class RuboCop::Cop::Style::RedundantDoubleSplatHashBraces


do_something(foo: bar, baz: qux, **options)
# good
do_something(**{foo: bar, baz: qux}.merge(options))
# bad
do_something(foo: bar, baz: qux)
# good
do_something(**{foo: bar, baz: qux})
# bad
@example
Checks for redundant uses of double splat hash braces.

def allowed_double_splat_receiver?(kwsplat)

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)

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 autocorrect_merge_methods(corrector, merge_methods, kwsplat)

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 closing_brace(node)

def closing_brace(node)
  node.children.last.source_range.end.join(node.loc.end)
end

def convert_to_new_arguments(node)

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 extract_send_methods(kwsplat)

def extract_send_methods(kwsplat)
  kwsplat.each_descendant(:send, :csend)
end

def mergeable?(node)

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

def on_hash(node)

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

def opening_brace(node)

def opening_brace(node)
  node.loc.begin.join(node.children.first.source_range.begin)
end

def range_of_merge_methods(merge_methods)

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 root_receiver(node)

def root_receiver(node)
  receiver = node.receiver
  if receiver&.receiver
    root_receiver(receiver)
  else
    receiver
  end
end

def select_merge_method_nodes(kwsplat)

def select_merge_method_nodes(kwsplat)
  extract_send_methods(kwsplat).select do |node|
    mergeable?(node)
  end
end