Class: RuboCop::Cop::Style::InverseMethods

Inherits:
Cop
  • Object
show all
Includes:
IgnoredNode, RangeHelp
Defined in:
lib/rubocop/cop/style/inverse_methods.rb

Overview

This cop check for usages of not (not or !) called on a method when an inverse of that method can be used instead. Methods that can be inverted by a not (not or !) should be defined in InverseMethods Methods that are inverted by inverting the return of the block that is passed to the method should be defined in InverseBlocks

Examples:

# bad
!foo.none?
!foo.any? { |f| f.even? }
!foo.blank?
!(foo == bar)
foo.select { |f| !f.even? }
foo.reject { |f| f != 7 }

# good
foo.none?
foo.blank?
foo.any? { |f| f.even? }
foo != bar
foo == bar
!!('foo' =~ /^\w+$/)
!(foo.class < Numeric) # Checking class hierarchy is allowed
# Blocks with guard clauses are ignored:
foo.select do |f|
  next if f.zero?
  f != 1
end

Constant Summary collapse

MSG = 
'Use `%<inverse>s` instead of inverting `%<method>s`.'
CLASS_COMPARISON_METHODS = 
%i[<= >= < >].freeze
EQUALITY_METHODS = 
%i[== != =~ !~ <= >= < >].freeze
NEGATED_EQUALITY_METHODS = 
%i[!= !~].freeze
CAMEL_CASE = 
/[A-Z]+[a-z]+/.freeze

Constants included from Util

Util::LITERAL_REGEX

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Class Method Summary collapse

Instance Method Summary collapse

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods inherited from Cop

#add_offense, all, badge, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, #correct, department, #disable_uncorrectable, #duplicate_location?, #excluded_file?, #find_location, #highlights, inherited, #initialize, #join_force?, lint?, match?, #message, #messages, #parse, qualified_cop_name, #reason_to_not_correct, #relevant_file?, #target_rails_version, #target_ruby_version

Methods included from AST::Sexp

#s

Methods included from NodePattern::Macros

#def_node_matcher, #def_node_search, #node_search, #node_search_all, #node_search_body, #node_search_first

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #correctable?, #disable_offense, #disable_uncorrectable?, #support_autocorrect?

Methods included from Util

begins_its_line?, comment_line?, double_quotes_required?, escape_string, first_part_of_call_chain, interpret_string_escapes, line_range, needs_escaping?, on_node, parentheses?, same_line?, to_string_literal, to_supported_styles, tokens, trim_string_interporation_escape_character

Methods included from PathUtil

absolute?, chdir, hidden_dir?, hidden_file_in_not_hidden_dir?, match_path?, pwd, relative_path, reset_pwd, smart_path

Constructor Details

This class inherits a constructor from RuboCop::Cop::Cop

Class Method Details

.autocorrect_incompatible_with ⇒ Object 



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# File 'lib/rubocop/cop/style/inverse_methods.rb', line 46

def self.autocorrect_incompatible_with
  [Style::Not]
end

Instance Method Details

#autocorrect(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/inverse_methods.rb', line 96

def autocorrect(node)
  method_call, _lhs, method, _rhs = inverse_candidate?(node)

  if method_call && method
    lambda do |corrector|
      corrector.remove(not_to_receiver(node, method_call))
      corrector.replace(method_call.loc.selector,
                        inverse_methods[method].to_s)

      if EQUALITY_METHODS.include?(method)
        corrector.remove(end_parentheses(node, method_call))
      end
    end
  else
    correct_inverse_block(node)
  end
end

#correct_inverse_block(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/inverse_methods.rb', line 114

def correct_inverse_block(node)
  method_call, method, block = inverse_block?(node)

  lambda do |corrector|
    corrector.replace(method_call.loc.selector,
                      inverse_blocks[method].to_s)
    correct_inverse_selector(block, corrector)
  end
end

#correct_inverse_selector(block, corrector) ⇒ Object 



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# File 'lib/rubocop/cop/style/inverse_methods.rb', line 124

def correct_inverse_selector(block, corrector)
  selector = block.loc.selector.source

  if NEGATED_EQUALITY_METHODS.include?(selector.to_sym)
    selector[0] = '='
    corrector.replace(block.loc.selector, selector)
  else
    if block.loc.dot
      range = dot_range(block.loc)
      corrector.remove(range)
    end

    corrector.remove(block.loc.selector)
  end
end

#on_block(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/inverse_methods.rb', line 80

def on_block(node)
  inverse_block?(node) do |_method_call, method, block|
    return unless inverse_blocks.key?(method)
    return if negated?(node) && negated?(node.parent)
    return if node.each_node(:next).any?

    # Inverse method offenses inside of the block of an inverse method
    # offense, such as `y.reject { |key, _value| !(key =~ /c\d/) }`,
    # can cause auto-correction to apply improper corrections.
    ignore_node(block)
    add_offense(node,
                message: format(MSG, method: method,
                                     inverse: inverse_blocks[method]))
  end
end

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/inverse_methods.rb', line 66

def on_send(node)
  return if part_of_ignored_node?(node)

  inverse_candidate?(node) do |_method_call, lhs, method, rhs|
    return unless inverse_methods.key?(method)
    return if possible_class_hierarchy_check?(lhs, rhs, method)
    return if negated?(node)

    add_offense(node,
                message: format(MSG, method: method,
                                     inverse: inverse_methods[method]))
  end
end