fix(consumer): use newer LeaveGroup as appropriate (#2544)

Use the correct version and format of LeaveGroup as determined by the
configured Version field.

Fixes #2486

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

consumer_group.go

@@ -141,8 +141,8 @@ func newConsumerGroup(groupID string, client Client) (ConsumerGroup, error) {
 		userData:       config.Consumer.Group.Member.UserData,
 		metricRegistry: newCleanupRegistry(config.MetricRegistry),
 	}
-	if client.Config().Consumer.Group.InstanceId != "" && config.Version.IsAtLeast(V2_3_0_0) {
-		cg.groupInstanceId = &client.Config().Consumer.Group.InstanceId
+	if config.Consumer.Group.InstanceId != "" && config.Version.IsAtLeast(V2_3_0_0) {
+		cg.groupInstanceId = &config.Consumer.Group.InstanceId
 	}
 	return cg, nil
 }
@@ -556,32 +556,43 @@ func (c *consumerGroup) leave() error {
 		return err
 	}
 
-	// KIP-345 if groupInstanceId is set, don not leave group when consumer closed.
-	// Since we do not discover ApiVersion for brokers, LeaveGroupRequest still use the old version request for now
-	if c.groupInstanceId == nil {
-		resp, err := coordinator.LeaveGroup(&LeaveGroupRequest{
-			GroupId:  c.groupID,
+	// as per KIP-345 if groupInstanceId is set, i.e. static membership is in action, then do not leave group when consumer closed, just clear memberID
+	if c.groupInstanceId != nil {
+		c.memberID = ""
+		return nil
+	}
+	req := &LeaveGroupRequest{
+		GroupId:  c.groupID,
+		MemberId: c.memberID,
+	}
+	if c.config.Version.IsAtLeast(V0_11_0_0) {
+		req.Version = 1
+	}
+	if c.config.Version.IsAtLeast(V2_0_0_0) {
+		req.Version = 2
+	}
+	if c.config.Version.IsAtLeast(V2_4_0_0) {
+		req.Version = 3
+		req.Members = append(req.Members, MemberIdentity{
 			MemberId: c.memberID,
 		})
-		if err != nil {
-			_ = coordinator.Close()
-			return err
-		}
+	}
 
-		// Unset memberID
-		c.memberID = ""
+	resp, err := coordinator.LeaveGroup(req)
+	if err != nil {
+		_ = coordinator.Close()
+		return err
+	}
 
-		// Check response
-		switch resp.Err {
-		case ErrRebalanceInProgress, ErrUnknownMemberId, ErrNoError:
-			return nil
-		default:
-			return resp.Err
-		}
-	} else {
-		c.memberID = ""
+	// clear the memberID
+	c.memberID = ""
+
+	switch resp.Err {
+	case ErrRebalanceInProgress, ErrUnknownMemberId, ErrNoError:
+		return nil
+	default:
+		return resp.Err
 	}
-	return nil
 }
 
 func (c *consumerGroup) handleError(err error, topic string, partition int32) {