[ERROR] Json_writer: a member name was expected, Assertion `got_name == named_item_expected()' failed

CREATE TABLE t (a INT);

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

ANALYZE FORMAT=JSON SELECT * FROM t t1 WHERE t1.a IN (SELECT t2.a FROM t t2 WHERE t1.a IN (SELECT t3.a FROM t t3));

# Cleanup

DROP TABLE t;

2021-12-08 20:52:48 4 [ERROR] Json_writer: a member name was expected.

mariadbd: /data/src/10.8/sql/my_json_writer.cc:49: void Json_writer::on_start_object(): Assertion `got_name == named_item_expected()' failed.

211208 20:52:48 [ERROR] mysqld got signal 6 ;

#7  0x00007f5a371e3f36 in __GI___assert_fail (assertion=0x564ddc8c6a28 "got_name == named_item_expected()", file=0x564ddc8c6a50 "/data/src/10.8/sql/my_json_writer.cc", line=49, function=0x564ddc8c6a78 "void Json_writer::on_start_object()") at assert.c:101

#8  0x0000564ddbd0f6bc in Json_writer::on_start_object (this=0x7f5a31a0c6f0) at /data/src/10.8/sql/my_json_writer.cc:49

#9  0x0000564ddbd0d7da in Json_writer::start_object (this=0x7f5a31a0c6f0) at /data/src/10.8/sql/my_json_writer.cc:59

#10 0x0000564ddb95b00e in Json_writer_object::Json_writer_object (this=0x7f5a31a0c510, writer=0x7f5a31a0c6f0, str=0x0) at /data/src/10.8/sql/my_json_writer.h:445

#11 0x0000564ddbcc3abc in Explain_table_access::print_explain_json (this=0x7f5a200606a0, query=0x7f5a20056288, writer=0x7f5a31a0c6f0, is_analyze=true) at /data/src/10.8/sql/sql_explain.cc:1694

#12 0x0000564ddbcc18a5 in Explain_basic_join::print_explain_json_interns (this=0x7f5a2005fc90, query=0x7f5a20056288, writer=0x7f5a31a0c6f0, is_analyze=true) at /data/src/10.8/sql/sql_explain.cc:1105

#13 0x0000564ddbcc1262 in Explain_select::print_explain_json (this=0x7f5a2005fc90, query=0x7f5a20056288, writer=0x7f5a31a0c6f0, is_analyze=true) at /data/src/10.8/sql/sql_explain.cc:1001

#14 0x0000564ddbcbe412 in Explain_query::print_explain_json (this=0x7f5a20056288, output=0x7f5a20060a18, is_analyze=true) at /data/src/10.8/sql/sql_explain.cc:234

#15 0x0000564ddbcbe141 in Explain_query::send_explain (this=0x7f5a20056288, thd=0x7f5a20000db8) at /data/src/10.8/sql/sql_explain.cc:177

#16 0x0000564ddbaaff9c in execute_sqlcom_select (thd=0x7f5a20000db8, all_tables=0x7f5a20015b38) at /data/src/10.8/sql/sql_parse.cc:6265

#17 0x0000564ddbaa7168 in mysql_execute_command (thd=0x7f5a20000db8, is_called_from_prepared_stmt=false) at /data/src/10.8/sql/sql_parse.cc:3944

#18 0x0000564ddbab4d2a in mysql_parse (thd=0x7f5a20000db8, rawbuf=0x7f5a20015400 "ANALYZE FORMAT=JSON SELECT * FROM t t1 WHERE t1.a IN (SELECT t2.a FROM t t2 WHERE t1.a IN (SELECT t3.a FROM t t3))", length=114, parser_state=0x7f5a31a0d480) at /data/src/10.8/sql/sql_parse.cc:8028

#19 0x0000564ddbaa117e in dispatch_command (command=COM_QUERY, thd=0x7f5a20000db8, packet=0x7f5a2000b989 "", packet_length=114, blocking=true) at /data/src/10.8/sql/sql_parse.cc:1894

#20 0x0000564ddba9fb1a in do_command (thd=0x7f5a20000db8, blocking=true) at /data/src/10.8/sql/sql_parse.cc:1402

#21 0x0000564ddbc75559 in do_handle_one_connection (connect=0x564ddefa0b18, put_in_cache=true) at /data/src/10.8/sql/sql_connect.cc:1418

#22 0x0000564ddbc751e9 in handle_one_connection (arg=0x564ddefa3178) at /data/src/10.8/sql/sql_connect.cc:1312

#23 0x0000564ddc1786a7 in pfs_spawn_thread (arg=0x564ddefa0668) at /data/src/10.8/storage/perfschema/pfs.cc:2201

#24 0x00007f5a376fc609 in start_thread (arg=<optimized out>) at pthread_create.c:477

#25 0x00007f5a372cf293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

commit 73df7a30094a0fac8f59de1c91a7bce6cd3ff643

Author: Sergei Krivonos

Date:   Sun Nov 14 09:48:20 2021 +0200

    MDEV-27036: resolve duplicated key issues of JSON tracing outputs: