class RuboCop::Cop::Style::HashEachMethods

Checks for uses of ‘each_key` and `each_value` Hash methods.

NOTE: If you have an array of two-element arrays, you can put

parentheses around the block arguments to indicate that you're not
working with a hash, and suppress RuboCop offenses.

@safety

This cop is unsafe because it cannot be guaranteed that the receiver
is a `Hash`. The `AllowedReceivers` configuration can mitigate,
but not fully resolve, this safety issue.

@example

# bad
hash.keys.each { |k| p k }
hash.each { |k, unused_value| p k }

# good
hash.each_key { |k| p k }

# bad
hash.values.each { |v| p v }
hash.each { |unused_key, v| p v }

# good
hash.each_value { |v| p v }

@example AllowedReceivers: [‘execute’]

# good
execute(sql).keys.each { |v| p v }
execute(sql).values.each { |v| p v }

Constants

ARRAY_CONVERTER_METHODS
MSG
UNUSED_BLOCK_ARG_MSG

Public Instance Methods

check_unused_block_args(node, key, value) click to toggle source

rubocop:disable Metrics/AbcSize

# File lib/rubocop/cop/style/hash_each_methods.rb, line 79
def check_unused_block_args(node, key, value)
  return if node.body.nil?

  value_unused = unused_block_arg_exist?(node, value)
  key_unused = unused_block_arg_exist?(node, key)
  return if value_unused && key_unused

  if value_unused
    message = message('each_key', node.method_name, value.source)
    unused_range = key.source_range.end.join(value.source_range.end)

    register_each_args_offense(node, message, 'each_key', unused_range)
  elsif key_unused
    message = message('each_value', node.method_name, key.source)
    unused_range = key.source_range.begin.join(value.source_range.begin)

    register_each_args_offense(node, message, 'each_value', unused_range)
  end
end
on_block(node) click to toggle source
# File lib/rubocop/cop/style/hash_each_methods.rb, line 65
def on_block(node)
  return unless handleable?(node)

  kv_each(node) do |target, method|
    register_kv_offense(target, method) and return
  end

  return unless (key, value = each_arguments(node))

  check_unused_block_args(node, key, value)
end
Also aliased as: on_numblock
on_block_pass(node) click to toggle source

rubocop:enable Metrics/AbcSize

# File lib/rubocop/cop/style/hash_each_methods.rb, line 100
def on_block_pass(node)
  kv_each_with_block_pass(node.parent) do |target, method|
    register_kv_with_block_pass_offense(node, target, method)
  end
end
on_numblock(node)
Alias for: on_block

Private Instance Methods

check_argument(variable) click to toggle source
# File lib/rubocop/cop/style/hash_each_methods.rb, line 186
def check_argument(variable)
  return unless variable.block_argument?

  (@block_args ||= []).push(variable)
end
correct_args(node, corrector) click to toggle source
# File lib/rubocop/cop/style/hash_each_methods.rb, line 210
def correct_args(node, corrector)
  args = node.parent.arguments
  name, = *args.children.find { |arg| used?(arg) }

  corrector.replace(args, "|#{name}|")
end
correct_implicit(node, corrector, method_name) click to toggle source
# File lib/rubocop/cop/style/hash_each_methods.rb, line 196
def correct_implicit(node, corrector, method_name)
  corrector.replace(node, method_name)
  correct_args(node, corrector)
end
correct_key_value_each(node, corrector) click to toggle source
# File lib/rubocop/cop/style/hash_each_methods.rb, line 201
def correct_key_value_each(node, corrector)
  receiver = node.receiver.receiver
  name = "each_#{node.receiver.method_name.to_s.chop}"
  return correct_implicit(node, corrector, name) unless receiver

  new_source = receiver.source + "#{node.loc.dot.source}#{name}"
  corrector.replace(node, new_source)
end
format_message(method_name, current) click to toggle source
# File lib/rubocop/cop/style/hash_each_methods.rb, line 182
def format_message(method_name, current)
  format(MSG, prefer: "each_#{method_name[0..-2]}", current: current)
end
handleable?(node) click to toggle source
# File lib/rubocop/cop/style/hash_each_methods.rb, line 108
def handleable?(node)
  return false if use_array_converter_method_as_preceding?(node)
  return false unless (root_receiver = root_receiver(node))
  return false if hash_mutated?(node, root_receiver)

