Project layout

This is a Tuist based project that presents a behaviour I could not fully explain. I'm pretty sure it dependes on how Binary targets are defined and compiled, and I'm wondering if there is a simple solution (maybe with a build flag)

• Two Swift packages under modules

• Apps with the same code base but different Project.swift defintions

  Swift Packages

  Under the Modules folder are two packages

  • LocalSwiftPackageFlag - a simple pacakge exposing a protocol (MyConfiguration) an enum (SecurityClient) and a pure function (castAndGetAppID). The castAndGetAppID is the testing function. It casts the SecurityClient type into the protocol MyConfiguration type ((SecurityClient.self as? MyConfiguration.Type))
  • LocalSwiftPackageBootstrap - a lean module that conforms the SecurityClient to the MyConfiguration protocol

Note the protocol defines a static propery - and this is where I think the difference of the behaviour I''m going to describe

Applicaitons

Under the Apps folder are 3 applications. The applications run the same code. The difference is in the way the applications are importing modules described above

• AppSPM - under the folder JustWithSPM there is a simple old-school project file that defines and uses the two package using SPM directly
• AppDependencies - under the folder WithDepdendenciesDotSwift there is a simple project file that defines and uses the two package using Dependencies.swift - as external dependenceis
• AppDependencies2 - under the folder WithDepdendenciesDotSwiftConformanceAtTheAppLevel there is a simple project file that defines and uses the two package using Dependencies.swift - as external dependenceis

All the applications are running the same code - calling print("DB: \(String(describing: Flag.castAndGetAppID()))") at the end of the didFinishLaunchingWithOptions of the AppDelegate.

The issue is, for the AppDependencies the casting fails, for the AppSPM the casting succeeds. I added the AppDependencies2 to show that if I move the code from the LocalSwiftPackageBootstrap package to the app level, the casting succeeds.

To run and see the diffrrence:

1. Clone the repo
2. Install Tuist
3. Run tuist install from the root of the repo
4. Run tuist generate from the root of the repo
5. Run the applicaitons and see the console log out put with the DB: prefix