use Symfony\Component\ErrorHandler\Debug;
use Symfony\Component\ErrorHandler\ErrorHandler;
use Symfony\Component\ErrorHandler\DebugClassLoader;

Debug::enable();

// or enable only one feature
//ErrorHandler::register();
//DebugClassLoader::enable();

$data = ErrorHandler::call(static function () use ($filename, $datetimeFormat) {
    // if any code executed inside this anonymous function fails, a PHP exception
    // will be thrown, even if the code uses the '@' PHP silence operator
    $data = json_decode(file_get_contents($filename), true);
    $data['read_at'] = date($datetimeFormat);
    file_put_contents($filename, json_encode($data));

    return $data;
});