fix: Fix slicing bug in RunEndArray (#1497)

spiraldb · Nov 28, 2024 · 1b62acf · 1b62acf
1 parent 1844de1
commit 1b62acf
Showing 1 changed file with 33 additions and 5 deletions.
diff --git a/encodings/runend/src/compute/mod.rs b/encodings/runend/src/compute/mod.rs
@@ -116,15 +116,24 @@ impl TakeFn<RunEndArray> for RunEndEncoding {
 
 impl SliceFn<RunEndArray> for RunEndEncoding {
     fn slice(&self, array: &RunEndArray, start: usize, stop: usize) -> VortexResult<ArrayData> {
-        let slice_begin = array.find_physical_index(start)?;
-        let slice_end = array.find_physical_index(stop)?;
+        let new_length = stop - start;
+
+        let (slice_begin, slice_end) = if new_length == 0 {
+            let values_len = array.values().len();
+            (values_len, values_len)
+        } else {
+            let physical_start = array.find_physical_index(start)?;
+            let physical_stop = array.find_physical_index(stop)?;
+
+            (physical_start, physical_stop + 1)
+        };
 
         Ok(RunEndArray::with_offset_and_length(
-            slice(array.ends(), slice_begin, slice_end + 1)?,
-            slice(array.values(), slice_begin, slice_end + 1)?,
+            slice(array.ends(), slice_begin, slice_end)?,
+            slice(array.values(), slice_begin, slice_end)?,
             array.validity().slice(start, stop)?,
             start + array.offset(),
-            stop - start,
+            new_length,
         )?
         .into_array())
     }
@@ -407,6 +416,25 @@ mod test {
         );
     }
 
+    #[test]
+    fn slice_at_end() {
+        let re_array = RunEndArray::try_new(
+            vec![7_u64, 10].into_array(),
+            vec![2_u64, 3].into_array(),
+            Validity::NonNullable,
+        )
+        .unwrap();
+
+        assert_eq!(re_array.len(), 10);
+
+        let sliced_array = slice(&re_array, re_array.len(), re_array.len()).unwrap();
+        assert!(sliced_array.is_empty());
+
+        let re_slice = RunEndArray::try_from(sliced_array).unwrap();
+        assert!(re_slice.ends().is_empty());
+        assert!(re_slice.values().is_empty())
+    }
+
     #[test]
     fn sliced_take() {
         let sliced = slice(ree_array().as_ref(), 4, 9).unwrap();