court erred when it found that his action was barred by Heck v. Humphrey, 512 U.S. 477, 114 S.Ct. 2364, 129 L.Ed.2d 383 (1994). Heck precludes a prisoner’s § 1983 claim that, if successful, would invalidate a conviction or sentence “where that conviction [or sentence] has not been reversed, expunged or called into question by issuance of a writ of habeas corpus.” Smithart v. Towery, 79 F.3d 951, 952 (9th Cir.1996) (citing Heck, 512 U.S. at 486-87, 114 S.Ct. at 2371-72). We previously held that Heck does not bar a prisoner’s § 1983 claim that purports to challenge an allegedly unconstitutional prison hearing solely on the ground that the hearing was procedurally defective. See Gotcher v. Wood, 66 F.3d 1097, 1099 (9th Cir.1995), vacated, — U.S. -, 117 S.Ct. 1840, 137 L.Ed.2d 1045 (1997) (<HOLDING>). That rule was expressly disapproved by the
holding that depriving inmates of statecreated right to goodtime credits in prison disciplinary proceedings requires due process holding that a prisoner cannot be deprived of a protected liberty interest in goodtime credits without procedural due process holding that habeas was the sole vehicle for an inmates constitutional challenge to procedures employed by state officials to deprive him of goodtime credits holding that inmates serving life terms were not entitled to goodtime credits because state statute expressly foreclosed the granting of goodtime credits to such inmates holding that a prisoner who challenged prison procedures used to deny him goodtime credits and not actual denial of those credits stated a cognizable claim under  1983