class RuboCop::Cop::Style::ClassMethodsDefinitions

Enforces using ‘def self.method_name` or `class << self` to define class methods.

@example EnforcedStyle: def_self (default)

# bad
class SomeClass
  class << self
    attr_accessor :class_accessor

    def class_method
      # ...
    end
  end
end

# good
class SomeClass
  def self.class_method
    # ...
  end

  class << self
    attr_accessor :class_accessor
  end
end

# good - contains private method
class SomeClass
  class << self
    attr_accessor :class_accessor

    private

    def private_class_method
      # ...
    end
  end
end

@example EnforcedStyle: self_class

# bad
class SomeClass
  def self.class_method
    # ...
  end
end

# good
class SomeClass
  class << self
    def class_method
      # ...
    end
  end
end

Constants

MSG
MSG_SCLASS

Public Instance Methods

on_defs(node) click to toggle source
# File lib/rubocop/cop/style/class_methods_definitions.rb, line 81
def on_defs(node)
  return if def_self_style?
  return unless node.receiver.self_type?

  message = format(MSG, preferred: 'class << self')
  add_offense(node, message: message)
end
on_sclass(node) click to toggle source
# File lib/rubocop/cop/style/class_methods_definitions.rb, line 71
def on_sclass(node)
  return unless def_self_style?
  return unless node.identifier.self_type?
  return unless all_methods_public?(node)

  add_offense(node, message: MSG_SCLASS) do |corrector|
    autocorrect_sclass(node, corrector)
  end
end

Private Instance Methods

all_methods_public?(sclass_node) click to toggle source
# File lib/rubocop/cop/style/class_methods_definitions.rb, line 95
def all_methods_public?(sclass_node)
  def_nodes = def_nodes(sclass_node)
  return false if def_nodes.empty?

  def_nodes.all? { |def_node| node_visibility(def_node) == :public }
end
autocorrect_sclass(node, corrector) click to toggle source
# File lib/rubocop/cop/style/class_methods_definitions.rb, line 115
def autocorrect_sclass(node, corrector)
  rewritten_defs = []

  def_nodes(node).each do |def_node|
    next unless node_visibility(def_node) == :public

    range, source = extract_def_from_sclass(def_node, node)

    corrector.remove(range)
    rewritten_defs << source
  end

  if sclass_only_has_methods?(node)
    corrector.remove(node)
    rewritten_defs.first&.strip!
  else
    corrector.insert_after(node, "\n")
  end

  corrector.insert_after(node, rewritten_defs.join("\n"))
end
def_nodes(sclass_node) click to toggle source
# File lib/rubocop/cop/style/class_methods_definitions.rb, line 102
def def_nodes(sclass_node)
  sclass_def = sclass_node.body
  return [] unless sclass_def

  if sclass_def.def_type?
    [sclass_def]
  elsif sclass_def.begin_type?
    sclass_def.each_child_node(:def).to_a
  else
    []
  end
end
def_self_style?() click to toggle source
# File lib/rubocop/cop/style/class_methods_definitions.rb, line 91
def def_self_style?
  style == :def_self
end
extract_def_from_sclass(def_node, sclass_node) click to toggle source
# File lib/rubocop/cop/style/class_methods_definitions.rb, line 141
def extract_def_from_sclass(def_node, sclass_node)
  range = source_range_with_comment(def_node)
  source = range.source.sub!(
    "def #{def_node.method_name}",
    "def self.#{def_node.method_name}"
  )

  source = source.gsub(/^ {#{indentation_diff(def_node, sclass_node)}}/, '')
  [range, source.chomp]
end
indentation_diff(node1, node2) click to toggle source
# File lib/rubocop/cop/style/class_methods_definitions.rb, line 152
def indentation_diff(node1, node2)
  node1.loc.column - node2.loc.column
end
sclass_only_has_methods?(node) click to toggle source
# File lib/rubocop/cop/style/class_methods_definitions.rb, line 137
def sclass_only_has_methods?(node)
  node.body.def_type? || node.body.each_child_node.all?(&:def_type?)
end