This code crashes for me:
php -r 'echo serialize(date_create("2012-10-21 12:30:00 PST")->getTimezone());'

The problem seems to be in this one:

case TIMELIB_ZONETYPE_ABBR:
            ZVAL_STRING(zv, tzobj->tzi.tz->timezone_abbr, 1);

tzobj->tzi.tz doesn't see to have anything useful here.
Please fix and add tests for different zone types, not only one.

So you're absolutely right on that. Thank you for catching my mistake. Over the past month I've gotten the ABBR timezone to work correctly.

I am still working on the OFFSET timezone. Currently we do not have a way to instantiate a DateTimeZone using an offset. I am playing around with creating a way to do this. If that doesn't turn out to be reasonable I think we'll have to do it w/o implementing the OFFSET timezone.

Will this work with microseconds?
Example

<?php
$date = DateTime::createFromFormat('U.u', microtime(true));
var_dump(unserialize(serialize($date))->format('U.u'));

Ping @derickr

@lstrojny I am not sure, but this pull request has to do specifically w/ DateTimeZone objects, not DateTime objects.

Looks good, but misses tests for type 1 and 2 timezone types.

@lonnylot my bad :)

@lonnylot could you please rebase?

@lonnylot ping

@lstrojny Been a tad busy :)

I rebased and made a few other changes (all mentioned in the commit message). All tests passed.

Any chance of this making it into 5.5?

Good for reminding me, I'll merge this bug fix after the
DateTimeImmutable fix that I've been working on.

I've merged it after adding the .c parser files too, but for some odd reason I can't close this PR.

Can someone close the related bug: https://bugs.php.net/bug.php?id=54567

@lonnylot Done (and for the other PR as well) :)