Get error data too long when use values for bit(1).

[wshwsh12]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do?

create table t(id int primary key auto_increment, a bit(1));
insert into t values(1,1);
insert into t values(1,1) on duplicate key update id = values(id),a = values(a);

2. What did you expect to see?

No error.

3. What did you see instead?

tidb> create table t(id int primary key auto_increment, a bit(1));
Query OK, 0 rows affected (0.01 sec)

tidb> insert into t values(1,1);
Query OK, 1 row affected (0.00 sec)

tidb> insert into t values(1,1) on duplicate key update id = values(id),a = values(a);
ERROR 1406 (22001): Data Too Long, field len 1

4. What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?
   master and release-3.0.10