fix(checkpointer): apply ttl to minimal checkpoint for cancellation#190
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zettlt2 wants to merge 1 commit into
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fix(checkpointer): apply ttl to minimal checkpoint for cancellation#190zettlt2 wants to merge 1 commit into
zettlt2 wants to merge 1 commit into
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Summary
This PR ensures that Time-to-Live (TTL) is applied to minimal fallback checkpoints created during cancellation or interruption events, preventing orphaned keys from persisting indefinitely in Redis when a TTL is configured.
Cause of the Issue
When AsyncRedisSaver.aput() intercepts an asyncio.CancelledError during streaming ( values or messages modes), it writes a minimal fallback checkpoint to allow later resumption. However, this fallback write path did not invoke the TTL application logic. As a result, these fallback checkpoints remained in Redis permanently, bypassing any global or thread-specific TTL policy.
Solution
• Added a call to await self._apply_ttl_to_keys(checkpoint_key) directly after saving the minimal checkpoint inside the CancelledError block in langgraph/checkpoint/redis/aio.py .
• This ensures any configured default TTL is applied to the key if configured using the existing private function.
Testing
Added a new test case test_async_ttl_applied_on_cancellation to tests/test_async_ttl_synchronization.py .