QgsGmlStreamingParser: fix parsing of GML geometries with srsDimension='3' set on posList element (fixes #21335)

Author: rouault

src/core/qgsgml.cpp

@@ -815,11 +815,14 @@ void QgsGmlStreamingParser::startElement( const XML_Char *el, const XML_Char **a
     }
   }
 
-  if ( elDimension != 0 )
+  if ( elDimension != 0 || mDimensionStack.isEmpty() )
   {
-    mDimension = elDimension;
+    mDimensionStack.push( elDimension );
+  }
+  else
+  {
+    mDimensionStack.push( mDimensionStack.back() );
   }
-  mDimensionStack.push( mDimension );
 
   if ( mEpsg == 0 && isGeom )
   {
@@ -847,7 +850,7 @@ void QgsGmlStreamingParser::endElement( const XML_Char *el )
   const int localNameLen = ( pszSep ) ? ( int )( elLen - nsLen ) - 1 : elLen;
   ParseMode parseMode( mParseModeStack.isEmpty() ? None : mParseModeStack.top() );
 
-  mDimension = mDimensionStack.isEmpty() ? 0 : mDimensionStack.pop();
+  int lastDimension = mDimensionStack.isEmpty() ? 0 : mDimensionStack.pop();
 
   const bool isGMLNS = ( nsLen == mGMLNameSpaceURI.size() && mGMLNameSpaceURIPtr && memcmp( el, mGMLNameSpaceURIPtr, nsLen ) == 0 );
 
@@ -858,6 +861,7 @@ void QgsGmlStreamingParser::endElement( const XML_Char *el )
   else if ( parseMode == PosList && isGMLNS &&
             ( LOCALNAME_EQUALS( "pos" ) || LOCALNAME_EQUALS( "posList" ) ) )
   {
+    mDimension = lastDimension;
     mParseModeStack.pop();
   }
   else if ( parseMode == AttributeTuple &&

tests/src/core/testqgsgml.cpp

@@ -64,6 +64,7 @@ class TestQgsGML : public QObject
     void testLineStringGML3_LineStringSegment();
     void testPolygonGML3();
     void testPolygonGML3_srsDimension_on_Polygon();
+    void testPolygonGML3_srsDimension_on_posList();
     void testMultiLineStringGML3();
     void testMultiPolygonGML3();
     void testPointGML3_2();
@@ -660,6 +661,38 @@ void TestQgsGML::testPolygonGML3_srsDimension_on_Polygon()
   delete features[0].first;
 }
 
+void TestQgsGML::testPolygonGML3_srsDimension_on_posList()
+{
+  QgsFields fields;
+  QgsGmlStreamingParser gmlParser( QStringLiteral( "mytypename" ), QStringLiteral( "mygeom" ), fields );
+  QCOMPARE( gmlParser.processData( QByteArray( "<myns:FeatureCollection "
+                                   "xmlns:myns='http://myns' "
+                                   "xmlns:gml='http://www.opengis.net/gml'>"
+                                   "<gml:featureMember>"
+                                   "<myns:mytypename fid='mytypename.1'>"
+                                   "<myns:mygeom>"
+                                   "<gml:Polygon srsName='EPSG:27700'>"
+                                   "<gml:exterior>"
+                                   "<gml:LinearRing>"
+                                   "<gml:posList srsDimension='3'>0 0 -100 0 10 -100 10 10 -100 10 0 -100 0 0 -100</gml:posList>"
+                                   "</gml:LinearRing>"
+                                   "</gml:exterior>"
+                                   "</gml:Polygon>"
+                                   "</myns:mygeom>"
+                                   "</myns:mytypename>"
+                                   "</gml:featureMember>"
+                                   "</myns:FeatureCollection>" ), true ), true );
+  QCOMPARE( gmlParser.wkbType(), QgsWkbTypes::Polygon );
+  QVector<QgsGmlStreamingParser::QgsGmlFeaturePtrGmlIdPair> features = gmlParser.getAndStealReadyFeatures();
+  QCOMPARE( features.size(), 1 );
+  QVERIFY( features[0].first->hasGeometry() );
+  QCOMPARE( features[0].first->geometry().wkbType(), QgsWkbTypes::Polygon );
+  QgsPolygonXY poly = features[0].first->geometry().asPolygon();
+  QCOMPARE( poly.size(), 1 );
+  QCOMPARE( poly[0].size(), 5 );
+  delete features[0].first;
+}
+
 void TestQgsGML::testMultiLineStringGML3()
 {
   QgsFields fields;