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Ensure null inputs to array setop functions return null output #19683

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1581857
Ensure null inputs to array setop functions return null output
Jefffrey Jan 7, 2026
455043d
doc update
Jefffrey Jan 7, 2026
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46 changes: 35 additions & 11 deletions datafusion/functions-nested/src/except.rs
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -15,11 +15,12 @@
// specific language governing permissions and limitations
// under the License.

//! [`ScalarUDFImpl`] definitions for array_except function.
//! [`ScalarUDFImpl`] definition for array_except function.

use crate::utils::{check_datatypes, make_scalar_function};
use arrow::array::new_null_array;
use arrow::array::{Array, ArrayRef, GenericListArray, OffsetSizeTrait, cast::AsArray};
use arrow::buffer::OffsetBuffer;
use arrow::buffer::{NullBuffer, OffsetBuffer};
use arrow::datatypes::{DataType, FieldRef};
use arrow::row::{RowConverter, SortField};
use datafusion_common::utils::{ListCoercion, take_function_args};
Expand All @@ -28,6 +29,7 @@ use datafusion_expr::{
ColumnarValue, Documentation, ScalarUDFImpl, Signature, Volatility,
};
use datafusion_macros::user_doc;
use itertools::Itertools;
use std::any::Any;
use std::sync::Arc;

Expand Down Expand Up @@ -104,8 +106,11 @@ impl ScalarUDFImpl for ArrayExcept {
}

fn return_type(&self, arg_types: &[DataType]) -> Result<DataType> {
match (&arg_types[0].clone(), &arg_types[1].clone()) {
(DataType::Null, _) | (_, DataType::Null) => Ok(arg_types[0].clone()),
match (&arg_types[0], &arg_types[1]) {
(DataType::Null, DataType::Null) => {
Ok(DataType::new_list(DataType::Null, true))
}
(DataType::Null, dt) | (dt, DataType::Null) => Ok(dt.clone()),
(dt, _) => Ok(dt.clone()),
}
}
Expand All @@ -129,8 +134,16 @@ impl ScalarUDFImpl for ArrayExcept {
fn array_except_inner(args: &[ArrayRef]) -> Result<ArrayRef> {
let [array1, array2] = take_function_args("array_except", args)?;

let len = array1.len();
match (array1.data_type(), array2.data_type()) {
(DataType::Null, _) | (_, DataType::Null) => Ok(array1.to_owned()),
(DataType::Null, DataType::Null) => Ok(new_null_array(
&DataType::new_list(DataType::Null, true),
len,
)),
(DataType::Null, dt @ DataType::List(_))
| (DataType::Null, dt @ DataType::LargeList(_))
| (dt @ DataType::List(_), DataType::Null)
| (dt @ DataType::LargeList(_), DataType::Null) => Ok(new_null_array(dt, len)),
(DataType::List(field), DataType::List(_)) => {
check_datatypes("array_except", &[array1, array2])?;
let list1 = array1.as_list::<i32>();
Expand Down Expand Up @@ -169,14 +182,25 @@ fn general_except<OffsetSize: OffsetSizeTrait>(
let mut rows = Vec::with_capacity(l_values.num_rows());
let mut dedup = HashSet::new();

for (l_w, r_w) in l.offsets().windows(2).zip(r.offsets().windows(2)) {
let l_slice = l_w[0].as_usize()..l_w[1].as_usize();
let r_slice = r_w[0].as_usize()..r_w[1].as_usize();
for i in r_slice {
let nulls = NullBuffer::union(l.nulls(), r.nulls());

for (i, ((l_start, l_end), (r_start, r_end))) in l
.offsets()
.iter()
.tuple_windows()
.zip(r.offsets().iter().tuple_windows())
.enumerate()
{
if nulls.as_ref().is_some_and(|nulls| nulls.is_null(i)) {
offsets.push(OffsetSize::usize_as(rows.len()));
continue;
}

for i in r_start.as_usize()..r_end.as_usize() {
let right_row = r_values.row(i);
dedup.insert(right_row);
}
for i in l_slice {
for i in l_start.as_usize()..l_end.as_usize() {
let left_row = l_values.row(i);
if dedup.insert(left_row) {
rows.push(left_row);
Expand All @@ -192,7 +216,7 @@ fn general_except<OffsetSize: OffsetSizeTrait>(
field.to_owned(),
OffsetBuffer::new(offsets.into()),
values.to_owned(),
l.nulls().cloned(),
nulls,
))
} else {
internal_err!("array_except failed to convert rows")
Expand Down
109 changes: 27 additions & 82 deletions datafusion/functions-nested/src/set_ops.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -19,8 +19,7 @@

use crate::utils::make_scalar_function;
use arrow::array::{
Array, ArrayRef, GenericListArray, LargeListArray, ListArray, OffsetSizeTrait,
new_null_array,
Array, ArrayRef, GenericListArray, OffsetSizeTrait, new_empty_array, new_null_array,
};
use arrow::buffer::{NullBuffer, OffsetBuffer};
use arrow::compute;
Expand Down Expand Up @@ -69,7 +68,7 @@ make_udf_expr_and_func!(

