Error when using package manager in Xcode 11.4 beta

[nhatlee]

Short description of the issue:

I create new project for test using RxSwift via Swift package manager . In Xcode project I chose File -> Swift Packages -> Add Package Dependency... to add RxSwift repo. But after Xcode fetch the RxSwift lib successful. I press build and get the error:

ld: warning: Could not find or use auto-linked library 'XCTestSwiftSupport'
ld: warning: Could not find or use auto-linked framework 'XCTest'
Undefined symbols for architecture x86_64:
  "XCTest.XCTAssertEqual<A where A: Swift.Equatable>(_: @autoclosure () throws -> A, _: @autoclosure () throws -> A, _: @autoclosure () -> Swift.String, file: Swift.StaticString, line: Swift.UInt) -> ()", referenced from:
      RxTest.XCTAssertEqual<A where A: Swift.Equatable>(_: [RxSwift.Event<A>], _: [RxSwift.Event<A>], file: Swift.StaticString, line: Swift.UInt) -> () in RxTest.o
      RxTest.XCTAssertEqual<A where A: Swift.Equatable>(_: [RxSwift.SingleEvent<A>], _: [RxSwift.SingleEvent<A>], file: Swift.StaticString, line: Swift.UInt) -> () in RxTest.o
      RxTest.XCTAssertEqual<A where A: Swift.Equatable>(_: [RxSwift.MaybeEvent<A>], _: [RxSwift.MaybeEvent<A>], file: Swift.StaticString, line: Swift.UInt) -> () in RxTest.o
      RxTest.XCTAssertEqual(_: [RxSwift.CompletableEvent], _: [RxSwift.CompletableEvent], file: Swift.StaticString, line: Swift.UInt) -> () in RxTest.o
      RxTest.XCTAssertEqual<A where A: Swift.Equatable>(_: [RxTest.Recorded<RxSwift.Event<A>>], _: [RxTest.Recorded<RxSwift.Event<A>>], file: Swift.StaticString, line: Swift.UInt) -> () in RxTest.o
      RxTest.XCTAssertEqual<A where A: Swift.Equatable>(_: [RxTest.Recorded<RxSwift.Event<A?>>], _: [RxTest.Recorded<RxSwift.Event<A?>>], file: Swift.StaticString, line: Swift.UInt) -> () in RxTest.o
      RxTest.XCTAssertRecordedElements<A where A: Swift.Equatable>(_: [RxTest.Recorded<RxSwift.Event<A>>], _: [A], file: Swift.StaticString, line: Swift.UInt) -> () in RxTest.o
      ...
  "XCTest.XCTFail(_: Swift.String, file: Swift.StaticString, line: Swift.UInt) -> ()", referenced from:
      RxTest.XCTAssertRecordedElements<A where A: Swift.Equatable>(_: [RxTest.Recorded<RxSwift.Event<A>>], _: [A], file: Swift.StaticString, line: Swift.UInt) -> () in RxTest.o
  "__swift_FORCE_LOAD_$_XCTestSwiftSupport", referenced from:
      __swift_FORCE_LOAD_$_XCTestSwiftSupport_$_RxTest in RxTest.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)


Showing All Messages
Could not find or use auto-linked library 'XCTestSwiftSupport'

Could not find or use auto-linked framework 'XCTest'

Undefined symbol: XCTest.XCTAssertEqual<A where A: Swift.Equatable>(_: @autoclosure () throws -> A, _: @autoclosure () throws -> A, _: @autoclosure () -> Swift.String, file: Swift.StaticString, line: Swift.UInt) -> ()

Undefined symbol: XCTest.XCTFail(_: Swift.String, file: Swift.StaticString, line: Swift.UInt) -> ()

Undefined symbol: __swift_FORCE_LOAD_$_XCTestSwiftSupport

Expected outcome:

Expected run success.

