redundant_receiver_in_with_options.rb

# frozen_string_literal: true

module RuboCop
  module Cop
    module Rails
      # This cop checks for redundant receiver in `with_options`.
      # Receiver is implicit from Rails 4.2 or higher.
      #
      # @example
      #   # bad
      #   class Account < ApplicationRecord
      #     with_options dependent: :destroy do |assoc|
      #       assoc.has_many :customers
      #       assoc.has_many :products
      #       assoc.has_many :invoices
      #       assoc.has_many :expenses
      #     end
      #   end
      #
      #   # good
      #   class Account < ApplicationRecord
      #     with_options dependent: :destroy do
      #       has_many :customers
      #       has_many :products
      #       has_many :invoices
      #       has_many :expenses
      #     end
      #   end
      #
      # @example
      #   # bad
      #   with_options options: false do |merger|
      #     merger.invoke(merger.something)
      #   end
      #
      #   # good
      #   with_options options: false do
      #     invoke(something)
      #   end
      #
      #   # good
      #   client = Client.new
      #   with_options options: false do |merger|
      #     client.invoke(merger.something, something)
      #   end
      #
      #   # ok
      #   # When `with_options` includes a block, all scoping scenarios
      #   # cannot be evaluated. Thus, it is ok to include the explicit
      #   # receiver.
      #   with_options options: false do |merger|
      #     merger.invoke
      #     with_another_method do |another_receiver|
      #       merger.invoke(another_receiver)
      #     end
      #   end
      class RedundantReceiverInWithOptions < Cop
        extend TargetRailsVersion
        include RangeHelp

        minimum_target_rails_version 4.2

        MSG = 'Redundant receiver in `with_options`.'

        def_node_matcher :with_options?, <<-PATTERN
          (block
            (send nil? :with_options
              (...))
            (args
              $_arg)
            $_body)
        PATTERN

        def_node_search :all_block_nodes_in, <<-PATTERN
          (block ...)
        PATTERN

        def_node_search :all_send_nodes_in, <<-PATTERN
          (send ...)
        PATTERN

        def on_block(node)
          with_options?(node) do |arg, body|
            return if body.nil?
            return unless all_block_nodes_in(body).count.zero?

            send_nodes = all_send_nodes_in(body)

            if send_nodes.all? { |n| same_value?(arg, n.receiver) }
              send_nodes.each do |send_node|
                receiver = send_node.receiver
                add_offense(send_node, location: receiver.source_range)
              end
            end
          end
        end

        def autocorrect(node)
          lambda do |corrector|
            corrector.remove(node.receiver.source_range)
            corrector.remove(node.loc.dot)
            corrector.remove(block_argument_range(node))
          end
        end

        private

        def block_argument_range(node)
          block_node = node.each_ancestor(:block).first
          block_argument = block_node.children[1].source_range

          range_between(
            search_begin_pos_of_space_before_block_argument(
              block_argument.begin_pos
            ),
            block_argument.end_pos
          )
        end

        def search_begin_pos_of_space_before_block_argument(begin_pos)
          position = begin_pos - 1

          if processed_source.raw_source[position] == ' '
            search_begin_pos_of_space_before_block_argument(position)
          else
            begin_pos
          end
        end

        def same_value?(arg_node, recv_node)
          recv_node && recv_node.children[0] == arg_node.children[0]
        end
      end
    end
  end
end