> On 5 Oct 2016, at 16:48, Alex Blewitt via swift-users <swift-us...@swift.org> 
> wrote:
> 
> 
>> On 4 Oct 2016, at 20:10, Jason Ji via swift-users <swift-us...@swift.org 
>> <mailto:swift-us...@swift.org>> wrote:
>> 
>> Hello,
>> 
>> I'm having an issue with (NS)Calendar on Linux which I think is a bug, but I 
>> just wanted to check first if it was just me or if this is indeed a bug. 
>> I've filed a bug report here, just in case: 
>> https://bugs.swift.org/browse/SR-2846 <https://bugs.swift.org/browse/SR-2846>
>> 
>> In short, Calendar has a method date(byAdding:to:wrappingComponents:) which 
>> returns a new date which is the result of date arithmetic on the passed-in 
>> date. It works fine on El Capitan, but doesn't seem to work properly on 
>> Ubuntu 14.04. Below is some sample code:
>> 
>> import Foundation
>> 
>> let today = Date()
>> let diffComponents = DateComponents(day: -1)
>> let newDate = Calendar.current.date(byAdding: diffComponents, to: today)     
>>         //returns nil
>> 
>> I've tried this in the swift REPL on Ubuntu 14.04 with both Swift 
>> 3.0-RELEASE, and the latest snapshot (October 2).
>> 
>> If anyone else could try this out as a sanity check for me, that would be 
>> great - I'd be happy to be embarrassed that I've done something wrong.
> 
> It's worth explicitly specifying a calendar (so that it rules out any 
> environmental setup) -- for example, Calendar(identifier:.gregorian). 
> However, I see 'nil' as well as the return result for this operation, so it 
> could be a bug.

I think the bug is here:

https://github.com/apple/swift-corelibs-foundation/blob/master/Foundation/NSCalendar.swift#L464
 
<https://github.com/apple/swift-corelibs-foundation/blob/master/Foundation/NSCalendar.swift#L464>

        _convert(comps.isLeapMonth, type: "L", vector: &vector, compDesc: 
&compDesc)


The leap month is defined with a capital letter here, but a lower-case letter 
when it's decoded:

https://github.com/apple/swift-corelibs-foundation/blob/338f4bf3a89c75a0420b49f5701466e106af02b5/CoreFoundation/Locale.subproj/CFCalendar.c#L423
 
<https://github.com/apple/swift-corelibs-foundation/blob/338f4bf3a89c75a0420b49f5701466e106af02b5/CoreFoundation/Locale.subproj/CFCalendar.c#L423>

    case 'l': return UCAL_IS_LEAP_MONTH;


The lower-case l should be the correct version so this probably needs to be 
changed here. In addition, there are optional-of-bool issues here; the 
'comps.isLeapMonth' is a boolean value, which means it attempts to roll forward 
the leap month (which doesn't make sense). I think the error was introduced 
here, although it didn't help that the capitalisation was also wrong at the 
time:

https://github.com/apple/swift-corelibs-foundation/commit/d3300b7118924d6ad8ba411d317f33eade854bc5
 
<https://github.com/apple/swift-corelibs-foundation/commit/d3300b7118924d6ad8ba411d317f33eade854bc5>
 

Alex

_______________________________________________
swift-corelibs-dev mailing list
swift-corelibs-dev@swift.org
https://lists.swift.org/mailman/listinfo/swift-corelibs-dev

Reply via email to