diff

# File railties/lib/rails/commands/credentials/credentials_command.rb, line 46
      def diff(content_path = nil)
        if @content_path = content_path
          self.environment = extract_environment_from_path(content_path)
          load_environment_config!

          say credentials.read.presence || credentials.content_path.read
        else
          disenroll_project_from_credentials_diffing if options[:disenroll]
          enroll_project_in_credentials_diffing if options[:enroll]
        end
      rescue ActiveSupport::MessageEncryptor::InvalidMessage
        say credentials.content_path.read
      end