fix(driver): fix a potential error which will happen when restarting a node

driver/chain_syncer.go

@@ -178,8 +178,16 @@ func (s *L2ChainSyncer) AheadOfProtocolVerifiedHead() bool {
 		// NewPayloadV1.
 		verifiedHeightToCompare -= 1
 	}
-	return (s.state.GetL2Head().Number.Uint64() >= verifiedHeightToCompare) &&
-		(s.state.GetL2Head().Number.Uint64() >= s.syncProgressTracker.LastSyncedVerifiedBlockHeight().Uint64())
+
+	if s.state.GetL2Head().Number.Uint64() < verifiedHeightToCompare {
+		return false
+	}
+
+	if s.syncProgressTracker.LastSyncedVerifiedBlockHeight() != nil {
+		return s.state.GetL2Head().Number.Uint64() >= s.syncProgressTracker.LastSyncedVerifiedBlockHeight().Uint64()
+	}
+
+	return true
 }
 
 // ProcessL1Blocks fetches all `TaikoL1.BlockProposed` events between given

driver/sync_progress_tracker.go

@@ -191,6 +191,10 @@ func (s *BeaconSyncProgressTracker) LastSyncedVerifiedBlockID() *big.Int {
 	s.mutex.RLock()
 	defer s.mutex.RUnlock()
 
+	if s.lastSyncedVerifiedBlockID == nil {
+		return nil
+	}
+
 	return new(big.Int).Set(s.lastSyncedVerifiedBlockID)
 }
 
@@ -199,6 +203,10 @@ func (s *BeaconSyncProgressTracker) LastSyncedVerifiedBlockHeight() *big.Int {
 	s.mutex.RLock()
 	defer s.mutex.RUnlock()
 
+	if s.lastSyncedVerifiedBlockHeight == nil {
+		return nil
+	}
+
 	return new(big.Int).Set(s.lastSyncedVerifiedBlockHeight)
 }