lib/mongo/collection/view/readable.rb in mongo-2.0.2 vs lib/mongo/collection/view/readable.rb in mongo-2.0.3

@@ -230,10 +230,11 @@
         #
         # @return [ Hash, View ] Either the fields or a new +View+.
         #
         # @since 2.0.0
         def projection(document = nil)
+          validate_doc!(document) if document
           configure(:projection, document)
         end
 
         # The read preference to use for the query.
         #
@@ -354,9 +355,13 @@
           end
         end
 
         def to_return
           [ limit || batch_size, batch_size || limit ].min
+        end
+
+        def validate_doc!(doc)
+          raise Error::InvalidDocument.new unless doc.respond_to?(:keys)
         end
       end
     end
   end
 end