class ActionDispatch::Session::SessionRestoreError

def initialize(const_error = nil)
  if const_error
    ActiveSupport::Deprecation.warn("Passing #original_exception is deprecated and has no effect. " \
                                    "Exceptions will automatically capture the original exception.", caller)
  end
  super("Session contains objects whose class definition isn't available.\n" +
    "Remember to require the classes for all objects kept in the session.\n" +
    "(Original exception: #{$!.message} [#{$!.class}])\n")
  set_backtrace $!.backtrace
end

def original_exception
  ActiveSupport::Deprecation.warn("#original_exception is deprecated. Use #cause instead.", caller)
  cause
end