From d2d162ece35dcf942978f0a481ef2ef3915c2e5d Mon Sep 17 00:00:00 2001
From: Juliusz Stasiewicz <juliusz.stasiewicz@scylladb.com>
Date: Mon, 5 Oct 2020 13:35:10 +0200
Subject: [PATCH] transport: Notify `system.clients` about "protocol_version"

---
 transport/server.cc | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/transport/server.cc b/transport/server.cc
index 9028b2968f..fac681a0c8 100644
--- a/transport/server.cc
+++ b/transport/server.cc
@@ -371,6 +371,16 @@ cql_server::connection::read_frame() {
                 _version = current_version;
                 throw exceptions::protocol_exception(format("Invalid or unsupported protocol version: {:d}", client_version));
             }
+
+          auto client_state_notification_f = std::apply(notify_client_change<changed_column::protocol_version>{},
+                  std::tuple_cat(make_client_key(_client_state), std::make_tuple(_version)));
+
+          return client_state_notification_f.then_wrapped([this] (future<> f) {
+            try {
+                f.get();
+            } catch (...) {
+                clogger.info("exception while setting protocol_version in `system.clients`: {}", std::current_exception());
+            }
             return _read_buf.read_exactly(frame_size() - 1).then([this] (temporary_buffer<char> tail) {
                 temporary_buffer<char> full(frame_size());
                 full.get_write()[0] = _version;
@@ -385,6 +395,7 @@ cql_server::connection::read_frame() {
                 }
                 return make_ready_future<ret_type>(frame);
             });
+          });
         });
     } else {
         // Not the first frame, so we know the size.