Class: RuboCop::Cop::Style::IfWithBooleanLiteralBranches

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

Overview

Checks for redundant if with boolean literal branches. It checks only conditions to return boolean value (true or false) for safe detection. The conditions to be checked are comparison methods, predicate methods, and double negation (!!). nonzero? method is allowed by default. These are customizable with AllowedMethods option.

This cop targets only ifs with a single elsif or else branch. The following code will be allowed, because it has two elsif branches:

[source,ruby]

if foo true elsif bar > baz true elsif qux > quux # Single elsif is warned, but two or more elsifs are not. true else false end

Examples:

# bad
if foo == bar
  true
else
  false
end

# bad
foo == bar ? true : false

# good
foo == bar
# bad
if foo.do_something?
  true
else
  false
end

# good (but potentially an unsafe correction)
foo.do_something?

AllowedMethods: ['nonzero?'] (default)

# good
num.nonzero? ? true : false

Constant Summary collapse

MSG = 
'Remove redundant %<keyword>s with boolean literal branches.'
MSG_FOR_ELSIF = 
'Use `else` instead of redundant `elsif` with boolean literal branches.'

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, 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, joining_forces, lint?, match?, #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

#double_negative?(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/if_with_boolean_literal_branches.rb', line 74

def_node_matcher :double_negative?, '(send (send _ :!) :!)'

#if_with_boolean_literal_branches?(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/if_with_boolean_literal_branches.rb', line 70

def_node_matcher :if_with_boolean_literal_branches?, <<~PATTERN
  (if #return_boolean_value? {(true) (false) | (false) (true)})
PATTERN

#on_if(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/if_with_boolean_literal_branches.rb', line 76

def on_if(node)
  return if !if_with_boolean_literal_branches?(node) || multiple_elsif?(node)

  condition = node.condition
  range, keyword = offense_range_with_keyword(node, condition)

  add_offense(range, message: message(node, keyword)) do |corrector|
    replacement = replacement_condition(node, condition)

    if node.elsif?
      corrector.insert_before(node, "else\n")
      corrector.replace(node, "#{indent(node.if_branch)}#{replacement}")
    else
      corrector.replace(node, replacement)
    end
  end
end