Always set JVM 8 target in Scala compiler

[rshkv]

Before this PR

Projects with gradle-baseline cannot compile Scala code if they set Java targetCompatibility to 11. The error is:

> Task :optimizer-rules:compileScala
'jvm-11' is not a valid choice for '-target'
bad option: '-target:jvm-11'

BaselineScalaStyle sets scalac -target to match that of javac. However scalac 2.12 only accepts target values up-to jvm-8 (see here). Scala version 2.13 supports higher targets, but 2.12 was released July this year and we still need to support it.

After this PR

Edit: No longer set target version for Scala compiler to match that of Java compiler.

==COMMIT_MSG==
Always set target version for Scala compiler to JVM 8.
==COMMIT_MSG==

Possible downsides?

If using scalac 2.13 (which permits jvm-9+), this change can result in a lower target version. I don't think that's dangerous but might be overlooking something.

jvm-7 and lower are disallowed by 2.12 - they wouldn't have been valid targets before. The last 2.11 version was released in 2016.

[changelog-app]

Generate changelog in changelog/@unreleased

Type

• Feature
• Improvement
• Fix
• Break
• Deprecation
• Manual task
• Migration

Description

No longer set target version for Scala compiler to match that of Java compiler.

Check the box to generate changelog(s)

• Generate changelog entry

[robert3005]

Scala 2.11 still requires it so either you have to drop it or just set it to 1.8

[rshkv]

True, it defaults to Java 6 in 2.11.12.

[rshkv]

I went with always setting the target to 8 as I don't find a straight-forward way to get the Scala version and offer a target based on that.

Personally, I'd still prefer to not have this here. I don't think we need to support 2.11. And if this happens to fail anyone, they can configure the right target themselves.

[robert3005]

I think setting it to target 1.8 is correct for now and we can remove it once we are sure we don't need scala 2.11 👍

[rshkv]

@CRogers, the trial-publish job is failing because javadoc is OOMing. I see the same on #1517.

[rshkv]

Also would appreciate a release. This is blocking source compatibility bumps 🙏

[svc-autorelease]

Failed to load project - please reach out to #dev-foundry-infra or check Aries to debug

[iamdanfox]

I think the changelog is malformed. changelog/@unreleased/pr-1524.yml should be changelog/@unreleased/pr-1524.v2.yml

[rshkv]

Contributors can't edit the changelog-app message.

[rshkv]

Will file PR.

[iamdanfox]

@rshkv you shouldn't have to fork if you're part of the palantir org. then you can edit the msg.

[rshkv]

I'm part of the org but can't push to this repo.

[robert3005]

#1525