fix recursive stack overflow consensus reload

kernel/election.go

@@ -377,6 +377,10 @@ func (node *Node) reloadConsensusState(s *common.Snapshot, tx *common.VersionedT
 		common.TransactionTypeNodeRemove,
 		common.TransactionTypeCustodianUpdateNodes,
 		common.TransactionTypeCustodianSlashNodes:
+		err := node.persistStore.WriteConsensusSnapshot(s, tx)
+		if err != nil {
+			return err
+		}
 	default:
 		return nil
 	}
@@ -399,13 +403,13 @@ func (node *Node) reloadConsensusState(s *common.Snapshot, tx *common.VersionedT
 	case common.TransactionTypeNodeAccept:
 	case common.TransactionTypeNodeRemove:
 	default:
-		return node.persistStore.WriteConsensusSnapshot(s, tx)
+		return nil
 	}
 
 	signer := tx.NodeTransactionExtraAsSigner()
 	id := signer.Hash().ForNetwork(node.networkId)
 	if id == s.NodeId {
-		return node.persistStore.WriteConsensusSnapshot(s, tx)
+		return nil
 	}
 
 	chain = node.BootChain(id)
@@ -416,7 +420,7 @@ func (node *Node) reloadConsensusState(s *common.Snapshot, tx *common.VersionedT
 	if chain.ConsensusInfo == nil {
 		panic("should never be here")
 	}
-	return node.persistStore.WriteConsensusSnapshot(s, tx)
+	return nil
 }
 
 func (node *Node) finalizeNodeAcceptSnapshot(s *common.Snapshot, signers []crypto.Hash) error {

kernel/node.go

@@ -109,6 +109,11 @@ func SetupNode(custom *config.Custom, store storage.Store, cache *ristretto.Cach
 	if err != nil {
 		return nil, fmt.Errorf("LoadConsensusNodes() => %v", err)
 	}
+	s, tx := node.persistStore.LastSnapshot()
+	err = node.reloadConsensusState(s.Snapshot, tx)
+	if err != nil {
+		return nil, fmt.Errorf("reloadConsensusState(%v) => %v", s, err)
+	}
 
 	err = node.LoadAllChainsAndGraphTimestamp(node.persistStore, node.networkId)
 	if err != nil {
@@ -323,10 +328,6 @@ func (node *Node) LoadConsensusNodes() error {
 	node.allNodesSortedWithState = cnodes
 	node.nodeStateSequences = node.buildNodeStateSequences(cnodes, false)
 	node.acceptedNodeStateSequences = node.buildNodeStateSequences(cnodes, true)
-	s, tx := node.persistStore.LastSnapshot()
-	if s != nil {
-		return node.reloadConsensusState(s.Snapshot, tx)
-	}
 	return nil
 }
 

storage/badger_topology.go

@@ -120,10 +120,7 @@ func readSnapshotsSinceTopology(txn *badger.Txn, topologyOffset, count uint64) (
 	return snapshots, nil
 }
 
-func (s *BadgerStore) LastSnapshot() (*common.SnapshotWithTopologicalOrder, *common.VersionedTransaction) {
-	txn := s.snapshotsDB.NewTransaction(false)
-	defer txn.Discard()
-
+func readLastTopology(txn *badger.Txn) uint64 {
 	opts := badger.DefaultIteratorOptions
 	opts.PrefetchValues = false
 	opts.Reverse = true
@@ -132,15 +129,25 @@ func (s *BadgerStore) LastSnapshot() (*common.SnapshotWithTopologicalOrder, *com
 	defer it.Close()
 
 	it.Seek(graphTopologyKey(^uint64(0)))
-	if !it.ValidForPrefix([]byte(graphPrefixTopology)) {
-		return nil, nil
+	if it.ValidForPrefix([]byte(graphPrefixTopology)) {
+		key := it.Item().KeyCopy(nil)
+		return graphTopologyOrder(key)
 	}
-	key := it.Item().KeyCopy(nil)
-	topo := graphTopologyOrder(key)
+	return 0
+}
+
+func (s *BadgerStore) LastSnapshot() (*common.SnapshotWithTopologicalOrder, *common.VersionedTransaction) {
+	txn := s.snapshotsDB.NewTransaction(false)
+	defer txn.Discard()
+
+	topo := readLastTopology(txn)
 	snaps, err := readSnapshotsSinceTopology(txn, topo, 10)
 	if err != nil {
 		panic(err)
 	}
+	if topo == 0 && len(snaps) == 0 {
+		return nil, nil
+	}
 	if len(snaps) != 1 {
 		panic(topo)
 	}