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Class: RuboCop::Cop::Lint::UselessConstantScoping

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/useless_constant_scoping.rb

Overview

Checks for useless constant scoping. Private constants must be defined using private_constant. Even if private access modifier is used, it is public scope despite its appearance.

It does not support autocorrection due to behavior change and multiple ways to fix it. Or a public constant may be intended.

Constant assignments that define classes or modules via Class.new, Module.new, Struct.new, or Data.define are allowed. Those forms are class and module definitions written with assignment syntax, and match the common practice of placing nested class / module bodies after private without intending private constant visibility.

Examples:

# bad
class Foo
  private
  PRIVATE_CONST = 42
end

# good
class Foo
  PRIVATE_CONST = 42
  private_constant :PRIVATE_CONST
end

# good
class Foo
  PUBLIC_CONST = 42 # If private scope is not intended.
end

# good - class/module definitions via assignment, same as nested `class`/`module`
class Foo
  private

  def some_private_method
  end

  MyClass = Class.new
  MyModule = Module.new
  MyStruct = Struct.new(:name)
  MyData = Data.define(:name)
end

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.

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

Reserved for Commissioner.

::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, #project_index, #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?,
#skipped_unsafe_correction_with_disable_uncorrectable?

Whether a correction exists but is skipped because it is unsafe in a safe autocorrect run, while --disable-uncorrectable asks for a todo comment on everything this run cannot correct.

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_gem_version

Returns a gems locked versions (i.e.
#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, #covering_disabled_range, #current_corrector,
#current_offense_locations

Reserved for Commissioner:
#current_offenses, #currently_disabled_lines, #custom_severity, #default_severity, #disable_uncorrectable, #enabled_line?,
#enabled_lines?

A multi-line offense is suppressed by a directive on any line of its range, not only its first line, matching the intuition that the directive is attached to the offending code.
#file_name_matches_any?, #find_message, #find_severity, #matches_absolute_include_pattern?, #range_for_original, #range_from_node_or_range,
#reset_investigation

Actually private methods.
#suppression_reason

The -- reason on the directive that suppresses offenses on this range, or nil when the directive carries none.
#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, #eol_comment, #eol_comment_would_be_inside_literal?, #heredoc_range, #line_with_eol_comment_too_long?, #max_line_length, #multiline_ranges, #multiline_string?,
#range_by_lines

Expand the given range to include all of any lines it covers.
#range_of_first_line, #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

#after_private_modifier?(left_siblings) ⇒ Boolean (private)

[ GitHub ] 

  


# File 'lib/rubocop/cop/lint/useless_constant_scoping.rb', line 85



def after_private_modifier?(left_siblings)
  access_modifier_candidates = left_siblings.compact.select do |left_sibling|
    left_sibling.respond_to?(:bare_access_modifier?) && left_sibling.bare_access_modifier?
  end

  return false if access_modifier_candidates.empty?

  access_modifier_candidates.last.command?(:private)
end


  








  

    #class_or_module_definition_assignment?(node)  
  



  

    


Matches class/module-like constant assignments. Nested class / module
keyword definitions are not visited by this cop; these assignment forms are
the equivalent syntax and should be treated the same way.



  



  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/useless_constant_scoping.rb', line 62



def_node_matcher :class_or_module_definition_assignment?, <<~PATTERN
  {
    (send (const {nil? cbase} {:Class :Module :Struct}) :new ...)
    (send (const {nil? cbase} :Data) :define ...)
    (any_block
      {
        (send (const {nil? cbase} {:Class :Module :Struct}) :new ...)
        (send (const {nil? cbase} :Data) :define ...)
      }
      ...)
  }
PATTERN


  








  

    #on_casgn(node)  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/useless_constant_scoping.rb', line 75



def on_casgn(node)
  return unless after_private_modifier?(node.left_siblings)
  return if private_constantize?(node.right_siblings, node.name)
  return if class_or_module_definition_assignment?(node.expression)

  add_offense(node)
end


  








  

    #private_constantize?(right_siblings, const_value)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/useless_constant_scoping.rb', line 95



def private_constantize?(right_siblings, const_value)
  private_constant_arguments = right_siblings.map { |node| private_constants(node) }

  private_constant_values = private_constant_arguments.flatten.filter_map do |constant|
    constant.value.to_sym if constant.respond_to?(:value)
  end

  private_constant_values.include?(const_value)
end


  








  

    #private_constants(node)  
  

  [ GitHub ]


  

  


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



def_node_matcher :private_constants, <<~PATTERN
  (send nil? :private_constant $...)
PATTERN