我如何继续使用Swift 2.3，而不是3.0，Xcode更新，无法再构建

Question

I am developing an app with 20+ framework dependencies and not all of them are on 3.0 yet. So I want to keep using Swift 2.3. However, after updating my Xcode to 8.0, I can no longer build my app. It fails with the following error:

“Use Legacy Swift Language Version” (SWIFT_VERSION) is required to be configured correctly for targets which use Swift. Use the [Edit > Convert > To Current Swift Syntax…] menu to choose a Swift version or use the Build Settings editor to configure the build setting directly.

I don't want to convert the whole project to 3.0 yet.

So my question is how do I keep everything same after Xcode 8.0 update?

Answer 1

In case you want to use Swift 2.3 you should go to Build Settings -> Use Legacy Swift Language Version -> YES this will help you to achieve it. after building the app, there will be minor syntax issues. After fixing (not so hard) it will go as usual

Answer 2

You might want to read this article: https://swift.org/migration-guide/ or more specifically section Using Carthage/CocoaPods Projects .

I guess you could choose Include the source code of the project in your Xcode workspace approach. This essentially means that you keep all your code in Swift 2.3 and make a snapshot of all or some external Frameworks referenced as Pods that are not Swift 3.0 ready.