Support dynamic SPM product

[andrii-vysotskyi-cko]

This PR adds a dynamic product to JOSESwift.

[daniel-moh]

Hi @andrii-vysotskyi-cko, thanks for your contribution and apologies for the late response.

Could you clarify a bit on the need for declaring this separate library product? According to SPM documentation, leaving the linking type empty lets SPM decide which one to use—effectively supporting both linkage types. I might be missing something here but, to me, this sounds like there is no need to explicitly declare a separate dynamic-only library product:

Leave this parameter so Swift Package Manager can choose between static or dynamic linking (recommended). If you don’t support both linkage types, use Product.Library.LibraryType.static or Product.Library.LibraryType.dynamic for this parameter.

📚 SPM Docs

[andrii-vysotskyi-cko]

Hey @daniel-moh, thank you for the response.

The use case we are facing is that there is a binary only dynamic framework that is distributed via SPM. This framework depends on JOSESwift, but SPM still links JOSESwift statically so we are forced to vendor our own dynamic copy of framework.

Having an ability to use "dynamic" version of JOSESwift explicitly should solve the problem.

[daniel-moh]

Thanks for the clarification @andrii-vysotskyi-cko. I understand that adding an additional explicit dynamic library product represents the workaround you need, but it does introduce some complexity that feels a bit unconventional to me. I am still wondering why SPM doesn't automatically pick the correct product like it seems to suggest in its docs.

To better understand the specific issue you’re encountering, could you provide a minimal reproducible example or a more detailed explanation of the problem? That way we can rule out that this is a bug in SPM or potentially a misconfiguration on your end and make sure that this is in fact something we need to change on the library end. 🙏