Index corruption with unique key and nopad collation (without DESC or HASH keys)

--source include/have_innodb.inc

CREATE TABLE t (id INT, b TEXT, KEY(id), PRIMARY KEY (b(2),id)) ENGINE=InnoDB COLLATE utf8mb3_general_nopad_ci;

INSERT INTO t VALUES

 (1,''),(2,'x'),(3,'x'),(4,UNHEX('0010')),(5,'x'),(6,'x'),(7,'x'),(8,'x'),

 (9,UNHEX('00')),(10,'x'),(11,''),(12,UNHEX('73')),(13,'+'),(14,'N');

CHECK TABLE t EXTENDED;

SELECT id FROM t WHERE id IN (4,8);

# Cleanup

DROP TABLE t;

CHECK TABLE t EXTENDED;

Table	Op	Msg_type	Msg_text

test.t	check	Warning	InnoDB: Index 'id' contains 14 entries, should be 13.

test.t	check	error	Corrupt

mysqltest: At line 10: query 'SELECT id FROM t WHERE id IN (4,8)' failed: 1712: Index t is corrupted

2023-09-17 19:42:51 4 [ERROR] InnoDB: Flagged corruption of `id` in table `test`.`t` in CHECK TABLE; Wrong count

2023-09-17 19:42:51 4 [ERROR] Got error 128 when reading table './test/t'

CHECK TABLE t EXTENDED;

Table	Op	Msg_type	Msg_text

test.t	check	Warning	InnoDB: Clustered index record not found for index `id` of table `test`.`t`: COMPACT RECORD(info_bits=0, 2 fields): {[4]    (0x80000004),[2]  (0x0010)}

test.t	check	Warning	InnoDB: Clustered index record not found for index `id` of table `test`.`t`: COMPACT RECORD(info_bits=0, 2 fields): {[4]    (0x80000009),[1] (0x00)}

test.t	check	Warning	InnoDB: The B-tree of index id is corrupted.

test.t	check	Warning	InnoDB: Index 'id' contains 12 entries, should be 14.

test.t	check	error	Corrupt

mysqltest: At line 10: query 'SELECT id FROM t WHERE id IN (4,8)' failed: ER_INDEX_CORRUPT (1712): Index t is corrupted

Warnings from just before the error:

Warning 180 InnoDB: Index id for table `test`.`t` is marked as corrupted 

Error 1712 Index t is corrupted

2023-09-17 19:45:03 4 [ERROR] InnoDB: Clustered index record not found for index `id` of table `test`.`t`: COMPACT RECORD(info_bits=0, 2 fields): {[4]    (0x80000004),[2]  (0x0010)}

2023-09-17 19:45:03 4 [ERROR] InnoDB: Clustered index record not found for index `id` of table `test`.`t`: COMPACT RECORD(info_bits=0, 2 fields): {[4]    (0x80000009),[1] (0x00)}

2023-09-17 19:45:03 4 [ERROR] InnoDB: Flagged corruption of `id` in table `test`.`t` in CHECK TABLE-check index

2023-09-17 19:45:03 4 [ERROR] Got error 128 when reading table './test/t'

2023-09-17 19:46:17 4 [ERROR] InnoDB: Clustered record for sec rec not found index `id` of table `test`.`t`

InnoDB: sec index record PHYSICAL RECORD: n_fields 2; compact format; info bits 0

 0: len 4; hex 80000004; asc     ;;

 1: len 2; hex 0010; asc   ;;

InnoDB: clust index record PHYSICAL RECORD: n_fields 5; compact format; info bits 0

 0: len 0; hex ; asc ;;

 1: len 4; hex 80000001; asc     ;;

 2: len 6; hex 000000000014; asc       ;;

 3: len 7; hex 83000001350322; asc     5 ";;

 4: len 0; hex ; asc ;;

2023-09-17 19:46:17 4 [ERROR] InnoDB: We detected index corruption in an InnoDB type table. You have to dump + drop + reimport the table or, in a case of widespread corruption, dump all InnoDB tables and recreate the whole tablespace. If the mariadbd server crashes after the startup or when you dump the tables. Please refer to https://mariadb.com/kb/en/library/innodb-recovery-modes/ for information about forcing recovery.

2023-09-17 19:46:17 4 [ERROR] mariadbd: Index for table 't' is corrupt; try to repair it

2023-09-17 19:46:17 4 [ERROR] mariadbd: Index for table 't' is corrupt; try to repair it