diff --git a/python/core/geometry/qgsabstractgeometry.sip b/python/core/geometry/qgsabstractgeometry.sip
index 0fa299815ff..55e4fe08c0d 100644
--- a/python/core/geometry/qgsabstractgeometry.sip
+++ b/python/core/geometry/qgsabstractgeometry.sip
@@ -269,7 +269,7 @@ class QgsAbstractGeometry
  :rtype: bool
 %End
 
-    virtual void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex /Out/, QgsVertexId &nextVertex /Out/ ) = 0;
+    virtual void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex /Out/, QgsVertexId &nextVertex /Out/ ) const = 0;
 %Docstring
  Returns the vertices adjacent to a specified ``vertex`` within a geometry.
 .. versionadded:: 3.0
diff --git a/python/core/geometry/qgscurve.sip b/python/core/geometry/qgscurve.sip
index 647823ce7a8..f325e79b3a5 100644
--- a/python/core/geometry/qgscurve.sip
+++ b/python/core/geometry/qgscurve.sip
@@ -102,7 +102,7 @@ class QgsCurve: QgsAbstractGeometry
 
     virtual bool nextVertex( QgsVertexId &id, QgsPoint &vertex /Out/ ) const;
 
-    virtual void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex /Out/, QgsVertexId &nextVertex /Out/ );
+    virtual void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex /Out/, QgsVertexId &nextVertex /Out/ ) const;
 
     virtual int vertexNumberFromVertexId( QgsVertexId id ) const;
 
diff --git a/python/core/geometry/qgscurvepolygon.sip b/python/core/geometry/qgscurvepolygon.sip
index 3f1fabcc915..dddd0fe39bb 100644
--- a/python/core/geometry/qgscurvepolygon.sip
+++ b/python/core/geometry/qgscurvepolygon.sip
@@ -152,7 +152,7 @@ Adds an interior ring to the geometry (takes ownership)
 
     virtual bool nextVertex( QgsVertexId &id, QgsPoint &vertex /Out/ ) const;
 
-    virtual void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex /Out/, QgsVertexId &nextVertex /Out/ );
+    virtual void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex /Out/, QgsVertexId &nextVertex /Out/ ) const;
 
     virtual bool hasCurvedSegments() const;
 
diff --git a/python/core/geometry/qgsgeometry.sip b/python/core/geometry/qgsgeometry.sip
index 014370ff1aa..7fada2032ed 100644
--- a/python/core/geometry/qgsgeometry.sip
+++ b/python/core/geometry/qgsgeometry.sip
@@ -84,19 +84,50 @@ Copy constructor will prompt a deep copy of the object
 
     ~QgsGeometry();
 
-    QgsAbstractGeometry *geometry() const;
+    const QgsAbstractGeometry *constGet() const;
 %Docstring
- Returns the underlying geometry store.
-.. versionadded:: 2.10
-.. seealso:: setGeometry
+ Returns a non-modifiable (const) reference to the underlying abstract geometry primitive.
+
+ This is much faster then calling the non-const get() method.
+
+.. note::
+
+   In QGIS 2.x this method was named geometry().
+
+.. versionadded:: 3.0
+.. seealso:: primitive()
+.. seealso:: set()
  :rtype: QgsAbstractGeometry
 %End
 
-    void setGeometry( QgsAbstractGeometry *geometry /Transfer/ );
+    QgsAbstractGeometry *get();
+%Docstring
+ Returns a modifiable (non-const) reference to the underlying abstract geometry primitive.
+
+ This method can be slow to call, as it may trigger a detachment of the geometry
+ and a deep copy. Where possible, use constGet() instead.
+
+.. note::
+
+   In QGIS 2.x this method was named geometry().
+
+.. versionadded:: 3.0
+.. seealso:: constGet()
+.. seealso:: set()
+ :rtype: QgsAbstractGeometry
+%End
+
+    void set( QgsAbstractGeometry *geometry /Transfer/ );
 %Docstring
  Sets the underlying geometry store. Ownership of geometry is transferred.
-.. versionadded:: 2.10
-.. seealso:: geometry
+
+.. note::
+
+   In QGIS 2.x this method was named setGeometry().
+
+.. versionadded:: 3.0
+.. seealso:: get()
+.. seealso:: constGet()
 %End
 
     bool isNull() const;
diff --git a/python/core/geometry/qgsgeometrycollection.sip b/python/core/geometry/qgsgeometrycollection.sip
index b90f2100078..60cc72d7a31 100644
--- a/python/core/geometry/qgsgeometrycollection.sip
+++ b/python/core/geometry/qgsgeometrycollection.sip
@@ -53,7 +53,7 @@ class QgsGeometryCollection: QgsAbstractGeometry
 
     virtual QgsAbstractGeometry *boundary() const /Factory/;
 
-    virtual void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex /Out/, QgsVertexId &nextVertex /Out/ );
+    virtual void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex /Out/, QgsVertexId &nextVertex /Out/ ) const;
 
     virtual int vertexNumberFromVertexId( QgsVertexId id ) const;
 
diff --git a/python/core/geometry/qgspoint.sip b/python/core/geometry/qgspoint.sip
index 70fda7507f8..f67a10c5548 100644
--- a/python/core/geometry/qgspoint.sip
+++ b/python/core/geometry/qgspoint.sip
@@ -380,7 +380,7 @@ class QgsPoint: QgsAbstractGeometry
 
     virtual bool nextVertex( QgsVertexId &id, QgsPoint &vertex /Out/ ) const;
 
-    virtual void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex /Out/, QgsVertexId &nextVertex /Out/ );
+    virtual void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex /Out/, QgsVertexId &nextVertex /Out/ ) const;
 
 
     virtual double vertexAngle( QgsVertexId vertex ) const;
diff --git a/src/analysis/network/qgsvectorlayerdirector.cpp b/src/analysis/network/qgsvectorlayerdirector.cpp
index 3682db89568..e1dd8e254d4 100644
--- a/src/analysis/network/qgsvectorlayerdirector.cpp
+++ b/src/analysis/network/qgsvectorlayerdirector.cpp
@@ -165,9 +165,9 @@ void QgsVectorLayerDirector::makeGraph( QgsGraphBuilderInterface *builder, const
     }
 
     QgsMultiPolyline mpl;
-    if ( QgsWkbTypes::flatType( feature.geometry().geometry()->wkbType() ) == QgsWkbTypes::MultiLineString )
+    if ( QgsWkbTypes::flatType( feature.geometry().wkbType() ) == QgsWkbTypes::MultiLineString )
       mpl = feature.geometry().asMultiPolyline();
-    else if ( QgsWkbTypes::flatType( feature.geometry().geometry()->wkbType() ) == QgsWkbTypes::LineString )
+    else if ( QgsWkbTypes::flatType( feature.geometry().wkbType() ) == QgsWkbTypes::LineString )
       mpl.push_back( feature.geometry().asPolyline() );
 
     QgsMultiPolyline::iterator mplIt;
@@ -308,9 +308,9 @@ void QgsVectorLayerDirector::makeGraph( QgsGraphBuilderInterface *builder, const
 
     // begin features segments and add arc to the Graph;
     QgsMultiPolyline mpl;
-    if ( QgsWkbTypes::flatType( feature.geometry().geometry()->wkbType() ) == QgsWkbTypes::MultiLineString )
+    if ( QgsWkbTypes::flatType( feature.geometry().wkbType() ) == QgsWkbTypes::MultiLineString )
       mpl = feature.geometry().asMultiPolyline();
-    else if ( QgsWkbTypes::flatType( feature.geometry().geometry()->wkbType() ) == QgsWkbTypes::LineString )
+    else if ( QgsWkbTypes::flatType( feature.geometry().wkbType() ) == QgsWkbTypes::LineString )
       mpl.push_back( feature.geometry().asPolyline() );
 
     QgsMultiPolyline::iterator mplIt;
diff --git a/src/analysis/processing/qgsalgorithmboundary.cpp b/src/analysis/processing/qgsalgorithmboundary.cpp
index a5ea9f62c51..3fb46c6a388 100644
--- a/src/analysis/processing/qgsalgorithmboundary.cpp
+++ b/src/analysis/processing/qgsalgorithmboundary.cpp
@@ -97,7 +97,7 @@ QgsFeature QgsBoundaryAlgorithm::processFeature( const QgsFeature &feature, QgsP
   if ( feature.hasGeometry() )
   {
     QgsGeometry inputGeometry = feature.geometry();
-    QgsGeometry outputGeometry = QgsGeometry( inputGeometry.geometry()->boundary() );
+    QgsGeometry outputGeometry = QgsGeometry( inputGeometry.constGet()->boundary() );
     if ( !outputGeometry )
     {
       feedback->reportError( QObject::tr( "No boundary for feature %1 (possibly a closed linestring?)'" ).arg( feature.id() ) );
diff --git a/src/analysis/processing/qgsalgorithmclip.cpp b/src/analysis/processing/qgsalgorithmclip.cpp
index d9f4e988750..0e1766ad647 100644
--- a/src/analysis/processing/qgsalgorithmclip.cpp
+++ b/src/analysis/processing/qgsalgorithmclip.cpp
@@ -109,7 +109,7 @@ QVariantMap QgsClipAlgorithm::processAlgorithm( const QVariantMap &parameters, Q
   }
 
   // use prepared geometries for faster intersection tests
-  std::unique_ptr< QgsGeometryEngine > engine( QgsGeometry::createGeometryEngine( combinedClipGeom.geometry() ) );
+  std::unique_ptr< QgsGeometryEngine > engine( QgsGeometry::createGeometryEngine( combinedClipGeom.constGet() ) );
   engine->prepareGeometry();
 
   QgsFeatureIds testedFeatureIds;
@@ -154,15 +154,15 @@ QVariantMap QgsClipAlgorithm::processAlgorithm( const QVariantMap &parameters, Q
       }
       testedFeatureIds.insert( inputFeature.id() );
 
-      if ( !engine->intersects( inputFeature.geometry().geometry() ) )
+      if ( !engine->intersects( inputFeature.geometry().constGet() ) )
         continue;
 
