Re: [PHP] Strange Result of Datetime::diff

03.04.2017 18:44, Christoph M. Becker пишет:
> On 03.04.2017 at 15:28, Aziz Saleh wrote:
>
>> On Mon, Apr 3, 2017 at 8:39 AM, <[email protected]> wrote:
>>
>>> I'd expect the following script:
>>>
>>> <?php
>>>
>>> $date1 = new DateTime('2017-03-01');
>>> $date2 = new DateTime('2017-04-02');
>>>
>>> $diff = $date1->diff($date2);
>>>
>>> echo "{$diff->m} months and {$diff->d} days.";
>>> ?>
>>>
>>> would print "1 months and 0 days.". But instead it prints "1 months and 3
>>> days." (see https://3v4l.org/RMuUZ).
>>> What is the reason for this behaviour?
>>
>> You sure about that, the above should yield 1 months and 1 days since you
>> have an extra day there:
>>
>> http://sandbox.onlinephpfunctions.com/code/fe7c7d989101ab5e1dd1530d457bfcc7a1cfa8fa
>
> But see <https://3v4l.org/N5fg7>!
>
Please, read this: <https://bugs.php.net/bug.php?id=52480>.
DateTime::diff works with UTC timezone. So, it converts current DateTime 
object to UTC timezone.

If you want to understand how it calculated, do
$date1->setTimeZone(new DateTimeZone('UTC'));
$date2->setTimeZone(new DateTimeZone('UTC'));
and watch what actual values are used in diff.

One of the ways to calculate difference is to use timezone UTC for 
DateTime object
$date1 = new DateTime('2017-03-01', new DateTimeZone('UTC'));
It calculates difference without time shifts and DTS rules.