[pigeon] Support javax.annotation.Generated annotation in Kotlin generator

packages/pigeon/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 26.2.0
+
+* [kotlin] Adds option to add javax.annotation.Generated annotation.
+
 ## 26.1.10
 
 * Dramatically reduces the number of File write operations sent to the operating

packages/pigeon/lib/src/generator_tools.dart

@@ -15,7 +15,10 @@ import 'generator.dart';
 /// The current version of pigeon.
 ///
 /// This must match the version in pubspec.yaml.
-const String pigeonVersion = '26.1.10';
+const String pigeonVersion = '26.2.0';
+
+/// Default plugin package name.
+const String defaultPluginPackageName = 'dev.flutter.pigeon';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {

packages/pigeon/lib/src/java/java_generator.dart

@@ -202,7 +202,9 @@ class JavaGenerator extends StructuredGenerator<InternalJavaOptions> {
       '@SuppressWarnings({"unused", "unchecked", "CodeBlock2Expr", "RedundantSuppression", "serial"})',
     );
     if (generatorOptions.useGeneratedAnnotation ?? false) {
-      indent.writeln('@javax.annotation.Generated("dev.flutter.pigeon")');
+      indent.writeln(
+        '@javax.annotation.Generated("$defaultPluginPackageName")',
+      );
     }
     indent.writeln('public class ${generatorOptions.className!} {');
     indent.inc();

packages/pigeon/lib/src/kotlin/kotlin_generator.dart

@@ -35,6 +35,10 @@ const String _pigeonMethodChannelCodec = 'PigeonMethodCodec';
 
 const String _overflowClassName = '${classNamePrefix}CodecOverflow';
 
+/// Kotlin file-level annotation for generated code.
+const String kotlinGeneratedAnnotation =
+    '@file:Generated("$defaultPluginPackageName")';
+
 /// Options that control how Kotlin code will be generated.
 class KotlinOptions {
   /// Creates a [KotlinOptions] object
@@ -44,6 +48,7 @@ class KotlinOptions {
     this.errorClassName,
     this.includeErrorClass = true,
     this.fileSpecificClassNameComponent,
+    this.useGeneratedAnnotation = false,
   });
 
   /// The package where the generated class will live.
@@ -64,6 +69,11 @@ class KotlinOptions {
   /// A String to augment class names to avoid cross file collisions.
   final String? fileSpecificClassNameComponent;
 
+  /// Determines if the `javax.annotation.Generated` is used in the output. This
+  /// is false by default since that dependency isn't available in plugins by
+  /// default.
+  final bool useGeneratedAnnotation;
+
   /// Creates a [KotlinOptions] from a Map representation where:
   /// `x = KotlinOptions.fromMap(x.toMap())`.
   static KotlinOptions fromMap(Map<String, Object> map) {
@@ -74,6 +84,7 @@ class KotlinOptions {
       includeErrorClass: map['includeErrorClass'] as bool? ?? true,
       fileSpecificClassNameComponent:
           map['fileSpecificClassNameComponent'] as String?,
+      useGeneratedAnnotation: map['useGeneratedAnnotation'] as bool? ?? false,
     );
   }
 
@@ -87,6 +98,7 @@ class KotlinOptions {
       'includeErrorClass': includeErrorClass,
       if (fileSpecificClassNameComponent != null)
         'fileSpecificClassNameComponent': fileSpecificClassNameComponent!,
+      'useGeneratedAnnotation': useGeneratedAnnotation,
     };
     return result;
   }
@@ -108,6 +120,7 @@ class InternalKotlinOptions extends InternalOptions {
     this.errorClassName,
     this.includeErrorClass = true,
     this.fileSpecificClassNameComponent,
+    this.useGeneratedAnnotation = false,
   });
 
   /// Creates InternalKotlinOptions from KotlinOptions.
@@ -119,6 +132,7 @@ class InternalKotlinOptions extends InternalOptions {
        copyrightHeader = options.copyrightHeader ?? copyrightHeader,
        errorClassName = options.errorClassName,
        includeErrorClass = options.includeErrorClass,
+       useGeneratedAnnotation = options.useGeneratedAnnotation,
        fileSpecificClassNameComponent =
            options.fileSpecificClassNameComponent ??
            kotlinOut.split('/').lastOrNull?.split('.').first;
@@ -143,6 +157,11 @@ class InternalKotlinOptions extends InternalOptions {
 
   /// A String to augment class names to avoid cross file collisions.
   final String? fileSpecificClassNameComponent;
+
+  /// Determines if the `javax.annotation.Generated` is used in the output. This
+  /// is false by default since that dependency isn't available in plugins by
+  /// default.
+  final bool useGeneratedAnnotation;
 }
 
 /// Options that control how Kotlin code will be generated for a specific
@@ -192,6 +211,9 @@ class KotlinGenerator extends StructuredGenerator<InternalKotlinOptions> {
     indent.writeln('// ${getGeneratedCodeWarning()}');
     indent.writeln('// $seeAlsoWarning');
     indent.writeln('@file:Suppress("UNCHECKED_CAST", "ArrayInDataClass")');
+    if (generatorOptions.useGeneratedAnnotation) {
+      indent.writeln(kotlinGeneratedAnnotation);
+    }
   }
 
