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Class: RuboCop::Cop::Style::ReturnNil

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ::RuboCop::Cop::AutoCorrector, ::RuboCop::Cop::Base, ::RuboCop::ExcludeLimit, NodePattern::Macros, RuboCop::AST::Sexp
Instance Chain:
self, ::RuboCop::Cop::ConfigurableEnforcedStyle, ::RuboCop::Cop::Base, ::RuboCop::Cop::AutocorrectLogic, ::RuboCop::Cop::IgnoredNode, ::RuboCop::Util, RuboCop::AST::Sexp
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/style/return_nil.rb

Overview

Enforces consistency between return nil and return.

This cop is disabled by default. Because there seems to be a perceived semantic difference between return and return nil. The former can be seen as just halting evaluation, while the latter might be used when the return value is of specific concern.

Supported styles are return and return_nil.

Examples:

EnforcedStyle: return (default)

# bad
def foo(arg)
  return nil if arg
end

# good
def foo(arg)
  return if arg
end

EnforcedStyle: return_nil

# bad
def foo(arg)
  return if arg
end

# good
def foo(arg)
  return nil if arg
end

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

::RuboCop::Cop::ConfigurableEnforcedStyle - Included

SYMBOL_TO_STRING_CACHE

Class Attribute Summary

::RuboCop::Cop::AutoCorrector - Extended

support_autocorrect?

::RuboCop::Cop::Base - Inherited

.gem_requirements, .lint?,
.support_autocorrect?

Returns if class supports autocorrect.
.support_multiple_source?

Override if your cop should be called repeatedly for multiple investigations Between calls to on_new_investigation and on_investigation_end, the result of processed_source will remain constant.

Class Method Summary

::RuboCop::Cop::Base - Inherited

.autocorrect_incompatible_with

List of cops that should not try to autocorrect at the same time as this cop.
.badge

Naming.
.callbacks_needed, .cop_name, .department,
.documentation_url

Returns a url to view this cops documentation online.
.exclude_from_registry

Call for abstract Cop classes.
.inherited,
.joining_forces

Override and return the Force class(es) you need to join.
.match?

Returns true if the cop name or the cop namespace matches any of the given names.
.new,
.requires_gem

Register a version requirement for the given gem name.
.restrict_on_send

::RuboCop::ExcludeLimit - Extended

exclude_limit

Sets up a configuration option to have an exclude limit tracked.
transform

Instance Attribute Summary

::RuboCop::Cop::ConfigurableEnforcedStyle - Included

#detected_style, #detected_style=, #no_acceptable_style?, #style_configured?

::RuboCop::Cop::Base - Inherited

#active_support_extensions_enabled?, #always_autocorrect?, #config, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?, #processed_source, #string_literals_frozen_by_default?, #target_satisfies_all_gem_version_requirements?

::RuboCop::Cop::AutocorrectLogic - Included

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #autocorrect_with_disable_uncorrectable?, #correctable?, #disable_uncorrectable?, #safe_autocorrect?

Instance Method Summary

::RuboCop::Cop::ConfigurableEnforcedStyle - Included

#alternative_style, #alternative_styles, #ambiguous_style_detected,
#conflicting_styles_detected

Alias for ConfigurableEnforcedStyle#no_acceptable_style!.
#correct_style_detected, #no_acceptable_style!, #opposite_style_detected, #style, #style_detected, #style_parameter_name, #supported_styles, #unexpected_style_detected,
#unrecognized_style_detected

Alias for ConfigurableEnforcedStyle#no_acceptable_style!.

::RuboCop::Cop::Base - Inherited

#add_global_offense

Adds an offense that has no particular location.
#add_offense

Adds an offense on the specified range (or node with an expression) Unless that offense is disabled for this range, a corrector will be yielded to provide the cop the opportunity to autocorrect the offense.
#begin_investigation

Called before any investigation.
#callbacks_needed,
#cop_config

Configuration Helpers.
#cop_name, #excluded_file?,
#external_dependency_checksum

This method should be overridden when a cop’s behavior depends on state that lives outside of these locations:
#inspect,
#message

Gets called if no message is specified when calling add_offense or add_global_offense Cops are discouraged to override this; instead pass your message directly.
#name

Alias for Base#cop_name.
#offenses,
#on_investigation_end

Called after all on_…​
#on_new_investigation

Called before all on_…​
#on_other_file

Called instead of all on_…​
#parse

There should be very limited reasons for a Cop to do it’s own parsing.
#parser_engine,
#ready

Called between investigations.
#relevant_file?, #target_rails_version, #target_ruby_version, #annotate, #apply_correction, #attempt_correction,
#callback_argument

Reserved for Cop::Cop.
#complete_investigation

Called to complete an investigation.
#correct, #current_corrector,
#current_offense_locations

Reserved for Commissioner:
#current_offenses, #currently_disabled_lines, #custom_severity, #default_severity, #disable_uncorrectable, #enabled_line?, #file_name_matches_any?, #find_message, #find_severity, #range_for_original, #range_from_node_or_range,
#reset_investigation

Actually private methods.
#use_corrector

::RuboCop::Cop::AutocorrectLogic - Included

#disable_offense, #disable_offense_at_end_of_line, #disable_offense_before_and_after, #disable_offense_with_eol_or_surround_comment, #max_line_length,
#range_by_lines

Expand the given range to include all of any lines it covers.
#range_of_first_line, #range_overlaps_offense?, #string_continuation, #string_continuation?, #surrounding_heredoc, #surrounding_percent_array

::RuboCop::Cop::IgnoredNode - Included

#ignore_node, #ignored_node?, #part_of_ignored_node?, #ignored_nodes

Constructor Details

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

Instance Method Details

#chained_send?(node) (private)

[ GitHub ] 

  


# File 'lib/rubocop/cop/style/return_nil.rb', line 90



def_node_matcher :chained_send?, '(send !nil? ...)'


  








  

    #correct_style?(node)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


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



def correct_style?(node)
  (style == :return && !return_nil_node?(node)) ||
    (style == :return_nil && !return_node?(node))
end


  








  

    #define_method?(node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/return_nil.rb', line 93



def_node_matcher :define_method?, <<~PATTERN
  (send _ {:define_method :define_singleton_method} _)
PATTERN


  








  

    #message(_node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/return_nil.rb', line 76



def message(_node)
  style == :return ? RETURN_MSG : RETURN_NIL_MSG
end


  








  

    #on_return(node)  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/return_nil.rb', line 48



def on_return(node)
  # Check Lint/NonLocalExitFromIterator first before this cop
  node.each_ancestor(:block, :def, :defs) do |n|
    break if scoped_node?(n)

    send_node, args_node, _body_node = *n

    # if a proc is passed to `Module#define_method` or
    # `Object#define_singleton_method`, `return` will not cause a
    # non-local exit error
    break if define_method?(send_node)

    next if args_node.children.empty?

    return nil if chained_send?(send_node)
  end

  return if correct_style?(node)

  add_offense(node) do |corrector|
    corrected = style == :return ? 'return' : 'return nil'

    corrector.replace(node, corrected)
  end
end


  








  

    #return_nil_node?(node)  
  

  [ GitHub ]


  

  


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



def_node_matcher :return_nil_node?, '(return nil)'


  








  

    #return_node?(node)  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/return_nil.rb', line 43



def_node_matcher :return_node?, '(return)'


  








  

    #scoped_node?(node)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/return_nil.rb', line 85



def scoped_node?(node)
  node.def_type? || node.defs_type? || node.lambda?
end