OGR ExportToGML creates invalid GML for CurvePolygon

[CodeBardian]

Using ExportToGML on a simple CurvePolygon consisting of one circular string and a straight segment produces an invalid GML representation. Consider this simple code snippet to reproduce the issue:

wkt = 'CURVEPOLYGON (COMPOUNDCURVE ((0 -1,0 1),CIRCULARSTRING (0 1,1 0,0 -1)))'
geom = ogr.CreateGeometryFromWkt(wkt)

gml = geom.ExportToGML(options=["FORMAT=GML32", "GMLID=test", "SPACE_INDENTATION=YES"])
print(gml)

Expected behavior and actual behavior.

Actual: The code above generates the following GML which I believe is invalid under GML 3.2 specification:

<gml:Polygon gml:id="test">
  <gml:exterior>
    <gml:CompositeCurve>
      <gml:curveMember>
        <gml:LineString>
          <gml:posList>0 -1 0 1</gml:posList>
        </gml:LineString>
      </gml:curveMember>
      <gml:curveMember>
        <gml:Curve>
          <gml:segments>
            <gml:ArcString>
              <gml:posList>0 1 1 0 0 -1</gml:posList>
            </gml:ArcString>
          </gml:segments>
        </gml:Curve>
      </gml:curveMember>
    </gml:CompositeCurve>
  </gml:exterior>
</gml:Polygon>

Expected: gml:exterior expects child elements of type gml:AbstractRing (e.g. Ring or LinearRing) not CompositeCurve. In addition the GML validation expects the gml:id attribute to be present on both curve member geometries.

This would satisfy the GML validator:

<gml:Polygon gml:id="test">
  <gml:exterior>
    <gml:Ring>
      <gml:curveMember>
        <gml:LineString gml:id="test.0">
          <gml:posList>0 -1 0 1</gml:posList>
        </gml:LineString>
      </gml:curveMember>
      <gml:curveMember>
        <gml:Curve gml:id="test.1">
          <gml:segments>
            <gml:ArcString>
              <gml:posList>0 1 1 0 0 -1</gml:posList>
            </gml:ArcString>
          </gml:segments>
        </gml:Curve>
      </gml:curveMember>
    </gml:Ring>
  </gml:exterior>
</gml:Polygon>

Operating system

Ubuntu 22.04.1, Windows 11

GDAL version and provenance

3.4.1 (within QGIS 3.22)