   @override
@@ -215,6 +237,9 @@ class KotlinGenerator extends StructuredGenerator<InternalKotlinOptions> {
     indent.writeln('import io.flutter.plugin.common.StandardMessageCodec');
     indent.writeln('import java.io.ByteArrayOutputStream');
     indent.writeln('import java.nio.ByteBuffer');
+    if (generatorOptions.useGeneratedAnnotation) {
+      indent.writeln('import javax.annotation.Generated');
+    }
   }
 
   @override

packages/pigeon/lib/src/pigeon_lib.dart

@@ -547,6 +547,10 @@ ${_argParser.usage}''';
       help: 'The package that generated Kotlin code will be in.',
       aliases: const <String>['experimental_kotlin_package'],
     )
+    ..addFlag(
+      'kotlin_use_generated_annotation',
+      help: 'Adds javax.annotation.Generated annotation to the output.',
+    )
     ..addOption(
       'cpp_header_out',
       help: 'Path to generated C++ header file (.h).',
@@ -638,6 +642,8 @@ ${_argParser.usage}''';
       kotlinOut: results['kotlin_out'] as String?,
       kotlinOptions: KotlinOptions(
         package: results['kotlin_package'] as String?,
+        useGeneratedAnnotation:
+            results['kotlin_use_generated_annotation'] as bool? ?? false,
       ),
       cppHeaderOut: results['cpp_header_out'] as String?,
       cppSourceOut: results['cpp_source_out'] as String?,

packages/pigeon/platform_tests/test_plugin/android/build.gradle

@@ -66,6 +66,7 @@ android {
     }
 
     dependencies {
+        compileOnly 'javax.annotation:javax.annotation-api:1.3.2'
         testImplementation("junit:junit:4.13.2")
         testImplementation("io.mockk:mockk:1.14.9")
         // org.jetbrains.kotlin:kotlin-bom artifact purpose is to align kotlin stdlib and related code versions.

packages/pigeon/pubspec.yaml

@@ -2,7 +2,7 @@ name: pigeon
 description: Code generator tool to make communication between Flutter and the host platform type-safe and easier.
 repository: https://github.com/flutter/packages/tree/main/packages/pigeon
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+pigeon%22
-version: 26.1.10 # This must match the version in lib/src/generator_tools.dart
+version: 26.2.0 # This must match the version in lib/src/generator_tools.dart
 
 environment:
   sdk: ^3.9.0

packages/pigeon/test/java_generator_test.dart

@@ -4,6 +4,7 @@
 
 import 'package:pigeon/pigeon.dart';
 import 'package:pigeon/src/ast.dart';
+import 'package:pigeon/src/generator_tools.dart';
 import 'package:pigeon/src/java/java_generator.dart';
 import 'package:test/test.dart';
 
@@ -1611,51 +1612,55 @@ void main() {
     );
   });
 
-  test('generated annotation', () {
-    final classDefinition = Class(name: 'Foobar', fields: <NamedType>[]);
-    final root = Root(
-      apis: <Api>[],
-      classes: <Class>[classDefinition],
-      enums: <Enum>[],
-    );
-    final sink = StringBuffer();
-    const javaOptions = InternalJavaOptions(
-      className: 'Messages',
-      useGeneratedAnnotation: true,
-      javaOut: '',
-    );
-    const generator = JavaGenerator();
-    generator.generate(
-      javaOptions,
-      root,
-      sink,
-      dartPackageName: DEFAULT_PACKAGE_NAME,
-    );
-    final code = sink.toString();
-    expect(code, contains('@javax.annotation.Generated("dev.flutter.pigeon")'));
-  });
+  group('generated annotation', () {
+    late Class classDefinition;
+    late Root root;
+    late StringBuffer sink;
+    late JavaGenerator generator;
+    const generatedAnnotation =
+        '@javax.annotation.Generated("$defaultPluginPackageName")';
 
