From dc5283e20fb2f79f017580f52172646dcb787392 Mon Sep 17 00:00:00 2001
From: Travis Bischel <travis.bischel+github@gmail.com>
Date: Mon, 10 Jul 2023 13:53:52 -0600
Subject: [PATCH] kgo: re-fix #493, supporting other buggy clients, and add a
 test

---
 pkg/kgo/group_balancer.go      |  2 +-
 pkg/kgo/group_balancer_test.go | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/pkg/kgo/group_balancer.go b/pkg/kgo/group_balancer.go
index 87a3a248..e83758cb 100644
--- a/pkg/kgo/group_balancer.go
+++ b/pkg/kgo/group_balancer.go
@@ -216,7 +216,7 @@ func NewConsumerBalancer(balance ConsumerBalancerBalance, members []kmsg.JoinGro
 			// workaround. See #493.
 			if bytes.HasPrefix(memberMeta, []byte{0, 1}) {
 				memberMeta[0] = 0
-				memberMeta[0] = 0
+				memberMeta[1] = 0
 				if err = meta.ReadFrom(memberMeta); err != nil {
 					return nil, fmt.Errorf("unable to read member metadata: %v", err)
 				}
diff --git a/pkg/kgo/group_balancer_test.go b/pkg/kgo/group_balancer_test.go
index 3209551f..a49f82d4 100644
--- a/pkg/kgo/group_balancer_test.go
+++ b/pkg/kgo/group_balancer_test.go
@@ -98,3 +98,18 @@ func Test_stickyAdjustCooperative(t *testing.T) {
 		t.Errorf("got plan != exp\ngot: %#v\nexp: %#v\n", inPlan, expPlan)
 	}
 }
+
+func TestNewConsumerBalancerIssue493(t *testing.T) {
+	m := kmsg.NewConsumerMemberMetadata()
+	m.Version = 0
+	m.Topics = []string{"foo"}
+	protoMeta := m.AppendTo(nil)
+	protoMeta[1] = 1
+	member := kmsg.NewJoinGroupResponseMember()
+	member.MemberID = "test"
+	member.ProtocolMetadata = protoMeta
+	_, err := NewConsumerBalancer(nil, []kmsg.JoinGroupResponseMember{member})
+	if err != nil {
+		t.Errorf("got unexpected error: %v", err)
+	}
+}