From c406aede962ccdb4d21621963b698e35f27fdc18 Mon Sep 17 00:00:00 2001
From: Nuno Campos <nuno@langchain.dev>
Date: Fri, 27 Jun 2025 08:57:35 -0700
Subject: [PATCH] Fix deadlock in SqliteStore

- If setup wasnt called separately _cursor() and setup() would deadlock
- The call to setup() in _cursor() should be outside the lock block, as setup() also acquires the lock and re-checks the setup flag
---
 libs/checkpoint-sqlite/langgraph/store/sqlite/aio.py  | 5 ++---
 libs/checkpoint-sqlite/langgraph/store/sqlite/base.py | 9 ++++-----
 2 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/libs/checkpoint-sqlite/langgraph/store/sqlite/aio.py b/libs/checkpoint-sqlite/langgraph/store/sqlite/aio.py
index 3b19e512d..6be00813b 100644
--- a/libs/checkpoint-sqlite/langgraph/store/sqlite/aio.py
+++ b/libs/checkpoint-sqlite/langgraph/store/sqlite/aio.py
@@ -223,10 +223,9 @@ class AsyncSqliteStore(AsyncBatchedBaseStore, BaseSqliteStore):
         Yields:
             An SQLite cursor object.
         """
+        if not self.is_setup:
+            await self.setup()
         async with self.lock:
-            if not self.is_setup:
-                await self.setup()
-
             if transaction:
                 await self.conn.execute("BEGIN")
 
diff --git a/libs/checkpoint-sqlite/langgraph/store/sqlite/base.py b/libs/checkpoint-sqlite/langgraph/store/sqlite/base.py
index 5ac1ee0e0..db161d667 100644
--- a/libs/checkpoint-sqlite/langgraph/store/sqlite/base.py
+++ b/libs/checkpoint-sqlite/langgraph/store/sqlite/base.py
@@ -981,10 +981,9 @@ class SqliteStore(BaseSqliteStore, BaseStore):
         Args:
             transaction (bool): whether to use transaction for the DB operations
         """
+        if not self.is_setup:
+            self.setup()
         with self.lock:
-            if not self.is_setup:
-                self.setup()
-
             if transaction:
                 self.conn.execute("BEGIN")
 
@@ -1002,10 +1001,10 @@ class SqliteStore(BaseSqliteStore, BaseStore):
         This method creates the necessary tables in the SQLite database if they don't
         already exist and runs database migrations. It should be called before first use.
         """
-        if self.is_setup:
-            return
 
         with self.lock:
+            if self.is_setup:
+                return
             # Create migrations table if it doesn't exist
             self.conn.executescript(
                 """