Unexpected Results with PHP8 date_diff for Different Timezones

[nnks1010]

Description

In PHP 8.1.25, running date_diff against different time zones returned unexpected results.

https://3v4l.org/RFQMt

The following code:

<?php
date_default_timezone_set('Asia/Tokyo');
$nowDate = (new DateTime('2024-04-01 00:49:22'))->setTimeZone(new DateTimeZone('Asia/Tokyo'));
$endDate = (new DateTime('2024-04-01 08:48:22'))->setTimeZone(new DateTimeZone('UTC'));
echo date_diff($nowDate, $endDate)->format('%Y-%M-%D %H:%I:%S');

Resulted in this output:

-1-11-31 07:59:00

But I expected this output instead:

00-00-00 07:59:00

PHP Version

PHP 8.1.25

Operating System

Ubuntu 22.04

[nielsdos]

Looks to be very related to GH-13341... I'll have a brief look.

[nielsdos]

Bisect points to 818b46a
EDIT: it's the strcmp check here that was added that breaks it (may not be root cause, I just mean that removing it "fixes" this): https://github.com/derickr/timelib/blob/23ee16db3926f3e4c2a3e035d055baf5f920717d/interval.c#L150 and also in sort_old_to_new.
EDIT 2: I feel like this issue is in the normalization code

[derickr]

I have a patch for this, but I don't like it: https://github.com/derickr/timelib/pull/152/files#diff-237cc5b592e6e7b478088cbf255d391340d0a00113cb95ed096a34e9c7ca0ed1