module 'ComposableArchitecture' was not compiled for testing

[eimantas]

I added TCA to my application (without adding TCA test support). I can't seem to get the SwiftUI previews working anymore. After pressing "Resume" on the canvas I get the "Build Failed" HUD. Tapping "Diagnostics" gives me this error:

SchemeBuildError: Failed to build the scheme "App"

Build target ComposableArchitectureTestSupport:
note: Set ENABLE_PREVIEWS=NO because SWIFT_OPTIMIZATION_LEVEL=-Owholemodule, expected -Onone (in target 'ComposableArchitectureTestSupport' from project 'swift-composable-architecture')


Compile Swift source files:
/Users/eimantas/Development/DerivedData/App-cvsbxwitwserczdehyykapbndqjo/SourcePackages/checkouts/swift-composable-architecture/Sources/ComposableArchitectureTestSupport/TestStore.swift:4:18: error: module 'ComposableArchitecture' was not compiled for testing
@testable import ComposableArchitecture

I understand this is not the problem with TCA itself, but with either Xcode or my project settings.

I turned off -Owholemodule optimisation in ALL of the targets (the app has a watch app counterpart). I also turned off ENABLE_PREVIEWS. Even with that setting it tells me to turn them off. The project builds and I can run tests, but when it comes to getting the previews - for some reason I can't get it to build.

It's also strange that tests run just fine (because they don't have dependency on TCA's Test Support library) and the app builds. But previews for some reason just don't show up.

I also just checked the settings with vanilla project that contains TCA and it's test support - the build settings are identical which makes me even more confused :(

[stephencelis]

Let's see if anyone else encounters this issue. At the moment we need a way to reproduce to troubleshoot it. Could very well be a gotcha with tooling and maybe we could document the issue and workaround when we know it!

[alexito4]

I just added the library to a new iOS project and previews don't compile anymore. The only error Xcode points to is the Reducer file.

But I don't think this is the issue, it seems like the compiler is trapping somewhere. I see "Command CompileSwift failed with a nonzero exit code" for a lot of files in the library.

The funny thing is compiling and running works just fine, is just when Xcode compiles for previews. ¯_(ツ)_/¯

[stephencelis]

@alexito4 Can you zip the project up and attach it here? Would love to pull it down and troubleshoot.

[marknorgren]

Zip attached with Todos project that has error in the preview.

Xcode Version 11.4.1 (11E503a)

1.	Apple Swift version 5.2.2 (swiftlang-1103.0.32.6 clang-1103.0.32.51)
2.	Running pass 'CallGraph Pass Manager' on module '/Users/marknorgren/Library/Developer/Xcode/DerivedData/Todos-bhgrithytriskqdvxawbbbrvhdxl/Build/Intermediates.noindex/Previews/Todos/Intermediates.noindex/swift-composable-architecture.build/Debug-iphonesimulator/ComposableArchitecture.build/Objects-normal/x86_64/IdentifiedArray.o'.
3.	While splitting coroutine @"$s22ComposableArchitecture15IdentifiedArrayV2idq_Sgx_tciM"
0  swift                    0x000000010f4434ea PrintStackTraceSignalHandler(void*) + 42
1  swift                    0x000000010f442cc0 SignalHandler(int) + 352
2  libsystem_platform.dylib 0x00007fff6679942d _sigtramp + 29
3  swift                    0x000000010fe54000 (anonymous namespace)::DarwinX86AsmBackend::getCompactUnwindRegNum(unsigned int) const::CU32BitRegs + 130378
4  libsystem_c.dylib        0x00007fff6666ea1c abort + 120
5  swift                    0x000000010b197a91 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*)::$_1::__invoke(void*, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, bool) + 1137
6  swift                    0x000000010f3be5c6 llvm::report_fatal_error(llvm::Twine const&, bool) + 278
7  swift                    0x000000010f3be4ab llvm::report_fatal_error(char const*, bool) + 43
8  swift                    0x000000010d2cfdc2 llvm::coro::buildCoroutineFrame(llvm::Function&, llvm::coro::Shape&) + 27394
9  swift                    0x000000010d2d4e1c splitCoroutine(llvm::Function&, llvm::CallGraph&, llvm::CallGraphSCC&) + 9676
10 swift                    0x000000010d2d203d (anonymous namespace)::CoroSplit::runOnSCC(llvm::CallGraphSCC&) + 3165
11 swift                    0x000000010dd6a4b9 (anonymous namespace)::CGPassManager::runOnModule(llvm::Module&) + 2217
12 swift                    0x000000010f2eb503 llvm::legacy::PassManager::run(llvm::Module&) + 1251
13 swift                    0x000000010b3a3f10 swift::performLLVM(swift::IRGenOptions&, swift::DiagnosticEngine*, llvm::sys::SmartMutex<false>*, llvm::GlobalVariable*, llvm::Module*, llvm::TargetMachine*, swift::version::Version const&, llvm::StringRef, swift::UnifiedStatsReporter*) + 7712
14 swift                    0x000000010b1a201b performCompileStepsPostSILGen(swift::CompilerInstance&, swift::CompilerInvocation&, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule> >, bool, llvm::PointerUnion<swift::ModuleDecl*, swift::SourceFile*>, swift::PrimarySpecificPaths const&, bool, int&, swift::FrontendObserver*, swift::UnifiedStatsReporter*) + 12923
15 swift                    0x000000010b19529a swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 48426
16 swift                    0x000000010b10cf53 main + 1283
17 libdyld.dylib            0x00007fff665a07fd start + 1
18 libdyld.dylib            0x0000000000000072 start + 2577791094
error: Abort trap: 6 (in target 'ComposableArchitecture' from project 'swift-composable-architecture')

