Class: RuboCop::Cop::Style::ParallelAssignment

Inherits:
Cop
  • Object
show all
Includes:
IfNode
Defined in:
lib/rubocop/cop/style/parallel_assignment.rb

Overview

Checks for simple usages of parallel assignment. This will only complain when the number of variables being assigned matched the number of assigning variables.

Examples:

# bad
a, b, c = 1, 2, 3
a, b, c = [1, 2, 3]

# good
one, two = *foo
a, b = foo()
a, b = b, a

a = 1
b = 2
c = 3

Defined Under Namespace

Classes: AssignmentSorter, GenericCorrector, ModifierCorrector, RescueCorrector

Constant Summary collapse

MSG =
'Do not use parallel assignment.'

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 included from IfNode

#elsif?, #if_else?, #if_node_parts, #modifier_if?, #ternary_op?

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

#autocorrect(node) ⇒ Object


57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
# File 'lib/rubocop/cop/style/parallel_assignment.rb', line 57

def autocorrect(node)
  lambda do |corrector|
    left, right = *node
    left_elements = *left
    right_elements = [*right].compact
    order = find_valid_order(left_elements, right_elements)

    assignment_corrector =
      if modifier_statement?(node.parent)
        ModifierCorrector.new(node, config, order)
      elsif rescue_modifier?(node.parent)
        RescueCorrector.new(node, config, order)
      else
        GenericCorrector.new(node, config, order)
      end

    corrector.replace(assignment_corrector.correction_range,
                      assignment_corrector.correction)
  end
end

#on_masgn(node) ⇒ Object


30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
# File 'lib/rubocop/cop/style/parallel_assignment.rb', line 30

def on_masgn(node)
  left, right = *node
  left_elements = *left
  right_elements = [*right].compact # edge case for one constant

  # only complain when the number of variables matches
  return if left_elements.size != right_elements.size

  # account for edge cases using one variable with a comma
  return if left_elements.size == 1

  # account for edge case of Constant::CONSTANT
  return unless right.array_type?

  # allow mass assignment as the return of a method call
  return if right.block_type? || right.send_type?

  # allow mass assignment when using splat
  return if (left_elements + right_elements).any?(&:splat_type?)

  order = find_valid_order(left_elements, right_elements)
  # For `a, b = b, a` or similar, there is no valid order
  return if order.nil?

  add_offense(node, :expression)
end