implement nested config alias -test included

viper.go

@@ -676,6 +676,14 @@ func (v *Viper) registerAlias(alias string, key string) {
 				delete(v.override, alias)
 				v.override[key] = val
 			}
+			if strings.Contains(alias, v.keyDelim) {
+				path := strings.Split(alias, v.keyDelim)
+				source := v.find(path[0])
+				if source != nil && reflect.TypeOf(source).Kind() == reflect.Map {
+					val := v.searchMap(cast.ToStringMap(source), path[1:])
+					v.config[key] = val
+				}
+			}
 			v.aliases[alias] = key
 		}
 	} else {

viper_test.go

@@ -197,6 +197,15 @@ func TestAliasInConfigFile(t *testing.T) {
 	assert.Equal(t, false, Get("beard"))
 }
 
+func TestAliasNestedInConfigFile(t *testing.T) {
+	// the config file specifies "clothing.jacket".  If we make this an alias for
+	// "clothing-jacket", we still want the old config file to work with "clothing.jacket".
+	RegisterAlias("clothing.jacket", "clothing-jacket")
+	assert.Equal(t, "leather", Get("clothing-jacket"))
+	Set("clothing-jacket", "nylon")
+	assert.Equal(t, "nylon", Get("clothing.jacket"))
+}
+
 func TestYML(t *testing.T) {
 	initYAML()
 	assert.Equal(t, "steve", Get("name"))