ZF-11354: Zend_Dates adds months differently

Issue Type:
Bug
Created:
2011-05-10T07:59:02.000+0000
Last Updated:
2011-05-27T12:47:13.000+0000
Status:
Open
Fix version(s):
    Reporter:
    Stephan van der Horn (stephan88)
    Assignee:
    Thomas Weidner (thomas)
    Tags:
    • Zend_Date
    • add
    • month
    • zend_date
    Related issues:
    Attachments:

    Description

    I found a bug in Zend_Date where months get added differently when you add one month twelve times compared to adding three months four times (for example). I think the code below speaks for itself.

    The PHP code:

    
$date = new Zend_Date(1269900000);
for($i = 0; $i < 12; $i++) {
    $date->add(1, Zend_Date::MONTH);
}
echo "12 x 1 = ".$date->get(Zend_Date::ISO_8601)."
    ";

$date = new Zend_Date(1269900000);
for($i = 0; $i < 4; $i++) {
    $date->add(3, Zend_Date::MONTH);
}
echo "4 x 3 = ".$date->get(Zend_Date::ISO_8601)."
    ";

$date = new Zend_Date(1269900000);
$date->add(12, Zend_Date::MONTH);
echo "1 x 12 = ".$date->get(Zend_Date::ISO_8601);

    Result:

     
12 x 1 = 2011-03-28T00:00:00+02:00
4 x 3 = 2011-03-30T00:00:00+02:00
1 x 12 = 2011-03-30T00:00:00+02:00

    Does anyone know a solution for this problem?

    Comments

    Posted by Andrey Shevchenko (distdev) on 2011-05-27T12:47:13.000+0000

    It's not a bug, because on 11th iteration you have February 28th (according to start date - 30th and option extend_month == false). So, on next iteration you have March, 28th. I would suggest to replace your code smth like this:

    
$monthCount = 0;
for($i = 0; $i < 12; $i++) {
    $monthCount++;
}
$date->add($monthCount, Zend_Date::MONTH);