Bug #81458 [Com]: Regression in PHP 8.1: Incorrect difference after timezone change

Edit report at https://bugs.php.net/bug.php?id=81458&edit=1 ID: 81458 Comment by: antonino dot spampinato86 at gmail dot com Reported by: kylekatarnls at gmail dot com Summary: Regression in PHP 8.1: Incorrect difference after timezone change Status: Assigned Type: Bug Package: Date/time related PHP Version: 8.1Git-2021-09-18 (Git) Assigned To: derick Block user comment: N Private report: N New Comment: After explaining the difference between the new diff behavior from php 8.1 the algorithm has also changed unfortunately SetTimeZone uses the server time and not the DateTime diff object does not recognize +00: 00 but UTC for this reason forces UTC in the code. $first = (new DateTime('2018-07-01 00:00:00.000000 America/Toronto')); $first = (new DateTime('@' . $first->format('U'))); $first = (new DateTime($first->format('Y-m-d H:i:s'), new DateTimeZone('UTC'))); // ->setTimezone(new DateTimeZone('UTC')); $second = new DateTime('2018-07-02 00:00:00.000000 America/Toronto'); $result = $first->diff($second); var_dump($first); var_dump($second); var_dump('UTC ' . ((new DateTime('@' . $second->format('U')))->format('Y-m-d H:i:s'))); var_dump($result->days); var_dump($result->d); var_dump($result); Previous Comments: ------------------------------------------------------------------------ [2021-10-21 13:44:32] antonino dot spampinato86 at gmail dot com https://www.php.net/manual/en/datetime.examples-arithmetic.php diff from php 8.1 compares the dates for the moment, while previously subtracting or adding hours. The transition problem still exists, well the difference is one hour (backwards or forwards). Between these two dates what is the difference php is less accurate than the human calculation? 2010-03-01 America/Sydney to 2010-07-29 America/Sydney From php 8.1 4 months and 28 days. Never 5 months (old incorrect aritmetic). https://3v4l.org/5KhLZ Relative ti bug #52480 it is understandable to restore the old behavior but updating the documentation with the first note the calculation is wrong. ------------------------------------------------------------------------ [2021-10-21 13:23:19] cmb@php.net Related To: Bug #81263 ------------------------------------------------------------------------ [2021-10-21 10:53:24] cmb@php.net See <https://3v4l.org/RiYdl>. While there is obviously a behavioral change as of PHP 8.1.0, it seems to me that the new behavior of ::$days is correct. In the given test script there is a difference of 20 hours, and that is less than a day. Unfortunately, the documentation is not particularly clear whether this is to be expected, and why ::$d has a different result. Derick, can you please clarify? ------------------------------------------------------------------------ [2021-10-21 10:48:16] cmb@php.net The following pull request has been associated: Patch Name: Bug #81458: Add test On GitHub: https://github.com/php/php-src/pull/7601 Patch: https://github.com/php/php-src/pull/7601.patch ------------------------------------------------------------------------ [2021-10-11 07:57:26] alec at alec dot pl This is a bug and a regression. I hope it gets more attention before the final release. From a user perspective it is obvious that the compared DateTime objects needs to be "converted internally" to the same timezone to do the calculations. ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=81458 -- Edit this bug report at https://bugs.php.net/bug.php?id=81458&edit=1