@zeripath Before applying commit "720c192", these codes works:

_, err := git.PlainClone(pkgDir, false, &git.CloneOptions{
  URL:               "https://github.com/rime/rime-cantonese",
  ReferenceName:     plumbing.NewBranchReferenceName("master"),
  RecurseSubmodules: git.DefaultSubmoduleRecursionDepth,
  Depth:             1})
fmt.Println(err)
nil

After the commit, these codes return a "object not found" error.

Because now the 3mb file "jyut6ping3.dict.yaml" in commit tree object can't not have a blob Reader().

That is, the b.obj.Reader() function in plumbing/object/object.go can't return a valid io.ReadCloser and nil error now.