Server crashes in my_strcasecmp_utf8 upon adding partition to app-versioned table

--source include/have_partition.inc

CREATE TABLE t1 (f INT, s DATE, e DATE, PERIOD FOR app(s,e), CONSTRAINT CHECK (f > 0)) PARTITION BY RANGE (f) (PARTITION p1 VALUES LESS THAN (100));

ALTER TABLE t1 ADD PARTITION (PARTITION p2 VALUES LESS THAN (200));

# Cleanup

DROP TABLE t1;

#3  <signal handler called>

#4  0x00005601629e4070 in my_strcasecmp_utf8 (cs=0x560163701380 <my_charset_utf8_general_ci>, s=0x7f8acc1339e0 "CONSTRAINT_1", t=0x0) at /data/src/10.4/strings/ctype-utf8.c:5109

#5  0x0000560161e3b2df in lex_string_cmp (charset=0x560163701380 <my_charset_utf8_general_ci>, a=0x7f8acc139700, b=0x7f8acc014bb0) at /data/src/10.4/sql/lex_string.h:28

#6  0x0000560161e479de in mysql_prepare_create_table (thd=0x7f8acc000b00, create_info=0x7f8add7d0d10, alter_info=0x7f8add7d0c50, db_options=0x7f8add7ce62c, file=0x7f8acc1378c8, key_info_buffer=0x7f8add7ce5f8, key_count=0x7f8add7ce628, create_table_mode=-1) at /data/src/10.4/sql/sql_table.cc:4331

#7  0x0000560161e4046e in mysql_write_frm (lpt=0x7f8add7ce5c0, flags=1) at /data/src/10.4/sql/sql_table.cc:1825

#8  0x00005601622ae6ab in fast_alter_partition_table (thd=0x7f8acc000b00, table=0x7f8acc136a60, alter_info=0x7f8add7d0c50, create_info=0x7f8add7d0d10, table_list=0x7f8acc013250, db=0x7f8add7d0140, table_name=0x7f8add7d0150) at /data/src/10.4/sql/sql_partition.cc:7266

#9  0x0000560161e57817 in mysql_alter_table (thd=0x7f8acc000b00, new_db=0x7f8acc0052b8, new_name=0x7f8acc0056c0, create_info=0x7f8add7d0d10, table_list=0x7f8acc013250, alter_info=0x7f8add7d0c50, order_num=0, order=0x0, ignore=false) at /data/src/10.4/sql/sql_table.cc:9837

#10 0x0000560161ef0485 in Sql_cmd_alter_table::execute (this=0x7f8acc0140d0, thd=0x7f8acc000b00) at /data/src/10.4/sql/sql_alter.cc:508

#11 0x0000560161d6e1a3 in mysql_execute_command (thd=0x7f8acc000b00) at /data/src/10.4/sql/sql_parse.cc:6099

#12 0x0000560161d738ec in mysql_parse (thd=0x7f8acc000b00, rawbuf=0x7f8acc013118 "ALTER TABLE t1 ADD PARTITION (PARTITION p2 VALUES LESS THAN (200))", length=66, parser_state=0x7f8add7d2170, is_com_multi=false, is_next_command=false) at /data/src/10.4/sql/sql_parse.cc:7909

#13 0x0000560161d5e8ec in dispatch_command (command=COM_QUERY, thd=0x7f8acc000b00, packet=0x7f8acc008321 "ALTER TABLE t1 ADD PARTITION (PARTITION p2 VALUES LESS THAN (200))", packet_length=66, is_com_multi=false, is_next_command=false) at /data/src/10.4/sql/sql_parse.cc:1843

#14 0x0000560161d5cf36 in do_command (thd=0x7f8acc000b00) at /data/src/10.4/sql/sql_parse.cc:1360

#15 0x0000560161ee6c47 in do_handle_one_connection (connect=0x560164959b80) at /data/src/10.4/sql/sql_connect.cc:1412

#16 0x0000560161ee6996 in handle_one_connection (arg=0x560164959b80) at /data/src/10.4/sql/sql_connect.cc:1316

#17 0x000056016291cda3 in pfs_spawn_thread (arg=0x5601649bd510) at /data/src/10.4/storage/perfschema/pfs.cc:1862

#18 0x00007f8ae51754a4 in start_thread (arg=0x7f8add7d3700) at pthread_create.c:456

#19 0x00007f8ae36bdd0f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:97

commit db4a27ab738c3ab43173368117583402f995c4f1

Merge: d1ef02e9592 396da1a7054

Author: Marko Mäkelä

Date:   Sat Aug 31 06:53:45 2019 +0300

    Merge 10.3 into 10.4