Detect duplicate comments

comments.rb

require 'parser/current'
require 'pathname'

require 'concord'

class Comment
  include Equalizer.new(:text)

  def initialize(path, comment)
    @path    = path
    @comment = comment
  end

  def text
    comment.text
  end

  def <=>(other)
    text <=> other.text
  end

  attr_reader :path, :comment
end

comments =
  Pathname
    .glob('lib/**/*.rb')
    .flat_map do |path|
      Parser::CurrentRuby.parse_with_comments(path.read).last.map do |comment|
        Comment.new(path, comment)
      end
    end

@seen = Set.new

ignores = [
  '#',
  '#   otherwise',
  /\A# [A-Z]\w+\z/,
  /\A# rubocop:disable \w+/,
  /\A# @\w/,
  /\A# @\w/,
  /\A# @\w/,
  /\A# @\w/,
]

duplicates = []

comments
  .reject do |comment|
    ignores.any? { |ignore| ignore === comment.text }
  end
  .sort
  .group_by { |comment| comment.text }
  .reject { |_, comments| comments.one? }
  .sort_by { |_, comments| comments.size }
  .each do |text, comments|
    next if comments.one?
    warn text

    comments.each do |comment|
      warn "  #{comment.path}:#{comment.comment.loc.line}"
    end
  end