Broken facter plugin

bad.rb

# This is a horrible thing
# Kinda (mostly) figures out the server type from the hostname
Facter.add("servertype") do
  setcode do
    hostname = Facter.value('hostname')

    if hostname.include?('-')
      hostname_parts = hostname.split("-", 0)
      hostname_parts[0].downcase
    elsif hostname =~ /^ns/
      "ns"
    else
      "other"
    end
  end
end

#### Throws:
# Error: Could not retrieve catalog from remote server: Error 400 on SERVER: Evaluation Error: Error while evaluating a Function Call, Error from DataBinding 'hiera' while looking up 'rsyslog::modules': undefined method `empty?' for nil:NilClass at /etc/puppet/environments/production/modules/rc/manifests/base.pp:2:1 on node puppet-04.*******************
# Warning: Not using cache on failed catalog
# Error: Could not retrieve catalog; skipping run

good.rb

# This is a horrible thing
# Kinda (mostly) figures out the server type from the hostname
Facter.add("servertype") do
  setcode do
    hostname = Facter.value('hostname')

    if hostname.include?('-')
      hostname_parts = hostname.split("-", 0)
      hostname_parts[0].upcase
    elsif hostname =~ /^ns/
      "ns"
    else
      "other"
    end
  end
end