Trying to call "PreparedStatement.run()" throws "Cannot invoke "calcite.schema.Schema.getTable(String)" because the return value of "calcite.schema.SchemaPlus.getSubSchema(String)" is null"

[Gavin Ray]

Unsure of where this is coming from/how to debug it.
(The code I am using is below, taken from Calcite examples)

If I print out the sub-schema names of "rootSchema", and their tables, I
get:

    subSchemaNames: [hr, metadata]
    "hr" subSchema table names: [depts, emps]
    "metadata" subSchema table names: [COLUMNS, TABLES]

So I am not certain what value is being passed that it would fail
a "schema.getSubSchema()" call, or where to put a breakpoint to debug that.

Does anyone spot something I'm doing that's clearly wrong, or have an idea
where I could look to find the code that's causing this?

Stacktrace winds up at "Baz", so I think it's generated code
Thank you
===========================================================

fun main(args: Array<String>) {
    val hr = Frameworks.createRootSchema(true).add("hr",
HrClusteredSchema())

    val frameworkConfig: FrameworkConfig = Frameworks
        .newConfigBuilder()
        .parserConfig(SqlParser.config().withCaseSensitive(false))
        .defaultSchema(hr)
        .build()

    Frameworks.withPlanner(::test, frameworkConfig)
}

fun test(cluster: RelOptCluster, relOptSchema: RelOptSchema, rootSchema:
Schema) {
    val planner = cluster.planner
    val relBuilder: RelBuilder =
        RelFactories.LOGICAL_BUILDER.create(cluster, relOptSchema)

    val relRoot: RelNode = // ...
    val desiredTraits =
cluster.traitSet().replace(EnumerableConvention.INSTANCE)
    val newRoot = cluster.planner.changeTraits(relRoot, desiredTraits)

    cluster.planner.root = newRoot
    val bestExp = cluster.planner.findBestExp()
    val run = RelRunners.run(bestExp)
    val resultSet = run.executeQuery()
}