[pigeon] Fix Object arguments in Swift and C++

packages/pigeon/CHANGELOG.md

@@ -1,3 +1,9 @@
+## 4.2.16
+
+* [swift] Fixes warnings with `Object` parameters.
+* [dart] Fixes warnings with `Object` return values.
+* [c++] Generation of APIs that use `Object` no longer fails.
+
 ## 4.2.15
 
 * Relocates generator classes. (Reverted)

packages/pigeon/lib/cpp_generator.dart

@@ -547,6 +547,11 @@ const flutter::StandardMessageCodec& ${api.name}::GetCodec() {
                       // ... then declare the arg as a reference to that local.
                       indent.writeln(
                           'const auto* $argName = $encodableArgName.IsNull() ? nullptr : &$valueVarName;');
+                    } else if (hostType.datatype == 'flutter::EncodableValue') {
+                      // Generic objects just pass the EncodableValue through
+                      // directly.
+                      indent.writeln(
+                          'const auto* $argName = &$encodableArgName;');
                     } else if (hostType.isBuiltin) {
                       indent.writeln(
                           'const auto* $argName = std::get_if<${hostType.datatype}>(&$encodableArgName);');
@@ -564,6 +569,13 @@ const flutter::StandardMessageCodec& ${api.name}::GetCodec() {
                       // requires an int64_t so that it can handle any case.
                       indent.writeln(
                           'const int64_t $argName = $encodableArgName.LongValue();');
+                    } else if (hostType.datatype == 'flutter::EncodableValue') {
+                      // Generic objects just pass the EncodableValue through
+                      // directly. This creates an alias just to avoid having to
+                      // special-case the argName/encodableArgName distinction
+                      // at a higher level.
+                      indent
+                          .writeln('const auto& $argName = $encodableArgName;');
                     } else if (hostType.isBuiltin) {
                       indent.writeln(
                           'const auto& $argName = std::get<${hostType.datatype}>($encodableArgName);');
@@ -902,6 +914,7 @@ String? _baseCppTypeForBuiltinDartType(TypeDeclaration type) {
     'Float64List': 'std::vector<double>',
     'Map': 'flutter::EncodableMap',
     'List': 'flutter::EncodableList',
+    'Object': 'flutter::EncodableValue',
   };
   if (cppTypeForDartTypeMap.containsKey(type.baseName)) {
     return cppTypeForDartTypeMap[type.baseName];
@@ -931,6 +944,8 @@ String _unownedArgumentType(HostDatatype type) {
   if (isString || _isPodType(type)) {
     return type.isNullable ? 'const $baseType*' : baseType;
   }
+  // TODO(stuartmorgan): Consider special-casing `Object?` here, so that there
+  // aren't two ways of representing null (nullptr or an isNull EncodableValue).
   return type.isNullable ? 'const $baseType*' : 'const $baseType&';
 }
 

packages/pigeon/lib/dart_generator.dart

@@ -230,13 +230,17 @@ final BinaryMessenger? _binaryMessenger;
           indent.writeln('binaryMessenger: _binaryMessenger);');
         });
         final String returnType = _makeGenericTypeArguments(func.returnType);
-        final String castCall = _makeGenericCastCall(func.returnType);
+        final String genericCastCall = _makeGenericCastCall(func.returnType);
         const String accessor = 'replyList[0]';
-        final String nullHandler =
-            func.returnType.isNullable ? (castCall.isEmpty ? '' : '?') : '!';
+        // Avoid warnings from pointlessly casting to `Object?`.
+        final String nullablyTypedAccessor =
+            returnType == 'Object' ? accessor : '($accessor as $returnType?)';
+        final String nullHandler = func.returnType.isNullable
+            ? (genericCastCall.isEmpty ? '' : '?')
+            : '!';
         final String returnStatement = func.returnType.isVoid
             ? 'return;'
-            : 'return ($accessor as $returnType?)$nullHandler$castCall;';
+            : 'return $nullablyTypedAccessor$nullHandler$genericCastCall;';
         indent.format('''
 final List<Object?>? replyList =
 \t\tawait channel.send($sendArgument) as List<Object?>?;

packages/pigeon/lib/generator_tools.dart

@@ -9,7 +9,7 @@ import 'dart:mirrors';
 import 'ast.dart';
 
 /// The current version of pigeon. This must match the version in pubspec.yaml.
-const String pigeonVersion = '4.2.15';
+const String pigeonVersion = '4.2.16';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {

packages/pigeon/lib/swift_generator.dart

@@ -365,6 +365,9 @@ String _castForceUnwrap(String value, TypeDeclaration type, Root root) {
     final String nullableConditionPrefix =
         type.isNullable ? '$value == nil ? nil : ' : '';
     return '$nullableConditionPrefix${_swiftTypeForDartType(type)}(rawValue: $value as! Int)$forceUnwrap';
+  } else if (type.baseName == 'Object') {
+    // Special-cased to avoid warnings about using 'as' with Any.
+    return type.isNullable ? value : '$value!';
   } else {
     final String castUnwrap = type.isNullable ? '?' : '!';
     return '$value as$castUnwrap ${_swiftTypeForDartType(type)}';

packages/pigeon/pigeons/core_tests.dart

@@ -125,6 +125,10 @@ abstract class HostIntegrationCoreApi {
   @ObjCSelector('echoUint8List:')
   Uint8List echoUint8List(Uint8List aUint8List);
 
