generic types have their helpers emitted
+		// nested inside the class above to ensure type parameter scope.
+		if (fileStaticClassStringBuilder.Length > 0 && string.IsNullOrEmpty(value.ClassInformation.GenericTypeParameters))
 		{
-			sb.Append("\n\nfile static class ").Append(fileStaticClassName).Append("\n{\n");
+			sb.Append("\n\nfile static class ").Append(bindablePropertyInitHelpersClassName).Append("\n{\n");
 			sb.Append(fileStaticClassStringBuilder.ToString());
 			sb.Append("}\n");
 		}
@@ -598,7 +613,7 @@ static string GetFormattedReturnType(ITypeSymbol typeSymbol)
 	static void AppendHelperInitializingField(StringBuilder fileStaticClassStringBuilder, in BindablePropertyModel info)
 	{
 		// Make the flag public static so it can be referenced from the generated partial class in the same file.
-		fileStaticClassStringBuilder.Append("public static bool ")
+		fileStaticClassStringBuilder.Append("public static volatile bool ")
 			.Append(info.InitializingPropertyName)
 			.Append(" = false;\n");
 	}

src/CommunityToolkit.Maui.UnitTests/Animations/BaseAnimationTests.cs

@@ -0,0 +1,38 @@
+using CommunityToolkit.Maui.Animations;
+using CommunityToolkit.Maui.Core;
+using Xunit;
+
+namespace CommunityToolkit.Maui.UnitTests.Animations;
+
+public class BaseAnimationTests
+{
+	[Fact]
+	public void BaseAnimationT_EnsureDefaults()
+	{
+		// Arrange
+		BaseAnimation animation = new MockBaseAnimation();
+
+		// Act // Assert
+		Assert.Equal(BaseAnimationDefaults.Easing, animation.Easing);
+		Assert.Equal(BaseAnimationDefaults.Length, animation.Length);
+	}
+
+	[Fact]
+	public void BaseAnimation_EnsureDefaults()
+	{
+		// Arrange
+		BaseAnimation<VisualElement> animation = new MockBaseAnimation();
+
+		// Act // Assert
+		Assert.Equal(BaseAnimationDefaults.Easing, animation.Easing);
+		Assert.Equal(BaseAnimationDefaults.Length, animation.Length);
+	}
+
+	class MockBaseAnimation : BaseAnimation
+	{
+		public override Task Animate(VisualElement view, CancellationToken token = default)
+		{
+			throw new NotImplementedException();
+		}
+	}
+}

src/CommunityToolkit.Maui.UnitTests/Animations/FadeAnimationTests.cs

@@ -1,4 +1,5 @@
 using CommunityToolkit.Maui.Animations;
+using CommunityToolkit.Maui.Core;
 using CommunityToolkit.Maui.UnitTests.Mocks;
 using FluentAssertions;
 using Xunit;
@@ -67,4 +68,16 @@ public async Task AnimateShouldReturnToOriginalOpacity()
 
 		label.Opacity.Should().Be(0.9);
 	}
+
+	[Fact]
+	public void EnsureDefaults()
+	{
+		// Arrange
+		var animation = new FadeAnimation();
+
+		// Act // Assert
+		Assert.Equal(BaseAnimationDefaults.Easing, animation.Easing);
+		Assert.Equal(FadeAnimationDefaults.Length, animation.Length);
+		Assert.Equal(FadeAnimationDefaults.Opacity, animation.Opacity);
+	}
 }