Special character leads to assertion in my_wc_to_printable_generic on 10.5.2 (debug)

SET NAMES sjis;

SET @@CHARACTER_SET_CLIENT='cp1257';

(a(b 'т'));

mysqld: /data/git/10.5_dbg/strings/ctype.c:1072: my_wc_to_printable_generic: Assertion `0' failed.

Core was generated by `/data/MD180320-mariadb-10.5.2-linux-x86_64-dbg/bin/mysqld --no-defaults --core-'.

Program terminated with signal SIGABRT, Aborted.

#0  __pthread_kill (threadid=<optimized out>, signo=signo@entry=6)

    at ../sysdeps/unix/sysv/linux/pthread_kill.c:57

57	../sysdeps/unix/sysv/linux/pthread_kill.c: No such file or directory.

[Current thread is 1 (Thread 0x7f95613b7700 (LWP 11593))]

(gdb) bt

#0  __pthread_kill (threadid=<optimized out>, signo=signo@entry=6)

    at ../sysdeps/unix/sysv/linux/pthread_kill.c:57

#1  0x00005612a90737d4 in my_write_core (sig=sig@entry=6) at /data/git/10.5_dbg/mysys/stacktrace.c:518

#2  0x00005612a881cb5f in handle_fatal_signal (sig=6) at /data/git/10.5_dbg/sql/signal_handler.cc:325

#3  <signal handler called>

#4  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51

#5  0x00007f955fafb801 in __GI_abort () at abort.c:79

#6  0x00007f955faeb39a in __assert_fail_base (

    fmt=0x7f955fc727d8 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n", 

    assertion=assertion@entry=0x5612a93a1fcd "0", 

    file=file@entry=0x5612a97d93d0 "/data/git/10.5_dbg/strings/ctype.c", line=line@entry=1072, 

    function=function@entry=0x5612a97da460 <__PRETTY_FUNCTION__.12805> "my_wc_to_printable_generic")

    at assert.c:92

#7  0x00007f955faeb412 in __GI___assert_fail (assertion=assertion@entry=0x5612a93a1fcd "0", 

    file=file@entry=0x5612a97d93d0 "/data/git/10.5_dbg/strings/ctype.c", line=line@entry=1072, 

    function=function@entry=0x5612a97da460 <__PRETTY_FUNCTION__.12805> "my_wc_to_printable_generic")

    at assert.c:101

#8  0x00005612a90babd1 in my_wc_to_printable_generic (cs=0x5612a9d5aa60 <my_charset_sjis_japanese_ci>, 

    wc=<optimized out>, str=0x7f95613b5cfe "\201_ ];a\225\177", end=0x7f95613b5e6f "")

    at /data/git/10.5_dbg/strings/ctype.c:1072

#9  0x00005612a90bac42 in my_convert_using_func (to=0x7f95613b5cfe "\201_ ];a\225\177", 

    to@entry=0x7f95613b5c70 "You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'a(b '\201_ ];a\225\177", 

    to_length=to_length@entry=511, to_cs=to_cs@entry=0x5612a9d5aa60 <my_charset_sjis_japanese_ci>, 

    wc_mb=0x5612a90baa77 <my_wc_to_printable_generic>, from=0x7f9534c1ac1b "‚'))' at line 1", 

    from@entry=0x7f9534c1ab8b "You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'a(b 'Ń‚'))' at line 1", 

    from_length=from_length@entry=161, from_cs=0x5612a9d9d040 <my_charset_utf8mb3_general_ci>, 

    mb_wc=0x5612a90b3131 <my_utf8mb3_uni>, errors=0x7f95613b5c4c)

    at /data/git/10.5_dbg/strings/ctype.c:1141

#10 0x00005612a852d095 in convert_error_message (

    to=to@entry=0x7f95613b5c70 "You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'a(b '\201_ ];a\225\177", to_length=511, 

    to_length@entry=512, to_cs=0x5612a9d5aa60 <my_charset_sjis_japanese_ci>, 

    from=from@entry=0x7f9534c1ab8b "You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'a(b 'Ń‚'))' at line 1", 

    from_length=161, from_cs=0x5612a9d9d040 <my_charset_utf8mb3_general_ci>, errors=0x7f95613b5c4c)

    at /data/git/10.5_dbg/sql/sql_error.cc:957

#11 0x00005612a84834f2 in net_send_error_packet (thd=0x7f9534c15088, sql_errno=sql_errno@entry=1064, 

    err=<optimized out>, 

    err@entry=0x7f9534c1ab8b "You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'a(b 'Ń‚'))' at line 1", 

    sqlstate=sqlstate@entry=0x7f9534c1ab70 "42000") at /data/git/10.5_dbg/sql/protocol.cc:452

#12 0x00005612a84837cb in Protocol::send_error (this=0x7f9534c15650, sql_errno=1064, 

    err_msg=0x7f9534c1ab8b "You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'a(b 'Ń‚'))' at line 1", 

    sql_state=0x7f9534c1ab70 "42000") at /data/git/10.5_dbg/sql/protocol.cc:672

#13 0x00005612a84839f6 in Protocol::end_statement (this=0x7f9534c15650)

    at /data/git/10.5_dbg/sql/protocol.cc:596

#14 0x00005612a8570aab in dispatch_command (command=command@entry=COM_QUERY, 

    thd=thd@entry=0x7f9534c15088, packet=<optimized out>, packet@entry=0x7f9534c67089 "(a(b 'т'))", 

    packet_length=<optimized out>, packet_length@entry=11, is_com_multi=is_com_multi@entry=false, 

    is_next_command=is_next_command@entry=false) at /data/git/10.5_dbg/sql/sql_parse.cc:2430

#15 0x00005612a856ceaf in do_command (thd=0x7f9534c15088) at /data/git/10.5_dbg/sql/sql_parse.cc:1358

#16 0x00005612a86c6a09 in do_handle_one_connection (connect=<optimized out>, 

    connect@entry=0x7f953da2b3a8, put_in_cache=put_in_cache@entry=true)

    at /data/git/10.5_dbg/sql/sql_connect.cc:1422

#17 0x00005612a86c6d38 in handle_one_connection (arg=arg@entry=0x7f953da2b3a8)

    at /data/git/10.5_dbg/sql/sql_connect.cc:1319

#18 0x00005612a8b23cfc in pfs_spawn_thread (arg=0x7f955f045888)

    at /data/git/10.5_dbg/storage/perfschema/pfs.cc:2201

#19 0x00007f95607de6db in start_thread (arg=0x7f95613b7700) at pthread_create.c:463

#20 0x00007f955fbdc88f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95