From f7af2c2e5c6401216ad7f6c79400fc5dbc2c6467 Mon Sep 17 00:00:00 2001
From: Giovanni Petrantoni <giovanni@fragcolor.xyz>
Date: Mon, 6 Apr 2020 12:56:17 +0900
Subject: [PATCH] Fix possible crash in tcptransport when server is nil

---
 libp2p/transports/tcptransport.nim | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libp2p/transports/tcptransport.nim b/libp2p/transports/tcptransport.nim
index 8ee4d08dd..70d1d76c8 100644
--- a/libp2p/transports/tcptransport.nim
+++ b/libp2p/transports/tcptransport.nim
@@ -50,8 +50,10 @@ method close*(t: TcpTransport): Future[void] {.async, gcsafe.} =
   trace "stopping transport"
   await procCall Transport(t).close() # call base
 
-  t.server.stop()
-  t.server.close()
+  # server can be nil
+  if t.server != nil:
+    t.server.stop()
+    t.server.close()
   trace "transport stopped"
 
 method listen*(t: TcpTransport,