Open Radar

 
Summary:

When the system timezone changes, any NSCalendars previously created with [NSTimeZone localTimeZone] will use the old timezone information instead of the new timezone information when constructing NSDateComponents from NSDates.


Steps to Reproduce:

1. Launch your application in timezone A.
2. Create an NSCalendar.
3. Assign [NSTimeZone localTimeZone] to that calendar.
4. Call components:fromDate: on that calendar. Notice that the information is correct.
5. Background the app.
6. Change the system timezone to timezone B.
7. Bring the app to the foreground.
8. Call components:fromDate: on the calendar created in step (2). Notice that the components are created using timezone A instead of timezone B, even though the [NSTimeZone localTimeZone] instance indeed references the new timezone.


Expected Results:

Because the NSCalendar is using [NSTimeZone localTimeZone], I expect the calendar to automatically use the new timezone when the device timezone changes. Instead, it appears to use the old timezone, thus creating incorrect NSDateComponents from dates. Calling [NSTimeZone resetSystemTimeZone] does not help. NSLogging the calendar timezone after changing the system timezone shows that the localTimeZone has updated correctly. However, components:fromDate: does not work as expected.


Actual Results:

The calendar uses the old timezone information for subsequent calls to components:fromDate:



Regression:

Unknown.


Notes:

Please see the attached sample project that demonstrates this issue.