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

[jeffkwoh]

Adds supports for a flag to add a javax.annotation.Generated annotation in the Kotlin generated code

Fixes flutter/flutter#181234

[gemini-code-assist]

Code Review

This pull request introduces a feature to add a javax.annotation.Generated annotation to the generated Kotlin code, controlled by a new useGeneratedAnnotation flag. The implementation correctly adds the flag to the options, parses it from command-line arguments, and conditionally adds the annotation in the Kotlin generator. The changes are accompanied by corresponding tests. My review includes suggestions to improve code maintainability by refactoring a magic string into a constant and reducing code duplication in the newly added tests.

[jeffkwoh]

Having difficulties executing

patch -p1 <<DONE
diff --git a/packages/pigeon/lib/src/pigeon_lib.dart b/packages/pigeon/lib/src/pigeon_lib.dart
index 7495903b9..e638629f3 100644
--- a/packages/pigeon/lib/src/pigeon_lib.dart
+++ b/packages/pigeon/lib/src/pigeon_lib.dart
@@ -547,8 +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.')
+    ..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).',
@@ -640,7 +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,
+        useGeneratedAnnotation:
+            results['kotlin_use_generated_annotation'] as bool? ?? false,
       ),
       cppHeaderOut: results['cpp_header_out'] as String?,
       cppSourceOut: results['cpp_source_out'] as String?,
diff --git a/packages/pigeon/test/pigeon_lib_test.dart b/packages/pigeon/test/pigeon_lib_test.dart
index 4748c9caf..86b049855 100644
--- a/packages/pigeon/test/pigeon_lib_test.dart
+++ b/packages/pigeon/test/pigeon_lib_test.dart
@@ -136,7 +136,7 @@ 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',
@@ -144,7 +144,6 @@ void main() {
     expect(opts.kotlinOptions!.useGeneratedAnnotation, isTrue);
   });
 
-
   test('parse args - cpp_header_out', () {
     final PigeonOptions opts = Pigeon.parseArgs(<String>[
       '--cpp_header_out',

DONE

will set up dart env locally and reformat or manually make changes

[tarrinneal]

will set up dart env locally and reformat or manually make changes

There will be hundreds of changes if you can't run the formatter. I would highly recommend not doing it manually.

Or I can format your code and push it up. If that's easier for you.

[jeffkwoh]

Managed to install dart! PTAL! (I don't know how to trigger AI review again)

[tarrinneal]

This all looks good. The "magic strings" comment from the ai is pretty funny when you look at the rest of the generator files, but there will be some upcoming changes in that regard soon anyway, so might as well start here :)

I do think it would be a good idea to add the annotations to at least one of the generated test files, should be as simple as adding a parameter to the 'runPigeon' method in the 'generation.dart' file in the tool/shared directory. Then adding an argument to the call to that method in generateTestPigeons in the same file for one file.

[tarrinneal]

Sorry I forgot to approve last time

[auto-submit]

autosubmit label was removed for flutter/packages/10961, because This PR has not met approval requirements for merging. The PR author is not a member of flutter-hackers and needs 1 more review(s) in order to merge this PR.

• Merge guidelines: A PR needs at least one approved review if the author is already part of flutter-hackers or two member reviews if the author is not a flutter-hacker before re-applying the autosubmit label. Reviewers: If you left a comment approving, please use the "approve" review action instead.

[stuartmorgan-g]

The code looks good, but since this is new API it needs to be a minor version bump since we use semver.

[stuartmorgan-g]

LGTM