Revert "Remove some `dynamic's. (#75820)" (#76232)

This reverts commit 2d9a01a8.

packages/flutter/lib/src/services/message_codec.dart

@@ -29,7 +29,7 @@ abstract class MessageCodec<T> {
   /// Decodes the specified [message] from binary.
   ///
   /// Returns null if the message is null.
-  T? decodeMessage(ByteData? message);
+  T decodeMessage(ByteData? message);
 }
 
 /// An command object representing the invocation of a named method.
@@ -73,22 +73,16 @@ abstract class MethodCodec {
   ///
   /// Throws [PlatformException], if [envelope] represents an error, otherwise
   /// returns the enveloped result.
-  ///
-  /// The type returned from [decodeEnvelope] is `dynamic` (not `Object?`),
-  /// which means *no type checking is performed on its return value*. It is
-  /// strongly recommended that the return value be immediately cast to a known
-  /// type to prevent runtime errors due to typos that the type checker could
-  /// otherwise catch.
   dynamic decodeEnvelope(ByteData envelope);
 
   /// Encodes a successful [result] into a binary envelope.
-  ByteData encodeSuccessEnvelope(Object? result);
+  ByteData encodeSuccessEnvelope(dynamic result);
 
   /// Encodes an error result into a binary envelope.
   ///
   /// The specified error [code], human-readable error [message] and error
   /// [details] correspond to the fields of [PlatformException].
-  ByteData encodeErrorEnvelope({ required String code, String? message, Object? details});
+  ByteData encodeErrorEnvelope({ required String code, String? message, dynamic details});
 }
 
 
@@ -123,7 +117,7 @@ class PlatformException implements Exception {
   final String? message;
 
   /// Error details, possibly null.
-  final Object? details;
+  final dynamic details;
 
   /// Native stacktrace for the error, possibly null.
   /// This is strictly for native platform stacktrace.

packages/flutter/lib/src/services/platform_channel.dart

@@ -52,7 +52,7 @@ class BasicMessageChannel<T> {
   ///
   /// Returns a [Future] which completes to the received response, which may
   /// be null.
-  Future<T?> send(T message) async {
+  Future<T> send(T message) async {
     return codec.decodeMessage(await binaryMessenger.send(name, codec.encodeMessage(message)));
   }
 
@@ -65,7 +65,7 @@ class BasicMessageChannel<T> {
   ///
   /// The handler's return value is sent back to the platform plugins as a
   /// message reply. It may be null.
-  void setMessageHandler(Future<T> Function(T? message)? handler) {
+  void setMessageHandler(Future<T> Function(T message)? handler) {
     if (handler == null) {
       binaryMessenger.setMessageHandler(name, null);
     } else {
@@ -86,7 +86,7 @@ class BasicMessageChannel<T> {
   ///
   /// This is intended for testing. Messages intercepted in this manner are not
   /// sent to platform plugins.
-  void setMockMessageHandler(Future<T> Function(T? message)? handler) {
+  void setMockMessageHandler(Future<T> Function(T message)? handler) {
     if (handler == null) {
       binaryMessenger.setMockMessageHandler(name, null);
     } else {

packages/flutter/lib/src/services/restoration.dart

@@ -226,7 +226,7 @@ class RestorationManager extends ChangeNotifier {
   bool _isReplacing = false;
 
   Future<void> _getRootBucketFromEngine() async {
-    final Map<Object?, Object?>? config = await SystemChannels.restoration.invokeMethod<Map<Object?, Object?>>('get');
+    final Map<dynamic, dynamic>? config = await SystemChannels.restoration.invokeMethod<Map<dynamic, dynamic>>('get');
     if (_pendingRootBucket == null) {
       // The restoration data was obtained via other means (e.g. by calling
       // [handleRestorationDataUpdate] while the request to the engine was
@@ -237,9 +237,9 @@ class RestorationManager extends ChangeNotifier {
     _parseAndHandleRestorationUpdateFromEngine(config);
   }
 
-  void _parseAndHandleRestorationUpdateFromEngine(Map<Object?, Object?>? update) {
+  void _parseAndHandleRestorationUpdateFromEngine(Map<dynamic, dynamic>? update) {
     handleRestorationUpdateFromEngine(
-      enabled: update != null && update['enabled']! as bool,
+      enabled: update != null && update['enabled'] as bool,
       data: update == null ? null : update['data'] as Uint8List?,
     );
   }
@@ -305,25 +305,25 @@ class RestorationManager extends ChangeNotifier {
     );
   }
 
-  Future<Object?> _methodHandler(MethodCall call) async {
+  Future<dynamic> _methodHandler(MethodCall call) async {
     switch (call.method) {
       case 'push':
-        _parseAndHandleRestorationUpdateFromEngine(call.arguments as Map<Object?, Object?>);
+        _parseAndHandleRestorationUpdateFromEngine(call.arguments as Map<dynamic, dynamic>);
         break;
       default:
         throw UnimplementedError("${call.method} was invoked but isn't implemented by $runtimeType");
     }
   }
 
