Question

If accessing an undefined index of a null reference, PHP does not throw any errors.

<?php

$array = &$foo['bar'];
if ($array['stuff']) echo 'Cool'; // No PHP notice
$array['thing'] = 1; // Array created; $foo['bar']['thing'] == 1
$array['stuff']; // PHP notice

If $array wasn’t a reference PHP would have complained on the first line.

Why doesn’t it for references? Do I need bother with isset for null references, or is PHP complaining internally and not letting me know?

Answer 1

In your code $array is null. The following code will not give you a notice either:

$b = null;
if ($b['stuff']) echo 'cool';

This is strange, this comment in the documentation points to that fact.