[swift-users] Two Obj-C visible functions no longer overload?

Jordan Rose jordan_rose at apple.com
Tue Aug 9 11:50:22 CDT 2016


It’s always been possing to make arrays of Error, but exposing those arrays back to Objective-C may or may not have worked correctly (as you noticed).

And yes, your solutions are either adding different labels, or using the ‘objc’ attribute to explicitly specify a selector for one or the other.

Jordan


> On Aug 8, 2016, at 16:35, Jon Shier <jon at jonshier.com> wrote:
> 
> Jordan:
> 	Could you expand on allowing making arrays of errors? AFAIK, making arrays of ErrorProtocol/ErrorType/Error has always been possible. And somewhat coincidentally I ran into a runtime issue with the same library, fixed in the latest Swift trunk package, that would result in a crash when attempting to access an array of Errors through an intermediate derived property, but only in Objective-C derived classes. Perhaps that’s related?
> 	In any event, if we wished to maintain Objective-C visibility here, I would expect adding different external labels to fix the issue, right?
> 
> 
> Jon
> 
>> On Aug 8, 2016, at 5:04 PM, Jordan Rose <jordan_rose at apple.com <mailto:jordan_rose at apple.com>> wrote:
>> 
>> I would definitely expect these two to conflict, so if they previously compiled happily I would guess that’s a bug we fixed. The most likely possibility is that we didn’t allow making arrays of errors and now we do.
>> 
>> Jordan
>> 
>> 
>>> On Aug 5, 2016, at 14:57, Jon Shier via swift-users <swift-users at swift.org <mailto:swift-users at swift.org>> wrote:
>>> 
>>> Swifters:
>>> 	I’m attempting to update some library code to beta 4 and I’ve run into something that’s either a bug or a deliberate change. In a class that’s a Foundation.Operation subclass, there are two finish() functions:
>>> 
>>> final func finish(_ receivedErrors: [Error] = []) {
>>>     _finish(receivedErrors, fromCancel: false)
>>> }
>>> 
>>> /// Convenience method to simplify finishing when there is only one error.
>>> final func finish(_ receivedError: Error?) {
>>>     finish(receivedError.map { [$0]} ?? [])
>>> }
>>> 
>>> Prior to beta 4 these functions lived side by side quite happily. In beta 4, however, their existence produces this error:
>>> 
>>> method 'finish' with Objective-C selector 'finish:' conflicts with previous declaration with the same Objective-C selector
>>> 
>>> Now, if I mark one of the functions @nonobjc, it compiles. So is this a bug or change in behavior?
>>> 
>>> 
>>> 
>>> Jon Shier
>>> _______________________________________________
>>> swift-users mailing list
>>> swift-users at swift.org <mailto:swift-users at swift.org>
>>> https://lists.swift.org/mailman/listinfo/swift-users <https://lists.swift.org/mailman/listinfo/swift-users>
>> 
> 

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