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

Inherits:
Cop
  • Object
show all
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+$/)

Constant Summary collapse

MSG = 
'Use `%<inverse>s` instead of inverting `%<method>s`.'.freeze
EQUALITY_METHODS = 
%i[== != =~ !~ <= >= < >].freeze

Constants included from Util

Util::ASGN_NODES, Util::BYTE_ORDER_MARK, Util::CONDITIONAL_NODES, Util::EQUALS_ASGN_NODES, Util::LITERAL_REGEX, Util::LOGICAL_OPERATOR_NODES, Util::MODIFIER_NODES, Util::OPERATOR_METHODS, Util::SHORTHAND_ASGN_NODES

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

Methods inherited from Cop

#add_offense, all, autocorrect_incompatible_with, badge, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, #correct, department, #duplicate_location?, #excluded_file?, #find_location, #highlights, inherited, #initialize, #join_force?, lint?, match?, #message, #messages, non_rails, #parse, qualified_cop_name, #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?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

begins_its_line?, block_length, comment_line?, compatible_external_encoding_for?, directions, double_quotes_required?, effective_column, ends_its_line?, escape_string, first_part_of_call_chain, interpret_string_escapes, line_distance, line_range, move_pos, needs_escaping?, on_node, operator?, parentheses?, parenthesized_call?, preceed?, range_between, range_by_whole_lines, range_with_surrounding_comma, range_with_surrounding_space, same_line?, source_range, strip_quotes, stripped_source_upto, symbol_without_quote?, to_string_literal, to_supported_styles, to_symbol_literal, within_node?

Methods included from PathUtil

absolute?, match_path?, relative_path, smart_path

Constructor Details

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

Instance Method Details

#autocorrect(node) ⇒ Object 



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

def autocorrect(node)
  method_call, method = 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 92

def correct_inverse_block(node)
  method_call, method, block = inverse_block?(node)
  selector = block.loc.selector.source

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

    if ['!=', '!~'].include?(selector)
      selector[0] = '='
      corrector.replace(block.loc.selector, selector)
    else
      corrector.remove(block.loc.selector)
    end
  end
end

#on_block(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/inverse_methods.rb', line 62

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)

    add_offense(node,
                :expression,
                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 50

def on_send(node)
  inverse_candidate?(node) do |_method_call, method|
    return unless inverse_methods.key?(method)
    return if negated?(node)

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