ReflectionClass can't detect readonly properties for mysqli

Description

The following code:

<?php
$reflection = new ReflectionClass(mysqli::class);
$props = [];
foreach ($reflection->getProperties() as $property) {
    $props[] = $property->getName() . ' | readonly: ' . (int) $property->isReadOnly();
}
print_r($props);

Resulted in this output:

Array
(
    [0] => affected_rows | readonly: 0
    [1] => client_info | readonly: 0
    [2] => client_version | readonly: 0
    [3] => connect_errno | readonly: 0
    [4] => connect_error | readonly: 0
    [5] => errno | readonly: 0
    [6] => error | readonly: 0
    [7] => error_list | readonly: 0
    [8] => field_count | readonly: 0
    [9] => host_info | readonly: 0
    [10] => info | readonly: 0
    [11] => insert_id | readonly: 0
    [12] => server_info | readonly: 0
    [13] => server_version | readonly: 0
    [14] => sqlstate | readonly: 0
    [15] => protocol_version | readonly: 0
    [16] => thread_id | readonly: 0
    [17] => warning_count | readonly: 0
)

But I expected this output instead:

Array
(
    [0] => affected_rows | readonly: 1
    [1] => client_info | readonly: 1
    [2] => client_version | readonly: 1
    [3] => connect_errno | readonly: 1
    [4] => connect_error | readonly: 1
    [5] => errno | readonly: 1
    [6] => error | readonly: 1
    [7] => error_list | readonly: 1
    [8] => field_count | readonly: 1
    [9] => host_info | readonly: 1
    [10] => info | readonly: 1
    [11] => insert_id | readonly: 1
    [12] => server_info | readonly: 1
    [13] => server_version | readonly: 1
    [14] => sqlstate | readonly: 1
    [15] => protocol_version | readonly: 1
    [16] => thread_id | readonly: 1
    [17] => warning_count | readonly: 1
)

PHP Version

PHP 8.3.8

Operating System

No response

まず、レポートにある ReflectionClass と mysqli::class の例を PHP 8.3.8 で再現し、その後、mysqli のプロパティがどのようにリフレクションに公開されるかを追跡します。完了条件は、列挙されたプロパティが readonly: 1 と報告し、この動作のリグレッションカバレッジがあることです。