From d90f2bb139e1c12fa276ee449cd68e8c6c5c1602 Mon Sep 17 00:00:00 2001
From: Cameron Moore <moorereason@gmail.com>
Date: Tue, 27 Dec 2016 21:49:59 -0600
Subject: [PATCH] Only save config on success in ReadInConfig

If the user creates a invalid config file while watching for config
changes, the previous, valid config is not retained.  This commit only
overwrites the running config if unmarshalling was successful.
---
 viper.go | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/viper.go b/viper.go
index 2603c78..fce13b1 100644
--- a/viper.go
+++ b/viper.go
@@ -1093,9 +1093,15 @@ func (v *Viper) ReadInConfig() error {
 		return err
 	}
 
-	v.config = make(map[string]interface{})
+	config := make(map[string]interface{})
 
-	return v.unmarshalReader(bytes.NewReader(file), v.config)
+	err = v.unmarshalReader(bytes.NewReader(file), config)
+	if err != nil {
+		return err
+	}
+
+	v.config = config
+	return nil
 }
 
 // MergeInConfig merges a new configuration with an existing config.