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Class: RuboCop::Cop::Lint::OutOfRangeRegexpRef

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/out_of_range_regexp_ref.rb

Overview

Looks for references of Regexp captures that are out of range and thus always returns nil.

Examples:

/(foo)bar/ =~ 'foobar'

# bad - always returns nil

puts $2 # => nil

# good

puts $1 # => foo

Cop Safety Information:

  • This cop is unsafe because it is naive in how it determines what references are available based on the last encountered regexp, but it cannot handle some cases, such as conditional regexp matches, which leads to false positives, such as:

    foo ? /(c)(b)/ =~ str : /(b)/ =~ str
do_something if $2
# $2 is defined for the first condition but not the second, however
# the cop will mark this as an offense.

    This might be a good indication of code that should be refactored, however.

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

::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_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, #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, #heredoc_range, #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, #range_overlaps_offense?, #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_send(node)

[ GitHub ] 

  


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



def after_send(node)
  @valid_ref = nil

  if regexp_first_argument?(node)
    check_regexp(node.first_argument)
  elsif regexp_receiver?(node)
    check_regexp(node.receiver)
  end
end


  








  

    #check_regexp(node)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/out_of_range_regexp_ref.rb', line 102



def check_regexp(node)
  return if node.interpolation?

  named_capture = node.each_capture(named: true).count
  @valid_ref = if named_capture.positive?
                 named_capture
               else
                 node.each_capture(named: false).count
               end
end


  








  

    #nth_ref_receiver?(send_node)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/out_of_range_regexp_ref.rb', line 122



def nth_ref_receiver?(send_node)
  send_node.receiver&.nth_ref_type?
end


  








  

    #on_in_pattern(node)  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/out_of_range_regexp_ref.rb', line 71



def on_in_pattern(node)
  regexp_patterns = regexp_patterns(node)

  @valid_ref = regexp_patterns.filter_map { |pattern| check_regexp(pattern) }.max
end


  








  

    #on_match_with_lvasgn(node)  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/out_of_range_regexp_ref.rb', line 51



def on_match_with_lvasgn(node)
  check_regexp(node.children.first)
end


  








  

    #on_new_investigation  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/out_of_range_regexp_ref.rb', line 47



def on_new_investigation
  @valid_ref = 0
end


  








  

    #on_nth_ref(node)  
  

  [ GitHub ]


  

  


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



def on_nth_ref(node)
  backref = node.children.first
  return if @valid_ref.nil? || backref <= @valid_ref

  message = format(
    MSG,
    backref: backref,
    count: @valid_ref.zero? ? 'no' : @valid_ref,
    group: @valid_ref == 1 ? 'group' : 'groups'
  )

  add_offense(node, message: message)
end


  








  

    #on_when(node)  
  

  [ GitHub ]


  

  


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



def on_when(node)
  regexp_conditions = node.conditions.select(&:regexp_type?)

  @valid_ref = regexp_conditions.filter_map { |condition| check_regexp(condition) }.max
end


  








  

    #regexp_first_argument?(send_node)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/out_of_range_regexp_ref.rb', line 113



def regexp_first_argument?(send_node)
  send_node.first_argument&.regexp_type? \
    && REGEXP_ARGUMENT_METHODS.include?(send_node.method_name)
end


  








  

    #regexp_patterns(in_node)   (private)
  

  [ GitHub ]


  

  


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



def regexp_patterns(in_node)
  pattern = in_node.pattern
  if pattern.regexp_type?
    [pattern]
  else
    pattern.each_descendant(:regexp).to_a
  end
end


  








  

    #regexp_receiver?(send_node)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/lint/out_of_range_regexp_ref.rb', line 118



def regexp_receiver?(send_node)
  send_node.receiver&.regexp_type?
end