“Undefined symbols for architecture arm64:” for function in swift in tests

Question

I have two targets in my Swift project:

1. app
2. tests

There is a function in app target that is not used anywhere in the app, but it is used in tests. As a result I get build error: Undefined symbols for architecture arm64: . It says that the function is undefined and it is referenced from tests.

It looks like compiler removes this unused function from app.

Question: How to make unused function included in the app build?

Note: I do not want to add app's source file to Compile Sources of the test target. I prefer marking app's functions as public and then import the app module in tests instead.

Current (imperfect) solution

Here is how I currently make it build functions which are unused in the app. This way I can use them in tests.

class IncludeUnusedHack {
  init() {
    if NSDate.date().timeIntervalSinceNow > 10_000_000 {
      MyClass.unusedFunctionOne()
      MyClass.unusedFunctionTwo()
    }
  }
}

class AppDelegate: UIResponder, UIApplicationDelegate {

  let unusedHack = IncludeUnusedHack()
  ...
}

Answer 1

我也遇到过这样的问题，然后我通过关闭一个选项解决了。

app(in TARGETS) > Build Settings > Linking > Dead Code Stripping

Answer 2

I believe this is a bug in Xcode up through 6.1 Beta 2. It looks like Xcode 6.1 Beta 3 fixes it though (released today, 9/29). From the release notes:

Testing

• Dead code stripping no longer removes public declarations from Swift application targets which are needed by unit testing. (18173029)