module Rake::Cloneable

def initialize_copy(source)

The hook that invoked by 'clone' and 'dup' methods.
def initialize_copy(source)
  super
  source.instance_variables.each do |var|
    src_value  = source.instance_variable_get(var)
    value = src_value.clone rescue src_value
    instance_variable_set(var, value)
  end
end