Unexpected syntax error upon select from a Spider table, empty WHERE clause

--source plugin/spider/spider/include/init_spider.inc

SET spider_same_server_link= on;

eval create server s foreign data wrapper mysql options (host "127.0.0.1", database "test", user "root", port $MASTER_MYPORT);

CREATE TABLE t (a INT, b INT);

INSERT INTO t VALUES (1,2),(3,4);

CREATE TABLE t_spider (a INT, b INT) ENGINE=SPIDER COMMENT = "wrapper 'mysql', srv 's', table 't'";

SELECT * FROM t_spider WHERE a = 1 XOR b = 2;

# Cleanup

DROP TABLE t_spider, t;

--source plugin/spider/spider/include/deinit_spider.inc

mysqltest: At line 10: query 'SELECT * FROM t_spider WHERE a = 1 XOR b = 2' failed: 1064: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ')' at line 1

select t0.`a` `a`,t0.`b` `b` from `test`.`t` t0 where ()