Drop Scala 2.12 and sbt 1.3 (and 0.13.x leftovers)

[mkurz]

No description provided.

[mkurz]

@SethTisue as you are a Scala expert, is there something we should change here:

playframework/core/play/src/main/scala/play/api/mvc/Action.scala

Lines 99 to 101 in f18c239

	trait BodyParser[+A] extends (RequestHeader => Accumulator[ByteString, Either[Result, A]]) {
	// "with Any" because we need to prevent 2.12 SAM inference here
	self: BodyParser[A] with Any =>

?

[marcospereira]

Some minor comments, but it is LGTM, @mkurz!

[SethTisue]

@SethTisue as you are a Scala expert, is there something we should change here:

This was done by @wsargent in c9d2b33

Dale found that Will wrote a longer explanation of what's going on here, in this GitHub comment: #6691 (comment)

The SAM conversion rules are largely the same in 2.13 and 3 as they were in 2.12, but there are minor differences around the edges, e.g. in the interaction with overloading, but perhaps also in either areas.

So it's conceivable that this is no longer needed somehow, but it's also highly plausible it is still needed and appropriate, so I'd say just leave it unless you're really interested in digging into it.

[mkurz]

...so I'd say just leave it unless you're really interested in digging into it.

Not interested 😆

[xuwei-k]

as you are a Scala expert, is there something we should change here:

Here is minimized example.

class X1
class X2
class Request
class Result

trait BodyParser1[A] extends (X1 => A)

object ActionBuilder1 {
  def apply[A](parser: BodyParser1[A]): X2 = ???
  def apply[A](block: Request => Result): X2 = ???
}

trait BodyParser2[A] extends (X1 => A) {
  self: Any => // avoid SAM
}

object ActionBuilder2 {
  def apply[A](parser: BodyParser2[A]): X2 = ???
  def apply[A](block: Request => Result): X2 = ???
}

object Main {
  ActionBuilder1(a => ???) // "missing parameter type" error

  ActionBuilder2(a => ???) // no error
}

playframework/core/play/src/main/scala/play/api/mvc/Action.scala

Lines 284 to 305 in 619b319

	final def apply[A](bodyParser: BodyParser[A]): ActionBuilder[R, A] = new ActionBuilder[R, A] {
	override def parser = bodyParser
	protected override def executionContext = self.executionContext
	protected override def composeParser[T](bodyParser: BodyParser[T]): BodyParser[T] = self.composeParser(bodyParser)
	protected override def composeAction[T](action: Action[T]): Action[T] = self.composeAction(action)
	override def invokeBlock[T](request: Request[T], block: R[T] => Future[Result]) = self.invokeBlock(request, block)
	}
	/**
	* Constructs an `Action` with default content.
	*
	* For example:
	* {{{
	* val echo = Action { request =>
	* Ok("Got request [" + request + "]")
	* }
	* }}}
	*
	* @param block the action code
	* @return an action
	*/
	final def apply(block: R[B] => Result): Action[B] = async(block.andThen(Future.successful))

I think with Any is still needed Scala 2.13

[xuwei-k]

BTW with Any does not work with Scala 3.x 😢

-- [E051] Reference Error: A.scala:25:2 ----------------------------------------
25 |  ActionBuilder2(a => ???)
   |  ^^^^^^^^^^^^^^
   |Ambiguous overload. The overloaded alternatives of method apply in object ActionBuilder2 with types
   | [A](block: Request => Result): X2
   | [A](parser: BodyParser2[A]): X2
   |both match arguments (<?> => <?>)

[mkurz]

Thanks @xuwei-k!

BTW with Any does not work with Scala 3.x 😢

We can have a look at this later when actually adding Scala 3 support for Play.

[octonato]

Looks good. Thanks @mkurz

[mkurz]

Thanks Renato!