src/server/pkg/cmdutil/cobra.go
func ParseBranch(arg string) (*pfs.Branch, error) {
	commit, err := ParseCommit(arg)
	if err != nil {
		return nil, err
	}
	return &pfs.Branch{Repo: commit.Repo, Name: commit.ID}, nil
}
func ParseBranch(arg string) (*pfs.Branch, error) {
	commit, err := ParseCommit(arg)
	if err != nil {
		return nil, err
	}
	return &pfs.Branch{Repo: commit.Repo, Name: commit.ID}, nil
}
// ParseBranch takes an argument of the form "repo[@branch]" and
// returns the corresponding *pfs.Branch.  This uses ParseCommit under the hood
// because a branch name is usually interchangeable with a commit-id.