Add server facts when looking up values

During normal catalog compilation, server facts are added by the `compiler`
terminus prior to calling `Puppet::Parser::Compiler.compile`[1]. However, the
lookup application directly calls `Compiler.compile`, bypassing the `compiler`
terminus[2]. Therefore, server facts weren't being added when running the lookup
command.

Ideally, catalog compilation and the lookup command would compile the catalog in
the same way, but changing that is risky. For that to work, we would need to
pass the already resolved node and facts to the `compiler` terminus and the
terminus would need to add server facts to the node. However, the terminus
doesn't add server facts if the node is passed in. It only does that if it
resolves the node using the indirector[3].

Rather than mess with the terminus and break compilation, just load server facts
in the same way that the `compiler` terminus does.

[1] https://github.com/puppetlabs/puppet/blob/8.7.0/lib/puppet/indirector/catalog/compiler.rb#L56
[2] https://github.com/puppetlabs/puppet/blob/8.7.0/lib/puppet/application/lookup.rb#L407
[3] https://github.com/puppetlabs/puppet/blob/8.7.0/lib/puppet/indirector/catalog/compiler.rb#L390

Author: joshcooper

lib/puppet/application/lookup.rb

@@ -3,6 +3,7 @@
 require_relative '../../puppet/application'
 require_relative '../../puppet/pops'
 require_relative '../../puppet/node'
+require_relative '../../puppet/node/server_facts'
 require_relative '../../puppet/parser/compiler'
 
 class Puppet::Application::Lookup < Puppet::Application
@@ -403,6 +404,7 @@ def generate_scope
       end
     end
     node.environment = Puppet[:environment] if Puppet.settings.set_by_cli?(:environment)
+    node.add_server_facts(Puppet::Node::ServerFacts.load)
     Puppet[:code] = 'undef' unless options[:compile]
     compiler = Puppet::Parser::Compiler.new(node)
     if options[:node]

spec/fixtures/unit/application/environments/production/data/common.yaml

@@ -20,5 +20,7 @@ ab: "%{hiera('a')} and %{hiera('b')}"
 
 g: "This is%{facts.cx} in facts hash"
 
+h: "server version is %{server_facts.serverversion}"
+
 lookup_options:
   a: first

spec/unit/application/lookup_spec.rb

@@ -546,6 +546,13 @@ def run_lookup(lookup)
         expect(run_lookup(lookup)).to eql("This is G from facts in facts hash")
       end
 
+      it 'looks up server facts' do
+        lookup.options[:node] = node
+        lookup.options[:render_as] = :s
+        allow(lookup.command_line).to receive(:args).and_return(['h'])
+        expect(run_lookup(lookup)).to eql("server version is #{Puppet.version}")
+      end
+
       describe 'when retrieving given facts' do
         before do
           lookup.options[:node] = node