Forward errors through sendRequest for Peers (#2225)

Avoid a future that does not complete. Forward errors through both
the peer and client forwarders.

Author: d-markey

pkgs/json_rpc_2/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 4.1.0-wip
+
+* Forward errors within `Peer` when it is acting as a client.
+
 ## 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

@@ -161,6 +161,7 @@ class Peer implements Client, Server {
       }
     }, 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: 4.1.0-wip
 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(