fail on malformed sort

src/main/java/org/elasticsearch/search/sort/SortParseElement.java

@@ -79,6 +79,8 @@ public class SortParseElement implements SearchParseElement {
                     addCompoundSortField(parser, context, sortFields);
                 } else if (token == XContentParser.Token.VALUE_STRING) {
                     addSortField(context, sortFields, parser.text(), false, false, null, null, null, null);
+                } else {
+                    throw new ElasticSearchIllegalArgumentException("malformed sort format, within the sort array, an object, or an actual string are allowed");
                 }
             }
         } else if (token == XContentParser.Token.VALUE_STRING) {