+  /// Returns the passed in generic Object.
+  @ObjCSelector('echoObject:')
+  Object echoObject(Object anObject);
+
   // ========== Syncronous nullable method tests ==========
 
   /// Returns the inner `aString` value from the wrapped object, to test
@@ -162,6 +166,10 @@ abstract class HostIntegrationCoreApi {
   @ObjCSelector('echoNullableUint8List:')
   Uint8List? echoNullableUint8List(Uint8List? aNullableUint8List);
 
+  /// Returns the passed in generic Object.
+  @ObjCSelector('echoNullableObject:')
+  Object? echoNullableObject(Object? aNullableObject);
+
   // ========== Asyncronous method tests ==========
 
   /// A no-op function taking no arguments and returning no value, to sanity

packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/AlternateLanguageTestPlugin.java

@@ -72,6 +72,11 @@ public byte[] echoUint8List(@NonNull byte[] aUint8List) {
     return aUint8List;
   }
 
+  @Override
+  public @NonNull Object echoObject(@NonNull Object anObject) {
+    return anObject;
+  }
+
   @Override
   public @Nullable String extractNestedNullableString(@NonNull AllNullableTypesWrapper wrapper) {
     return wrapper.getValues().getANullableString();
@@ -124,6 +129,11 @@ public byte[] echoUint8List(@NonNull byte[] aUint8List) {
     return aNullableUint8List;
   }
 
+  @Override
+  public @Nullable Object echoNullableObject(@Nullable Object aNullableObject) {
+    return aNullableObject;
+  }
+
   @Override
   public void noopAsync(Result<Void> result) {
     result.success(null);

packages/pigeon/platform_tests/alternate_language_test_plugin/android/src/main/java/com/example/alternate_language_test_plugin/CoreTests.java

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v4.2.15), do not edit directly.
+// Autogenerated from Pigeon (v4.2.16), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 
 package com.example.alternate_language_test_plugin;
@@ -713,12 +713,9 @@ protected Object readValueOfType(byte type, @NonNull ByteBuffer buffer) {
           return AllNullableTypes.fromList((ArrayList<Object>) readValue(buffer));
 
         case (byte) 129:
-          return AllNullableTypes.fromList((ArrayList<Object>) readValue(buffer));
-
-        case (byte) 130:
           return AllNullableTypesWrapper.fromList((ArrayList<Object>) readValue(buffer));
 
-        case (byte) 131:
+        case (byte) 130:
           return AllTypes.fromList((ArrayList<Object>) readValue(buffer));
 
         default:
@@ -731,14 +728,11 @@ protected void writeValue(@NonNull ByteArrayOutputStream stream, Object value) {
       if (value instanceof AllNullableTypes) {
         stream.write(128);
         writeValue(stream, ((AllNullableTypes) value).toList());
-      } else if (value instanceof AllNullableTypes) {
-        stream.write(129);
-        writeValue(stream, ((AllNullableTypes) value).toList());
       } else if (value instanceof AllNullableTypesWrapper) {
-        stream.write(130);
+        stream.write(129);
         writeValue(stream, ((AllNullableTypesWrapper) value).toList());
       } else if (value instanceof AllTypes) {
-        stream.write(131);
+        stream.write(130);
         writeValue(stream, ((AllTypes) value).toList());
       } else {
         super.writeValue(stream, value);
@@ -780,6 +774,9 @@ public interface HostIntegrationCoreApi {
     /** Returns the passed in Uint8List. */
     @NonNull
     byte[] echoUint8List(@NonNull byte[] aUint8List);
+    /** Returns the passed in generic Object. */
+    @NonNull
+    Object echoObject(@NonNull Object anObject);
     /**
      * Returns the inner `aString` value from the wrapped object, to test sending of nested objects.
      */
@@ -811,6 +808,9 @@ AllNullableTypes sendMultipleNullableTypes(
     /** Returns the passed in Uint8List. */
     @Nullable
     byte[] echoNullableUint8List(@Nullable byte[] aNullableUint8List);
+    /** Returns the passed in generic Object. */
+    @Nullable
+    Object echoNullableObject(@Nullable Object aNullableObject);
     /**
      * A no-op function taking no arguments and returning no value, to sanity test basic
      * asynchronous calling.
@@ -1072,6 +1072,35 @@ static void setup(BinaryMessenger binaryMessenger, HostIntegrationCoreApi api) {
           channel.setMessageHandler(null);
         }
       }
+      {
+        BasicMessageChannel<Object> channel =
+            new BasicMessageChannel<>(
+                binaryMessenger,
+                "dev.flutter.pigeon.HostIntegrationCoreApi.echoObject",
+                getCodec());
+        if (api != null) {
+          channel.setMessageHandler(
+              (message, reply) -> {
+                ArrayList wrapped = new ArrayList<>();
+                try {
+                  ArrayList<Object> args = (ArrayList<Object>) message;
+                  assert args != null;
+                  Object anObjectArg = args.get(0);
+                  if (anObjectArg == null) {
+                    throw new NullPointerException("anObjectArg unexpectedly null.");
+                  }
+                  Object output = api.echoObject(anObjectArg);
+                  wrapped.add(0, output);
+                } catch (Error | RuntimeException exception) {
+                  ArrayList<Object> wrappedError = wrapError(exception);
+                  wrapped = wrappedError;
+                }
+                reply.reply(wrapped);
+              });
+        } else {
+          channel.setMessageHandler(null);
+        }
+      }
       {
         BasicMessageChannel<Object> channel =
             new BasicMessageChannel<>(
@@ -1292,6 +1321,32 @@ static void setup(BinaryMessenger binaryMessenger, HostIntegrationCoreApi api) {
           channel.setMessageHandler(null);
         }
       }
+      {
+        BasicMessageChannel<Object> channel =
+            new BasicMessageChannel<>(
+                binaryMessenger,
+                "dev.flutter.pigeon.HostIntegrationCoreApi.echoNullableObject",
+                getCodec());
+        if (api != null) {
+          channel.setMessageHandler(
+              (message, reply) -> {
+                ArrayList wrapped = new ArrayList<>();
+                try {
+                  ArrayList<Object> args = (ArrayList<Object>) message;
+                  assert args != null;
+                  Object aNullableObjectArg = args.get(0);
+                  Object output = api.echoNullableObject(aNullableObjectArg);
+                  wrapped.add(0, output);
+                } catch (Error | RuntimeException exception) {
+                  ArrayList<Object> wrappedError = wrapError(exception);
+                  wrapped = wrappedError;
+                }
+                reply.reply(wrapped);
+              });
+        } else {
+          channel.setMessageHandler(null);
+        }
+      }
       {
         BasicMessageChannel<Object> channel =
             new BasicMessageChannel<>(

