46 lines
1.5 KiB
Ruby
46 lines
1.5 KiB
Ruby
|
# frozen_string_literal: true
|
||
|
|
|
||
|
|
module RuboCop
|
||
|
|
module Cop
|
||
|
|
module Gitlab
|
||
|
|
# This cop looks for delegations to predicate methods with `allow_nil: true` option.
|
||
|
|
# This construct results in three possible results: true, false and nil.
|
||
|
|
# In other words, it does not preserve the strict Boolean nature of predicate method return value.
|
||
|
|
# This cop suggests creating a method to handle `nil` delegator and ensure only Boolean type is returned.
|
||
|
|
#
|
||
|
|
# @example
|
||
|
|
# # bad
|
||
|
|
# delegate :is_foo?, to: :bar, allow_nil: true
|
||
|
|
#
|
||
|
|
# # good
|
||
|
|
# def is_foo?
|
||
|
|
# return false unless bar
|
||
|
|
# bar.is_foo?
|
||
|
|
# end
|
||
|
|
#
|
||
|
|
# def is_foo?
|
||
|
|
# !!bar&.is_foo?
|
||
|
|
# end
|
||
|
|
class DelegatePredicateMethods < RuboCop::Cop::Cop
|
||
|
|
MSG = "Using `delegate` with `allow_nil` on the following predicate methods is discouraged: %s."
|
||
|
|
RESTRICT_ON_SEND = %i[delegate].freeze
|
||
|
|
def_node_matcher :predicate_allow_nil_option, <<~PATTERN
|
||
|
|
(send nil? :delegate
|
||
|
|
(sym $_)*
|
||
|
|
(hash <$(pair (sym :allow_nil) true) ...>)
|
||
|
|
)
|
||
|
|
PATTERN
|
||
|
|
|
||
|
|
def on_send(node)
|
||
|
|
predicate_allow_nil_option(node) do |delegated_methods, _options|
|
||
|
|
offensive_methods = delegated_methods.select { |method| method.end_with?('?') }
|
||
|
|
next if offensive_methods.empty?
|
||
|
|
|
||
|
|
add_offense(node, message: format(MSG, offensive_methods.join(', ')))
|
||
|
|
end
|
||
|
|
end
|
||
|
|
end
|
||
|
|
end
|
||
|
|
end
|
||
|
|
end
|