Function checkFastForwardUpdate

remote.go:1097–1121

(s storer.EncodedObjectStorer, remoteRefs storer.ReferenceStorer, cmd *packp.Command)

}

func checkFastForwardUpdate(s storer.EncodedObjectStorer, remoteRefs storer.ReferenceStorer, cmd *packp.Command) error {
	if cmd.Old == plumbing.ZeroHash {
		_, err := remoteRefs.Reference(cmd.Name)
		if err == plumbing.ErrReferenceNotFound {
			return nil
		}

		if err != nil {
			return err
		}

		return fmt.Errorf("non-fast-forward update: %s", cmd.Name.String())
	}

	ff, err := isFastForward(s, cmd.Old, cmd.New, nil)
	if err != nil {
		return err
	}

	if !ff {
		return fmt.Errorf("non-fast-forward update: %s", cmd.Name.String())
	}

	return nil
}

func isFastForward(s storer.EncodedObjectStorer, old, new plumbing.Hash, earliestShallow *plumbing.Hash) (bool, error) {
	c, err := object.GetCommit(s, new)