Include the two QUIC version sets in connection close details.

net/quic/core/quic_connection.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/core/quic_connection.h"
 
 #include <string.h>
 #include <sys/types.h>
 
 #include <algorithm>
@@ skipping 530 matching lines @@
         "Server already supports client's version and should have accepted the "
         "connection.";
     DLOG(WARNING) << error_details;
     TearDownLocalConnectionState(QUIC_INVALID_VERSION_NEGOTIATION_PACKET,
                                  error_details,
                                  ConnectionCloseSource::FROM_SELF);
     return;
   }
 
   if (!SelectMutualVersion(packet.versions)) {
-    CloseConnection(QUIC_INVALID_VERSION, "No common version found.",
-                    ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET);
+    CloseConnection(
+        QUIC_INVALID_VERSION,
+        "No common version found. Supported versions: {" +
+            QuicVersionVectorToString(framer_.supported_versions()) +
+            "}, peer supported versions: {" +
+            QuicVersionVectorToString(packet.versions) + "}",
+        ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET);
     return;
   }
 
   DVLOG(1) << ENDPOINT
            << "Negotiated version: " << QuicVersionToString(version());
   received_packet_manager_.SetVersion(version());
   server_supported_versions_ = packet.versions;
   version_negotiation_state_ = NEGOTIATION_IN_PROGRESS;
   RetransmitUnackedPackets(ALL_UNACKED_RETRANSMISSION);
 }
@@ skipping 1991 matching lines @@
 
 void QuicConnection::CheckIfApplicationLimited() {
   if (queued_packets_.empty() &&
       !sent_packet_manager_->HasPendingRetransmissions() &&
       !visitor_->WillingAndAbleToWrite()) {
     sent_packet_manager_->OnApplicationLimited();
   }
 }
 
 }  // namespace net