PARTITION BY KEY and UNIQUE USING HASH treat equal CHAR values in a NO PAD collation as different: duplicate keys and missing rows

--source include/have_partition.inc

--source include/have_innodb.inc

SET NAMES utf8mb4;

# 'a', 'ä' and 'ａ' are equal in utf8mb4_unicode_nopad_ci

CREATE TABLE t1 (a CHAR(10) COLLATE utf8mb4_unicode_nopad_ci, PRIMARY KEY (a)) ENGINE=InnoDB PARTITION BY KEY (a) PARTITIONS 8;

INSERT IGNORE INTO t1 VALUES ('a'),('ä'),('ａ');

--let $c= query_get_value(SELECT COUNT(*) AS c FROM t1, c, 1)

if ($c != 1)

{

  --die The PRIMARY KEY holds $c values that are equal in utf8mb4_unicode_nopad_ci, where it must hold one

}

CREATE TABLE t2 (a CHAR(10) COLLATE utf8mb4_unicode_nopad_ci) PARTITION BY KEY (a) PARTITIONS 8;

INSERT INTO t2 VALUES ('a'),('ä'),('ａ');

--let $c= query_get_value(SELECT COUNT(*) AS c FROM t2 WHERE a='ä', c, 1)

if ($c != 3)

{

  --die The condition a='ä' finds $c of the 3 rows that are equal to 'ä' in utf8mb4_unicode_nopad_ci

}

CREATE TABLE t3 (a CHAR(10) COLLATE utf8mb4_unicode_nopad_ci, UNIQUE (a) USING HASH);

INSERT IGNORE INTO t3 VALUES ('a'),('ä'),('ａ');

--let $c= query_get_value(SELECT COUNT(*) AS c FROM t3, c, 1)

if ($c != 1)

{

  --die The UNIQUE USING HASH column holds $c values that are equal in utf8mb4_unicode_nopad_ci, where it must hold one

}

DROP TABLE t1, t2, t3;

mysqltest: At line 12: The PRIMARY KEY holds 3 values that are equal in utf8mb4_unicode_nopad_ci, where it must hold one