[pigeon] isEnum, isClass, fix swift casting, default values, optional method arguments, named method arguments (flutter#5355)

* **Breaking change** [dart] Renames locally defined host API variables.
  * Host api static field `codec` changed to `pigeonChannelCodec`.
* Adds named parameters to host API methods.
* Adds optional parameters to host API methods.
* Adds default values for class constructors and host API methods.
* Adds `isEnum` and `isClass` to `TypeDeclaration`s.
* Removes all `klass` variable names.

fixes flutter#127719
fixes flutter#98448
fixes flutter#80048

Author: tarrinneal

packages/pigeon/CHANGELOG.md

@@ -1,6 +1,16 @@
+## 14.0.0
+
+* **Breaking change** [dart] Renames locally defined host API variables.
+  * [dart] Host api static field `codec` changed to `pigeonChannelCodec`.
+* [dart] Adds named parameters to host API methods.
+* [dart] Adds optional parameters to host API methods.
+* [dart] Adds default values for class constructors and host API methods.
+* Adds `isEnum` and `isClass` to `TypeDeclaration`s.
+* [cpp] Fixes `FlutterError` generation being tied to ErrorOr.
+
 ## 13.1.2
 
-* Adds compatibilty with `analyzer` 6.x.
+* Adds compatibility with `analyzer` 6.x.
 
 ## 13.1.1
 
@@ -159,7 +169,7 @@
 * [java] Adds a `GeneratedApi.FlutterError` exception for passing custom error details (code, message, details).
 * [kotlin] Adds a `FlutterError` exception for passing custom error details (code, message, details).
 * [kotlin] Adds an `errorClassName` option in `KotlinOptions` for custom error class names.
-* [java] Removes legacy try catch from async apis.
+* [java] Removes legacy try catch from async APIs.
 * [java] Removes legacy null check on non-nullable method arguments.
 * [cpp] Fixes wrong order of items in `FlutterError`.
 * Adds `FlutterError` handling integration tests for all platforms.
@@ -212,7 +222,7 @@
 
 ## 7.2.1
 
-* [kotlin] Fixes Flutter api int errors with updated casting.
+* [kotlin] Fixes Flutter API int errors with updated casting.
 
 ## 7.2.0
 
@@ -238,7 +248,7 @@
 
 ## 7.1.2
 
-* [swift] Adds error handling to sync host api methods.
+* [swift] Adds error handling to sync host API methods.
 
 ## 7.1.1
 
@@ -352,7 +362,7 @@
 
 ## 4.2.4
 
-* [kotlin] Fixes Kotlin generated sync host api error.
+* [kotlin] Fixes Kotlin generated sync host API error.
 
 ## 4.2.3
 
@@ -831,7 +841,7 @@ class Foo {
 
 ## 0.1.0-experimental.11
 
-* Fixed setting an api to null in Java.
+* Fixed setting an API to null in Java.
 
 ## 0.1.0-experimental.10
 

packages/pigeon/example/app/lib/src/messages.g.dart

@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 // Autogenerated from Pigeon, do not edit directly.
 // See also: https://pub.dev/packages/pigeon
-// ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis, prefer_null_aware_operators, omit_local_variable_types, unused_shown_name, unnecessary_import
+// ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis, prefer_null_aware_operators, omit_local_variable_types, unused_shown_name, unnecessary_import, no_leading_underscores_for_local_identifiers
 
 import 'dart:async';
 import 'dart:typed_data' show Float64List, Int32List, Int64List, Uint8List;
@@ -98,111 +98,118 @@ class ExampleHostApi {
   /// available for dependency injection.  If it is left null, the default
   /// BinaryMessenger will be used which routes to the host platform.
   ExampleHostApi({BinaryMessenger? binaryMessenger})
-      : _binaryMessenger = binaryMessenger;
-  final BinaryMessenger? _binaryMessenger;
+      : __pigeon_binaryMessenger = binaryMessenger;
+  final BinaryMessenger? __pigeon_binaryMessenger;
 
-  static const MessageCodec<Object?> codec = _ExampleHostApiCodec();
+  static const MessageCodec<Object?> pigeonChannelCodec =
+      _ExampleHostApiCodec();
 
   Future<String> getHostLanguage() async {
-    const String channelName =
+    const String __pigeon_channelName =
         'dev.flutter.pigeon.pigeon_example_package.ExampleHostApi.getHostLanguage';
-    final BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(
-      channelName,
-      codec,
-      binaryMessenger: _binaryMessenger,
+    final BasicMessageChannel<Object?> __pigeon_channel =
+        BasicMessageChannel<Object?>(
+      __pigeon_channelName,
+      pigeonChannelCodec,
+      binaryMessenger: __pigeon_binaryMessenger,
     );
-    final List<Object?>? replyList = await channel.send(null) as List<Object?>?;
-    if (replyList == null) {
-      throw _createConnectionError(channelName);
-    } else if (replyList.length > 1) {
+    final List<Object?>? __pigeon_replyList =
+        await __pigeon_channel.send(null) as List<Object?>?;
+    if (__pigeon_replyList == null) {
+      throw _createConnectionError(__pigeon_channelName);
+    } else if (__pigeon_replyList.length > 1) {
       throw PlatformException(
-        code: replyList[0]! as String,
-        message: replyList[1] as String?,
-        details: replyList[2],
+        code: __pigeon_replyList[0]! as String,
+        message: __pigeon_replyList[1] as String?,
+        details: __pigeon_replyList[2],
       );
-    } else if (replyList[0] == null) {
+    } else if (__pigeon_replyList[0] == null) {
       throw PlatformException(
         code: 'null-error',
         message: 'Host platform returned null value for non-null return value.',
       );
     } else {
-      return (replyList[0] as String?)!;
+      return (__pigeon_replyList[0] as String?)!;
     }
   }
 
