Watch the entire config dir for changes

Then checking the file name in the event handler. This seems to be the only robust way
of handling changes from a single file on multiple platforms and editors.

See #142

viper.go

@@ -237,11 +237,17 @@ func (v *Viper) WatchConfig() {
 		}
 		defer watcher.Close()
 
+		// we have to watch the entire directory to pick up renames/atomic saves in a cross-platform way
+		configFile := filepath.Clean(v.getConfigFile())
+		configDir, _ := filepath.Split(configFile)
+
 		done := make(chan bool)
 		go func() {
 			for {
 				select {
 				case event := <-watcher.Events:
+					// we only care about the config file
+					if filepath.Clean(event.Name) == configFile {
 						if event.Op&fsnotify.Write == fsnotify.Write || event.Op&fsnotify.Create == fsnotify.Create {
 							err := v.ReadInConfig()
 							if err != nil {
@@ -249,13 +255,14 @@ func (v *Viper) WatchConfig() {
 							}
 							v.onConfigChange(event)
 						}
+					}
 				case err := <-watcher.Errors:
 					log.Println("error:", err)
 				}
 			}
 		}()
 
-		watcher.Add(v.getConfigFile())
+		watcher.Add(configDir)
 		<-done
 	}()
 }