Merge pull request puppetlabs#147 from mhellmic/master

don't fail on undef variable in merge

Author: adrienthebo

lib/puppet/parser/functions/merge.rb

@@ -22,6 +22,7 @@ module Puppet::Parser::Functions
     accumulator = Hash.new
     # Merge into the accumulator hash
     args.each do |arg|
+      next if arg.is_a? String and arg.empty? # empty string is synonym for puppet's undef
       unless arg.is_a?(Hash)
         raise Puppet::ParseError, "merge: unexpected argument type #{arg.class}, only expects hash arguments"
       end

spec/unit/puppet/parser/functions/merge_spec.rb

@@ -26,6 +26,11 @@
   describe 'when calling merge on the scope instance' do
     it 'should require all parameters are hashes' do
       expect { new_hash = scope.function_merge([{}, '2'])}.to raise_error(Puppet::ParseError, /unexpected argument type String/)
+      expect { new_hash = scope.function_merge([{}, 2])}.to raise_error(Puppet::ParseError, /unexpected argument type Fixnum/)
+    end
+
+    it 'should accept empty strings as puppet undef' do
+      expect { new_hash = scope.function_merge([{}, ''])}.not_to raise_error(Puppet::ParseError, /unexpected argument type String/)
     end
 
     it 'should be able to merge two hashes' do