LP:801475 - ST_UNION() does not perform duplicate weedout in maria-5.3-gis

ST_UNION does not perform duplicate weedout. The union of 2 identical POINTs is returned as a MULTIPOINT containing 2 identical POINTS. Postgis returns a single POINT.

SELECT AsText( ST_UNION( GeometryFromText(' POINT( 4 4 ) ') , GeometryFromText(' POINT( 4 4 ) ') ) );

returns:

MULTIPOINT(4 4,4 4)