fix(analyze): write StoredDir stats under the dir mutex

pkg/analyze/stored.go

@@ -352,27 +352,45 @@ func (f *StoredDir) updateStats(linkedItems fs.HardLinkedItems, filteringFiles b
 	var itemCount int64
 	f.cachedFiles = nil
 	files := f.loadFiles()
+
+	// Snapshot the mutable stat fields under the read lock and commit them back
+	// under the write lock, mirroring Dir.updateStats. Readers of these fields
+	// (GetSize, GetUsage, GetFlag, GetMtime, GetItemCount) all take f.m, so the
+	// writes here must take it too, e.g. when the stats are recomputed while a
+	// preview reads the same directory mid-scan.
+	f.m.RLock()
+	mtime := f.Mtime
+	flag := f.Flag
+	f.m.RUnlock()
+
 	for _, entry := range files {
 		count, size, usage := entry.GetItemStats(linkedItems, filteringFiles)
 		totalSize += size
 		totalUsage += usage
 		itemCount += count
 
-		if entry.GetMtime().After(f.Mtime) {
-			f.Mtime = entry.GetMtime()
+		entryMtime := entry.GetMtime()
+		if entryMtime.After(mtime) {
+			mtime = entryMtime
 		}
 
 		switch entry.GetFlag() {
 		case '!', '.':
-			if f.Flag != '!' {
-				f.Flag = '.'
+			if flag != '!' {
+				flag = '.'
 			}
 		}
 	}
 	f.cachedFiles = nil
+
+	f.m.Lock()
+	f.Mtime = mtime
+	f.Flag = flag
 	f.ItemCount = itemCount + 1
 	f.Size = totalSize
 	f.Usage = totalUsage
+	f.m.Unlock()
+
 	err := DefaultStorage.StoreDir(f)
 	if err != nil {
 		log.Print(err.Error())