Immediately forget swarms for which we've never seen peers.

1 files changed, 9 insertions, 9 deletions

diff --git a/src/Network/BitTorrent/DHT/ContactInfo.hs b/src/Network/BitTorrent/DHT/ContactInfo.hs
index 117325fc..ea3b96f0 100644
--- a/src/Network/BitTorrent/DHT/ContactInfo.hs
+++ b/src/Network/BitTorrent/DHT/ContactInfo.hs
@@ -202,15 +202,15 @@ batchSize = 64
 
 -- | Used in 'get_peers' DHT queries.
 freshPeers :: Ord a => InfoHash -> Timestamp -> PeerStore a -> ([PeerAddr a], PeerStore a)
-freshPeers ih tm (PeerStore m) = (ps, PeerStore m')
- where
-    swarm = fromMaybe (SwarmData PSQ.empty Nothing) $ HM.lookup ih m
-    ps0 = take batchSize $ unfoldr (incomp minView) (peers swarm)
-    peers' = case reverse ps0 of
-                (_,psq):_ -> psq
-                _         -> peers swarm
-    ps = L.map (key . fst) ps0
-    m' = HM.insert ih swarm { peers = L.foldl' (\q p -> PSQ.insert p tm q) peers' ps } m
+freshPeers ih tm (PeerStore m) = fromMaybe ([],PeerStore m) $ do
+    swarm <- HM.lookup ih m
+    let ps0 = take batchSize $ unfoldr (incomp minView) (peers swarm)
+        peers' = case reverse ps0 of
+                    (_,psq):_ -> psq
+                    _         -> peers swarm
+        ps = L.map (key . fst) ps0
+        m' = HM.insert ih swarm { peers = L.foldl' (\q p -> PSQ.insert p tm q) peers' ps } m
+    return (ps,PeerStore m')
 
 incomp :: (x -> Maybe (r,x)) -> x -> Maybe ((r,x),x)
 incomp f x = do