Class: RubbyCop::Cop::Style::InverseMethods

Inherits:
Cop
  • Object
show all
Defined in:
lib/rubbycop/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

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, 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

Constructor Details

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

Instance Method Details

#autocorrect(node) ⇒ Object 



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# File 'lib/rubbycop/cop/style/inverse_methods.rb', line 71

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/rubbycop/cop/style/inverse_methods.rb', line 89

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

#end_parentheses(node, method_call) ⇒ Object 



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# File 'lib/rubbycop/cop/style/inverse_methods.rb', line 122

def end_parentheses(node, method_call)
  Parser::Source::Range.new(node.loc.expression.source_buffer,
                            method_call.loc.expression.end_pos,
                            node.loc.expression.end_pos)
end

#inverse_blocks ⇒ Object 



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# File 'lib/rubbycop/cop/style/inverse_methods.rb', line 111

def inverse_blocks
  @inverse_blocks ||= cop_config['InverseBlocks']
                      .merge(cop_config['InverseBlocks'].invert)
end

#inverse_methods ⇒ Object 



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# File 'lib/rubbycop/cop/style/inverse_methods.rb', line 106

def inverse_methods
  @inverse_methods ||= cop_config['InverseMethods']
                       .merge(cop_config['InverseMethods'].invert)
end

#not_to_receiver(node, method_call) ⇒ Object 



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# File 'lib/rubbycop/cop/style/inverse_methods.rb', line 116

def not_to_receiver(node, method_call)
  Parser::Source::Range.new(node.loc.expression.source_buffer,
                            node.loc.selector.begin_pos,
                            method_call.loc.expression.begin_pos)
end

#on_block(node) ⇒ Object 



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# File 'lib/rubbycop/cop/style/inverse_methods.rb', line 60

def on_block(node)
  inverse_block?(node) do |_method_call, method, _block|
    return unless inverse_blocks.key?(method)

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

#on_send(node) ⇒ Object 



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# File 'lib/rubbycop/cop/style/inverse_methods.rb', line 49

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

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