Data in modules interpret nil as {}

class ntp (

  Optional[String] $ticker_file

) {

...

}

ntp::ticker_file: ~

% puppet lookup --explain --modulepath `pwd` ntp::ticker_file

Merge strategy first

  Data Binding "hiera"

    No such key: "ntp::ticker_file"

  Data Provider "EnvironmentDataProvider"

    No such key: "ntp::ticker_file"

  Module "ntp" using Data Provider "Hiera Data Provider, version 4"

    ConfigurationPath "/example/ntp/hiera.yaml"

    Merge strategy first

      Data Provider "OS family"

        Path "/example/ntp/data/os/RedHat.yaml"

          Original path: "os/%{facts.os.family}"

          Path not found

      Data Provider "defaults"

        Path "/example/ntp/data/defaults.yaml"

          Original path: "defaults"

          Found key: "ntp::ticker_file" value: {}

      Merged result: {}

  Merged result: {}

% /opt/puppetlabs/puppet/bin/ruby -r yaml -e 'p YAML.load(File.read("ntp/data/defaults.yaml"))["ntp::ticker_file"]'

nil

Error: Evaluation Error: Error while evaluating a Function Call, Class[Ntp]: parameter 'ticker_file' expects a String value, got Hash