[Puppet Users] install Rubygem-package on a machine without Rubygems preinstalled, "Provider gem is not functional on this host"

On a clean Debian system - without Rubygems installed - I want to install a
Rubygem package (ruby-ldap) with Puppet. So the package has "gem" as
package Provider.

This is my manifest so far (I kept it simple):

# test.pp
Package { ensure => 'installed' }

package {
'rubygems' :
name => 'rubygems',
}

package {
'libldap-ruby1.8' :
name => 'libldap-ruby1.8',
}

package { 'libldap2-dev' :
name => 'libldap2-dev',
}

package { 'libsasl2-dev' :
name => 'libsasl2-dev',
}

package { 'libsasl2-modules-ldap' :
name => 'libsasl2-modules-ldap',
}

# My Rubygem, with Provider type 'gem'
package {
'ruby-ldap' :
name => 'ruby-ldap',
provider => 'gem',
}

Package [ 'rubygems' ] -> Package [ 'ruby-ldap' ]
Package [ 'libldap2-dev' ] -> Package [ 'ruby-ldap' ]
Package [ 'libsasl2-modules-ldap' ] -> Package [ 'ruby-ldap' ]

When I test this manifest (with `puppet apply --noop test.pp`), I'm getting
the following output:

err: /Stage[main]//Package[ruby-ldap]: Provider gem is not functional
on this host

I also tried using classes and stages (doing the rubygem install in a stage
before the gem install) but I always got the `Provider gem`-error (but
maybe I just used the stages in a wrong way).

How can I install Rubygems packages on a system without Rubygems
preinstalled?


[1]:
https://groups.google.com/forum/?fromgroups#!topic/puppet-users/7DdudbY90cY