PHP why (null === $variable) and not ($variable === null) in comparison? [duplicate]

Answer 1

Not only does it help prevent accidental assignments, but also avoids confusion when we do intentionally want to make an assignment when evaluating a condition.

if (null !== $article = $repository->findOneById($request->query->get('id'))) {
    $title = $article->getTitle();

    //....
}