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Class: RuboCop::Cop::Layout::TrailingEmptyLines

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/layout/trailing_empty_lines.rb

Overview

Looks for trailing blank lines and a final newline in the source code.

Examples:

EnforcedStyle: final_newline (default)

# `final_newline` looks for one newline at the end of files.

# bad
class Foo; end

# EOF

# bad
class Foo; end # EOF

# good
class Foo; end
# EOF

EnforcedStyle: final_blank_line

# `final_blank_line` looks for one blank line followed by a new line
# at the end of files.

# bad
class Foo; end
# EOF

# bad
class Foo; end # EOF

# good
class Foo; end

# EOF

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

::RuboCop::Cop::ConfigurableEnforcedStyle - Included

SYMBOL_TO_STRING_CACHE

::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::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::ConfigurableEnforcedStyle - Included

::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

#end_with_percent_blank_string?(processed_source) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/layout/trailing_empty_lines.rb', line 90

def end_with_percent_blank_string?(processed_source)
  processed_source.buffer.source.end_with?("%\n\n")
end

#ends_in_end?(processed_source) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/layout/trailing_empty_lines.rb', line 80

def ends_in_end?(processed_source)
  buffer = processed_source.buffer

  return true if buffer.source.match?(/\s*__END__/)
  return false if processed_source.tokens.empty?

  extra = buffer.source[processed_source.tokens.last.end_pos..]
  extra&.strip&.start_with?('__END__')
end

#message(wanted_blank_lines, blank_lines) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/layout/trailing_empty_lines.rb', line 94

def message(wanted_blank_lines, blank_lines)
  case blank_lines
  when -1
    'Final newline missing.'
  when 0
    'Trailing blank line missing.'
  else
    instead_of = if wanted_blank_lines.zero?
                   ''
                 else
                   "instead of #{wanted_blank_lines} "
                 end
    format('%<current>d trailing blank lines %<prefer>sdetected.',
           current: blank_lines, prefer: instead_of)
  end
end

#offense_detected(buffer, wanted_blank_lines, blank_lines, whitespace_at_end) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/layout/trailing_empty_lines.rb', line 67

def offense_detected(buffer, wanted_blank_lines, blank_lines, whitespace_at_end)
  begin_pos = buffer.source.length - whitespace_at_end.length
  autocorrect_range = range_between(begin_pos, buffer.source.length)
  begin_pos += 1 unless whitespace_at_end.empty?
  report_range = range_between(begin_pos, buffer.source.length)

  add_offense(
    report_range, message: message(wanted_blank_lines, blank_lines)
  ) do |corrector|
    corrector.replace(autocorrect_range, style == :final_newline ? "\n" : "\n\n")
  end
end

#on_new_investigation

[ GitHub ]

  
# File 'lib/rubocop/cop/layout/trailing_empty_lines.rb', line 45

def on_new_investigation
  buffer = processed_source.buffer
  return if buffer.source.empty?

  # The extra text that comes after the last token could be __END__
  # followed by some data to read. If so, we don't check it because
  # there could be good reasons why it needs to end with a certain
  # number of newlines.
  return if ends_in_end?(processed_source)
  return if end_with_percent_blank_string?(processed_source)

  whitespace_at_end = buffer.source[/\s*\Z/]
  blank_lines = whitespace_at_end.count("\n") - 1
  wanted_blank_lines = style == :final_newline ? 0 : 1

  return unless blank_lines != wanted_blank_lines

  offense_detected(buffer, wanted_blank_lines, blank_lines, whitespace_at_end)
end