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

consumer_group.go

@@ -165,15 +165,15 @@ func (c *consumerGroup) Consume(ctx context.Context, topics []string, handler Co
 
 	// Refresh metadata for requested topics
 	if err := c.client.RefreshMetadata(topics...); err != nil {
-		return err
+		return fmt.Errorf("failed to resfresh topic metadata: %w", err)
 	}
 
 	// Init session
 	sess, err := c.newSession(ctx, topics, handler, c.config.Consumer.Group.Rebalance.Retry.Max)
 	if err == ErrClosedClient {
 		return ErrClosedConsumerGroup
 	} else if err != nil {
-		return err
+		return fmt.Errorf("failed to init new session: %w", err)
 	}
 
 	// loop check topic partition numbers changed
@@ -209,7 +209,7 @@ func (c *consumerGroup) newSession(ctx context.Context, topics []string, handler
 	coordinator, err := c.client.Coordinator(c.groupID)
 	if err != nil {
 		if retries <= 0 {
-			return nil, err
+			return nil, fmt.Errorf("failed to get coordinator: %w", err)
 		}
 
 		return c.retryNewSession(ctx, topics, handler, retries, true)
@@ -240,7 +240,7 @@ func (c *consumerGroup) newSession(ctx context.Context, topics []string, handler
 		if consumerGroupJoinFailed != nil {
 			consumerGroupJoinFailed.Inc(1)
 		}
-		return nil, err
+		return nil, fmt.Errorf("failed to join consumer group: %w", err)
 	}
 	if join.Err != ErrNoError {
 		if consumerGroupJoinFailed != nil {
@@ -285,7 +285,7 @@ func (c *consumerGroup) newSession(ctx context.Context, topics []string, handler
 	if join.LeaderId == join.MemberId {
 		members, err := join.GetMembers()
 		if err != nil {
-			return nil, err
+			return nil, fmt.Errorf("failed to get group members: %w", err)
 		}
 
 		plan, err = c.balance(strategy, members)

consumer_group_members.go

@@ -7,6 +7,8 @@ type ConsumerGroupMemberMetadata struct {
 	Topics          []string
 	UserData        []byte
 	OwnedPartitions []*OwnedPartition
+	GenerationID    int32
+	RackID          *string
 }
 
 func (m *ConsumerGroupMemberMetadata) encode(pe packetEncoder) error {
@@ -20,6 +22,27 @@ 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
 }
 
@@ -46,18 +69,29 @@ 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
 }
 
@@ -66,6 +100,16 @@ 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); err != nil {
+		t.Error("Failed to decode V3 data", err)
+	}
+}
+
 func TestConsumerGroupMemberAssignment(t *testing.T) {
 	amt := &ConsumerGroupMemberAssignment{
 		Version: 0,