vortex_array/arrays/dict/compute/
cast.rs

1// SPDX-License-Identifier: Apache-2.0
2// SPDX-FileCopyrightText: Copyright the Vortex contributors
3
4use vortex_error::VortexResult;
5
6use super::Dict;
7use super::DictArray;
8use crate::ArrayRef;
9use crate::IntoArray;
10use crate::array::ArrayView;
11use crate::arrays::dict::DictArrayExt;
12use crate::arrays::dict::DictArraySlotsExt;
13use crate::builtins::ArrayBuiltins;
14use crate::dtype::DType;
15use crate::scalar_fn::fns::cast::CastReduce;
16
17impl CastReduce for Dict {
18    fn cast(array: ArrayView<'_, Dict>, dtype: &DType) -> VortexResult<Option<ArrayRef>> {
19        // Can have un-reference null values making the cast of values fail without a possible mask.
20        // TODO(joe): optimize this, could look at accessible values and fill_null not those?
21        if !dtype.is_nullable() && !array.values().validity()?.definitely_no_nulls() {
22            return Ok(None);
23        }
24        // Cast the dictionary values to the target type
25        let casted_values = array.values().cast(dtype.clone())?;
26
27        // If the codes are nullable but we are casting to non nullable dtype we have to remove nullability from codes as well
28        let casted_codes = if array.codes().dtype().is_nullable() && !dtype.is_nullable() {
29            array
30                .codes()
31                .cast(array.codes().dtype().with_nullability(dtype.nullability()))?
32        } else {
33            array.codes().clone()
34        };
35
36        // SAFETY: casting does not alter invariants of the codes
37        Ok(Some(
38            unsafe {
39                DictArray::new_unchecked(casted_codes, casted_values)
40                    .set_all_values_referenced(array.has_all_values_referenced())
41            }
42            .into_array(),
43        ))
44    }
45}
46
47#[cfg(test)]
48mod tests {
49    use std::sync::LazyLock;
50
51    use rstest::rstest;
52    use vortex_buffer::BitBuffer;
53    use vortex_buffer::buffer;
54    use vortex_session::VortexSession;
55
56    use crate::ArrayRef;
57    use crate::IntoArray;
58    use crate::VortexSessionExecute;
59    use crate::arrays::Dict;
60    use crate::arrays::DictArray;
61    use crate::arrays::PrimitiveArray;
62    use crate::arrays::dict::DictArraySlotsExt;
63    use crate::assert_arrays_eq;
64    use crate::builders::dict::dict_encode;
65    use crate::builtins::ArrayBuiltins;
66    use crate::compute::conformance::cast::test_cast_conformance;
67    use crate::dtype::DType;
68    use crate::dtype::Nullability;
69    use crate::dtype::PType;
70    use crate::validity::Validity;
71
72    static SESSION: LazyLock<VortexSession> = LazyLock::new(crate::array_session);
73
74    #[test]
75    fn test_cast_dict_to_wider_type() {
76        let ctx = &mut SESSION.create_execution_ctx();
77        let values = buffer![1i32, 2, 3, 2, 1].into_array();
78        let dict = dict_encode(&values, ctx).unwrap();
79
80        let casted = dict
81            .into_array()
82            .cast(DType::Primitive(PType::I64, Nullability::NonNullable))
83            .unwrap();
84        assert_eq!(
85            casted.dtype(),
86            &DType::Primitive(PType::I64, Nullability::NonNullable)
87        );
88
89        let decoded = casted.into_array().execute::<PrimitiveArray>(ctx).unwrap();
90        assert_arrays_eq!(decoded, PrimitiveArray::from_iter([1i64, 2, 3, 2, 1]), ctx);
91    }
92
93    #[test]
94    fn test_cast_dict_nullable() {
95        let values =
96            PrimitiveArray::from_option_iter([Some(10i32), None, Some(20), Some(10), None]);
97        let dict = dict_encode(&values.into_array(), &mut SESSION.create_execution_ctx()).unwrap();
98
99        let casted = dict
100            .into_array()
101            .cast(DType::Primitive(PType::I64, Nullability::Nullable))
102            .unwrap();
103        assert_eq!(
104            casted.dtype(),
105            &DType::Primitive(PType::I64, Nullability::Nullable)
106        );
107    }
108
109    #[test]
110    fn test_cast_dict_allvalid_to_nonnullable_and_back() {
111        let ctx = &mut SESSION.create_execution_ctx();
112        // Create an AllValid dict array (no nulls)
113        let values = buffer![10i32, 20, 30, 40].into_array();
114        let dict = dict_encode(&values, ctx).unwrap();
115
116        // Verify initial state - codes should be NonNullable, values should be NonNullable
117        assert_eq!(dict.codes().dtype().nullability(), Nullability::NonNullable);
118        assert_eq!(
119            dict.values().dtype().nullability(),
120            Nullability::NonNullable
121        );
