Engine API: shorter waits (#13839)

Cherry pick PR #13821 into `main`.  See Issue #13773

turbo/engineapi/engine_server.go

@@ -437,14 +437,14 @@ func (s *EngineServer) getQuickPayloadStatusIfPossible(ctx context.Context, bloc
 		if header != nil && isCanonical {
 			return &engine_types.PayloadStatus{Status: engine_types.ValidStatus, LatestValidHash: &blockHash}, nil
 		}
-		if shouldWait, _ := waitForStuff(func() (bool, error) {
+		if shouldWait, _ := waitForStuff(50*time.Millisecond, func() (bool, error) {
 			return parent == nil && s.hd.PosStatus() == headerdownload.Syncing, nil
 		}); shouldWait {
 			s.logger.Info(fmt.Sprintf("[%s] Downloading some other PoS blocks", prefix), "hash", blockHash)
 			return &engine_types.PayloadStatus{Status: engine_types.SyncingStatus}, nil
 		}
 	} else {
-		if shouldWait, _ := waitForStuff(func() (bool, error) {
+		if shouldWait, _ := waitForStuff(50*time.Millisecond, func() (bool, error) {
 			return header == nil && s.hd.PosStatus() == headerdownload.Syncing, nil
 		}); shouldWait {
 			s.logger.Info(fmt.Sprintf("[%s] Downloading some other PoS stuff", prefix), "hash", blockHash)
@@ -458,7 +458,7 @@ func (s *EngineServer) getQuickPayloadStatusIfPossible(ctx context.Context, bloc
 			return &engine_types.PayloadStatus{Status: engine_types.ValidStatus, LatestValidHash: &blockHash}, nil
 		}
 	}
-	waitingForExecutionReady, err := waitForStuff(func() (bool, error) {
+	waitingForExecutionReady, err := waitForStuff(500*time.Millisecond, func() (bool, error) {
 		isReady, err := s.chainRW.Ready(ctx)
 		return !isReady, err
 	})
@@ -623,7 +623,7 @@ func (s *EngineServer) forkchoiceUpdated(ctx context.Context, forkchoiceState *e
 
 	var resp *execution.AssembleBlockResponse
 
-	execBusy, err := waitForStuff(func() (bool, error) {
+	execBusy, err := waitForStuff(500*time.Millisecond, func() (bool, error) {
 		resp, err = s.executionService.AssembleBlock(ctx, req)
 		if err != nil {
 			return false, err
@@ -753,15 +753,9 @@ func (e *EngineServer) HandleNewPayload(
 		if currentHeadNumber != nil {
 			// We try waiting until we finish downloading the PoS blocks if the distance from the head is enough,
 			// so that we will perform full validation.
-			success := false
-			for i := 0; i < 100; i++ {
-				time.Sleep(10 * time.Millisecond)
-				if e.blockDownloader.Status() == headerdownload.Synced {
-					success = true
-					break
-				}
-			}
-			if !success {
+			if stillSyncing, _ := waitForStuff(500*time.Millisecond, func() (bool, error) {
+				return e.blockDownloader.Status() != headerdownload.Synced, nil
+			}); stillSyncing {
 				return &engine_types.PayloadStatus{Status: engine_types.SyncingStatus}, nil
 			}
 			status, _, latestValidHash, err := e.chainRW.ValidateChain(ctx, headerHash, headerNumber)
@@ -891,15 +885,15 @@ func (e *EngineServer) SetConsuming(consuming bool) {
 	e.consuming.Store(consuming)
 }
 
-func waitForStuff(waitCondnF func() (bool, error)) (bool, error) {
+func waitForStuff(maxWait time.Duration, waitCondnF func() (bool, error)) (bool, error) {
 	shouldWait, err := waitCondnF()
 	if err != nil || !shouldWait {
 		return false, err
 	}
-	// Times out after 8s - loosely based on timeouts of FCU and NewPayload for Ethereum specs
-	// Look for "timeout" in, for instance, https://github.com/ethereum/execution-apis/blob/main/src/engine/cancun.md
-	for i := 0; i < 800; i++ {
-		time.Sleep(10 * time.Millisecond)
+	checkInterval := 10 * time.Millisecond
+	maxChecks := int64(maxWait) / int64(checkInterval)
+	for i := int64(0); i < maxChecks; i++ {
+		time.Sleep(checkInterval)
 		shouldWait, err = waitCondnF()
 		if err != nil || !shouldWait {
 			return shouldWait, err