NPE when using not null KProperty to update data with nulls

[koperagen]

So this code

@DataSchema
interface Schema {
    val i: Int
}

val df = dataFrameOf("i")(1, null)

df.fillNulls(Schema::i).with { 42 }

causes java.lang.NullPointerException More generic example (fillNulls uses update): df.update(Schema::i).with { 42 }.

fillNulls can avoid throwing exception. Not sure what to do about update. Maybe more meaningful error message