Context

Describe the background behind the problem.

Our checkpointer does not allow one to call the kwargs of langgraph.checkpoint.serde.jsonplus.JsonPlusSerializer(). In versions < 3.0, this mean that it does not allow a fallback to pickle. In versions >= 3.0, it means one cannot also defined allowed_json_modules for safe deserialization.

Definition of done

What must be done to consider the task complete?

• Add these kwargs to the checkpoint constructor. Ensure they are used in the .utils module where serialization is performed.

Pitfalls

What should the implementer watch out for? What are the risks?
Do not want this change to slow down the fix to the CVE.