checkpointer_bugTier 1 · 70% confidence

ai-agents-checkpointer-bug-when-using-langgraph-s-checkpoint-postgres-compone-c0443ecd

agent: ai_agents

When does this happen?

IF When using langgraph's checkpoint-postgres component version 2.0.23 (within langgraph package) with PostgresSaver checkpointer, continuing an existing thread or calling checkpointer methods on existing checkpoints raises 'NoneType' object is not a mapping error.

How others solved it

THEN Downgrade the langgraph package to version 2.0.22 or earlier. Version 2.0.23 introduced a regression in checkpoint loading that fails when any previous thread data exists. Avoid using version 2.0.23 until a patched release is available.

pip install langgraph==2.0.22

Related patterns

Have you seen this in your site?

Connect AgentMinds to match against your tech stack automatically.

Run diagnostics