fix(chroma): reject async chroma clients with a clear error

libs/partners/chroma/langchain_chroma/vectorstores.py

@@ -6,6 +6,7 @@
 from __future__ import annotations
 
 import base64
+import inspect
 import logging
 import uuid
 from collections.abc import Callable, Iterable, Sequence
@@ -367,6 +368,15 @@ def __init__(
             raise ValueError(msg)
 
         if client is not None:
+            if inspect.isawaitable(client):
+                msg = (
+                    "`client` must be a synchronous Chroma client implementing "
+                    "`chromadb.ClientAPI`. Got an awaitable instead, which usually "
+                    "means `chromadb.AsyncHttpClient(...)` was passed in. Use "
+                    "`chromadb.HttpClient(...)` or another synchronous client "
+                    "instance instead."
+                )
+                raise TypeError(msg)
             self._client = client
 
         # PersistentClient

libs/partners/chroma/tests/unit_tests/test_vectorstores.py

@@ -1,3 +1,5 @@
+import chromadb
+import pytest
 from langchain_core.embeddings.fake import (
     FakeEmbeddings,
 )
@@ -28,3 +30,13 @@ def test_similarity_search() -> None:
     output = docsearch.similarity_search("foo", k=1)
     docsearch.delete_collection()
     assert len(output) == 1
+
+
+def test_async_http_client_rejected() -> None:
+    """Chroma should fail fast when given an async Chroma client."""
+    client = chromadb.AsyncHttpClient(host="localhost", port=8000)
+
+    with pytest.raises(TypeError, match="must be a synchronous Chroma client"):
+        Chroma(client=client)
+
+    client.close()