-  Map<Object?, Object?>? _decodeRestorationData(Uint8List? data) {
+  Map<dynamic, dynamic>? _decodeRestorationData(Uint8List? data) {
     if (data == null) {
       return null;
     }
     final ByteData encoded = data.buffer.asByteData(data.offsetInBytes, data.lengthInBytes);
-    return const StandardMessageCodec().decodeMessage(encoded) as Map<Object?, Object?>?;
+    return const StandardMessageCodec().decodeMessage(encoded) as Map<dynamic, dynamic>;
   }
 
-  Uint8List _encodeRestorationData(Map<Object?, Object?> data) {
+  Uint8List _encodeRestorationData(Map<dynamic, dynamic> data) {
     final ByteData encoded = const StandardMessageCodec().encodeMessage(data)!;
     return encoded.buffer.asUint8List(encoded.offsetInBytes, encoded.lengthInBytes);
   }
@@ -505,7 +505,7 @@ class RestorationBucket {
     required Object? debugOwner,
   }) : assert(restorationId != null),
        _restorationId = restorationId,
-       _rawData = <String, Object?>{} {
+       _rawData = <String, dynamic>{} {
     assert(() {
       _debugOwner = debugOwner;
       return true;
@@ -537,10 +537,10 @@ class RestorationBucket {
   /// The `manager` argument must not be null.
   RestorationBucket.root({
     required RestorationManager manager,
-    required Map<Object?, Object?>? rawData,
+    required Map<dynamic, dynamic>? rawData,
   }) : assert(manager != null),
        _manager = manager,
-       _rawData = rawData ?? <Object?, Object?>{},
+       _rawData = rawData ?? <dynamic, dynamic>{},
        _restorationId = 'root' {
     assert(() {
       _debugOwner = manager;
@@ -567,7 +567,7 @@ class RestorationBucket {
        assert(parent._rawChildren[restorationId] != null),
        _manager = parent._manager,
        _parent = parent,
-       _rawData = parent._rawChildren[restorationId]! as Map<Object?, Object?>,
+       _rawData = parent._rawChildren[restorationId] as Map<dynamic, dynamic>,
        _restorationId = restorationId {
     assert(() {
       _debugOwner = debugOwner;
@@ -578,7 +578,7 @@ class RestorationBucket {
   static const String _childrenMapKey = 'c';
   static const String _valuesMapKey = 'v';
 
-  final Map<Object?, Object?> _rawData;
+  final Map<dynamic, dynamic> _rawData;
 
   /// The owner of the bucket that was provided when the bucket was claimed via
   /// [claimChild].
@@ -616,9 +616,9 @@ class RestorationBucket {
   String _restorationId;
 
   // Maps a restoration ID to the raw map representation of a child bucket.
-  Map<Object?, Object?> get _rawChildren => _rawData.putIfAbsent(_childrenMapKey, () => <Object?, Object?>{})! as Map<Object?, Object?>;
+  Map<dynamic, dynamic> get _rawChildren => _rawData.putIfAbsent(_childrenMapKey, () => <dynamic, dynamic>{}) as Map<dynamic, dynamic>;
   // Maps a restoration ID to a value that is stored in this bucket.
-  Map<Object?, Object?> get _rawValues => _rawData.putIfAbsent(_valuesMapKey, () => <Object?, Object?>{})! as Map<Object?, Object?>;
+  Map<dynamic, dynamic> get _rawValues => _rawData.putIfAbsent(_valuesMapKey, () => <dynamic, dynamic>{}) as Map<dynamic, dynamic>;
 
   // Get and store values.
 

packages/flutter/test/services/message_codecs_testing.dart

@@ -17,13 +17,13 @@ void checkEncoding<T>(MessageCodec<T> codec, T message, List<int> expectedBytes)
 
 void checkEncodeDecode<T>(MessageCodec<T> codec, T message) {
   final ByteData? encoded = codec.encodeMessage(message);
-  final T? decoded = codec.decodeMessage(encoded);
+  final T decoded = codec.decodeMessage(encoded);
   if (message == null) {
     expect(encoded, isNull);
     expect(decoded, isNull);
   } else {
     expect(deepEquals(message, decoded), isTrue);
-    final ByteData? encodedAgain = codec.encodeMessage(decoded as T);
+    final ByteData? encodedAgain = codec.encodeMessage(decoded);
     expect(
       encodedAgain!.buffer.asUint8List(),
       orderedEquals(encoded!.buffer.asUint8List()),

packages/flutter_web_plugins/test/plugin_registry_test.dart

@@ -56,7 +56,7 @@ void main() {
       final List<String> loggedMessages = <String>[];
       ServicesBinding.instance!.defaultBinaryMessenger
           .setMessageHandler('test_send', (ByteData? data) {
-        loggedMessages.add(codec.decodeMessage(data)! as String);
+        loggedMessages.add(codec.decodeMessage(data) as String);
         return Future<ByteData?>.value(null);
       });