class Rubocop::Cop::Syntax

def inspect_file(file)
  # Starting JRuby processes would be extremely slow
  # We need to check if rbx returns nice warning messages
  return unless RUBY_ENGINE == 'ruby'
  stderr = nil
  # it's extremely important to run the syntax check in a
  # clean environment - otherwise it will be extremely slow
  if defined? Bundler
    Bundler.with_clean_env do
      _, stderr, _ = Open3.capture3("ruby -wc #{file}")
    end
  else
    _, stderr, _ = Open3.capture3("ruby -wc #{file}")
  end
  stderr.each_line do |line|
    # discard lines that are not containing relevant info
    if line =~ /.+:(\d+): (.+)/
      # Assignment to unused variables beginning with underscore
      # is reported by Ruby 1.9, but not 2.0. Make 1.9 behave
      # like 2.0.
      unless line =~ /assigned but unused variable - _\w+/
        line_no, severity, message = process_line(line)
        add_offence(severity, line_no, message)
      end
    end
  end
end

def process_line(line)
  line_no, message = line.match(/.+:(\d+): (.+)/).captures
  if message.start_with?('warning: ')
    [line_no.to_i, :warning, message.sub(/warning: /, '').capitalize]
  else
    [line_no.to_i, :error, message.capitalize]
  end
end