Class: RuboCop::Cop::Style::MultipleComparison

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

Overview

Checks against comparing a variable with multiple items, where ‘Array#include?`, `Set#include?` or a case could be used instead to avoid code repetition. It accepts comparisons of multiple method calls to avoid unnecessary method calls by default. It can be configured by AllowMethodComparison option.

Examples:

# bad
a = 'a'
foo if a == 'a' || a == 'b' || a == 'c'

# good
a = 'a'
foo if ['a', 'b', 'c'].include?(a)

VALUES = Set['a', 'b', 'c'].freeze
# elsewhere...
foo if VALUES.include?(a)

case foo
when 'a', 'b', 'c' then foo
# ...
end

# accepted (but consider `case` as above)
foo if a == b.lightweight || a == b.heavyweight

AllowMethodComparison: true (default)

# good
foo if a == b.lightweight || a == b.heavyweight

AllowMethodComparison: false

# bad
foo if a == b.lightweight || a == b.heavyweight

# good
foo if [b.lightweight, b.heavyweight].include?(a)

ComparisonsThreshold: 2 (default)

# bad
foo if a == 'a' || a == 'b'

ComparisonsThreshold: 3

# good
foo if a == 'a' || a == 'b'

Constant Summary collapse

MSG = 
'Avoid comparing a variable with multiple items ' \
'in a conditional, use `Array#include?` instead.'

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, #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

#on_or(node) ⇒ Object

rubocop:disable Metrics/AbcSize



74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
 
# File 'lib/rubocop/cop/style/multiple_comparison.rb', line 74

def on_or(node)
  root_of_or_node = root_of_or_node(node)
  return unless node == root_of_or_node
  return unless nested_comparison?(node)

  return unless (variable, values = find_offending_var(node))
  return if values.size < comparisons_threshold

  range = offense_range(values)

  add_offense(range) do |corrector|
    elements = values.map(&:source).join(', ')
    argument = variable.lvar_type? ? variable_name(variable) : variable.source
    prefer_method = "[#{elements}].include?(#{argument})"

    corrector.replace(range, prefer_method)
  end
end

#simple_comparison_lhs(node) ⇒ Object 



64
65
66
 
# File 'lib/rubocop/cop/style/multiple_comparison.rb', line 64

def_node_matcher :simple_comparison_lhs, "(send ${lvar call} :== $_)\n"

#simple_comparison_rhs(node) ⇒ Object 



69
70
71
 
# File 'lib/rubocop/cop/style/multiple_comparison.rb', line 69

def_node_matcher :simple_comparison_rhs, "(send $_ :== ${lvar call})\n"

#simple_double_comparison?(node) ⇒ Object 



59
60
61
 
# File 'lib/rubocop/cop/style/multiple_comparison.rb', line 59

def_node_matcher :simple_double_comparison?, "(send lvar :== lvar)\n"