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Class: RuboCop::Cop::Lint::ConstantResolution

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::ProjectIndexHelp, ::RuboCop::Cop::Base, ::RuboCop::Cop::AutocorrectLogic, ::RuboCop::Cop::IgnoredNode, ::RuboCop::Util, RuboCop::AST::Sexp
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/lint/constant_resolution.rb

Overview

Checks that certain constants are fully qualified.

This is not enabled by default because it would mark a lot of offenses unnecessarily.

Generally, gems should fully qualify all constants to avoid conflicts with the code that uses the gem. Enable this cop without using Only/Ignore

Large projects will over time end up with one or two constant names that are problematic because of a conflict with a library or just internally using the same name for a namespace and a class. To avoid too many unnecessary offenses, enable this cop with Only: [The, Constant, Names, Causing, Issues]

Note
 Style/RedundantConstantBase cop is disabled if this cop is enabled, to prevent conflicting rules. This is because it respects user configurations that want to enable this cop which is disabled by default.

When AllCops/UseProjectIndex is enabled and the rubydex gem is installed, only genuinely ambiguous constants are reported: those that resolve to a different declaration through the surrounding nesting than they would fully qualified. This makes the cop practical to enable without Only/Ignore lists.

Examples:

# By default checks every constant

# bad
User

# bad
User::Login

# good
::User

# good
::User::Login

Only: ['Login']

# Restrict this cop to only being concerned about certain constants

# bad
Login

# good
::Login

# good
User::Login

Ignore: ['Login']

# Restrict this cop not being concerned about certain constants

# bad
User

# good
::User::Login

# good
Login

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

::RuboCop::Cop::ProjectIndexHelp - Included

BUILTIN_DOCUMENT_URI, FILE_URI_PREFIX, WINDOWS_DRIVE_PREFIX

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?

Instance Method Summary

::RuboCop::Cop::ProjectIndexHelp - Included

#external_dependency_checksum, #compute_project_index_signature,
#definitions_in_other_files

Returns the definitions among definitions that live in a file other than the one being inspected, ordered by path and line.
#indexed_singleton_member

A namespace without any singleton method has no singleton-class declaration of its own, so the lookup starts from the first ancestor that has one; its find_member covers the rest of the chain.
#indexed_singleton_of

The declaration of `declaration’s singleton class, or nil when no singleton method is defined on it anywhere in the project.
#inherited_index_member?

Whether an ancestor of scope other than scope itself defines member_name.
#lexical_nesting_of

The lexical nesting the node’s constants resolve through, outermost first.
#prior_definition_in_other_file, #project_index_signature,
#resolve_constant_in_index

Resolves a constant node the way Ruby does: the first segment through the lexical nesting and every following segment inside the previous one.
#same_file?

::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, #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, #matches_absolute_include_pattern?, #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, #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

#allowed_names (private)

[ GitHub ] 

  


# File 'lib/rubocop/cop/lint/constant_resolution.rb', line 108



def allowed_names
  cop_config['Only']
end


  








  

    #ambiguous_resolution?(node)  ⇒ Boolean  (private)
  



  

    


When AllCops/UseProjectIndex is enabled, only genuinely ambiguous
references are reported: the constant resolves to a different
declaration through the lexical nesting than it would fully
qualified. Names that resolve identically either way, or that the
index cannot resolve at all (e.g. constants from gems), are not
reported.



  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/constant_resolution.rb', line 93



def ambiguous_resolution?(node)
  name = node.short_name.to_s
  relative = project_index.resolve_constant(name, lexical_nesting_of(node))
  absolute = project_index.resolve_constant(name, [])

  !relative.nil? && !absolute.nil? && relative.name != absolute.name
rescue StandardError
  false
end


  








  

    #const_name?(name)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


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



def const_name?(name)
  name = name.to_s
  (allowed_names.empty? || allowed_names.include?(name)) && !ignored_names.include?(name)
end


  








  

    #ignored_names   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/constant_resolution.rb', line 112



def ignored_names
  cop_config['Ignore']
end


  








  

    #on_const(node)  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/constant_resolution.rb', line 78



def on_const(node)
  return if !unqualified_const?(node) || node.parent&.defined_module || node.loc.nil?
  return if project_index && !ambiguous_resolution?(node)

  add_offense(node)
end


  








  

    #unqualified_const?(node)  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/constant_resolution.rb', line 74



def_node_matcher :unqualified_const?, <<~PATTERN
  (const nil? #const_name?)
PATTERN