Fix panic caused by adding disabled udp trackers

diff --git a/torrent.go b/torrent.go
index 0a8cfe4b6a6a7f15a94a6c1b3670676d27497ed2..927b25fdbdce28d07cc1ebab9992ed89c1393136 100644 (file)
--- a/torrent.go
+++ b/torrent.go
@@ -1386,6 +1386,9 @@ func (t *Torrent) startScrapingTracker(_url string) {
                go newAnnouncer.Run()
                return newAnnouncer
        }()
+       if sl == nil {
+               return
+       }
        if t.trackerAnnouncers == nil {
                t.trackerAnnouncers = make(map[string]torrentTrackerAnnouncer)
        }