From a1e657ce53ba59e6e4076edaa2c68d398e7f7e4f Mon Sep 17 00:00:00 2001
From: Sergey Matyukevich <s.matyukevich@gmail.com>
Date: Wed, 15 Mar 2023 11:19:01 -0600
Subject: [PATCH] client: log last error on subchannel connectivity change
 (#6109)

---
 clientconn.go | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/clientconn.go b/clientconn.go
index b50c698a0..b9cc05507 100644
--- a/clientconn.go
+++ b/clientconn.go
@@ -1113,7 +1113,11 @@ func (ac *addrConn) updateConnectivityState(s connectivity.State, lastErr error)
 		return
 	}
 	ac.state = s
-	channelz.Infof(logger, ac.channelzID, "Subchannel Connectivity change to %v", s)
+	if lastErr == nil {
+		channelz.Infof(logger, ac.channelzID, "Subchannel Connectivity change to %v", s)
+	} else {
+		channelz.Infof(logger, ac.channelzID, "Subchannel Connectivity change to %v, last error: %s", s, lastErr)
+	}
 	ac.cc.handleSubConnStateChange(ac.acbw, s, lastErr)
 }