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

[View source]

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# 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

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

def_node_matcher :simple_comparison_lhs, <<~PATTERN
  (send ${lvar call} :== $_)
PATTERN

#simple_comparison_rhs(node) ⇒ Object

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

def_node_matcher :simple_comparison_rhs, <<~PATTERN
  (send $_ :== ${lvar call})
PATTERN

#simple_double_comparison?(node) ⇒ Object

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

def_node_matcher :simple_double_comparison?, <<~PATTERN
  (send lvar :== lvar)
PATTERN