class RuboCop::Formatter::FileListFormatter

/some/other/file
/some/file
Here’s the format:
separated by newlines. The output is machine-parsable.
This formatter displays just a list of the files with offenses in them,

def file_finished(file, offenses) 

def file_finished(file, offenses)
  return if offenses.empty?
  output.printf("%<path>s\n", path: file)
end