fix: first none/empty list in ListArray panics in `cast_with_option…

…s` (#7065)

* fix: first none in `ListArray` panics in `cast_with_options`

* simplify

* fix

* Update arrow-cast/src/cast/list.rs

Co-authored-by: Jeffrey Vo <jeffrey.vo.australia@gmail.com>

---------

Co-authored-by: Jeffrey Vo <jeffrey.vo.australia@gmail.com>

arrow-cast/src/cast/list.rs

@@ -88,6 +88,17 @@ where
     let mut mutable = MutableArrayData::new(vec![&values], nullable, cap);
     // The end position in values of the last incorrectly-sized list slice
     let mut last_pos = 0;
+
+    // Need to flag when previous vector(s) are empty/None to distinguish from 'All slices were correct length' cases.
+    let is_prev_empty = if array.offsets().len() < 2 {
+        false
+    } else {
+        let first_offset = array.offsets()[0].as_usize();
+        let second_offset = array.offsets()[1].as_usize();
+
+        first_offset == 0 && second_offset == 0
+    };
+
     for (idx, w) in array.offsets().windows(2).enumerate() {
         let start_pos = w[0].as_usize();
         let end_pos = w[1].as_usize();
@@ -113,7 +124,7 @@ where
     }
 
     let values = match last_pos {
-        0 => array.values().slice(0, cap), // All slices were the correct length
+        0 if !is_prev_empty => array.values().slice(0, cap), // All slices were the correct length
         _ => {
             if mutable.len() != cap {
                 // Remaining slices were all correct length

arrow-cast/src/cast/mod.rs

@@ -9952,4 +9952,41 @@ mod tests {
         assert_eq!(result.unwrap_err().to_string(),
                    "Invalid argument error: 123456789 is too large to store in a Decimal256 of precision 6. Max is 999999");
     }
+
+    #[test]
+    fn test_first_none() {
+        let array = Arc::new(ListArray::from_iter_primitive::<Int64Type, _, _>(vec![
+            None,
+            Some(vec![Some(1), Some(2)]),
+        ])) as ArrayRef;
+        let data_type =
+            DataType::FixedSizeList(FieldRef::new(Field::new("item", DataType::Int64, true)), 2);
+        let opt = CastOptions::default();
+        let r = cast_with_options(&array, &data_type, &opt).unwrap();
+
+        let fixed_array = Arc::new(FixedSizeListArray::from_iter_primitive::<Int64Type, _, _>(
+            vec![None, Some(vec![Some(1), Some(2)])],
+            2,
+        )) as ArrayRef;
+        assert_eq!(*fixed_array, *r);
+    }
+
+    #[test]
+    fn test_first_last_none() {
+        let array = Arc::new(ListArray::from_iter_primitive::<Int64Type, _, _>(vec![
+            None,
+            Some(vec![Some(1), Some(2)]),
+            None,
+        ])) as ArrayRef;
+        let data_type =
+            DataType::FixedSizeList(FieldRef::new(Field::new("item", DataType::Int64, true)), 2);
+        let opt = CastOptions::default();
+        let r = cast_with_options(&array, &data_type, &opt).unwrap();
+
+        let fixed_array = Arc::new(FixedSizeListArray::from_iter_primitive::<Int64Type, _, _>(
+            vec![None, Some(vec![Some(1), Some(2)]), None],
+            2,
+        )) as ArrayRef;
+        assert_eq!(*fixed_array, *r);
+    }
 }