Cannot use conformance of 'Never' to 'TestScoping' here; 'Testing' has been imported as implementation-only in SnapshotsTestTrait.swift

[legoesbenr]

We have successfully been using the framework for snapshot testing for a long time.
This morning all our Xcode Cloud build has started failing with the error:

Cannot use conformance of 'Never' to 'TestScoping' here; 'Testing' has been imported as implementation-only
SnapshotsTestTrait.swift:37

This appears to be a problem with the implemenation-only import in that file.

#if canImport(Testing)
  // NB: We are importing only the implementation of Testing because that framework is not available
  //     in Xcode UI test targets.
  @_implementationOnly import Testing

  @_spi(Experimental)
  extension Trait where Self == _SnapshotsTestTrait {
    /// Configure snapshot testing in a suite or test.
    ///
    /// - Parameters:
    ///   - record: The record mode of the test.
    ///   - diffTool: The diff tool to use in failure messages.
    public static func snapshots(
      record: SnapshotTestingConfiguration.Record? = nil,
      diffTool: SnapshotTestingConfiguration.DiffTool? = nil
    ) -> Self {
      _SnapshotsTestTrait(
        configuration: SnapshotTestingConfiguration(
          record: record,
          diffTool: diffTool
        )
      )
    }

    /// Configure snapshot testing in a suite or test.
    ///
    /// - Parameter configuration: The configuration to use.
    public static func snapshots(
      _ configuration: SnapshotTestingConfiguration
    ) -> Self {
      _SnapshotsTestTrait(configuration: configuration)
    }
  }

  /// A type representing the configuration of snapshot testing.
  @_spi(Experimental)
  public struct _SnapshotsTestTrait: SuiteTrait, TestTrait {
    public let isRecursive = true
    let configuration: SnapshotTestingConfiguration

    // public func execute(
    //   _ function: @escaping () async throws -> Void,
    //   for test: Test,
    //   testCase: Test.Case?
    // ) async throws {
    //   try await withSnapshotTesting(
    //     record: configuration.record,
    //     diffTool: configuration.diffTool
    //   ) {
    //     try await function()
    //   }
    // }
  }
#endif

Tests has run perfectly up to now and they work locally. So it appears to be a change in Xcode Cloud.

Here's the command Xcode Cloud uses to tune tests:

Run command: 'xcodebuild build-for-testing -scheme 'AM Operator' -project '/Volumes/workspace/repository/OperatorApp/AM-Operator-App/AM Operator.xcodeproj' -destination 'platform=iOS Simulator,id=40FDE0C9-320B-4030-AB16-39F7EB933F43' -testProductsPath /Volumes/workspace/TestProducts.xctestproducts -derivedDataPath /Volumes/workspace/DerivedData -resultBundleVersion 3 -resultBundlePath /Volumes/workspace/resultbundle.xcresult -resultStreamPath /Volumes/workspace/tmp/resultBundleStream45efeb29-8273-490a-be53-e173056c70e6.json -IDEPostProgressNotifications=YES CODE_SIGN_IDENTITY=- AD_HOC_CODE_SIGNING_ALLOWED=YES COMPILER_INDEX_STORE_ENABLE=NO -hideShellScriptEnvironment'

Error: Command exited with non-zero exit-code: 65

I can see 66 unmerged pull requests and 116 reported issues. Is this library dead?

[mbrandonw]

Hi @legoesbenr, what version of SnapshotTesting are you using? There hasn't been an @_implementationOnly in the source since version 1.17.6, released 6 months ago.

I can see 66 unmerged pull requests and 116 reported issues. Is this library dead?

We just had a release yesterday and have consistently updated the library to support new features of Swift and the ecosystem (such as the native Swift Testing framework). Most of those issues are not actual issues with the library, and instead should be discussions, and most of those PR's should be closed. It takes time to manage an open source library, and we have an entire ecosystem of libraries to support. This particular library tends to generate the most noise due to its nature, and so we do not keep up with tending the issues/PRs as much as our other libraries.

Since I don't believe this is an issue with the library I am going to convert it to a discussion. Please feel free to continue the conversation over there!

[legoesbenr]

We're using version 1.17.5, so that might explain it.
Just updated to latest and that fixed it.

Thanks for the response.