Note

Prevents NPE when converting nested arrays to strings by making DataTypeConverter re-entrancy-safe.

• In DataTypeConverter, ArrayAsStringWriter.convertAndReset and ListAsStringWriter.convertAndReset now save/restore column and appendable instead of nulling them, ensuring correct nested conversions
• Adds integration test testNestedArrayToString in DataTypeTests covering simple, CASE/WHEN with splitByChar, and deeply nested arrays to validate ResultSet#getString() on array columns

^{Written by Cursor Bugbot for commit 7694367. This will update automatically on new commits. Configure here.}