HyukjinKwon opened a new pull request, #48769:
URL: https://github.com/apache/arrow/pull/48769
### Rationale for this change
Closes ARROW-18281, which has been open since 2022. The `list_slice` kernel
currently rejects `start == stop`, but should return empty lists instead
(following Python slicing semantics).
The underlying implementation already handles this case correctly. When
ARROW-18282 added step support, the formula `bit_util::CeilDiv(stop - start,
step)` naturally returns 0 for `start == stop`, producing empty lists. The only
issue was an overly restrictive validation check (`start >= stop`) that
prevented this from working.
### What changes are included in this PR?
- Changed validation from `start >= stop` to `start > stop`
- Updated error message
- Added test cases
### Are these changes tested?
Yes, tests were added.
### Are there any user-facing changes?
Yes.
```python
import pyarrow as pa
pc.list_slice([[1,2,3]], 0, 0)
```
Before:
```
pyarrow.lib.ArrowInvalid: `start`(0) should be greater than 0 and smaller
than `stop`(0)
```
After:
```
<pyarrow.lib.ListArray object at 0x1a01b8b20>
[
[]
]
```
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