What actually happens:

Got the error with above log

RxSwift/RxCocoa/RxBlocking/RxTest version/commit

5.0.1

Platform/Environment

• iOS
• macOS
• tvOS
• watchOS
• playgrounds

How easy is to reproduce? (chances of successful reproduce after running the self contained code)

• easy, 100% repro
• sometimes, 10%-100%
• hard, 2% - 10%
• extremely hard, %0 - 2%

Xcode version:

Xcode 11.4 beta 1

⚠️ Fields below are optional for general issues or in case those questions aren't related to your issue, but filling them out will increase the chances of getting your issue resolved. ⚠️

Installation method:

• CocoaPods
• Carthage
• Git submodules
• Swift Package Manager

I have multiple versions of Xcode installed:
(so we can know if this is a potential cause of your issue)

• yes (which ones)
• no

Level of RxSwift knowledge:
(this is so we can understand your level of knowledge
and formulate the response in an appropriate manner)

• just starting
• I have a small code base
• I have a significant code base

[nhatlee]

I post full logs :
Build target LovePet_2020-02-09T11-24-15.txt

[freak4pc]

Hey there :)
If it works on 11.4 (which is in beta) and doesn't have issues on 11.3, this is likely a bug inside SPM itself.

We only have so much capacity so we can't spend the time fixing specific package manager bugs, at least not until 11.4 goes out of beta.

If you have a PR that might fix this issue, I'm happy to review and merge it.

Thanks !

[freak4pc]

@nhatlee Do you have additional feedback on this issue?

[nhatlee]

I don't have time to investigating this issue since I posted it. I will try to find out when have time.

[nhatlee]

After some trying. It seem the issue related to problem with linking XCTest. Move RxTest from target to testTarget fixed the issue. The change for Package file like this commit: https://github.com/nhatlee/RxSwift/commit/19df574ac70e4ce3f758a807b8541097c7397398

[freak4pc]

It shouldn't be a testTarget, the reason it's working for you is that you removed all of its dependencies

There's an entire discussion around this here: https://twitter.com/freak4pc/status/1233560587176681472

[freak4pc]

From discussions in the SPM slack this seems like a bug.
I've reported it here: https://bugs.swift.org/browse/SR-12303
And also filed a feedback: FB7608638

[truizlop]

I have the same issue after updating to Xcode 11.4 (stable version, not beta). Any way to solve/workaround this?

[freak4pc]

The workaround is to wrap all of your Rx dependencies in one product inside your own app, which would remove the duplications. I'm not sure this would work for RxTest and RxBloccking, though:

let package = Package(
  name: "Rx Wrapper",
  products: [
    .library(name: "Rx", targets: ["Rx"]),
    .library(name: "RxTesting", targets: ["RxTesting"])
  ],
  dependencies: [
    .package(
      url: "https://github.com/ReactiveX/RxSwift.git",
      .upToNextMajor(from: "5.0.0")
    )
  ],
  targets: [
    .target(
      name: "Rx",
      dependencies: ["RxSwift" , "RxCocoa", "RxRelay"]
    ),
    .target(
      name: "RxTesting",
      dependencies: ["RxTest", "RxBlocking"]
    )
  ]

I'm not sure this will work for the test target, as mentioned above.
This workaround was added in the SPM Slack by @DevAndArtist, but I hope Apple will provide an actual solution at some point:

RxSPM_Mod.zip

[antranapp]

I have a similar problem now with Xcode 11.4.1

I can see now, if I integrate RxSwift using SPM, SPM will built RxSwift as a static library:

I could workaround the issue by forcing SPM to build RxSwift as a dynamic framework in my fork: antranapp@722615a

Is there any reason that we are not building RxSwift as a dynamic library by default?

[freak4pc]

@antranapp From the tests I've ran it only solves half of the issues. Tests still don't run.

There's a long discussion in the SPM slack around this, and generally, it's an "open bug" . What we might have to do is basically not allow installing RxTest and RxBlocking via SPM until Apple solves this, and that should mostly solve it, I believe.