3.4.0-RC2 Release procedure

[Kordyjan]

• Publish 3.4.0-RC2 artifacts to Maven via CI
  • On release-3.4.0 branch:
    • In changelogs add file with a changelog
    • In Build.scala: Set baseVersion to 3.4.0-RC2
    • In Build.scala: Set previousDottyVersion to 3.4.0-RC1
    • Tag the branch as 3.4.0-RC2
    • Build
• Wait for confirmation from tooling:
  • Metals (@tgodzik)
  • Scala CLI (@Gedochao)
  • Scala Native (@WojciechMazur)
  • Scastie (@rochala)
  • Scala DAP (@adpi2)
• Announce the releases
  • Make GitHub releases public
  • Update the 3.4.0 tracking thread

[nicolasstucki]

It seems we are releasing 3.4.0-RC2 with the experimental tag 1 https://github.com/lampepfl/dotty/blob/6dfb1b5eee1fc46fb9bdc1efd49ce359c09778bc/tasty/src/dotty/tools/tasty/TastyFormat.scala#L337

This does not seem to align with #19321 (comment). This seems to indicate we need experimental tag 2 for this release. @bishabosha did I interpret this correctly?

[Kordyjan]

If I'm not mistaken, there are no tasty format changes between RC1 and RC2, so there is no need to bump the experimental version.

[nicolasstucki]

The concern is that 3.4.0-RC1 had the wrong TASTy experimental version. And this one should have the same one. This is not critical, but it would imply that we will only be able to use 3.4.0 as a reference compiler and not 3.4.0-RC2.

[Kordyjan]

Yes, that's true, but I cannot see why 28.4-2 instead of 28.4-1 would make any difference, as the tasty version on nightly should be 28.5-1, which is incompatible with both of them.

[nicolasstucki]

We could have an extra rule in the version checks to allow -2 in this situation. Not sure what was the original plan with that version.

[Kordyjan]

Ok, I get what you mean. -2 in RCs of minors was something that was dropped sometime between September 2021 and March 2022. I don't remember why. As far as I remember, RCs for 3.1.0 were the last time something had a tasty version ending with -2.

[Kordyjan]

It may have been somehow related to the planned and later scrapped --scala-output-version, which was being developed around that time. I'm ok with bringing back -2 versions before 3.5.0.

[bishabosha]

the -2 would only be significant if we want to break compatibility between 3.3.x nightlies and 3.4.0-RC2, which is a noble goal but maybe not critical, the important thing is staying behind 28.4-0

[Kordyjan]

Artifacts for 3.4.0-RC2 are on maven central.

[tgodzik]

Works with Metals 🎉

[nicolasstucki]

An issue was found with the definitions of scala.language.`3.5` in #19503.

[Kordyjan]

An issue was found with the definitions of scala.language.`3.5` in #19503.

I must admit that I thought that scala.language.`3.5` should only be added in 3.5.0, and before that, things that will no longer work in 3.5 are marked as not working in scala.language.future.

[nicolasstucki]

I must admit that I thought that scala.language.3.5 should only be added in 3.5.0, ...

That might be the case. The most inportant part is to be consitent with 3.4.X patch releases (or nightlies).