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Class: RuboCop::Cop::Style::LineEndConcatenation

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:
self, ::RuboCop::Cop::RangeHelp, ::RuboCop::Cop::Base, ::RuboCop::Cop::AutocorrectLogic, ::RuboCop::Cop::IgnoredNode, ::RuboCop::Util, RuboCop::AST::Sexp
Inherits: RuboCop::Cop::Base
Defined in: lib/rubocop/cop/style/line_end_concatenation.rb

Overview

Checks for string literal concatenation at the end of a line.

Examples:

# bad
some_str = 'ala' +
           'bala'

some_str = 'ala' <<
           'bala'

# good
some_str = 'ala' \
           'bala'

Cop Safety Information:

  • This cop is unsafe because it cannot be guaranteed that the receiver is a string, in which case replacing << with \ would result in a syntax error.

    For example, this would be a false positive:

    array << 'foo' <<
         'bar' <<
         'baz'

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

support_autocorrect?

::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::RangeHelp - Included

#add_range,
#arguments_range

A range containing the first to the last argument of a method call or method definition.
#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_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, #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

Class Method Details

.autocorrect_incompatible_with

[ GitHub ] 

  


# File 'lib/rubocop/cop/style/line_end_concatenation.rb', line 47



def self.autocorrect_incompatible_with
  [Style::RedundantInterpolation]
end


  







Instance Method Details



  

    #autocorrect(corrector, operator_range)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/line_end_concatenation.rb', line 80



def autocorrect(corrector, operator_range)
  # Include any trailing whitespace so we don't create a syntax error.
  operator_range = range_with_surrounding_space(operator_range,
                                                side: :right,
                                                newlines: false)
  one_more_char = operator_range.resize(operator_range.size + 1)
  # Don't create a double backslash at the end of the line, in case
  # there already was a backslash after the concatenation operator.
  operator_range = one_more_char if one_more_char.source.end_with?('\\')

  corrector.replace(operator_range, '\\')
end


  








  

    #check_token_set(index)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/line_end_concatenation.rb', line 57



def check_token_set(index)
  tokens = processed_source.tokens
  predecessor = tokens[index]
  operator = tokens[index + 1]
  successor = tokens[index + 2]

  return unless eligible_token_set?(predecessor, operator, successor)
  return if same_line?(operator, successor)

  next_successor = token_after_last_string(successor, index)
  return unless eligible_next_successor?(next_successor)

  register_offense(operator)
end


  








  

    #eligible_next_successor?(next_successor)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


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



def eligible_next_successor?(next_successor)
  !(next_successor && HIGH_PRECEDENCE_OP_TOKEN_TYPES.include?(next_successor.type))
end


  








  

    #eligible_operator?(operator)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/line_end_concatenation.rb', line 103



def eligible_operator?(operator)
  CONCAT_TOKEN_TYPES.include?(operator.type)
end


  








  

    #eligible_predecessor?(predecessor)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


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



def eligible_predecessor?(predecessor)
  standard_string_literal?(predecessor)
end


  








  

    #eligible_successor?(successor)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/line_end_concatenation.rb', line 99



def eligible_successor?(successor)
  successor && standard_string_literal?(successor)
end


  








  

    #eligible_token_set?(predecessor, operator, successor)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/line_end_concatenation.rb', line 93



def eligible_token_set?(predecessor, operator, successor)
  eligible_successor?(successor) &&
    eligible_operator?(operator) &&
    eligible_predecessor?(predecessor)
end


  








  

    #on_new_investigation  
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/line_end_concatenation.rb', line 51



def on_new_investigation
  processed_source.tokens.each_index { |index| check_token_set(index) }
end


  








  

    #register_offense(operator)   (private)
  

  [ GitHub ]


  

  


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



def register_offense(operator)
  message = format(MSG, operator: operator.text)

  add_offense(operator.pos, message: message) do |corrector|
    autocorrect(corrector, operator.pos)
  end
end


  








  

    #standard_string_literal?(token)  ⇒ Boolean  (private)
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/line_end_concatenation.rb', line 130



def standard_string_literal?(token)
  case token.type
  when SIMPLE_STRING_TOKEN_TYPE
    true
  when COMPLEX_STRING_BEGIN_TOKEN, COMPLEX_STRING_END_TOKEN
    QUOTE_DELIMITERS.include?(token.text)
  else
    false
  end
end


  








  

    #token_after_last_string(successor, base_index)   (private)
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/style/line_end_concatenation.rb', line 115



def token_after_last_string(successor, base_index)
  index = base_index + 3
  if successor.type == COMPLEX_STRING_BEGIN_TOKEN
    ends_to_find = 1
    while ends_to_find.positive?
      case processed_source.tokens[index].type
      when COMPLEX_STRING_BEGIN_TOKEN then ends_to_find += 1
      when COMPLEX_STRING_END_TOKEN then ends_to_find -= 1
      end
      index += 1
    end
  end
  processed_source.tokens[index]
end