Unset(), when applied to array elements, leaves holes in the array.

Take this code:
$array = array("a");
unset($array[0]);
$array[] = "d";
var_dump($array);

This will produce the following output with PHP 3.0.12 and 3.0.13:
array(2) {
  int(1)
  string(1) "d"
}

a) It would make more sense if the index would be 0.
b) var_dump() sees the array as containing two elements. Count() works fine, though. PHP 4.x's var_dump() shows correctly array(1).