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Class: RuboCop::Cop::Style::RedundantRegexpCharacterClass

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:
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/style/redundant_regexp_character_class.rb

Overview

Checks for unnecessary single-element Regexp character classes.

Examples:

# bad
r = /[x]/

# good
r = /x/

# bad
r = /[\s]/

# good
r = /\s/

# bad
r = %r{/[b]}

# good
r = %r{/b}

# good
r = /[ab]/

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

Class Attribute Summary

::RuboCop::Cop::AutoCorrector - Extended

::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 an 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

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

::RuboCop::Cop::IgnoredNode - Included

Constructor Details

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

Instance Method Details

#backslash_b?(elem) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_regexp_character_class.rb', line 101

def backslash_b?(elem)
  # \b's behavior is different inside and outside of a character class, matching word
  # boundaries outside but backspace (0x08) when inside.
  elem == '\b'
end

#each_redundant_character_class(node) (private)

[ GitHub ]

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

def each_redundant_character_class(node)
  each_single_element_character_class(node) do |char_class|
    next unless redundant_single_element_character_class?(node, char_class)

    yield char_class.loc.body
  end
end

#each_single_element_character_class(node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_regexp_character_class.rb', line 61

def each_single_element_character_class(node)
  node.parsed_tree&.each_expression do |expr|
    next if expr.type != :set || expr.expressions.size != 1
    next if expr.negative?
    next if %i[set posixclass nonposixclass].include?(expr.expressions.first.type)
    next if multiple_codepoints?(expr.expressions.first)

    yield expr
  end
end

#multiple_codepoints?(expression) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_regexp_character_class.rb', line 83

def multiple_codepoints?(expression)
  expression.respond_to?(:codepoints) && expression.codepoints.count >= 2
end

#octal_requiring_char_class?(elem) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_regexp_character_class.rb', line 107

def octal_requiring_char_class?(elem)
  # The octal escapes \1 to \7 only work inside a character class
  # because they would be a backreference outside it.
  elem.match?(/\A\\[1-7]\z/)
end

#on_regexp(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_regexp_character_class.rb', line 37

def on_regexp(node)
  each_redundant_character_class(node) do |loc|
    add_offense(
      loc, message: format(
        MSG_REDUNDANT_CHARACTER_CLASS,
        char_class: loc.source,
        element: without_character_class(loc)
      )
    ) do |corrector|
      corrector.replace(loc, without_character_class(loc))
    end
  end
end

#redundant_single_element_character_class?(node, char_class) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_regexp_character_class.rb', line 72

def redundant_single_element_character_class?(node, char_class)
  class_elem = char_class.expressions.first.text

  non_redundant =
    whitespace_in_free_space_mode?(node, class_elem) ||
    backslash_b?(class_elem) || octal_requiring_char_class?(class_elem) ||
    requires_escape_outside_char_class?(class_elem)

  !non_redundant
end

#requires_escape_outside_char_class?(elem) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_regexp_character_class.rb', line 113

def requires_escape_outside_char_class?(elem)
  REQUIRES_ESCAPE_OUTSIDE_CHAR_CLASS_CHARS.include?(elem)
end

#whitespace_in_free_space_mode?(node, elem) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_regexp_character_class.rb', line 95

def whitespace_in_free_space_mode?(node, elem)
  return false unless node.extended?

  /\s/.match?(elem)
end

#without_character_class(loc) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_regexp_character_class.rb', line 87

def without_character_class(loc)
  without_character_class = loc.source[1..-2]

  # Adds `\` to prevent autocorrection that changes to an interpolated string when `[#]`.
  # e.g. From `/[#]{0}/` to `/#{0}/`
  loc.source == '[#]' ? "\\#{without_character_class}" : without_character_class
end