.

wcfs/internal/zdata/δftail.go

@@ -467,7 +467,7 @@ func (δFtail *ΔFtail) SliceByFileRev(zfile *ZBigFile, lo, hi zodb.Tid) /*reado
 			if ZinblkAt <= δZ.Rev {
 				for _, oid := range δZ.Changev {
 					inblk, ok := Zinblk[oid]
-					if ok {
+					if ok && len(inblk) != 0 {
 						δf := vδfTail(δZ.Rev)
 						δf.Blocks.Update(inblk)
 					}