BUG: locks not working as expected

Description

The following code:

<?php
$arquivo_lock = fopen("test.txt","a");

if (flock($arquivo_lock,LOCK_EX|LOCK_NB)) { 
    echo "Yes";
} else {
    echo "No";
}

sleep(10);

fclose($arquivo_lock);
?>

Save the simple code above to the file test.php, for example. Now, in less than 10 seconds apart, open 2 (or more) tabs on your browser calling the file test.php and you will see every tab will show you Yes after some seconds. It should show Yes only on the first tab, all the other should return immediatly with No because I am using LOCK_NB flag.

This bug is pretty simple to reproduce and other people also confirmed it on Stackoverflow when I reported there.

PHP Version

8.x

Operating System

Confirmed at least on centos 9 stream and windows 11

Comienza ejecutando la reproducción de dos pestañas de test.php con PHP 8.x en los entornos indicados CentOS 9 Stream y Windows 11, centrándote en flock con LOCK_EX|LOCK_NB. Rastrea el punto de entrada de flock y el comportamiento del bloqueo específico de cada plataforma; se considera terminado cuando la primera solicitud informa Yes, mientras que las solicitudes solapadas devuelven No inmediatamente, con cobertura para los entornos confirmados.