Fix broadcastSegment Contains and its usage

OffchainLabs · Dec 21, 2023 · 11d76f6 · 11d76f6
1 parent ae54e08
commit 11d76f6
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Showing 2 changed files with 5 additions and 2 deletions.
diff --git a/broadcaster/backlog/backlog.go b/broadcaster/backlog/backlog.go
@@ -379,7 +379,7 @@ func (s *backlogSegment) Contains(i uint64) bool {
 	s.messagesLock.RLock()
 	defer s.messagesLock.RUnlock()
 	start := s.start()
-	if i < start || i > s.end() {
+	if i < start || i > s.end() || len(s.messages) == 0 {
 		return false
 	}
 

diff --git a/wsbroadcastserver/clientconnection.go b/wsbroadcastserver/clientconnection.go
@@ -134,7 +134,10 @@ func (cc *ClientConnection) writeBacklog(ctx context.Context, segment backlog.Ba
 		msgs := prevSegment.Messages()
 		if prevSegment.Contains(uint64(cc.requestedSeqNum)) {
 			requestedIdx := int(cc.requestedSeqNum) - int(prevSegment.Start())
-			msgs = msgs[requestedIdx:]
+			// This might be false if messages were added after we fetched the segment's messages
+			if len(msgs) > requestedIdx {
+				msgs = msgs[requestedIdx:]
+			}
 		}
 		bm := &m.BroadcastMessage{
 			Version:  m.V1,