Scala-3.5.0 runner requires JDK-17+ on BSD

[catap]

Compiler version

Scala compiler version 3.5.0 -- Copyright 2002-2024, LAMP/EPFL

Minimized example

$ env JAVA_HOME=/usr/local/jdk-1.8.0 scala

Output

scala $ env JAVA_HOME=/usr/local/jdk-1.8.0 scala 
Error: java.lang.Exception: Unrecognized OS: openbsd
For more details, please see '/usr/ports/lang/scala/.scala-build/stacktraces/1725217762-8871160887746307735.log'
scala $ cat /usr/ports/lang/scala/.scala-build/stacktraces/1725217762-8871160887746307735.log
java.lang.Exception: Unrecognized OS: openbsd
  coursier.jvm.JvmIndex$.defaultOs(JvmIndex.scala:173)
  scala.build.internal.OsLibc$.jvmIndexOs$lzyINIT1(OsLibc.scala:59)
  scala.build.internal.OsLibc$.jvmIndexOs(OsLibc.scala:58)
  scala.cli.javaLauncher.JavaLauncherCli$.runAndExit(JavaLauncherCli.scala:22)
  scala.cli.ScalaCli$.main0(ScalaCli.scala:251)
  scala.cli.ScalaCli$.main(ScalaCli.scala:117)
  scala.cli.ScalaCli.main(ScalaCli.scala)
scala $

Expectation

Should work.

The root cause of this issue is scalacenter/bloop#2355 which introduced this lines https://github.com/scalacenter/bloop/blob/v2.0.0/cli/src/main/scala/bloop/cli/util/OsLibc.scala#L64-L70 whiich uses on JDK before 17 https://github.com/coursier/coursier/blob/v2.1.10/modules/jvm/src/main/scala/coursier/jvm/JvmIndex.scala#L154-L160 where an exception for non Windows, Linux or Darwin.

[Gedochao]

@catap I believe this will be a wontfix.

In order to make Scala CLI work on OpenBSD with Bloop (the build server), you'd need to install Java 17 manually.
Alternatively, you could work around this by skipping the build server with --server=false.

env JAVA_HOME=/usr/local/jdk-1.8.0 scala --server=false

More details on this in https://scala-cli.virtuslab.org/install#:~:text=BSD%20(-,experimental,-)
(BSD support for Scala CLI is not considered stable).

What we could potentially do ecosystem wide to improve this:

• include JVM indexes for BSD in https://github.com/coursier/jvm-index
  • it's also possible to build custom indexes for coursier to use, see https://github.com/coursier/jvm-index?tab=readme-ov-file#generating-the-index-locally
  • I suspect this will be tricky
• for now default to --server=false if JVM 17+ is not found for BSD only? (I have mixed feelings about this, would rather not do that, might warrant a discussion in https://github.com/VirtusLab/scala-cli/discussions

cc @hamzaremmal, in case I missed something

[ritschwumm]

@Gedochao maybe it's possible to at least have a more helpful error message?

[catap]

@ritschwumm and document it somewhere!