fix: correct bugs in DescribeGroupsResponse

consumer_group_members.go

@@ -1,10 +1,12 @@
 package sarama
 
 // ConsumerGroupMemberMetadata holds the metadata for consumer group
+// https://github.com/apache/kafka/blob/trunk/clients/src/main/resources/common/message/ConsumerProtocolSubscription.json
 type ConsumerGroupMemberMetadata struct {
-	Version  int16
-	Topics   []string
-	UserData []byte
+	Version         int16
+	Topics          []string
+	UserData        []byte
+	OwnedPartitions []*OwnedPartition
 }
 
 func (m *ConsumerGroupMemberMetadata) encode(pe packetEncoder) error {
@@ -33,11 +35,50 @@ func (m *ConsumerGroupMemberMetadata) decode(pd packetDecoder) (err error) {
 	if m.UserData, err = pd.getBytes(); err != nil {
 		return
 	}
+	if m.Version >= 1 {
+		n, err := pd.getArrayLength()
+		if err != nil {
+			// permit missing data here in case of misbehaving 3rd party
+			// clients who incorrectly marked the member metadata as V1 in
+			// their JoinGroup request
+			if err == ErrInsufficientData {
+				return nil
+			}
+			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
+			}
+		}
+	}
+
+	return nil
+}
+
+type OwnedPartition struct {
+	Topic      string
+	Partitions []int32
+}
+
+func (m *OwnedPartition) decode(pd packetDecoder) (err error) {
+	if m.Topic, err = pd.getString(); err != nil {
+		return err
+	}
+	if m.Partitions, err = pd.getInt32Array(); err != nil {
+		return err
+	}
 
 	return nil
 }
 
 // ConsumerGroupMemberAssignment holds the member assignment for a consume group
+// https://github.com/apache/kafka/blob/trunk/clients/src/main/resources/common/message/ConsumerProtocolAssignment.json
 type ConsumerGroupMemberAssignment struct {
 	Version  int16
 	Topics   map[string][]int32

consumer_group_members_test.go

@@ -7,35 +7,55 @@ import (
 )
 
 var (
-	groupMemberMetadata = []byte{
-		0, 1, // Version
+	groupMemberMetadataV0 = []byte{
+		0, 0, // Version
 		0, 0, 0, 2, // Topic array length
 		0, 3, 'o', 'n', 'e', // Topic one
 		0, 3, 't', 'w', 'o', // Topic two
 		0, 0, 0, 3, 0x01, 0x02, 0x03, // Userdata
 	}
-	groupMemberAssignment = []byte{
-		0, 1, // Version
+	groupMemberAssignmentV0 = []byte{
+		0, 0, // Version
 		0, 0, 0, 1, // Topic array length
 		0, 3, 'o', 'n', 'e', // Topic one
 		0, 0, 0, 3, // Topic one, partition array length
 		0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 4, // 0, 2, 4
 		0, 0, 0, 3, 0x01, 0x02, 0x03, // Userdata
 	}
+
+	// notably it looks like the old 3rdparty bsm/sarama-cluster incorrectly
+	// set V1 in the member metadata when it sent the JoinGroup request so
+	// we need to cope with that one being too short
+	groupMemberMetadataV1Bad = []byte{
+		0, 1, // Version
+		0, 0, 0, 2, // Topic array length
+		0, 3, 'o', 'n', 'e', // Topic one
+		0, 3, 't', 'w', 'o', // Topic two
+		0, 0, 0, 3, 0x01, 0x02, 0x03, // Userdata
+	}
+
+	groupMemberMetadataV1 = []byte{
+		0, 1, // Version
+		0, 0, 0, 2, // Topic array length
+		0, 3, 'o', 'n', 'e', // Topic one
+		0, 3, 't', 'w', 'o', // Topic two
+		0, 0, 0, 3, 0x01, 0x02, 0x03, // Userdata
+		0, 0, 0, 0, // OwnedPartitions KIP-429
+	}
 )
 
 func TestConsumerGroupMemberMetadata(t *testing.T) {
 	meta := &ConsumerGroupMemberMetadata{
-		Version:  1,
+		Version:  0,
 		Topics:   []string{"one", "two"},
 		UserData: []byte{0x01, 0x02, 0x03},
 	}
 
 	buf, err := encode(meta, nil)
 	if err != nil {
 		t.Error("Failed to encode data", err)
-	} else if !bytes.Equal(groupMemberMetadata, buf) {
-		t.Errorf("Encoded data does not match expectation\nexpected: %v\nactual: %v", groupMemberMetadata, buf)
+	} else if !bytes.Equal(groupMemberMetadataV0, buf) {
+		t.Errorf("Encoded data does not match expectation\nexpected: %v\nactual: %v", groupMemberMetadataV0, buf)
 	}
 
 	meta2 := new(ConsumerGroupMemberMetadata)
@@ -47,9 +67,19 @@ func TestConsumerGroupMemberMetadata(t *testing.T) {
 	}
 }
 
+func TestConsumerGroupMemberMetadataV1Decode(t *testing.T) {
+	meta := new(ConsumerGroupMemberMetadata)
+	if err := decode(groupMemberMetadataV1, meta); err != nil {
+		t.Error("Failed to decode V1 data", err)
+	}
+	if err := decode(groupMemberMetadataV1Bad, meta); err != nil {
+		t.Error("Failed to decode V1 'bad' data", err)
+	}
+}
+
 func TestConsumerGroupMemberAssignment(t *testing.T) {
 	amt := &ConsumerGroupMemberAssignment{
-		Version: 1,
+		Version: 0,
 		Topics: map[string][]int32{
 			"one": {0, 2, 4},
 		},
@@ -59,8 +89,8 @@ func TestConsumerGroupMemberAssignment(t *testing.T) {
 	buf, err := encode(amt, nil)
 	if err != nil {
 		t.Error("Failed to encode data", err)
-	} else if !bytes.Equal(groupMemberAssignment, buf) {
-		t.Errorf("Encoded data does not match expectation\nexpected: %v\nactual: %v", groupMemberAssignment, buf)
+	} else if !bytes.Equal(groupMemberAssignmentV0, buf) {
+		t.Errorf("Encoded data does not match expectation\nexpected: %v\nactual: %v", groupMemberAssignmentV0, buf)
 	}
 
 	amt2 := new(ConsumerGroupMemberAssignment)

describe_groups_response.go

@@ -179,12 +179,18 @@ func (gmd *GroupMemberDescription) decode(pd packetDecoder) (err error) {
 }
 
 func (gmd *GroupMemberDescription) GetMemberAssignment() (*ConsumerGroupMemberAssignment, error) {
+	if len(gmd.MemberAssignment) == 0 {
+		return nil, nil
+	}
 	assignment := new(ConsumerGroupMemberAssignment)
 	err := decode(gmd.MemberAssignment, assignment)
 	return assignment, err
 }
 
 func (gmd *GroupMemberDescription) GetMemberMetadata() (*ConsumerGroupMemberMetadata, error) {
+	if len(gmd.MemberMetadata) == 0 {
+		return nil, nil
+	}
 	metadata := new(ConsumerGroupMemberMetadata)
 	err := decode(gmd.MemberMetadata, metadata)
 	return metadata, err