Release 2.12.2

[adriaanm]

we'll document the steps taken in releasing 2.12.2 here (taken from our currently internal release checklist)

[SethTisue]

there is a checklist now at #332 that I can copy here when the time comes.

some additional notes:

• 2.11.9 2.11.10 is a prerequisite. (in general, but also specifically: case class apply/unapply, SCP-009 direct-dependency work)
• draft release notes ahead of time, not at the end of the process
• triage open JIRA tickets listed as 2.12.2
• triage open scala-dev tickets listed as 2.12.2
• update LICENSE in root dir
• check in with @dwijnand about trailing commas stuff (trailing commas followup #299); we want to make sure that all rolls out smoothly
• before releasing, tell the community which nightly we intend to rebrand as 2.12.2, and invite them to test it

[SethTisue]

status update: 2.11.9 is on Maven Central but not announced (while Adriaan looks into a possible regression). we're still expecting/hoping to release 2.12.2 next week after merging a few additional PRs. the shape of the release can be seen from the 2.12.2 milestone, especially the PRs with the release-notes tag

[xuwei-k]

There is a same issue as Scala 2.11.9 (broken forward binary compatibility)

• xuwei-k/Scala-2.11.9-FilteredTraversableInternal@ad12603
• scala/scala@eb5c513

[adriaanm]

Thank you @xuwei-k. Glad you caught this before 2.12.2! I will revert the incompatible change.

[SethTisue]

most 2.12.2 JIRA tickets have now been assigned to "Backlog" or 2.12.3. four open tickets left at https://issues.scala-lang.org/issues/?jql=project%20%3D%20SI%20AND%20status%20%3D%20Open%20AND%20fixVersion%20%3D%20%22Scala%202.12.2%22%20ORDER%20BY%20status%20ASC , the relevant PRs are scala/scala#5762 and scala/scala#5402

[lrytz]

we should probably also merge 2.11.x to 2.12.x once 2.11.10 is tagged

[SethTisue]

@adriaanm I'm hoping you could do the 2.11->2.12 merge, since you're already spun up on what the changes are

[adriaanm]

Merge PR: scala/scala#5837

[adriaanm]

• I'll double check the bytecode. (for the record, Optimizations in immutable.Map.{get, contains} scala#5673, SD-256 enable colored output by default on unix scala#5663, Improve Queue.++ when building another Queue scala#5579 added bytecode-public methods)
• could someone else (@szeiger?) check the PRs I listed above and make sure we're still cool shipping them, knowing what we learned from 2.11.9?

Here's the full bytecode diff of the library from 2.12.1 to 2.12.2: https://gist.github.com/adriaanm/dccef51d7ef9aa2bb1c0688945d4c8cd

[SethTisue]

scala/scala#5402 is merged. I pushed some community build tweaks and started a trial release-main job. current release candidate is scala/scala@15e2759

[lrytz]

pcplod failed in a strange way (https://scala-ci.typesafe.com/job/scala-2.12.x-integrate-community-build/1414/consoleFull)

[pcplod:error] scala.MatchError: fef15bff+20170411-0503-SNAPSHOT (of class java.lang.String)
[pcplod:error] 	at com.typesafe.dbuild.project.build.LocalBuildRunner$.prepareDepsArtifacts(LocalBuildRunner.scala:110)

maybe the switch to a new branch in scala/community-build@7032ae8 caused the version number to change?