2.12.7 release 🚋

It’s time for another 2.12 minor release!

Please review:

We intend to close the PR queue in the next few days, and stage the release by the end of the week. First, a few more PRs (mostly compiler performance) remain to be reviewed (your help always appreciated!), and we still need to backport the work @retronym did in 2.13.x on fixing some issues with reproducible compilation.

If you feel we missed any critical, release-blocking issues for 2.12.7, please let us know!

We’re very excited that Spark 2.4 is now also building on 2.12 (thanks for #7156, @sadhen!). Spark 2.4 should be out soon, with beta support for Scala 2.12.

Barring unforeseen issues, we plan to wait with 2.12.8 until after the 2.13.0 final. As a reminder, 2.12.x is in maintenance mode, and 2.13.x is feature frozen, ramping down. Our focus is on polish for the 2.13.0 final release: performance, stability, documentation, and improved cross-building between 2.12 & 2.13. I will post separately about the themes for 2.14 soon!


I really like the train icon for this. Clearly marks the thread.
Recommending to adopt for all future release threads. @SethTisue


There is, but it’s steam powered (:steam_locomotive: ). Not sure about the signal that would send about the release process.

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Hi Adrian,

 you may be looking for 🚄 (U+1F684), 🚅 (U+1F685) or 🚆 (U+1F686)

Quite accurate, if I can relate to any release process I know of :slight_smile:

I think we’ve gathered enough steam for take off. Still waiting for community build results on Java 11 today, and then I’ll pull the levers. Follow progress in more detail on the usual release ticket https://github.com/scala/scala-dev/issues/558

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we decided to include two additional PRs in 2.12.7:

these are merged, and the new release candidate is 2.12.7-bin-727964b:

resolvers += "scala-integration" at
scalaVersion := "2.12.7-bin-727964b"

community build validation is still in progress. note that our Jenkins now runs the community build on JDK 11 (details) as well as JDK 8

The 2.12.7 release is now staged (available by adding a resolver for “https://oss.sonatype.org/content/repositories/staging/”).


From now on, we shall call it the “release tram”


How is it going guys? Is there any date scheduled?


The release is staged. We’re assessing the severity of two regressions discovered by the community build before we promote the release. See the ticket for details (https://github.com/scala/scala-dev/issues/558)

I identified the regressions and proposed a fix: https://github.com/scala/scala/pull/7261

We will carefully vet, re-run the community build, and then hopefully on to the real 2.12.7!

at https://github.com/scala/scala-dev/issues/558#issuecomment-424648641, Adriaan writes:

Ok, the scope of the reversion has been reduced thanks to @milessabin, and we also added a fix for a hashcode regression (scala/bug#11171).

The new RC sha is d96b8eb.

so that’s:

resolvers += "scala-integration" at
scalaVersion := "2.12.7-bin-d96b8eb"

a new community build run is in progress.

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@SethTisue great work on the community build. It clearly pays off!


Scalameta SemanticDB and paradise are ready to publish for 2.12.7 :muscle: Big thanks to Jason for upgrading SemanticDB!

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2.12.7 is making its way over to maven central!


Hi @adriaanm, any chance this ‘soon’ will come sooner :wink: ?

We’re preparing a blog about the 2.14 roadmap between 2.13.0 final and scala days, where Lukas will talk about this topic as well. At a high level, it will focus on Scala 2&3 compatibility through a combination of TASTY, ABI compatibility (aligning the backends), shared standard library and selective backporting of Scala 3 features (still tbd, but likely trait params, type lambdas, opaque types)