[pigeon] fixed error returning errors from async void(void) functions (#380)

packages/pigeon/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.2.3
+
+* bugfix in iOS async handlers of functions with no arguments.
+
 ## 0.2.2
 
 * Added support for enums.

packages/pigeon/lib/generator_tools.dart

@@ -8,7 +8,7 @@ import 'dart:mirrors';
 import 'ast.dart';
 
 /// The current version of pigeon. This must match the version in pubspec.yaml.
-const String pigeonVersion = '0.2.2';
+const String pigeonVersion = '0.2.3';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {

packages/pigeon/lib/objc_generator.dart

@@ -283,7 +283,7 @@ void _writeHostApiSource(Indent indent, ObjcOptions options, Api api) {
             }
             if (func.isAsynchronous) {
               if (func.returnType == 'void') {
-                const String callback = 'callback(error);';
+                const String callback = 'callback(wrapResult(nil, error));';
                 if (func.argType == 'void') {
                   indent.writeScoped(
                       '[api ${func.name}:^(FlutterError *_Nullable error) {',

packages/pigeon/platform_tests/ios_unit_tests/ios/RunnerTests/AsyncHandlersTest.m

@@ -60,6 +60,7 @@
 ///////////////////////////////////////////////////////////////////////////////////////////
 @interface MockApi2Host : NSObject<Api2Host>
 @property(nonatomic, copy) NSNumber* output;
+@property(nonatomic, retain) FlutterError* voidVoidError;
 @end
 
 ///////////////////////////////////////////////////////////////////////////////////////////
@@ -76,6 +77,10 @@
   }
 }
 
+- (void)voidVoid:(nonnull void (^)(FlutterError* _Nullable))completion {
+  completion(self.voidVoidError);
+}
+
 @end
 
 ///////////////////////////////////////////////////////////////////////////////////////////
@@ -100,6 +105,42 @@
   [self waitForExpectationsWithTimeout:1.0 handler:nil];
 }
 
+- (void)testAsyncFlutter2HostVoidVoid {
+  MockBinaryMessenger* binaryMessenger = [[MockBinaryMessenger alloc] init];
+  MockApi2Host* mockApi2Host = [[MockApi2Host alloc] init];
+  mockApi2Host.output = @(2);
+  Api2HostSetup(binaryMessenger, mockApi2Host);
+  NSString* channelName = @"dev.flutter.pigeon.Api2Host.voidVoid";
+  XCTAssertNotNil(binaryMessenger.handlers[channelName]);
+
+  XCTestExpectation* expectation = [self expectationWithDescription:@"voidvoid callback"];
+  binaryMessenger.handlers[channelName](nil, ^(NSData* data) {
+    NSDictionary* outputMap = [binaryMessenger.codec decode:data];
+    XCTAssertEqualObjects(outputMap[@"result"], [NSNull null]);
+    XCTAssertEqualObjects(outputMap[@"error"], [NSNull null]);
+    [expectation fulfill];
+  });
+  [self waitForExpectationsWithTimeout:1.0 handler:nil];
+}
+
+- (void)testAsyncFlutter2HostVoidVoidError {
+  MockBinaryMessenger* binaryMessenger = [[MockBinaryMessenger alloc] init];
+  MockApi2Host* mockApi2Host = [[MockApi2Host alloc] init];
+  mockApi2Host.voidVoidError = [FlutterError errorWithCode:@"code" message:@"message" details:nil];
+  Api2HostSetup(binaryMessenger, mockApi2Host);
+  NSString* channelName = @"dev.flutter.pigeon.Api2Host.voidVoid";
+  XCTAssertNotNil(binaryMessenger.handlers[channelName]);
+
+  XCTestExpectation* expectation = [self expectationWithDescription:@"voidvoid callback"];
+  binaryMessenger.handlers[channelName](nil, ^(NSData* data) {
+    NSDictionary* outputMap = [binaryMessenger.codec decode:data];
+    XCTAssertNotNil(outputMap[@"error"]);
+    XCTAssertEqualObjects(outputMap[@"error"][@"code"], mockApi2Host.voidVoidError.code);
+    [expectation fulfill];
+  });
+  [self waitForExpectationsWithTimeout:1.0 handler:nil];
+}
+
 - (void)testAsyncFlutter2Host {
   MockBinaryMessenger* binaryMessenger = [[MockBinaryMessenger alloc] init];
   MockApi2Host* mockApi2Host = [[MockApi2Host alloc] init];

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/master/packages/pigeon
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3Apigeon
-version: 0.2.2 # This must match the version in lib/generator_tools.dart
+version: 0.2.3 # This must match the version in lib/generator_tools.dart
 
 environment:
   sdk: '>=2.12.0 <3.0.0'