java.lang.LinkageError: loader constraint violation :: class loader com.intellij.ide.plugins.cl.PluginClassLoader error

[teeckoo]

we are using sbt-idea plugin for development of a intellij plugin.
our plugin have functionality that depends on org.intellij.scala:2025.1.20

we are getting LinkageError: loader constraint violation inside action.

a very simplified project can be found here to reproduce problem.

[teeckoo]

looks like if we comment below from ij-plugin/build.sbt, then LinkageError is gone.

libraryDependencies ++= Seq(
  "org.typelevel" %% "cats-effect" % "3.4.4",
  "org.typelevel" %% "mouse" % "1.2.3",
  "com.github.pathikrit" %% "better-files" % "3.9.2"
)

but how to get rid of LinkageError while using above dependencies, as plugin depends on these libraries

[teeckoo]

not sure but looks like, this fix is merged for similar issue

kindly suggest

[teeckoo]

packageLibraryMappings := Seq.empty
also didn't worked as suggested here

[vasilmkd]

Hi 👋🏻 . Thanks for opening this issue. I will use your reproducer project to see how to proceed. Thank you for that!

[vasilmkd]

Hi again. So, the problem seems to be that the scala-library ends up packaged with the plugin, and this causes some class loading conflict in IDEA.
At the moment, I cannot understand why the setting ThisBuild / bundleScalaLibrary := false doesn't seem to do anything.

The following worked for me:

    packageLibraryMappings ++= Seq(
      "org.scala-lang"  % "scala-.*" % ".*"        -> None,
      "org.scala-lang.modules" % "scala-.*" % ".*" -> None
    )

I added this to the .settings() block of the root project lazy val scalaIntellij = project.in(file(".")).

This excludes the scala-library from the packaged plugin and seems to resolve the problem.

Let me know if this works for you as well.

[teeckoo]

Yes, the above suggestion works well for now 👍

Should I open a new issue for setting bundleScalaLibrary := false,
or should this be addressed as part of the current issue?

[vasilmkd]

Let's keep this one open. Thanks.