code: func resolveGitStorageDir(gitDir string) string {
  	commondirpath := filepath.Join(gitDir, "commondir")
  	if tools.FileExists(commondirpath) && !tools.DirExists(filepath.Join(gitDir, "objects")) {
  		// no git-dir: prefix in commondir
  		storage, err := processGitRedirectFile(commondirpath, "")
  		if err == nil {
  			return storage
  		}
  	}
  	return gitDir
  }
docs: // From a git dir, get the location that objects are to be stored (we will store lfs alongside)
  // Sometimes there is an additional level of redirect on the .git folder by way of a commondir file
  // before you find object storage, e.g. 'git worktree' uses this. It redirects to gitdir either by GIT_DIR
  // (during setup) or .git/git-dir: (during use), but this only contains the index etc, the objects
  // are found in another git dir via 'commondir'.