Virtual columns: No warning on data truncation

MariaDB [test]> SET sql_mode = '';

Query OK, 0 rows affected (0.00 sec)

MariaDB [test]> CREATE TABLE t1(a INT);

Query OK, 0 rows affected (0.05 sec)

MariaDB [test]> INSERT INTO t1 VALUES(2147483647);

Query OK, 1 row affected (0.00 sec)

MariaDB [test]> ALTER TABLE t1 ADD COLUMN b SMALLINT AS (a) VIRTUAL, ALGORITHM=COPY, LOCK=SHARED;

Query OK, 1 row affected, 1 warning (0.16 sec)     

Records: 1  Duplicates: 0  Warnings: 1

MariaDB [test]> SHOW WARNINGS;

+---------+------+--------------------------------------------+

| Level   | Code | Message                                    |

+---------+------+--------------------------------------------+

| Warning | 1264 | Out of range value for column 'b' at row 1 |

+---------+------+--------------------------------------------+

1 row in set (0.00 sec)

MariaDB [test]> ALTER TABLE t1 ADD COLUMN c SMALLINT AS (a) VIRTUAL;

Query OK, 0 rows affected (0.10 sec)

Records: 0  Duplicates: 0  Warnings: 0  <-- No warning

MariaDB [test]> SELECT * FROM t1;

+------------+-------+-------+

| a          | b     | c     |

+------------+-------+-------+

| 2147483647 | 32767 | 32767 |

+------------+-------+-------+

1 row in set (0.00 sec)