class RuboCop::Cop::Style::MethodLength

The maximum allowed length is configurable.
Comment lines can optionally be ignored.
This cop checks if the length a method exceeds some maximum value.

def code_length(node) 

def code_length(node)
  lines = node.loc.expression.source.lines.to_a[1..-2] || []
  lines.reject! { |line| irrelevant_line(line) }
  lines.size
end

def message 

def message
  'Method has too many lines. [%d/%d]'
end