-  Future<int> add(int arg_a, int arg_b) async {
-    const String channelName =
+  Future<int> add(int a, int b) async {
+    const String __pigeon_channelName =
         'dev.flutter.pigeon.pigeon_example_package.ExampleHostApi.add';
-    final BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(
-      channelName,
-      codec,
-      binaryMessenger: _binaryMessenger,
+    final BasicMessageChannel<Object?> __pigeon_channel =
+        BasicMessageChannel<Object?>(
+      __pigeon_channelName,
+      pigeonChannelCodec,
+      binaryMessenger: __pigeon_binaryMessenger,
     );
-    final List<Object?>? replyList =
-        await channel.send(<Object?>[arg_a, arg_b]) as List<Object?>?;
-    if (replyList == null) {
-      throw _createConnectionError(channelName);
-    } else if (replyList.length > 1) {
+    final List<Object?>? __pigeon_replyList =
+        await __pigeon_channel.send(<Object?>[a, b]) as List<Object?>?;
+    if (__pigeon_replyList == null) {
+      throw _createConnectionError(__pigeon_channelName);
+    } else if (__pigeon_replyList.length > 1) {
       throw PlatformException(
-        code: replyList[0]! as String,
-        message: replyList[1] as String?,
-        details: replyList[2],
+        code: __pigeon_replyList[0]! as String,
+        message: __pigeon_replyList[1] as String?,
+        details: __pigeon_replyList[2],
       );
-    } else if (replyList[0] == null) {
+    } else if (__pigeon_replyList[0] == null) {
       throw PlatformException(
         code: 'null-error',
         message: 'Host platform returned null value for non-null return value.',
       );
     } else {
-      return (replyList[0] as int?)!;
+      return (__pigeon_replyList[0] as int?)!;
     }
   }
 
-  Future<bool> sendMessage(MessageData arg_message) async {
-    const String channelName =
+  Future<bool> sendMessage(MessageData message) async {
+    const String __pigeon_channelName =
         'dev.flutter.pigeon.pigeon_example_package.ExampleHostApi.sendMessage';
-    final BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(
-      channelName,
-      codec,
-      binaryMessenger: _binaryMessenger,
+    final BasicMessageChannel<Object?> __pigeon_channel =
+        BasicMessageChannel<Object?>(
+      __pigeon_channelName,
+      pigeonChannelCodec,
+      binaryMessenger: __pigeon_binaryMessenger,
     );
-    final List<Object?>? replyList =
-        await channel.send(<Object?>[arg_message]) as List<Object?>?;
-    if (replyList == null) {
-      throw _createConnectionError(channelName);
-    } else if (replyList.length > 1) {
+    final List<Object?>? __pigeon_replyList =
+        await __pigeon_channel.send(<Object?>[message]) as List<Object?>?;
+    if (__pigeon_replyList == null) {
+      throw _createConnectionError(__pigeon_channelName);
+    } else if (__pigeon_replyList.length > 1) {
       throw PlatformException(
-        code: replyList[0]! as String,
-        message: replyList[1] as String?,
-        details: replyList[2],
+        code: __pigeon_replyList[0]! as String,
+        message: __pigeon_replyList[1] as String?,
+        details: __pigeon_replyList[2],
       );
-    } else if (replyList[0] == null) {
+    } else if (__pigeon_replyList[0] == null) {
       throw PlatformException(
         code: 'null-error',
         message: 'Host platform returned null value for non-null return value.',
       );
     } else {
-      return (replyList[0] as bool?)!;
+      return (__pigeon_replyList[0] as bool?)!;
     }
   }
 }
 
 abstract class MessageFlutterApi {
-  static const MessageCodec<Object?> codec = StandardMessageCodec();
+  static const MessageCodec<Object?> pigeonChannelCodec =
+      StandardMessageCodec();
 
   String flutterMethod(String? aString);
 
   static void setup(MessageFlutterApi? api,
       {BinaryMessenger? binaryMessenger}) {
     {
-      final BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(
+      final BasicMessageChannel<Object?> __pigeon_channel = BasicMessageChannel<
+              Object?>(
           'dev.flutter.pigeon.pigeon_example_package.MessageFlutterApi.flutterMethod',
-          codec,
+          pigeonChannelCodec,
           binaryMessenger: binaryMessenger);
       if (api == null) {
-        channel.setMessageHandler(null);
+        __pigeon_channel.setMessageHandler(null);
       } else {
-        channel.setMessageHandler((Object? message) async {
+        __pigeon_channel.setMessageHandler((Object? message) async {
           assert(message != null,
               'Argument for dev.flutter.pigeon.pigeon_example_package.MessageFlutterApi.flutterMethod was null.');
           final List<Object?> args = (message as List<Object?>?)!;