DatePeriod not taking into account microseconds for end date #13773

Description

The following code:

$period = new DatePeriod(
    new DateTime('2000-01-01 12:00:00'),
    new DateInterval('P1D'),
    new DateTime('2000-01-02 12:00:00.000001'),
);

foreach ($period as $date) {
    echo $date->format('Y-m-d H:i:s') . '<br/>';
}

Resulted in this output:

2000-01-01 12:00:00

But I expected this output instead:

2000-01-01 12:00:00
2000-01-02 12:00:00

My understanding is that if you're going to yield a new date from the DatePeriod, as long as it's less than the end date, then it's allowed, otherwise you've reached the end. So whether the end date is 1 microsecond or 1 whole second greater than a would-be newly yielded date, it is still greater than it and ought be allowed.

The only information I could find about this was from this comment: https://php.vn.ua/manual/en/class.dateperiod.php#124147

PHP Version

PHP 8.2.15

Operating System

Fedora Linux 38 (Workstation Edition)