Fix not reading to end of argument JSON on binding error (#2319)

Author: JamesNK

src/Microsoft.AspNetCore.SignalR.Protocols.Json/Protocol/JsonHubProtocol.cs

@@ -209,6 +209,7 @@ private HubMessage ParseMessage(Utf8BufferTextReader textReader, IInvocationBind
                                     case ArgumentsPropertyName:
                                         JsonUtils.CheckRead(reader);
 
+                                        int initialDepth = reader.Depth;
                                         if (reader.TokenType != JsonToken.StartArray)
                                         {
                                             throw new InvalidDataException($"Expected '{ArgumentsPropertyName}' to be of type {JTokenType.Array}.");
@@ -231,6 +232,14 @@ private HubMessage ParseMessage(Utf8BufferTextReader textReader, IInvocationBind
                                             catch (Exception ex)
                                             {
                                                 argumentBindingException = ExceptionDispatchInfo.Capture(ex);
+
+                                                // Could be at any point in argument array JSON when an error is thrown
+                                                // Read until the end of the argument JSON array
+                                                while (reader.Depth == initialDepth && reader.TokenType == JsonToken.StartArray ||
+                                                       reader.Depth > initialDepth)
+                                                {
+                                                    JsonUtils.CheckRead(reader);
+                                                }
                                             }
                                         }
                                         break;

test/Microsoft.AspNetCore.SignalR.Common.Tests/Internal/Protocol/JsonHubProtocolTests.cs

@@ -294,6 +294,18 @@ public void DateTimeReturnValuePreservesUtcKind(string input)
             Assert.Equal(DateTimeKind.Utc, dt.Kind);
         }
 
+        [Fact]
+        public void ReadToEndOfArgumentArrayOnError()
+        {
+            var binder = new TestBinder(new[] { typeof(string) });
+            var protocol = new JsonHubProtocol();
+            var data = new ReadOnlySequence<byte>(Encoding.UTF8.GetBytes(Frame("{'type':1,'invocationId':'42','target':'foo','arguments':[[],{'target':'foo2'}]}")));
+            protocol.TryParseMessage(ref data, binder, out var message);
+            var bindingFailure = Assert.IsType<InvocationBindingFailureMessage>(message);
+
+            Assert.Equal("foo", bindingFailure.Target);
+        }
+
         private static string Frame(string input)
         {
             var data = Encoding.UTF8.GetBytes(input);