fix(rust_brain): preserve HLC on snapshot restore and gossip receive#45
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restore_from_file() assigned fresh HLC timestamps instead of reading the values embedded in snapshots. After disaster recovery, any write with the pre-crash causal order was rejected with TimestampRegression, causing silent data loss on replication and gossip replay. - Add _parse_hlc() for snapshot/wire normalisation - Restore HLC and advance global clock on snapshot restore - Pass HLC through bulk_write and gossip.receive() - Reject stale gossip overwrites; skip missing-HLC updates on existing keys - Lock gc_expired and restore mutations for thread safety Co-authored-by: Daniel <DJLougen@users.noreply.github.com>
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Bug and impact
restore_from_file()andgossip.receive()did not preserve or apply Hybrid Logical Clock (HLC) timestamps introduced in v0.6.0. After disaster recovery or cross-node gossip, restored nodes received fresh HLC values instead of their original causal timestamps.Concrete trigger: Write a node with
hlc=(5000, 10, "nodeA"), snapshot, restore, then attempt a causal successor write withhlc=(5000, 11, "nodeA"). The write raisesTimestampRegressionand is silently dropped — causing data loss on replication and gossip replay.Root cause
restore_from_file()constructedMemoryNodewithout readinghlcfrom the snapshot dict, so each restored node got a fresh wall-clock HLC.gossip.receive()calledremember()without passinghlcfrom gossip events.bulk_write()also omitted HLC passthrough.Fix
_parse_hlc()to normalise HLC from snapshot/wire form (list/tuple) with legacy fallback._hlc.update().bulk_write()andgossip.receive()with stale-overwrite rejection.gc_expired()and restore mutations for thread safety.Validation