fix sparse array in the no-patches case

Author: danking

encodings/sparse/src/compute/take.rs

@@ -8,7 +8,12 @@ use crate::{SparseArray, SparseEncoding};
 impl TakeFn<SparseArray> for SparseEncoding {
     fn take(&self, array: &SparseArray, take_indices: &Array) -> VortexResult<Array> {
         let Some(new_patches) = array.patches().take(take_indices)? else {
-            return Ok(ConstantArray::new(array.fill_scalar(), take_indices.len()).into_array());
+            let result_nullability =
+                array.dtype().nullability() | take_indices.dtype().nullability();
+            let result_fill_scalar = array
+                .fill_scalar()
+                .cast(&array.dtype().with_nullability(result_nullability))?;
+            return Ok(ConstantArray::new(result_fill_scalar, take_indices.len()).into_array());
         };
 
         SparseArray::try_new_from_patches(new_patches, take_indices.len(), array.fill_scalar())

vortex-array/src/compute/take.rs

@@ -113,12 +113,15 @@ pub fn take(array: impl AsRef<Array>, indices: impl AsRef<Array>) -> VortexResul
     #[cfg(debug_assertions)]
     {
         // If either the indices or the array are nullable, the result should be nullable.
-        let expected_nullability =
-            (indices.dtype().is_nullable() || array.dtype().is_nullable()).into();
+        let expected_nullability = indices.dtype().nullability() | array.dtype().nullability();
         assert_eq!(
             taken.dtype(),
             &array.dtype().with_nullability(expected_nullability),
-            "Take result should be nullable if either the indices or the array are nullable"
+            "Take result ({}) should be nullable if either the indices ({}) or the array ({}) are nullable. ({})",
+            taken.dtype(),
+            indices.dtype().nullability().verbose_display(),
+            array.dtype().nullability().verbose_display(),
+            array.encoding(),
         );
     }
 
@@ -140,10 +143,11 @@ pub fn take_into(
         assert_eq!(
             builder.dtype(),
             &array.dtype().with_nullability(expected_nullability),
-            "Take_into result ({}) should be nullable if, and only if, either the indices ({}) or the array are nullable ({})",
+            "Take_into result ({}) should be nullable if, and only if, either the indices ({}) or the array ({}) are nullable. ({})",
             builder.dtype(),
             indices.dtype().nullability().verbose_display(),
             array.dtype().nullability().verbose_display(),
+            array.encoding(),
         );
     }