       QgsGeometry newGeometry;
-      if ( !engine->contains( inputFeature.geometry().geometry() ) )
+      if ( !engine->contains( inputFeature.geometry().constGet() ) )
       {
         QgsGeometry currentGeometry = inputFeature.geometry();
         newGeometry = combinedClipGeom.intersection( currentGeometry );
-        if ( newGeometry.wkbType() == QgsWkbTypes::Unknown || QgsWkbTypes::flatType( newGeometry.geometry()->wkbType() ) == QgsWkbTypes::GeometryCollection )
+        if ( newGeometry.wkbType() == QgsWkbTypes::Unknown || QgsWkbTypes::flatType( newGeometry.wkbType() ) == QgsWkbTypes::GeometryCollection )
         {
           QgsGeometry intCom = inputFeature.geometry().combine( newGeometry );
           QgsGeometry intSym = inputFeature.geometry().symDifference( newGeometry );
diff --git a/src/analysis/processing/qgsalgorithmconvexhull.cpp b/src/analysis/processing/qgsalgorithmconvexhull.cpp
index 405b8983891..382d22dc321 100644
--- a/src/analysis/processing/qgsalgorithmconvexhull.cpp
+++ b/src/analysis/processing/qgsalgorithmconvexhull.cpp
@@ -76,8 +76,8 @@ QgsFeature QgsConvexHullAlgorithm::processFeature( const QgsFeature &feature, Qg
     if ( outputGeometry )
     {
       QgsAttributes attrs = f.attributes();
-      attrs << outputGeometry.geometry()->area()
-            << outputGeometry.geometry()->perimeter();
+      attrs << outputGeometry.constGet()->area()
+            << outputGeometry.constGet()->perimeter();
       f.setAttributes( attrs );
     }
   }
diff --git a/src/analysis/processing/qgsalgorithmdropmzvalues.cpp b/src/analysis/processing/qgsalgorithmdropmzvalues.cpp
index 811999a0c49..6075298f516 100644
--- a/src/analysis/processing/qgsalgorithmdropmzvalues.cpp
+++ b/src/analysis/processing/qgsalgorithmdropmzvalues.cpp
@@ -82,7 +82,7 @@ QgsFeature QgsDropMZValuesAlgorithm::processFeature( const QgsFeature &feature,
   QgsFeature f = feature;
   if ( f.hasGeometry() )
   {
-    std::unique_ptr< QgsAbstractGeometry > newGeom( f.geometry().geometry()->clone() );
+    std::unique_ptr< QgsAbstractGeometry > newGeom( f.geometry().constGet()->clone() );
     if ( mDropM )
       newGeom->dropMValue();
     if ( mDropZ )
diff --git a/src/analysis/processing/qgsalgorithmextractbylocation.cpp b/src/analysis/processing/qgsalgorithmextractbylocation.cpp
index c3cd8508f43..419e3e82686 100644
--- a/src/analysis/processing/qgsalgorithmextractbylocation.cpp
+++ b/src/analysis/processing/qgsalgorithmextractbylocation.cpp
@@ -136,7 +136,7 @@ void QgsLocationBasedAlgorithm::process( QgsFeatureSource *targetSource,
 
       if ( !engine )
       {
-        engine.reset( QgsGeometry::createGeometryEngine( f.geometry().geometry() ) );
+        engine.reset( QgsGeometry::createGeometryEngine( f.geometry().constGet() ) );
         engine->prepareGeometry();
       }
 
@@ -146,31 +146,31 @@ void QgsLocationBasedAlgorithm::process( QgsFeatureSource *targetSource,
         switch ( predicate )
         {
           case Intersects:
-            isMatch = engine->intersects( testFeature.geometry().geometry() );
+            isMatch = engine->intersects( testFeature.geometry().constGet() );
             break;
           case Contains:
-            isMatch = engine->contains( testFeature.geometry().geometry() );
+            isMatch = engine->contains( testFeature.geometry().constGet() );
             break;
           case Disjoint:
-            if ( engine->intersects( testFeature.geometry().geometry() ) )
+            if ( engine->intersects( testFeature.geometry().constGet() ) )
             {
               disjointSet.remove( testFeature.id() );
             }
             break;
           case IsEqual:
-            isMatch = engine->isEqual( testFeature.geometry().geometry() );
+            isMatch = engine->isEqual( testFeature.geometry().constGet() );
             break;
           case Touches:
-            isMatch = engine->touches( testFeature.geometry().geometry() );
+            isMatch = engine->touches( testFeature.geometry().constGet() );
             break;
           case Overlaps:
-            isMatch = engine->overlaps( testFeature.geometry().geometry() );
+            isMatch = engine->overlaps( testFeature.geometry().constGet() );
             break;
           case Within:
-            isMatch = engine->within( testFeature.geometry().geometry() );
+            isMatch = engine->within( testFeature.geometry().constGet() );
             break;
           case Crosses:
-            isMatch = engine->crosses( testFeature.geometry().geometry() );
+            isMatch = engine->crosses( testFeature.geometry().constGet() );
             break;
         }
         if ( isMatch )
diff --git a/src/analysis/processing/qgsalgorithmfixgeometries.cpp b/src/analysis/processing/qgsalgorithmfixgeometries.cpp
index 11d5d342bef..290694ab745 100644
--- a/src/analysis/processing/qgsalgorithmfixgeometries.cpp
+++ b/src/analysis/processing/qgsalgorithmfixgeometries.cpp
@@ -83,7 +83,7 @@ QgsFeature QgsFixGeometriesAlgorithm::processFeature( const QgsFeature &feature,
   }
 
   if ( outputGeometry.wkbType() == QgsWkbTypes::Unknown ||
-       QgsWkbTypes::flatType( outputGeometry.geometry()->wkbType() ) == QgsWkbTypes::GeometryCollection )
+       QgsWkbTypes::flatType( outputGeometry.wkbType() ) == QgsWkbTypes::GeometryCollection )
   {
     // keep only the parts of the geometry collection with correct type
     const QList< QgsGeometry > tmpGeometries = outputGeometry.asGeometryCollection();
diff --git a/src/analysis/processing/qgsalgorithmjoinwithlines.cpp b/src/analysis/processing/qgsalgorithmjoinwithlines.cpp
index fbfd74425db..b95abf675a7 100644
--- a/src/analysis/processing/qgsalgorithmjoinwithlines.cpp
+++ b/src/analysis/processing/qgsalgorithmjoinwithlines.cpp
@@ -177,9 +177,9 @@ QVariantMap QgsJoinWithLinesAlgorithm::processAlgorithm( const QVariantMap &para
   {
     QgsPoint p;
     if ( feature.geometry().type() == QgsWkbTypes::PointGeometry && !feature.geometry().isMultipart() )
-      p = *static_cast< QgsPoint *>( feature.geometry().geometry() );
+      p = *static_cast< const QgsPoint *>( feature.geometry().constGet() );
     else
-      p = *static_cast< QgsPoint *>( feature.geometry().pointOnSurface().geometry() );
+      p = *static_cast< const QgsPoint *>( feature.geometry().pointOnSurface().constGet() );
     if ( hasZ && !p.is3D() )
       p.addZValue( 0 );
     if ( hasM && !p.isMeasure() )
diff --git a/src/analysis/processing/qgsalgorithmlineintersection.cpp b/src/analysis/processing/qgsalgorithmlineintersection.cpp
index 086dc461ad2..ebd61b2b1a0 100644
--- a/src/analysis/processing/qgsalgorithmlineintersection.cpp
+++ b/src/analysis/processing/qgsalgorithmlineintersection.cpp
@@ -161,7 +161,7 @@ QVariantMap QgsLineIntersectionAlgorithm::processAlgorithm( const QVariantMap &p
     if ( !lines.empty() )
     {
       // use prepared geometries for faster intersection tests
-      std::unique_ptr< QgsGeometryEngine > engine( QgsGeometry::createGeometryEngine( inGeom.geometry() ) );
+      std::unique_ptr< QgsGeometryEngine > engine( QgsGeometry::createGeometryEngine( inGeom.constGet() ) );
       engine->prepareGeometry();
 
       QgsFeatureRequest request = QgsFeatureRequest().setFilterFids( lines );
@@ -178,7 +178,7 @@ QVariantMap QgsLineIntersectionAlgorithm::processAlgorithm( const QVariantMap &p
         }
 
         QgsGeometry tmpGeom = inFeatureB.geometry();
-        if ( engine->intersects( tmpGeom.geometry() ) )
+        if ( engine->intersects( tmpGeom.constGet() ) )
         {
           QgsMultiPoint points;
           QgsGeometry intersectGeom = inGeom.intersection( tmpGeom );
diff --git a/src/analysis/processing/qgsalgorithmmeancoordinates.cpp b/src/analysis/processing/qgsalgorithmmeancoordinates.cpp
index 62cdc539d19..26fb81b6020 100644
--- a/src/analysis/processing/qgsalgorithmmeancoordinates.cpp
+++ b/src/analysis/processing/qgsalgorithmmeancoordinates.cpp
@@ -164,7 +164,7 @@ QVariantMap QgsMeanCoordinatesAlgorithm::processAlgorithm( const QVariantMap &pa
 
     QgsVertexId vid;
     QgsPoint pt;
-    const QgsAbstractGeometry *g = feat.geometry().geometry();
+    const QgsAbstractGeometry *g = feat.geometry().constGet();
     // NOTE - should this be including the duplicate nodes for closed rings? currently it is,
     // but I suspect that the expected behavior would be to NOT include these
     while ( g->nextVertex( vid, pt ) )
diff --git a/src/analysis/processing/qgsalgorithmsplitwithlines.cpp b/src/analysis/processing/qgsalgorithmsplitwithlines.cpp
index 9510b6fff1c..cbd02163d90 100644
--- a/src/analysis/processing/qgsalgorithmsplitwithlines.cpp
+++ b/src/analysis/processing/qgsalgorithmsplitwithlines.cpp
@@ -140,11 +140,11 @@ QVariantMap QgsSplitWithLinesAlgorithm::processAlgorithm( const QVariantMap &par
         QgsGeometry splitGeom = splitGeoms.value( line );
         if ( !engine )
         {
-          engine.reset( QgsGeometry::createGeometryEngine( inGeom.geometry() ) );
+          engine.reset( QgsGeometry::createGeometryEngine( inGeom.constGet() ) );
           engine->prepareGeometry();
         }
 
-        if ( engine->intersects( splitGeom.geometry() ) )
+        if ( engine->intersects( splitGeom.constGet() ) )
         {
           QList< QgsGeometry > splitGeomParts = splitGeom.asGeometryCollection();
           splittingLines.append( splitGeomParts );
@@ -159,7 +159,7 @@ QVariantMap QgsSplitWithLinesAlgorithm::processAlgorithm( const QVariantMap &par
           QList< QgsGeometry > outGeoms;
 
           // use prepared geometries for faster intersection tests
-          std::unique_ptr< QgsGeometryEngine > splitGeomEngine( QgsGeometry::createGeometryEngine( splitGeom.geometry() ) );
+          std::unique_ptr< QgsGeometryEngine > splitGeomEngine( QgsGeometry::createGeometryEngine( splitGeom.constGet() ) );
           splitGeomEngine->prepareGeometry();
           while ( !inGeoms.empty() )
           {
@@ -172,12 +172,12 @@ QVariantMap QgsSplitWithLinesAlgorithm::processAlgorithm( const QVariantMap &par
             if ( !inGeom )
               continue;
 