-  test('no generated annotation', () {
-    final classDefinition = Class(name: 'Foobar', fields: <NamedType>[]);
-    final root = Root(
-      apis: <Api>[],
-      classes: <Class>[classDefinition],
-      enums: <Enum>[],
-    );
-    final sink = StringBuffer();
-    const javaOptions = InternalJavaOptions(className: 'Messages', javaOut: '');
-    const generator = JavaGenerator();
-    generator.generate(
-      javaOptions,
-      root,
-      sink,
-      dartPackageName: DEFAULT_PACKAGE_NAME,
-    );
-    final code = sink.toString();
-    expect(
-      code,
-      isNot(contains('@javax.annotation.Generated("dev.flutter.pigeon")')),
-    );
+    setUp(() {
+      classDefinition = Class(name: 'Foobar', fields: <NamedType>[]);
+      root = Root(
+        apis: <Api>[],
+        classes: <Class>[classDefinition],
+        enums: <Enum>[],
+      );
+      sink = StringBuffer();
+      generator = const JavaGenerator();
+    });
+
+    test('with generated annotation', () {
+      const javaOptions = InternalJavaOptions(
+        className: 'Messages',
+        useGeneratedAnnotation: true,
+        javaOut: '',
+      );
+      generator.generate(
+        javaOptions,
+        root,
+        sink,
+        dartPackageName: DEFAULT_PACKAGE_NAME,
+      );
+      final code = sink.toString();
+      expect(code, contains(generatedAnnotation));
+    });
+
+    test('without generated annotation', () {
+      const javaOptions = InternalJavaOptions(
+        className: 'Messages',
+        javaOut: '',
+      );
+      generator.generate(
+        javaOptions,
+        root,
+        sink,
+        dartPackageName: DEFAULT_PACKAGE_NAME,
+      );
+      final code = sink.toString();
+      expect(code, isNot(contains(generatedAnnotation)));
+    });
   });
 
   test('transfers documentation comments', () {

packages/pigeon/test/kotlin_generator_test.dart

@@ -982,6 +982,49 @@ void main() {
     expect(code, startsWith('// hello world'));
   });
 
+  group('generated annotation', () {
+    late Root root;
+    late KotlinGenerator generator;
+    late StringBuffer sink;
+
+    setUp(() {
+      root = Root(apis: <Api>[], classes: <Class>[], enums: <Enum>[]);
+      generator = const KotlinGenerator();
+      sink = StringBuffer();
+    });
+
+    test('with generated annotation', () {
+      final kotlinOptions = InternalKotlinOptions(
+        copyrightHeader: makeIterable('hello world'),
+        kotlinOut: '',
+        useGeneratedAnnotation: true,
+      );
+      generator.generate(
+        kotlinOptions,
+        root,
+        sink,
+        dartPackageName: DEFAULT_PACKAGE_NAME,
+      );
+      final code = sink.toString();
+      expect(code, contains(kotlinGeneratedAnnotation));
+    });
+
+    test('without generated annotation', () {
+      final kotlinOptions = InternalKotlinOptions(
+        copyrightHeader: makeIterable('hello world'),
+        kotlinOut: '',
+      );
+      generator.generate(
+        kotlinOptions,
+        root,
+        sink,
+        dartPackageName: DEFAULT_PACKAGE_NAME,
+      );
+      final code = sink.toString();
+      expect(code, isNot(contains(kotlinGeneratedAnnotation)));
+    });
+  });
+
   test('generics - list', () {
     final classDefinition = Class(
       name: 'Foobar',

packages/pigeon/test/pigeon_lib_test.dart

@@ -137,6 +137,13 @@ void main() {
     expect(opts.kotlinOptions?.package, equals('com.google.foo'));
   });
 
+  test('parse args - kotlin_use_generated_annotation', () {
+    final PigeonOptions opts = Pigeon.parseArgs(<String>[
+      '--kotlin_use_generated_annotation',
+    ]);
+    expect(opts.kotlinOptions!.useGeneratedAnnotation, isTrue);
+  });
+
   test('parse args - cpp_header_out', () {
     final PigeonOptions opts = Pigeon.parseArgs(<String>[
       '--cpp_header_out',

packages/pigeon/tool/shared/generation.dart

@@ -208,6 +208,21 @@ Future<int> generateTestPigeons({
       return generateCode;
     }
   }
+
+  // Test case for useGeneratedAnnotation feature with core_tests
+  final String corePascalCaseName = _snakeToPascalCase('core_tests');
+  final int generateCodeWithAnnotation = await runPigeon(
+    input: './pigeons/core_tests.dart',
+    kotlinOut:
+        '$outputBase/android/src/main/kotlin/com/example/test_plugin/annotation/${corePascalCaseName}WithAnnotation.gen.kt',
+    kotlinPackage: 'com.example.test_plugin.annotation',
+    kotlinErrorClassName: 'FlutterError',
+    kotlinUseGeneratedAnnotation: true,
+  );
+  if (generateCodeWithAnnotation != 0) {
+    return generateCodeWithAnnotation;
+  }
+
   return 0;
 }
 
@@ -217,6 +232,7 @@ Future<int> runPigeon({
   String? kotlinPackage,
   String? kotlinErrorClassName,
   bool kotlinIncludeErrorClass = true,
+  bool kotlinUseGeneratedAnnotation = false,
   bool swiftIncludeErrorClass = true,
   String? swiftOut,
   String? swiftErrorClassName,
@@ -291,6 +307,7 @@ Future<int> runPigeon({
         package: kotlinPackage,
         errorClassName: kotlinErrorClassName,
         includeErrorClass: kotlinIncludeErrorClass,
+        useGeneratedAnnotation: kotlinUseGeneratedAnnotation,
       ),
       objcHeaderOut: objcHeaderOut,
       objcSourceOut: objcSourceOut,