ASAN errors in err_conv / field_unpack upon multi-UPDATE causing ER_DUP_ENTRY

--source include/have_innodb.inc

CREATE TABLE t1 (

  pk INT,

  a CHAR(3),

  b TEXT,

  c TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,

  d INT,

  PRIMARY KEY (pk),

  UNIQUE (b(3), c)

) ENGINE=InnoDB;

INSERT INTO t1 VALUES

  (1, 'foo', 'qux', '2025-08-15', 11),

  (2, 'bar', 'qux', '2037-01-11', 12);

CREATE TABLE t2 (f CHAR(3)) ENGINE=InnoDB;

INSERT INTO t2 VALUES ('abc'),('def');

--error ER_DUP_ENTRY

UPDATE t1 LEFT JOIN t2 ON (t1.a = t2.f) SET t1.d = 1;

# Cleanup

DROP TABLE t1, t2;

==23215==ERROR: AddressSanitizer: heap-use-after-free on address 0x62900014a288 at pc 0x5631fbc40edc bp 0x7f28e11ab5c0 sp 0x7f28e11ab5b0

READ of size 1 at 0x62900014a288 thread T27

    #0 0x5631fbc40edb in my_convert /data/src/10.2/strings/ctype.c:1122

    #1 0x5631fa13aa03 in copy_and_convert(char*, unsigned int, charset_info_st const*, char const*, unsigned int, charset_info_st const*, unsigned int*) /data/src/10.2/sql/sql_string.h:44

    #2 0x5631fa2e34ac in err_conv(char*, unsigned int, char const*, unsigned int, charset_info_st const*) /data/src/10.2/sql/sql_error.cc:947

    #3 0x5631fa15ab95 in ErrConvString::ptr() const /data/src/10.2/sql/sql_error.h:577

    #4 0x5631fac13887 in field_unpack(String*, Field*, unsigned char const*, unsigned int, bool) /data/src/10.2/sql/key.cc:397

    #5 0x5631fac13f07 in key_unpack(String*, TABLE*, st_key*) /data/src/10.2/sql/key.cc:440

    #6 0x5631fa9abd95 in print_keydup_error(TABLE*, st_key*, char const*, unsigned long) /data/src/10.2/sql/handler.cc:3481

    #7 0x5631fa9abfe5 in print_keydup_error(TABLE*, st_key*, unsigned long) /data/src/10.2/sql/handler.cc:3501

    #8 0x5631fa9ac531 in handler::print_error(int, unsigned long) /data/src/10.2/sql/handler.cc:3578

    #9 0x5631fa5e9dd9 in multi_update::send_data(List<Item>&) /data/src/10.2/sql/sql_update.cc:2225

    #10 0x5631fa485d04 in end_send /data/src/10.2/sql/sql_select.cc:20046

    #11 0x5631fa47f3a5 in evaluate_null_complemented_join_record /data/src/10.2/sql/sql_select.cc:19217

    #12 0x5631fa47d8e4 in sub_select(JOIN*, st_join_table*, bool) /data/src/10.2/sql/sql_select.cc:18918

    #13 0x5631fa47e82a in evaluate_join_record /data/src/10.2/sql/sql_select.cc:19094

    #14 0x5631fa47d82d in sub_select(JOIN*, st_join_table*, bool) /data/src/10.2/sql/sql_select.cc:18913

    #15 0x5631fa47b285 in do_select /data/src/10.2/sql/sql_select.cc:18418

    #16 0x5631fa4150da in JOIN::exec_inner() /data/src/10.2/sql/sql_select.cc:3651

    #17 0x5631fa412bf1 in JOIN::exec() /data/src/10.2/sql/sql_select.cc:3446

    #18 0x5631fa416474 in mysql_select(THD*, TABLE_LIST*, unsigned int, List<Item>&, Item*, unsigned int, st_order*, st_order*, Item*, st_order*, unsigned long long, select_result*, st_select_lex_unit*, st_select_lex*) /data/src/10.2/sql/sql_select.cc:3849

    #19 0x5631fa5e3ea0 in mysql_multi_update(THD*, TABLE_LIST*, List<Item>*, List<Item>*, Item*, unsigned long long, enum_duplicates, bool, st_select_lex_unit*, st_select_lex*, multi_update**) /data/src/10.2/sql/sql_update.cc:1643

    #20 0x5631fa35a211 in mysql_execute_command(THD*) /data/src/10.2/sql/sql_parse.cc:4132

    #21 0x5631fa3731d1 in mysql_parse(THD*, char*, unsigned int, Parser_state*, bool, bool) /data/src/10.2/sql/sql_parse.cc:7793

    #22 0x5631fa34c3d6 in dispatch_command(enum_server_command, THD*, char*, unsigned int, bool, bool) /data/src/10.2/sql/sql_parse.cc:1827

    #23 0x5631fa3491a1 in do_command(THD*) /data/src/10.2/sql/sql_parse.cc:1381

    #24 0x5631fa6d2ed5 in do_handle_one_connection(CONNECT*) /data/src/10.2/sql/sql_connect.cc:1336

    #25 0x5631fa6d2798 in handle_one_connection /data/src/10.2/sql/sql_connect.cc:1241

    #26 0x5631fba785e1 in pfs_spawn_thread /data/src/10.2/storage/perfschema/pfs.cc:1869

