Bug #63311 [Opn->Dup]: DateTime::add() adds wrong interval when switching from summer to winter time

Edit report at https://bugs.php.net/bug.php?id=63311&edit=1 ID: 63311 Updated by: heiglandreas@php.net Reported by: thomas dot mayer at 2bis10 dot de Summary: DateTime::add() adds wrong interval when switching from summer to winter time -Status: Open +Status: Duplicate Type: Bug Package: Date/time related Operating System: Windows 7, debian 6 PHP Version: 7.1 Block user comment: N Private report: N New Comment: We're now tracking this in https://bugs.php.net/bug.php?id=74274 Previous Comments: ------------------------------------------------------------------------ [2016-02-18 08:44:32] jan dot machala at email dot cz Problem still persists in newest php versions. There is online php shell test, which detects which php versions are affected (https://3v4l.org/femQK). ------------------------------------------------------------------------ [2014-11-11 08:21:26] YAfrourner5561 at superrito dot com Bug still persists ------------------------------------------------------------------------ [2014-03-31 11:37:28] nj dot johansson at gmail dot com Seems like there are many similar reported bugs that might be related to the same underlying issue: https://bugs.php.net/bug.php?id=51051 https://bugs.php.net/bug.php?id=60960 https://bugs.php.net/bug.php?id=61530 https://bugs.php.net/bug.php?id=62331 https://bugs.php.net/bug.php?id=62327 ------------------------------------------------------------------------ [2014-03-31 11:27:18] nj dot johansson at gmail dot com Experiencing the same thing on PHP 5.4.26 (RHEL 5.6) when subtracting an hour at the time across DST boundary. Test script: --------------- // Init DateTime after DST change $dt = new DateTime('2014-03-30 05:03:00', new DateTimeZone('Europe/Berlin')); $di = new DateInterval('PT1H'); // Subtract one hour each time and notice how time is stuck echo $dt->format('Y-m-d H:i:s') . "\n"; $dt->sub($di); echo $dt->format('Y-m-d H:i:s') . "\n"; $dt->sub($di); echo $dt->format('Y-m-d H:i:s') . "\n"; $dt->sub($di); echo $dt->format('Y-m-d H:i:s') . "\n"; $dt->sub($di); echo $dt->format('Y-m-d H:i:s') . "\n"; Result: ----------------- 2014-03-30 05:03:00 2014-03-30 04:03:00 2014-03-30 03:03:00 2014-03-30 03:03:00 2014-03-30 03:03:00 2014-03-30 03:03:00 ------------------------------------------------------------------------ [2013-07-03 15:01:06] mas at crosscan dot com For me it seems not to be directly connected with switching from or to DST. I tried the following Test script: ---------------- date_default_timezone_set( 'Europe/Berlin' ); $date = new \DateTime( '@0' ); echo $date->format('c')."\n"; $interval = new \DateInterval( 'PT1H' ); $date->add($interval); echo $date->format('c')."\n"; $date->add($interval); echo $date->format('c')."\n"; Expected result: ------------------ 1970-01-01T00:00:00+00:00 1970-01-01T01:00:00+00:00 1970-01-01T02:00:00+00:00 Actual result: ---------------- 1970-01-01T00:00:00+00:00 1970-01-01T02:00:00+00:00 1970-01-01T04:00:00+00:00 ------------------------------------------------------------------------ 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=63311 -- Edit this bug report at https://bugs.php.net/bug.php?id=63311&edit=1