Suppress warnings from stream_select

[pavog]

Problem

In my setup, I use TaskMaster in a command that I execute from the CLI.
In my command, I use PCNTL to listen for signals such as SIGINT and then gracefully terminate the command. As soon as you press CTRL+C, the function is executed.
However, this also triggers the PHP warning from Taskmaster:
PHP Warning: stream_select(): Unable to select [4]: Interrupted system call (max_fd=10) in .../vendor/aternos/taskmaster/src/Taskmaster.php on line 291

Example code

SleepTask.php

<?php
namespace Aternos\Test;

class SleepTask extends \Aternos\Taskmaster\Task\Task {

    public function __construct(protected int $id)
    {
    }

    public function run(): void
    {
        echo "Task {$this->id} is sleeping...\n";
        sleep(3);
    }
}

test-command.php

<?php

require_once __DIR__ . '/vendor/autoload.php';

pcntl_async_signals(true);

function sig_handler($signo)
{
    switch ($signo) {
        case SIGINT:
            echo "Caught SIGINT, shutting down in 3 seconds...\n";
            sleep(3);
            echo "Exiting now...\n";
            exit;
        default:
            // handle all other signals
    }
}

pcntl_signal(SIGINT, "sig_handler");

$taskmaster = new \Aternos\Taskmaster\Taskmaster();
$taskmaster->autoDetectWorkers(4);

for ($i = 0; $i < 8; $i++) {
    $taskmaster->runTask(new \Aternos\Test\SleepTask($i));
}

$taskmaster->wait()->stop();

Output

> php test-command.php
Task 0 is sleeping...
Task 2 is sleeping...
Task 3 is sleeping...
Task 1 is sleeping...
^C
PHP Warning:  stream_select(): Unable to select [4]: Interrupted system call (max_fd=10) in .../vendor/aternos/taskmaster/src/Taskmaster.php on line 291
Caught SIGINT, shutting down in 3 seconds...
Exiting now...

Solution

To prevent this warning from being displayed, I add the @ sign to the stream_select call. This suppresses the warning.