(PUP-7174) Add 'call' to the Puppet built in language functions

[seanmil]

Per PUP-7174

[hlindberg]

Tests are failing with this error:

the call method should be callable as call on a Puppet language function with no arguments
     Failure/Error: raise ArgumentError, "Function #{self.class.name}(): Unknown function: '#{function_name}'" unless func_3x
     Puppet::PreformattedError:
       Evaluation Error: Error while evaluating a Function Call, Function call(): Unknown function: 'call_me' at line 2:16 on node test

[hlindberg]

This does not seem to take - not sure why.

[seanmil]

That was the bug I was referring to on Slack that I thought I had found. I've tested the call function in a full environment and it works for namedspaced Puppet language functions. However, it does not work for a non-namespaced Puppet language function. And that seems like a bug in internal_call_function to me. Based on my reading of the code and the API notes it sounds like internal_call_function should work equally for all types of functions. The loader seems unable to find it, but how/why that occurs I don't know. I started digging into the pops code, but quickly got lost.

[puppetcla]

CLA signed by all contributors.

[seanmil]

@hlindberg, I spent a bit more time looking into this one spec test failing and saw what I considered to be some surprising behavior. This is all tested on 2016.4.2

If I take an empty environment (without the call function patch) and define this in manifests/site.pp:

function mainfunc() { 'main manifest function' }
include test

and then create modules/test/manifests/init.pp with:

class test() {
    notify { mainfunc(): }
}

Then I get Error 500 on SERVER: Server Error: Evaluation Error: Unknown function: 'mainfunc' error.

According to https://docs.puppet.com/puppet/4.7/lang_write_functions_in_puppet.html#aside-writing-functions-in-the-main-manifest I believe that it should work.

Also interestingly, if I do: puppet apply -e "function foo() { 'FOO' } ; class test { notify { foo(): } } ; include test" it works and I get:

Notice: FOO
Notice: /Stage[main]/Test/Notify[FOO]/message: defined 'message' as 'FOO'
Notice: Applied catalog in 0.05 seconds

It also works in the agent/master scenario if I call the function directly in site.pp, but not from the module.

I feel like I am hitting the same (or a very similar) issue in the spec test. Given how simple the call function is, and that I'm seeing some odd behavior here, I don't feel it is a problem in the function itself, but rather something else (maybe the loader?)

I think I've hit the limit of what I can diagnose. Any ideas?

[seanmil]

I'm not sure why the appveyor build failed - it looks to be an unrelated problem. However, I have refactored the spec tests a bit and they are all passing for all the original test cases.

[hlindberg]

@seanmil the appveyor tests are failing because of a bug in a recent version of AppVeyor (errors related to UNC paths) - there are 4 failing tests (which we ignore for now).

[hlindberg]

Thanks @seanmil for the contribution!