lib/mongoid/relations/referenced/many_to_many.rb in mongoid-3.0.21 vs lib/mongoid/relations/referenced/many_to_many.rb in mongoid-3.0.22

@@ -298,10 +298,10 @@
           #
           # @return [ Criteria ] The criteria.
           #
           # @since 2.1.0
           def criteria(metadata, object, type = nil)
-            apply_ordering(metadata.klass.all_of(_id: { "$in" => object }), metadata)
+            apply_ordering(metadata.klass.all_of(_id: { "$in" => object || [] }), metadata)
           end
 
           # Get the criteria that is used to eager load a relation of this
           # type.
           #