lib/rubocop/cop/lint/empty_block.rb
# frozen_string_literal: true
module RuboCop
module Cop
module Lint
# Checks for blocks without a body.
# Such empty blocks are typically an oversight or we should provide a comment
# to clarify what we're aiming for.
#
# Empty lambdas and procs are ignored by default.
#
# NOTE: For backwards compatibility, the configuration that allows/disallows
# empty lambdas and procs is called `AllowEmptyLambdas`, even though it also
# applies to procs.
#
# @example
# # bad
# items.each { |item| }
#
# # good
# items.each { |item| puts item }
#
# @example AllowComments: true (default)
# # good
# items.each do |item|
# # TODO: implement later (inner comment)
# end
#
# items.each { |item| } # TODO: implement later (inline comment)
#
# @example AllowComments: false
# # bad
# items.each do |item|
# # TODO: implement later (inner comment)
# end
#
# items.each { |item| } # TODO: implement later (inline comment)
#
# @example AllowEmptyLambdas: true (default)
# # good
# allow(subject).to receive(:callable).and_return(-> {})
#
# placeholder = lambda do
# end
# (callable || placeholder).call
#
# proc { }
#
# Proc.new { }
#
# @example AllowEmptyLambdas: false
# # bad
# allow(subject).to receive(:callable).and_return(-> {})
#
# placeholder = lambda do
# end
# (callable || placeholder).call
#
# proc { }
#
# Proc.new { }
#
class EmptyBlock < Base
MSG = 'Empty block detected.'
def on_block(node) # rubocop:disable InternalAffairs/NumblockHandler
return if node.body
return if allow_empty_lambdas? && node.lambda_or_proc?
return if cop_config['AllowComments'] && allow_comment?(node)
add_offense(node)
end
private
def allow_comment?(node)
return false unless processed_source.contains_comment?(node.source_range)
line_comment = processed_source.comment_at_line(node.source_range.line)
!line_comment || !comment_disables_cop?(line_comment.source)
end
def allow_empty_lambdas?
cop_config['AllowEmptyLambdas']
end
def comment_disables_cop?(comment)
regexp_pattern = "# rubocop : (disable|todo) ([^,],)* (all|#{cop_name})"
Regexp.new(regexp_pattern.gsub(' ', '\s*')).match?(comment)
end
end
end
end
end