Fix visibility on import triggering a compile warning

[Wilfred]

Previously, building sourcekit-lsp would produce the following warning:

$ swift build
Building for debugging...
/Users/wilfred/src/sourcekit-lsp/Sources/SKLogging/CustomLogStringConvertible.swift:13:9: warning: package import of 'Foundation' was not used in package declarations
 11 | //===----------------------------------------------------------------------===//
 12 |
 13 | package import Foundation
    |         `- warning: package import of 'Foundation' was not used in package declarations

Remove the visibility modifier, so no warning is produced.

[ahoppen]

Thanks for opening the PR to fix this. Looks good to me.

[ahoppen]

@swift-ci Please test

[Wilfred]

Argh, the package import is needed when you're using the non-darwin logger. I've updated the PR.

[ahoppen]

Thanks ❤️

[ahoppen]

@swift-ci Please test

[ahoppen]

@swift-ci Please test Windows

[ahoppen]

Looks like there are some more import-related errors. Could you take a look at them? If you can’t figure them out, let me know and I can help investigate

[Wilfred]

OK, I've tweaked the conditional to check whether we're on macOS, which seems to fix the build.

I don't understand why the warning only triggered on macOS though. I see InternalImportsByDefault is set in Package.swift.

/home/wilfred/src/sourcekit-lsp/Sources/SKLogging/CustomLogStringConvertible.swift:40:21: error: class cannot be declared package because its superclass is internal
 14 | import Foundation
 15 | #else
 16 | import Foundation
    | `- note: class 'NSObject' imported as 'internal' from 'Foundation' here
 17 | #endif
 18 | 
    :
 38 | /// thus pass this object to OSLog, which just forwards to `description` or
 39 | /// `redactedDescription` of an object that implements `CustomLogStringConvertible`.
 40 | package final class CustomLogStringConvertibleWrapper: NSObject, Sendable {
    |                     |- error: class cannot be declared package because its superclass is internal
    |                     `- note: class 'NSObject' is imported by this file as 'internal' from 'Foundation'

This is the build failure I see on my Linux box, which suggests that the Linux build is treating import Foundation as private import Foundation, whereas the macOS build isn't for some reason. CustomLogStringConvertibleWrapper is still defined on both platforms unless I'm missing something.

TLDR: This fixes the warning and I think should make CI green, although there's some detail I don't understand.

[bnbarham]

I believe the difference here is where NSObject is defined (seems to be Foundation on non-Darwin), though I'm not positive how we end up finding a package-visible-NSObject on macOS 🤔

We could maybe make this:

#if canImport(ObjectiveC)
import Foundation
package import ObjectiveC
#else
package import Foundation
#endif

To make it super obvious, or just:

#if canImport(ObjectiveC)
import Foundation
#else
package import Foundation
#endif

?

[ahoppen]

I like the first proposal with the explicit import to the ObjectiveC module, maybe with a comment that summarises what @bnbarham said above.