§ 903. Necessary defendants. Each of the following persons shall be
made a party to the action:

1. Every person having an undivided share, in possession or otherwise,
in the property, as tenant in fee, for life, by the curtesy or for
years;

2. Every person entitled to the reversion, remainder or inheritance of
an undivided share, after the determination of a particular estate
therein;

3. Every person who, by any contingency, is or may become entitled to
a beneficial interest in an undivided share in the property, provided
that where a future estate or interest is limited in any contingency to
the persons who shall compose a certain class upon the happening of a
future event, it shall be sufficient to make parties to the action the
persons who would have been entitled to such estate or interest if such
event had happened immediately before the commencement of the action;

4. Every person having an inchoate right of dower in an undivided
share in the property;

5. Every person having a right of dower in the property, or any part
thereof, which has not been admeasured; and

6. An executor or administrator, where letters testamentary or of
administration have been issued on the estate of the decedent from whom
the plaintiff's title to the real property is derived, and the action is
brought within eighteen months after such letters were issued; or where
the person of whose estate the executor or administrator has been
appointed should, if living, be a party to the action. If no executor or
administrator has been appointed for the estate of such a person, that
fact must be stated in the complaint.