revid: checking that we have more than 0 destinations before we write to the ring buffer

revid/revid.go

@@ -142,6 +142,10 @@ func (p *packer) Write(frame []byte) (int, error) {
 		return len(frame), nil
 	}
 
+	if len(p.owner.destination) == 0 {
+		panic("must have at least 1 destination")
+	}
+
 	n, err := p.owner.buffer.Write(frame)
 	if err != nil {
 		if err == ring.ErrDropped {