Edit report at https://bugs.php.net/bug.php?id=81072&edit=1
ID: 81072
Updated by: php-bugs@lists.php.net
Reported by: ph-bugs at allenjb dot me dot uk
Summary: Incorrect behavior of DateTime->modify across DST
changes
-Status: Feedback
+Status: No Feedback
Type: Bug
Package: Date/time related
PHP Version: 8.0.6
Private report: N
New Comment:
No feedback was provided. The bug is being suspended because
we assume that you are no longer experiencing the problem.
If this is not the case and you are able to provide the
information that was requested earlier, please do so and
change the status of the bug back to "Re-Opened". Thank you.
Previous Comments:
------------------------------------------------------------------------
[2021-05-23 09:45:58] php-bugs at allenjb dot me dot uk
I've tested this with current master (8.1-dev) and the issue still exists.
I noticed a bug in the reproduction script I previously posted and have fixed it. Updated script: https://3v4l.org/01oD9
<?php
function incrementWithSwitch($date, $invert)
{
$timezone = $date->getTimezone();
$date = $date->setTimezone(new DateTimeZone('UTC'));
$date = $date->modify(($invert ? '-' : '+') . '1 hour');
$date = $date->setTimezone($timezone);
$date = $date->setTime((int)$date->format('H'), 0);
return $date;
}
function incrementWithoutSwitch($date, $invert)
{
$date = $date->modify(($invert ? '-' : '+') . '1 hour');
return $date;
}
$tz = new \DateTimeZone("Europe/London");
$dtWith = \DateTimeImmutable::createFromFormat("!Y-m-d H:i:s", "2021-03-28
04:00:00", $tz);
$dtWithout = $dtWith;
$invert = true;
for ($i = 0; $i < 4; $i++) {
print "\nRound {$i}:";
$dtWith = incrementWithSwitch($dtWith, $invert);
$dtWithout = incrementWithoutSwitch($dtWithout, $invert);
print "With switch: ". $dtWith->format(\DateTime::RFC3339);
print " :: Without switch: ". $dtWithout->format(\DateTime::RFC3339);
}
print "\n---\n";
$dtWith = \DateTimeImmutable::createFromFormat("!Y-m-d H:i:s", "2021-03-28
00:00:00");
$dtWithout = $dtWith;
$invert = false;
for ($i = 0; $i < 4; $i++) {
print "\nRound {$i}:";
$dtWith = incrementWithSwitch($dtWith, $invert);
$dtWithout = incrementWithoutSwitch($dtWithout, $invert);
print "With switch: ". $dtWith->format(\DateTime::RFC3339);
print " :: Without switch: ". $dtWithout->format(\DateTime::RFC3339);
}
------------------------------------------------------------------------
[2021-05-22 20:17:54] requinix@php.net
Looks like 3v4l.org is behind a few versions - maybe was impacted by the GitHub move.
I can't reproduce locally. Can you test in current master (8.1)? If it works there then this
may be a duplicate of 74274.
------------------------------------------------------------------------
[2021-05-22 18:55:52] ph-bugs at allenjb dot me dot uk
Description:
------------
See https://3v4l.org/hGXcr
Working on a fix for https://github.com/dragonmantank/cron-expression/issues/111
As you can see, when working backwards with ->modify("-1 hour") DateTime fails to
properly handle the DST change and keeps pushing the time forward to 03:00:00
Working forwards with ->modify("+1 hour") does not exhibit the same behavior.
(The code examples also show a workaround, which involved switching timezones while performing the
->modify)
Test script:
---------------
<?php
function incrementWithSwitch($date, $invert)
{
$timezone = $date->getTimezone();
$date = $date->setTimezone(new DateTimeZone('UTC'));
$date = $date->modify(($invert ? '-' : '+') . '1 hour');
$date = $date->setTimezone($timezone);
$date = $date->setTime((int)$date->format('H'), 0);
return $date;
}
function incrementWithoutSwitch($date, $invert)
{
$date = $date->modify(($invert ? '-' : '+') . '1 hour');
return $date;
}
$tz = new \DateTimeZone("Europe/London");
$dtWith = \DateTimeImmutable::createFromFormat("!Y-m-d H:i:s", "2021-03-28
04:00:00");
$dtWithout = $dtWith;
$invert = true;
for ($i = 0; $i < 3; $i++) {
print "\nRound {$i}:";
$dtWith = incrementWithSwitch($dtWith, $invert);
$dtWithout = incrementWithoutSwitch($dtWithout, $invert);
print "With switch: ". $dtWith->format(\DateTime::RFC3339);
print " :: Without switch: ". $dtWithout->format(\DateTime::RFC3339);
}
print "\n---\n";
$dtWith = \DateTimeImmutable::createFromFormat("!Y-m-d H:i:s", "2021-03-28
00:00:00");
$dtWithout = $dtWith;
$invert = false;
for ($i = 0; $i < 3; $i++) {
print "\nRound {$i}:";
$dtWith = incrementWithSwitch($dtWith, $invert);
$dtWithout = incrementWithoutSwitch($dtWithout, $invert);
print "With switch: ". $dtWith->format(\DateTime::RFC3339);
print " :: Without switch: ". $dtWithout->format(\DateTime::RFC3339);
}
Expected result:
----------------
Round 0:With switch: 2021-03-28T03:00:00+02:00 :: Without switch: 2021-03-28T03:00:00+02:00
Round 1:With switch: 2021-03-28T01:00:00+01:00 :: Without switch: 2021-03-28T01:00:00+02:00
Round 2:With switch: 2021-03-28T00:00:00+01:00 :: Without switch: 2021-03-28T00:00:00+02:00
---
Round 0:With switch: 2021-03-28T01:00:00+01:00 :: Without switch: 2021-03-28T01:00:00+01:00
Round 1:With switch: 2021-03-28T03:00:00+02:00 :: Without switch: 2021-03-28T03:00:00+02:00
Round 2:With switch: 2021-03-28T04:00:00+02:00 :: Without switch: 2021-03-28T04:00:00+02:00
Actual result:
--------------
Round 0:With switch: 2021-03-28T03:00:00+02:00 :: Without switch: 2021-03-28T03:00:00+02:00
Round 1:With switch: 2021-03-28T01:00:00+01:00 :: Without switch: 2021-03-28T03:00:00+02:00
Round 2:With switch: 2021-03-28T00:00:00+01:00 :: Without switch: 2021-03-28T03:00:00+02:00
---
Round 0:With switch: 2021-03-28T01:00:00+01:00 :: Without switch: 2021-03-28T01:00:00+01:00
Round 1:With switch: 2021-03-28T03:00:00+02:00 :: Without switch: 2021-03-28T03:00:00+02:00
Round 2:With switch: 2021-03-28T04:00:00+02:00 :: Without switch: 2021-03-28T04:00:00+02:00
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=81072&edit=1