ScalaBuildTarget: split `jars` into `scalacJars` and `scaladocExtraJars`

In Scala 2 jars contains compiler jars which can also be used to generate scaladoc (because it’s built-in into scala-compiler.jar). In Scala 3 the set of jars required for ScalaDoc includes 42 jars. Only 13 of those jars are required to create a scala compiler instance.

Currently ScalaBuildTarget.jars returns all 42 jars for Scala 3. This leads to compiler classpath pollution.

see related: IntellIJ: sbt projects: Scala3 SDK compiler classpath contains redundant jar files Add ScalaInstance.loaderCompilerOnly

I already have a local fix for sbt projects (https://youtrack.jetbrains.com/issue/SCL-19086) via patching sbt-structure-extractor plugin

We could replace ScalaBuildTarget.jars field with scalacJars (13 jars) and scaladocExtraJars (29 jars). add methods getScalacJars, getScaladocExtraJars, getScaladocJars = getScaladocJars ++ getScaladocExtraJars

deprecate methods getJars, setJars getJars would by default return getScaladocJars setJars would set scalacJars, but probably would set scaladocExtraJars to an empty list

[olafurpg]

This is a good observation. How about adding scaladocJars and keeping jars unchanged? We should try to avoid breaking changes at all cost. It would have no effect in Scala 2. I assume most BSP clients will only use the compiler jars anyways.

[jastice]

BTW is there a list of known BSP clients or is it just IntelliJ and Metals?

It’s pretty much just those two right now, yes.

So that implies that BSP implementations need to fix their implementation not to include redundant classpath jars to ScalaBuildTarget.jars?

Yes