What is the ruling on swearing an oath by divorce in an urfi marriage, what are the marital rights resulting from it, and when is this marriage considered valid?

If an urfi marriage fulfills the pillars of a legal contract—namely, a guardian (wali), two just witnesses, and a formula (sigha)—then it is valid, and its effects and rights are established. As for swearing by divorce, it is unlawful, but if it occurs and the husband breaks his oath, his wife is divorced. However, if the urfi marriage is intended to mean a marriage whose pillars are not complete, then it is invalid and must be annulled.