Class: RuboCop::Cop::Style::RedundantInitialize

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Includes:
CommentsHelp, RangeHelp
Defined in:
lib/rubocop/cop/style/redundant_initialize.rb

Overview

Checks for ‘initialize` methods that are redundant.

An initializer is redundant if it does not do anything, or if it only calls ‘super` with the same arguments given to it. If the initializer takes an argument that accepts multiple values (`restarg`, `kwrestarg`, etc.) it will not register an offense, because it allows the initializer to take a different number of arguments as its superclass potentially does.

NOTE: If an initializer takes any arguments and has an empty body, RuboCop assumes it to not be redundant. This is to prevent potential ‘ArgumentError`.

NOTE: If an initializer argument has a default value, RuboCop assumes it to not be redundant.

NOTE: Empty initializers are registered as offenses, but it is possible to purposely create an empty ‘initialize` method to override a superclass’s initializer.

Examples:

# bad
def initialize
end

# bad
def initialize
  super
end

# bad
def initialize(a, b)
  super
end

# bad
def initialize(a, b)
  super(a, b)
end

# good
def initialize
  do_something
end

# good
def initialize
  do_something
  super
end

# good (different number of parameters)
def initialize(a, b)
  super(a)
end

# good (default value)
def initialize(a, b = 5)
  super
end

# good (default value)
def initialize(a, b: 5)
  super
end

# good (changes the parameter requirements)
def initialize(_)
end

# good (changes the parameter requirements)
def initialize(*)
end

# good (changes the parameter requirements)
def initialize(**)
end

# good (changes the parameter requirements)
def initialize(...)
end

AllowComments: true (default)


# good
def initialize
  # Overriding to negate superclass `initialize` method.
end

AllowComments: false


# bad
def initialize
  # Overriding to negate superclass `initialize` method.
end

Constant Summary collapse

MSG = 
'Remove unnecessary `initialize` method.'
MSG_EMPTY = 
'Remove unnecessary empty `initialize` method.'

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 included from CommentsHelp

#comments_contain_disables?, #comments_in_range, #contains_comments?, #source_range_with_comment

Methods inherited from Base

#active_support_extensions_enabled?, #add_global_offense, #add_offense, #always_autocorrect?, autocorrect_incompatible_with, badge, #begin_investigation, #callbacks_needed, callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?, #cop_config, #cop_name, cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, #inspect, joining_forces, lint?, match?, #message, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #parse, #parser_engine, #ready, #relevant_file?, requires_gem, #string_literals_frozen_by_default?, support_autocorrect?, support_multiple_source?, #target_gem_version, #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

#initialize_forwards?(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/redundant_initialize.rb', line 115

def_node_matcher :initialize_forwards?, <<~PATTERN
  (def _ (args $arg*) $({super zsuper} ...))
PATTERN

#on_def(node) ⇒ Object 



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

def on_def(node)
  return if acceptable?(node)

  if node.body.nil?
    register_offense(node, MSG_EMPTY) if node.arguments.empty?
  else
    return if node.body.begin_type?

    if (args, super_node = initialize_forwards?(node))
      return unless same_args?(super_node, args)

      register_offense(node, MSG)
    end
  end
end