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Mohammad Hijjawi
580240278f
## Summary
A synchronous hybrid query without an explicit `.limit()` can return up
to 20 rows. The documented default is 10, and `AsyncHybridQuery` already
falls back to `DEFAULT_HYBRID_LIMIT` (10).
In `LanceHybridQueryBuilder`, each sub-query (vector and FTS) falls back
to its own default of 10 rows. The fused result was then sliced with
`limit=None`, i.e. not truncated at all. When the two legs match
different rows, the caller gets the union.
t = db.create_table("t", [{"text": ("dog" if i >= 20 else "cat") + f"
{i}", "vector": [float(i), 0.0]} for i in range(40)])
t.create_index("text", config=FTS())
len(t.search(query_type="hybrid").vector([0.0,
0.0]).text("dog").to_arrow())
# before: 20, after: 10
For the same reason, `.offset(n)` without `.limit()` did not raise the
sub-query limits to cover the skipped prefix; that only happened inside
`if self._limit:`.
## Changes
- Use `DEFAULT_HYBRID_LIMIT` when no limit is set, both for the
sub-query limits (`limit + offset`) and for the final slice of the
reranked results, matching `AsyncHybridQuery`.
## Test plan
- [x] New `test_hybrid_query_default_limit` in `test_hybrid_query.py`.
It is the sync counterpart of `test_async_hybrid_query_default_limit`,
plus an `offset()`-without-`limit()` check. It fails before the fix (20
rows) and passes after.
- [x] `pytest python/tests/test_hybrid_query.py
python/tests/test_rerankers.py`
- [x] `ruff format --check` / `ruff check`
I have no local Rust toolchain, so I ran the tests against the released
0.39.0 native module with the changed Python files overlaid. The changed
functions are identical between 0.39.0 and main.