fix error messages, fix returning falsey values

Author: Maksym Melnychok

lib/puppet/parser/functions/dig.rb

@@ -9,24 +9,24 @@ module Puppet::Parser::Functions
     EOS
              ) do |arguments|
     # Two arguments are required
-    raise(Puppet::ParseError, "difference(): Wrong number of arguments " +
+    raise(Puppet::ParseError, "dig(): Wrong number of arguments " +
                               "given (#{arguments.size} for at least 2)") if arguments.size < 2
 
     hash, path, default = *arguments
 
     unless hash.is_a? Hash
-      raise(Puppet::ParseError, "first argument must be hash, " <<
+      raise(Puppet::ParseError, "dig(): first argument must be hash, " <<
                                 "given #{hash.class.name}")
     end
 
     unless path.is_a? Array
-      raise(Puppet::ParseError, "first argument must be an array, " <<
+      raise(Puppet::ParseError, "dig(): second argument must be an array, " <<
                                 "given #{path.class.name}")
     end
 
     path.each { |key| hash = hash[key] rescue nil }
 
-    hash || default
+    hash.nil? ? default : hash
   end
 end
 

spec/functions/dig_spec.rb

@@ -9,4 +9,5 @@
   it { is_expected.to run.with_params({"a" => "b"}, ["a"]).and_return("b") }
   it { is_expected.to run.with_params({"a" => {"b" => "c"}}, ["a", "b"]).and_return("c") }
   it { is_expected.to run.with_params({}, ["a", "b"], "d").and_return("d") }
+  it { is_expected.to run.with_params({"a" => false}, ["a"]).and_return(false) }
 end