fix: Unwrap Required/NotRequired special forms before resolving channel/reducer annotations (#6080)

libs/langgraph/langgraph/graph/state.py

@@ -25,7 +25,7 @@ from typing import (
 
 from langchain_core.runnables import Runnable, RunnableConfig
 from pydantic import BaseModel, TypeAdapter
-from typing_extensions import Self, Unpack, is_typeddict
+from typing_extensions import NotRequired, Required, Self, Unpack, is_typeddict
 
 from langgraph._internal._constants import (
     INTERRUPT,
@@ -1334,6 +1334,12 @@ def _get_channel(
 def _get_channel(
     name: str, annotation: Any, *, allow_managed: bool = True
 ) -> BaseChannel | ManagedValueSpec:
+    # Strip out Required and NotRequired wrappers
+    if hasattr(annotation, "__origin__") and annotation.__origin__ in (
+        Required,
+        NotRequired,
+    ):
+        annotation = annotation.__args__[0]
     if manager := _is_field_managed_value(name, annotation):
         if allow_managed:
             return manager

libs/langgraph/tests/test_state.py

@@ -10,6 +10,7 @@ from langchain_core.runnables import RunnableConfig
 from pydantic import BaseModel
 from typing_extensions import NotRequired, Required, TypedDict
 
+from langgraph.channels.binop import BinaryOperatorAggregate
 from langgraph.graph.state import StateGraph, _get_node_name, _warn_invalid_state_schema
 
 
@@ -137,7 +138,7 @@ def test_state_schema_optional_values(total_: bool):
     class InputState(SomeParentState, total=total_):  # type: ignore
         val1: str
         val2: Optional[str]
-        val3: Required[str]
+        val3: Required[Annotated[dict, operator.or_]]
         val4: NotRequired[dict]
         val5: Annotated[Required[str], "foo"]
         val6: Annotated[NotRequired[str], "bar"]
@@ -159,6 +160,8 @@ def test_state_schema_optional_values(total_: bool):
     graph = builder.compile()
     json_schema = graph.get_input_jsonschema()
 
+    assert isinstance(graph.channels["val3"], BinaryOperatorAggregate)
+
     if total_ is False:
         expected_required = set()
         expected_optional = {"val2", "val1"}