  !root_receiver.literal? || root_receiver.hash_type?
end
kv_range(outer_node) click to toggle source
# File lib/rubocop/cop/style/hash_each_methods.rb, line 217
def kv_range(outer_node)
  outer_node.receiver.loc.selector.join(outer_node.loc.selector)
end
message(prefer, method_name, unused_code) click to toggle source
# File lib/rubocop/cop/style/hash_each_methods.rb, line 139
def message(prefer, method_name, unused_code)
  format(
    UNUSED_BLOCK_ARG_MSG, prefer: prefer, current: method_name, unused_code: unused_code
  )
end
register_each_args_offense(node, message, prefer, unused_range) click to toggle source
# File lib/rubocop/cop/style/hash_each_methods.rb, line 145
def register_each_args_offense(node, message, prefer, unused_range)
  add_offense(node, message: message) do |corrector|
    corrector.replace(node.send_node.loc.selector, prefer)
    corrector.remove(unused_range)
  end
end
register_kv_offense(target, method) click to toggle source
# File lib/rubocop/cop/style/hash_each_methods.rb, line 116
def register_kv_offense(target, method)
  return unless (parent_receiver = target.receiver.receiver)
  return if allowed_receiver?(parent_receiver)

  current = target.receiver.loc.selector.join(target.source_range.end).source

  add_offense(kv_range(target), message: format_message(method, current)) do |corrector|
    correct_key_value_each(target, corrector)
  end
end
register_kv_with_block_pass_offense(node, target, method) click to toggle source
# File lib/rubocop/cop/style/hash_each_methods.rb, line 152
def register_kv_with_block_pass_offense(node, target, method)
  return unless (parent_receiver = node.parent.receiver.receiver)
  return if allowed_receiver?(parent_receiver)

  range = target.loc.selector.join(node.parent.loc.selector.end)

  add_offense(range, message: format_message(method, range.source)) do |corrector|
    corrector.replace(range, "each_#{method[0..-2]}")
  end
end
root_receiver(node) click to toggle source
# File lib/rubocop/cop/style/hash_each_methods.rb, line 173
def root_receiver(node)
  receiver = node.receiver
  if receiver&.receiver
    root_receiver(receiver)
  else
    receiver
  end
end
unused_block_arg_exist?(node, block_arg) click to toggle source
# File lib/rubocop/cop/style/hash_each_methods.rb, line 127
def unused_block_arg_exist?(node, block_arg)
  lvar_sources = node.body.each_descendant(:lvar).map(&:source)

  if block_arg.mlhs_type?
    block_arg.each_descendant(:arg, :restarg).all? do |block_arg|
      lvar_sources.none?(block_arg.source.delete_prefix('*'))
    end
  else
    lvar_sources.none?(block_arg.source.delete_prefix('*'))
  end
end
use_array_converter_method_as_preceding?(node) click to toggle source
# File lib/rubocop/cop/style/hash_each_methods.rb, line 163
def use_array_converter_method_as_preceding?(node)
  return false unless (preceding_method = node.children.first.children.first)
  unless preceding_method.call_type? ||
         preceding_method.block_type? || preceding_method.numblock_type?
    return false
  end

  ARRAY_CONVERTER_METHODS.include?(preceding_method.method_name)
end
used?(arg) click to toggle source
# File lib/rubocop/cop/style/hash_each_methods.rb, line 192
def used?(arg)
  @block_args.find { |var| var.declaration_node.loc == arg.loc }.used?
end