Gotcha: Iterated lists of objects pass by reference in PHP!

foreach-object-list.php

<?php
// won't be incremented
$a  = [
    0,
    0,
];

// !! will be incremented !!
$b  = [
    (object)['count' => 0],
    (object)['count' => 0],
];

foreach ($a as $i) { $i++; }
foreach ($b as $o) { $o->count++; }

var_dump($a, $b);

output:

array(2) {
  [0]=>
  int(0)
  [1]=>
  int(0)
}


array(2) {
  [0]=>
  object(stdClass)#1 (1) {
    ["count"]=>
    int(1)
  }
  [1]=>
  object(stdClass)#2 (1) {
    ["count"]=>
    int(1)
  }
}