core, tests: more tolerant _aget_relevant_documents function (#28462)

libs/core/langchain_core/retrievers.py

@@ -27,7 +27,7 @@
 from typing import TYPE_CHECKING, Any, Optional
 
 from pydantic import ConfigDict
-from typing_extensions import TypedDict
+from typing_extensions import Self, TypedDict
 
 from langchain_core._api import deprecated
 from langchain_core.documents import Document
@@ -180,6 +180,18 @@ def __init_subclass__(cls, **kwargs: Any) -> None:
             cls._aget_relevant_documents = aswap  # type: ignore[assignment]
         parameters = signature(cls._get_relevant_documents).parameters
         cls._new_arg_supported = parameters.get("run_manager") is not None
+        if (
+            not cls._new_arg_supported
+            and cls._aget_relevant_documents == BaseRetriever._aget_relevant_documents
+        ):
+            # we need to tolerate no run_manager in _aget_relevant_documents signature
+            async def _aget_relevant_documents(
+                self: Self, query: str
+            ) -> list[Document]:
+                return await run_in_executor(None, self._get_relevant_documents, query)  # type: ignore
+
+            cls._aget_relevant_documents = _aget_relevant_documents  # type: ignore[assignment]
+
         # If a V1 retriever broke the interface and expects additional arguments
         cls._expects_other_args = (
             len(set(parameters.keys()) - {"self", "query", "run_manager"}) > 0

libs/standard-tests/tests/unit_tests/test_basic_retriever.py

@@ -1,6 +1,5 @@
 from typing import Any, Type
 
-from langchain_core.callbacks import CallbackManagerForRetrieverRun
 from langchain_core.documents import Document
 from langchain_core.retrievers import BaseRetriever
 
@@ -11,9 +10,7 @@ class ParrotRetriever(BaseRetriever):
     parrot_name: str
     k: int = 3
 
-    def _get_relevant_documents(
-        self, query: str, *, run_manager: CallbackManagerForRetrieverRun, **kwargs: Any
-    ) -> list[Document]:
+    def _get_relevant_documents(self, query: str, **kwargs: Any) -> list[Document]:
         k = kwargs.get("k", self.k)
         return [Document(page_content=f"{self.parrot_name} says: {query}")] * k