-            if ( splitGeomEngine->intersects( inGeom.geometry() ) )
+            if ( splitGeomEngine->intersects( inGeom.constGet() ) )
             {
               QgsGeometry before = inGeom;
               if ( splitterPList.empty() )
               {
-                const QgsCoordinateSequence sequence = splitGeom.geometry()->coordinateSequence();
+                const QgsCoordinateSequence sequence = splitGeom.constGet()->coordinateSequence();
                 for ( const QgsRingSequence &part : sequence )
                 {
                   for ( const QgsPointSequence &ring : part )
@@ -237,12 +237,12 @@ QVariantMap QgsSplitWithLinesAlgorithm::processAlgorithm( const QVariantMap &par
       bool passed = true;
       if ( QgsWkbTypes::geometryType( aGeom.wkbType() ) == QgsWkbTypes::LineGeometry )
       {
-        int numPoints = aGeom.geometry()->nCoordinates();
+        int numPoints = aGeom.constGet()->nCoordinates();
 
         if ( numPoints <= 2 )
         {
           if ( numPoints == 2 )
-            passed = !static_cast< QgsCurve * >( aGeom.geometry() )->isClosed(); // tests if vertex 0 = vertex 1
+            passed = !static_cast< const QgsCurve * >( aGeom.constGet() )->isClosed(); // tests if vertex 0 = vertex 1
           else
             passed = false; // sometimes splitting results in lines of zero length
         }
diff --git a/src/analysis/processing/qgsalgorithmtransect.cpp b/src/analysis/processing/qgsalgorithmtransect.cpp
index f7a7a59c1ad..a38a57553d5 100644
--- a/src/analysis/processing/qgsalgorithmtransect.cpp
+++ b/src/analysis/processing/qgsalgorithmtransect.cpp
@@ -132,7 +132,7 @@ QVariantMap QgsTransectAlgorithm::processAlgorithm( const QVariantMap &parameter
     QgsGeometry inputGeometry = feat.geometry();
 
     inputGeometry.convertToMultiType();
-    const QgsMultiLineString *multiLine = static_cast< QgsMultiLineString *  >( inputGeometry.geometry() );
+    const QgsMultiLineString *multiLine = static_cast< const QgsMultiLineString *  >( inputGeometry.constGet() );
     for ( int id = 0; id < multiLine->numGeometries(); ++id )
     {
       const QgsLineString *line = static_cast< const QgsLineString * >( multiLine->geometryN( id ) );
diff --git a/src/analysis/vector/geometry_checker/qgsfeaturepool.cpp b/src/analysis/vector/geometry_checker/qgsfeaturepool.cpp
index 9b146151302..cd49b2af87f 100644
--- a/src/analysis/vector/geometry_checker/qgsfeaturepool.cpp
+++ b/src/analysis/vector/geometry_checker/qgsfeaturepool.cpp
@@ -109,7 +109,7 @@ void QgsFeaturePool::updateFeature( QgsFeature &feature )
   get( feature.id(), origFeature );
 
   QgsGeometryMap geometryMap;
-  geometryMap.insert( feature.id(), QgsGeometry( feature.geometry().geometry()->clone() ) );
+  geometryMap.insert( feature.id(), QgsGeometry( feature.geometry().constGet()->clone() ) );
   QgsChangedAttributesMap changedAttributesMap;
   QgsAttributeMap attribMap;
   for ( int i = 0, n = feature.attributes().size(); i < n; ++i )
diff --git a/src/analysis/vector/geometry_checker/qgsgeometryanglecheck.cpp b/src/analysis/vector/geometry_checker/qgsgeometryanglecheck.cpp
index fe858f3847b..9dc26e50da0 100644
--- a/src/analysis/vector/geometry_checker/qgsgeometryanglecheck.cpp
+++ b/src/analysis/vector/geometry_checker/qgsgeometryanglecheck.cpp
@@ -73,7 +73,7 @@ void QgsGeometryAngleCheck::fixError( QgsGeometryCheckError *error, int method,
     return;
   }
   QgsGeometry featureGeometry = feature.geometry();
-  QgsAbstractGeometry *geometry = featureGeometry.geometry();
+  QgsAbstractGeometry *geometry = featureGeometry.get();
   QgsVertexId vidx = error->vidx();
 
   // Check if point still exists
diff --git a/src/analysis/vector/geometry_checker/qgsgeometryareacheck.cpp b/src/analysis/vector/geometry_checker/qgsgeometryareacheck.cpp
index d880c68562e..a7275b756a5 100644
--- a/src/analysis/vector/geometry_checker/qgsgeometryareacheck.cpp
+++ b/src/analysis/vector/geometry_checker/qgsgeometryareacheck.cpp
@@ -49,7 +49,7 @@ void QgsGeometryAreaCheck::fixError( QgsGeometryCheckError *error, int method, c
   }
   double layerToMapUnits = featurePool->getLayerToMapUnits();
   QgsGeometry g = feature.geometry();
-  QgsAbstractGeometry *geom = g.geometry();
+  const QgsAbstractGeometry *geom = g.constGet();
   QgsVertexId vidx = error->vidx();
 
   // Check if polygon still exists
@@ -111,7 +111,7 @@ bool QgsGeometryAreaCheck::mergeWithNeighbor( const QString &layerId, QgsFeature
   int mergePartIdx = -1;
   bool matchFound = false;
   QgsGeometry featureGeometry = feature.geometry();
-  QgsAbstractGeometry *geom = featureGeometry.geometry();
+  const QgsAbstractGeometry *geom = featureGeometry.constGet();
 
   // Search for touching neighboring geometries
   for ( QgsFeatureId testId : featurePool->getIntersects( featureGeometry.boundingBox() ) )
@@ -122,7 +122,7 @@ bool QgsGeometryAreaCheck::mergeWithNeighbor( const QString &layerId, QgsFeature
       continue;
     }
     QgsGeometry testFeatureGeom = testFeature.geometry();
-    QgsAbstractGeometry *testGeom = testFeatureGeom.geometry();
+    const QgsAbstractGeometry *testGeom = testFeatureGeom.constGet();
     for ( int testPartIdx = 0, nTestParts = testGeom->partCount(); testPartIdx < nTestParts; ++testPartIdx )
     {
       if ( testId == feature.id() && testPartIdx == partIdx )
@@ -141,8 +141,8 @@ bool QgsGeometryAreaCheck::mergeWithNeighbor( const QString &layerId, QgsFeature
           }
           else
           {
-            if ( dynamic_cast<QgsGeometryCollection *>( testGeom ) )
-              val = static_cast<QgsGeometryCollection *>( testGeom )->geometryN( testPartIdx )->area();
+            if ( dynamic_cast<const QgsGeometryCollection *>( testGeom ) )
+              val = static_cast<const QgsGeometryCollection *>( testGeom )->geometryN( testPartIdx )->area();
             else
               val = testGeom->area();
           }
@@ -178,7 +178,7 @@ bool QgsGeometryAreaCheck::mergeWithNeighbor( const QString &layerId, QgsFeature
 
   // Merge geometries
   QgsGeometry mergeFeatureGeom = mergeFeature.geometry();
-  QgsAbstractGeometry *mergeGeom = mergeFeatureGeom.geometry();
+  const QgsAbstractGeometry *mergeGeom = mergeFeatureGeom.constGet();
   QSharedPointer<QgsGeometryEngine> geomEngine = QgsGeometryCheckerUtils::createGeomEngine( QgsGeometryCheckerUtils::getGeomPart( mergeGeom, mergePartIdx ), mContext->reducedTolerance );
   QgsAbstractGeometry *combinedGeom = geomEngine->combine( QgsGeometryCheckerUtils::getGeomPart( geom, partIdx ), &errMsg );
   if ( !combinedGeom || combinedGeom->isEmpty() || !QgsWkbTypes::isSingleType( combinedGeom->wkbType() ) )
diff --git a/src/analysis/vector/geometry_checker/qgsgeometrycheck.cpp b/src/analysis/vector/geometry_checker/qgsgeometrycheck.cpp
index c7b2c8bdcf3..5168206be07 100644
--- a/src/analysis/vector/geometry_checker/qgsgeometrycheck.cpp
+++ b/src/analysis/vector/geometry_checker/qgsgeometrycheck.cpp
@@ -157,10 +157,9 @@ void QgsGeometryCheck::replaceFeatureGeometryPart( const QString &layerId, QgsFe
 {
   QgsFeaturePool *featurePool = mContext->featurePools[layerId];
   QgsGeometry featureGeom = feature.geometry();
-  QgsAbstractGeometry *geom = featureGeom.geometry();
-  if ( dynamic_cast<QgsGeometryCollection *>( geom ) )
+  QgsAbstractGeometry *geom = featureGeom.get();
+  if ( QgsGeometryCollection *geomCollection = dynamic_cast< QgsGeometryCollection *>( geom ) )
   {
-    QgsGeometryCollection *geomCollection = static_cast<QgsGeometryCollection *>( geom );
     geomCollection->removeGeometry( partIdx );
     geomCollection->addGeometry( newPartGeom );
     changes[layerId][feature.id()].append( Change( ChangePart, ChangeRemoved, QgsVertexId( partIdx ) ) );
@@ -179,7 +178,7 @@ void QgsGeometryCheck::deleteFeatureGeometryPart( const QString &layerId, QgsFea
 {
   QgsFeaturePool *featurePool = mContext->featurePools[layerId];
   QgsGeometry featureGeom = feature.geometry();
-  QgsAbstractGeometry *geom = featureGeom.geometry();
+  QgsAbstractGeometry *geom = featureGeom.get();
   if ( dynamic_cast<QgsGeometryCollection *>( geom ) )
   {
     static_cast<QgsGeometryCollection *>( geom )->removeGeometry( partIdx );
@@ -206,7 +205,7 @@ void QgsGeometryCheck::deleteFeatureGeometryRing( const QString &layerId, QgsFea
 {
   QgsFeaturePool *featurePool = mContext->featurePools[layerId];
   QgsGeometry featureGeom = feature.geometry();
-  QgsAbstractGeometry *partGeom = QgsGeometryCheckerUtils::getGeomPart( featureGeom.geometry(), partIdx );
+  QgsAbstractGeometry *partGeom = QgsGeometryCheckerUtils::getGeomPart( featureGeom.get(), partIdx );
   if ( dynamic_cast<QgsCurvePolygon *>( partGeom ) )
   {
     // If we delete the exterior ring of a polygon, it makes no sense to keep the interiors
diff --git a/src/analysis/vector/geometry_checker/qgsgeometrycheckerutils.cpp b/src/analysis/vector/geometry_checker/qgsgeometrycheckerutils.cpp
index a77c2e012db..103338a7f51 100644
--- a/src/analysis/vector/geometry_checker/qgsgeometrycheckerutils.cpp
+++ b/src/analysis/vector/geometry_checker/qgsgeometrycheckerutils.cpp
@@ -31,7 +31,7 @@ namespace QgsGeometryCheckerUtils
     , mFeature( feature )
     , mMapCrs( useMapCrs )
   {
-    mGeometry = feature.geometry().geometry()->clone();
+    mGeometry = feature.geometry().constGet()->clone();
     if ( useMapCrs && !mFeaturePool->getLayerToMapTransform().isShortCircuited() )
     {
       mGeometry->transform( mFeaturePool->getLayerToMapTransform() );
@@ -124,7 +124,7 @@ namespace QgsGeometryCheckerUtils
       if ( mParent->mProgressCounter )
         mParent->mProgressCounter->fetchAndAddRelaxed( 1 );
       QgsFeature feature;
-      if ( featurePool->get( *mFeatureIt, feature ) && feature.geometry() && feature.geometry().geometry() )
+      if ( featurePool->get( *mFeatureIt, feature ) && feature.geometry() && feature.geometry().constGet() )
       {
         delete mCurrentFeature;
         mCurrentFeature = new LayerFeature( mParent->mFeaturePools[*mLayerIt], feature, mParent->mUseMapCrs );
diff --git a/src/analysis/vector/geometry_checker/qgsgeometrydegeneratepolygoncheck.cpp b/src/analysis/vector/geometry_checker/qgsgeometrydegeneratepolygoncheck.cpp
index 0dc60883dc2..7e84ceaee4e 100644
--- a/src/analysis/vector/geometry_checker/qgsgeometrydegeneratepolygoncheck.cpp
+++ b/src/analysis/vector/geometry_checker/qgsgeometrydegeneratepolygoncheck.cpp
@@ -47,7 +47,7 @@ void QgsGeometryDegeneratePolygonCheck::fixError( QgsGeometryCheckError *error,
     return;
   }
   QgsGeometry featureGeometry = feature.geometry();
-  QgsAbstractGeometry *geom = featureGeometry.geometry();
+  const QgsAbstractGeometry *geom = featureGeometry.constGet();
   QgsVertexId vidx = error->vidx();
 
