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Class: RuboCop::Cop::Style::SingleLineMethods

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/single_line_methods.rb

Overview

Checks for single-line method definitions that contain a body. It will accept single-line methods with no body.

Endless methods added in Ruby 3.0 are also accepted by this cop.

If Style/EndlessMethod is enabled with EnforcedStyle: allow_single_line or allow_always, single-line methods will be autocorrected to endless methods if there is only one statement in the body.

Examples:

# bad
def some_method; body end
def link_to(url); {:name => url}; end
def @table.columns; super; end

# good
def self.resource_class=(klass); end
def @table.columns; end
def some_method() = body

AllowIfMethodIsEmpty: true (default)

# good
def no_op; end

AllowIfMethodIsEmpty: false

# bad
def no_op; end

Constant Summary

::RuboCop::Cop::Base - Inherited

EMPTY_OFFENSES, RESTRICT_ON_SEND

::RuboCop::Cop::Alignment - Included

SPACE

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::Alignment - 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 Attribute Details

#allow_empty?Boolean (readonly, private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/single_line_methods.rb', line 60

def allow_empty?
  cop_config['AllowIfMethodIsEmpty']
end

#disallow_endless_method_style?Boolean (readonly, private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/single_line_methods.rb', line 136

def disallow_endless_method_style?
  endless_method_config = config.for_cop('Style/EndlessMethod')
  return true unless endless_method_config['Enabled']

  endless_method_config['EnforcedStyle'] == 'disallow'
end

Instance Method Details

#autocorrect(corrector, node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/single_line_methods.rb', line 52

def autocorrect(corrector, node)
  if correct_to_endless?(node.body)
    correct_to_endless(corrector, node)
  else
    correct_to_multiline(corrector, node)
  end
end

#break_line_before(corrector, node, range, indent_steps: 1) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/single_line_methods.rb', line 97

def break_line_before(corrector, node, range, indent_steps: 1)
  LineBreakCorrector.break_line_before(
    range: range, node: node, corrector: corrector,
    configured_width: configured_indentation_width, indent_steps: indent_steps
  )
end

#correct_to_endless(corrector, node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/single_line_methods.rb', line 88

def correct_to_endless(corrector, node)
  self_receiver = node.self_receiver? ? 'self.' : ''
  arguments = node.arguments.any? ? node.arguments.source : '()'
  body_source = method_body_source(node.body)
  replacement = "def #{self_receiver}#{node.method_name}#{arguments} = #{body_source}"

  corrector.replace(node, replacement)
end

#correct_to_endless?(body_node) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/single_line_methods.rb', line 64

def correct_to_endless?(body_node)
  return false if target_ruby_version < 3.0
  return false if disallow_endless_method_style?
  return false unless body_node
  return false if body_node.parent.assignment_method? ||
                  NOT_SUPPORTED_ENDLESS_METHOD_BODY_TYPES.include?(body_node.type)

  !(body_node.begin_type? || body_node.kwbegin_type?)
end

#correct_to_multiline(corrector, node) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/single_line_methods.rb', line 74

def correct_to_multiline(corrector, node)
  if (body = node.body) && body.begin_type? && body.parenthesized_call?
    break_line_before(corrector, node, body)
  else
    each_part(body) do |part|
      break_line_before(corrector, node, part)
    end
  end

  break_line_before(corrector, node, node.loc.end, indent_steps: 0)

  move_comment(node, corrector)
end

#each_part(body) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/single_line_methods.rb', line 104

def each_part(body)
  return unless body

  if body.begin_type?
    body.each_child_node { |part| yield part.source_range }
  else
    yield body.source_range
  end
end

#method_body_source(method_body) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/single_line_methods.rb', line 121

def method_body_source(method_body)
  if require_parentheses?(method_body)
    arguments_source = method_body.arguments.map(&:source).join(', ')
    body_source = "#{method_body.method_name}(#{arguments_source})"

    method_body.receiver ? "#{method_body.receiver.source}.#{body_source}" : body_source
  else
    method_body.source
  end
end

#move_comment(node, corrector) (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/single_line_methods.rb', line 114

def move_comment(node, corrector)
  LineBreakCorrector.move_comment(
    eol_comment: processed_source.comment_at_line(node.source_range.line),
    node: node, corrector: corrector
  )
end

#on_def(node) Also known as: #on_defs

[ GitHub ]

  
# File 'lib/rubocop/cop/style/single_line_methods.rb', line 41

def on_def(node)
  return unless node.single_line?
  return if node.endless?
  return if allow_empty? && !node.body

  add_offense(node) { |corrector| autocorrect(corrector, node) }
end

#on_defs(node)

Alias for #on_def.

[ GitHub ]

  
# File 'lib/rubocop/cop/style/single_line_methods.rb', line 48

alias on_defs on_def

#require_parentheses?(method_body) ⇒ Boolean (private)

[ GitHub ]

  
# File 'lib/rubocop/cop/style/single_line_methods.rb', line 132

def require_parentheses?(method_body)
  method_body.send_type? && !method_body.arguments.empty? && !method_body.comparison_method?
end