(MODULES-3543) Fix define_with_params to handle undef properly

As described in PUP-6422,

	ensure_resources('File[/tmp/a]', { owner => undef })

would not actually create the file. This fixes it, and adds tests to prove
it.

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/puppet/parser/functions/defined_with_params.rb b/lib/puppet/parser/functions/defined_with_params.rb
index d7df306..ffc7241 100644
--- a/lib/puppet/parser/functions/defined_with_params.rb
+++ b/lib/puppet/parser/functions/defined_with_params.rb
@@ -26,7 +26,7 @@ ENDOFDOC
   ret = false
   if resource = findresource(reference.to_s)
     matches = params.collect do |key, value|
-      resource[key] == value
+      resource[key] == (value.eql?(:undef) ? nil : value)  # eql? avoids bugs caused by monkeypatching in puppet
     end
     ret = params.empty? || !matches.include?(false)
   end