   // Check if ring still exists
diff --git a/src/analysis/vector/geometry_checker/qgsgeometryduplicatenodescheck.cpp b/src/analysis/vector/geometry_checker/qgsgeometryduplicatenodescheck.cpp
index 8b6f8cf23d1..2511ebac38c 100644
--- a/src/analysis/vector/geometry_checker/qgsgeometryduplicatenodescheck.cpp
+++ b/src/analysis/vector/geometry_checker/qgsgeometryduplicatenodescheck.cpp
@@ -55,7 +55,7 @@ void QgsGeometryDuplicateNodesCheck::fixError( QgsGeometryCheckError *error, int
     return;
   }
   QgsGeometry featureGeom = feature.geometry();
-  QgsAbstractGeometry *geom = featureGeom.geometry();
+  QgsAbstractGeometry *geom = featureGeom.get();
   QgsVertexId vidx = error->vidx();
 
   // Check if point still exists
diff --git a/src/analysis/vector/geometry_checker/qgsgeometryfollowboundariescheck.cpp b/src/analysis/vector/geometry_checker/qgsgeometryfollowboundariescheck.cpp
index 18c411fe777..3a39fcef41f 100644
--- a/src/analysis/vector/geometry_checker/qgsgeometryfollowboundariescheck.cpp
+++ b/src/analysis/vector/geometry_checker/qgsgeometryfollowboundariescheck.cpp
@@ -74,7 +74,7 @@ void QgsGeometryFollowBoundariesCheck::collectErrors( QList<QgsGeometryCheckErro
       QgsFeature refFeature;
       while ( refFeatureIt.nextFeature( refFeature ) )
       {
-        QgsAbstractGeometry *refGeom = refFeature.geometry().geometry();
+        const QgsAbstractGeometry *refGeom = refFeature.geometry().constGet();
         QSharedPointer<QgsGeometryEngine> refgeomEngine = QgsGeometryCheckerUtils::createGeomEngine( refGeom, mContext->tolerance );
         QScopedPointer<QgsAbstractGeometry> reducedRefGeom( refgeomEngine->buffer( -mContext->tolerance, 0 ) );
         if ( !( geomEngine->contains( reducedRefGeom.data() ) || geomEngine->disjoint( reducedRefGeom.data() ) ) )
diff --git a/src/analysis/vector/geometry_checker/qgsgeometrygapcheck.cpp b/src/analysis/vector/geometry_checker/qgsgeometrygapcheck.cpp
index 66a063d30bc..24f95a80e85 100644
--- a/src/analysis/vector/geometry_checker/qgsgeometrygapcheck.cpp
+++ b/src/analysis/vector/geometry_checker/qgsgeometrygapcheck.cpp
@@ -168,7 +168,7 @@ bool QgsGeometryGapCheck::mergeWithNeighbor( QgsGeometryGapCheckError *err, Chan
         continue;
       }
       QgsGeometry featureGeom = testFeature.geometry();
-      QgsAbstractGeometry *testGeom = featureGeom.geometry();
+      const QgsAbstractGeometry *testGeom = featureGeom.constGet();
       for ( int iPart = 0, nParts = testGeom->partCount(); iPart < nParts; ++iPart )
       {
         double len = QgsGeometryCheckerUtils::sharedEdgeLength( errLayerGeom, QgsGeometryCheckerUtils::getGeomPart( testGeom, iPart ), mContext->reducedTolerance );
@@ -194,7 +194,7 @@ bool QgsGeometryGapCheck::mergeWithNeighbor( QgsGeometryGapCheckError *err, Chan
   QgsAbstractGeometry *errLayerGeom = errGeometry->clone();
   errLayerGeom->transform( featurePool->getLayerToMapTransform(), QgsCoordinateTransform::ReverseTransform );
   QgsGeometry mergeFeatureGeom = mergeFeature.geometry();
-  QgsAbstractGeometry *mergeGeom = mergeFeatureGeom.geometry();
+  const QgsAbstractGeometry *mergeGeom = mergeFeatureGeom.constGet();
   QSharedPointer<QgsGeometryEngine> geomEngine = QgsGeometryCheckerUtils::createGeomEngine( errLayerGeom, mContext->reducedTolerance );
   QgsAbstractGeometry *combinedGeom = geomEngine->combine( QgsGeometryCheckerUtils::getGeomPart( mergeGeom, mergePartIdx ), &errMsg );
   delete errLayerGeom;
diff --git a/src/analysis/vector/geometry_checker/qgsgeometryholecheck.cpp b/src/analysis/vector/geometry_checker/qgsgeometryholecheck.cpp
index 4b7338fd173..c4d599ad155 100644
--- a/src/analysis/vector/geometry_checker/qgsgeometryholecheck.cpp
+++ b/src/analysis/vector/geometry_checker/qgsgeometryholecheck.cpp
@@ -53,7 +53,7 @@ void QgsGeometryHoleCheck::fixError( QgsGeometryCheckError *error, int method, c
     return;
   }
   QgsGeometry featureGeom = feature.geometry();
-  QgsAbstractGeometry *geom = featureGeom.geometry();
+  const QgsAbstractGeometry *geom = featureGeom.constGet();
   QgsVertexId vidx = error->vidx();
 
   // Check if ring still exists
diff --git a/src/analysis/vector/geometry_checker/qgsgeometrymultipartcheck.cpp b/src/analysis/vector/geometry_checker/qgsgeometrymultipartcheck.cpp
index 58f3999b3b2..e1a480f7163 100644
--- a/src/analysis/vector/geometry_checker/qgsgeometrymultipartcheck.cpp
+++ b/src/analysis/vector/geometry_checker/qgsgeometrymultipartcheck.cpp
@@ -41,7 +41,7 @@ void QgsGeometryMultipartCheck::fixError( QgsGeometryCheckError *error, int meth
     return;
   }
   QgsGeometry featureGeom = feature.geometry();
-  QgsAbstractGeometry *geom = featureGeom.geometry();
+  const QgsAbstractGeometry *geom = featureGeom.constGet();
 
   // Check if error still applies
   if ( geom->partCount() > 1 || !QgsWkbTypes::isMultiType( geom->wkbType() ) )
diff --git a/src/analysis/vector/geometry_checker/qgsgeometrysegmentlengthcheck.cpp b/src/analysis/vector/geometry_checker/qgsgeometrysegmentlengthcheck.cpp
index 6e1f508bb31..a8ccf8781e9 100644
--- a/src/analysis/vector/geometry_checker/qgsgeometrysegmentlengthcheck.cpp
+++ b/src/analysis/vector/geometry_checker/qgsgeometrysegmentlengthcheck.cpp
@@ -65,7 +65,7 @@ void QgsGeometrySegmentLengthCheck::fixError( QgsGeometryCheckError *error, int
   }
 
   QgsGeometry featureGeom = feature.geometry();
-  QgsAbstractGeometry *geom = featureGeom.geometry();
+  const QgsAbstractGeometry *geom = featureGeom.constGet();
   QgsVertexId vidx = error->vidx();
 
   // Check if point still exists
diff --git a/src/analysis/vector/geometry_checker/qgsgeometryselfintersectioncheck.cpp b/src/analysis/vector/geometry_checker/qgsgeometryselfintersectioncheck.cpp
index 9aefcf925cf..e676ec51b8e 100644
--- a/src/analysis/vector/geometry_checker/qgsgeometryselfintersectioncheck.cpp
+++ b/src/analysis/vector/geometry_checker/qgsgeometryselfintersectioncheck.cpp
@@ -90,7 +90,7 @@ void QgsGeometrySelfIntersectionCheck::fixError( QgsGeometryCheckError *error, i
     return;
   }
   QgsGeometry featureGeom = feature.geometry();
-  QgsAbstractGeometry *geom = featureGeom.geometry();
+  QgsAbstractGeometry *geom = featureGeom.get();
   QgsVertexId vidx = error->vidx();
 
   // Check if ring still exists
diff --git a/src/analysis/vector/geometry_checker/qgsgeometrytypecheck.cpp b/src/analysis/vector/geometry_checker/qgsgeometrytypecheck.cpp
index 33fa23789c2..a03cf0a9f9d 100644
--- a/src/analysis/vector/geometry_checker/qgsgeometrytypecheck.cpp
+++ b/src/analysis/vector/geometry_checker/qgsgeometrytypecheck.cpp
@@ -48,7 +48,7 @@ void QgsGeometryTypeCheck::fixError( QgsGeometryCheckError *error, int method, c
     return;
   }
   QgsGeometry featureGeom = feature.geometry();
-  QgsAbstractGeometry *geom = featureGeom.geometry();
+  const QgsAbstractGeometry *geom = featureGeom.constGet();
 
   // Check if error still applies
   QgsWkbTypes::Type type = QgsWkbTypes::flatType( geom->wkbType() );
diff --git a/src/analysis/vector/qgsgeometrysnapper.cpp b/src/analysis/vector/qgsgeometrysnapper.cpp
index 778c8d0af31..7a0b3050140 100644
--- a/src/analysis/vector/qgsgeometrysnapper.cpp
+++ b/src/analysis/vector/qgsgeometrysnapper.cpp
@@ -505,17 +505,17 @@ QgsGeometry QgsGeometrySnapper::snapGeometry( const QgsGeometry &geometry, doubl
        ( mode == EndPointPreferClosest || mode == EndPointPreferNodes || mode == EndPointToEndPoint ) )
     return geometry;
 
-  QgsPoint center = qgsgeometry_cast< const QgsPoint * >( geometry.geometry() ) ? *static_cast< const QgsPoint * >( geometry.geometry() ) :
-                    QgsPoint( geometry.geometry()->boundingBox().center() );
+  QgsPoint center = qgsgeometry_cast< const QgsPoint * >( geometry.constGet() ) ? *static_cast< const QgsPoint * >( geometry.constGet() ) :
+                    QgsPoint( geometry.constGet()->boundingBox().center() );
 
   QgsSnapIndex refSnapIndex( center, 10 * snapTolerance );
   Q_FOREACH ( const QgsGeometry &geom, referenceGeometries )
   {
-    refSnapIndex.addGeometry( geom.geometry() );
+    refSnapIndex.addGeometry( geom.constGet() );
   }
 
   // Snap geometries
-  QgsAbstractGeometry *subjGeom = geometry.geometry()->clone();
+  QgsAbstractGeometry *subjGeom = geometry.constGet()->clone();
   QList < QList< QList<PointFlag> > > subjPointFlags;
 
   // Pass 1: snap vertices of subject geometry to reference vertices
@@ -619,16 +619,16 @@ QgsGeometry QgsGeometrySnapper::snapGeometry( const QgsGeometry &geometry, doubl
   // Pass 2: add missing vertices to subject geometry
   Q_FOREACH ( const QgsGeometry &refGeom, referenceGeometries )
   {
-    for ( int iPart = 0, nParts = refGeom.geometry()->partCount(); iPart < nParts; ++iPart )
+    for ( int iPart = 0, nParts = refGeom.constGet()->partCount(); iPart < nParts; ++iPart )
     {
-      for ( int iRing = 0, nRings = refGeom.geometry()->ringCount( iPart ); iRing < nRings; ++iRing )
+      for ( int iRing = 0, nRings = refGeom.constGet()->ringCount( iPart ); iRing < nRings; ++iRing )
       {
-        for ( int iVert = 0, nVerts = polyLineSize( refGeom.geometry(), iPart, iRing ); iVert < nVerts; ++iVert )
+        for ( int iVert = 0, nVerts = polyLineSize( refGeom.constGet(), iPart, iRing ); iVert < nVerts; ++iVert )
         {
 
