Map the Exception of a failed Future

There is also:

f recover { case cause => throw new Exception("Something went wrong", cause) }

Since Scala 2.12 you can do:

f transform {
  case s @ Success(_) => s
  case Failure(cause) => Failure(new Exception("Something went wrong", cause))
}

or

f transform { _.transform(Success(_), cause => Failure(new Exception("Something went wrong", cause)))}