I encounter this problem as well, Xcode 12 beta 2. Already posted a bug report. My message in the debugger window: 2020-07-19 08:57:47.984596+0200 ***[1905:104396] libMobileGestalt MobileGestaltCache.c:38: No persisted cache on this platform. Cannot create Swift scratch context (couldn't load the Swift stdlib)(lldb) 

I'm struggling with a similar problem and the same error. Is there some "good practice" how a persistent store for SwiftUI 2.0 previews should be set up? [Edit: Oops, this refers to the error post below from sheeley...]

Thanks, GuiDev, this fixed the problem for me.

Nearly the same problem here, just saying "not configured for the build action". Everything is set up as required, but xcodebuild throws an error, reproducibly on local as well as on Xcode Cloud. I have no clue how to proceed to get more details about the reason for the error. Xcode Version 14.0 beta (14A5228q). XX01 git:(develop) /Applications/Xcode-beta.app/Contents/Developer/usr/bin/xcodebuild -resolvePackageDependencies -workspace ./XX-Workspace.xcworkspace -scheme ***.v3 -derivedDataPath ./DerivedData -verbose                                                       git:(develop|)  2022-06-16 08:35:57.930 xcodebuild[4780:8362340] [MT] DVTSDK: Warning: SDK path collision for path '<DVTFilePath:0x600002d3c850:'/Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX13.sdk'>': SDK with name 'macosx13.0' being superseded by SDK with 'macosx13.0'. Command line invocation: /Applications/Xcode-beta.app/Contents/Developer/usr/bin/xcodebuild -resolvePackageDependencies -workspace ./XX-Workspace.xcworkspace -scheme ***.v3 -derivedDataPath ./DerivedData -verbose User defaults from command line: IDEDerivedDataPathOverride = /Users/***/Development/analyse/XX01/DerivedData IDEPackageSupportUseBuiltinSCM = YES 2022-06-16 08:35:58.405 xcodebuild[4780:8362370] nil host used in call to allowsSpecificHTTPSCertificateForHost 2022-06-16 08:35:58.405 xcodebuild[4780:8362370] nil host used in call to allowsAnyHTTPSCertificateForHost: Resolve Package Graph Resolved source packages:   swift-collections: https://github.com/apple/swift-collections @ 1.0.2   SwiftDate: https://github.com/malcommac/SwiftDate.git @ master   xctest-dynamic-overlay: https://github.com/pointfreeco/xctest-dynamic-overlay @ 0.2.1   combine-schedulers: https://github.com/pointfreeco/combine-schedulers @ 0.5.3   swift-identified-collections: https://github.com/pointfreeco/swift-identified-collections @ 0.4.0   swift-composable-architecture: https://github.com/pointfreeco/swift-composable-architecture.git @ main   swift-custom-dump: https://github.com/pointfreeco/swift-custom-dump @ 0.5.0   swift-case-paths: https://github.com/pointfreeco/swift-case-paths @ 0.9.0 2022-06-16 08:35:58.920 xcodebuild[4780:8362340] Writing error result bundle to /var/folders/wy/8nsfjsyn51zgcdhmc36wjjmdls2q5t/T/ResultBundle_2022-16-06_08-35-0058.xcresult xcodebuild: error: Scheme ***.v3 is not currently configured for the build action.

Well, the error occurred again between Parent and DateSpec. So, the workaround did not help. It seems that the relationship itself raises the problem.

Is it possible that the relationship MUST be an optional?

Yes, I have the same problem using #Preview. No idea, why - and other sources (there are really few currently) did not help me on. Xcode Version 15.0 beta 8 (15A5229m).