Files
lancedb/nodejs/lancedb
Drew Gallardo 65cd142c7e feat: add remote branch diff and merge client APIs (#3686)
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>
2026-07-18 12:38:05 -07:00
..