[play-json] JsResult `collect`, `filter`, `filterNot` no by-name parameters

Play Framework
1

Hi.

I am using Play JSON 2.6.10. Currently the 2-arity methods mentioned above do not use by-name parameters for the error case:

def collect[B](otherwise: JsonValidationError)(p: PartialFunction[A, B]): JsResult[B]

This comes to me a bit as a surprise, as the error case is always evaluated.

In our case, we wanted to use side-effects, ie. log a warning when validation failed:

val result = for {
  provider ← (v \ "provider").validate[String]
} yield provider match {
   case "whatever" => Some(Whatever)
}

result.collect {
  logger.warn("could not validate provider: " + v))
  JsonValidationError("...")
} {
  collect Some(x) => x
}

Now, the warrning is logged for every call of the validation function, regardless whether it failed or not.

Is this something that should / could be changed?

Thanks!