Issue evidence · Launch · langchain-ai/langgraph

update_state fails with missing checkpoint_ns when addressed by checkpoint_id

GitHub issue: https://github.com/langchain-ai/langgraph/issues/9271

Reproduced, workaround proven

Addressing a checkpoint by checkpoint_id alone makes update_state fail inside the saver.

What Badgr ran

Ran the issue's script on LangGraph 1.2.14 with an in-memory saver, then again with checkpoint_ns set to an empty string.

What came back

  • Without checkpoint_ns: KeyError: 'checkpoint_ns' in InMemorySaver.put.
  • With "checkpoint_ns": "" in the config: update_state succeeded.

Checked 2026-10-11 in Badgr’s local development environment.

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