Cannot set exception code for custom exception

Description

The following code:

<?php

class Example extends \Exception {
  protected $code = 5;
}

echo '  → ', (new Example(''))->getCode(), \PHP_EOL;
echo '0 → ', (new Example('', 0))->getCode(), \PHP_EOL;
echo '1 → ', (new Example('', 1))->getCode(), \PHP_EOL;

Resulted in this output:

  → 5
0 → 5
1 → 1

But I expected this output instead:

  → 5
0 → 0
1 → 1

There is a note about default parameters in exception constructor on php.net. However, case 2 in the above example explicitly passes the code parameter to the constructor.

Calling the constructor of class Exception from a subclass ignores the default arguments, if the properties $code and $message are already set. about default parameters in exception constructor on php.net.

PHP Version

PHP 8.2

Operating System

Debian 11

该报告提供了一个涉及自定义 Exception 子类、Exception 构造函数和 getCode() 的 PHP 8.2 复现程序。首先在 php-src 中定位这些入口点，并复现全部三个构造函数调用。当显式传入的代码 0 得以保留，且其他演示的输出仍然正确时，即表示完成。