This module is mixed in if layout conditions are provided. This means that if no layout conditions are used, this method is not used

Methods
C
Instance Public methods
conditional_layout?()

Determines whether the current action has a layout by checking the action name against the :only and :except conditions set on the layout.

Returns

  • Boolean - True if the action has a layout, false otherwise.

Source: show | on GitHub 

# File actionpack/lib/abstract_controller/layouts.rb, line 221
def conditional_layout?
  return unless super

  conditions = _layout_conditions

  if only = conditions[:only]
    only.include?(action_name)
  elsif except = conditions[:except]
    !except.include?(action_name)
  else
    true
  end
end