我可以在Xcode beta中开发，然后从最新的Xcode GM提交吗？

Question

I have found a lot of questions similar to the one I am asking only ask if you can develop and submit through the beta. This is not what I am looking for an answer to.

I am curious to know if I can develop my application using the Xcode 9 beta, but submit it through Xcode 8?

All programming would be done in the Xcode 9 beta, but when it is time to release the app, I would open the project in Xcode 8 to archive and submit it.

Is this something that would work? If not, why wouldn't it?

Note : I would be using Swift 3.2, not 4.

Answer 1

Submitting with Xcode 8 would be submitting using Swift 3.1 instead of Swift 3.2.

So you can write conditional code like that:

#if swift(>=3.2)
    // code builds for Xcode 9 beta
#else
    // code builds for Xcode 8
#endif

So in practice it gives compatibility to two versions of Xcode, but it's not the same code that compiles.

That's useful for pods and frameworks.

An example where code is required to be different between swift 3.1 and swift 3.2 is when using function swap() ; example of use case :

extension Array {
    mutating func unstableShuffle() {
        for i in stride(from: count - 1, to: 0, by: -1) {
            #if swift(>=3.2)
                swapAt(i, Int(arc4random_uniform(UInt32(i))))
            #else
                swap(&self[i], &self[Int(arc4random_uniform(UInt32(i)))])
            #endif
        }
    }
}

Answer 2

Xcode 9 GM Seed is available now. You can download Xcode 9 without Paid (Premium) Apple Developer Account from below links.

Now you can submit your project developed using Xcode 9 beta to app store using Xcode 9 GM Seed.

Xcode 9 - GM Seed
- (Command Line Tool - Xcode 9 - GM Seed for macOS 10.12)
- (Command Line Tool - Xcode 9 - GM Seed for macOS 10.13)