packages/pigeon/platform_tests/alternate_language_test_plugin/ios/Classes/AlternateLanguageTestPlugin.m

@@ -63,6 +63,10 @@ - (nullable FlutterStandardTypedData *)echoUint8List:(FlutterStandardTypedData *
   return aUint8List;
 }
 
+- (nullable id)echoObject:(id)anObject error:(FlutterError *_Nullable *_Nonnull)error {
+  return anObject;
+}
+
 - (nullable NSString *)extractNestedNullableStringFrom:(AllNullableTypesWrapper *)wrapper
                                                  error:(FlutterError *_Nullable *_Nonnull)error {
   return wrapper.values.aNullableString;
@@ -114,6 +118,11 @@ - (nullable NSString *)echoNullableString:(nullable NSString *)aNullableString
   return aNullableUint8List;
 }
 
+- (nullable id)echoNullableObject:(nullable id)aNullableObject
+                            error:(FlutterError *_Nullable *_Nonnull)error {
+  return aNullableObject;
+}
+
 - (void)noopAsyncWithCompletion:(void (^)(FlutterError *_Nullable))completion {
   completion(nil);
 }

packages/pigeon/platform_tests/alternate_language_test_plugin/ios/Classes/CoreTests.gen.h

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v4.2.15), do not edit directly.
+// Autogenerated from Pigeon (v4.2.16), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 #import <Foundation/Foundation.h>
 @protocol FlutterBinaryMessenger;
@@ -131,6 +131,10 @@ NSObject<FlutterMessageCodec> *HostIntegrationCoreApiGetCodec(void);
 /// @return `nil` only when `error != nil`.
 - (nullable FlutterStandardTypedData *)echoUint8List:(FlutterStandardTypedData *)aUint8List
                                                error:(FlutterError *_Nullable *_Nonnull)error;
+/// Returns the passed in generic Object.
+///
+/// @return `nil` only when `error != nil`.
+- (nullable id)echoObject:(id)anObject error:(FlutterError *_Nullable *_Nonnull)error;
 /// Returns the inner `aString` value from the wrapped object, to test
 /// sending of nested objects.
 - (nullable NSString *)extractNestedNullableStringFrom:(AllNullableTypesWrapper *)wrapper
@@ -166,6 +170,9 @@ NSObject<FlutterMessageCodec> *HostIntegrationCoreApiGetCodec(void);
 - (nullable FlutterStandardTypedData *)
     echoNullableUint8List:(nullable FlutterStandardTypedData *)aNullableUint8List
                     error:(FlutterError *_Nullable *_Nonnull)error;
+/// Returns the passed in generic Object.
+- (nullable id)echoNullableObject:(nullable id)aNullableObject
+                            error:(FlutterError *_Nullable *_Nonnull)error;
 /// A no-op function taking no arguments and returning no value, to sanity
 /// test basic asynchronous calling.
 - (void)noopAsyncWithCompletion:(void (^)(FlutterError *_Nullable))completion;