From 9f3ffaf6ed0ddd53b1a15c68639afb6e17dd57a5 Mon Sep 17 00:00:00 2001
From: Steven Allen <steven@stebalien.com>
Date: Fri, 14 Jun 2019 10:19:51 -0700
Subject: [PATCH] fix: rand.Intn(0) panics

---
 session/session.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/session/session.go b/session/session.go
index f10d9605..0757ab11 100644
--- a/session/session.go
+++ b/session/session.go
@@ -347,6 +347,9 @@ func (s *Session) handlePeriodicSearch(ctx context.Context) {
 }
 
 func (s *Session) randomLiveWant() cid.Cid {
+	if len(s.liveWants) == 0 {
+		return cid.Cid{}
+	}
 	i := rand.Intn(len(s.liveWants))
 	// picking a random live want
 	for k := range s.liveWants {