[Variant] extend shredded null handling for arrays #8400
Description
@alamb -- we should track a follow-on item somewhere: Once we support array element shredding, we will have three different semantics to deal with, and this fix will need to expand from a bool to an enum:
When appending NULL:
| struct | value | typed_value | |
|---|---|---|---|
| Variant | NULL | NULL | NULL |
| Object field | valid | NULL | NULL |
| Array element | valid | Variant::Null | NULL |
Originally posted by @scovich in #8395 (comment)