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Class: RuboCop::Cop::Style::RedundantSelfAssignmentBranch

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

Overview

Checks for places where conditional branch makes redundant self-assignment.

It only detects local variable because it may replace state of instance variable, class variable, and global variable that have state across methods with nil.

Examples:

# bad
foo = condition ? bar : foo

# good
foo = bar if condition

# bad
foo = condition ? foo : bar

# good
foo = bar unless condition

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

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::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::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

#bad_method?(node)

[ GitHub ] 

  


# File 'lib/rubocop/cop/style/redundant_self_assignment_branch.rb', line 31



def_node_matcher :bad_method?, <<~PATTERN
  (send nil? :bad_method ...)
PATTERN


  








  

    #inconvertible_to_modifier?(if_branch, else_branch)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_self_assignment_branch.rb', line 59



def inconvertible_to_modifier?(if_branch, else_branch)
  multiple_statements?(if_branch) || multiple_statements?(else_branch) ||
    (else_branch.respond_to?(:elsif?) && else_branch.elsif?)
end


  








  

    #multiple_statements?(branch)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_self_assignment_branch.rb', line 64



def multiple_statements?(branch)
  return false unless branch&.begin_type?

  !branch.children.empty?
end


  








  

    #on_lvasgn(node)  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_self_assignment_branch.rb', line 35



def on_lvasgn(node)
  expression = node.expression

  return unless use_if_and_else_branch?(expression)

  if_branch = expression.if_branch
  else_branch = expression.else_branch
  return if inconvertible_to_modifier?(if_branch, else_branch)

  if self_assign?(node.name, if_branch)
    register_offense(expression, if_branch, else_branch, 'unless')
  elsif self_assign?(node.name, else_branch)
    register_offense(expression, else_branch, if_branch, 'if')
  end
end


  








  

    #register_offense(if_node, offense_branch, opposite_branch, keyword)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_self_assignment_branch.rb', line 74



def register_offense(if_node, offense_branch, opposite_branch, keyword)
  add_offense(offense_branch) do |corrector|
    assignment_value = opposite_branch ? opposite_branch.source : 'nil'
    replacement = "#{assignment_value} #{keyword} #{if_node.condition.source}"
    if opposite_branch.respond_to?(:heredoc?) && opposite_branch.heredoc?
      replacement += opposite_branch.loc.heredoc_end.with(
        begin_pos: opposite_branch.source_range.end_pos
      ).source
    end

    corrector.replace(if_node, replacement)
  end
end


  








  

    #self_assign?(variable, branch)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_self_assignment_branch.rb', line 70



def self_assign?(variable, branch)
  variable.to_s == branch&.source
end


  








  

    #use_if_and_else_branch?(expression)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/redundant_self_assignment_branch.rb', line 53



def use_if_and_else_branch?(expression)
  return false unless expression&.if_type?

  !expression.ternary? || !expression.else?
end