BlockingObservable.single() should not return an Optional

[skerkewitz]

BlockingObservable.single() should not return an Optional:

I recently started to use BlockingObservable.single() in my unit tests and was wondering why it returns an Optional. If you look into the actual implementation it looks to me that it is not possible for the implementation to return an Optional. Because in that case the implementation would throw a RxError.

I had a quick chat on the RxSwift Slack channel and and a brief look my concern was confirmed.

Expected outcome:

I expect either to have a valid non optional result or an error was thrown.

What actually happens:

Currently my result has to be an optional and I either have to add a force unwrap or a guard statement in my test cases.

Self contained code example that reproduces the issue:

        let result = Observable.just(0.0).toBlocking(timeout: 10).single()

RxSwift/RxCocoa/RxBlocking/RxTest version/commit

RxSwift 4.0.0

Platform/Environment

• iOS
• macOS
• tvOS
• watchOS
• playgrounds

Only use iOS but it should be the same for all platforms.

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%

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 @skerkewitz ,

we've changed the implementation but the interface unfortunately remained the same.
It was an oversight.

[skerkewitz]

Nice, thanks. 👍