Files
langgraph/libs/checkpoint-postgres/tests
1ba96f49bf fix(checkpoint): handle metadata.writes when serializing old checkpoints with Jsonb (#6236)
Issue

Support for `Checkpoint.metadata.writes` was dropped in `langgraph`
v0.5.x.

In `langgraph-checkpoint-postgres` v2.0.23, metadata was serialized with
`BasePostgresSaver._dump_metadata` -> `JsonPlusSerializer.dumps` which
handles `pydantic.BaseModel`.

In v2.0.23, metadata is serialized with `psycopg.types.json.Jsonb`,
which raises `TypeError: Object of type AIMessage is not JSON
serializable` when trying to serialize `writes`.

Solution

- Add `BaseCheckpointSaver.get_serializable_checkpoint_metadata` which
pops the `writes` key.
- Log deprecation warning when strange version combinations are used 

Solves https://github.com/langchain-ai/langgraph/issues/5769

---------

Co-authored-by: Alex Kondratev <56111142+soapun@users.noreply.github.com>
2025-10-06 11:27:34 -07:00
..
2024-11-28 04:40:12 +00:00