From c9d5d5b3175e3b5a21c5b08d5c067ab6ff1f53af Mon Sep 17 00:00:00 2001
From: Elior Nataf Lackritz <elior.nataflackritz@langchain.dev>
Date: Mon, 28 Sep 2026 16:30:32 -0400
Subject: [PATCH] refactor(langgraph): make _prepare_state_snapshot recurse a
 bool

recurse only ever carried the same saver as saver, or None. Take a flag and
hand saver to the child's CONFIG_KEY_CHECKPOINTER, so the snapshot helpers
hold the saver in one argument.
---
 libs/langgraph/langgraph/pregel/main.py | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/libs/langgraph/langgraph/pregel/main.py b/libs/langgraph/langgraph/pregel/main.py
index c96a46b61..39a196d42 100644
--- a/libs/langgraph/langgraph/pregel/main.py
+++ b/libs/langgraph/langgraph/pregel/main.py
@@ -1148,7 +1148,7 @@ class Pregel(
         saved: CheckpointTuple | None,
         *,
         saver: BaseCheckpointSaver,
-        recurse: BaseCheckpointSaver | None = None,
+        recurse: bool = False,
         apply_pending_writes: bool = False,
     ) -> StateSnapshot:
         if not saved:
@@ -1213,7 +1213,7 @@ class Pregel(
                 # get the state of the subgraph
                 config = {
                     CONF: {
-                        CONFIG_KEY_CHECKPOINTER: recurse,
+                        CONFIG_KEY_CHECKPOINTER: saver,
                         "thread_id": saved.config[CONF]["thread_id"],
                         CONFIG_KEY_CHECKPOINT_NS: task_ns,
                     }
@@ -1267,7 +1267,7 @@ class Pregel(
         saved: CheckpointTuple | None,
         *,
         saver: BaseCheckpointSaver,
-        recurse: BaseCheckpointSaver | None = None,
+        recurse: bool = False,
         apply_pending_writes: bool = False,
     ) -> StateSnapshot:
         if not saved:
@@ -1332,7 +1332,7 @@ class Pregel(
                 # get the state of the subgraph
                 config = {
                     CONF: {
-                        CONFIG_KEY_CHECKPOINTER: recurse,
+                        CONFIG_KEY_CHECKPOINTER: saver,
                         "thread_id": saved.config[CONF]["thread_id"],
                         CONFIG_KEY_CHECKPOINT_NS: task_ns,
                     }
@@ -1422,7 +1422,7 @@ class Pregel(
             config,
             saved,
             saver=checkpointer,
-            recurse=checkpointer if subgraphs else None,
+            recurse=subgraphs,
             apply_pending_writes=CONFIG_KEY_CHECKPOINT_ID not in config[CONF],
         )
 
@@ -1467,7 +1467,7 @@ class Pregel(
             config,
             saved,
             saver=checkpointer,
-            recurse=checkpointer if subgraphs else None,
+            recurse=subgraphs,
             apply_pending_writes=CONFIG_KEY_CHECKPOINT_ID not in config[CONF],
         )