Class: RuboCop::Cop::Style::ClassEqualityComparison

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Includes:
IgnoredMethods, RangeHelp
Defined in:
lib/rubocop/cop/style/class_equality_comparison.rb

Overview

This cop enforces the use of ‘Object#instance_of?` instead of class comparison for equality.

Examples:

# bad
var.class == Date
var.class.equal?(Date)
var.class.eql?(Date)
var.class.name == 'Date'

# good
var.instance_of?(Date)

Constant Summary collapse

MSG = 
'Use `instance_of?(%<class_name>s)` instead of comparing classes.'
RESTRICT_ON_SEND = 
%i[== equal? eql?].freeze

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods included from AutoCorrector

support_autocorrect?

Methods included from IgnoredMethods

#ignored_method?, #ignored_methods, included

Methods inherited from Base

#add_global_offense, #add_offense, autocorrect_incompatible_with, badge, #callbacks_needed, callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, #cop_name, cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, joining_forces, lint?, match?, #message, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #ready, #relevant_file?, 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?, #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

#class_comparison_candidate?(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/class_equality_comparison.rb', line 29

def_node_matcher :class_comparison_candidate?, <<~PATTERN
  (send
    {$(send _ :class) (send $(send _ :class) :name)}
    {:== :equal? :eql?} $_)
PATTERN

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/class_equality_comparison.rb', line 35

def on_send(node)
  def_node = node.each_ancestor(:def, :defs).first
  return if def_node && ignored_method?(def_node.method_name)

  class_comparison_candidate?(node) do |receiver_node, class_node|
    range = offense_range(receiver_node, node)
    class_name = class_name(class_node, node)

    add_offense(range, message: format(MSG, class_name: class_name)) do |corrector|
      corrector.replace(range, "instance_of?(#{class_name})")
    end
  end
end