fix(rust_brain): preserve HLC on snapshot restore and gossip receive#24
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restore_from_file dropped hlc fields added in v0.6.0, assigning fresh timestamps on restore. Post-crash causal writes and gossip replays with pre-crash HLC were rejected (silent data loss), while gossip events without HLC could overwrite fresher data. - Add _parse_hlc() for snapshot/wire normalisation with legacy fallback - restore_from_file: restore hlc and advance global _hlc per node - bulk_write: pass through hlc from row payloads - gossip.receive: apply hlc, reject stale updates, skip missing-hlc overwrites on existing keys - Tests: snapshot HLC round-trip, gossip stale/new/missing-hlc cases Co-authored-by: Daniel <DJLougen@users.noreply.github.com>
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Bug and impact
Critical data-loss bug in disaster recovery and distributed sync.
restore_from_file()dropped Hybrid Logical Clock (HLC) timestamps added in v0.6.0. After a snapshot restore, nodes received fresh HLCs instead of their original causal timestamps. Any post-crash replication, gossip replay, or bulk write carrying pre-crash HLC values was rejected by monotonic enforcement — silent data loss.Separately,
gossip.receive()ignored HLC entirely: stale gossip events without timestamps could overwrite fresher local data.Concrete trigger: Node A writes
key=foowithhlc=(5000, 10, "nodeA"), snapshots, crashes, restores. Peer B replays the write with the original HLC →TimestampRegression→ write dropped.Root cause
v0.6.0 added HLC to
MemoryNodeand monotonic enforcement inremember(), butrestore_from_file()andgossip.receive()were not updated to preserve/apply HLC fields.Fix
_parse_hlc()for snapshot/wire normalisation with legacy fallback for pre-v0.6.0 snapshotsrestore_from_file: restorehlcper node and advance global_hlcbulk_write: pass throughhlcfrom row payloadsgossip.receive: applyhlc, reject stale updates, skip missing-hlc overwrites on existing keysValidation