Scala 2.12.18 release planning

SethTisue · February 17, 2023, 2:50am

This thread is for updates and discussions about the upcoming Scala 2.12.18 release.

The main motivation for the release would be to add JDK 20 support. (As usual, a new JDK version requires an ASM upgrade in order for the optimizer work.) The necessary changes, by Philippus Baalman, have already been merged. Oracle’s target release date for JDK 20 is March 21, 2023.

Timing-wise, we intend to do 2.12.18 and 2.13.11 at the same time; see the 2.13.11 release planning thread.

Our team at Lightbend has also been making some changes to help users migrate from 2.12 to 2.13, typically under the -Xsource:2.13 flag.

The 2.12.18 milestone on GitHub has lists of open and merged PRs for the release. You may wish to filter by the “release-notes” label to see only the most significant changes.

Feel free to use this thread to ask questions and share concerns about the timing and contents of the release.

SethTisue · March 9, 2023, 7:02pm

We’ve just finished QAing the current 2.12 nightly on JDK 20 and all is well. Our test suite is green and will run nightly on JDK 20 from now on, and the same is true of the Scala 2.12 community build.

SethTisue · March 27, 2023, 4:19pm

An update on timing: 3.3.0 is a bit delayed (not before April 17, is my understanding, since we don’t have RC4 yet), so that pushes 2.12.18 until at least April 20.

SethTisue · May 3, 2023, 2:07am

3.3.0-RC5 is now out. With a little luck, 3.3.0 will follow before too much longer.

2.12.18 seems to be in good shape. There are no remaining open tickets or pull requests.

If you would like to test a release candidate, it’s 2.12.18-bin-d56572e.

You can scala-cli -S 2.12.nightly, or see these instructions.

SethTisue · May 3, 2023, 2:58am

Scala 2.12.18 draft release notes:

github.com

scala/scala-dev/blob/scala-2.12.18/releases/2.12.18.md

# Scala 2.12.18

This release improves **compatibility**:

* Support JDK 20 with ASM 9.5 upgrade, by @Philippus ([#10185](https://github.com/scala/scala/pull/10185), [#10362](https://github.com/scala/scala/pull/10362))

It also aids **migration** to Scala 2.13 and Scala 3:

* Under `-Xsource:2.13`, warn when inherited takes precedence over outer definitions ([#10297](https://github.com/scala/scala/pull/10297), [#10321](https://github.com/scala/scala/pull/10321))
* Under `-Xsource:2.13`, flag eta-expanding methods without parameter lists ([#10283](https://github.com/scala/scala/pull/10283))
* Under `-Xsource:2.13`, don't GLB binders of type patterns, use the type directly ([#10298](https://github.com/scala/scala/pull/10298))

and improves **linting**:

* Lint for integral divisions that are widened to a float ([#10313](https://github.com/scala/scala/pull/10313))

and enables improved **tooling**:

* Preserve tree attachment in the typer's `Block`/`Apply` inversion transform ([#10176](https://github.com/scala/scala/pull/10176))

This file has been truncated. show original

If you have any suggested improvements to the notes themselves, you can comment on this pull request.

tgodzik · May 5, 2023, 2:52pm

Both Scalameta and Metals work with the newest release candidate for 2.12.18

A WIP PR for Scalameta is here chore: Add support for Scala 2.12.18 by tgodzik · Pull Request #3120 · scalameta/scalameta · GitHub

SethTisue · May 22, 2023, 10:28pm

We have a new release candidate: 2.12.18-bin-ceaf7e6. The only change since the last candidate is a classfile parsing fix that makes the compiler work on the current JDK 21 early access build.

SethTisue · May 24, 2023, 9:03pm

Just to be maximally clear about timing: our release candidate, 2.12.18-bin-ceaf7e6, was announced here on Monday, May 22. Unless someone finds some serious late breaking problem in testing, we’ll build 2.12.18 no sooner than Tuesday, May 30.

To test the nightly, you can scala-cli -S 2.12.nightly, or see these instructions.

Note that Scala 3.3.0 is now on Maven Central. (As usual, the publication of those JARs is just an early step in the overall release process.)

SethTisue · June 1, 2023, 3:13am

2.12.18 JARs are now on Maven Central.

Tooling and compiler plugin maintainer powers, activate! Please publish support.

