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

Inherits:
Base
  • Object
show all
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

Constant Summary collapse

MSG = 
'$%<backref>s is out of range (%<count>s regexp capture %<group>s detected).'
REGEXP_RECEIVER_METHODS = 
%i[=~ === match].to_set.freeze
REGEXP_ARGUMENT_METHODS = 
%i[=~ match grep gsub gsub! sub sub! [] slice slice! index rindex
scan partition rpartition start_with? end_with?].to_set.freeze
REGEXP_CAPTURE_METHODS = 
(REGEXP_RECEIVER_METHODS + REGEXP_ARGUMENT_METHODS).freeze
RESTRICT_ON_SEND = 
REGEXP_CAPTURE_METHODS

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods inherited from Base

#active_support_extensions_enabled?, #add_global_offense, #add_offense, #always_autocorrect?, autocorrect_incompatible_with, badge, #begin_investigation, callbacks_needed, #callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?, #cop_config, cop_name, #cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, #inspect, joining_forces, lint?, match?, #message, #offenses, #on_investigation_end, #on_other_file, #parse, #parser_engine, #ready, #relevant_file?, requires_gem, #string_literals_frozen_by_default?, support_autocorrect?, support_multiple_source?, #target_rails_version, #target_ruby_version

Methods included from ExcludeLimit

#exclude_limit

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #autocorrect_with_disable_uncorrectable?, #correctable?, #disable_uncorrectable?, #safe_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

silence_warnings

Constructor Details

This class inherits a constructor from RuboCop::Cop::Base

Instance Method Details

#after_send(node) ⇒ Object 



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# 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

#on_in_pattern(node) ⇒ Object 



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# 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) ⇒ Object 



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# 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 ⇒ Object 



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# 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) ⇒ Object 



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# 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) ⇒ Object 



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# 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