Building nullable/non nullable ListArrays

[adriangb]

I’m trying to build ListArrays with various combinations of null ability for the outer and inner items, but it seems that the builder functions hardcode the assumption that it’s nullable (eg here

arrow-rs/arrow-array/src/builder/generic_list_builder.rs

Line 137 in 79bda7d

true, // TODO: find a consistent way of getting this

). It seems like I’ll have to drop down to the buffer level, but that’s complicated. Is there an easier way?

[Jefffrey]

This is now possible, can use GenericListBuilder::with_field() to override the default field (which sets nullability to true):

arrow-rs/arrow-array/src/builder/generic_list_builder.rs

Lines 298 to 301 in c245a45

	let field = match &self.field {
	Some(f) => f.clone(),
	None => Arc::new(Field::new_list_field(values.data_type().clone(), true)),
	};