           QgsSnapIndex::PointSnapItem *snapPoint = nullptr;
           QgsSnapIndex::SegmentSnapItem *snapSegment = nullptr;
-          QgsPoint point = refGeom.geometry()->vertexAt( QgsVertexId( iPart, iRing, iVert ) );
+          QgsPoint point = refGeom.constGet()->vertexAt( QgsVertexId( iPart, iRing, iVert ) );
           if ( subjSnapIndex->getSnapItem( point, snapTolerance, &snapPoint, &snapSegment ) )
           {
             // Snap to segment, unless a subject point was already snapped to the reference point
diff --git a/src/app/dwg/qgsdwgimporter.cpp b/src/app/dwg/qgsdwgimporter.cpp
index 21a848d5c5e..1802050c63d 100644
--- a/src/app/dwg/qgsdwgimporter.cpp
+++ b/src/app/dwg/qgsdwgimporter.cpp
@@ -2672,7 +2672,7 @@ bool QgsDwgImporter::expandInserts( QString &error )
           continue;
         }
 
-        QByteArray wkb = g.geometry()->asWkb();
+        QByteArray wkb = g.constGet()->asWkb();
         if ( OGR_G_CreateFromWkb( ( unsigned char * ) wkb.constData(), nullptr, &ogrG, wkb.size() ) != OGRERR_NONE )
         {
           QgsDebugMsg( QString( "%1/%2: could not create ogr geometry" ).arg( name ).arg( fid ) );
diff --git a/src/app/nodetool/qgsnodetool.cpp b/src/app/nodetool/qgsnodetool.cpp
index 5cc81b3b1dc..09f3dab9552 100644
--- a/src/app/nodetool/qgsnodetool.cpp
+++ b/src/app/nodetool/qgsnodetool.cpp
@@ -54,12 +54,12 @@ uint qHash( const Vertex &v )
 //! Find out whether vertex at the given index is an endpoint (assuming linear geometry)
 static bool isEndpointAtVertexIndex( const QgsGeometry &geom, int vertexIndex )
 {
-  QgsAbstractGeometry *g = geom.geometry();
-  if ( QgsCurve *curve = dynamic_cast<QgsCurve *>( g ) )
+  const QgsAbstractGeometry *g = geom.constGet();
+  if ( const QgsCurve *curve = qgsgeometry_cast< const QgsCurve *>( g ) )
   {
     return vertexIndex == 0 || vertexIndex == curve->numPoints() - 1;
   }
-  else if ( QgsMultiCurve *multiCurve = dynamic_cast<QgsMultiCurve *>( g ) )
+  else if ( const QgsMultiCurve *multiCurve = qgsgeometry_cast<const QgsMultiCurve *>( g ) )
   {
     for ( int i = 0; i < multiCurve->numGeometries(); ++i )
     {
@@ -83,17 +83,17 @@ static bool isEndpointAtVertexIndex( const QgsGeometry &geom, int vertexIndex )
 //! Return index of vertex adjacent to the given endpoint. Assuming linear geometries.
 int adjacentVertexIndexToEndpoint( const QgsGeometry &geom, int vertexIndex )
 {
-  QgsAbstractGeometry *g = geom.geometry();
-  if ( QgsCurve *curve = dynamic_cast<QgsCurve *>( g ) )
+  const QgsAbstractGeometry *g = geom.constGet();
+  if ( const QgsCurve *curve = qgsgeometry_cast<const QgsCurve *>( g ) )
   {
     return vertexIndex == 0 ? 1 : curve->numPoints() - 2;
   }
-  else if ( QgsMultiCurve *multiCurve = dynamic_cast<QgsMultiCurve *>( g ) )
+  else if ( const QgsMultiCurve *multiCurve = qgsgeometry_cast<const QgsMultiCurve *>( g ) )
   {
     int offset = 0;
     for ( int i = 0; i < multiCurve->numGeometries(); ++i )
     {
-      QgsCurve *part = qgsgeometry_cast<QgsCurve *>( multiCurve->geometryN( i ) );
+      const QgsCurve *part = qgsgeometry_cast<const QgsCurve *>( multiCurve->geometryN( i ) );
       Q_ASSERT( part );
       if ( vertexIndex < part->numPoints() )
         return vertexIndex == 0 ? offset + 1 : offset + part->numPoints() - 2;
@@ -125,7 +125,7 @@ static QgsGeometry geometryToMultiPoint( const QgsGeometry &geom )
 {
   QgsMultiPointV2 *multiPoint = new QgsMultiPointV2();
   QgsGeometry outputGeom( multiPoint );
-  QgsAbstractGeometry *g = geom.geometry();
+  const QgsAbstractGeometry *g = geom.constGet();
   for ( int i = 0; i < g->partCount(); ++i )
     for ( int j = 0; j < g->ringCount( i ); ++j )
       for ( int k = 0; k < g->vertexCount( i, j ); ++k )
@@ -180,7 +180,7 @@ class MatchCollectingFilter : public QgsPointLocator::MatchFilter
       QgsGeometry matchGeom = nodetool->cachedGeometry( match.layer(), match.featureId() );
       QgsVertexId vid;
       QgsPoint pt;
-      while ( matchGeom.geometry()->nextVertex( vid, pt ) )
+      while ( matchGeom.constGet()->nextVertex( vid, pt ) )
       {
         int vindex = matchGeom.vertexNrFromVertexId( vid );
         if ( pt.x() == match.point().x() && pt.y() == match.point().y() && vindex != match.vertexIndex() )
@@ -435,7 +435,7 @@ void QgsNodeTool::cadCanvasReleaseEvent( QgsMapMouseEvent *e )
       while ( fi.nextFeature( f ) )
       {
         QgsGeometry g = f.geometry();
-        for ( int i = 0; i < g.geometry()->nCoordinates(); ++i )
+        for ( int i = 0; i < g.constGet()->nCoordinates(); ++i )
         {
           QgsPointXY pt = g.vertexAt( i );
           if ( layerRect.contains( pt ) )
@@ -828,8 +828,8 @@ void QgsNodeTool::mouseMoveNotDragging( QgsMapMouseEvent *e )
     QgsGeometry geom = cachedGeometry( m.layer(), m.featureId() );
     mFeatureBandMarkers->setToGeometry( geometryToMultiPoint( geom ), m.layer() );
     mFeatureBandMarkers->setVisible( true );
-    if ( QgsWkbTypes::isCurvedType( geom.geometry()->wkbType() ) )
-      geom = QgsGeometry( geom.geometry()->segmentize() );
+    if ( QgsWkbTypes::isCurvedType( geom.wkbType() ) )
+      geom = QgsGeometry( geom.constGet()->segmentize() );
     mFeatureBand->setToGeometry( geom, m.layer() );
     mFeatureBand->setVisible( true );
     mFeatureBandLayer = m.layer();
@@ -994,7 +994,7 @@ void QgsNodeTool::deleteNodeEditorSelection()
     if ( mSelectedFeature->geometry()->type() == QgsWkbTypes::LineGeometry )
     {
       // for lines we don't wrap around vertex selection when deleting nodes from end of line
-      nextVertexToSelect = std::min( nextVertexToSelect, mSelectedFeature->geometry()->geometry()->nCoordinates() - 1 );
+      nextVertexToSelect = std::min( nextVertexToSelect, mSelectedFeature->geometry()->constGet()->nCoordinates() - 1 );
     }
 
     _safeSelectVertex( *mSelectedFeature, nextVertexToSelect );
@@ -1398,7 +1398,7 @@ void QgsNodeTool::moveVertex( const QgsPointXY &mapPoint, const QgsPointLocator:
     return;
   }
 
-  QgsAbstractGeometry *geomTmp = geom.geometry()->clone();
+  QgsAbstractGeometry *geomTmp = geom.constGet()->clone();
 
   // add/move vertex
   if ( addingVertex )
@@ -1425,7 +1425,7 @@ void QgsNodeTool::moveVertex( const QgsPointXY &mapPoint, const QgsPointLocator:
     }
   }
 
-  geom.setGeometry( geomTmp );
+  geom.set( geomTmp );
 
   NodeEdits edits; // dict { layer : { fid : geom } }
   edits[dragLayer][dragFid] = geom;
@@ -1582,7 +1582,7 @@ void QgsNodeTool::deleteVertex()
           QgsVertexId vid;
           if ( geom.vertexIdFromVertexNr( vertexIds[i], vid ) )
           {
-            int ringVertexCount = geom.geometry()->vertexCount( vid.part, vid.ring );
+            int ringVertexCount = geom.constGet()->vertexCount( vid.part, vid.ring );
             if ( vid.vertex == ringVertexCount - 1 )
             {
               // this is the last vertex of the ring - remove the first vertex from the list
diff --git a/src/app/nodetool/qgsselectedfeature.cpp b/src/app/nodetool/qgsselectedfeature.cpp
index 29801222ca2..50467552b33 100644
--- a/src/app/nodetool/qgsselectedfeature.cpp
+++ b/src/app/nodetool/qgsselectedfeature.cpp
@@ -274,7 +274,7 @@ void QgsSelectedFeature::createVertexMap()
     return;
   }
 
-  const QgsAbstractGeometry *geom = mGeometry->geometry();
+  const QgsAbstractGeometry *geom = mGeometry->constGet();
   if ( !geom )
   {
     return;
diff --git a/src/app/qgsmaptooladdpart.cpp b/src/app/qgsmaptooladdpart.cpp
index 9fe9b30c0b6..28e536b5b06 100644
--- a/src/app/qgsmaptooladdpart.cpp
+++ b/src/app/qgsmaptooladdpart.cpp
@@ -154,7 +154,7 @@ void QgsMapToolAddPart::cadCanvasReleaseEvent( QgsMapMouseEvent *e )
         QgsGeometry *geom = new QgsGeometry( cp );
         geom->avoidIntersections( QgsProject::instance()->avoidIntersectionsLayers() );
 
-        const QgsCurvePolygon *cpGeom = qgsgeometry_cast<const QgsCurvePolygon *>( geom->geometry() );
+        const QgsCurvePolygon *cpGeom = qgsgeometry_cast<const QgsCurvePolygon *>( geom->constGet() );
         if ( !cpGeom )
         {
           stopCapturing();
diff --git a/src/app/qgsselectbyformdialog.cpp b/src/app/qgsselectbyformdialog.cpp
index f2c99ca46a6..3cdb2b58b87 100644
--- a/src/app/qgsselectbyformdialog.cpp
+++ b/src/app/qgsselectbyformdialog.cpp
@@ -83,7 +83,7 @@ void QgsSelectByFormDialog::zoomToFeatures( const QString &filter )
   while ( features.nextFeature( feat ) )
   {
     QgsGeometry geom = feat.geometry();
-    if ( geom.isNull() || geom.geometry()->isEmpty() )
+    if ( geom.isNull() || geom.constGet()->isEmpty() )
       continue;
 
