added comment to windows filePath check

altsrc/yaml_file_loader.go

@@ -81,6 +81,7 @@ func loadDataFrom(filePath string) ([]byte, error) {
 		}
 		return ioutil.ReadFile(filePath)
 	} else if runtime.GOOS == "windows" && strings.Contains(u.String(), "\\") {
+		// on Windows systems u.Path is always empty, so we need to check the string directly.
 		if _, notFoundFileErr := os.Stat(filePath); notFoundFileErr != nil {
 			return nil, fmt.Errorf("Cannot read from file: '%s' because it does not exist.", filePath)
 		}