add deprecation warning for no overall state (#1698)

* deprecation warning for no overall state

* lance comments

docs/docs/how-tos/input_output_schema.ipynb

@@ -7,7 +7,7 @@
    "source": [
     "# How to define input/output schema for your graph\n",
     "\n",
-    "By default, `StateGraph` takes in a single schema and all nodes are expected to communicate with that schema. However, it is also possible to define explicit input and output schemas for a graph. This is helpful if you want to draw a distinction between input and output keys.\n",
+    "By default, `StateGraph` takes in a single schema and all nodes are expected to communicate with that schema. However, it is also possible to define explicit input and output schemas for a graph. Often, in these cases, we define an \"internal\" schema that contains all keys relevant to graph operations. But, we use specific input and output schemas to filter what's permitted when invoking and what's returned. We use type hints below to, for example, show that the output of `answer_node` will be filtered to `OutputState`. In addition, we define each node's input schema (e.g., as state: `OverallState` for `answer_node`).\n",
     "\n",
     "In this notebook we'll walk through an example of this. At a high level, in order to do this you simply have to pass in `input=..., output=...` when defining the graph. Let's see an example below!\n",
     "\n",
@@ -50,7 +50,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 12,
+   "execution_count": 5,
    "id": "6ec0eb77-874e-443e-8c73-93125b515106",
    "metadata": {},
    "outputs": [
@@ -60,7 +60,7 @@
        "{'answer': 'bye'}"
       ]
      },
-     "execution_count": 12,
+     "execution_count": 5,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -77,16 +77,18 @@
     "class OutputState(TypedDict):\n",
     "    answer: str\n",
     "\n",
+    "class OverallState(InputState, OutputState):\n",
+    "    pass\n",
     "\n",
     "def answer_node(state: InputState):\n",
     "    return {\"answer\": \"bye\"}\n",
     "\n",
     "\n",
-    "graph = StateGraph(input=InputState, output=OutputState)\n",
-    "graph.add_node(answer_node)\n",
-    "graph.add_edge(START, \"answer_node\")\n",
-    "graph.add_edge(\"answer_node\", END)\n",
-    "graph = graph.compile()\n",
+    "builder = StateGraph(OverallState, input=InputState, output=OutputState)\n",
+    "builder.add_node(answer_node)\n",
+    "builder.add_edge(START, \"answer_node\")\n",
+    "builder.add_edge(\"answer_node\", END)\n",
+    "graph = builder.compile()\n",
     "\n",
     "graph.invoke({\"question\": \"hi\"})"
    ]
@@ -116,7 +118,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.11.1"
+   "version": "3.11.9"
   }
  },
  "nbformat": 4,