We won’t announce before Wednesday, June 7, 2023. (This is a little longer wait than usual, because we are coordinating with 2.13.11.)

sjrd · June 1, 2023, 5:01am

The compiler plugins of Scala.js 1.13.1 are on their way to Maven Central for Scala 2.12.18.

I will release some earlier versions later today.

Edit: all versions since v1.7.1 are now available for Scala 2.12.18.

WojciechMazur · June 1, 2023, 9:42am

Scala Native compiler plugins for 2.12.18 are on their way to Maven Central (last 3 releases 0.4.10-0.4.12)

tgodzik · June 1, 2023, 1:36pm

Scala 2.12.18 is now supported in Scalameta 4.7.7-4.7.8 and Metals 0.11.12. Nightlies will be updated soon.

eed3si9n · June 2, 2023, 3:29pm

Hi, is this available on Maven Central?
https://repo1.maven.org/maven2/org/scalameta/semanticdb-scalac_2.12.18/ returns 404 today (2023-06-02).

SethTisue · June 2, 2023, 5:50pm

Eugene: I’ve noticed recently that repo1.maven.org may 404 on a directory listing even when the directory exists and its content exists. So for example https://repo1.maven.org/maven2/org/scala-lang/scala-library/2.12.18/ is still 404 even days after I published it, but the actual files such as https://repo1.maven.org/maven2/org/scala-lang/scala-library/2.12.18/scala-library-2.12.18.jar are present and resolvable by sbt, scala-cli, et al.

It looks to me like this is also happening with the directory you mention.

(I assume, or at least hope, that the directory listings will eventually catch up with reality…?)

eed3si9n · June 2, 2023, 8:18pm

That’s gnarly, and you’re right – Central Repository: org/scalameta/semanticdb-scalac_2.12.18/4.7.8 is there!

bjaglin · June 4, 2023, 9:45pm

scalafix & sbt-scalafix 0.11.0 are on Maven central, built with and supporting 2.12.18

thanh · June 7, 2023, 2:41pm

I still get 404 today (07/06/2023) when using sbt 1.9.0 with semantic db? I guess this is an issue now, because it’s been a few days since the artifact was published.

SethTisue · June 7, 2023, 3:38pm

Scala 2.12.18 is announced. Thanks all!

@thanh can you share an exact reproduction so we can see it happen on our own computers…?

thanh · June 7, 2023, 3:59pm

yes of course. I set Global / semanticdbEnabled := true in ~/.sbt/1.0/global.sbt.
and it fails for any projects that use sbt 1.9.0.
Here is the logs:

[lila] $ reload
[info] welcome to sbt 1.9.0 (Eclipse Adoptium Java 17.0.7)
[info] loading settings for project lila-build-build-build from metals.sbt ...
[info] loading project definition from /Users/tle/git/lichess/lila/project/project/project
[info] Updating
[info] Resolved  dependencies
[warn]
[warn]  Note: Unresolved dependencies path:
[error] stack trace is suppressed; run last update for the full output
[error] (update) sbt.librarymanagement.ResolveException: Error downloading org.scalameta:semanticdb-scalac_2.12.18:4.5.13
[error]   Not found
[error]   Not found
[error]   not found: https://repo1.maven.org/maven2/org/scalameta/semanticdb-scalac_2.12.18/4.5.13/semanticdb-scalac_2.12.18-4.5.13.pom
[error]   not found: /Users/tle/.ivy2/local/org.scalameta/semanticdb-scalac_2.12.18/4.5.13/ivys/ivy.xml
[error]   not found: https://repo.scala-sbt.org/scalasbt/sbt-plugin-releases/org.scalameta/semanticdb-scalac_2.12.18/4.5.13/ivys/ivy.xml
[error]   not found: https://repo.typesafe.com/typesafe/ivy-releases/org.scalameta/semanticdb-scalac_2.12.18/4.5.13/ivys/ivy.xml
[warn] Project loading failed: (r)etry, (q)uit, (l)ast, or (i)gnore? (default: r)

tgodzik · June 7, 2023, 4:41pm

Could you also set the semanticdb version to a newest one? We haven’t released semanticdb for all the older versions.

semanticdbVersion := "4.7.8"