Keep connection alive when peer doesn't support pubsub (#754)

libp2p/protocols/pubsub/pubsub.nim

@@ -292,19 +292,11 @@ proc getOrCreatePeer*(
   proc getConn(): Future[Connection] {.async.} =
     return await p.switch.dial(peerId, protos)
 
-  proc dropConn(peer: PubSubPeer) =
-    proc dropConnAsync(peer: PubSubPeer) {.async.} =
-      try:
-        await p.switch.disconnect(peer.peerId)
-      except CatchableError as exc: # never cancelled
-        trace "Failed to close connection", peer, error = exc.name, msg = exc.msg
-    asyncSpawn dropConnAsync(peer)
-
   proc onEvent(peer: PubSubPeer, event: PubSubPeerEvent) {.gcsafe.} =
     p.onPubSubPeerEvent(peer, event)
 
   # create new pubsub peer
-  let pubSubPeer = PubSubPeer.new(peerId, getConn, dropConn, onEvent, protos[0], p.maxMessageSize)
+  let pubSubPeer = PubSubPeer.new(peerId, getConn, onEvent, protos[0], p.maxMessageSize)
   debug "created new pubsub peer", peerId
 
   p.peers[peerId] = pubSubPeer

libp2p/protocols/pubsub/pubsubpeer.nim

@@ -51,7 +51,6 @@ type
 
   PubSubPeer* = ref object of RootObj
     getConn*: GetConn                   # callback to establish a new send connection
-    dropConn*: DropConn                 # Function pointer to use to drop connections
     onEvent*: OnEvent                   # Connectivity updates for peer
     codec*: string                      # the protocol that this peer joined from
     sendConn*: Connection               # cached send connection
@@ -206,9 +205,6 @@ proc connectImpl(p: PubSubPeer) {.async.} =
       await connectOnce(p)
   except CatchableError as exc: # never cancelled
     debug "Could not establish send connection", msg = exc.msg
-  finally:
-    # drop the connection, else we end up with ghost peers
-    if p.dropConn != nil: p.dropConn(p)
 
 proc connect*(p: PubSubPeer) =
   asyncSpawn connectImpl(p)
@@ -286,14 +282,12 @@ proc new*(
   T: typedesc[PubSubPeer],
   peerId: PeerId,
   getConn: GetConn,
-  dropConn: DropConn,
   onEvent: OnEvent,
   codec: string,
   maxMessageSize: int): T =
 
   T(
     getConn: getConn,
-    dropConn: dropConn,
     onEvent: onEvent,
     codec: codec,
     peerId: peerId,

tests/pubsub/testgossipinternal.nim

@@ -22,10 +22,7 @@ proc getPubSubPeer(p: TestGossipSub, peerId: PeerId): PubSubPeer =
   proc getConn(): Future[Connection] =
     p.switch.dial(peerId, GossipSubCodec)
 
-  proc dropConn(peer: PubSubPeer) =
+  let pubSubPeer = PubSubPeer.new(peerId, getConn, nil, GossipSubCodec, 1024 * 1024)
-    discard # we don't care about it here yet
-
-  let pubSubPeer = PubSubPeer.new(peerId, getConn, dropConn, nil, GossipSubCodec, 1024 * 1024)
   debug "created new pubsub peer", peerId
 
   p.peers[peerId] = pubSubPeer