in Graal 20.x, getMetaObject returns null when called on a polyglot Value representing an ES module

[ispringer]

In Graal 19.3, getMetaObject returned a meta object, and we could check if a Value was a module using value.getMetaObject().toString().equals("Module"). In Graal 20.x, getMetaObject returns null, so have to check if a Value is a module using value.toString().equals("[Module]").

This change broke our code in several places. Was the change in behavior intentional?

Here is a failing Groovy test that demonstrates the issue:

@Test
void "Value#getMetaObject returns a non null value for an ES module"() {
    def vfs = new PolyglotInMemoryOnlyFileSystem()

    context = Context.newBuilder("js")
            .allowHostAccess(true)
            .option("js.ecmascript-version", "11") // ES2020 is required for import() call support
            .allowIO(true)
            .fileSystem(vfs)
            .build()

    addModule(vfs, "export function howGreat() { return 'funktastic!'; }", "funky/index")

    Source importSource = Source.newBuilder("js", "import * as Module from 'funky';\n" + "Module;\n", "funky.mjs")
            .build()
    def module = context.eval(importSource)

    // The below assertion fails on Graal 20.x.
    assert module.getMetaObject() != null
}