feat(python): check vector query is not None (#1847)

Fix the type hints of `nearest_to` method, and raise `ValueError` when
the input is None

python/python/lancedb/query.py

@@ -1495,7 +1495,8 @@ class AsyncQuery(AsyncQueryBase):
         return pa.array(vec)
 
     def nearest_to(
-        self, query_vector: Optional[Union[VEC, Tuple, List[VEC]]] = None
+        self,
+        query_vector: Union[VEC, Tuple, List[VEC]],
     ) -> AsyncVectorQuery:
         """
         Find the nearest vectors to the given query vector.
@@ -1542,6 +1543,9 @@ class AsyncQuery(AsyncQueryBase):
         will be added to the results.  This column will contain the index of the
         query vector that the result is nearest to.
         """
+        if query_vector is None:
+            raise ValueError("query_vector can not be None")
+
         if (
             isinstance(query_vector, list)
             and len(query_vector) > 0
@@ -1618,7 +1622,7 @@ class AsyncVectorQuery(AsyncQueryBase):
         """
         Set the number of partitions to search (probe)
 
-        This argument is only used when the vector column has an IVF PQ index.
+        This argument is only used when the vector column has an IVF-based index.
         If there is no index then this value is ignored.
 
         The IVF stage of IVF PQ divides the input into partitions (clusters) of

python/python/lancedb/table.py

@@ -2697,7 +2697,7 @@ class AsyncTable:
 
     def vector_search(
         self,
-        query_vector: Optional[Union[VEC, Tuple]] = None,
+        query_vector: Union[VEC, Tuple],
     ) -> AsyncVectorQuery:
         """
         Search the table with a given query vector.

python/python/tests/test_query.py

@@ -1,15 +1,5 @@
-#  Copyright 2023 LanceDB Developers
-#
-#  Licensed under the Apache License, Version 2.0 (the "License");
-#  you may not use this file except in compliance with the License.
-#  You may obtain a copy of the License at
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-#  Unless required by applicable law or agreed to in writing, software
-#  distributed under the License is distributed on an "AS IS" BASIS,
-#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-#  See the License for the specific language governing permissions and
-#  limitations under the License.
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright The LanceDB Authors
 
 import unittest.mock as mock
 from datetime import timedelta
@@ -342,6 +332,12 @@ async def test_query_to_pandas_async(table_async: AsyncTable):
     assert df.shape == (0, 4)
 
 
+@pytest.mark.asyncio
+async def test_none_query(table_async: AsyncTable):
+    with pytest.raises(ValueError):
+        await table_async.query().nearest_to(None).to_arrow()
+
+
 @pytest.mark.asyncio
 async def test_fast_search_async(tmp_path):
     db = await lancedb.connect_async(tmp_path)