robtandy opened a new issue, #13860:
URL: https://github.com/apache/datafusion/issues/13860
### Describe the bug
Substrait round trip fails for a query that produces a logical plan where
the Sort node includes a fetch.
As an example,
```
Sort: data.b ASC NULLS LAST, fetch=2
Filter: data.a > Int64(1)
TableScan: data projection=[a, b, c, d, e, f], partial_filters=[data.a >
Int64(1)]
```
Upon returning from the round trip produces
```
Sort: data.b ASC NULLS LAST
Filter: data.a > Int64(1)
TableScan: data projection=[a, b, c, d, e, f], partial_filters=[data.a >
Int64(1)]
```
the fetch is lost.
I'm happy to take and fix this issue, but I wasn't sure where the fix should
be made. Should this fix the Sort Rel in substrait that cannot hold a `fetch`
member? Or should this be a fix in the substrait producer to produce a plan
with a Limit and a Sort?
### To Reproduce
Add a test to `datafusion/substrait/tests/cases/round_trip_logical_plan.rs`
such as
```rust
#[tokio::test]
async fn select_with_filter_sort_limit() -> Result<()> {
roundtrip("SELECT * FROM data WHERE a > 1 ORDER BY b ASC LIMIT 2").await
}
```
in this repo, run
```shell
cd datafusion/substrait
cargo test -- --nocapture select_with_filter_sort_limit
```
### Expected behavior
A round trip for this plan should work.
### Additional context
_No response_
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