vortex_array/arrays/null/compute/
cast.rs

1// SPDX-License-Identifier: Apache-2.0
2// SPDX-FileCopyrightText: Copyright the Vortex contributors
3
4use vortex_dtype::DType;
5use vortex_error::VortexResult;
6use vortex_error::vortex_bail;
7
8use crate::ArrayRef;
9use crate::IntoArray;
10use crate::arrays::ConstantArray;
11use crate::arrays::NullArray;
12use crate::arrays::NullVTable;
13use crate::compute::CastReduce;
14use crate::scalar::Scalar;
15
16impl CastReduce for NullVTable {
17    fn cast(array: &NullArray, dtype: &DType) -> VortexResult<Option<ArrayRef>> {
18        if !dtype.is_nullable() {
19            vortex_bail!("Cannot cast Null to {}", dtype);
20        }
21        if dtype == &DType::Null {
22            return Ok(Some(array.to_array()));
23        }
24
25        let scalar = Scalar::null(dtype.clone());
26        Ok(Some(ConstantArray::new(scalar, array.len()).into_array()))
27    }
28}
29
30#[cfg(test)]
31mod tests {
32    use rstest::rstest;
33    use vortex_dtype::DType;
34    use vortex_dtype::Nullability;
35    use vortex_dtype::PType;
36
37    use crate::arrays::NullArray;
38    use crate::builtins::ArrayBuiltins;
39    use crate::compute::conformance::cast::test_cast_conformance;
40
41    #[test]
42    fn test_cast_null_to_null() {
43        let null_array = NullArray::new(5);
44        let result = null_array.to_array().cast(DType::Null).unwrap();
45        assert_eq!(result.len(), 5);
46        assert_eq!(result.dtype(), &DType::Null);
47    }
48
49    #[test]
50    fn test_cast_null_to_nullable_succeeds() {
51        let null_array = NullArray::new(5);
52        let result = null_array
53            .to_array()
54            .cast(DType::Primitive(PType::I32, Nullability::Nullable))
55            .unwrap();
56
57        // Should create a ConstantArray of nulls
58        assert_eq!(result.len(), 5);
59        assert_eq!(
60            result.dtype(),
61            &DType::Primitive(PType::I32, Nullability::Nullable)
62        );
63
64        // Verify all values are null
65        for i in 0..5 {
66            assert!(result.scalar_at(i).unwrap().is_null());
67        }
68    }
69
70    #[test]
71    fn test_cast_null_to_non_nullable_fails() {
72        let null_array = NullArray::new(5);
73        let result = null_array
74            .to_array()
75            .cast(DType::Primitive(PType::I32, Nullability::NonNullable));
76        assert!(result.is_err());
77    }
78
79    #[rstest]
80    #[case(NullArray::new(5))]
81    #[case(NullArray::new(1))]
82    #[case(NullArray::new(100))]
83    #[case(NullArray::new(0))]
84    fn test_cast_null_conformance(#[case] array: NullArray) {
85        test_cast_conformance(array.as_ref());
86    }
87}
vortex_array/arrays/null/compute/cast.rs

vortex_array/arrays/null/compute/
cast.rs