#[user_doc(
doc_section(label = "Array Functions"),
description = "Returns an array of elements that are present in both arrays (all elements from both arrays) with out duplicates.",
description = "Returns an array of elements that are present in both arrays (all elements from both arrays) without duplicates.",
syntax_example = "array_union(array1, array2)",
sql_example = r#"```sql
> select array_union([1, 2, 3, 4], [5, 6, 3, 4]);
Expand Down Expand Up @@ -136,8 +135,7 @@ impl ScalarUDFImpl for ArrayUnion {
let [array1, array2] = take_function_args(self.name(), arg_types)?;
match (array1, array2) {
(Null, Null) => Ok(DataType::new_list(Null, true)),
(Null, dt) => Ok(dt.clone()),
(dt, Null) => Ok(dt.clone()),
(Null, dt) | (dt, Null) => Ok(dt.clone()),
(dt, _) => Ok(dt.clone()),
}
}
Expand Down Expand Up @@ -221,8 +219,7 @@ impl ScalarUDFImpl for ArrayIntersect {
let [array1, array2] = take_function_args(self.name(), arg_types)?;
match (array1, array2) {
(Null, Null) => Ok(DataType::new_list(Null, true)),
(Null, dt) => Ok(dt.clone()),
(dt, Null) => Ok(dt.clone()),
(Null, dt) | (dt, Null) => Ok(dt.clone()),
(dt, _) => Ok(dt.clone()),
}
}
Expand Down Expand Up @@ -363,23 +360,19 @@ fn generic_set_lists<OffsetSize: OffsetSizeTrait>(

let mut offsets = vec![OffsetSize::usize_as(0)];
let mut new_arrays = vec![];
let mut new_null_buf = vec![];
let converter = RowConverter::new(vec![SortField::new(l.value_type())])?;
for (first_arr, second_arr) in l.iter().zip(r.iter()) {
let mut ele_should_be_null = false;
for (l_arr, r_arr) in l.iter().zip(r.iter()) {
let last_offset = *offsets.last().unwrap();

let l_values = if let Some(first_arr) = first_arr {
converter.convert_columns(&[first_arr])?
} else {
ele_should_be_null = true;
converter.empty_rows(0, 0)
};

let r_values = if let Some(second_arr) = second_arr {
converter.convert_columns(&[second_arr])?
} else {
ele_should_be_null = true;
converter.empty_rows(0, 0)
let (l_values, r_values) = match (l_arr, r_arr) {
(Some(l_arr), Some(r_arr)) => (
converter.convert_columns(&[l_arr])?,
converter.convert_columns(&[r_arr])?,
),
_ => {
Comment on lines -371 to +372
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Contributor Author

@Jefffrey Jefffrey Jan 7, 2026

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Little drive-by refactor here to skip the set logic below for nulls

offsets.push(last_offset);
continue;
}
};

let l_iter = l_values.iter().sorted().dedup();
Expand All @@ -405,11 +398,6 @@ fn generic_set_lists<OffsetSize: OffsetSizeTrait>(
}
}

let last_offset = match offsets.last() {
Some(offset) => *offset,
None => return internal_err!("offsets should not be empty"),
};

offsets.push(last_offset + OffsetSize::usize_as(rows.len()));
let arrays = converter.convert_rows(rows)?;
let array = match arrays.first() {
Expand All @@ -419,18 +407,21 @@ fn generic_set_lists<OffsetSize: OffsetSizeTrait>(
}
};

new_null_buf.push(!ele_should_be_null);
new_arrays.push(array);
}

let offsets = OffsetBuffer::new(offsets.into());
let new_arrays_ref: Vec<_> = new_arrays.iter().map(|v| v.as_ref()).collect();
let values = compute::concat(&new_arrays_ref)?;
let values = if new_arrays_ref.is_empty() {
new_empty_array(&l.value_type())
} else {
compute::concat(&new_arrays_ref)?
};
let arr = GenericListArray::<OffsetSize>::try_new(
field,
offsets,
values,
Some(NullBuffer::new(new_null_buf.into())),
NullBuffer::union(l.nulls(), r.nulls()),
)?;
Ok(Arc::new(arr))
}
Expand All @@ -440,59 +431,13 @@ fn general_set_op(
array2: &ArrayRef,
set_op: SetOp,
) -> Result<ArrayRef> {
fn empty_array(data_type: &DataType, len: usize, large: bool) -> Result<ArrayRef> {
let field = Arc::new(Field::new_list_field(data_type.clone(), true));
let values = new_null_array(data_type, len);
if large {
Ok(Arc::new(LargeListArray::try_new(
field,
OffsetBuffer::new_zeroed(len),
values,
None,
)?))
} else {
Ok(Arc::new(ListArray::try_new(
field,
OffsetBuffer::new_zeroed(len),
values,
None,
)?))
}
}

let len = array1.len();
match (array1.data_type(), array2.data_type()) {
(Null, Null) => Ok(Arc::new(ListArray::new_null(
Arc::new(Field::new_list_field(Null, true)),
array1.len(),
))),
(Null, List(field)) => {
if set_op == SetOp::Intersect {
return empty_array(field.data_type(), array1.len(), false);
}
let array = as_list_array(&array2)?;
general_array_distinct::<i32>(array, field)
}
(List(field), Null) => {
if set_op == SetOp::Intersect {
return empty_array(field.data_type(), array1.len(), false);
}
let array = as_list_array(&array1)?;
general_array_distinct::<i32>(array, field)
}
(Null, LargeList(field)) => {
if set_op == SetOp::Intersect {
return empty_array(field.data_type(), array1.len(), true);
}
let array = as_large_list_array(&array2)?;
general_array_distinct::<i64>(array, field)
}
(LargeList(field), Null) => {
if set_op == SetOp::Intersect {
return empty_array(field.data_type(), array1.len(), true);
}
let array = as_large_list_array(&array1)?;
general_array_distinct::<i64>(array, field)
}
(Null, Null) => Ok(new_null_array(&DataType::new_list(Null, true), len)),
(Null, dt @ List(_))
| (Null, dt @ LargeList(_))
| (dt @ List(_), Null)
| (dt @ LargeList(_), Null) => Ok(new_null_array(dt, len)),
(List(field), List(_)) => {
let array1 = as_list_array(&array1)?;
let array2 = as_list_array(&array2)?;
Expand Down
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