Assertion failure upon updating a MERGE table via view

CREATE TABLE t (f INT) ENGINE=MyISAM;

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

CREATE TABLE tm (f INT) ENGINE=MERGE UNION (t) INSERT_METHOD=FIRST;

CREATE VIEW v AS SELECT f FROM tm;

UPDATE v SET f = 3;

# Cleanup

DROP VIEW v;

DROP TABLE tm, t;

mariadbd: /data/src/11.1/storage/myisammrg/ha_myisammrg.cc:860: int ha_myisammrg::attach_children(): Assertion `!this->file->children_attached' failed.

230503 21:31:14 [ERROR] mysqld got signal 6 ;

#9  0x00007fddeaa53df2 in __GI___assert_fail (assertion=0x560beb6cf260 "!this->file->children_attached", file=0x560beb6cec20 "/data/src/11.1/storage/myisammrg/ha_myisammrg.cc", line=860, function=0x560beb6cf880 "int ha_myisammrg::attach_children()") at ./assert/assert.c:101

#10 0x0000560bea3b73ed in ha_myisammrg::attach_children (this=0x61b0000261b8) at /data/src/11.1/storage/myisammrg/ha_myisammrg.cc:860

#11 0x0000560bea3bc69a in ha_myisammrg::extra (this=0x61b0000261b8, operation=HA_EXTRA_ATTACH_CHILDREN) at /data/src/11.1/storage/myisammrg/ha_myisammrg.cc:1367

#12 0x0000560be843314d in open_tables (thd=0x62b00007e218, options=..., start=0x7fdde3345c60, counter=0x6290000e6ca0, flags=0, prelocking_strategy=0x6290000e6cc0) at /data/src/11.1/sql/sql_base.cc:4768

#13 0x0000560be8419830 in open_tables (thd=0x62b00007e218, tables=0x7fdde3345c60, counter=0x6290000e6ca0, flags=0, prelocking_strategy=0x6290000e6cc0) at /data/src/11.1/sql/sql_base.h:267

#14 0x0000560be8438650 in open_tables_for_query (thd=0x62b00007e218, tables=0x6290000e6338, table_count=0x6290000e6ca0, flags=0, prelocking_strategy=0x6290000e6cc0) at /data/src/11.1/sql/sql_base.cc:5740

#15 0x0000560be87b5e47 in Sql_cmd_dml::prepare (this=0x6290000e6c88, thd=0x62b00007e218) at /data/src/11.1/sql/sql_select.cc:32458

#16 0x0000560be87b61a4 in Sql_cmd_dml::execute (this=0x6290000e6c88, thd=0x62b00007e218) at /data/src/11.1/sql/sql_select.cc:32520

#17 0x0000560be85deead in mysql_execute_command (thd=0x62b00007e218, is_called_from_prepared_stmt=false) at /data/src/11.1/sql/sql_parse.cc:4393

#18 0x0000560be85f633a in mysql_parse (thd=0x62b00007e218, rawbuf=0x6290000e6238 "UPDATE v SET f = 3", length=18, parser_state=0x7fdde3346a20) at /data/src/11.1/sql/sql_parse.cc:7760

#19 0x0000560be85ceab1 in dispatch_command (command=COM_QUERY, thd=0x62b00007e218, packet=0x629000258219 "UPDATE v SET f = 3", packet_length=18, blocking=true) at /data/src/11.1/sql/sql_parse.cc:1892

#20 0x0000560be85cb7ef in do_command (thd=0x62b00007e218, blocking=true) at /data/src/11.1/sql/sql_parse.cc:1405

#21 0x0000560be8a836e2 in do_handle_one_connection (connect=0x608000002eb8, put_in_cache=true) at /data/src/11.1/sql/sql_connect.cc:1416

#22 0x0000560be8a830a3 in handle_one_connection (arg=0x608000002e38) at /data/src/11.1/sql/sql_connect.cc:1318

#23 0x0000560be967c870 in pfs_spawn_thread (arg=0x617000005b98) at /data/src/11.1/storage/perfschema/pfs.cc:2201

#24 0x00007fddeaaa7fd4 in start_thread (arg=<optimized out>) at ./nptl/pthread_create.c:442

#25 0x00007fddeab285bc in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81

commit ee495b2235275925bb24c8b67bcf61c3c4a0f266

Author: Igor Babaev

Date:   Tue Sep 13 16:14:10 2022 -0700

    Fix after the latest rebase of commits for MDEV-28883