elasticsearch/elasticsearch — pull request #3682 by vhyza (2013-09-13 12:42:06+00:00)
Title: Fixed inability to set keep_words_path in KeepWordFilter

It seems `keep_words_path` can't be set, because `keep_words` (`arrayKeepWords`) is not `null` when not defined in config. So `ElasticSearchIllegalArgumentException` is thrown.