[1.2.2] P2P: Reset sync on rejected block #1726
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greg7mdp
approved these changes
Jul 14, 2025
| { | ||
| // reset sync on rejected block | ||
| fc::lock_guard g( sync_mtx ); | ||
| if (sync_last_requested_num != 0 && blk_num <= sync_next_expected_num-1) { // no need to reset if we already reset and are syncing again |
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it is not clear to me why this check indicates that we already reset?
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Say you are syncing and blocks 50-100.
- Block 65 is rejected.
- Reset
sync_last_requested_num = 0 sync_next_expected_num = 60// something less <= 65 since set to LIB+1
- Reset
- Block 66 is rejected because 65 just was and 66 can't link to anything
- 66 <= 59 is not true, so don't reset
- Same for 67-100.
spoonincode
approved these changes
Jul 15, 2025
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Reverts #1676. A recent test failure #1716 demonstrates the need for the reset. The test failed because it timed out waiting for LIB to advance. The node did actually advance LIB but not in the expected 30 second timeout. The issue was that an unlinkable block at transition from LIB catchup to HEAD catchup didn't reset sync and therefore the node didn't know it needed to continue syncing. The handshake was not sufficient because the other node thought it had caught up. This was exasperated by the node syncing was in IRREVERSIBLE mode. It is possible that we could live with only resetting when running in IRREVERSIBLE mode. However, I think the safest and most direct approach is to go back to resetting the sync, but guard against resetting the sync when know we have already reset the sync. Therefore, fixing #1673 in a different way.
Resolves #1716
Resolves #1673