Which person is expressly eligible under section 15(e) of the Specific Relief Act, 1963 to seek specific performance of a contract?

Section 15(e) lets "a reversioner in possession" obtain specific performance where the agreement is a covenant entered into with his predecessor in title and he is entitled to its benefit. Section 15 lists only the parties and persons claiming through them or specially connected with the contract, such as representatives in interest, beneficiaries of marriage settlements, remaindermen and reversioners. A stranger who merely benefits, a creditor of a party and an attesting witness are not among them, so none of them can sue for specific performance.