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?, #external_dependency_checksum, #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?, #safe_autocorrect?, #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)
  if node.block_type?
    correct_inverse_block(node)
  elsif node.send_type?
    correct_inverse_method(node)
  end
end

#correct_inverse_block(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/inverse_methods.rb', line 119

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_method(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/inverse_methods.rb', line 104

def correct_inverse_method(node)
  method_call, _lhs, method, _rhs = inverse_candidate?(node)
  return unless 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
end

#correct_inverse_selector(block, corrector) ⇒ Object 



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# File 'lib/rubocop/cop/style/inverse_methods.rb', line 129

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

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

    corrector.remove(selector_loc)
  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