nullable json column can not update to null value

[majian-poper]

php version and amphp/mysql version

PHP 8.3.14 (cli) (built: Nov 19 2024 15:14:23) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.3.14, Copyright (c) Zend Technologies
    with Zend OPcache v8.3.14, Copyright (c), by Zend Technologies
    with Xdebug v3.4.0, Copyright (c) 2002-2024, by Derick Rethans

"amphp/mysql": "^3.0",

This is my code

$mysqlConfig = new MysqlConfig(
    host: '127.0.0.1',
    port: '3306',
    user: 'root',
    password: 'pass',
    database: 'db'
);

$db = connect($mysqlConfig);

$db->execute("drop table if exists `test`");
$db->execute("create table `test` (`id` bigint unsigned not null auto_increment primary key, `something` json null)");

$db->execute('insert into `test` (`something`) values (?), (?)', [
    json_encode(['a' => 1]),
    null,
]);

dump('before update');
dump(\iterator_to_array($db->query('select * from `test`')));

$db->execute('update `test` set `something` = ? where `id` = ?', [null, 1]); // <--- update sql query

dump('after update');
dump(\iterator_to_array($db->query('select * from `test`')));

output

"before update" 
array:2 [
  0 => array:2 [
    "id" => "1"
    "something" => "{"a": 1}"
  ]
  1 => array:2 [
    "id" => "2"
    "something" => null
  ]
] 

"after update" 
array:2 [
  0 => array:2 [
    "id" => "1"
    "something" => "{"a": 1}" // not affected
  ]
  1 => array:2 [
    "id" => "2"
    "something" => null
  ]
] 

also if we insert null json between other values,

$db->execute('insert into `test` (`something`) values (?), (?), (?)', [
    json_encode(['a' => 1]),
    null,
    json_encode(['c' => 1]),
]);

a Amp\Sql\SqlQueryError will be throw

 MySQL error (3140): #22032 Invalid JSON text: "The document is empty." at position 0 in value for column 'test.something'.