Today one of my co-workers shared a post he found by Alex King on a Nasty PHP Oddity dealing with dates. The issue was caused by doing date incrementation using the simple expedient of adding or subtracting 86400 seconds to a Unix-style timestamp to move forward or back a day.
This works rather nicely for the most part, except for the day when Daylight Savings Time starts or ends, when a day is an hour longer or shorter.
The predictable response on the OSAF dev mailing list was that the Chandler devs should all be using the Python 'timedelta' to increment or decrement dates. A good idea -- if your language gives you a nice, built-in, error-free way to avoid calculating a bunch of perilous date-related stuff manually, then using it is pretty obviously a Good Thing.
strftime. Sure would be nice to have a