Bug #80913 [Ver]: DateTime(Immutable)::sub around DST yield incorrect time
Edit report at https://bugs.php.net/bug.php?id=80913&edit=1
ID: 80913
Updated by: cmb@php.net
Reported by: acm at tweakers dot net
Summary: DateTime(Immutable)::sub around DST yield incorrect
time
Status: Verified
Type: Bug
Package: Date/time related
Operating System: all
PHP Version: 8.0.3
Block user comment: N
Private report: N
New Comment:
This affects older PHP versions as well[1]. Interestingly, there
is some code which is supposed to cater to that[2], but it is not
executed since t->dst==1.
[1] <https://3v4l.org/KKHlK>
[2] <https://github.com/php/php-src/blob/php-7.4.16/ext/date/lib/interval.c#L126>
Previous Comments:
------------------------------------------------------------------------
[2021-03-29 16:00:21] cmb@php.net
This affects older PHP versions as well[1]. Interestingly, there
is some code which is supposed to cater to that[2], but it is not
executed since t->dst==1.
[1] <https://3v4l.org/KKHlK>
[2] <https://github.com/php/php-src/blob/php-7.4.16/ext/date/lib/interval.c#L126>
------------------------------------------------------------------------
[2021-03-29 07:43:44] acm at tweakers dot net
Description:
------------
DateTimeImmutable and DateTime with a time like '2021-03-28 03:00:00' in
'Europe/Amsterdam' (i.e. the moment of the DST-transition) will give the wrong time when
substracting less than an hour.
The same goes for all times that will give a result within an hour from 03:00+02:00.
I.e. when substracting 30 minutes, you get the same time as when _adding_ (+60-30 = ) 30 minutes.
And the same when using DateTimeImmutable. The before-output should be 01:30+01:00.
https://3v4l.org/ZZjvq (DateTimeImmutable)
https://3v4l.org/v3u2v (DateTime)
Btw substracting 60 minutes gives the exact same time again (03:00:00+02:00), while substracting 61
minutes correctly gives "2021-03-28T00:59:00+01:00".
Test script:
---------------
$date = new DateTime('2021-03-28 03:00:00', new
DateTimeZone('Europe/Amsterdam'));
$_30mbefore = (clone $date)->sub(new DateInterval('PT30M'));
$_30mafter = (clone $date)->add(new DateInterval('PT30M'));
var_dump($date->format(DATE_ATOM));
var_dump($_30mbefore->format(DATE_ATOM));
var_dump($_30mafter->format(DATE_ATOM));
Expected result:
----------------
string(25) "2021-03-28T03:00:00+02:00"
string(25) "2021-03-28T01:30:00+01:00" (correct)
string(25) "2021-03-28T03:30:00+02:00"
Actual result:
--------------
string(25) "2021-03-28T03:00:00+02:00"
string(25) "2021-03-28T03:30:00+02:00" (incorrect)
string(25) "2021-03-28T03:30:00+02:00"
------------------------------------------------------------------------
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Edit this bug report at https://bugs.php.net/bug.php?id=80913&edit=1
Thread (6 messages)