Assertion in Table_triggers_list::change_table_name fails when upgrading #mysql50# database names with broken .TRG files

let $MYSQLD_DATADIR= `select @@datadir`;

CREATE DATABASE `#mysql50#a@b`;

USE `#mysql50#a@b`;

CREATE TABLE `#mysql50#c@d` (a INT);

CREATE TABLE t1 (a INT);

--write_file $MYSQLD_DATADIR/a@b/c@d.TRG

TYPE=TRIGGERS

EOF

--write_file $MYSQLD_DATADIR/a@b/t1.TRG

EOF

--exec $MYSQL_CHECK --fix-db-names --fix-table-names '#mysql50#a@b'

[ERROR] Invalid (old?) table or database name 'c@d'

mariadbd: /src/mariadb/sql/sql_trigger.cc:2614: static bool Table_triggers_list::change_table_name(THD*, TRIGGER_RENAME_PARAM*, const LEX_CSTRING*, const LEX_CSTRING*, const LEX_CSTRING*, const LEX_CSTRING*, const LEX_CSTRING*): Assertion `!param->got_error' failed.

#0  __pthread_kill_implementation (threadid=<optimized out>, signo=6, no_tid=0) at ./nptl/pthread_kill.c:44

#1  __pthread_kill_internal (threadid=<optimized out>, signo=6) at ./nptl/pthread_kill.c:89

#2  __GI___pthread_kill (threadid=<optimized out>, signo=6) at ./nptl/pthread_kill.c:100

#3  0x00005f2fa29b1d79 in my_write_core (sig=6) at /src/mariadb/mysys/stacktrace.c:424

#4  0x00005f2f9f714ac2 in handle_fatal_signal (sig=6) at /src/mariadb/sql/signal_handler.cc:298

#5  <signal handler called>

#6  __pthread_kill_implementation (threadid=<optimized out>, signo=6, no_tid=0) at ./nptl/pthread_kill.c:44

#7  __pthread_kill_internal (threadid=<optimized out>, signo=6) at ./nptl/pthread_kill.c:89

#8  __GI___pthread_kill (threadid=<optimized out>, signo=signo@entry=6) at ./nptl/pthread_kill.c:100

#9  0x00007efb2a845e2e in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/raise.c:26

#10 0x00007efb2a828888 in __GI_abort () at ./stdlib/abort.c:77

#11 0x00007efb2a8287f0 in __assert_fail_base (fmt=<optimized out>, assertion=<optimized out>, file=<optimized out>, line=<optimized out>, function=<optimized out>) at ./assert/assert.c:118

#12 0x00005f2f9e3322f3 in Table_triggers_list::change_table_name (thd=0x7dbb29ad0218, param=0x7afb17d113d0, db=0x7afb17d110b0, old_alias=0x7afb17d11050, old_table=0x7afb17d11070, new_db=0x7afb17d11090, new_table=0x7afb17d11030) at /src/mariadb/sql/sql_trigger.cc:2614

#13 0x00005f2f9e3cff8d in rename_triggers (thd=0x7dbb29ad0218, ddl_log_entry=0x7afb17a276c0, swap_tables=false) at /src/mariadb/sql/ddl_log.cc:1272

#14 0x00005f2f9e3d33c5 in ddl_log_execute_action (thd=0x7dbb29ad0218, mem_root=0x7afb17a27660, ddl_log_entry=0x7afb17a276c0) at /src/mariadb/sql/ddl_log.cc:1501

#15 0x00005f2f9e3dee91 in ddl_log_execute_entry_no_lock (thd=0x7dbb29ad0218, first_entry=1) at /src/mariadb/sql/ddl_log.cc:2456

#16 0x00005f2f9e3e3e99 in ddl_log_revert (thd=0x7dbb29ad0218, state=0x7afb17903340) at /src/mariadb/sql/ddl_log.cc:2988

#17 0x00005f2f9dc63425 in mysql_rename_tables (thd=0x7dbb29ad0218, table_list=0x7dcb29d00438, silent=true, if_exists=false) at /src/mariadb/sql/sql_rename.cc:212

#18 0x00005f2f9d6e9aaf in mysql_upgrade_db (thd=0x7dbb29ad0218, old_db=...) at /src/mariadb/sql/sql_db.cc:2021

#19 0x00005f2f9da950c4 in mysql_execute_command (thd=0x7dbb29ad0218, is_called_from_prepared_stmt=false) at /src/mariadb/sql/sql_parse.cc:5075

#20 0x00005f2f9dacf30c in mysql_parse (thd=0x7dbb29ad0218, rawbuf=0x7c8b29a40670 "ALTER DATABASE `#mysql50#a@b` UPGRADE DATA DIRECTORY NAME", length=57, parser_state=0x7afb17dff170) at /src/mariadb/sql/sql_parse.cc:7895

#21 0x00005f2f9da4b686 in dispatch_command (command=COM_QUERY, thd=0x7dbb29ad0218, packet=0x7d8b29c9c219 "ALTER DATABASE `#mysql50#a@b` UPGRADE DATA DIRECTORY NAME", packet_length=57, blocking=true) at /src/mariadb/sql/sql_parse.cc:1878

#22 0x00005f2f9da3f6e4 in do_command (thd=0x7dbb29ad0218, blocking=true) at /src/mariadb/sql/sql_parse.cc:1417

#23 0x00005f2f9e73ba2b in do_handle_one_connection (connect=0x7b7b299e4638, put_in_cache=true) at /src/mariadb/sql/sql_connect.cc:1503

#24 0x00005f2f9e73aaba in handle_one_connection (arg=0x7b7b299e4638) at /src/mariadb/sql/sql_connect.cc:1415

#25 0x00005f2fa0f0f710 in pfs_spawn_thread (arg=0x7c6b299e7418) at /src/mariadb/storage/perfschema/pfs.cc:2198

#26 0x00007efb2c25f803 in asan_thread_start (arg=0x7afb18d01000) at ../../../../src/libsanitizer/asan/asan_interceptors.cpp:239

#27 0x00007efb2a8a3d64 in start_thread (arg=<optimized out>) at ./nptl/pthread_create.c:448

#28 0x00007efb2a9373bc in __GI___clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:78