Problem with Zend_Date and ISO_8601 format

Frankly, I'm flummoxed. Can anyone tell me why I would get a failure message with this code?

$date = Zend_Date::now();
$date = $date->getIso();

if(Zend_Date::isDate($date, Zend_Date::ISO_8601)) {
    print('success');
} else {
    print('failure');
}

exit;

It also fails if I just pass in a Zend_Date object.

UPDATE:

a var_dump of the initial $date object looks like this:

object(Zend_Date)#107 (8) { ["_locale:private"]=> string(5) "en_US" ["_fractional:private"]=> int(0) ["_precision:private"]=> int(3) ["_unixTimestamp:private"]=> int(1257508100) ["_timezone:private"]=> string(14) "America/Denver" ["_offset:private"]=> int(25200) ["_syncronised:private"]=> int(0) ["_dst:protected"]=> bool(true) }

And a var_dump of the $date string after calling $date->getIso() looks like this:

string(25) "2009-11-06T04:48:20-07:00"

I am using ZF 1.9.5 on PHP 5.2.8. I am using XAMPP for Windows too if that makes a difference.

I'm running ZF 1.9.4 and PHP 5.2.10 on Ubuntu and was able to reproduce the exact same problem you had. Being the curious type, I did a little digging. Within the code for isDate, a call was made first to getDate within the companion class Zend_Locale_Format. This is wrapped around a try-catch loop, so within the catch portion, I had it dump the exception to stdout. Here's what the exception dump showed me:

exception 'Zend_Locale_Exception' with message 'Unable to parse date
'2009-11-06T04:26:46-08:00' using 'dd mm yy' (d  y)' in /usr/share/php/libzend-framework-php/Zend/Locale/Format.php:995
Stack trace:
#0 /usr/share/php/libzend-framework-php/Zend/Locale/Format.php(1116): Zend_Locale_Format::_parseDate('2009-11-06T04:2...', Array)
#1 /usr/share/php/libzend-framework-php/Zend/Date.php(4583): Zend_Locale_Format::getDate('2009-11-06T04:2...', Array)
#2 {censored}/testbed/test.php(26): Zend_Date::isDate('2009-11-06T04:2...', 'c')
#3 {main}

Doing a var_dump on this exception was a little more telling about those opaque Arrays. Each of them contained the following:

 array(4) {
          ["locale"]=>
          string(5) "en_US"
          ["date_format"]=>
          string(8) "dd mm yy"
          ["format_type"]=>
          string(3) "iso"
          ["fix_date"]=>
          bool(false)
        }

So, date_format doesn't look right at all. It should be "YYYYMMDD'T'hh:mm:ssP," or something like that, in PHP date formatting lingo (I quoted the T, since it's the literal 'T' and not a timezone abbreviation). Granted, PHP just abbreviates it as 'c'.

Strange. So where in the world is it getting this date format? From _getLocalizedToken:

 protected static function _getLocalizedToken($token, $locale)
    {
        switch($token) {
            case self::ISO_8601 :
                return "dd mm yy";
                break;
...

That format looks completely wrong, given the output that ISO_8601 produces.

I would probably check with the people on the appropriate Zend list, but at first glance, this looks like something worthy of a bug report. Maybe they just don't support checks this particular type of date string yet?