Scala waiting for sequence of futures

Question

I was hoping code like follows would wait for both futures, but it does not.

object Fiddle {
  val f1 = Future {
    throw new Throwable(\"baaa\") // emulat         


        

Answer 1

A Future produced by Future.sequence completes when either:

• all the futures have completed successfully, or
• one of the futures has failed

The second point is what's happening in your case, and it makes sense to complete as soon as one of the wrapped Future has failed, because the wrapping Future can only hold a single Throwable in the failure case. There's no point in waiting for the other futures because the result will be the same failure.