This PR adds some support for `diff` / `merge` in the remote client as
for local tables we stay `NotSupported` until
https://github.com/lance-format/lance/issues/7263.
This wires the two review-and-land calls against the remote REST API:
- `POST /v1/table/{id}/branches/diff`
- `POST /v1/table/{id}/branches/merge`
Rust gets typed results (`BranchDiff`, `MergeBranchResult`). Python
returns the wire JSON, same shape as the REST response.
Merge here means promoting a branch's added columns onto `main`.
### Behavior
- Remote only. Local raises `NotSupported`.
- A rejected merge is not an exception. HTTP 409 still returns `Ok` / a
dict with `status="rejected"` and blockers in `diff.mergeBlockers`.
- Unknown blocker / status codes parse as `Unknown` so a newer server
does not break older clients.
- `MergePreview` tolerates missing fields for the same reason.
- Merge requests are not retried. 409 is final and carries the body you
need.
### Example
```python
table = db.open_table("images")
table.branches.create("exp")
exp = table.branches.checkout("exp")
exp.add_columns({"tag": "cast('draft' as string)"})
diff = table.branches.diff("exp")
preview = table.branches.merge("exp", dry_run=True)
result = table.branches.merge("exp", dry_run=False)
if result["status"] == "merged":
print("landed at", result["mainVersionAfter"])
elif result["status"] == "rejected":
print(result["diff"]["mergeBlockers"])
```
### Testing
cargo test -p lancedb --features remote diff_branch
cargo test -p lancedb --features remote merge_branch
---------
Co-authored-by: Cursor <cursoragent@cursor.com>
This PR is for the Read path against blob v2. #3528 handles declare +
write, and this this adds materialization on local tables.
- blob_columns()
- fetch_blobs(column, row_ids) → bytes
- fetch_blob_files(column, row_ids) → lazy handles
- Pass _rowid from query().with_row_id(). Remote returns NotSupported.
(for now)
### Use cases
search, grab row ids, materialize images:
```rust
let row_ids = /* _rowid from hits */;
let images = table.fetch_blobs("image", &row_ids).await?;
```
Large blobs: open handles, read only what you need:
```rust
let handles = table.fetch_blob_files("image", &row_ids).await?;
let bytes = handles[0].as_ref().unwrap().read().await?;
```
Filter then batch fetch: collect ids from a filter, one call.
Multiple blob columns: image and thumbnail independently.
Row ids from before compact: still resolve.
### Alignment note
Lance `read_blobs` drops null rows. We descriptor-take first, read
non-null ids, re-expand to match input order. Null and zero-length blobs
come back null/None. Bytes path sets `preserve_order(true)`. So I added:
```
TODO(lance): expose selection_index or an aligned execute so we can drop the pre-read.
```
### Tests
`cargo test -p lancedb --test blob_integration`
- 30 tests covering nulls, reorder, dups, cross-fragment bytes + files,
compact, delete, legacy v1 errors.
---------
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
This PR fixes a flaky test I hit on Windows test in #3528.
Looks like `test_eventual_consistency_background_refresh` was failing
with `v_cached` expected 1, got 2. There was a pr which swapped
`tokio::time::sleep(300ms)` for `clock::advance_by(300ms)`, which is
pretty much fine but the test necer pinned the clock so the first
`get()` locks the `cached_at` on wall time. Therefore, if our CI is
taking long enough the ttl expires before the value assertion in the
test.
So now we can add a `pin()` and call it first `get()`. After that we can
advance the clock manually with no problems.
Also, it's worth noting that I tried pinning in `BackgroundCache::new()`
first. That broke another test `test_reload_resets_consistency_timer`,
which uses real `tokio::time::sleep` and needs wall clock after
`clear_mock()`. So the pin stays in this test only. And this should
unblock us.
Failing instances:
-
https://github.com/lancedb/lancedb/actions/runs/27567527236/job/81495265474?pr=3528
-
https://github.com/lancedb/lancedb/actions/runs/27560366489/job/81470414928
Drew GallardoandCursor
