INPYTHON-764 Make usage of text_key more obvious

Author: blink1073

libs/langchain-mongodb/langchain_mongodb/vectorstores.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import logging
+import warnings
 from typing import (
     Any,
     Callable,
@@ -108,6 +109,7 @@ class MongoDBAtlasVectorSearch(VectorStore):
                 namespace="db_name.collection_name",
                 embedding=OpenAIEmbeddings(),
                 index_name="vector_index",
+                text_key="text_field"
             )
 
     Add Documents:
@@ -807,15 +809,27 @@ def _similarity_search_with_score(
         docs = []
 
         # Format
+        missing_text_key = False
         for res in cursor:
             if self._text_key not in res:
+                missing_text_key = True
                 continue
             text = res.pop(self._text_key)
             score = res.pop("score")
             make_serializable(res)
             docs.append(
                 (Document(page_content=text, metadata=res, id=res["_id"]), score)
             )
+
+        if (
+            missing_text_key
+            and not len(docs)
+            and self._collection.count_documents({}) > 0
+        ):
+            warnings.warn(
+                f"Could not find any documents with the text_key: '{self._text_key}'",
+                stacklevel=2,
+            )
         return docs
 
     def create_vector_search_index(

libs/langchain-mongodb/pyproject.toml

@@ -45,13 +45,20 @@ dev = [
 ]
 
 [tool.pytest.ini_options]
+minversion = "7"
 addopts = "--snapshot-warn-unused --strict-markers --strict-config --durations=5"
+log_cli_level = "INFO"
+faulthandler_timeout = 1500
+xfail_strict = true
 markers = [
     "requires: mark tests as requiring a specific library",
     "compile: mark placeholder test used to compile integration tests without running them",
 ]
 asyncio_mode = "auto"
 asyncio_default_fixture_loop_scope = "function"
+filterwarnings = [
+    "error"
+]
 
 [tool.mypy]
 disallow_untyped_defs = true

libs/langchain-mongodb/tests/integration_tests/test_vectorstore_add_delete.py

@@ -12,6 +12,9 @@
 from pymongo.collection import Collection
 
 from langchain_mongodb import MongoDBAtlasVectorSearch
+from langchain_mongodb.index import (
+    create_vector_search_index,
+)
 from langchain_mongodb.utils import oid_to_str
 
 from ..utils import DB_NAME, ConsistentFakeEmbeddings, PatchedMongoDBAtlasVectorSearch
@@ -23,9 +26,24 @@
 
 @pytest.fixture
 def collection(client: MongoClient) -> Collection:
-    clx = client[DB_NAME][COLLECTION_NAME]
-    clx.delete_many({})
-    return clx
+    if COLLECTION_NAME not in client[DB_NAME].list_collection_names():
+        clxn = client[DB_NAME].create_collection(COLLECTION_NAME)
+    else:
+        clxn = client[DB_NAME][COLLECTION_NAME]
+
+    clxn.delete_many({})
+
+    if not any([INDEX_NAME == ix["name"] for ix in clxn.list_search_indexes()]):
+        create_vector_search_index(
+            collection=clxn,
+            index_name=INDEX_NAME,
+            dimensions=DIMENSIONS,
+            path="embedding",
+            similarity="cosine",
+            wait_until_complete=60,
+        )
+
+    return clxn
 
 
 @pytest.fixture(scope="module")
@@ -206,3 +224,34 @@ def test_add_documents(
     result_ids = vectorstore.add_documents(docs, ids, batch_size=batch_size)
     assert len(result_ids) == n_docs
     assert set(ids) == set(collection.distinct("_id"))
+
+
+def test_warning_for_misaligned_text_key(
+    collection: Collection, trivial_embeddings: Embeddings
+):
+    collection.delete_many({})
+    vectorstore = PatchedMongoDBAtlasVectorSearch(
+        collection=collection,
+        embedding=trivial_embeddings,
+        index_name=INDEX_NAME,
+    )
+
+    # If the collection is empty, no warning is raised.
+    assert len(vectorstore.similarity_search("foo")) == 0
+
+    # Insert a document that doesn't match the text key, and look for the warning.
+    collection.delete_many({})
+    vectorstore.add_texts(["foo"], ids=["1"])
+    # Update the doc to change the text field to a different one.
+    collection.update_one(
+        {"_id": "1"},
+        {"$unset": {vectorstore._text_key: ""}, "$set": {"fake_text_key": "foo"}},
+    )
+    with pytest.warns(UserWarning) as record:
+        vectorstore.similarity_search("foo")
+
+    assert len(record) == 1
+    assert (
+        record[0].message.args[0]
+        == "Could not find any documents with the text_key: 'text'"
+    )