fix(proto): handle V3 member metadata and empty owned partitions

Signed-off-by: Dominic Evans <dominic.evans@uk.ibm.com>

consumer_group_members.go

@@ -9,6 +9,8 @@ type ConsumerGroupMemberMetadata struct {
 	Topics          []string
 	UserData        []byte
 	OwnedPartitions []*OwnedPartition
+	GenerationID    int32
+	RackID          *string
 }
 
 func (m *ConsumerGroupMemberMetadata) encode(pe packetEncoder) error {
@@ -22,6 +24,27 @@ func (m *ConsumerGroupMemberMetadata) encode(pe packetEncoder) error {
 		return err
 	}
 
+	if m.Version >= 1 {
+		if err := pe.putArrayLength(len(m.OwnedPartitions)); err != nil {
+			return err
+		}
+		for _, op := range m.OwnedPartitions {
+			if err := op.encode(pe); err != nil {
+				return err
+			}
+		}
+	}
+
+	if m.Version >= 2 {
+		pe.putInt32(m.GenerationID)
+	}
+
+	if m.Version >= 3 {
+		if err := pe.putNullableString(m.RackID); err != nil {
+			return err
+		}
+	}
+
 	return nil
 }
 
@@ -48,18 +71,29 @@ func (m *ConsumerGroupMemberMetadata) decode(pd packetDecoder) (err error) {
 			}
 			return err
 		}
-		if n == 0 {
-			return nil
-		}
-		m.OwnedPartitions = make([]*OwnedPartition, n)
-		for i := 0; i < n; i++ {
-			m.OwnedPartitions[i] = &OwnedPartition{}
-			if err := m.OwnedPartitions[i].decode(pd); err != nil {
-				return err
+		if n > 0 {
+			m.OwnedPartitions = make([]*OwnedPartition, n)
+			for i := 0; i < n; i++ {
+				m.OwnedPartitions[i] = &OwnedPartition{}
+				if err := m.OwnedPartitions[i].decode(pd); err != nil {
+					return err
+				}
 			}
 		}
 	}
 
+	if m.Version >= 2 {
+		if m.GenerationID, err = pd.getInt32(); err != nil {
+			return err
+		}
+	}
+
+	if m.Version >= 3 {
+		if m.RackID, err = pd.getNullableString(); err != nil {
+			return err
+		}
+	}
+
 	return nil
 }
 
@@ -68,6 +102,16 @@ type OwnedPartition struct {
 	Partitions []int32
 }
 
+func (m *OwnedPartition) encode(pe packetEncoder) error {
+	if err := pe.putString(m.Topic); err != nil {
+		return err
+	}
+	if err := pe.putInt32Array(m.Partitions); err != nil {
+		return err
+	}
+	return nil
+}
+
 func (m *OwnedPartition) decode(pd packetDecoder) (err error) {
 	if m.Topic, err = pd.getString(); err != nil {
 		return err

consumer_group_members_test.go

@@ -42,6 +42,16 @@ var (
 		0, 0, 0, 3, 0x01, 0x02, 0x03, // Userdata
 		0, 0, 0, 0, // OwnedPartitions KIP-429
 	}
+
+	groupMemberMetadataV3NilOwned = []byte{
+		0, 3, // Version
+		0, 0, 0, 1, // Topic array length
+		0, 3, 'o', 'n', 'e', // Topic one
+		0, 0, 0, 3, 0x01, 0x02, 0x03, // Userdata
+		0, 0, 0, 0, // OwnedPartitions KIP-429
+		0, 0, 0, 64, // GenerationID
+		0, 4, 'r', 'a', 'c', 'k', // RackID
+	}
 )
 
 func TestConsumerGroupMemberMetadata(t *testing.T) {
@@ -77,6 +87,13 @@ func TestConsumerGroupMemberMetadataV1Decode(t *testing.T) {
 	}
 }
 
+func TestConsumerGroupMemberMetadataV3Decode(t *testing.T) {
+	meta := new(ConsumerGroupMemberMetadata)
+	if err := decode(groupMemberMetadataV3NilOwned, meta, nil); err != nil {
+		t.Error("Failed to decode V3 data", err)
+	}
+}
+
 func TestConsumerGroupMemberAssignment(t *testing.T) {
 	amt := &ConsumerGroupMemberAssignment{
 		Version: 0,