Class: RuboCop::Cop::Lint::NonLocalExitFromIterator

Inherits:
Cop
  • Object
show all
Defined in:
lib/rubocop/cop/lint/non_local_exit_from_iterator.rb

Overview

This cop checks for non-local exit from iterator, without return value. It warns only when satisfies all of these: return doesn't have return value, the block is preceded by a method chain, the block has arguments, and the method which receives the block is not define_method.

Examples:


class ItemApi
  rescue_from ValidationError do |e| # non-iteration block with arg
    return message: 'validation error' unless e.errors # allowd
    error_array = e.errors.map do |error| # block with method chain
      return if error.suppress? # warned
      return "#{error.param}: invalid" unless error.message # allowed
      "#{error.param}: #{error.message}"
    end
    message: 'validation error', errors: error_array
  end

  def update_items
    transaction do # block without arguments
      return unless update_necessary? # allowed
      find_each do |item| # block without method chain
        return if item.stock == 0 # false-negative...
        item.update!(foobar: true)
      end
    end
  end
end

Constant Summary collapse

MSG =
'Non-local exit from iterator, without return value. ' \
'`next`, `break`, `Array#find`, `Array#any?`, etc. is preferred.'

Constants included from Util

Util::ASGN_NODES, Util::BASIC_LITERALS, Util::EQUALS_ASGN_NODES, Util::LITERALS, Util::OPERATOR_METHODS, Util::PROC_NEW_NODE, Util::SHORTHAND_ASGN_NODES

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

Methods inherited from Cop

#add_offense, all, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, cop_type, #correct, #debug?, #details, #display_cop_names?, #display_style_guide?, #excluded_file?, #extra_details?, inherited, #initialize, #join_force?, lint?, match?, #message, non_rails, qualified_cop_name, rails?, #reference_url, #relevant_file?, #style_guide_url

Methods included from NodePattern::Macros

#def_node_matcher, #def_node_search

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

begins_its_line?, block_length, command?, comment_line?, const_name, directions, first_part_of_call_chain, lambda?, lambda_or_proc?, line_range, move_pos, numeric_range_size, on_node, operator?, parentheses?, proc?, range_with_surrounding_comma, range_with_surrounding_space, source_range, strip_quotes, within_node?

Methods included from PathUtil

hidden?, issue_deprecation_warning, match_path?, relative_path

Constructor Details

This class inherits a constructor from RuboCop::Cop::Cop

Instance Method Details

#chained_send?(send_node) ⇒ Boolean

Returns:

  • (Boolean)

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# File 'lib/rubocop/cop/lint/non_local_exit_from_iterator.rb', line 62

def chained_send?(send_node)
  receiver_node, _selector_node = *send_node
  !receiver_node.nil?
end

#define_method?(send_node) ⇒ Boolean

Returns:

  • (Boolean)

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# File 'lib/rubocop/cop/lint/non_local_exit_from_iterator.rb', line 72

def define_method?(send_node)
  _receiver, selector = *send_node
  selector == :define_method
end

#lambda?(send_node) ⇒ Boolean

Returns:

  • (Boolean)

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# File 'lib/rubocop/cop/lint/non_local_exit_from_iterator.rb', line 67

def lambda?(send_node)
  receiver_node, selector_node = *send_node
  receiver_node.nil? && selector_node == :lambda
end

#on_return(return_node) ⇒ Object


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# File 'lib/rubocop/cop/lint/non_local_exit_from_iterator.rb', line 39

def on_return(return_node)
  return if return_value?(return_node)
  return_node.each_ancestor(:block) do |block_node|
    send_node, args_node, _body_node = *block_node

    # `return` does not exit to outside of lambda block, this is safe.
    break if lambda?(send_node)
    # if a proc is passed to `Module#define_method`, `return` will not
    # cause a non-local exit error
    break if define_method?(send_node)

    next if args_node.children.empty?
    if chained_send?(send_node)
      add_offense(return_node, :keyword)
      break
    end
  end
end

#return_value?(return_node) ⇒ Boolean

Returns:

  • (Boolean)

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# File 'lib/rubocop/cop/lint/non_local_exit_from_iterator.rb', line 58

def return_value?(return_node)
  !return_node.children.empty?
end