Upgrade to Scala 3

[Ragazoor]

Hello! 👋
I really want to use zio-actors for a toy project and thought this could become a good first open source contribution:)

This PR is first and foremost to get zio-actors to build on scala 3. I tried to (almost) only make changes that would make the project compile on Scala 3 and solve issue #308. Below is a summary of the changes I made:

• Upgraded most libraries to versions that are compatible and support scala 3
• Removed the dependency on scala-reflect (dropped in Scala 3)
• Migrated compiler flags for scala 3 (and added flags unique for scala 3)
• Migrated minor syntax things like imports (._ to .*) and wildcard types [_] to [?]
  • Undid this because +publishLocal stopped working, (zio-http also runs with import foo._)
• Higher kinded types seems a bit iffy, biggest issue was problems like these 1 and 2.
  • Solved by adding a wrapper to the PendingMessage[F[_],A] type (migration notes)
  • I removed the type parameter needed for akka messages.
    • I didn't see why messages used for AkkaTypedActorRefLocal needed a type parameter, it is not how akka does it, we don't use it and it was hard to make it work on scala 3...
    • Updated akka-interop docs a little with the change.
• Renamed some things to improve readability (imo). Some names in akka-interop tests, type parameters with the ! / ? methods to make it clearer what is the response vs request type
• Could not get the ActorSystem or the Context class to compile on all scala versions so I tried to break out common logic as best as I could to a base class which is shared, and the parts with type issues are scala 2/3 specific

Happy new year! 🎉

Edit: I'm trying to look at the zio-http project but I'm not familiar with this kind of sbt. I will see if I can get it to compile on all platforms (Made it!)

[CLAassistant]

All committers have signed the CLA.

[vigoo]

If I see it correctly the only version-specific difference is Actor[Any] vs Actor[?] here. Is Scala 2 not compiling with ? (or _?)?

[Ragazoor]

That's correct, I have made a few attempts on scala 2.13 but haven't been able to make it work... Get errors like:

private val initActorRefMap: Ref[Map[String, Actor[_]]], _$2 takes no type parameters, expected: 1
                                                   ^

I have also tried to make scala 3 compile with Actor[Any] but get errors like:

Type argument Any does not have the same kind as its bound [+_$1]

[Nojipiz]

Is this update supposed to be launch soon?

[liushihai]

When will this update be released?

[Ragazoor]

If you are waiting for it I think the best course of action is to go into the zio discord and ask if someone can release it for you since this library is unmaintained. I had to go there to get someone to review my code.