    #27 0x7f28f7f1d608 in start_thread /build/glibc-eX1tMB/glibc-2.31/nptl/pthread_create.c:477

    #28 0x7f28f7af9292 in __clone (/lib/x86_64-linux-gnu/libc.so.6+0x122292)

==23390==ERROR: AddressSanitizer: heap-use-after-free on address 0x6290002b22a0 at pc 0x55d4b3adbf8e bp 0x7f68d616e470 sp 0x7f68d616e460

READ of size 1 at 0x6290002b22a0 thread T12

    #0 0x55d4b3adbf8d in my_mb_wc_latin1 /data/src/10.6/strings/ctype-latin1.c:375

    #1 0x55d4b3b45301 in my_convert_using_func /data/src/10.6/strings/ctype.c:1161

    #2 0x55d4b1bee723 in err_conv(char*, unsigned int, char const*, unsigned int, charset_info_st const*) /data/src/10.6/sql/sql_error.cc:915

    #3 0x55d4b1a18cd4 in ErrBuff::set_str(char const*, unsigned long, charset_info_st const*) const /data/src/10.6/sql/sql_error.h:850

    #4 0x55d4b1a190f6 in ErrConvString::lex_cstring() const /data/src/10.6/sql/sql_error.h:888

    #5 0x55d4b27dcacb in field_unpack(String*, Field*, unsigned char const*, unsigned int, bool) /data/src/10.6/sql/key.cc:396

    #6 0x55d4b27dd219 in key_unpack(String*, TABLE*, st_key*) /data/src/10.6/sql/key.cc:441

    #7 0x55d4b251b335 in print_keydup_error(TABLE*, st_key*, char const*, unsigned long) /data/src/10.6/sql/handler.cc:3973

    #8 0x55d4b251b5f0 in print_keydup_error(TABLE*, st_key*, unsigned long) /data/src/10.6/sql/handler.cc:3996

    #9 0x55d4b251bbc6 in handler::print_error(int, unsigned long) /data/src/10.6/sql/handler.cc:4072

    #10 0x55d4b1ffa77a in multi_update::send_data(List<Item>&) /data/src/10.6/sql/sql_update.cc:2680

    #11 0x55d4b1e65268 in select_result_sink::send_data_with_check(List<Item>&, st_select_lex_unit*, unsigned long long) /data/src/10.6/sql/sql_class.h:5582

    #12 0x55d4b1e1ed5d in end_send /data/src/10.6/sql/sql_select.cc:22213

    #13 0x55d4b1e179ec in evaluate_null_complemented_join_record /data/src/10.6/sql/sql_select.cc:21342

    #14 0x55d4b1e15ee7 in sub_select(JOIN*, st_join_table*, bool) /data/src/10.6/sql/sql_select.cc:21040

    #15 0x55d4b1e16e68 in evaluate_join_record /data/src/10.6/sql/sql_select.cc:21219

    #16 0x55d4b1e15e30 in sub_select(JOIN*, st_join_table*, bool) /data/src/10.6/sql/sql_select.cc:21035

    #17 0x55d4b1e139af in do_select /data/src/10.6/sql/sql_select.cc:20543

    #18 0x55d4b1da0714 in JOIN::exec_inner() /data/src/10.6/sql/sql_select.cc:4726

    #19 0x55d4b1d9dbf5 in JOIN::exec() /data/src/10.6/sql/sql_select.cc:4504

    #20 0x55d4b1da2150 in mysql_select(THD*, TABLE_LIST*, List<Item>&, Item*, unsigned int, st_order*, st_order*, Item*, st_order*, unsigned long long, select_result*, st_select_lex_unit*, st_select_lex*) /data/src/10.6/sql/sql_select.cc:4982

    #21 0x55d4b1ff2d10 in mysql_multi_update(THD*, TABLE_LIST*, List<Item>*, List<Item>*, Item*, unsigned long long, enum_duplicates, bool, st_select_lex_unit*, st_select_lex*, multi_update**) /data/src/10.6/sql/sql_update.cc:1960

    #22 0x55d4b1ccae74 in mysql_execute_command(THD*) /data/src/10.6/sql/sql_parse.cc:4480

    #23 0x55d4b1ce3f7a in mysql_parse(THD*, char*, unsigned int, Parser_state*) /data/src/10.6/sql/sql_parse.cc:8016

    #24 0x55d4b1cba100 in dispatch_command(enum_server_command, THD*, char*, unsigned int, bool) /data/src/10.6/sql/sql_parse.cc:1897

    #25 0x55d4b1cb6e2d in do_command(THD*, bool) /data/src/10.6/sql/sql_parse.cc:1406

    #26 0x55d4b2119077 in do_handle_one_connection(CONNECT*, bool) /data/src/10.6/sql/sql_connect.cc:1410

    #27 0x55d4b21189d4 in handle_one_connection /data/src/10.6/sql/sql_connect.cc:1312

    #28 0x55d4b2e2a09e in pfs_spawn_thread /data/src/10.6/storage/perfschema/pfs.cc:2201

    #29 0x7f68e594b608 in start_thread /build/glibc-eX1tMB/glibc-2.31/nptl/pthread_create.c:477

    #30 0x7f68e551f292 in __clone (/lib/x86_64-linux-gnu/libc.so.6+0x122292)