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Bug #54145 DateTime->add is not affected by DST changes
Submitted: 2011-03-03 01:51 UTC Modified: 2011-03-03 15:31 UTC
From: giorgio dot liscio at email dot it Assigned:
Status: Not a bug Package: Date/time related
PHP Version: 5.3.5 OS: all?
Private report: No CVE-ID: None
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From: giorgio dot liscio at email dot it
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 [2011-03-03 01:51 UTC] giorgio dot liscio at email dot it 
Description:
------------
hi
when dateinterval walks across a dst change 

$a = DateTime::createFromFormat
(
"d/m/Y H:i:s e",
"03/03/2011 01:38:25 europe/rome"
);

$a = $a->add(new DateInterval("P1M")); // now we have DST in italy

should add +1 hour too, I think, but it doesn't

thank you

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 [2011-03-03 02:03 UTC] giorgio dot liscio at email dot it 
proposed solution:
->add and ->sub methods should internally convert to UTC before add or sub the interval, then should re-set the original timezone
 [2011-03-03 05:28 UTC] dtajchreber@php.net
-Status: Open +Status: Bogus
 [2011-03-03 05:28 UTC] dtajchreber@php.net 
david@copenhagen:~/test$ php -v
PHP 5.3.6-dev (cli) (built: Feb 26 2011 23:29:38) (DEBUG)
Copyright (c) 1997-2011 The PHP Group
Zend Engine v2.3.0, Copyright (c) 1998-2011 Zend Technologies
david@copenhagen:~/test$ cat t.php 
<?php

date_default_timezone_set('America/Chicago');

$d = new DateTime('03-march-2011');
var_dump($d->format('c'));
$d->add(new DateInterval('P1M'));
var_dump($d->format('c'));

date_default_timezone_set('Europe/Rome');

$d = new DateTime('03-march-2011');
var_dump($d->format('c'));
$d->add(new DateInterval('P1M'));
var_dump($d->format('c'));

david@copenhagen:~/test$ php t.php 
string(25) "2011-03-03T00:00:00-06:00"
string(25) "2011-04-03T00:00:00-05:00"
string(25) "2011-03-03T00:00:00+01:00"
string(25) "2011-04-03T00:00:00+02:00"
david@copenhagen:~/test$
 [2011-03-03 15:05 UTC] giorgio dot liscio at email dot it 
so what? in your code this is working, right?
in this case i will investigate on the mine
 [2011-03-03 15:23 UTC] giorgio dot liscio at email dot it 
here is it

with your testcase, using time  too in the constructor, the time itself is not update


date_default_timezone_set('America/Chicago');

$d = new \DateTime('03-march-2011 10:10:10');
var_dump($d->format('c'));
$d->add(new \DateInterval('P1M'));
var_dump($d->format('c'));

date_default_timezone_set('Europe/Rome');

$d = new \DateTime('03-march-2011 10:10:10');
var_dump($d->format('c'));
$d->add(new \DateInterval('P1M'));
var_dump($d->format('c'));
 [2011-03-03 15:31 UTC] derick@php.net 
The time is not supposed to update. One month is a month, not 31 (or 30) * 86400 seconds. You will also see that "P1D" adds one to the day, and does not bother with the hours. A day at the DST change over is simply 25 hours (or 23 hours).
 [2011-03-03 15:49 UTC] giorgio dot liscio at email dot it 
ok, this is right, now I understand
thank you, i'm sorry for bogus!
 
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