kgo: re-fix #493, supporting other buggy clients, and add a test

twmb · Jul 10, 2023 · dc5283e · dc5283e
1 parent 32ac27f
commit dc5283e
Show file tree

Hide file tree

Showing 2 changed files with 16 additions and 1 deletion.
diff --git 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
@@ -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)
+	}
+}