Class: RuboCop::Cop::Lint::IdentityComparison

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

Overview

Prefer ‘equal?` over `==` when comparing `object_id`.

‘Object#equal?` is provided to compare objects for identity, and in contrast `Object#==` is provided for the purpose of doing value comparison.

Examples:

# bad
foo.object_id == bar.object_id
foo.object_id != baz.object_id

# good
foo.equal?(bar)
!foo.equal?(baz)

Constant Summary collapse

MSG = 
'Use `%<bang>sequal?` instead of `%<comparison_method>s` when comparing `object_id`.'
RESTRICT_ON_SEND = 
%i[== !=].freeze

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, #string_literals_frozen_by_default?, support_autocorrect?, support_multiple_source?, #target_gem_version, #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

#object_id_comparison(node) ⇒ Object 



27
28
29
30
31
32
33
 
# File 'lib/rubocop/cop/lint/identity_comparison.rb', line 27

def_node_matcher :object_id_comparison, <<~PATTERN
  (send
    (send
      _lhs_receiver :object_id) ${:== :!=}
    (send
      _rhs_receiver :object_id))
PATTERN

#on_send(node) ⇒ Object 



35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
 
# File 'lib/rubocop/cop/lint/identity_comparison.rb', line 35

def on_send(node)
  return unless (comparison_method = object_id_comparison(node))

  bang = comparison_method == :== ? '' : '!'
  add_offense(node,
              message: format(MSG, comparison_method: comparison_method,
                                   bang: bang)) do |corrector|
    receiver = node.receiver.receiver
    argument = node.first_argument.receiver
    return unless receiver && argument

    replacement = "#{bang}#{receiver.source}.equal?(#{argument.source})"

    corrector.replace(node, replacement)
  end
end