From 98e3faa0ad7ec12988c70ab2ab4926c470349f97 Mon Sep 17 00:00:00 2001
From: Nathan Trujillo <nathan.trujillo@sony.com>
Date: Tue, 6 Nov 2018 14:34:04 -0800
Subject: [PATCH] implement os.ExpandEnv, and augment test to meet both forms
 it supports

---
 util.go       | 6 ++----
 viper_test.go | 3 +++
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/util.go b/util.go
index 6f2d771..4c1b0da 100644
--- a/util.go
+++ b/util.go
@@ -222,14 +222,12 @@ func deepSearch(m map[string]interface{}, path []string) map[string]interface{}
 }
 // We look up a environmental variable if it looks like '${HOME}'
 func lookupEnvByValue(s string) string {
-	match, err := regexp.MatchString("\\${[A-Za-z_-]+}", s)
+	match, err := regexp.MatchString("(\\$[A-Za-z_-]+|\\${[A-Za-z_-]+})", s)
 	if (err != nil) {
 		fmt.Println(match, err)
 	}
 	if (match) {	
-		re := regexp.MustCompile("(\\$|{|}|)")
-		clean := re.ReplaceAllString(s, "")
-		env := os.Getenv(clean)
+		env := os.ExpandEnv(s)
 		if ( env != "" ) {
 			return  env
 		}
diff --git a/viper_test.go b/viper_test.go
index b55db98..3e2e3d3 100644
--- a/viper_test.go
+++ b/viper_test.go
@@ -51,6 +51,7 @@ beard: true
 var yamlExampleWithEnv = []byte(`
 home: '${HOME_STUFF}'
 undefined: '${UNDEFINED}'
+theclown: ${HOME_STUFF}
 `)
 
 var yamlExampleWithExtras = []byte(`Existing: true
@@ -452,6 +453,8 @@ func TestGetStringEnv(t *testing.T) {
 	value := v.GetStringEnv("home")
 	// defined env variables are interpolated
 	assert.Equal(t, ".", value)
+	value = v.GetStringEnv("theclown")
+	assert.Equal(t, ".", value)
 	// undefined env variables are untouched
 	undefined_value := v.GetStringEnv("undefined")
 	assert.Equal(t, "${UNDEFINED}", undefined_value)