write file info only when data is not empty

go/storage/needle_read_write.go

@@ -87,7 +87,6 @@ func (n *Needle) Append(w io.Writer, version Version) (size uint32, err error) {
 			if _, err = w.Write(header[0:1]); err != nil {
 				return
 			}
-		}
 			if n.HasName() {
 				util.Uint8toBytes(header[0:1], n.NameSize)
 				if _, err = w.Write(header[0:1]); err != nil {
@@ -112,6 +111,7 @@ func (n *Needle) Append(w io.Writer, version Version) (size uint32, err error) {
 					return
 				}
 			}
+		}
 		padding := NeedlePaddingSize - ((NeedleHeaderSize + n.Size + NeedleChecksumSize) % NeedlePaddingSize)
 		util.Uint32toBytes(header[0:NeedleChecksumSize], n.Checksum.Value())
 		_, err = w.Write(header[0 : NeedleChecksumSize+padding])