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, #project_index

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

cop_dir_for, #exclude_limit, read_limits

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 



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# File 'lib/rubocop/cop/style/multiple_comparison.rb', line 73

def on_or(node)
  return unless node == root_of_or_node(node)
  return unless nested_comparison?(node)
  return unless (variable, values, skipped = find_offending_var(node))
  return if values.size < comparisons_threshold

  range = offense_range(values)
  # Bail when an allowed method comparison sits between the collected
  # values: collapsing them into a single `include?` would drop it.
  return if skipped_within_range?(skipped, range)

  add_offense(range) do |corrector|
    corrector.replace(range, preferred_method(variable, values))
  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