Modify params_lookup() to be able to search module::varname

[javierbertoli]

Hi Al,

This patch adds a few extra lookups as we discussed a while ago, to let current 2.x modules to lookup hiera variables as proposed by puppet standards, module::varname.

Also, as an extra, I've updated the specs to run OK with rspec 1.0.

Regards, Javier

[alvagante]

Up to now I've avoided to add the module::param lookup because it's basically useless: the default hiera lookup in Puppet3 is done in any case, so actually the module::param notation works also with current params_lookup, the only issue being that it can't be merged for a global lookup ( if you have both module::param and param the latter is used).
But since the current behaviour for module::param is what will happen when we'll remove params_lookup, I prefer to keep it as it.
The other fixes to the spec tests are perfect, so would you maend the changes to params_lookup (and the relevant tests? eventually converting them to test that verify the current behavior)

[javierbertoli]

Emmm... surely I'm missing something here, but suppose you have this module/manifests/init.pp

class bla (
  somevar = params_lookup( 'somevar')
....
) {}

that call to param_lookup() will fall into lib/puppet/parser/functions/params_lookup.rb:

function_hiera(["#{module_name}_#{var_name}", ''])`.

or into

function_hiera(["#{var_name}", '']) if arguments[1] == 'global'

And the searches with lookupvar() follows the same logic.

I fail to see where bla::somevar will be searched for, as all the search calls have '_' hardcoded.

I also remember (blurrily) trying module::var when we discussed this and it failed to return the values from hiera.

Am I all wrong?

[Poil]

params_lookup return '' (empty string) if it cannot find a value. but puppet will lookup for ::class::variable before running the params_lookup

I really don't understand why params_lookup return an empty string and not undef.