fix(rust_brain): preserve HLC on snapshot restore and gossip receive#26
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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 v0.6.0 HLC enforcement.
After
restore_from_file(), restored nodes received fresh HLC timestamps instead of the values stored in the snapshot. Causal successor writes from the original writer (e.g. gossip replay or post-crash replication withhlc=(5000, 11, "nodeA")) were rejected as stale, causing silent data loss. Separately,gossip.receive()ignored HLC entirely, allowing gossip events without HLC to overwrite fresher local data.Concrete trigger: snapshot → restore →
remember(key, v2, hlc=successor)raisesTimestampRegressionand the update is dropped.Root cause
restore_from_file()constructedMemoryNodewithout restoring thehlcfield from snapshot JSON.gossip.receive()calledremember()without passinghlc,ts_ns, oredges.bulk_write()did not pass throughhlcfrom row payloads.Fix
_parse_hlc()for snapshot/wire normalization with legacyts_nsfallback.restore_from_file(): restorehlcper node and advance global_hlc.bulk_write(): pass throughhlcwhen present.gossip.receive(): applyhlc, reject stale updates, skip missing-HLC overwrites on existing keys.Validation
test_restore_preserves_hlc_for_replication, gossip stale/new/missing-hlc cases.