See

closing as explained

thank you @stof, my question is that the change was in the version 5.0.0, however, we didn't observe this behavior in Symfony 6.3, so I'm wondering if I've missed something or if I still don't fully understand it.
if the change was introduced in Symfony 6.4., wouldn't it be considered a BC breaking change? If so, wouldn't it have been more appropriate to include it in Symfony 7. instead of 6.4?"

thank you

CC: @derrabus @xabbuh

The behavior change happened with #31957 in 5.0.0.

Can you produce a reproducer app for your issue, where we can observe the change of behavior you've described?

@makraz Did you by chance also update the recipes so that you now have other bootstrapping code in the front controller than you had before?

Yes, I updated the recipes, and all looks good in this part. I will share a reproducer app for the issue with more context 👌🏻

Can you share how your index.php file looked before you updated and how it is now?

Before (Symfony 6.3.2)

<?php

use App\Kernel;
use Symfony\Component\ErrorHandler\Debug;
use Symfony\Component\HttpFoundation\Request;

require dirname(__DIR__).'/config/bootstrap.php';

if ($_SERVER['APP_DEBUG']) {
    umask(0000);

    Debug::enable();
}

if ($trustedProxies = $_SERVER['TRUSTED_PROXIES'] ?? false) {
    Request::setTrustedProxies(explode(',', $trustedProxies), Request::HEADER_X_FORWARDED_FOR | Request::HEADER_X_FORWARDED_PORT | Request::HEADER_X_FORWARDED_PROTO);
}

if ($trustedHosts = $_SERVER['TRUSTED_HOSTS'] ?? false) {
    Request::setTrustedHosts([$trustedHosts]);
}

$kernel = new Kernel($_SERVER['APP_ENV'], (bool) $_SERVER['APP_DEBUG']);
$request = Request::createFromGlobals();
$response = $kernel->handle($request);
$response->send();
$kernel->terminate($request, $response);

Now (Symfony 6.4.2)

<?php

use App\Kernel;

require_once dirname(__DIR__).'/vendor/autoload_runtime.php';

return function (array $context) {
    return new Kernel($context['APP_ENV'], (bool) $context['APP_DEBUG']);
};

That's why: recipes are opt-in piece of code that are on your side of responsibility: you don't have to adopt their updates, and adopting them means possibly changing some behavior (as in: reconfiguring some defaults of your app).
Closing therefor.

thank you all 🙏🏼
I'm guessing that the last time we updated Symfony to 5.X or 6.X, we didn't update the recipes 😅, but now I updated them too.

Before:

"symfony/framework-bundle": {
        "version": "4.4",

After:

    "symfony/framework-bundle": {
        "version": "6.4",