Apollo disconnectStream crash

[m1entus]

Bug report

Hey, we are getting crash when entering background or returning from background (not fully sure because it is hard to reproduce it locally, but see Testflight crash logs and getting this info from our testers). I think it might be a problem that sockets are not running when app is in background and you can have race condition? when reconnecting.

Versions

Please fill in the versions you're currently using:

• apollo-ios SDK version: 0.51.0
• Xcode version: 13.3.1
• Swift version: 5.6
• Package manager: Pods

Steps to reproduce

Hard to reproduce but is happening when app is backgrounded.

Further details

Seems you are using Starscream for Websockets and this was similar issue: daltoniam/Starscream#500

Feel that you should not reconnect from DispatchQueue.main.asyncAfter but instead use processing queue inside WebSocketTransport processingQueue.asyncAfter.

In addition to that feels that you have guys retain cycle inside WebsocketTransport:243 and some places too:

processingQueue.async {
      if let str = str {
        self.write(str)
      }

      self.queue.removeAll()
      self.subscriptions.removeAll()
    }

in that case self is holding strong reference to processingQueue and processingQueue strong to self

[AnthonyMDev]

Thanks so much for this report! We're going to be rewriting a lot of this section in the coming months. But we don't want crashing happening, even in the background. We'll look into this.