Xcode: Error Domain=DVTPlaygroundCommunicationErrorDomain Code=1

ios, macos, swift, xcode

Solution

Set `needsIndefiniteExecution` to `true` can omit this warning. The warning happens once playground execution ends earlier than thread processing.

import PlaygroundSupport
PlaygroundPage.current.needsIndefiniteExecution = true

Problem

I'm attempting to test the cancellation of a `DispatchWork` item within a Swift Playground, although during the first few milliseconds of execution there's an error, which I'm not sure what it's actually indicating, nor can I tell if the error is causing the cancellation rather than the `cancel()` method... ``` func testDispatchWorkItems() { let queue = DispatchQueue.global(qos: .userInitiated) var item: DispatchWorkItem? // create work item item = DispatchWorkItem { for i in 0 ... 100000 { if item!.isCancelled { break } print(i) } } // start it queue.async(execute: item!) // after three seconds, stop it queue.asyncAfter(deadline: .now() + 3) { item?.cancel() } } testDispatchWorkItems() ``` ``` 2016-10-26 11:14:33.898 com.apple.dt.Xcode.PlaygroundStub-macosx[30685:18567692] Error encountered communicating with Xcode: Error Domain=DVTPlaygroundCommunicationErrorDomain Code=1 "Cannot send data because stream is closed." UserInfo={NSLocalizedDescription=Cannot send data because stream is closed.} ``` Has someone got an idea what that error is indicating?

Original source