Class: RuboCop::Cop::Style::ArrayCoercion

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Defined in:
lib/rubocop/cop/style/array_coercion.rb

Overview

Enforces the use of ‘Array()` instead of explicit `Array` check or `[*var]`.

The cop is disabled by default due to safety concerns.

Examples:

# bad
paths = [paths] unless paths.is_a?(Array)
paths.each { |path| do_something(path) }

# bad (always creates a new Array instance)
[*paths].each { |path| do_something(path) }

# good (and a bit more readable)
Array(paths).each { |path| do_something(path) }

Constant Summary collapse

SPLAT_MSG = 
'Use `Array(%<arg>s)` instead of `[*%<arg>s]`.'
CHECK_MSG = 
'Use `Array(%<arg>s)` instead of explicit `Array` check.'

Constants inherited from Base

Base::RESTRICT_ON_SEND

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods included from AutoCorrector

support_autocorrect?

Methods inherited from Base

#active_support_extensions_enabled?, #add_global_offense, #add_offense, #always_autocorrect?, autocorrect_incompatible_with, badge, #begin_investigation, callbacks_needed, #callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?, #cop_config, cop_name, #cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, #inspect, joining_forces, lint?, match?, #message, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #parse, #parser_engine, #ready, #relevant_file?, requires_gem, support_autocorrect?, support_multiple_source?, #target_rails_version, #target_ruby_version

Methods included from ExcludeLimit

#exclude_limit

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #autocorrect_with_disable_uncorrectable?, #correctable?, #disable_uncorrectable?, #safe_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

silence_warnings

Constructor Details

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

Instance Method Details

#array_splat?(node) ⇒ Object 



48
49
50
 
# File 'lib/rubocop/cop/style/array_coercion.rb', line 48

def_node_matcher :array_splat?, <<~PATTERN
  (array (splat $_))
PATTERN

#on_array(node) ⇒ Object 



63
64
65
66
67
68
69
70
71
72
 
# File 'lib/rubocop/cop/style/array_coercion.rb', line 63

def on_array(node)
  return unless node.square_brackets?

  array_splat?(node) do |arg_node|
    message = format(SPLAT_MSG, arg: arg_node.source)
    add_offense(node, message: message) do |corrector|
      corrector.replace(node, "Array(#{arg_node.source})")
    end
  end
end

#on_if(node) ⇒ Object 



74
75
76
77
78
79
80
81
82
83
 
# File 'lib/rubocop/cop/style/array_coercion.rb', line 74

def on_if(node)
  unless_array?(node) do |var_a, var_b, var_c|
    if var_a == var_b && var_c == var_b
      message = format(CHECK_MSG, arg: var_a)
      add_offense(node, message: message) do |corrector|
        corrector.replace(node, "#{var_a} = Array(#{var_a})")
      end
    end
  end
end

#unless_array?(node) ⇒ Object 



53
54
55
56
57
58
59
60
61
 
# File 'lib/rubocop/cop/style/array_coercion.rb', line 53

def_node_matcher :unless_array?, <<~PATTERN
  (if
    (send
      (lvar $_) :is_a?
      (const nil? :Array)) nil?
    (lvasgn $_
      (array
        (lvar $_))))
PATTERN