Attempt at fixing https://github.com/dart-lang/tools/issues/2202.

pkgs/json_rpc_2/CHANGELOG.md

@@ -1,3 +1,9 @@
+## 4.0.0-tentative
+
+* Enable tests for Web-platforms.
+* Added a test for peer failure in "like a client" scenario. Without this fix, `peer.sendRequest()` never completes and the test times out.
+* The fix consists in forwarding errors to both the client and the server.
+
 ## 4.0.0
 
 * Add custom ID generator option to clients, which allows for `String` ids.

pkgs/json_rpc_2/dart_test.yaml

@@ -0,0 +1,7 @@
+platforms:
+  - vm
+  - chrome
+
+compilers:
+  - dart2js
+  - dart2wasm

pkgs/json_rpc_2/lib/src/peer.dart

@@ -69,10 +69,11 @@ class Peer implements Client, Server {
     bool strictProtocolChecks = true,
     Object Function()? idGenerator,
   }) : this.withoutJson(
-            jsonDocument.bind(channel).transform(respondToFormatExceptions),
-            onUnhandledError: onUnhandledError,
-            strictProtocolChecks: strictProtocolChecks,
-            idGenerator: idGenerator);
+          jsonDocument.bind(channel).transform(respondToFormatExceptions),
+          onUnhandledError: onUnhandledError,
+          strictProtocolChecks: strictProtocolChecks,
+          idGenerator: idGenerator,
+        );
 
   /// Creates a [Peer] that communicates using decoded messages over [_channel].
   ///
@@ -93,20 +94,21 @@ class Peer implements Client, Server {
   /// If [idGenerator] is passed, it will be called to generate an ID for each
   /// request. Defaults to an auto-incrementing `int`. The value returned must
   /// be either an `int` or `String`.
-  Peer.withoutJson(this._channel,
-      {ErrorCallback? onUnhandledError,
-      bool strictProtocolChecks = true,
-      Object Function()? idGenerator}) {
+  Peer.withoutJson(
+    this._channel, {
+    ErrorCallback? onUnhandledError,
+    bool strictProtocolChecks = true,
+    Object Function()? idGenerator,
+  }) {
     _server = Server.withoutJson(
-        StreamChannel(_serverIncomingForwarder.stream, _channel.sink),
-        onUnhandledError: onUnhandledError,
-        strictProtocolChecks: strictProtocolChecks);
+      StreamChannel(_serverIncomingForwarder.stream, _channel.sink),
+      onUnhandledError: onUnhandledError,
+      strictProtocolChecks: strictProtocolChecks,
+    );
     _client = Client.withoutJson(
-        StreamChannel(
-          _clientIncomingForwarder.stream,
-          _channel.sink,
-        ),
-        idGenerator: idGenerator);
+      StreamChannel(_clientIncomingForwarder.stream, _channel.sink),
+      idGenerator: idGenerator,
+    );
   }
 
   // Client methods.
@@ -138,30 +140,35 @@ class Peer implements Client, Server {
   Future listen() {
     _client.listen();
     _server.listen();
-    _channel.stream.listen((message) {
-      if (message is Map) {
-        if (message.containsKey('result') || message.containsKey('error')) {
-          _clientIncomingForwarder.add(message);
-        } else {
-          _serverIncomingForwarder.add(message);
-        }
-      } else if (message is List &&
-          message.isNotEmpty &&
-          message.first is Map) {
-        if (message.first.containsKey('result') ||
-            message.first.containsKey('error')) {
-          _clientIncomingForwarder.add(message);
+    _channel.stream.listen(
+      (message) {
+        if (message is Map) {
+          if (message.containsKey('result') || message.containsKey('error')) {
+            _clientIncomingForwarder.add(message);
+          } else {
+            _serverIncomingForwarder.add(message);
+          }
+        } else if (message is List &&
+            message.isNotEmpty &&
+            message.first is Map) {
+          if (message.first.containsKey('result') ||
+              message.first.containsKey('error')) {
+            _clientIncomingForwarder.add(message);
+          } else {
+            _serverIncomingForwarder.add(message);
+          }
         } else {
+          // Non-Map and -List messages are ill-formed, so we pass them to the
+          // server since it knows how to send error responses.
           _serverIncomingForwarder.add(message);
         }
-      } else {
-        // Non-Map and -List messages are ill-formed, so we pass them to the
-        // server since it knows how to send error responses.
-        _serverIncomingForwarder.add(message);
-      }
-    }, onError: (Object error, StackTrace stackTrace) {
-      _serverIncomingForwarder.addError(error, stackTrace);
-    }, onDone: close);
+      },
+      onError: (Object error, StackTrace stackTrace) {
+        _serverIncomingForwarder.addError(error, stackTrace);
+        _clientIncomingForwarder.addError(error, stackTrace);
+      },
+      onDone: close,
+    );
     return done;
   }
 

pkgs/json_rpc_2/pubspec.yaml

@@ -1,5 +1,5 @@
 name: json_rpc_2
-version: 4.0.0
+version: 4.0.0-tentative
 description: >-
   Utilities to write a client or server using the JSON-RPC 2.0 spec.
 repository: https://github.com/dart-lang/tools/tree/main/pkgs/json_rpc_2

pkgs/json_rpc_2/test/peer_test.dart

@@ -45,6 +45,27 @@ void main() {
           peer.sendRequest('foo', {'bar': 'baz'}), completion(equals('qux')));
     });
 
+    test('can send a message and receive an error', () {
+      expect(outgoing.first.then((request) {
+        expect(
+            request,
+            equals({
+              'jsonrpc': '2.0',
+              'method': 'foo',
+              'params': {'bar': 'baz'},
+              'id': 0
+            }));
+        incoming.addError(Exception('failure'));
+      }), completes);
+
+      peer.listen().ignore();
+
+      expect(
+          peer.sendRequest('foo', {'bar': 'baz'}),
+          throwsA(isA<StateError>().having(($) => $.message, 'message',
+              contains('client closed with pending request "foo"'))));
+    });
+
     test('can send a batch of messages and receive a batch of responses', () {
       expect(outgoing.first.then((request) {
         expect(