Open
Description
Compiler version
3.2.0
Minimized code
import scala.concurrent.{Await, Future}
import scala.concurrent.duration._
object MapTest extends App {
import concurrent.ExecutionContext.Implicits.global
val test = "123"
val dataF = Future { List("111", "222", "333", test) }
Await.ready(dataF, 1.second)
}Output
Exception in thread "main" java.lang.ExceptionInInitializerError
at MapTest.main(MapTest.scala)
Caused by: java.util.concurrent.TimeoutException: Future timed out after [1 second]
at scala.concurrent.impl.Promise$DefaultPromise.tryAwait0(Promise.scala:248)
at scala.concurrent.impl.Promise$DefaultPromise.ready(Promise.scala:255)
at scala.concurrent.impl.Promise$DefaultPromise.ready(Promise.scala:104)
at scala.concurrent.Await$.$anonfun$ready$1(package.scala:174)
at scala.concurrent.BlockContext$DefaultBlockContext$.blockOn(BlockContext.scala:62)
at scala.concurrent.Await$.ready(package.scala:124)
at MapTest$.<clinit>(MapTest.scala:13)
... 1 more
java.lang.NoClassDefFoundError: Could not initialize class MapTest$
Expectation
I'm aware of the intricacies of DelayedInit and App. However, since this works in Scala 2.13, I would expect this to also work in Scala 3 because the doc hasn't change: doc dotty, doc 2.13.3.
Moreover, looking at this statement:
It should be noted that this trait is implemented using the DelayedInit functionality, which means that fields of the object will not have been initialized before the main method has been executed.
it's not clear why wrapping code into a Future makes any difference. Isn't access to test on line 3 happening before the method has been executed? 🤔
object PrintTest extends App {
val test = "123"
println(test)
}