UBSAN: strings/ctype-mb.c:261:32: runtime error: applying non-zero offset 2 to null pointer main.long_unique_bugs

# MDEV-39559: Assertion `b` failed in `my_strnncoll_xxxx_nopad_ci`

#

SET @old_trx_iso_level := @@session.transaction_isolation;

SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED;

CREATE TABLE t (x TEXT, UNIQUE(x))

ENGINE=InnoDB

CHARACTER SET utf8mb3 COLLATE utf8mb3_general_nopad_ci

SELECT '' AS x;

DROP TABLE t;

SET @@session.transaction_isolation = @old_trx_iso_level;

create table t1 (b text, key(b(10))) engine=myisam

character set utf8mb3 collate utf8mb3_general_nopad_ci

select '' as b union all select '0' as b union all select '1' as b;

select * from t1 force index(b) where b >= '' and b < '2';

b

0

1

drop table t1;

# End of 11.8 tests

line

/home/buildbot/src/strings/ctype-mb.c:261:32: runtime error: applying non-zero offset 2 to null pointer

SUMMARY: UndefinedBehaviorSanitizer: nullptr-with-nonzero-offset /home/buildbot/src/strings/ctype-mb.c:261:32 

^ Found warnings in /dev/shm/normal/10/log/mysqld.1.err