How can I add a Custom Intent which requires iOS 12 while targeting an older iOS version?

Question

I am trying to add a Custom Intent to support Siri Shortcuts in my app which targets iOS 10.3. Xcode automatically generates the intent classes and protocols, but all the generated classes and protocols have the attribute below:

@available(iOS 12.0, watchOS 5.0, *)

I am aware of #available(...) but it is not used for including or excluding code at compile time, so I am not sure how to go about adding a Custom Intent if my target is set to pre-iOS 12.

In the snippet below, MyIntentHandling and MyIntentResponse are generated automatically by Xcode. However, there is no way to use #available here.

public class MyIntentHandler: NSObject, MyIntentHandling {

    func confirm(intent: MyIntent, completion: @escaping (MyIntentResponse) -> Void) { ... }

    func handle(intent: MyEntryIntent, completion: @escaping (MyIntentResponse) -> Void) { ... }
}

Does anyone have a good solution?

Answer 1

No,

#available

is for compile and runtime checks.

The Swift compiler checks at compile time, that no methods are called that are not supported for your chosen deployment target and forces you to use #available conditions. So, since Xcode 9 it's much safer to support older iOS deployment targets and use new features.

At runtime, there is a check, if an #available condition matches your current running iOS version and it will execute only the matching code.

So, you are safe, with your additional intent support.