Set existing torrent webseeds after download (#10149)

Fix a timing hole where torrents that get created before webseeds have
been downloaded don't get webseeds set.

erigon-lib/downloader/downloader.go

@@ -819,6 +819,15 @@ func (d *Downloader) mainLoop(silent bool) error {
 			if err := d.addTorrentFilesFromDisk(true); err != nil && !errors.Is(err, context.Canceled) {
 				d.logger.Warn("[snapshots] addTorrentFilesFromDisk", "err", err)
 			}
+
+			d.lock.Lock()
+			defer d.lock.Unlock()
+
+			for _, t := range d.torrentClient.Torrents() {
+				if urls, ok := d.webseeds.ByFileName(t.Name()); ok {
+					t.AddWebSeeds(urls)
+				}
+			}
 		}()
 	}
 

erigon-lib/downloader/webseed.go

@@ -35,8 +35,7 @@ type WebSeeds struct {
 	torrentUrls         snaptype.TorrentUrls // HTTP urls of .torrent files
 	downloadTorrentFile bool
 	torrentsWhitelist   snapcfg.Preverified
-
-	seeds []*url.URL
+	seeds               []*url.URL
 
 	logger    log.Logger
 	verbosity log.Lvl
@@ -97,10 +96,10 @@ func (d *WebSeeds) getWebDownloadInfo(ctx context.Context, t *torrent.Torrent) (
 	return infos, seedHashMismatches, nil
 }
 
-func (d *WebSeeds) SetTorrent(t *AtomicTorrentFS, whiteList snapcfg.Preverified, downloadTorrentFile bool) {
+func (d *WebSeeds) SetTorrent(torrentFS *AtomicTorrentFS, whiteList snapcfg.Preverified, downloadTorrentFile bool) {
 	d.downloadTorrentFile = downloadTorrentFile
 	d.torrentsWhitelist = whiteList
-	d.torrentFiles = t
+	d.torrentFiles = torrentFS
 }
 
 func (d *WebSeeds) checkHasTorrents(manifestResponse snaptype.WebSeedsFromProvider, report *WebSeedCheckReport) {
@@ -405,8 +404,8 @@ func (d *WebSeeds) makeWebSeedUrls(listsOfFiles []snaptype.WebSeedsFromProvider,
 	}
 
 	d.lock.Lock()
-	defer d.lock.Unlock()
 	d.byFileName = webSeedUrls
+	d.lock.Unlock()
 }
 
 func (d *WebSeeds) TorrentUrls() snaptype.TorrentUrls {