Todos.zip

[huynguyen]

I've narrowed this down a little and it's somehow related to 4016008#diff-cff665441bd6f271c87862ed5497c3b3R101-R103

It seems that doing anything related to self after the yield causes the crash:
https://gist.github.com/huynguyen/f4e3622531b35d2da68b2b0ade20706d#file-gistfile1-txt-L68-L91

I'm not familiar with the behavior of _modify and yield but commenting out the offending lines enables previews again. Additionally using self after yield on the func above will cause the same kind of error.

I can also upload another example if it helps, but it's just a blank project with the TCA added via swiftPM, not even imported.

[huynguyen]

Maybe the way forward is to go back to the blessed set property observer and take the performance hit for this case?

  public subscript(id id: ID) -> Element? {
    get {
      self.dictionary[id]
    }
    set {
      self.dictionary[id] = newValue
      if self.dictionary[id] == nil {
        self.ids.removeAll(where: { $0 == id })
      }
    }
  }

[klaaspieter]

Adding another data point. It started failing for me after I upgraded to 0.1.1. Downgrading to 0.1.0 solves the issue and makes previews build again.

This is in Xcode 11.4.0.

[buscarini]

Same thing here. I had the same issue, and downgrading to 0.1.0 fixed it.

[alexito4]

@alexito4 Can you zip the project up and attach it here? Would love to pull it down and troubleshoot.

I just sent you a DM with the zip.

[stephencelis]

It seems that doing anything related to self after the yield causes the crash:
https://gist.github.com/huynguyen/f4e3622531b35d2da68b2b0ade20706d#file-gistfile1-txt-L68-L91

Good find!

Maybe the way forward is to go back to the blessed set property observer and take the performance hit for this case?

😔 I think so. It shouldn't be too much of a performance hit, and we can evaluate other routes of optimizing IdentifiedArray in the future.

I'll prepare a fix and a quick 0.1.2 bump, thanks!

[stephencelis]

@eimantas (and everyone experiencing similar issues): could you point your projects towards this branch/commit and confirm that it fixes things? #31

[eimantas]

I appreciate the effort!

I've pointed the SPM to the branch, however it doesn't fix my issue. I still get the same broken build when trying to preview the views.

I wonder if I'm writing some funky UI view 🤔

[alexito4]

could you point your projects towards this branch/commit and confirm that it fixes things? #31

Pointing to master and seems to be working 👌

I've pointed the SPM to the branch, however it doesn't fix my issue. I still get the same broken build when trying to preview the views.

not useful answer I know, but make sure you clean everything and close Xcode. Xcode & previews are quite stubborn 😂