123456789_123456789_123456789_123456789_123456789_

Class: RuboCop::Cop::Lint::SelfAssignment

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

Overview

Checks for self-assignments.

Examples:

# bad
foo = foo
foo, bar = foo, bar
Foo = Foo
hash['foo'] = hash['foo']
obj.attr = obj.attr

# good
foo = bar
foo, bar = bar, foo
Foo = Bar
hash['foo'] = hash['bar']
obj.attr = obj.attr2

# good (method calls possibly can return different results)
hash[foo] = hash[foo]

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

Class Attribute Summary

::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::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 Method Details

#handle_attribute_assignment(node) (private)

[ GitHub ] 

  


# File 'lib/rubocop/cop/lint/self_assignment.rb', line 103



def handle_attribute_assignment(node)
  first_argument = node.first_argument
  return unless first_argument.respond_to?(:arguments) && first_argument.arguments.empty?

  if first_argument.call_type? &&
     node.receiver == first_argument.receiver &&
     first_argument.method_name.to_s == node.method_name.to_s.delete_suffix('=')
    add_offense(node)
  end
end


  








  

    #handle_key_assignment(node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/self_assignment.rb', line 92



def handle_key_assignment(node)
  value_node = node.arguments[1]

  if value_node.send_type? && value_node.method?(:[]) &&
     node.receiver == value_node.receiver &&
     !node.first_argument.call_type? &&
     node.first_argument == value_node.first_argument
    add_offense(node)
  end
end


  








  

    #multiple_self_assignment?(node)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/self_assignment.rb', line 77



def multiple_self_assignment?(node)
  lhs, rhs = *node
  return false unless rhs.array_type?
  return false unless lhs.children.size == rhs.children.size

  lhs.children.zip(rhs.children).all? do |lhs_item, rhs_item|
    rhs_matches_lhs?(rhs_item, lhs_item)
  end
end


  








  

    #on_and_asgn(node)  
  



  

    


Alias for #on_or_asgn.



  



  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/self_assignment.rb', line 73



alias on_and_asgn on_or_asgn


  








  

    #on_casgn(node)  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/self_assignment.rb', line 57



def on_casgn(node)
  lhs_scope, lhs_name, rhs = *node
  return unless rhs&.const_type?

  rhs_scope, rhs_name = *rhs
  add_offense(node) if lhs_scope == rhs_scope && lhs_name == rhs_name
end


  








  

    #on_csend(node)  
  



  

    


Alias for #on_send.



  



  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/self_assignment.rb', line 43



alias on_csend on_send


  








  

    #on_cvasgn(node)  
  



  

    


Alias for #on_lvasgn.



  



  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/self_assignment.rb', line 54



alias on_cvasgn on_lvasgn


  








  

    #on_gvasgn(node)  
  



  

    


Alias for #on_lvasgn.



  



  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/self_assignment.rb', line 55



alias on_gvasgn on_lvasgn


  








  

    #on_ivasgn(node)  
  



  

    


Alias for #on_lvasgn.



  



  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/self_assignment.rb', line 53



alias on_ivasgn on_lvasgn


  








  

    #on_lvasgn(node)  
    Also known as: #on_ivasgn, #on_cvasgn, #on_gvasgn
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/self_assignment.rb', line 45



def on_lvasgn(node)
  lhs, rhs = *node
  return unless rhs

  rhs_type = ASSIGNMENT_TYPE_TO_RHS_TYPE[node.type]

  add_offense(node) if rhs.type == rhs_type && rhs.source == lhs.to_s
end


  








  

    #on_masgn(node)  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/self_assignment.rb', line 65



def on_masgn(node)
  add_offense(node) if multiple_self_assignment?(node)
end


  








  

    #on_or_asgn(node)  
    Also known as: #on_and_asgn
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/self_assignment.rb', line 69



def on_or_asgn(node)
  lhs, rhs = *node
  add_offense(node) if rhs_matches_lhs?(rhs, lhs)
end


  








  

    #on_send(node)  
    Also known as: #on_csend
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/self_assignment.rb', line 36



def on_send(node)
  if node.method?(:[]=)
    handle_key_assignment(node) if node.arguments.size == 2
  elsif node.assignment_method?
    handle_attribute_assignment(node) if node.arguments.size == 1
  end
end


  








  

    #rhs_matches_lhs?(rhs, lhs)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/self_assignment.rb', line 87



def rhs_matches_lhs?(rhs, lhs)
  rhs.type == ASSIGNMENT_TYPE_TO_RHS_TYPE[lhs.type] &&
    rhs.children.first == lhs.children.first
end