Crude solution to nil panic

nil_panic.go

func CaculateSomething(i int) (result int, err error) {
  // Does a bunch of math to calculate a value, or
  // returns an error when it can't.
  done := false
  defer func() {
    if !done {
      err = fmt.Errorf("panic: %+v", recover())
    }
  }()
  // ... the magic ...
  done = true
  return result, err
}