think i found it. -Dkotlin.compiler.execution.strategy="in-process"

jw: Not sure it should be used. Kotlin compiler in-process can conflict with Kotlin compiler used by gradle to compile GSK build scripts.

I'm fine with it running out of process, but I want it to exit when the task is done.

They are listed here https://github.com/JetBrains/kotlin/blob/master/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/compilerRunner/GradleKotlinCompilerRunner.kt#L45

BTW @ilya.gorbunov is not quite right. Running compiler in-process is a viable option. It will be launched in an isolated classloader, so it will not clash with kotlin runtime bundled in Gradle (for GSK). There is a few caveats though: 1.

in-process

&

out-of-process

do not support IC at the moment (which is not a problem for CI). 2. in theory we could try to cache

in-process

isolated classloader for a build, so the compiler classes would be optimized by JIT between compiler invokations. However previously caching classloader lead to memory leak, so for now we creating a new classloader for each invocation of the compiler (I'm going to look into this later). 3. Running compiler in-process can lead to a JVM crash https://youtrack.jetbrains.com/issue/KT-17031 (there is a workaround in the issue). // cc @jw