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,

source,yaml

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?
foo unless odd?

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

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

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

# good (if)
foo if !condition

Constant Summary collapse

MSG = 
'Prefer `%<prefer>s` over `%<current>s`.'

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_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 58

def on_if(node)
  return unless node.unless?

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

  message = format(MSG, prefer: "#{node.inverse_keyword} #{preferred_condition(condition)}",
                        current: "#{node.keyword} #{condition.source}")

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