Work Around for Zend Date DST Bug

Question

I discovered a bug in Zend_Date when setting a time that crosses the DST change.

Here's code that illustrates the problem:

date_default_timezone_set('America/New_York');

echo '<pre>';

// DST BEGINS '2012-03-11 02:00:00' - "Spring Forward"
$a = new Zend_Date('2012-03-11 00:00:00', 'yyyy-MM-dd HH:mm:ss');
$a->setTime('04:00:00', 'HH:mm:ss');
echo $a->toString('yyyy-MM-dd HH:mm:ss', 'iso')
        . ' // expected: 2012-03-11 04:00:00' . PHP_EOL;
$b = new Zend_Date('2012-03-11 04:00:00', 'yyyy-MM-dd HH:mm:ss');
$b->setTime('00:00:00', 'HH:mm:ss');
echo $b->toString('yyyy-MM-dd HH:mm:ss', 'iso')
        . ' // expected: 2012-03-11 00:00:00' . PHP_EOL;

// DST ENDS '2012-11-04 02:00:00' - "Fall Back"
$c = new Zend_Date('2012-11-04 00:00:00', 'yyyy-MM-dd HH:mm:ss');
$c->setTime('04:00:00', 'HH:mm:ss');
echo $c->toString('yyyy-MM-dd HH:mm:ss', 'iso')
        . ' // expected: 2012-11-06 04:00:00' . PHP_EOL;
$d = new Zend_Date('2012-11-04 04:00:00', 'yyyy-MM-dd HH:mm:ss');
$d->setTime('00:00:00', 'HH:mm:ss');
echo $d->toString('yyyy-MM-dd HH:mm:ss', 'iso')
        . ' // expected: 2012-11-06 00:00:00' . PHP_EOL;

echo '</pre>';

Ouputs:

2012-03-11 05:00:00 // expected: 2012-03-11 04:00:00
2012-03-10 23:00:00 // expected: 2012-03-11 00:00:00
2012-11-04 03:00:00 // expected: 2012-11-06 04:00:00
2012-11-04 01:00:00 // expected: 2012-11-06 00:00:00

I need to work around this bug, and I am stumped.

---

SOLUTION

Based on the answer from nerdzila, and research on a bug introduced by his solution, I now have this in my sub-classed Zend_Date:

/**
 * Call the function twice to work around the DST bug
 * http://zendframework.com/issues/browse/ZF-10584
 * https://stackoverflow.com/questions/7181702/work-around-for-zend-date-dst-bug
 * https://stackoverflow.com/questions/8593660/zend-date-dst-bug-test-whether-a-date-is-a-time-change-date
 * TODO: remove this once the bug is fixed
 *
 * @param  string|integer|array|Zend_Date  $time    Time to set
 * @param  string                          $format  OPTIONAL Timeformat for parsing input
 * @param  string|Zend_Locale              $locale  OPTIONAL Locale for parsing input
 * @return My_Date Provides fluid interface
 * @throws Zend_Date_Exception
 */
public function setTime($time, $format = null, $locale = null)
{
    // start time zone juggling so that localtime() returns the correct results
    $tzOrig = date_default_timezone_get();
    date_default_timezone_set($this->getTimezone());

    // capture orignal info
    $timeInfoOrg = localtime($this->getTimestamp(), true);

    // set the time
    parent::setTime($time, $format, $locale);

    // if the dst has changed, perform workaround
    $timeInfoNew = localtime($this->getTimestamp(), true);
    if ((0 < $timeInfoOrg['tm_isdst']) != (0 < $timeInfoNew['tm_isdst'])) {
        // set the time again
        parent::setTime($time, $format, $locale);
        // if the day changed, set it back
        if ($timeInfoOrg['tm_yday'] != $timeInfoNew['tm_yday']) {
            // localtime() year date is zero indexed, add one
            $this->setDayOfYear($timeInfoOrg['tm_yday'] + 1);
        }
    }

    // end time zone juggling
    date_default_timezone_set($tzOrig);

    // fluent
    return $this;
}

I can simply remove it once the bug is fixed.

Answer 1

That's an unfortunate bug. I got around it by calling setTime() twice for each date:

...
$a->setTime('04:00:00', 'HH:mm:ss');
$a->setTime('04:00:00', 'HH:mm:ss');
...
$b->setTime('00:00:00', 'HH:mm:ss');
$b->setTime('00:00:00', 'HH:mm:ss');
...
$c->setTime('04:00:00', 'HH:mm:ss');
$c->setTime('04:00:00', 'HH:mm:ss');
...
$d->setTime('00:00:00', 'HH:mm:ss');
$d->setTime('00:00:00', 'HH:mm:ss');
...

My results:

2012-03-11 04:00:00 // expected: 2012-03-11 04:00:00
2012-03-10 00:00:00 // expected: 2012-03-11 00:00:00
2012-11-04 04:00:00 // expected: 2012-11-04 04:00:00
2012-11-04 00:00:00 // expected: 2012-11-04 00:00:00