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Class: RuboCop::Cop::Style::RedundantStringEscape

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_string_escape.rb

Overview

Checks for redundant escapes in string literals.

Examples:

# bad - no need to escape # without following {/$/@
"\#foo"

# bad - no need to escape single quotes inside double quoted string
"\'foo\'"

# bad - heredocs are also checked for unnecessary escapes
<<~STR
  \#foo \"foo\"
STR

# good
"#foo"

# good
"\#{no_interpolation}"

# good
"'foo'"

# good
"foo\
bar"

# good
<<~STR
  #foo "foo"
STR

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

::RuboCop::Cop::RangeHelp - Included

BYTE_ORDER_MARK, NOT_GIVEN

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::MatchRange - Included

#each_match_range

Return a new Range covering the first matching group number for each match of regex inside range.

#match_range

For a match inside range, return a new Range covering the match.

::RuboCop::Cop::RangeHelp - Included

#add_range, #column_offset_between,
#contents_range

A range containing only the contents of a literal with delimiters (e.g.

#directions,
#effective_column

Returns the column attribute of the range, except if the range is on the first line and there’s a byte order mark at the beginning of that line, in which case 1 is subtracted from the column value.

#final_pos, #move_pos, #move_pos_str, #range_between, #range_by_whole_lines, #range_with_comments, #range_with_comments_and_lines, #range_with_surrounding_comma, #range_with_surrounding_space, #source_range

::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

#allowed_escape?(node, range) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_string_escape.rb', line 79

def allowed_escape?(node, range)
  escaped = range.source[(1..-1)]

  # Inside a single-quoted string, escapes (except \\ and \') do not have special meaning,
  # and so are not redundant, as they are a literal backslash.
  return true if interpolation_not_enabled?(node)

  # Strictly speaking a few single-letter chars are currently unnecessary to "escape", e.g.
  # d, but enumerating them is rather difficult, and their behavior could change over time
  # with different versions of Ruby so that e.g. /\d/ != /d/
  return true if /[\n\\[[:alnum:]]]/.match?(escaped[0])

  return true if escaped[0] == ' ' && (percent_array_literal?(node) || node.heredoc?)

  return true if disabling_interpolation?(range)
  return true if delimiter?(node, escaped[0])

  false
end

#array_literal?(node, prefix) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_string_escape.rb', line 119

def array_literal?(node, prefix)
  if literal_in_interpolated_or_multiline_string?(node)
    array_literal?(node.parent, prefix)
  else
    node.parent&.array_type? && node.parent.source.start_with?(prefix)
  end
end

#begin_loc_present?(node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_string_escape.rb', line 73

def begin_loc_present?(node)
  # e.g. a __FILE__ literal has no begin loc so we can't query if it's nil
  node.loc.to_hash.key?(:begin) && !node.loc.begin.nil?
end

#delimiter?(node, char) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_string_escape.rb', line 153

def delimiter?(node, char)
  return false if heredoc?(node)

  if literal_in_interpolated_or_multiline_string?(node) || percent_array_literal?(node)
    return delimiter?(node.parent, char)
  end

  return true unless node.loc.begin

  delimiters = [node.loc.begin.source[-1], node.loc.end.source[0]]

  delimiters.include?(char)
end

#disabling_interpolation?(range) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_string_escape.rb', line 171

def disabling_interpolation?(range)
  # Allow \#{foo}, \#$foo, \#@foo, and \#@@foo
  # for escaping local, global, instance and class variable interpolations
  return true if range.source.match?(/\A\\#[{$@]/)
  # Also allow #\{foo}, #\$foo, #\@foo and #\@@foo
  return true if range.adjust(begin_pos: -2).source.match?(/\A[^\\]#\\[{$@]/)
  # For `\#\{foo} allow `\#` and warn `\{`
  return true if range.adjust(end_pos: 1).source == '\\#\\{'

  false
end

#heredoc?(node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_string_escape.rb', line 149

def heredoc?(node)
  (node.str_type? || node.dstr_type?) && node.heredoc?
end

#heredoc_with_disabled_interpolation?(node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_string_escape.rb', line 139

def heredoc_with_disabled_interpolation?(node)
  if heredoc?(node)
    node.source.end_with?("'")
  elsif node.parent&.dstr_type?
    heredoc_with_disabled_interpolation?(node.parent)
  else
    false
  end
end

#interpolation_not_enabled?(node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_string_escape.rb', line 100

def interpolation_not_enabled?(node)
  single_quoted?(node) ||
    percent_w_literal?(node) ||
    percent_q_literal?(node) ||
    heredoc_with_disabled_interpolation?(node)
end

#literal_in_interpolated_or_multiline_string?(node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_string_escape.rb', line 167

def literal_in_interpolated_or_multiline_string?(node)
  node.str_type? && !begin_loc_present?(node) && node.parent&.dstr_type?
end

#message(range) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_string_escape.rb', line 59

def message(range)
  format(MSG, char: range.source[-1])
end

#on_str(node)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_string_escape.rb', line 43

def on_str(node)
  return if node.parent&.regexp_type? || node.parent&.xstr_type? || node.character_literal?

  str_contents_range = str_contents_range(node)

  each_match_range(str_contents_range, /(\\.)/) do |range|
    next if allowed_escape?(node, range.resize(3))

    add_offense(range) do |corrector|
      corrector.remove_leading(range, 1)
    end
  end
end

#percent_array_literal?(node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_string_escape.rb', line 135

def percent_array_literal?(node)
  percent_w_literal?(node) || percent_w_upper_literal?(node)
end

#percent_q_literal?(node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_string_escape.rb', line 111

def percent_q_literal?(node)
  if literal_in_interpolated_or_multiline_string?(node)
    percent_q_literal?(node.parent)
  else
    node.source.start_with?('%q')
  end
end

#percent_w_literal?(node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_string_escape.rb', line 127

def percent_w_literal?(node)
  array_literal?(node, '%w')
end

#percent_w_upper_literal?(node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_string_escape.rb', line 131

def percent_w_upper_literal?(node)
  array_literal?(node, '%W')
end

#single_quoted?(node) ⇒ Boolean (private)

[ GitHub ]

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

def single_quoted?(node)
  delimiter?(node, "'")
end

#str_contents_range(node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/redundant_string_escape.rb', line 63

def str_contents_range(node)
  if heredoc?(node)
    node.loc.heredoc_body
  elsif node.str_type?
    node.source_range
  elsif begin_loc_present?(node)
    contents_range(node)
  end
end