# Compiling a dynamic framework with a statically linked library creates dependencies in ".swiftmodule" file

**URL:** <https://forums.swift.org/t/compiling-a-dynamic-framework-with-a-statically-linked-library-creates-dependencies-in-swiftmodule-file/22708>\
**Category:** Using Swift\
**Tags:** compiler\
**Created:** [April 5, 2019, 6:36pm UTC](https://forums.swift.org/t/compiling-a-dynamic-framework-with-a-statically-linked-library-creates-dependencies-in-swiftmodule-file/22708 "2019-04-05T18:36:50Z")\
**Posts on this page:** 1\
**Showing post:** 1

<div class="post-metadata">

**Author:** ![ylorn](https://avatars.discourse-cdn.com/v4/letter/y/13edae/32.png) [@ylorn](https://forums.swift.org/u/ylorn)\
**Post date:** [April 5, 2019, 6:36pm UTC](https://forums.swift.org/t/compiling-a-dynamic-framework-with-a-statically-linked-library-creates-dependencies-in-swiftmodule-file/22708/1 "2019-04-05T18:36:50Z")

</div>

Steps to reproduce:

1. Create a new project in Xcode with template **Cocoa Touch Framework** , and name it **TestFramework**.
2. Add another target in this project with template **Cocoa Touch Static Library** , and name it **TestLibrary**.
3. In the auto-generated file **TestLibrary.swift** , add a public interface like:

```swift
    public struct TestLibrary {
        public init() { }
        public let name = "static library"
    }

```

1. In target **TestFramework** , link **libTestLibrary.a**.
2. In target **TestFramework** , create a new file with the name **TestFramework.swift**.
3. In **TestFramework.swift** , import **TestLibrary** and use the API it provides without exposing any symbol in public, like

```swift
    import TestLibrary
    public struct TestFramework {
        public init() { }
        public let library = TestLibrary().name
    }

```

1. Build target **TestFramework** , and locate the product **TestFramework.framework**.
2. Create a new project in Xcode with template **Single View Application** , and name it **TestApplication**.
3. Drag the **TestFramework.framework** from step 7 into the **Embedded Binaries** build phase of **TestApplication**.
4. In the file **AppDelegate.swift** of **TestApplication** , import **TestFramework** like

```swift
    import UIKit
    import TestFramework

```

1. Run the app.
2. At the line where **TestFramework** is imported, an error is prompted:

> ❗ Missing required module 'TestLibrary'

1. If you command-click on that `import TestFramework`, Xcode will generate the public interfaces of **TestFramework** , and it shows as:

```swift
    import Foundation
    import SwiftOnoneSupport
    import TestFramework
    import TestFramework.Swift
    import TestLibrary
    import UIKit
    ...

```

So this is where I got confused.

**TestLibrary** is statically linked with **TestFramework** , which means the binary of **TestFramework** has all the symbols from **TestLibrary**. Plus, **TestFramework** is not exposing any APIs from **TestLibrary** , but only using them. This means **TestFramework** is fully functional on its own regardless of **TestLibrary** being presented or not.

So why the **.swiftmodule** file of **TestFramework** creates an additional (probably unnecessary) dependency on **TestLibrary**?

As a result, when a user uses **TestFramework** to build an app, the app won't be able to compile because it can not find the **TestLibrary** , but it can run perfectly because it actually does not use **TestLibrary** directly if we can somehow bypass that dependency check.

So I am wondering if there is a way to remove a dependency from **.swiftmodule** file?  
Or is there any compile/link flag I can pass in to prevent it generates any unnecessary dependency?

Just found another similar description of this problem while I was searching through the internet for a solution:  
[https://gist.github.com/briancroom/5d0f1b966fa9ef0ae4950e97f9d76f77](https://gist.github.com/briancroom/5d0f1b966fa9ef0ae4950e97f9d76f77)

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