Fwrite to stdout in childprocess not shown

Description

it won't write text there so you don't know there is a prompt. (fwrite(STDOUT, $text) also i get a timeout (execute timeout) in my own framework which holds some more code. and if i write something to stdin it wont get accepted / continue executing script.

test1.php

<?php 
$command = escapeshellcmd(PHP_BINARY) . ' ' . escapeshellarg(__DIR__ . '/test2.php');
var_dump(exec($command, $output)); 
var_dump($output);

test2.php

<?php
function my_readline($text='') { 
fwrite(STDOUT, $text); 
return trim(fgets(STDIN)); 
} 
$a = my_readline('test: ');
echo $a;

the fwrite to STDOUT isn't executed if i run test1.php

PHP Version

8.2

Working in php 7.4

Operating System

Debian 11.6

Riprodurre il comportamento con gli script test1.php e test2.php dell’issue su PHP 8.2 in Debian 11.6, confrontando il prompt su stdout e la gestione di stdin del processo figlio con PHP 7.4. Tracciare quindi il comportamento di exec e dell’I/O del processo figlio per identificare perché fwrite(STDOUT, $text) non è visibile o perché l’input non continua; il lavoro è concluso quando il prompt viene mostrato e l’input viene accettato senza timeout.