     QgsRectangle r = mMapCanvas->mapSettings().layerExtentToOutputExtent( mLayer, geom.boundingBox() );
diff --git a/src/core/dxf/qgsdxfexport.cpp b/src/core/dxf/qgsdxfexport.cpp
index 906fe714510..565ee6bff73 100644
--- a/src/core/dxf/qgsdxfexport.cpp
+++ b/src/core/dxf/qgsdxfexport.cpp
@@ -3677,7 +3677,7 @@ void QgsDxfExport::addFeature( QgsSymbolRenderContext &ctx, const QgsCoordinateT
   if ( !fet->hasGeometry() )
     return;
 
-  std::unique_ptr<QgsAbstractGeometry> geom( fet->geometry().geometry()->clone() );
+  std::unique_ptr<QgsAbstractGeometry> geom( fet->geometry().constGet()->clone() );
   if ( ct.isValid() )
   {
     geom->transform( ct );
diff --git a/src/core/expression/qgsexpression.cpp b/src/core/expression/qgsexpression.cpp
index 0e0a7dfdc49..dbb430a5582 100644
--- a/src/core/expression/qgsexpression.cpp
+++ b/src/core/expression/qgsexpression.cpp
@@ -780,7 +780,7 @@ QString QgsExpression::formatPreviewString( const QVariant &value )
     if ( geom.isNull() )
       return tr( "<i>&lt;empty geometry&gt;</i>" );
     else
-      return tr( "<i>&lt;geometry: %1&gt;</i>" ).arg( QgsWkbTypes::displayString( geom.geometry()->wkbType() ) );
+      return tr( "<i>&lt;geometry: %1&gt;</i>" ).arg( QgsWkbTypes::displayString( geom.constGet()->wkbType() ) );
   }
   else if ( !value.isValid() )
   {
diff --git a/src/core/expression/qgsexpressionfunction.cpp b/src/core/expression/qgsexpressionfunction.cpp
index 97ba905bd45..6843bb3aca4 100644
--- a/src/core/expression/qgsexpressionfunction.cpp
+++ b/src/core/expression/qgsexpressionfunction.cpp
@@ -1632,7 +1632,7 @@ static QVariant fcnGeomZ( const QVariantList &values, const QgsExpressionContext
   //if single point, return the point's z coordinate
   if ( geom.type() == QgsWkbTypes::PointGeometry && !geom.isMultipart() )
   {
-    QgsPoint *point = qgsgeometry_cast< QgsPoint * >( geom.geometry() );
+    const QgsPoint *point = qgsgeometry_cast< const QgsPoint * >( geom.constGet() );
     if ( point )
       return point->z();
   }
@@ -1649,7 +1649,7 @@ static QVariant fcnGeomM( const QVariantList &values, const QgsExpressionContext
   //if single point, return the point's m value
   if ( geom.type() == QgsWkbTypes::PointGeometry && !geom.isMultipart() )
   {
-    QgsPoint *point = qgsgeometry_cast< QgsPoint * >( geom.geometry() );
+    const QgsPoint *point = qgsgeometry_cast< const QgsPoint * >( geom.constGet() );
     if ( point )
       return point->m();
   }
@@ -1674,7 +1674,7 @@ static QVariant fcnPointN( const QVariantList &values, const QgsExpressionContex
     return QVariant();
   }
 
-  QgsPoint point = geom.geometry()->vertexAt( vId );
+  QgsPoint point = geom.constGet()->vertexAt( vId );
   return QVariant::fromValue( QgsGeometry( new QgsPoint( point ) ) );
 }
 
@@ -1691,7 +1691,7 @@ static QVariant fcnStartPoint( const QVariantList &values, const QgsExpressionCo
     return QVariant();
   }
 
-  QgsPoint point = geom.geometry()->vertexAt( vId );
+  QgsPoint point = geom.constGet()->vertexAt( vId );
   return QVariant::fromValue( QgsGeometry( new QgsPoint( point ) ) );
 }
 
@@ -1703,12 +1703,12 @@ static QVariant fcnEndPoint( const QVariantList &values, const QgsExpressionCont
     return QVariant();
 
   QgsVertexId vId;
-  if ( !geom.vertexIdFromVertexNr( geom.geometry()->nCoordinates() - 1, vId ) )
+  if ( !geom.vertexIdFromVertexNr( geom.constGet()->nCoordinates() - 1, vId ) )
   {
     return QVariant();
   }
 
-  QgsPoint point = geom.geometry()->vertexAt( vId );
+  QgsPoint point = geom.constGet()->vertexAt( vId );
   return QVariant::fromValue( QgsGeometry( new QgsPoint( point ) ) );
 }
 
@@ -1727,7 +1727,7 @@ static QVariant fcnNodesToPoints( const QVariantList &values, const QgsExpressio
 
   QgsMultiPointV2 *mp = new QgsMultiPointV2();
 
-  const QgsCoordinateSequence sequence = geom.geometry()->coordinateSequence();
+  const QgsCoordinateSequence sequence = geom.constGet()->coordinateSequence();
   for ( const QgsRingSequence &part : sequence )
   {
     for ( const QgsPointSequence &ring : part )
@@ -1755,7 +1755,7 @@ static QVariant fcnSegmentsToLines( const QVariantList &values, const QgsExpress
   if ( geom.isNull() )
     return QVariant();
 
-  const QList< QgsLineString * > linesToProcess = QgsGeometryUtils::extractLineStrings( geom.geometry() );
+  const QList< QgsLineString * > linesToProcess = QgsGeometryUtils::extractLineStrings( geom.constGet() );
 
   //OK, now we have a complete list of segmentized lines from the geometry
   QgsMultiLineString *ml = new QgsMultiLineString();
@@ -1782,7 +1782,7 @@ static QVariant fcnInteriorRingN( const QVariantList &values, const QgsExpressio
   if ( geom.isNull() )
     return QVariant();
 
-  QgsCurvePolygon *curvePolygon = qgsgeometry_cast< QgsCurvePolygon * >( geom.geometry() );
+  const QgsCurvePolygon *curvePolygon = qgsgeometry_cast< const QgsCurvePolygon * >( geom.constGet() );
   if ( !curvePolygon )
     return QVariant();
 
@@ -1804,7 +1804,7 @@ static QVariant fcnGeometryN( const QVariantList &values, const QgsExpressionCon
   if ( geom.isNull() )
     return QVariant();
 
-  QgsGeometryCollection *collection = qgsgeometry_cast< QgsGeometryCollection * >( geom.geometry() );
+  const QgsGeometryCollection *collection = qgsgeometry_cast< const QgsGeometryCollection * >( geom.constGet() );
   if ( !collection )
     return QVariant();
 
@@ -1826,7 +1826,7 @@ static QVariant fcnBoundary( const QVariantList &values, const QgsExpressionCont
   if ( geom.isNull() )
     return QVariant();
 
-  QgsAbstractGeometry *boundary = geom.geometry()->boundary();
+  QgsAbstractGeometry *boundary = geom.constGet()->boundary();
   if ( !boundary )
     return QVariant();
 
@@ -1951,7 +1951,7 @@ static QVariant fcnMakeLine( const QVariantList &values, const QgsExpressionCont
     if ( geom.type() != QgsWkbTypes::PointGeometry || geom.isMultipart() )
       continue;
 
-    QgsPoint *point = qgsgeometry_cast< QgsPoint * >( geom.geometry() );
+    const QgsPoint *point = qgsgeometry_cast< const QgsPoint * >( geom.constGet() );
     if ( !point )
       continue;
 
@@ -1974,7 +1974,7 @@ static QVariant fcnMakePolygon( const QVariantList &values, const QgsExpressionC
     return QVariant();
 
   QgsPolygonV2 *polygon = new QgsPolygonV2();
-  polygon->setExteriorRing( qgsgeometry_cast< QgsCurve * >( outerRing.geometry()->clone() ) );
+  polygon->setExteriorRing( qgsgeometry_cast< QgsCurve * >( outerRing.constGet()->clone() ) );
 
   for ( int i = 1; i < values.count(); ++i )
   {
@@ -1985,7 +1985,7 @@ static QVariant fcnMakePolygon( const QVariantList &values, const QgsExpressionC
     if ( ringGeom.type() != QgsWkbTypes::LineGeometry || ringGeom.isMultipart() || ringGeom.isNull() )
       continue;
 
-    polygon->addInteriorRing( qgsgeometry_cast< QgsCurve * >( ringGeom.geometry()->clone() ) );
+    polygon->addInteriorRing( qgsgeometry_cast< QgsCurve * >( ringGeom.constGet()->clone() ) );
   }
 
   return QVariant::fromValue( QgsGeometry( polygon ) );
@@ -2006,7 +2006,7 @@ static QVariant fcnMakeTriangle( const QVariantList &values, const QgsExpression
     if ( geom.type() != QgsWkbTypes::PointGeometry || geom.isMultipart() )
       return QVariant();
 
-    QgsPoint *point = qgsgeometry_cast< QgsPoint * >( geom.geometry() );
+    const QgsPoint *point = qgsgeometry_cast< const QgsPoint * >( geom.constGet() );
     if ( !point )
       return QVariant();
 
@@ -2035,7 +2035,7 @@ static QVariant fcnMakeCircle( const QVariantList &values, const QgsExpressionCo
     parent->setEvalErrorString( QObject::tr( "Segment must be greater than 2" ) );
     return QVariant();
   }
-  QgsPoint *point = qgsgeometry_cast< QgsPoint * >( geom.geometry() );
+  const QgsPoint *point = qgsgeometry_cast< const QgsPoint * >( geom.constGet() );
   QgsCircle circ( *point, radius );
   return QVariant::fromValue( QgsGeometry( circ.toPolygon( segment ) ) );
 }
@@ -2058,7 +2058,7 @@ static QVariant fcnMakeEllipse( const QVariantList &values, const QgsExpressionC
     parent->setEvalErrorString( QObject::tr( "Segment must be greater than 2" ) );
     return QVariant();
   }
-  QgsPoint *point = qgsgeometry_cast< QgsPoint * >( geom.geometry() );
+  const QgsPoint *point = qgsgeometry_cast< const QgsPoint * >( geom.constGet() );
   QgsEllipse elp( *point, majorAxis,  minorAxis, azimuth );
   return QVariant::fromValue( QgsGeometry( elp.toPolygon( segment ) ) );
 }
@@ -2093,8 +2093,8 @@ static QVariant fcnMakeRegularPolygon( const QVariantList &values, const QgsExpr
     parent->setEvalErrorString( QObject::tr( "Option can be 0 (inscribed) or 1 (circumscribed)" ) );
     return QVariant();
   }
-  QgsPoint *center = qgsgeometry_cast< QgsPoint * >( pt1.geometry() );
-  QgsPoint *corner = qgsgeometry_cast< QgsPoint * >( pt2.geometry() );
+  const QgsPoint *center = qgsgeometry_cast< const QgsPoint * >( pt1.constGet() );
+  const QgsPoint *corner = qgsgeometry_cast< const QgsPoint * >( pt2.constGet() );
 
   QgsRegularPolygon rp = QgsRegularPolygon( *center, *corner, nbEdges, option );
 
@@ -2112,9 +2112,9 @@ static QVariant pointAt( const QVariantList &values, const QgsExpressionContext
 
   if ( idx < 0 )
   {
-    idx += g.geometry()->nCoordinates();
+    idx += g.constGet()->nCoordinates();
   }
-  if ( idx < 0 || idx >= g.geometry()->nCoordinates() )
+  if ( idx < 0 || idx >= g.constGet()->nCoordinates() )
   {
     parent->setEvalErrorString( QObject::tr( "Index is out of range" ) );
     return QVariant();
@@ -2221,7 +2221,7 @@ static QVariant fcnGeomPerimeter( const QVariantList &, const QgsExpressionConte
   }
   else
   {
-    return f.geometry().isNull() ? QVariant( 0 ) : QVariant( f.geometry().geometry()->perimeter() );
+    return f.geometry().isNull() ? QVariant( 0 ) : QVariant( f.geometry().constGet()->perimeter() );
   }
 }
 
