puppet-elasticsearch: Version 6.x.x does not work with Puppet 4

• Module version: every release from 6.0.0 to 6.3.0
• Puppet version: 4.8.1 on master, 4.10.12 on agent
• OS and version: Debian 8.10

Bug description

The puppet run fails with the following error:

Error while evaluating a Resource Statement, undefined method `pop' for nil:NilClass at /etc/puppetlabs/code/environments/<myenvironment>/nodes/mynode.pp:2:3 on node mynode

Stacktrace shown on the Puppet Master:

/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/lookup/invocation.rb:79:in `with'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/data_providers/lookup_adapter.rb:149:in `do_lookup'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/data_providers/lookup_adapter.rb:72:in `lookup'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/lookup.rb:77:in `search_and_merge'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/resource/type.rb:401:in `inject_external_parameters'
org/jruby/RubyKernel.java:1242:in `catch'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/resource/type.rb:400:in `inject_external_parameters'
org/jruby/RubyHash.java:1342:in `each'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/resource/type.rb:396:in `inject_external_parameters'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/resource/type.rb:363:in `set_resource_parameters'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/resource/type.rb:171:in `evaluate_code'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/resource.rb:81:in `evaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/profiler/around_profiler.rb:58:in `profile'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/profiler.rb:51:in `profile'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/resource.rb:73:in `evaluate'
org/jruby/RubyArray.java:1613:in `each'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/compiler.rb:395:in `evaluate_classes'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/runtime3_resource_support.rb:61:in `create_resources'
org/jruby/RubyArray.java:2414:in `map'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/runtime3_resource_support.rb:37:in `create_resources'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/runtime3_support.rb:321:in `create_resources'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/evaluator_impl.rb:842:in `eval_ResourceExpression'
org/jruby/RubyArray.java:2414:in `map'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/evaluator_impl.rb:839:in `eval_ResourceExpression'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/visitor.rb:69:in `visit_this_1'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/evaluator_impl.rb:82:in `evaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/evaluator_impl.rb:638:in `eval_BlockExpression'
org/jruby/RubyArray.java:1613:in `each'
org/jruby/RubyEnumerable.java:852:in `inject'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/evaluator_impl.rb:638:in `eval_BlockExpression'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/visitor.rb:69:in `visit_this_1'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/evaluator_impl.rb:82:in `evaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/parser/evaluating_parser.rb:63:in `evaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/ast/pops_bridge.rb:32:in `evaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/ast/pops_bridge.rb:72:in `evaluate'
org/jruby/RubyKernel.java:1242:in `catch'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/ast/pops_bridge.rb:71:in `evaluate'
org/jruby/RubyKernel.java:1242:in `catch'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/ast/pops_bridge.rb:70:in `evaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/ast.rb:31:in `safeevaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/resource/type.rb:184:in `evaluate_code'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/resource.rb:81:in `evaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/profiler/around_profiler.rb:58:in `profile'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/profiler.rb:51:in `profile'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/resource.rb:73:in `evaluate'
org/jruby/RubyArray.java:1613:in `each'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/compiler.rb:395:in `evaluate_classes'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/runtime3_resource_support.rb:61:in `create_resources'
org/jruby/RubyArray.java:2414:in `map'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/runtime3_resource_support.rb:37:in `create_resources'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/runtime3_support.rb:321:in `create_resources'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/evaluator_impl.rb:842:in `eval_ResourceExpression'
org/jruby/RubyArray.java:2414:in `map'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/evaluator_impl.rb:839:in `eval_ResourceExpression'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/visitor.rb:69:in `visit_this_1'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/evaluator_impl.rb:82:in `evaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/evaluator_impl.rb:638:in `eval_BlockExpression'
org/jruby/RubyArray.java:1613:in `each'
org/jruby/RubyEnumerable.java:852:in `inject'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/evaluator_impl.rb:638:in `eval_BlockExpression'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/visitor.rb:69:in `visit_this_1'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/evaluator/evaluator_impl.rb:82:in `evaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/pops/parser/evaluating_parser.rb:63:in `evaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/ast/pops_bridge.rb:32:in `evaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/ast.rb:31:in `safeevaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/resource/type.rb:181:in `evaluate_code'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/scope.rb:944:in `with_guarded_scope'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/resource/type.rb:179:in `evaluate_code'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/resource.rb:81:in `evaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/profiler/around_profiler.rb:58:in `profile'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/profiler.rb:51:in `profile'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/resource.rb:73:in `evaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/compiler.rb:555:in `evaluate_ast_node'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/compiler.rb:178:in `compile'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/profiler/around_profiler.rb:58:in `profile'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/profiler.rb:51:in `profile'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/compiler.rb:178:in `compile'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/context.rb:65:in `override'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet.rb:241:in `override'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/compiler.rb:162:in `compile'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/parser/compiler.rb:33:in `compile'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/indirector/catalog/compiler.rb:266:in `compile'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/profiler/around_profiler.rb:58:in `profile'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/profiler.rb:51:in `profile'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/indirector/catalog/compiler.rb:264:in `compile'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util.rb:223:in `benchmark'
/opt/puppetlabs/server/apps/puppetserver/puppet-server-release.jar!/META-INF/jruby.home/lib/ruby/1.9/benchmark.rb:295:in `realtime'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util.rb:222:in `benchmark'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/indirector/catalog/compiler.rb:262:in `compile'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/indirector/catalog/compiler.rb:53:in `find'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/indirector/indirection.rb:194:in `find'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/network/http/api/indirected_routes.rb:121:in `do_find'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/network/http/api/indirected_routes.rb:48:in `call'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/context.rb:65:in `override'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet.rb:241:in `override'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/network/http/api/indirected_routes.rb:47:in `call'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/network/http/route.rb:82:in `process'
org/jruby/RubyArray.java:1613:in `each'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/network/http/route.rb:81:in `process'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/network/http/route.rb:87:in `process'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/network/http/route.rb:87:in `process'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/network/http/handler.rb:60:in `process'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/profiler/around_profiler.rb:58:in `profile'

Example node definition:

class { "elasticsearch":
  version => "6.3.0"
}

The module works fine on Puppet 5 but not on Puppet 4, but the documentation says it requires Puppet >= 4.5.0 < 6.0.0.