Testing iterator implementations that return non-scalars for keys. See: https://jira.mongodb.org/browse/PHP-570

BadIdeaIterator.php

<?php

class BadIdeaIterator implements Iterator
{
    protected $position;
    protected $keys;
    protected $values;

    public function __construct(array $keys, array $values)
    {
        $this->position = 0;
        $this->keys = array_values($keys);
        $this->values = array_values($values);

        if (count($this->keys) !== count($this->values)) {
            throw new InvalidArgumentException('Number of keys and values differ');
        }
    }

    public function current()
    {
        return $this->values[$this->position];
    }

    public function key()
    {
        return $this->keys[$this->position];
    }

    public function next()
    {
        ++$this->position;
    }

    public function rewind()
    {
        $this->position = 0;
    }

    public function valid()
    {
        return array_key_exists($this->position, $this->keys);
    }
}

$keys = [null, new MongoId(), ['x' => 1, 'y' => 2]];
$values = ['a', 'b', 'c'];

$a = new BadIdeaIterator($keys, $values);

var_dump(iterator_to_array($a, false));
var_dump(iterator_to_array($a, true));