lib/rubocop/cop/style/redundant_double_splat_hash_braces.rb
# frozen_string_literal: true
module RuboCop
module Cop
module Style
# Checks for redundant uses of double splat hash braces.
#
# @example
#
# # bad
# do_something(**{foo: bar, baz: qux})
#
# # good
# do_something(foo: bar, baz: qux)
#
# # bad
# do_something(**{foo: bar, baz: qux}.merge(options))
#
# # good
# do_something(foo: bar, baz: qux, **options)
#
class RedundantDoubleSplatHashBraces < Base
extend AutoCorrector
MSG = 'Remove the redundant double splat and braces, use keyword arguments directly.'
MERGE_METHODS = %i[merge merge!].freeze
# rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
def on_hash(node)
return if node.pairs.empty? || node.pairs.any?(&:hash_rocket?)
return unless (parent = node.parent)
return unless parent.call_type? || parent.kwsplat_type?
return unless mergeable?(parent)
return unless (kwsplat = node.each_ancestor(:kwsplat).first)
return if !node.braces? || allowed_double_splat_receiver?(kwsplat)
add_offense(kwsplat) do |corrector|
autocorrect(corrector, node, kwsplat)
end
end
# rubocop:enable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
private
def allowed_double_splat_receiver?(kwsplat)
first_child = kwsplat.children.first
return true if first_child.block_type? || first_child.numblock_type?
return false unless first_child.call_type?
root_receiver = root_receiver(first_child)
!root_receiver&.hash_type?
end
def autocorrect(corrector, node, kwsplat)
corrector.remove(kwsplat.loc.operator)
corrector.remove(opening_brace(node))
corrector.remove(closing_brace(node))
merge_methods = select_merge_method_nodes(kwsplat)
return if merge_methods.empty?
autocorrect_merge_methods(corrector, merge_methods, kwsplat)
end
def root_receiver(node)
receiver = node.receiver
if receiver&.receiver
root_receiver(receiver)
else
receiver
end
end
def select_merge_method_nodes(kwsplat)
extract_send_methods(kwsplat).select do |node|
mergeable?(node)
end
end
def opening_brace(node)
node.loc.begin.join(node.children.first.source_range.begin)
end
def closing_brace(node)
node.children.last.source_range.end.join(node.loc.end)
end
def autocorrect_merge_methods(corrector, merge_methods, kwsplat)
range = range_of_merge_methods(merge_methods)
new_kwsplat_arguments = extract_send_methods(kwsplat).map do |descendant|
convert_to_new_arguments(descendant)
end
new_source = new_kwsplat_arguments.compact.reverse.unshift('').join(', ')
corrector.replace(range, new_source)
end
def range_of_merge_methods(merge_methods)
begin_merge_method = merge_methods.last
end_merge_method = merge_methods.first
begin_merge_method.loc.dot.begin.join(end_merge_method.source_range.end)
end
def extract_send_methods(kwsplat)
kwsplat.each_descendant(:send, :csend)
end
def convert_to_new_arguments(node)
return unless mergeable?(node)
node.arguments.map do |arg|
if arg.hash_type?
arg.source
else
"**#{arg.source}"
end
end
end
def mergeable?(node)
return true unless node.call_type?
return false unless MERGE_METHODS.include?(node.method_name)
return true unless (parent = node.parent)
mergeable?(parent)
end
end
end
end
end