From 34f98a891343858e2dca1236db7fcf06f8d9fc31 Mon Sep 17 00:00:00 2001
From: EMayej Bee <EMayej@gmail.com>
Date: Thu, 18 Jan 2018 10:27:42 +0800
Subject: [PATCH] fix: WatchConfig leads to panic if OnConfigChange is not
 called

---
 viper.go | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/viper.go b/viper.go
index ad8a037..3b6b681 100644
--- a/viper.go
+++ b/viper.go
@@ -289,7 +289,10 @@ func (v *Viper) WatchConfig() {
 							if err != nil {
 								log.Println("error:", err)
 							}
-							v.onConfigChange(event)
+
+							if v.onConfigChange != nil {
+								v.onConfigChange(event)
+							}
 						}
 					}
 				case err := <-watcher.Errors: