The .start method callback is sometimes not called

[kafejo]

The .start method callback is sometimes not called

[Widcket]

Hi @kafejo, thanks for raising this.

I cannot consistently reproduce it but I call this on every app launch and 1 out of 5 launches don't receive the start callback. The only thing I could observe is that it happens usually after launching this method after 5-10 minutes.

Sorry, I'm afraid I don't follow. You mention that you're calling this method on every app launch, but also that you're only observing this after 5-10 minutes. Could you please expand on this? Are you observing this on app launch, or after?

[kafejo]

Hi @Widcket, apologies for not being more clearer in my description. What I meant is that it seemed to happen only when I launched the app in a space of 5-10 minutes. It does happen on a launch. Upon further investigation it seems like the underlying data task completion handler is not being called under certain conditions.

public func start(_ callback: @escaping Callback) {
      let handler = self.handle
      let request = self.request
      let logger = self.logger

      logger?.trace(request: request, session: self.session)


      let task = session.dataTask(with: request, completionHandler: { data, response, error in
          if error == nil, let response = response {
              logger?.trace(response: response, data: data)
          }
          handler(Response(data: data, response: response as? HTTPURLResponse, error: error), callback)
      })
      task.resume()
}

I placed breakpoints before and in that completionHandler. The breakpoint before the dataTask method is triggered always but the one inside is not.

[Widcket]

Thanks for the information. As you can see in the snippet shared above, we're always calling the handler; we do not return early at all. Are you sure you're not calling this from inside a Task that is getting cancelled, or something similar?

[kafejo]

Yeah I can see that. It's not that the you never call the handler. It's more that the completionHandler of the data task seems not to be called in certain conditions. I noticed you are using a shared URLSession so I'm wondering can that have anything to do with it?

[Widcket]

Yes, the session defaults to URLSession.shared. I'll go ahead and close this issue for now, as it's not an SDK bug. Please feel free to ping if you'd prefer to reopen.