Swift Package Manager "Undefined symbols for architecture x86_64" from command line

Question

I have an application using Swift Package Manager that runs from the command line and is tested using Swiftest. I am not using Xcode and this is my first Swift project so I don't know how to get out of this error.

I am trying to remove a dependency that I am no longer using. My Package.swift file looks like this:

import PackageDescription

let package = Package(
    name: "MyApplication",
    targets: [
        Target(name: "Target1"),
        Target(name: "Target2", dependencies: ["Target1"]),
        Target(name: "Application", dependencies: ["Target2"]),
        Target(name: "Specs", dependencies: ["Target1", "Target2"]),
    ],
    dependencies: [
        .Package(url: (test package))
    ]
)

And I want to eliminate the "Target1" dependency from "Target2". I am getting this error:

Linking Application
Undefined symbols for architecture x86_64:
  "__TFC10Target1CfT_S0_", referenced from:
      _main in main.swift.o
  "__TMaC10Target1", referenced from:
      _main in main.swift.o
ld: symbol(s) not found for architecture x86_64

All of the solutions I have seen for this error are in reference to Xcode, so I am honestly not even sure where to look for this. Target1 file is not used or referenced anywhere in Target2 file. Here is the design of the application:

├── Package.swift
├── README.md
└── Sources
    ├── Application
    │   └── main.swift
    ├── Target1
    │   ├── Model1.swift
    │   └── Model2.swift
    ├── Target2
    │   ├── Model3.swift
    │   └── View.swift
    └── Specs
        ├── main.swift
        ├── Model1Spec.swift
        ├── Model2Spec.swift
        └── Model3Spec.swift

my main.swift file in the application is the runner. Here is the only place where the two files connect, as I am injecting the return value of a Target1 class's function into the new instance of a Target2 class. This is probably more information than you need.

Anyway, why is this happening? Why do I need to maintain that dependency in Package.swift to something that I am not actually depending on?

Thanks for your help and let me know if you need more info.

Answer 1

You are using Target 1 from Application, and that's what the error is complaining about. Application depends on Target 2 (which currently depends on Target 1 in your supplied Package.swift). If you have removed that then Application won't be able to use anything from Target 1.