Bug #81072 [Com]: Incorrect behavior of DateTime->modify across DST changes
| From: | antonino dot spampinato86 at gmail dot com | Date: | Fri, 30 Jul 2021 10:43:46 +0000 |
| Subject: | Bug #81072 [Com]: Incorrect behavior of DateTime->modify across DST changes | ||
| References: | 1 | Groups: | php.bugs |
| Request: | Send a blank email to php-bugs+get-235471@lists.php.net to get a copy of this message | ||
Edit report at https://bugs.php.net/bug.php?id=81072&edit=1
ID: 81072
Comment by: antonino dot spampinato86 at gmail dot com
Reported by: ph-bugs at allenjb dot me dot uk
Summary: Incorrect behavior of DateTime->modify across DST
changes
Status: Open
Type: Bug
Package: Date/time related
PHP Version: 8.0.6
Block user comment: N
Private report: N
New Comment:
This is the refined version proposed. DST transition bug for modify function exists. Bug 74224
mentions that from php 8.1 that diff function has been changed and supports time not conversion to
UTC and this makes time or date calculations consistent with local time. Actually diff function also
suffers from DST or ST problems, If you deem it necessary I will also show it to you.
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;
$string = 'Start ' . $dtWith->format('Y-m-d H:i:s Z') . PHP_EOL;
for ($i = 0; $i < 4; $i++) {
$string .= "Round {$i}: ";
$dtWith = incrementWithSwitch($dtWith, $invert);
$dtWithout_test1 = incrementWithoutSwitch($dtWithout, $invert);
$string .= 'With switch: ' . $dtWith->format('Y-m-d H:i:s Z');
$string .= ' :: Without switch: '. $dtWithout->format('Y-m-d H:i:s Z') .
PHP_EOL;
}
$string .= '---' . PHP_EOL;
$dtWith = \DateTimeImmutable::createFromFormat('!Y-m-d H:i:s', '2021-03-27
23:00:00', $tz);
$dtWithout = $dtWith;
$invert = false;
$string .= 'Start ' . $dtWith->format('Y-m-d H:i:s Z') . PHP_EOL;
for ($i = 0; $i < 4; $i++) {
$string .= "Round {$i}: ";
$dtWith = incrementWithSwitch($dtWith, $invert);
$dtWithout = incrementWithoutSwitch($dtWithout, $invert);
$string .= 'With switch: ' . $dtWith->format('Y-m-d H:i:s Z');
$string .= ' :: Without switch: ' . $dtWithout->format('Y-m-d H:i:s Z') .
PHP_EOL;
}
print($string);
Expected:
Start 2021-03-28 04:00:00 3600
Round 0: With switch: 2021-03-28 03:00:00 3600 :: Without switch: 2021-03-28 03:00:00 3600
Round 1: With switch: 2021-03-28 02:00:00 3600 :: Without switch: 2021-03-28 02:00:00 3600
Round 2: With switch: 2021-03-28 00:00:00 0 :: Without switch: 2021-03-28 00:00:00 3600
Round 3: With switch: 2021-03-27 23:00:00 0 :: Without switch: 2021-03-27 23:00:00 3600
---
Start 2021-03-27 23:00:00 0
Round 0: With switch: 2021-03-28 00:00:00 0 :: Without switch: 2021-03-28 00:00:00 0
Round 1: With switch: 2021-03-28 02:00:00 3600 :: Without switch: 2021-03-28 02:00:00 3600
Round 2: With switch: 2021-03-28 03:00:00 3600 :: Without switch: 2021-03-28 03:00:00 3600
Round 3: With switch: 2021-03-28 04:00:00 3600 :: Without switch: 2021-03-28 04:00:00 3600
Actual: Start 2021-03-28 04:00:00 3600
Round 0: With switch: 2021-03-28 03:00:00 3600 :: Without switch: 2021-03-28 04:00:00 3600
Round 1: With switch: 2021-03-28 02:00:00 3600 :: Without switch: 2021-03-28 04:00:00 3600
Round 2: With switch: 2021-03-28 00:00:00 0 :: Without switch: 2021-03-28 04:00:00 3600
Round 3: With switch: 2021-03-27 23:00:00 0 :: Without switch: 2021-03-28 04:00:00 3600
---
Start 2021-03-27 23:00:00 0
Round 0: With switch: 2021-03-28 00:00:00 0 :: Without switch: 2021-03-28 00:00:00 0
Round 1: With switch: 2021-03-28 02:00:00 3600 :: Without switch: 2021-03-28 02:00:00 3600
Round 2: With switch: 2021-03-28 03:00:00 3600 :: Without switch: 2021-03-28 03:00:00 3600
Round 3: With switch: 2021-03-28 04:00:00 3600 :: Without switch: 2021-03-28 04:00:00 3600
Previous Comments:
------------------------------------------------------------------------
[2021-06-13 12:04:19] myminibuisness at gmail dot com
Great bugs subscribe for detail: https://studyparagraphs.co/paragraph-writing/
------------------------------------------------------------------------
[2021-05-30 04:22:13] php-bugs at lists dot php dot net
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.
------------------------------------------------------------------------
[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