Async.background reports/uses queues other than background

[damonjones]

I made a new Swift project (single view controller) and added Async.swift file. I used the following sample code in my viewDidLoad:

Async.background {
    println("A: This is run on the \(qos_class_self().description) (expected \(QOS_CLASS_BACKGROUND.description))")
}.main {
    println("B: This is run on the \(qos_class_self().description) (expected \(qos_class_main().description)), after the previous block")
}

Running the project multiple times, the results I get are either:

A: This is run on the User Initiated (expected Background)
B: This is run on the Main (expected Main), after the previous block

Or:

A: This is run on the Main (expected Background)
B: This is run on the Main (expected Main), after the previous block

Never do I get the first block reporting that it is running on the background queue.

Xcode 6.1.1 (6A2008a)

[damonjones]

I also opened the AsyncExample project and ran the iOS tests:

[duemunk]

Did you run in simulator?

[damonjones]

Yes.

[damonjones]

I just ran it on a device and the tests passed. Did I miss somewhere where it said that this doesn't work with the simulator?

[pigeondev2]

Possibly relevant: http://stackoverflow.com/a/5172968/3409110

[pigeondev2]

From my own findings: I would like to believe that the simulator is not capable of running multithreaded code, but the problem I have with that, is that if normal GCD works in the simulator and Async doesn't. This sounds like a fixable problem to me. @duemunk: Maybe you should add this discovery to the README to save people some time until the bug is fixed. Just my $0.02

[duemunk]

@istx25 If you can make GCD work in these cases where Async doesn't, please let me know. I think GCD works fine with the pre iOS 8 queue classes, but not with the new ones e.g. DISPATCH_QUEUE_PRIORITY_BACKGROUND.
@damonjones I don't know if it's in the Readme, but it has been a Github issue before #13. I'll update the ready :)

[duemunk]

Added to readme as of bf2983e.
@istx25 If you find anything, please just comment on this issue even though it's closed. Or even better. Make a gist and add a reference to it in the readme under Known Bugs :)

[tciuro]

FWIW, all tests pass fine with the latest (public) version of Xcode: 9.4 (9F1027a)