Fix Missing HandleAsync() Codefix When sealed

Author: viceroypenguin

src/Immediate.Handlers.CodeFixes/HandlerMethodMustExistCodeFixProvider.cs

@@ -48,53 +48,77 @@ private static Task<Document> AddHandleAsyncMethodAsync(Document document,
 			.OfType<RecordDeclarationSyntax>()
 			.FirstOrDefault(x =>
 				x.Identifier.Text.EndsWith("Query", StringComparison.Ordinal)
-				|| x.Identifier.Text.EndsWith("Command", StringComparison.Ordinal));
+				|| x.Identifier.Text.EndsWith("Command", StringComparison.Ordinal)
+			);
 
-		var methodDeclaration = MethodDeclaration(
+		var responseType = classDeclarationSyntax.Members
+			.OfType<RecordDeclarationSyntax>()
+			.FirstOrDefault(x => x.Identifier.Text.EndsWith("Response", StringComparison.Ordinal));
+
+		var methodDeclaration =
+			MethodDeclaration(
 				GenericName(
-						Identifier("ValueTask"))
+					Identifier("ValueTask")
+				)
 					.WithTypeArgumentList(
 						TypeArgumentList(
 							SingletonSeparatedList<TypeSyntax>(
-								PredefinedType(
-									Token(SyntaxKind.IntKeyword))))),
-				Identifier("HandleAsync"))
+								responseType is { }
+									? IdentifierName(responseType.Identifier.Text)
+									: PredefinedType(Token(SyntaxKind.IntKeyword))
+							)
+						)
+					),
+				Identifier("HandleAsync")
+			)
 			.WithModifiers(
 				TokenList(
-				[
-					Token(SyntaxKind.PrivateKeyword),
-					Token(SyntaxKind.StaticKeyword),
-				]))
+					classDeclarationSyntax.Modifiers.Any(m => m.IsKind(SyntaxKind.StaticKeyword))
+						? [Token(SyntaxKind.PrivateKeyword), Token(SyntaxKind.StaticKeyword)]
+						: [Token(SyntaxKind.PrivateKeyword)]
+				)
+			)
 			.WithParameterList(
 				ParameterList(
 					SeparatedList<ParameterSyntax>(
 						new SyntaxNodeOrToken[]
 						{
-							Parameter(
-									Identifier(
-										TriviaList(),
-										SyntaxKind.UnderscoreToken,
-										"_",
-										"_",
-										TriviaList()))
+							Parameter(Identifier(requestType?.Identifier.Text.ToCamelCase() ?? "_"))
 								.WithType(
-									IdentifierName(requestType?.Identifier.Text ?? "object")),
+									requestType is { }
+										? IdentifierName(requestType.Identifier.Text)
+										: PredefinedType(Token(SyntaxKind.ObjectKeyword))
+								),
+
 							Token(SyntaxKind.CommaToken),
-							Parameter(
-									Identifier("token"))
+
+							Parameter(Identifier("token"))
 								.WithType(
-									IdentifierName("CancellationToken")),
-						})))
+									IdentifierName("CancellationToken")
+								),
+						}
+					)
+				)
+			)
 			.WithBody(
 				Block(
 					SingletonList<StatementSyntax>(
 						ReturnStatement(
-							LiteralExpression(
-								SyntaxKind.DefaultLiteralExpression)))))
+							LiteralExpression(SyntaxKind.DefaultLiteralExpression)
+						)
+					)
+				)
+			)
 			.WithAdditionalAnnotations(Formatter.Annotation);
 
 		var newClassDecl = classDeclarationSyntax.AddMembers(methodDeclaration);
 
 		return Task.FromResult(document.WithSyntaxRoot(root.ReplaceNode(classDeclarationSyntax, newClassDecl)));
 	}
 }
+
+file static class Extensions
+{
+	public static string ToCamelCase(this string s) =>
+		char.ToLowerInvariant(s[0]) + s[1..];
+}

tests/Immediate.Handlers.Tests/AnalyzerTests/HandlerClassAnalyzerTests/Tests.HandleMethodIsCorrectWithIntReturn.cs

@@ -24,7 +24,7 @@ public static partial class {|IHR0019:GetUsersQuery|}
 			{
 				public record Query;
 
-				private static ValueTask<int> {|IHR0019:HandleAsync|}(
+				private static ValueTask<int> HandleAsync(
 					Query _,
 					CancellationToken token)
 				{

tests/Immediate.Handlers.Tests/CodeFixTests/HandlerMethodMustExistCodeFixProviderTests.cs

@@ -8,7 +8,7 @@ namespace Immediate.Handlers.Tests.CodeFixTests;
 public sealed partial class HandlerMethodMustExistCodeFixProviderTests
 {
 	[Fact]
-	public async Task HandleMethodDoesNotExist() =>
+	public async Task HandleMethodDoesNotExistOnStaticClass() =>
 		await CodeFixTestHelper.CreateCodeFixTest<HandlerClassAnalyzer, HandlerMethodMustExistCodeFixProvider>(
 			"""
 			using System;
@@ -41,7 +41,50 @@ public static class {|IHR0019:GetUsersQuery|}
 			{
 				public record Query;
 
-				private static ValueTask<int> {|IHR0019:HandleAsync|}(Query _, CancellationToken token)
+				private static ValueTask<int> HandleAsync(Query query, CancellationToken token)
+				{
+					return default;
+				}
+			}
+			""",
+			DriverReferenceAssemblies.Normal
+		).RunAsync(TestContext.Current.CancellationToken);
+
+	[Fact]
+	public async Task HandleMethodDoesNotExistOnSealedClass() =>
+		await CodeFixTestHelper.CreateCodeFixTest<HandlerClassAnalyzer, HandlerMethodMustExistCodeFixProvider>(
+			"""
+			using System;
+			using System.Collections.Generic;
+			using System.IO;
+			using System.Linq;
+			using System.Net.Http;
+			using System.Threading;
+			using System.Threading.Tasks;
+			using Immediate.Handlers.Shared;
+
+			[Handler]
+			public sealed class {|IHR0001:GetUsersQuery|}
+			{
+				public record Response;
+			}
+			""",
+			"""
+			using System;
+			using System.Collections.Generic;
+			using System.IO;
+			using System.Linq;
+			using System.Net.Http;
+			using System.Threading;
+			using System.Threading.Tasks;
+			using Immediate.Handlers.Shared;
+
+			[Handler]
+			public sealed class GetUsersQuery
+			{
+				public record Response;
+
+				private ValueTask<Response> HandleAsync(object _, CancellationToken token)
 				{
 					return default;
 				}