op-proposer, op-batcher: Wait for sync in Start rather than loop. (#11192)

Ensures that if it fails, the process exits with an error, rather than just exiting the runloop and continuing on in a zombie mode that doesn't do anything but doesn't exit.

op-batcher/batcher/driver.go

@@ -114,6 +114,13 @@ func (l *BatchSubmitter) StartBatchSubmitting() error {
 	l.clearState(l.shutdownCtx)
 	l.lastStoredBlock = eth.BlockID{}
 
+	if l.Config.WaitNodeSync {
+		err := l.waitNodeSync()
+		if err != nil {
+			return fmt.Errorf("error waiting for node sync: %w", err)
+		}
+	}
+
 	l.wg.Add(1)
 	go l.loop()
 
@@ -289,13 +296,6 @@ const (
 
 func (l *BatchSubmitter) loop() {
 	defer l.wg.Done()
-	if l.Config.WaitNodeSync {
-		err := l.waitNodeSync()
-		if err != nil {
-			l.Log.Error("Error waiting for node sync", "err", err)
-			return
-		}
-	}
 
 	receiptsCh := make(chan txmgr.TxReceipt[txRef])
 	queue := txmgr.NewQueue[txRef](l.killCtx, l.Txmgr, l.Config.MaxPendingTransactions)

op-proposer/proposer/driver.go

@@ -178,6 +178,13 @@ func (l *L2OutputSubmitter) StartL2OutputSubmitting() error {
 	}
 	l.running = true
 
+	if l.Cfg.WaitNodeSync {
+		err := l.waitNodeSync()
+		if err != nil {
+			return fmt.Errorf("error waiting for node sync: %w", err)
+		}
+	}
+
 	l.wg.Add(1)
 	go l.loop()
 
@@ -429,14 +436,6 @@ func (l *L2OutputSubmitter) loop() {
 	defer l.wg.Done()
 	ctx := l.ctx
 
-	if l.Cfg.WaitNodeSync {
-		err := l.waitNodeSync()
-		if err != nil {
-			l.Log.Error("Error waiting for node sync", "err", err)
-			return
-		}
-	}
-
 	if l.dgfContract == nil {
 		l.loopL2OO(ctx)
 	} else {