Ensure config defaults apply even when a config is passed in

libs/langchain/langchain/schema/runnable/base.py

@@ -35,8 +35,11 @@ from langchain.schema.runnable.utils import (
 from langchain.utils.aiter import atee, py_anext
 
 
-def _empty_config() -> RunnableConfig:
-    return RunnableConfig(tags=[], metadata={}, callbacks=None, _locals={})
+def _ensure_config(config: Optional[RunnableConfig]) -> RunnableConfig:
+    empty = RunnableConfig(tags=[], metadata={}, callbacks=None, _locals={})
+    if config is not None:
+        empty.update(config)
+    return empty
 
 
 def _get_callback_manager(config: Mapping) -> Any:
@@ -238,10 +241,7 @@ class Runnable(Generic[Input, Output], ABC):
         return (
             config
             if isinstance(config, list)
-            else [
-                deepcopy(config) if config is not None else _empty_config()
-                for _ in range(length)
-            ]
+            else [deepcopy(_ensure_config(config)) for _ in range(length)]
         )
 
     def _call_with_config(
@@ -253,7 +253,7 @@ class Runnable(Generic[Input, Output], ABC):
     ) -> Output:
         """Helper method to transform an Input value to an Output value,
         with callbacks. Use this method to implement invoke() in subclasses."""
-        config = config or _empty_config()
+        config = _ensure_config(config)
         callback_manager = _get_callback_manager(config)
         run_manager = callback_manager.on_chain_start(
             dumpd(self),
@@ -283,7 +283,7 @@ class Runnable(Generic[Input, Output], ABC):
     ) -> Output:
         """Helper method to transform an Input value to an Output value,
         with callbacks. Use this method to implement ainvoke() in subclasses."""
-        config = config or _empty_config()
+        config = _ensure_config(config)
         callback_manager = _get_async_callback_manager(config)
         run_manager = await callback_manager.on_chain_start(
             dumpd(self),
@@ -322,7 +322,7 @@ class Runnable(Generic[Input, Output], ABC):
         final_output: Optional[Output] = None
         final_output_supported = True
 
-        config = config or _empty_config()
+        config = _ensure_config(config)
         callback_manager = _get_callback_manager(config)
         run_manager = callback_manager.on_chain_start(
             dumpd(self),
@@ -387,7 +387,7 @@ class Runnable(Generic[Input, Output], ABC):
         final_output: Optional[Output] = None
         final_output_supported = True
 
-        config = config or _empty_config()
+        config = _ensure_config(config)
         callback_manager = _get_async_callback_manager(config)
         run_manager = await callback_manager.on_chain_start(
             dumpd(self),
@@ -462,7 +462,7 @@ class RunnableWithFallbacks(Serializable, Runnable[Input, Output]):
 
     def invoke(self, input: Input, config: Optional[RunnableConfig] = None) -> Output:
         # setup callbacks
-        config = config or _empty_config()
+        config = _ensure_config(config)
         callback_manager = _get_callback_manager(config)
         # start the root run
         run_manager = callback_manager.on_chain_start(
@@ -495,7 +495,7 @@ class RunnableWithFallbacks(Serializable, Runnable[Input, Output]):
         self, input: Input, config: Optional[RunnableConfig] = None
     ) -> Output:
         # setup callbacks
-        config = config or _empty_config()
+        config = _ensure_config(config)
         callback_manager = _get_async_callback_manager(config)
         # start the root run
         run_manager = await callback_manager.on_chain_start(
@@ -724,7 +724,7 @@ class RunnableSequence(Serializable, Runnable[Input, Output]):
 
     def invoke(self, input: Input, config: Optional[RunnableConfig] = None) -> Output:
         # setup callbacks
-        config = config or _empty_config()
+        config = _ensure_config(config)
         callback_manager = _get_callback_manager(config)
         # start the root run
         run_manager = callback_manager.on_chain_start(
@@ -753,7 +753,7 @@ class RunnableSequence(Serializable, Runnable[Input, Output]):
         self, input: Input, config: Optional[RunnableConfig] = None
     ) -> Output:
         # setup callbacks
-        config = config or _empty_config()
+        config = _ensure_config(config)
         callback_manager = _get_async_callback_manager(config)
         # start the root run
         run_manager = await callback_manager.on_chain_start(
@@ -899,7 +899,7 @@ class RunnableSequence(Serializable, Runnable[Input, Output]):
         self, input: Input, config: Optional[RunnableConfig] = None
     ) -> Iterator[Output]:
         # setup callbacks
-        config = config or _empty_config()
+        config = _ensure_config(config)
         callback_manager = _get_callback_manager(config)
         # start the root run
         run_manager = callback_manager.on_chain_start(
@@ -966,7 +966,7 @@ class RunnableSequence(Serializable, Runnable[Input, Output]):
         self, input: Input, config: Optional[RunnableConfig] = None
     ) -> AsyncIterator[Output]:
         # setup callbacks
-        config = config or _empty_config()
+        config = _ensure_config(config)
         callback_manager = _get_async_callback_manager(config)
         # start the root run
         run_manager = await callback_manager.on_chain_start(
@@ -1068,7 +1068,7 @@ class RunnableMap(Serializable, Runnable[Input, Dict[str, Any]]):
         from langchain.callbacks.manager import CallbackManager
 
         # setup callbacks
-        config = config or _empty_config()
+        config = _ensure_config(config)
         callback_manager = CallbackManager.configure(
             inheritable_callbacks=config.get("callbacks"),
             local_callbacks=None,
@@ -1108,7 +1108,7 @@ class RunnableMap(Serializable, Runnable[Input, Dict[str, Any]]):
         self, input: Input, config: Optional[RunnableConfig] = None
     ) -> Dict[str, Any]:
         # setup callbacks
-        config = config or _empty_config()
+        config = _ensure_config(config)
         callback_manager = _get_async_callback_manager(config)
         # start the root run
         run_manager = await callback_manager.on_chain_start(

libs/langchain/tests/unit_tests/schema/runnable/test_runnable.py

@@ -134,8 +134,12 @@ async def test_default_method_implementations(mocker: MockerFixture) -> None:
 
     assert fake.batch(["hello", "wooorld"], dict(tags=["a-tag"])) == [5, 7]
     assert spy.call_args_list == [
-        mocker.call("hello", dict(tags=["a-tag"])),
-        mocker.call("wooorld", dict(tags=["a-tag"])),
+        mocker.call(
+            "hello", dict(tags=["a-tag"], metadata={}, callbacks=None, _locals={})
+        ),
+        mocker.call(
+            "wooorld", dict(tags=["a-tag"], metadata={}, callbacks=None, _locals={})
+        ),
     ]
     spy.reset_mock()
 
@@ -156,8 +160,14 @@ async def test_default_method_implementations(mocker: MockerFixture) -> None:
         7,
     ]
     assert spy.call_args_list == [
-        mocker.call("hello", dict(metadata={"key": "value"})),
-        mocker.call("wooorld", dict(metadata={"key": "value"})),
+        mocker.call(
+            "hello",
+            dict(metadata={"key": "value"}, tags=[], callbacks=None, _locals={}),
+        ),
+        mocker.call(
+            "wooorld",
+            dict(metadata={"key": "value"}, tags=[], callbacks=None, _locals={}),
+        ),
     ]