Okla. Stat. tit. 22, § 1084
If the application cannot be disposed of on the pleadings and record, or there exists a material issue of fact, the court shall conduct an evidentiary hearing at which time a record shall be made and preserved. The court may receive proof by affidavits, depositions, oral testimony, or other evidence and may order the applicant brought before it for the hearing. A judge should not preside at such a hearing if his testimony is material. The court shall make specific findings of fact, and state expressly its conclusions of law, relating to each issue presented. This order is a final judgment.
Laws 1970, SB 604, c. 220, § 5, emerg. eff. July 1, 1970.