USE test;

CREATE TABLE t(a CHAR BINARY) ENGINE=InnoDB;

ALTER TABLE t CHANGE COLUMN a a CHAR(20);

mysqld: /test/10.5_dbg/storage/innobase/handler/handler0alter.cc:9106: bool innobase_rename_or_enlarge_column_try(ha_innobase_inplace_ctx*, trx_t*, const char*, ulint, const Field&, bool): Assertion `col->len == len' failed.

Core was generated by `/test/MD210420-mariadb-10.5.3-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

[Current thread is 1 (Thread 0x7faddd88c700 (LWP 955978))]

(gdb) bt

#0  __pthread_kill (threadid=<optimized out>, signo=signo@entry=6) at ../sysdeps/unix/sysv/linux/pthread_kill.c:57

#1  0x000055555bdaf03d in my_write_core (sig=sig@entry=6) at /test/10.5_dbg/mysys/stacktrace.c:518

#2  0x000055555b554d7b in handle_fatal_signal (sig=6) at /test/10.5_dbg/sql/signal_handler.cc:329

#3  <signal handler called>

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

#5  0x00007faddbfd0801 in __GI_abort () at abort.c:79

#6  0x00007faddbfc039a in __assert_fail_base (fmt=0x7faddc1477d8 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n", assertion=assertion@entry=0x55555c1a4094 "col->len == len", file=file@entry=0x55555c1994e8 "/test/10.5_dbg/storage/innobase/handler/handler0alter.cc", line=line@entry=9106, function=function@entry=0x55555c19eb00 <innobase_rename_or_enlarge_column_try(ha_innobase_inplace_ctx*, trx_t*, char const*, unsigned long, Field const&, bool)::__PRETTY_FUNCTION__> "bool innobase_rename_or_enlarge_column_try(ha_innobase_inplace_ctx*, trx_t*, const char*, ulint, const Field&, bool)") at assert.c:92

#7  0x00007faddbfc0412 in __GI___assert_fail (assertion=assertion@entry=0x55555c1a4094 "col->len == len", file=file@entry=0x55555c1994e8 "/test/10.5_dbg/storage/innobase/handler/handler0alter.cc", line=line@entry=9106, function=function@entry=0x55555c19eb00 <innobase_rename_or_enlarge_column_try(ha_innobase_inplace_ctx*, trx_t*, char const*, unsigned long, Field const&, bool)::__PRETTY_FUNCTION__> "bool innobase_rename_or_enlarge_column_try(ha_innobase_inplace_ctx*, trx_t*, const char*, ulint, const Field&, bool)") at assert.c:101

#8  0x000055555b96066a in innobase_rename_or_enlarge_column_try (is_v=<optimized out>, f=..., pos=0, table_name=0x7fadb00dfc2d "t", trx=0x7fadc7c033b0, ctx=0x7fadb00755b8) at /test/10.5_dbg/storage/innobase/handler/handler0alter.cc:9106

#9  innobase_rename_or_enlarge_columns_try (table_name=0x7fadb00dfc2d "t", trx=0x7fadc7c033b0, table=0x7fadb00f0088, altered_table=0x7faddd887a70, ctx=0x7fadb00755b8, ha_alter_info=0x7faddd8879d0) at /test/10.5_dbg/storage/innobase/handler/handler0alter.cc:9181

#10 commit_try_norebuild (ha_alter_info=ha_alter_info@entry=0x7faddd8879d0, ctx=ctx@entry=0x7fadb00755b8, altered_table=altered_table@entry=0x7faddd887a70, old_table=0x7fadb00f0088, trx=0x7fadc7c033b0, table_name=0x7fadb00dfc2d "t") at /test/10.5_dbg/storage/innobase/handler/handler0alter.cc:10095

#11 0x000055555b94d0fe in ha_innobase::commit_inplace_alter_table (this=0x7fadb0036ca0, altered_table=0x7faddd887a70, ha_alter_info=0x7faddd8879d0, commit=true) at /test/10.5_dbg/storage/innobase/handler/handler0alter.cc:10827

#12 0x000055555b563449 in handler::ha_commit_inplace_alter_table (this=0x7fadb0036ca0, altered_table=altered_table@entry=0x7faddd887a70, ha_alter_info=ha_alter_info@entry=0x7faddd8879d0, commit=commit@entry=true) at /test/10.5_dbg/sql/handler.cc:4725

#13 0x000055555b37559b in mysql_inplace_alter_table (thd=thd@entry=0x7fadb0015088, table_list=0x7fadb00741a0, table=table@entry=0x7fadb00f0088, altered_table=altered_table@entry=0x7faddd887a70, ha_alter_info=ha_alter_info@entry=0x7faddd8879d0, inplace_supported=inplace_supported@entry=HA_ALTER_INPLACE_INSTANT, target_mdl_request=0x7faddd888830, alter_ctx=0x7faddd8896c0) at /test/10.5_dbg/sql/sql_table.cc:7923

#14 0x000055555b3819e0 in mysql_alter_table (thd=thd@entry=0x7fadb0015088, new_db=new_db@entry=0x7fadb0019940, new_name=new_name@entry=0x7fadb0019d48, create_info=create_info@entry=0x7faddd88a2b0, table_list=<optimized out>, table_list@entry=0x7fadb00741a0, alter_info=alter_info@entry=0x7faddd88a1e0, order_num=0, order=0x0, ignore=false, if_exists=false) at /test/10.5_dbg/sql/sql_table.cc:10444

#15 0x000055555b404f31 in Sql_cmd_alter_table::execute (this=<optimized out>, thd=0x7fadb0015088) at /test/10.5_dbg/sql/sql_alter.cc:520

#16 0x000055555b2b0422 in mysql_execute_command (thd=thd@entry=0x7fadb0015088) at /test/10.5_dbg/sql/sql_parse.cc:5912

#17 0x000055555b2b7f2b in mysql_parse (thd=thd@entry=0x7fadb0015088, rawbuf=<optimized out>, length=<optimized out>, parser_state=parser_state@entry=0x7faddd88b450, is_com_multi=is_com_multi@entry=false, is_next_command=is_next_command@entry=false) at /test/10.5_dbg/sql/sql_parse.cc:7957

#18 0x000055555b2a3c45 in dispatch_command (command=command@entry=COM_QUERY, thd=thd@entry=0x7fadb0015088, packet=packet@entry=0x7fadb0067089 "ALTER TABLE t CHANGE COLUMN a a CHAR(20)", packet_length=packet_length@entry=40, is_com_multi=is_com_multi@entry=false, is_next_command=is_next_command@entry=false) at /test/10.5_dbg/sql/sql_parse.cc:1839

#19 0x000055555b2a249b in do_command (thd=0x7fadb0015088) at /test/10.5_dbg/sql/sql_parse.cc:1358

#20 0x000055555b3fd415 in do_handle_one_connection (connect=<optimized out>, connect@entry=0x7fadbbbc53a8, put_in_cache=put_in_cache@entry=true) at /test/10.5_dbg/sql/sql_connect.cc:1422

#21 0x000055555b3fd744 in handle_one_connection (arg=arg@entry=0x7fadbbbc53a8) at /test/10.5_dbg/sql/sql_connect.cc:1319

#22 0x000055555b85dfb0 in pfs_spawn_thread (arg=0x7faddb445b08) at /test/10.5_dbg/storage/perfschema/pfs.cc:2201

#23 0x00007faddccb36db in start_thread (arg=0x7faddd88c700) at pthread_create.c:463

#24 0x00007faddc0b188f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95