122
123        // Cast to NonNullable (should be identity since already NonNullable)
124        let non_nullable = dict
125            .clone()
126            .into_array()
127            .cast(DType::Primitive(PType::I32, Nullability::NonNullable))
128            .unwrap();
129        assert_eq!(
130            non_nullable.dtype(),
131            &DType::Primitive(PType::I32, Nullability::NonNullable)
132        );
133
134        // Check that codes and values are still NonNullable
135        let non_nullable_dict = non_nullable.as_::<Dict>();
136        assert_eq!(
137            non_nullable_dict.codes().dtype().nullability(),
138            Nullability::NonNullable
139        );
140        assert_eq!(
141            non_nullable_dict.values().dtype().nullability(),
142            Nullability::NonNullable
143        );
144
145        // Cast to Nullable
146        let nullable = non_nullable
147            .cast(DType::Primitive(PType::I32, Nullability::Nullable))
148            .unwrap();
149        assert_eq!(
150            nullable.dtype(),
151            &DType::Primitive(PType::I32, Nullability::Nullable)
152        );
153
154        // Check that both codes and values are now Nullable
155        let nullable_dict = nullable.as_::<Dict>();
156        assert_eq!(
157            nullable_dict.codes().dtype().nullability(),
158            Nullability::NonNullable
159        );
160        assert_eq!(
161            nullable_dict.values().dtype().nullability(),
162            Nullability::Nullable
163        );
164
165        // Cast back to NonNullable
166        let back_to_non_nullable = nullable
167            .cast(DType::Primitive(PType::I32, Nullability::NonNullable))
168            .unwrap();
169        assert_eq!(
170            back_to_non_nullable.dtype(),
171            &DType::Primitive(PType::I32, Nullability::NonNullable)
172        );
173
174        // Verify values are unchanged
175        let original_values = dict.into_array().execute::<PrimitiveArray>(ctx).unwrap();
176
177        let final_values = back_to_non_nullable.execute::<PrimitiveArray>(ctx).unwrap();
178        assert_arrays_eq!(original_values, final_values, ctx);
179    }
180
181    #[rstest]
182    #[case(dict_encode(&buffer![1i32, 2, 3, 2, 1, 3].into_array(), &mut SESSION.create_execution_ctx()).unwrap().into_array())]
183    #[case(dict_encode(&buffer![100u32, 200, 100, 300, 200].into_array(), &mut SESSION.create_execution_ctx()).unwrap().into_array())]
184    #[case(dict_encode(&PrimitiveArray::from_option_iter([Some(1i32), None, Some(2), Some(1), None]).into_array(), &mut SESSION.create_execution_ctx()).unwrap().into_array())]
185    #[case(dict_encode(&buffer![1.5f32, 2.5, 1.5, 3.5].into_array(), &mut SESSION.create_execution_ctx()).unwrap().into_array())]
186    fn test_cast_dict_conformance(#[case] array: ArrayRef) {
187        test_cast_conformance(&array);
188    }
189
190    #[test]
191    fn test_cast_dict_with_unreferenced_null_values_to_nonnullable() {
192        let ctx = &mut SESSION.create_execution_ctx();
193        // Create a dict with nullable values that have unreferenced null entries.
194        // Values: [1.0, null, 3.0] (index 1 is null but no code points to it)
195        // Codes: [0, 2, 0] (only reference indices 0 and 2, never 1)
196        let values = PrimitiveArray::new(
197            buffer![1.0f64, 0.0f64, 3.0f64],
198            Validity::from(BitBuffer::from(vec![true, false, true])),
199        )
200        .into_array();
201        let codes = buffer![0u32, 2, 0].into_array();
202        let dict = DictArray::try_new(codes, values).unwrap();
203
204        // The dict is Nullable (because values are nullable), but all codes point to valid values.
205        assert_eq!(
206            dict.dtype(),
207            &DType::Primitive(PType::F64, Nullability::Nullable)
208        );
209
210        // Casting to NonNullable should succeed since all logical values are non-null.
211        let result = dict
212            .into_array()
213            .cast(DType::Primitive(PType::F64, Nullability::NonNullable));
214        assert!(
215            result.is_ok(),
216            "cast to NonNullable should succeed for dict with only unreferenced null values"
217        );
218        let casted = result.unwrap();
219        assert_eq!(
220            casted.dtype(),
221            &DType::Primitive(PType::F64, Nullability::NonNullable)
222        );
223        assert_arrays_eq!(casted, PrimitiveArray::from_iter([1.0f64, 3.0, 1.0]), ctx);
224    }
225}
vortex_array/arrays/dict/compute/cast.rs

vortex_array/arrays/dict/compute/
cast.rs
