SPM Resources only in debug configuration

joshpeek · June 30, 2020, 6:38pm

Very excitied to try out SPM resources support!

I was wondering if there was any way to exclude certain assets from the release configuration of a package? I was hoping to exclude my “Preview Assets.xcassets” catalog.

The exclude option seemed promising, but there doesn’t appear to be a way to condition it. I don’t think you can use #if DEBUG in a Package.swift. Is there anything like BuildSettingCondition, but for resources?

mackoj · June 30, 2020, 6:43pm

I have the same question !

NeoNacho · June 30, 2020, 9:36pm

This isn't supported right now, but sounds like an interesting future direction to explore.

joshpeek · July 2, 2020, 3:06pm

Ah, gotcha! Wondering if there’s at least a workaround to suggest for now.

What if these resources were placed in a separate target? Are there any tricks for conditionally linking two targets between dev and release configurations?

SDGGiesbrecht · July 2, 2020, 9:36pm

If you put them in a separate target and forward them with public accessors, then the main target could put #if DEBUG around the import, and use dependencies: [.target(..., condition: .when(configuration: .debug))] in the manifest to prevent it from being included in the product.

joshpeek · July 3, 2020, 1:21am

That sounds useful! But I couldn't seem to get it working. It appears that TargetDependencyCondition only supports .when(.platforms), but no .configuration.

github.com

apple/swift-package-manager/blob/03c10bed07709f6b1b2787433ed15001f7ce433c/Sources/PackageDescription/Target.swift#L768-L788


/// A condition that limits the application of a target's dependency.
public struct TargetDependencyCondition: Encodable {

    private let platforms: [Platform]?

    private init(platforms: [Platform]?) {
        self.platforms = platforms
    }

    /// Creates a target dependency condition.
    ///
    /// - Parameters:
    ///   - platforms: The applicable platforms for this target dependency condition.
    public static func when(
        platforms: [Platform]? = nil
    ) -> TargetDependencyCondition {
        // FIXME: This should be an error, not a precondition.
        precondition(!(platforms == nil))
        return TargetDependencyCondition(platforms: platforms)
    }
}

SDGGiesbrecht · July 3, 2020, 1:42am

Interesting. I hadn’t tried it myself. I copied and pasted from the text of SE‐0273. Maybe its implementation is incomplete? Or it was accepted with revisions that never made it back into the document? @NeoNacho was review manager.

NeoNacho · July 6, 2020, 5:26pm

Yep, it is, only the platform part is implemented. It was incorrectly updated to fully implemented, let me fix that.

NeoNacho · July 6, 2020, 5:29pm

Updated the status to

Partially implemented (Swift 5.3 supports platform conditionals, but not configuration conditionals)

now.

rvenable · November 9, 2020, 9:36pm

When you search the evolution proposals, it still shows up as Implemented: https://apple.github.io/swift-evolution/#?search=Package%20Manager%20Conditional%20Target%20Dependencies
But maybe that can't be fixed?

What is important is - is this feature still being tracked somewhere, or is it falling through the cracks?

CypherPoet · May 3, 2021, 5:37am

Friendly bump.

theMomax · July 23, 2021, 4:54pm

@NeoNacho what is the state on this matter? What is currently blocking implementation?

CypherPoet · August 24, 2021, 2:43pm

This post outlines a use case that I'm also actively seeking: The ability to share stub-like data between tests in a package and Xcode previews in an app -- without having to include that said data in release builds.