From bc249730aac7a6c89dd1bfb5a2f2436ddba496d3 Mon Sep 17 00:00:00 2001
From: Matt Joiner <anacrolix@gmail.com>
Date: Wed, 10 Apr 2019 18:27:54 +1000
Subject: [PATCH] Fix segfault on nil conntrack.EntryHandle instance when
 dialing

Fixes https://github.com/anacrolix/torrent/issues/314. Comments were added to the the conntrack package master, but have no functional change required here.
---
 client.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/client.go b/client.go
index f8d70372b9..2d2a3fa7ea 100644
--- a/client.go
+++ b/client.go
@@ -521,8 +521,13 @@ func (cl *Client) dialFirst(ctx context.Context, addr string) dialResult {
 						"dial torrent client",
 						0,
 					)
+					// Try to avoid committing to a dial if the context is complete as it's
+					// difficult to determine which dial errors allow us to forget the connection
+					// tracking entry handle.
 					if ctx.Err() != nil {
-						cte.Forget()
+						if cte != nil {
+							cte.Forget()
+						}
 						resCh <- dialResult{}
 						return
 					}