@@ -2239,7 +2239,7 @@ static QVariant fcnPerimeter( const QVariantList &values, const QgsExpressionCon
 static QVariant fcnGeomNumPoints( const QVariantList &values, const QgsExpressionContext *, QgsExpression *parent, const QgsExpressionNodeFunction * )
 {
   QgsGeometry geom = QgsExpressionUtils::getGeometry( values.at( 0 ), parent );
-  return QVariant( geom.isNull() ? 0 : geom.geometry()->nCoordinates() );
+  return QVariant( geom.isNull() ? 0 : geom.constGet()->nCoordinates() );
 }
 
 static QVariant fcnGeomNumGeometries( const QVariantList &values, const QgsExpressionContext *, QgsExpression *parent, const QgsExpressionNodeFunction * )
@@ -2248,7 +2248,7 @@ static QVariant fcnGeomNumGeometries( const QVariantList &values, const QgsExpre
   if ( geom.isNull() )
     return QVariant();
 
-  return QVariant( geom.geometry()->partCount() );
+  return QVariant( geom.constGet()->partCount() );
 }
 
 static QVariant fcnGeomNumInteriorRings( const QVariantList &values, const QgsExpressionContext *, QgsExpression *parent, const QgsExpressionNodeFunction * )
@@ -2258,17 +2258,17 @@ static QVariant fcnGeomNumInteriorRings( const QVariantList &values, const QgsEx
   if ( geom.isNull() )
     return QVariant();
 
-  QgsCurvePolygon *curvePolygon = qgsgeometry_cast< QgsCurvePolygon * >( geom.geometry() );
+  const QgsCurvePolygon *curvePolygon = qgsgeometry_cast< const QgsCurvePolygon * >( geom.constGet() );
   if ( curvePolygon )
     return QVariant( curvePolygon->numInteriorRings() );
 
-  QgsGeometryCollection *collection = qgsgeometry_cast< QgsGeometryCollection * >( geom.geometry() );
+  const QgsGeometryCollection *collection = qgsgeometry_cast< const QgsGeometryCollection * >( geom.constGet() );
   if ( collection )
   {
     //find first CurvePolygon in collection
     for ( int i = 0; i < collection->numGeometries(); ++i )
     {
-      curvePolygon = qgsgeometry_cast< QgsCurvePolygon *>( collection->geometryN( i ) );
+      curvePolygon = qgsgeometry_cast< const QgsCurvePolygon *>( collection->geometryN( i ) );
       if ( !curvePolygon )
         continue;
 
@@ -2286,13 +2286,13 @@ static QVariant fcnGeomNumRings( const QVariantList &values, const QgsExpression
   if ( geom.isNull() )
     return QVariant();
 
-  QgsCurvePolygon *curvePolygon = qgsgeometry_cast< QgsCurvePolygon * >( geom.geometry() );
+  const QgsCurvePolygon *curvePolygon = qgsgeometry_cast< const QgsCurvePolygon * >( geom.constGet() );
   if ( curvePolygon )
     return QVariant( curvePolygon->ringCount() );
 
   bool foundPoly = false;
   int ringCount = 0;
-  QgsGeometryCollection *collection = qgsgeometry_cast< QgsGeometryCollection * >( geom.geometry() );
+  const QgsGeometryCollection *collection = qgsgeometry_cast< const QgsGeometryCollection * >( geom.constGet() );
   if ( collection )
   {
     //find CurvePolygons in collection
@@ -2363,7 +2363,7 @@ static QVariant fcnIsClosed( const QVariantList &values, const QgsExpressionCont
   if ( fGeom.isNull() )
     return QVariant();
 
-  QgsCurve *curve = qgsgeometry_cast< QgsCurve * >( fGeom.geometry() );
+  const QgsCurve *curve = qgsgeometry_cast< const QgsCurve * >( fGeom.constGet() );
   if ( !curve )
     return QVariant();
 
@@ -2381,19 +2381,19 @@ static QVariant fcnRelate( const QVariantList &values, const QgsExpressionContex
   if ( fGeom.isNull() || sGeom.isNull() )
     return QVariant();
 
-  std::unique_ptr<QgsGeometryEngine> engine( QgsGeometry::createGeometryEngine( fGeom.geometry() ) );
+  std::unique_ptr<QgsGeometryEngine> engine( QgsGeometry::createGeometryEngine( fGeom.constGet() ) );
 
   if ( values.length() == 2 )
   {
     //two geometry arguments, return relation
-    QString result = engine->relate( sGeom.geometry() );
+    QString result = engine->relate( sGeom.constGet() );
     return QVariant::fromValue( result );
   }
   else
   {
     //three arguments, test pattern
     QString pattern = QgsExpressionUtils::getStringValue( values.at( 2 ), parent );
-    bool result = engine->relatePattern( sGeom.geometry(), pattern );
+    bool result = engine->relatePattern( sGeom.constGet(), pattern );
     return QVariant::fromValue( result );
   }
 }
@@ -2578,7 +2578,7 @@ static QVariant fcnReverse( const QVariantList &values, const QgsExpressionConte
   if ( fGeom.isNull() )
     return QVariant();
 
-  QgsCurve *curve = qgsgeometry_cast< QgsCurve * >( fGeom.geometry() );
+  const QgsCurve *curve = qgsgeometry_cast<const QgsCurve * >( fGeom.constGet() );
   if ( !curve )
     return QVariant();
 
@@ -2593,7 +2593,7 @@ static QVariant fcnExteriorRing( const QVariantList &values, const QgsExpression
   if ( fGeom.isNull() )
     return QVariant();
 
-  QgsCurvePolygon *curvePolygon = qgsgeometry_cast< QgsCurvePolygon * >( fGeom.geometry() );
+  const QgsCurvePolygon *curvePolygon = qgsgeometry_cast< const QgsCurvePolygon * >( fGeom.constGet() );
   if ( !curvePolygon || !curvePolygon->exteriorRing() )
     return QVariant();
 
@@ -2677,8 +2677,8 @@ static QVariant fcnAzimuth( const QVariantList &values, const QgsExpressionConte
   QgsGeometry fGeom1 = QgsExpressionUtils::getGeometry( values.at( 0 ), parent );
   QgsGeometry fGeom2 = QgsExpressionUtils::getGeometry( values.at( 1 ), parent );
 
-  const QgsPoint *pt1 = qgsgeometry_cast<const QgsPoint *>( fGeom1.geometry() );
-  const QgsPoint *pt2 = qgsgeometry_cast<const QgsPoint *>( fGeom2.geometry() );
+  const QgsPoint *pt1 = qgsgeometry_cast<const QgsPoint *>( fGeom1.constGet() );
+  const QgsPoint *pt2 = qgsgeometry_cast<const QgsPoint *>( fGeom2.constGet() );
 
   if ( !pt1 || !pt2 )
   {
@@ -2749,7 +2749,7 @@ static QVariant fcnProject( const QVariantList &values, const QgsExpressionConte
   double azimuth = QgsExpressionUtils::getDoubleValue( values.at( 2 ), parent );
   double inclination = QgsExpressionUtils::getDoubleValue( values.at( 3 ), parent );
 
-  const QgsPoint *p = static_cast<const QgsPoint *>( geom.geometry() );
+  const QgsPoint *p = static_cast<const QgsPoint *>( geom.constGet() );
   QgsPoint newPoint = p->project( distance,  180.0 * azimuth / M_PI, 180.0 * inclination / M_PI );
 
   return QVariant::fromValue( QgsGeometry( new QgsPoint( newPoint ) ) );
@@ -2760,8 +2760,8 @@ static QVariant fcnInclination( const QVariantList &values, const QgsExpressionC
   QgsGeometry fGeom1 = QgsExpressionUtils::getGeometry( values.at( 0 ), parent );
   QgsGeometry fGeom2 = QgsExpressionUtils::getGeometry( values.at( 1 ), parent );
 
-  const QgsPoint *pt1 = qgsgeometry_cast<const QgsPoint *>( fGeom1.geometry() );
-  const QgsPoint *pt2 = qgsgeometry_cast<const QgsPoint *>( fGeom2.geometry() );
+  const QgsPoint *pt1 = qgsgeometry_cast<const QgsPoint *>( fGeom1.constGet() );
+  const QgsPoint *pt2 = qgsgeometry_cast<const QgsPoint *>( fGeom2.constGet() );
 
   if ( ( fGeom1.type() != QgsWkbTypes::PointGeometry ) || ( fGeom2.type() != QgsWkbTypes::PointGeometry ) ||
        !pt1 || !pt2 )
@@ -2785,7 +2785,7 @@ static QVariant fcnExtrude( const QVariantList &values, const QgsExpressionConte
 
   QgsGeometry geom = fGeom.extrude( x, y );
 
-  QVariant result = geom.geometry() ? QVariant::fromValue( geom ) : QVariant();
+  QVariant result = geom.constGet() ? QVariant::fromValue( geom ) : QVariant();
   return result;
 }
 
@@ -2829,7 +2829,7 @@ static QVariant fcnOrderParts( const QVariantList &values, const QgsExpressionCo
     unconstedContext = new QgsExpressionContext();
   }
 
-  QgsGeometryCollection *collection = qgsgeometry_cast<QgsGeometryCollection *>( fGeom.geometry() );
+  const QgsGeometryCollection *collection = qgsgeometry_cast<const QgsGeometryCollection *>( fGeom.constGet() );
   Q_ASSERT( collection ); // Should have failed the multipart check above
 
   QgsFeatureRequest::OrderBy orderBy;
@@ -2846,7 +2846,7 @@ static QVariant fcnOrderParts( const QVariantList &values, const QgsExpressionCo
 
   sorter.sortFeatures( partFeatures, unconstedContext );
 
-  QgsGeometryCollection *orderedGeom = qgsgeometry_cast<QgsGeometryCollection *>( fGeom.geometry()->clone() );
+  QgsGeometryCollection *orderedGeom = qgsgeometry_cast<QgsGeometryCollection *>( fGeom.constGet()->clone() );
 
   Q_ASSERT( orderedGeom );
 
@@ -2855,7 +2855,7 @@ static QVariant fcnOrderParts( const QVariantList &values, const QgsExpressionCo
 
   for ( const QgsFeature &feature : qgis::as_const( partFeatures ) )
   {
-    orderedGeom->addGeometry( feature.geometry().geometry()->clone() );
+    orderedGeom->addGeometry( feature.geometry().constGet()->clone() );
   }
 
   QVariant result = QVariant::fromValue( QgsGeometry( orderedGeom ) );
diff --git a/src/core/geometry/qgsabstractgeometry.h b/src/core/geometry/qgsabstractgeometry.h
index bb3c937c736..736ccaff21c 100644
--- a/src/core/geometry/qgsabstractgeometry.h
+++ b/src/core/geometry/qgsabstractgeometry.h
@@ -298,7 +298,7 @@ class CORE_EXPORT QgsAbstractGeometry
      * Returns the vertices adjacent to a specified \a vertex within a geometry.
      * \since QGIS 3.0
      */
-    virtual void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex SIP_OUT, QgsVertexId &nextVertex SIP_OUT ) = 0;
+    virtual void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex SIP_OUT, QgsVertexId &nextVertex SIP_OUT ) const = 0;
 
