Sdo_util.to_gmlgeometry on an optimized rectangle with a hole

Question

11.2.0.2 on Linux
This is a bit of an obscure one - I've worked around it, but thought I'd put it up here anyway...
I've got a polygon geometry that is an optimized rectangle outer ring with an optimized rectangle inner ring - I know, very odd and not really a good idea, but it does pass validation:
SQL> select sdo_geom.validate_geometry_with_context(
  2    sdo_geometry(2003, null, null, sdo_elem_info_array(1, 1003, 3, 5, 2003, 3), sdo_ordinate_array(0, 0, 10, 10, 0.5, 0.5, 9.5, 9.5)),
  3    0.005) as valid
  4  from dual;
VALID
TRUE
sdo_util.to_gmlgeometry produces a sensible result:
SQL> select sdo_util.to_gmlgeometry(
  2    sdo_geometry(2003, null, null, sdo_elem_info_array(1, 1003, 3, 5, 2003, 3), sdo_ordinate_array(0, 0, 10, 10, 0.5, 0.5, 9.5, 9.5))) as gml
  3  from dual;
GML
<gml:Polygon srsName="SDO:" xmlns:gml="http://www.opengis.net/gml">
  <gml:outerBoundaryIs>
  <gml:LinearRing>
  <gml:coordinates decimal="." cs="," ts=" ">0.0,0.0 10.0,0.0 10.0,10.0 0.0,10.0 0.0,0.0 </gml:coordinates>
  </gml:LinearRing>
  </gml:outerBoundaryIs>
  <gml:innerBoundaryIs>
  <gml:LinearRing>
  <gml:coordinates decimal="." cs="," ts=" ">0.5,0.5 0.5,9.5 9.5,9.5 9.5,0.5 0.5,0.5 </gml:coordinates>
  </gml:LinearRing>
  </gml:innerBoundaryIs>
</gml:Polygon>
But sdo_util.to_wktgeometry makes a dogs dinner of it:
SQL> select sdo_util.to_wktgeometry(
  2    sdo_geometry(2003, null, null, sdo_elem_info_array(1, 1003, 3, 5, 2003, 3), sdo_ordinate_array(0, 0, 10, 10, 0.5, 0.5, 9.5, 9.5))) as wkt
  3  from dual;
WKT
POLYGON ((0.0 0.0, 10.0 0.0, 10.0 10.0, 0.0 10.0, 0.0 0.0))
Looks like a bug in sdo_util.to_wktgeometry?
We'll get around it by writing these geometries out in the long format, but I'd expect sdo_util.to_wktgeometry to handle it nonetheless.
John

Answer 1

Same on 12.1.1.0 too.
PDB1@ORCL> select banner from v$version;
BANNER
Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production
PL/SQL Release 12.1.0.1.0 - Production
CORE 12.1.0.1.0 Production
TNS for Linux: Version 12.1.0.1.0 - Production
NLSRTL Version 12.1.0.1.0 - Production
PDB1@ORCL> select sdo_util.to_wktgeometry(
  sdo_geometry(2003, null, null, sdo_elem_info_array(1, 1003, 3, 5, 2003, 3),
  sdo_ordinate_array(0, 0, 10, 10, 0.5, 0.5, 9.5, 9.5))) as wkt
from dual;  2    3    4 
WKT
POLYGON ((0.0 0.0, 10.0 0.0, 10.0 10.0, 0.0 10.0, 0.0 0.0))