From 6bd6799a1e38cadeed301217545de0347278c06e Mon Sep 17 00:00:00 2001
From: healthykim <bsbs8645@snu.ac.kr>
Date: Mon, 20 Apr 2026 09:49:26 +0200
Subject: [PATCH] eth/downloader: refactor

---
 eth/downloader/fetchers_concurrent.go | 46 ++++++++++++++-------------
 1 file changed, 24 insertions(+), 22 deletions(-)

diff --git a/eth/downloader/fetchers_concurrent.go b/eth/downloader/fetchers_concurrent.go
index 9d95eec3ee..e01b8df048 100644
--- a/eth/downloader/fetchers_concurrent.go
+++ b/eth/downloader/fetchers_concurrent.go
@@ -325,30 +325,25 @@ func (d *Downloader) concurrentFetch(queue typedQueue) error {
 
 			// If the peer was previously banned and failed to deliver its pack
 			// in a reasonable time frame, ignore its message.
-			if peer := d.peers.Peer(res.Req.Peer); peer != nil {
-				// Deliver the received chunk of data and check chain validity
-				accepted, err := queue.deliver(peer, res)
-				if errors.Is(err, errInvalidChain) {
-					res.Done <- err
-					res.Req.Close()
-					return err
-				}
-				if errors.Is(err, errInvalidBody) || errors.Is(err, errInvalidReceipt) {
-					// Signal the dispatcher with the error to drop the peer.
-					res.Done <- err
-					res.Req.Close()
-					continue
-				}
-				// Unless a peer delivered something completely else than requested (usually
-				// caused by a timed out request which came through in the end), set it to
-				// idle. If the delivery's stale, the peer should have already been idled.
-				if !errors.Is(err, errStaleDelivery) {
-					queue.updateCapacity(peer, accepted, res.Time)
-				}
+			peer := d.peers.Peer(res.Req.Peer)
+			if peer == nil {
+				res.Done <- nil
+				res.Req.Close()
+				continue
 			}
-			// Signal the dispatcher that the round trip is done.
-			res.Done <- nil
+			// Deliver the received chunk of data and check chain validity
+			accepted, err := queue.deliver(peer, res)
+			// Unless a peer delivered something completely else than requested (usually
+			// caused by a timed out request which came through in the end), set it to
+			// idle. If the delivery's stale, the peer should have already been idled.
+			if !errors.Is(err, errStaleDelivery) {
+				queue.updateCapacity(peer, accepted, res.Time)
+			}
+			res.Done <- errorOfRequest(err)
 			res.Req.Close()
+			if errors.Is(err, errInvalidChain) {
+				return err
+			}
 
 		case cont := <-queue.waker():
 			// The header fetcher sent a continuation flag, check if it's done
@@ -358,3 +353,10 @@ func (d *Downloader) concurrentFetch(queue typedQueue) error {
 		}
 	}
 }
+
+func errorOfRequest(err error) error {
+	if errors.Is(err, errInvalidBody) || errors.Is(err, errInvalidReceipt) {
+		return err
+	}
+	return nil
+}