2.7.19

notice: Scope(Class[main]): Puppet version: 2.7.19
Must pass required to Class[Bar] at line 9 on node dcarley-mba.local

3.0.2

Notice: Scope(Class[main]): Puppet version: 3.0.2
Warning: Config file /etc/puppet/hiera.yaml not found, using Hiera defaults
Notice:
Notice: /Stage[main]/Bar/Notify[should never be empty]/message: defined 'message' as ''
Notice: Finished catalog run in 0.14 seconds

3.2.2

Notice: Scope(Class[main]): Puppet version: 3.2.2
Warning: Config file /Users/dcarley/.puppet/hiera.yaml not found, using Hiera defaults
Notice:
Notice: /Stage[main]/Bar/Notify[should never be empty]/message: defined 'message' as ''
Notice: Finished catalog run in 0.06 seconds

param_test.pp

class foo (
  $required = undef
) {
  class { 'bar':
    required => $required,
  }
}

class bar ($required) {
  notify { 'should never be empty':
    message => "${required}",
  }
}

notice("Puppet version: ${puppetversion}")
include foo