(a) On approval by the commissioner, bonds issued under Subchapter A by a school district or Chapter 53 for a charter district, including refunding and refinanced bonds, are guaranteed by the corpus and income of the permanent school fund.
(b) Notwithstanding any amendment of this subchapter or other law, the guarantee under this subchapter of school district or charter district bonds remains in effect until the date those bonds mature or are defeased in accordance with state law.