init.pp

# These two work fine with puppet apply non-root
#class foo ($message=hiera(message)) {
#class foo ($message='default') {

# Hiera Data bindings doesn't work with puppet apply root or non-root
class foo ($message) {

#class foo {
  #$message = hiera(message)
  #notify { "A message from foo via hiera databindings or class param default: $message": }
  notify { "A message from foo via hiera databindings or class param default: $message": }
}