[schrodinger]

I think you could do which I'd argue is more idiomatic (

    for {
      if _, ok := <- doneCh; ok {
        break
      }
      select {
      case thing := <-thingCh:
        // ... long-running operation
      case <-time.After(5*time.Second):
        return fmt.Errorf("timeout")
      }
    }

Which goes along w/ https://github.com/golang/go/wiki/CodeReviewComments#indent-... of "Indent error flow".

edit: nvm, your break would be blocked until one of the other channels produced a value. you'd need to check for the doneCh redundantly again in the select.