I have this code. Is it possible for a User object constructor to somehow fail so that $this->LoggedUser is assigned a NULL value and the object is freed after constructor returns?
$this->LoggedUser = NULL;
if ($_SESSION['verbiste_user'] != false)
$this->LoggedUser = new User($_SESSION['verbiste_user']);
Consider it this way. When you use new, you get a new object. Period. What you're doing is you have a function that searches for an existing user, and returns it when found. The best thing to express this is probably a static class function such as User::findUser(). This is also extensible to when you're deriving your classes from a base class.
A factory might be useful here:
class UserFactory
{
static public function create( $id )
{
return (
filter_var(
$id,
FILTER_VALIDATE_INT,
[ 'options' => [ 'min_range' => 1, ] ]
)
? new User( $id )
: null
);
}
}