Mask null ListView take metadata

Signed-off-by: Daniel King <dan@spiraldb.com>

Author: danking

vortex-array/src/arrays/listview/compute/take.rs

@@ -50,14 +50,20 @@ fn apply_take(array: ArrayView<'_, ListView>, indices: &ArrayRef) -> VortexResul
     // duplicates.
     let nullable_new_offsets = offsets.take(indices.clone())?;
     let nullable_new_sizes = sizes.take(indices.clone())?;
+    let validity_array = new_validity.to_array(indices.len());
 
-    // `take` returns nullable arrays; cast back to non-nullable (filling with zeros to represent
-    // the null lists — the validity mask tracks nullness separately).
+    // Null output rows may carry arbitrary physical offset/size payloads from either the indices
+    // or the source rows. Mask with the final validity before filling so metadata placeholders are
+    // safe and non-nullable.
     let new_offsets = match_each_integer_ptype!(nullable_new_offsets.dtype().as_ptype(), |O| {
-        nullable_new_offsets.fill_null(Scalar::primitive(O::zero(), Nullability::NonNullable))?
+        nullable_new_offsets
+            .mask(validity_array.clone())?
+            .fill_null(Scalar::primitive(O::zero(), Nullability::NonNullable))?
     });
     let new_sizes = match_each_integer_ptype!(nullable_new_sizes.dtype().as_ptype(), |S| {
-        nullable_new_sizes.fill_null(Scalar::primitive(S::zero(), Nullability::NonNullable))?
+        nullable_new_sizes
+            .mask(validity_array.clone())?
+            .fill_null(Scalar::primitive(S::zero(), Nullability::NonNullable))?
     });
 
     // SAFETY: Take operation maintains all `ListViewArray` invariants:

vortex-array/src/arrays/listview/tests/take.rs

@@ -101,6 +101,29 @@ fn test_take_with_gaps() {
     );
 }
 
+#[test]
+fn test_take_null_source_row_zeros_offset_size_payloads() {
+    let elements = buffer![1i32, 2].into_array();
+    let offsets = buffer![0u32, 999].into_array();
+    let sizes = buffer![2u32, 999].into_array();
+    let validity = Validity::from_iter([true, false]);
+    let listview =
+        unsafe { ListViewArray::new_unchecked(elements, offsets, sizes, validity) }.into_array();
+
+    let result = listview.take(buffer![1u32].into_array()).unwrap();
+    let result_list = result
+        .execute::<ListViewArray>(&mut SESSION.create_execution_ctx())
+        .unwrap();
+
+    assert_eq!(result_list.offset_at(0), 0);
+    assert_eq!(result_list.size_at(0), 0);
+    assert!(
+        result_list
+            .is_invalid(0, &mut SESSION.create_execution_ctx())
+            .unwrap()
+    );
+}
+
 #[test]
 fn test_take_constant_arrays() {
     // ListView-specific: Test with ConstantArray for offsets/sizes.