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Class: RuboCop::Cop::Style::RedundantReturn

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::RangeHelp, ::RuboCop::Cop::Base, ::RuboCop::Cop::AutocorrectLogic, ::RuboCop::Cop::IgnoredNode, ::RuboCop::Util, RuboCop::AST::Sexp
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/style/redundant_return.rb

Overview

Checks for redundant return expressions.

Examples:

# These bad cases should be extended to handle methods whose body is
# if/else or a case expression with a default branch.

# bad
def test
  return something
end

# bad
def test
  one
  two
  three
  return something
end

# bad
def test
  return something if something_else
end

# good
def test
  something if something_else
end

# good
def test
  if x
  elsif y
  else
  end
end

AllowMultipleReturnValues: false (default)

# bad
def test
  return x, y
end

AllowMultipleReturnValues: true

# good
def test
  return x, y
end

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

::RuboCop::Cop::RangeHelp - Included

BYTE_ORDER_MARK, NOT_GIVEN

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.
.builtin?

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

Cops (other than builtin) are encouraged to implement this.
.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::Base - Inherited

#active_support_extensions_enabled?, #always_autocorrect?, #config, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?, #processed_source, #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::RangeHelp - Included

#add_range, #column_offset_between,
#contents_range

A range containing only the contents of a literal with delimiters (e.g.
#directions,
#effective_column

Returns the column attribute of the range, except if the range is on the first line and there’s a byte order mark at the beginning of that line, in which case 1 is subtracted from the column value.
#final_pos, #move_pos, #move_pos_str, #range_between, #range_by_whole_lines, #range_with_comments, #range_with_comments_and_lines, #range_with_surrounding_comma, #range_with_surrounding_space, #source_range

::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, #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, #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 Attribute Details

#allow_multiple_return_values? ⇒ Boolean (readonly, private)

[ GitHub ] 

  


# File 'lib/rubocop/cop/style/redundant_return.rb', line 175



def allow_multiple_return_values?
  cop_config['AllowMultipleReturnValues'] || false
end


  







Instance Method Details



  

    #add_braces(corrector, node)   (private)
  

  [ GitHub ]


  

  


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



def add_braces(corrector, node)
  corrector.insert_before(node.children.first, '{')
  corrector.insert_after(node.children.last, '}')
end


  








  

    #add_brackets(corrector, node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_return.rb', line 99



def add_brackets(corrector, node)
  corrector.insert_before(node.children.first, '[')
  corrector.insert_after(node.children.last, ']')
end


  








  

    #check_begin_node(node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_return.rb', line 170



def check_begin_node(node)
  last_expr = node.children.last
  check_branch(last_expr)
end


  








  

    #check_branch(node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_return.rb', line 110



def check_branch(node)
  return unless node

  case node.type
  when :return then check_return_node(node)
  when :case   then check_case_node(node)
  when :case_match then check_case_match_node(node)
  when :if     then check_if_node(node)
  when :rescue then check_rescue_node(node)
  when :resbody then check_resbody_node(node)
  when :ensure then check_ensure_node(node)
  when :begin, :kwbegin
    check_begin_node(node)
  end
end


  








  

    #check_case_match_node(node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_return.rb', line 144



def check_case_match_node(node)
  node.in_pattern_branches.each { |in_pattern_node| check_branch(in_pattern_node.body) }
  check_branch(node.else_branch)
end


  








  

    #check_case_node(node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_return.rb', line 139



def check_case_node(node)
  node.when_branches.each { |when_node| check_branch(when_node.body) }
  check_branch(node.else_branch)
end


  








  

    #check_ensure_node(node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_return.rb', line 165



def check_ensure_node(node)
  rescue_node = node.node_parts[0]
  check_branch(rescue_node)
end


  








  

    #check_if_node(node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_return.rb', line 149



def check_if_node(node)
  return if node.ternary?

  check_branch(node.if_branch)
  check_branch(node.else_branch)
end


  








  

    #check_resbody_node(node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_return.rb', line 161



def check_resbody_node(node)
  check_branch(node.body)
end


  








  

    #check_rescue_node(node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_return.rb', line 156



def check_rescue_node(node)
  node.branches.each { |branch| check_branch(branch) }
  check_branch(node.body) unless node.else?
end


  








  

    #check_return_node(node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_return.rb', line 127



def check_return_node(node)
  return if cop_config['AllowMultipleReturnValues'] && node.children.size > 1

  add_offense(node.loc.keyword, message: message(node)) do |corrector|
    if node.arguments?
      correct_with_arguments(node, corrector)
    else
      correct_without_arguments(node, corrector)
    end
  end
end


  








  

    #correct_with_arguments(return_node, corrector)   (private)
  

  [ GitHub ]


  

  


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



def correct_with_arguments(return_node, corrector)
  if return_node.children.size > 1
    add_brackets(corrector, return_node)
  elsif hash_without_braces?(return_node.first_argument)
    add_braces(corrector, return_node.first_argument)
  end
  if return_node.splat_argument?
    first_argument = return_node.first_argument
    corrector.replace(first_argument, first_argument.source.delete_prefix('*'))
  end

  keyword = range_with_surrounding_space(return_node.loc.keyword, side: :right)
  corrector.remove(keyword)
end


  








  

    #correct_without_arguments(return_node, corrector)   (private)
  

  [ GitHub ]


  

  


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



def correct_without_arguments(return_node, corrector)
  corrector.replace(return_node, 'nil')
end


  








  

    #hash_without_braces?(node)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_return.rb', line 95



def hash_without_braces?(node)
  node.hash_type? && !node.braces?
end


  








  

    #message(node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_return.rb', line 179



def message(node)
  if !allow_multiple_return_values? && node.children.size > 1
    "#{MSG} #{MULTI_RETURN_MSG}"
  else
    MSG
  end
end


  








  

    #on_def(node)  
    Also known as: #on_defs
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_return.rb', line 69



def on_def(node)
  check_branch(node.body)
end


  








  

    #on_defs(node)  
  



  

    


Alias for #on_def.



  



  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_return.rb', line 72



alias on_defs on_def


  








  

    #on_send(node)  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_return.rb', line 63



def on_send(node)
  return unless (parent = node.parent) && parent.block_type?

  check_branch(parent.body)
end