Compiling from IntelliJ can cause UnsupportedClassVersionError using the preprocessor and using pre-JDK 17

[rsmckinney]

Compiling from IntelliJ can cause UnsupportedClassVersionError using the preprocessor and using pre-JDK 17.

The problem appears to be that IntelliJ sets JPS thread pool thread context class loader, which is the thread the compiler executes in. This loader is full of IntelliJ jars including plugin jars, all compiled with JDK 17. None of these jars should be visible to the ServiceLoader when used from the compiler, including from compiler plugins like manifold, annotation processors, etc. If a call is made to ServiceLoader#hasNext() in this situation and the compiler is older than JDK 17, it will blow up with UnsupportedClassVersionError. But really, none of these service impls should be loaded anyway since they are specific to IntelliJ and not the compiling project.

[rsmckinney]

Fixed with release 2022.1.38