TO_DATE: MSAN/Valgrind errors in Item_func_to_date::fix_length_and_dec upon PREPARE with parameters

PREPARE stmt FROM "SELECT TO_DATE('2026-01-01' DEFAULT '2000-01-01' ON CONVERSION ERROR, ?)";

==348426== Conditional jump or move depends on uninitialised value(s)

==348426==    at 0x13D079C: Item_func_to_date::fix_length_and_dec(THD*) (item_timefunc.cc:5024)

==348426==    by 0x12F8AD4: Item_func::fix_fields(THD*, Item**) (item_func.cc:412)

==348426==    by 0xC9CEC1: Item::fix_fields_if_needed(THD*, Item**) (item.h:1143)

==348426==    by 0xC9CEF6: Item::fix_fields_if_needed_for_scalar(THD*, Item**) (item.h:1152)

==348426==    by 0xD27CC0: setup_fields(THD*, Bounds_checked_array<Item*>, List<Item>&, enum_column_usage, List<Item>*, List<Item>*, bool, THD_WHERE) (sql_base.cc:8261)

==348426==    by 0xE56D2C: JOIN::prepare(TABLE_LIST*, Item*, unsigned int, st_order*, bool, st_order*, Item*, st_order*, st_select_lex*, st_select_lex_unit*) (sql_select.cc:1603)

==348426==    by 0xF5ACD0: st_select_lex_unit::prepare_join(THD*, st_select_lex*, select_result*, unsigned long long, bool) (sql_union.cc:1112)

==348426==    by 0xF5C853: st_select_lex_unit::prepare(TABLE_LIST*, select_result*, unsigned long long) (sql_union.cc:1616)

==348426==    by 0xE2C988: mysql_test_select(Prepared_statement*, TABLE_LIST*) (sql_prepare.cc:1493)

==348426==    by 0xE2E650: check_prepared_statement(Prepared_statement*) (sql_prepare.cc:2305)

==348426==    by 0xE33570: Prepared_statement::prepare(char const*, unsigned int) (sql_prepare.cc:4239)

==348426==    by 0xE2F802: mysql_sql_stmt_prepare(THD*) (sql_prepare.cc:2808)

==348426==    by 0xDEAF81: mysql_execute_command(THD*, bool) (sql_parse.cc:3962)

==348426==    by 0xDF8546: mysql_parse(THD*, char*, unsigned int, Parser_state*) (sql_parse.cc:7895)

==348426==    by 0xDE461E: dispatch_command(enum_server_command, THD*, char*, unsigned int, bool) (sql_parse.cc:1878)

==348426==    by 0xDE2F77: do_command(THD*, bool) (sql_parse.cc:1417)

==350128==WARNING: MemorySanitizer: use-of-uninitialized-value

    #0 0x55df4f777768 in Item_func_to_date::fix_length_and_dec(THD*) /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/item_timefunc.cc:5024:7

    #1 0x55df4f553edd in Item_func::fix_fields(THD*, Item**) /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/item_func.cc:412:7

    #2 0x55df4e870887 in Item::fix_fields_if_needed(THD*, Item**) /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/item.h:1143:30

    #3 0x55df4e870887 in Item::fix_fields_if_needed_for_scalar(THD*, Item**) /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/item.h:1152:12

    #4 0x55df4e870887 in setup_fields(THD*, Bounds_checked_array<Item*>, List<Item>&, enum_column_usage, List<Item>*, List<Item>*, bool, THD_WHERE) /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/sql_base.cc:8261:15

    #5 0x55df4eb04080 in JOIN::prepare(TABLE_LIST*, Item*, unsigned int, st_order*, bool, st_order*, Item*, st_order*, st_select_lex*, st_select_lex_unit*) /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/sql_select.cc:1603:7

    #6 0x55df4ed6e05a in st_select_lex_unit::prepare_join(THD*, st_select_lex*, select_result*, unsigned long long, bool) /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/sql_union.cc:1112:22

    #7 0x55df4ed5fad0 in st_select_lex_unit::prepare(TABLE_LIST*, select_result*, unsigned long long) /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/sql_union.cc:1616:11

    #8 0x55df4eaa9528 in mysql_test_select(Prepared_statement*, TABLE_LIST*) /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/sql_prepare.cc:1493:13

    #9 0x55df4eaa9528 in check_prepared_statement(Prepared_statement*) /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/sql_prepare.cc:2305:10

    #10 0x55df4eaa9528 in Prepared_statement::prepare(char const*, unsigned int) /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/sql_prepare.cc:4239:12

    #11 0x55df4eaacb5e in mysql_sql_stmt_prepare(THD*) /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/sql_prepare.cc:2808:19

    #12 0x55df4ea28afd in mysql_execute_command(THD*, bool) /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/sql_parse.cc:3962:5

    #13 0x55df4ea13319 in mysql_parse(THD*, char*, unsigned int, Parser_state*) /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/sql_parse.cc:7895:18

    #14 0x55df4ea0c5f4 in dispatch_command(enum_server_command, THD*, char*, unsigned int, bool) /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/sql_parse.cc:1878:7

    #15 0x55df4ea143d1 in do_command(THD*, bool) /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/sql_parse.cc:1417:17

    #16 0x55df4eeafc2c in do_handle_one_connection(CONNECT*, bool) /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/sql_connect.cc:1503:11

    #17 0x55df4eeaf706 in handle_one_connection /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/sql_connect.cc:1415:5

    #18 0x55df4fd01767 in pfs_spawn_thread /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/storage/perfschema/pfs.cc:2198:3

    #19 0x7fcfa11a91c3 in start_thread nptl/pthread_create.c:442:8

    #20 0x7fcfa122985b in clone3 misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:81

  Memory was marked as uninitialized

    #0 0x55df4e5e03dd in __msan_allocated_memory (/share8t/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/mariadbd+0x92e3dd) (BuildId: 0fb7769527b189cbaabbfef5f2e839485a6f51b5)

    #1 0x55df50912584 in my_malloc /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/mysys/my_malloc.c:117:7

SUMMARY: MemorySanitizer: use-of-uninitialized-value /data/bld/preview-12.3/bb-12.3-MDEV-19683-to_date-msan/sql/item_timefunc.cc:5024:7 in Item_func_to_date::fix_length_and_dec(THD*)