andThen operator with Single trait disposes immediately after Completable emits completed event

[lizhiquan]

Short description of the issue:

andThen operator with Single trait disposes immediately after Completable emits completed event.

Expected outcome:

Single should run normally until it emits its own event.

What actually happens:

Single disposes after Completable emit completed event.

Self contained code example that reproduces the issue:

func api() -> Single<[String: AnyObject]> {
    return Single.create { (observer) -> Disposable in
        let url = URL(string: "https://api.github.com/users/phucnm")!
        let task = URLSession.shared.dataTask(with: url, completionHandler: { (data, response, error) in
            do {
                if let data = data {
                    let dict = try JSONSerialization.jsonObject(with: data, options: []) as! [String: AnyObject]
                    observer(.success(dict))
                    print(dict.debugDescription)
                }
            } catch {
                observer(.error(error))
                print(error.localizedDescription)
            }
        })
        task.resume()
        return Disposables.create {
            task.cancel()
        }
    }
}

_ = Completable.empty()
  .andThen(api().debug("api"))
  .debug("result")
  .subscribe()

Result:

2017-07-20 11:56:11.936: result -> subscribed
2017-07-20 11:56:11.938: api -> subscribed
2017-07-20 11:56:11.943: api -> isDisposed

RxSwift/RxCocoa/RxBlocking/RxTest version/commit

3.6.0

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:

  8.3.1

Installation method:

• CocoaPods
• Carthage
• Git submodules

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

[kzaher]

Hi @lizhiquan ,

I've made a fix for those issues. Could you please verify #1348 PR solves your issue?

[lizhiquan]

Hi @kzaher ,
The issue is solved.

Thanks, @kzaher. 😀

[kzaher]

I'm hoping to release a patch release for this and #1344 today.