fix(hr): Fix RegisterAttribute generation for nested/generic types

src/SourceGenerators/SourceGeneratorHelpers/Helpers/SymbolExtensions.cs

@@ -8,6 +8,7 @@
 using Uno;
 using Uno.Roslyn;
 using Microsoft.CodeAnalysis.PooledObjects;
+using System.Diagnostics;
 
 namespace Microsoft.CodeAnalysis
 {
@@ -398,7 +399,10 @@ ITypeSymbol ts when ts.ContainingType is ISymbol pt
 			return type?.GetFullyQualifiedTypeExcludingGlobal();
 		}
 
-		public static string GetFullMetadataName(this ITypeSymbol symbol)
+		// forRegisterAttributeDotReplacement is used specifically by NativeCtorsGenerator to generate for the Android/iOS RegisterAttribute
+		// A non-null value means we are generating for RegisterAttribute, and we replace invalid characters with '_'.
+		// The '.' is special cased to be replaced by the value of forRegisterAttributeDotReplacement, whether it's '_' or '/'
+		public static string GetFullMetadataName(this ITypeSymbol symbol, char? forRegisterAttributeDotReplacement = null)
 		{
 			ISymbol s = symbol;
 			var sb = new StringBuilder(s.MetadataName);
@@ -428,9 +432,19 @@ public static string GetFullMetadataName(this ITypeSymbol symbol)
 
 			var namedType = symbol as INamedTypeSymbol;
 
-			if (namedType?.TypeArguments.Any() ?? false)
+			// When generating for RegisterAttribute, the name we pass to the attribute is used by Xamarin tooling for generating Java files, specifically, it's used for the class name.
+			// The characters '.', '+', and '`' are not valid characters for a class name.
+			// On Android, we use '/' as replacement for '.' to match Jni name:
+			// https://github.com/xamarin/java.interop/blob/38c8a827e78ffe9c80ad2313a9e0e0d4f8215184/src/Java.Interop.Tools.TypeNameMappings/Java.Interop.Tools.TypeNameMappings/JavaNativeTypeManager.cs#L693-L699
+			if (forRegisterAttributeDotReplacement.HasValue)
 			{
-				var genericArgs = namedType.TypeArguments.Select(GetFullMetadataName).JoinBy(",");
+				var replacement = forRegisterAttributeDotReplacement.Value;
+				sb.Replace('.', replacement).Replace('+', '_').Replace('`', '_');
+			}
+			else if (namedType?.TypeArguments.Any() ?? false)
+			{
+				// We don't append type arguments when generating for RegisterAttribute because '[' and ']' are invalid characters for a class name.
+				var genericArgs = namedType.TypeArguments.Select(a => GetFullMetadataName(a, null)).JoinBy(",");
 				sb.Append($"[{genericArgs}]");
 			}
 

src/SourceGenerators/Uno.UI.SourceGenerators/NativeCtor/NativeCtorsGenerator.cs

@@ -5,7 +5,6 @@
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Uno.UI.SourceGenerators.Helpers;
-using System.Diagnostics;
 using Uno.Extensions;
 using Uno.Roslyn;
 
@@ -37,7 +36,7 @@ private class SerializationMethodsGenerator : SymbolVisitor
 			private readonly INamedTypeSymbol? _androidViewSymbol;
 			private readonly INamedTypeSymbol? _intPtrSymbol;
 			private readonly INamedTypeSymbol? _jniHandleOwnershipSymbol;
-			private readonly INamedTypeSymbol?[]? _javaCtorParams;
+			private readonly INamedTypeSymbol?[] _javaCtorParams;
 			private readonly string _configuration;
 			private readonly bool _isDebug;
 			private readonly bool _isHotReloadEnabled;
@@ -129,7 +128,7 @@ private void ProcessType(INamedTypeSymbol typeSymbol)
 
 				if (isAndroidView)
 				{
-					Func<IMethodSymbol, bool> predicate = m => m.Parameters.Select(p => p.Type).SequenceEqual(_javaCtorParams ?? Array.Empty<ITypeSymbol?>());
+					Func<IMethodSymbol, bool> predicate = m => m.Parameters.Select(p => p.Type).SequenceEqual(_javaCtorParams);
 					var nativeCtor = GetNativeCtor(typeSymbol, predicate, considerAllBaseTypes: false);
 
 					if (nativeCtor == null && GetNativeCtor(typeSymbol.BaseType, predicate, considerAllBaseTypes: true) != null)
@@ -164,7 +163,7 @@ string GetGeneratedCode(INamedTypeSymbol typeSymbol)
 						// generated at runtime
 
 						var registerParamApple = _isHotReloadEnabled
-							? $"\"{typeSymbol.GetFullMetadataName().Replace(".", "_")}\""
+							? $"\"{typeSymbol.GetFullMetadataName(forRegisterAttributeDotReplacement: '_')}\""
 							: "";
 
 						builder.AppendLineIndented($"[global::Foundation.Register({registerParamApple})]");
@@ -175,7 +174,7 @@ string GetGeneratedCode(INamedTypeSymbol typeSymbol)
 						{
 							builder.AppendLineIndented("#if __ANDROID__");
 
-							var registerParamAndroid = $"\"{typeSymbol.GetFullMetadataName().Replace(".", "/")}\"";
+							var registerParamAndroid = $"\"{typeSymbol.GetFullMetadataName(forRegisterAttributeDotReplacement: '/')}\"";
 
 							builder.AppendLineIndented($"[global::Android.Runtime.Register({registerParamAndroid})]");
 

src/Uno.UI.RuntimeTests/Tests/NativeCtorGeneratorTests/NestedGenericClasses.Android.cs

@@ -0,0 +1,28 @@
+using Android.Content;
+
+namespace Uno.UI.RuntimeTests.Tests.NativeCtorGeneratorTests
+{
+	public partial class GenericClass<T1, T2> : Android.Views.View
+	{
+		public GenericClass(Context context) : base(context) { }
+		public GenericClass(Context context, Android.Util.IAttributeSet attributeSet) : base(context, attributeSet) { }
+
+		public partial class NestedGenericClass<T3> : Android.Views.View
+		{
+			public NestedGenericClass(Context context) : base(context) { }
+			public NestedGenericClass(Context context, Android.Util.IAttributeSet attributeSet) : base(context, attributeSet) { }
+		}
+	}
+}
+
+public partial class GenericClassGlobalNamespace<T1, T2> : Android.Views.View
+{
+	public GenericClassGlobalNamespace(Context context) : base(context) { }
+	public GenericClassGlobalNamespace(Context context, Android.Util.IAttributeSet attributeSet) : base(context, attributeSet) { }
+
+	public partial class NestedGenericClassGlobalNamespace<T3> : Android.Views.View
+	{
+		public NestedGenericClassGlobalNamespace(Context context) : base(context) { }
+		public NestedGenericClassGlobalNamespace(Context context, Android.Util.IAttributeSet attributeSet) : base(context, attributeSet) { }
+	}
+}