[swift-users] Double pointer in ObjC function signature importing incorrectly in Swift 3?

[Jordan Rose]

C represents pointers the other way around; that declaration says only the outer pointer is nullable. There are two things going on here:

- Swift 2 made all pointers implicitly nullable, without using an optional type. Swift 3 makes that explicit.
- Swift 2 had a bug that assumed that all pointers-to-references were optional, instead of just those without nullability annotations. Swift 3 "fixes" that…but that reveals places where headers used _Nonnull to mean "always produces a nonnull pointer", forgetting that it also applies to input.

If this is an API in CloudKit itself, please file a Radar at bugreport.apple.com. If it's a third-party library built on CloudKit, you'll have to report the issue to them.

Sorry for the trouble!
Jordan


> On Sep 20, 2016, at 10:32, Michael Gardner via swift-users <swift-users at swift.org> wrote:
> 
> I'm using an Objective-C library that has me provide a callback that takes a double-pointer parameter like this, where only the inner pointer is nullable:
> 
> CKRecord *_Nonnull *_Nullable inOutRecordPtr
> 
> Swift 2 imported this as an AutoreleasingUnsafeMutablePointer<CKRecord?>, as expected. However, Swift 3 is importing it as AutoreleasingUnsafeMutablePointer<CKRecord>?, which breaks the library's API since there's no way to return a new record.
> 
> Is this a Swift 3 bug, or am I missing something?
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