[IMPROVED] Handle error and reset ordered consumer in Messages() (#1646)

Signed-off-by: Piotr Piotrowski <piotr@synadia.com>

jetstream/ordered.go

@@ -18,6 +18,7 @@ import (
 	"errors"
 	"fmt"
 	"strconv"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -291,15 +292,24 @@ func (s *orderedSubscription) Next() (Msg, error) {
 			}
 			continue
 		}
+
 		meta, err := msg.Metadata()
 		if err != nil {
-			s.consumer.errHandler(s.consumer.serial)(sub, err)
-			continue
+			return nil, err
 		}
 		serial := serialNumberFromConsumer(meta.Consumer)
+		if serial != s.consumer.serial {
+			continue
+		}
 		dseq := meta.Sequence.Consumer
 		if dseq != s.consumer.cursor.deliverSeq+1 {
-			s.consumer.errHandler(serial)(sub, errOrderedSequenceMismatch)
+			if err := s.consumer.reset(); err != nil {
+				return nil, err
+			}
+			_, err := s.consumer.currentConsumer.Messages(s.opts...)
+			if err != nil {
+				return nil, err
+			}
 			continue
 		}
 		s.consumer.cursor.deliverSeq = dseq
@@ -448,7 +458,11 @@ func serialNumberFromConsumer(name string) int {
 	if len(name) == 0 {
 		return 0
 	}
-	serial, err := strconv.Atoi(name[len(name)-1:])
+	parts := strings.Split(name, "_")
+	if len(parts) < 2 {
+		return 0
+	}
+	serial, err := strconv.Atoi(parts[len(parts)-1])
 	if err != nil {
 		return 0
 	}