Merge pull request #6613 from Youssef1313/issues/2937

Generate native ctor only when a ctor with required signature exists in base types

Author: jeromelaban

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

@@ -5,6 +5,7 @@
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Uno.UI.SourceGenerators.Helpers;
+using System.Diagnostics;
 
 #if NETFRAMEWORK
 using Uno.SourceGeneration;
@@ -40,7 +41,7 @@ private class SerializationMethodsGenerator : SymbolVisitor
 			private readonly INamedTypeSymbol? _intPtrSymbol;
 			private readonly INamedTypeSymbol? _jniHandleOwnershipSymbol;
 			private readonly INamedTypeSymbol?[]? _javaCtorParams;
-			private readonly INamedTypeSymbol? _panelSymbol;
+
 			private const string BaseClassFormat =
 @"// <auto-generated>
 // *************************************************************
@@ -99,7 +100,6 @@ public SerializationMethodsGenerator(GeneratorExecutionContext context)
 				_androidViewSymbol = context.Compilation.GetTypeByMetadataName("Android.Views.View");
 				_intPtrSymbol = context.Compilation.GetTypeByMetadataName("System.IntPtr");
 				_jniHandleOwnershipSymbol = context.Compilation.GetTypeByMetadataName("Android.Runtime.JniHandleOwnership");
-				_panelSymbol = context.Compilation.GetTypeByMetadataName("Windows.UI.Xaml.Controls.Panel");
 				_javaCtorParams = new[] { _intPtrSymbol, _jniHandleOwnershipSymbol };
 			}
 
@@ -140,12 +140,10 @@ private void ProcessType(INamedTypeSymbol typeSymbol)
 
 				if (isiOSView || ismacOSView)
 				{
-					var nativeCtor = typeSymbol
-						.GetMethods()
-						.Where(m => m.MethodKind == MethodKind.Constructor && SymbolEqualityComparer.Default.Equals(m.Parameters.FirstOrDefault()?.Type, _intPtrSymbol))
-						.FirstOrDefault();
+					Func<IMethodSymbol, bool> predicate = m => !m.Parameters.IsDefaultOrEmpty && SymbolEqualityComparer.Default.Equals(m.Parameters[0].Type, _intPtrSymbol);
+					var nativeCtor = GetNativeCtor(typeSymbol, predicate, considerAllBaseTypes: false);
 
-					if (nativeCtor == null)
+					if (nativeCtor == null && GetNativeCtor(typeSymbol.BaseType, predicate, considerAllBaseTypes: true) != null)
 					{
 						_context.AddSource(
 							HashBuilder.BuildIDFromSymbol(typeSymbol),
@@ -162,15 +160,10 @@ private void ProcessType(INamedTypeSymbol typeSymbol)
 
 				if (isAndroidView)
 				{
+					Func<IMethodSymbol, bool> predicate = m => m.Parameters.Select(p => p.Type).SequenceEqual(_javaCtorParams ?? Array.Empty<ITypeSymbol?>());
+					var nativeCtor = GetNativeCtor(typeSymbol, predicate, considerAllBaseTypes: false);
 
-					var nativeCtor = typeSymbol
-						.GetMethods()
-						.Where(m =>
-							m.MethodKind == MethodKind.Constructor
-							&& m.Parameters.Select(p => p.Type).SequenceEqual(_javaCtorParams ?? Array.Empty<ITypeSymbol?>()))
-						.FirstOrDefault();
-
-					if (nativeCtor == null)
+					if (nativeCtor == null && GetNativeCtor(typeSymbol.BaseType, predicate, considerAllBaseTypes: true) != null)
 					{
 						_context.AddSource(
 							HashBuilder.BuildIDFromSymbol(typeSymbol),
@@ -184,6 +177,32 @@ private void ProcessType(INamedTypeSymbol typeSymbol)
 						);
 					}
 				}
+
+				static IMethodSymbol? GetNativeCtor(INamedTypeSymbol? type, Func<IMethodSymbol, bool> predicate, bool considerAllBaseTypes)
+				{
+					// Consider:
+					// Type A -> Type B -> Type C
+					// HasCtor   NoCtor    NoCtor
+					// We want to generate the ctor for both Type B and Type C
+					// But since the generator doesn't guarantee Type B is getting processed first,
+					// We need to check the inheritance hierarchy.
+					// However, assume Type B wasn't declared in source, we can't generate the ctor for it.
+					// Consequently, Type C shouldn't generate source as well.
+					if (type is null)
+					{
+						return null;
+					}
+
+					var ctor = type.GetMembers(WellKnownMemberNames.InstanceConstructorName).Cast<IMethodSymbol>().FirstOrDefault(predicate);
+					if (ctor != null || !considerAllBaseTypes || !type.Locations.Any(l => l.IsInSource))
+					{
+						return ctor;
+					}
+					else
+					{
+						return GetNativeCtor(type.BaseType, predicate, true);
+					}
+				}
 			}
 
 			private bool NeedsExplicitDefaultCtor(INamedTypeSymbol typeSymbol)

src/Uno.UI.RuntimeTests/Tests/NativeCtorGeneratorTests/GameBoardCanvas.cs

@@ -0,0 +1,25 @@
+#if __ANDROID__
+using Android.Content;
+
+namespace Uno.UI.RuntimeTests.Tests.NativeCtorGeneratorTests
+{
+	public partial class MyCustomView : Android.Views.View
+	{
+		public MyCustomView(Context context) : base(context) { }
+		public MyCustomView(Context context, Android.Util.IAttributeSet attributeSet) : base(context, attributeSet) { }
+	}
+
+	public partial class GameBoardCanvas : MyCustomView
+	{
+		public GameBoardCanvas(Context context)
+			: base(context)
+		{
+		}
+
+		public GameBoardCanvas(Context context, Android.Util.IAttributeSet attributeSet)
+			: base(context, attributeSet)
+		{
+		}
+	}
+}
+#endif