MPSC race condition in Queue

[djspiewak]

    "offer/take with a single consumer and high contention" in real {
      constructor(8) flatMap { q =>
        val offerer = List.fill(8)(List.fill(8)(0)).parTraverse_(_.traverse(q.offer(_)))
        offerer.start *> 0.until(8 * 8).toList
          .traverse_(_ => q.take)
          .timeoutTo(8.seconds, IO(false must beTrue))
          .replicateA_(1000)
          .as(ok)
      }
    }

The weirdest bit is this hangs both with the Concurrent version and the new Async one.

[durban]

I think the deadlock in this test is due to offerer not being replicateA_'d. At least this version seems to work:

    constructor(8) flatMap { q =>
      val offerer = List.fill(8)(List.fill(8)(0)).parTraverse_(_.traverse(q.offer(_)))
      val taker = 0.until(8 * 8).toList.traverse_(_ => q.take).timeoutTo(8.seconds, IO.raiseError(new TimeoutException("timeout!!!")))
      (offerer.start *> taker).replicateA_(1000).void
    }

[djspiewak]

Oooooooh associativity

[djspiewak]

Confirming that the test is just incorrect. Nuts.