SE-0403: Package Manager Mixed Language Target Support

[ncooke3 (Nick Cooke)]

@benrimmington

In the "Motivation" section, when discussing workarounds:

binary dependencies are only available on Apple platforms

but this is also a limitation of your proposed solution?

Yes, it is a limitation of the proposed solution. The reason was that Swift targets do not emit the generated ObjC header when not running on Darwin. This still seems true on main:

apple/swift-package-manager/blob/2054492c13abdc03a2a74233eef496f6565fd2b2/Sources/Build/BuildDescription/SwiftTargetBuildDescription.swift#L732-L735

I realize now however with the added goal of supporting C++ interop in this proposal, this may need to be adjusted so that the limitation only affects targets that mix only Swift and Objective-C?

cc: @compnerd

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@benrimmington

@ncooke3

Hi @benrimmington, just to confirm, the question relates to enabling a package plugin to process a mixed language target? If so, it is something I had not considered, and will look into. Depending on what this entails, I think it may make sense to either include it in this proposal's scope, or pursue it in a follow-up to this proposal.

I think a new MixedSourceModuleTarget type would be needed, but otherwise PackagePlugin support might be mentioned in the "Future Directions" section.

Agreed. With the review period closing, I'm leaning towards adding it to the "Future Directions" section. But, I have begun experimenting with it, so I'll update this post at EOD with a more informed comment here.

edit: I'll add it to the "Future Directions" section in the interest of time.