Use import-time is_new_best for newHeads notifications
#1781
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…ions
Fix a race condition where intermediate blocks during reorgs were not
being notified to eth_subscribe("newHeads") subscribers.
The issue was that MappingSyncWorker determined is_new_best by querying
client.info().best_hash at sync time, not at import time. During rapid
reorgs, the best hash could change between import and sync, causing
intermediate blocks to incorrectly have is_new_best=false and be
filtered out by EthPubSub.
Changes:
- Add best_at_import HashSet to track blocks that were is_new_best
at the time of their BlockImportNotification
- Capture notification.is_new_best from import notifications
- Use import-time status when available, fall back to current best
hash check for blocks synced during catch-up
This was referenced Dec 3, 2025
librelois
reviewed
Dec 3, 2025
librelois
requested changes
Dec 3, 2025
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librelois
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librelois
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It sees that the new HashSet best_at_import is not properly pruned, this imply potential infinite growth.
Can you rethink the implementation to make sure the list best_at_import is bounded and properly pruned?
librelois
approved these changes
Dec 3, 2025
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Description
Fixes a race condition where intermediate blocks during reorgs were not being notified to
eth_subscribe("newHeads")subscribers (issue reported on Moonbeam).The issue was that
MappingSyncWorkerdeterminedis_new_bestby queryingclient.info().best_hashat sync time, not at import time. During rapid reorgs, the best hash could change between import and sync, causing intermediate blocks to incorrectly haveis_new_best=falseand be filtered out byEthPubSub.Changes:
best_at_importHashSetto track blocks that wereis_new_bestat the time of theirBlockImportNotificationnotification.is_new_bestfrom import notifications