fix(rust_brain): preserve HLC on snapshot restore and gossip replay - #72
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v0.6.0 added HybridLogicalClock enforcement but restore_from_file(), bulk_write(), and gossip.receive() did not round-trip HLC timestamps. After disaster-recovery restore, nodes received fresh HLC values, causing TimestampRegression on valid causal successor writes and silent rejection of gossiped updates. - Add _parse_hlc() for snapshot/wire normalisation with legacy fallback - restore_from_file: restore hlc, update global clock, hold lock - bulk_write: pass hlc from row payloads - gossip.receive: apply hlc, reject stale overwrites, skip missing-hlc updates - Add regression tests for restore round-trip and gossip ordering Co-authored-by: Daniel <DJLougen@users.noreply.github.com>
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Bug and impact
v0.6.0 added Hybrid Logical Clock (HLC) monotonic enforcement, but
restore_from_file(),bulk_write(), andgossip.receive()did not round-trip HLC timestamps. After disaster-recovery restore, restored nodes received fresh HLC values instead of the snapshot values. Valid causal successor writes and gossiped updates were then rejected withTimestampRegression— silent data loss in production failover scenarios.Concrete trigger: Snapshot a node with
hlc=(5000, 10, "nodeA"), restore, then attemptremember("k", "v2", hlc=(5000, 11, "nodeA"))— raisesTimestampRegressionbecause restore assigned a fresh wall-clock HLC.Root cause
restore_from_file()createdMemoryNodewithout passinghlc, so the dataclass default factory generated a new timestamp.bulk_write()andgossip.receive()similarly omitted HLC passthrough.Fix and validation
_parse_hlc()for snapshot/wire normalisation with legacy fallbackrestore_from_file: restore HLC, update global clock, hold lock during mutationbulk_write: pass HLC from row payloadsgossip.receive: apply HLC, reject stale overwrites, skip missing-HLC updates on existing keystests/test_hlc_snapshot_gossip.pyValidation: 29 targeted tests passed (
test_hlc_snapshot_gossip.py,test_enterprise_backup.py,test_gossip.py,test_rust_brain.py).