PDOStatement::$queryString "readonly" is not properly implemented

Description

The following code:

<?php
$stmt = new PDOStatement();
var_dump($stmt);
for($i=0;$i<10;$i++)
        $stmt->queryString = (string) $i;
var_dump($stmt);

Resulted in this output:

object(PDOStatement)#1 (0) {
  ["queryString"]=>
  uninitialized(string)
}
object(PDOStatement)#1 (1) {
  ["queryString"]=>
  string(1) "9"
}

But I expected this output instead:

object(PDOStatement)#1 (0) {
  ["queryString"]=>
  uninitialized(string)
}
Fatal error: Uncaught Error: Property queryString is read only in x.php:5

The reason this happens is because the following code is wrong:
https://github.com/php/php-src/blob/209e0d6ad29b1f49982c58088aadd9d1ad86a162/ext/pdo/pdo_stmt.c#L2008-L2014
The second loop iteration just reuses the cache slot and won't go through the write handler, bypassing the fake readonly check.
Either this should be relaxed or be fixed (i.e. "real readonly").

PHP Version

8.3+

Operating System

No response

首先阅读链接行中的 ext/pdo/pdo_stmt.c，并运行 issue 中的复现。完成的标志是，对 PDOStatement::$queryString 的重复赋值不再绕过 readonly 检查并产生预期的 Error；已有一个开放的 pull request 处理此问题。