From 65e8f0b086b8f3274b618aad1738b3b7758c37f0 Mon Sep 17 00:00:00 2001
From: Christian Mohrbacher <christian.mohrbacher@itwm.fraunhofer.de>
Date: Fri, 13 Jul 2018 15:55:31 +0200
Subject: [PATCH] if config type is already set, ignore file extension and use
 the saved config type

e.g. if viper.SetConfigType("yaml") was previously called, yaml will be used as
config format, even if the file is called XXX.conf, instead of XXXX.yaml
---
 viper.go | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/viper.go b/viper.go
index 907a102..db2d6d6 100644
--- a/viper.go
+++ b/viper.go
@@ -1245,7 +1245,14 @@ func (v *Viper) writeConfig(filename string, force bool) error {
 	if len(ext) <= 1 {
 		return fmt.Errorf("Filename: %s requires valid extension.", filename)
 	}
-	configType := ext[1:]
+
+	var configType string
+	if v.configType == "" {
+		configType = ext[1:]
+	} else {
+		configType = v.configType
+	}
+
 	if !stringInSlice(configType, SupportedExts) {
 		return UnsupportedConfigError(configType)
 	}