dimgigov
4791434cea
FV-2: Raft leader step-down on partition loss
...
- Add heartbeatReceived variable tracking last term with heartbeat
- Add Heartbeat action: leader sends keep-alive; recipient steps down on higher term
- Add HeartbeatTimeout: follower starts election if no heartbeat in current term
- Add LeaderLeaseExpired: leader steps down if it loses quorum connectivity
- Add LeaderHasSelfHeartbeat invariant: every leader must have valid heartbeat
- raft.tla now models realistic partition behavior (38M states verified)
- Update CHANGELOG -> v1.2.0, VERSION -> 1.2.0, PLAN.md, README.md
2026-05-07 21:48:03 +03:00
dimgigov
f9e5169c3d
FV-6: Liveness properties + fairness constraints
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- mvcc.tla: Add CommitProgress liveness (verified with WF_vars)
- raft/twopc/mvcc/gossip: Add Spec definitions with WF_vars(Next)
- gossip.tla: Fix LearnViaGossip strength-based filtering
(prevents overwriting Dead/Suspect with weaker state)
- twopc.tla: Add DecideCommitAction/DecideAbortAction for SF fairness
- Update all .cfg files to use SPECIFICATION Spec
- Update CHANGELOG.md -> v1.1.0, VERSION -> 1.1.0, PLAN.md
2026-05-07 21:21:22 +03:00
dimgigov
54711d0190
FV-1, FV-13: Raft prevLogIndex/prevLogTerm + CI fix
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- raft.tla: Add HasCompatiblePrefix check (prevLogIndex/prevLogTerm)
- raft.tla: Add RejectAppendEntries action for follower rejection
- raft.tla: Add conflict truncation + commitIndex/matchIndex adjustment
- raft.tla: Restore LogMatching invariant
- raft.tla: Guard AppendEntry to prevent term gaps in leader log
- models/raft.cfg: Add LogMatching to checked invariants
- .github/workflows/ci.yml: Replace container with setup-java + cache
- run_all.sh: Use -workers auto and -XX:+UseParallelGC
- Update PLAN.md, PLAN_DONE.md, ANALYSIS.md, README.md
2026-05-07 19:21:01 +03:00
dimgigov
19d0ff7366
feat(verify): expand formal verification to 7 specs, add versioning, CI integration
...
Added 3 new TLA+ specs:
- gossip.tla — SWIM gossip membership & failure detection
- deadlock.tla — wait-for graph deadlock detection
- sharding.tla — consistent hashing shard assignment
Improved existing 4 specs:
- raft.tla: added CommittedIndexValid invariant
- twopc.tla: added CoordinatorConsistency, NoDecideWithoutConsensus,
ParticipantStateValid; increased to MaxTxnId=3
- mvcc.tla: added CommittedMustStart, CommittedVersionsUnique
- replication.tla: added AppliedLteCurrent, SemiSyncQuorum
Infrastructure:
- VERSION file (1.0.0)
- CHANGELOG.md
- ANALYSIS.md (weak spots & improvement plan)
- run_all.sh script for batch TLC verification
- CI verify job in GitHub Actions
- Updated README with new specs and properties
Total: 7 specs, 26 invariants, 11.6M states checked, 0 errors
2026-05-07 18:26:55 +03:00
dimgigov
e73bfb450c
feat: formal verification suite — TLA+ specs for Raft, 2PC, MVCC, Replication
...
Verified with TLC model checker:
- Raft: 475k states, ElectionSafety + StateMachineSafety
- 2PC: 22k states, Atomicity + NoOrphanBlocks
- MVCC: 177k states, NoDirtyReads + ReadOwnWrites + WriteWriteConflict
- Replication: 3.6M states, MonotonicLsn + AcksRemovePending
2026-05-07 15:57:33 +03:00
dimgigov