Class: RuboCop::Cop::Style::RedundantLineContinuation

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Includes:
MatchRange, ReparsedEquivalence
Defined in:
lib/rubocop/cop/style/redundant_line_continuation.rb

Overview

Checks for redundant line continuation.

A line continuation is redundant when removing the backslash does not change how the program parses: the source is reparsed without the backslash and the resulting AST is compared to the original. Only backslashes that are pure noise are reported; backslashes that are significant — inside strings, for string concatenation, before an operator or argument that would otherwise start a new statement, and so on — are left alone, as are backslashes in comments.

Examples:

# bad
foo. \
  bar
foo \
  &.bar \
    .baz

# good
foo.
  bar
foo
  &.bar
    .baz

# bad
[foo, \
  bar]
{foo: \
  bar}

# good
[foo,
  bar]
{foo:
  bar}

# bad
foo(bar, \
  baz)

# good
foo(bar,
  baz)

# also good - backslash in string concatenation is not redundant
foo('bar' \
  'baz')

# also good - backslash at the end of a comment is not redundant
foo(bar, # \
  baz)

# also good - backslash at the line following the newline begins with a + or -,
# it is not redundant
1 \
  + 2 \
    - 3

# also good - backslash with newline between the method name and its arguments,
# it is not redundant.
some_method \
  (argument)

Constant Summary collapse

MSG = 
'Redundant line continuation.'
LINE_CONTINUATION = 
'\\'
LINE_CONTINUATION_PATTERN = 
/(\\\n)/.freeze
STRING_TOKEN_TYPES = 
%i[tSTRING tSTRING_CONTENT].freeze
STRING_LITERAL_ENDING_TOKEN_TYPES = 
%i[tSTRING tSTRING_END].freeze
STRING_LITERAL_BEGINNING_TOKEN_TYPES = 
%i[tSTRING tSTRING_BEG].freeze

Constants included from ReparsedEquivalence

ReparsedEquivalence::MAX_VERIFICATION_FRAGMENT_SIZE

Constants included from RangeHelp

RangeHelp::BYTE_ORDER_MARK, RangeHelp::NOT_GIVEN

Constants inherited from Base

Base::RESTRICT_ON_SEND

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source, #project_index

Instance Method Summary collapse

Methods included from AutoCorrector

support_autocorrect?

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_gem_version, #target_rails_version, #target_ruby_version

Methods included from ExcludeLimit

cop_dir_for, #exclude_limit, read_limits

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

#on_new_investigation ⇒ Object 



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# File 'lib/rubocop/cop/style/redundant_line_continuation.rb', line 82

def on_new_investigation
  return unless processed_source.ast

  # A backslash is redundant if the source parses to the same AST
  # without it; verification is the offense logic itself, so oversized
  # scopes are reparsed regardless of size.
  verified_by_reparse(line_continuation_candidates, oversized: :verify).each do |range|
    add_offense(range) do |corrector|
      corrector.remove_leading(range, 1)
    end
  end

  inspect_end_of_ruby_code_line_continuation
end