[postgis-users] GML ver 3 id duplicated error

[Michal Seidl]

Hello,
we use POSTGIS="3.3.1 3786b21" and have problem with validation of GML 
geometry. The validator complains about duplicated "id" values in 
generated XML in MultiSuface and Polygon.

<gml:MultiSurface srsName="EPSG:4326" gml:id="1">
   <gml:surfaceMember>
     <gml:Polygon gml:id="1">
       <gml:exterior>
         <gml:LinearRing>
          <gml:posList srsDimension="2">0 0 0 1 1 1 1 0 0 
0</gml:posList>
         </gml:LinearRing>
        </gml:exterior>
     </gml:Polygon>
   </gml:surfaceMember>
</gml:MultiSurface>

We have not found definition for GML ver 3.1.1 but for 3.2.1 by this 
link 
https://docs.geoserver.org/2.23.x/en/user/data/app-schema/supported-gml-versions.html 
says:

If a multigeometry (such as a MultiPoint or MultiSurface) is assigned a 
gml:id of (for example) parentid, to permit GML 3.2.1 schema-validity, 
each geometry that the multigeometry contains will be automatically 
assigned a gml:id of the form parentid.1, parentid.2, … in order.

Is it Postgis bug or difference between GML ver 3.1.1 and 3.2.1?

Thanks for help Michal S.