gistfile1.php

<?php

// Nous vérifions que l'utilisateur est bien du bon type pour ne pas appeler getLastActivity() sur un objet autre objet User
if ($user instanceof User && $user->getLastActivity() < $delay) {
    $user->setActiveNow();
    $this->em->flush($user);
}

if ($user instanceof User && $user->getLastActivity() < $delay) {
    $user->setActiveNow();
    $this->em->flush($user);
}

// CLEAN CODE APPROACH

private function isUserLastActivityBeforeDelay(User $user, $delay) {
  return $user->getLastActivity() < $delay;
}

if( $this->isUserActivityBeforeDelay($user, $delay) ) {
    $user->setActiveNow();
    $this->em->flush($user);
}

We do not need to use instance of because of the strong typing within the function arguments (User $user). PHP will throw an error if we do not pass the right interface.