Class: RuboCop::Cop::Style::InvertibleUnlessCondition

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

Overview

Checks for usages of unless which can be replaced by if with inverted condition. Code without unless is easier to read, but that is subjective, so this cop is disabled by default.

Methods that can be inverted should be defined in InverseMethods. Note that the relationship of inverse methods needs to be defined in both directions. For example,

InverseMethods:
  :!=: :==
  :even?: :odd?
  :odd?: :even?

will suggest both even? and odd? to be inverted, but only != (and not ==).

Examples:

# bad (simple condition)
foo unless !bar
foo unless x != y
foo unless x >= 10
foo unless x.even?

# good
foo if bar
foo if x == y
foo if x < 10
foo if x.odd?

# bad (complex condition)
foo unless x != y || x.even?

# good
foo if x == y && x.odd?

# good (if)
foo if !condition

Cop Safety Information:

  • This cop is unsafe because it cannot be guaranteed that the method and its inverse method are both defined on receiver, and also are actually inverse of each other.

Constant Summary collapse

MSG = 
'Favor `if` with inverted condition over `unless`.'

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, autocorrect_incompatible_with, badge, #begin_investigation, 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, #inspect, joining_forces, lint?, match?, #message, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #parse, #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?, #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_if(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/invertible_unless_condition.rb', line 56

def on_if(node)
  return unless node.unless?

  condition = node.condition
  return unless invertible?(condition)

  add_offense(node) do |corrector|
    corrector.replace(node.loc.keyword, node.inverse_keyword)
    autocorrect(corrector, condition)
  end
end