Make coverage support incremental compilation

[lolgab]

Port of scoverage/scalac-scoverage-plugin#742 for Scala 3.

[tgodzik]

Thanks for working on this. Let me know when this is ready! Seems like github actions are having a tough day though, so we'll need to rerun some jobs.

[lolgab]

Thanks for working on this. Let me know when this is ready! Seems like github actions are having a tough day though, so we'll need to rerun some jobs.

I want to port the tests as well, but I'm having trouble running the tests.

I get:

sbt:scala3-nonbootstrapped> last scala3-library-nonbootstrapped / scalaInstance
[error] java.lang.RuntimeException: Missing Scala tool configuration from the 'update' report.  Explicitly define scalaInstance or scalaHome or include Scala dependencies in the 'scala-tool' configuration.
[error]         at scala.sys.package$.error(package.scala:30)
[error]         at sbt.Defaults$.$anonfun$scalaInstanceFromUpdate$10(Defaults.scala:1214)
[error]         at scala.Option.getOrElse(Option.scala:189)
[error]         at sbt.Defaults$.$anonfun$scalaInstanceFromUpdate$1(Defaults.scala:1214)
[error]         at scala.Function1.$anonfun$compose$1(Function1.scala:49)
[error]         at
......
[error] (scala3-library-nonbootstrapped / scalaInstance) Missing Scala tool configuration from the 'update' report.  Explicitly define scalaInstance or scalaHome or include Scala dependencies in the 'scala-tool' configuration.

[tgodzik]

I think for coverage it should be sbt scala3-compiler-nonbootstrapped/testOnly dotty.tools.dotc.coverage.CoverageTests does it work for you?

[lolgab]

@tgodzik Thank you. I needed to cleanup my workspace directory since I had last compiled Scala3 a long time ago and something was broken in the target directories. I can run tests now