     /**
      * Retrieves the sequence of geometries, rings and nodes.
diff --git a/src/core/geometry/qgscurve.cpp b/src/core/geometry/qgscurve.cpp
index fae2d4a45ec..30b41816cee 100644
--- a/src/core/geometry/qgscurve.cpp
+++ b/src/core/geometry/qgscurve.cpp
@@ -78,7 +78,7 @@ bool QgsCurve::nextVertex( QgsVertexId &id, QgsPoint &vertex ) const
   return pointAt( id.vertex, vertex, id.type );
 }
 
-void QgsCurve::adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex, QgsVertexId &nextVertex )
+void QgsCurve::adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex, QgsVertexId &nextVertex ) const
 {
   int n = numPoints();
   if ( vertex.vertex < 0 || vertex.vertex >= n )
diff --git a/src/core/geometry/qgscurve.h b/src/core/geometry/qgscurve.h
index 556fc7cb8fe..c258001dec1 100644
--- a/src/core/geometry/qgscurve.h
+++ b/src/core/geometry/qgscurve.h
@@ -103,7 +103,7 @@ class CORE_EXPORT QgsCurve: public QgsAbstractGeometry
 
     QgsCoordinateSequence coordinateSequence() const override;
     bool nextVertex( QgsVertexId &id, QgsPoint &vertex SIP_OUT ) const override;
-    void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex SIP_OUT, QgsVertexId &nextVertex SIP_OUT ) override;
+    void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex SIP_OUT, QgsVertexId &nextVertex SIP_OUT ) const override;
     int vertexNumberFromVertexId( QgsVertexId id ) const override;
 
     /**
diff --git a/src/core/geometry/qgscurvepolygon.cpp b/src/core/geometry/qgscurvepolygon.cpp
index 245c46c101f..d46b5bd4a17 100644
--- a/src/core/geometry/qgscurvepolygon.cpp
+++ b/src/core/geometry/qgscurvepolygon.cpp
@@ -844,7 +844,7 @@ void ringAdjacentVertices( const QgsCurve *curve, QgsVertexId vertex, QgsVertexI
   }
 }
 
-void QgsCurvePolygon::adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex, QgsVertexId &nextVertex )
+void QgsCurvePolygon::adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex, QgsVertexId &nextVertex ) const
 {
   if ( !mExteriorRing || vertex.ring < 0 || vertex.ring >= 1 + mInteriorRings.size() )
   {
diff --git a/src/core/geometry/qgscurvepolygon.h b/src/core/geometry/qgscurvepolygon.h
index 6465dc53412..873261e8563 100644
--- a/src/core/geometry/qgscurvepolygon.h
+++ b/src/core/geometry/qgscurvepolygon.h
@@ -123,7 +123,7 @@ class CORE_EXPORT QgsCurvePolygon: public QgsSurface
     double closestSegment( const QgsPoint &pt, QgsPoint &segmentPt SIP_OUT, QgsVertexId &vertexAfter SIP_OUT, bool *leftOf SIP_OUT = nullptr, double epsilon = 4 * DBL_EPSILON ) const override;
 
     bool nextVertex( QgsVertexId &id, QgsPoint &vertex SIP_OUT ) const override;
-    void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex SIP_OUT, QgsVertexId &nextVertex SIP_OUT ) override;
+    void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex SIP_OUT, QgsVertexId &nextVertex SIP_OUT ) const override;
     bool hasCurvedSegments() const override;
 
     /**
diff --git a/src/core/geometry/qgsgeometry.cpp b/src/core/geometry/qgsgeometry.cpp
index 9bf910934eb..cc180a02ea6 100644
--- a/src/core/geometry/qgsgeometry.cpp
+++ b/src/core/geometry/qgsgeometry.cpp
@@ -120,12 +120,18 @@ void QgsGeometry::reset( std::unique_ptr<QgsAbstractGeometry> newGeometry )
   d->geometry = std::move( newGeometry );
 }
 
-QgsAbstractGeometry *QgsGeometry::geometry() const
+const QgsAbstractGeometry *QgsGeometry::constGet() const
 {
   return d->geometry.get();
 }
 
-void QgsGeometry::setGeometry( QgsAbstractGeometry *geometry )
+QgsAbstractGeometry *QgsGeometry::get()
+{
+  detach();
+  return d->geometry.get();
+}
+
+void QgsGeometry::set( QgsAbstractGeometry *geometry )
 {
   if ( d->geometry.get() == geometry )
   {
@@ -872,7 +878,7 @@ int QgsGeometry::makeDifferenceInPlace( const QgsGeometry &other )
   QgsGeos geos( d->geometry.get() );
 
   mLastError.clear();
-  std::unique_ptr< QgsAbstractGeometry > diffGeom( geos.intersection( other.geometry(), &mLastError ) );
+  std::unique_ptr< QgsAbstractGeometry > diffGeom( geos.intersection( other.constGet(), &mLastError ) );
   if ( !diffGeom )
   {
     return 1;
@@ -892,7 +898,7 @@ QgsGeometry QgsGeometry::makeDifference( const QgsGeometry &other ) const
   QgsGeos geos( d->geometry.get() );
 
   mLastError.clear();
-  std::unique_ptr< QgsAbstractGeometry > diffGeom( geos.intersection( other.geometry(), &mLastError ) );
+  std::unique_ptr< QgsAbstractGeometry > diffGeom( geos.intersection( other.constGet(), &mLastError ) );
   if ( !diffGeom )
   {
     QgsGeometry result;
@@ -932,10 +938,10 @@ QgsGeometry QgsGeometry::orientedMinimumBoundingBox( double &area, double &angle
   QgsPoint pt1;
   QgsPoint pt2;
   // get first point
-  hull.geometry()->nextVertex( vertexId, pt0 );
+  hull.constGet()->nextVertex( vertexId, pt0 );
   pt1 = pt0;
   double prevAngle = 0.0;
-  while ( hull.geometry()->nextVertex( vertexId, pt2 ) )
+  while ( hull.constGet()->nextVertex( vertexId, pt2 ) )
   {
     double currentAngle = QgsGeometryUtils::lineAngle( pt1.x(), pt1.y(), pt2.x(), pt2.y() );
     double rotateAngle = 180.0 / M_PI * ( currentAngle - prevAngle );
@@ -945,9 +951,9 @@ QgsGeometry QgsGeometry::orientedMinimumBoundingBox( double &area, double &angle
     t.rotate( rotateAngle );
     t.translate( -pt0.x(), -pt0.y() );
 
-    hull.geometry()->transform( t );
+    hull.get()->transform( t );
 
-    QgsRectangle bounds = hull.geometry()->boundingBox();
+    QgsRectangle bounds = hull.constGet()->boundingBox();
     double currentArea = bounds.width() * bounds.height();
     if ( currentArea  < area )
     {
@@ -1047,7 +1053,7 @@ QgsGeometry QgsGeometry::minimalEnclosingCircle( QgsPointXY &center, double &rad
   center = QgsPointXY( circ.center() );
   radius = circ.radius();
   QgsGeometry geom;
-  geom.setGeometry( circ.toPolygon( segments ) );
+  geom.set( circ.toPolygon( segments ) );
   return geom;
 
 }
@@ -1816,7 +1822,7 @@ QgsGeometry QgsGeometry::voronoiDiagram( const QgsGeometry &extent, double toler
 
   QgsGeos geos( d->geometry.get() );
   mLastError.clear();
-  QgsGeometry result = geos.voronoiDiagram( extent.geometry(), tolerance, edgesOnly, &mLastError );
+  QgsGeometry result = geos.voronoiDiagram( extent.constGet(), tolerance, edgesOnly, &mLastError );
   result.mLastError = mLastError;
   return result;
 }
@@ -1873,7 +1879,7 @@ QgsGeometry QgsGeometry::interpolate( double distance ) const
   if ( type() == QgsWkbTypes::PolygonGeometry )
     line = QgsGeometry( d->geometry->boundary() );
 
-  QgsGeos geos( line.geometry() );
+  QgsGeos geos( line.constGet() );
   mLastError.clear();
   std::unique_ptr< QgsAbstractGeometry > result( geos.interpolate( distance, &mLastError ) );
   if ( !result )
@@ -1918,7 +1924,7 @@ double QgsGeometry::interpolateAngle( double distance ) const
 
   QgsVertexId previous;
   QgsVertexId next;
-  if ( !QgsGeometryUtils::verticesAtDistance( *segmentized.geometry(), distance, previous, next ) )
+  if ( !QgsGeometryUtils::verticesAtDistance( *segmentized.constGet(), distance, previous, next ) )
     return 0.0;
 
   if ( previous == next )
@@ -1927,33 +1933,33 @@ double QgsGeometry::interpolateAngle( double distance ) const
     QgsVertexId v2 = previous;
     QgsVertexId v1;
     QgsVertexId v3;
-    segmentized.geometry()->adjacentVertices( v2, v1, v3 );
+    segmentized.constGet()->adjacentVertices( v2, v1, v3 );
     if ( v1.isValid() && v3.isValid() )
     {
-      QgsPoint p1 = segmentized.geometry()->vertexAt( v1 );
-      QgsPoint p2 = segmentized.geometry()->vertexAt( v2 );
-      QgsPoint p3 = segmentized.geometry()->vertexAt( v3 );
+      QgsPoint p1 = segmentized.constGet()->vertexAt( v1 );
+      QgsPoint p2 = segmentized.constGet()->vertexAt( v2 );
+      QgsPoint p3 = segmentized.constGet()->vertexAt( v3 );
       double angle1 = QgsGeometryUtils::lineAngle( p1.x(), p1.y(), p2.x(), p2.y() );
       double angle2 = QgsGeometryUtils::lineAngle( p2.x(), p2.y(), p3.x(), p3.y() );
       return QgsGeometryUtils::averageAngle( angle1, angle2 );
     }
     else if ( v3.isValid() )
     {
-      QgsPoint p1 = segmentized.geometry()->vertexAt( v2 );
-      QgsPoint p2 = segmentized.geometry()->vertexAt( v3 );
+      QgsPoint p1 = segmentized.constGet()->vertexAt( v2 );
+      QgsPoint p2 = segmentized.constGet()->vertexAt( v3 );
       return QgsGeometryUtils::lineAngle( p1.x(), p1.y(), p2.x(), p2.y() );
     }
     else
     {
-      QgsPoint p1 = segmentized.geometry()->vertexAt( v1 );
-      QgsPoint p2 = segmentized.geometry()->vertexAt( v2 );
+      QgsPoint p1 = segmentized.constGet()->vertexAt( v1 );
+      QgsPoint p2 = segmentized.constGet()->vertexAt( v2 );
       return QgsGeometryUtils::lineAngle( p1.x(), p1.y(), p2.x(), p2.y() );
     }
   }
   else
   {
-    QgsPoint p1 = segmentized.geometry()->vertexAt( previous );
-    QgsPoint p2 = segmentized.geometry()->vertexAt( next );
+    QgsPoint p1 = segmentized.constGet()->vertexAt( previous );
+    QgsPoint p2 = segmentized.constGet()->vertexAt( next );
     return QgsGeometryUtils::lineAngle( p1.x(), p1.y(), p2.x(), p2.y() );
   }
 }
@@ -2152,7 +2158,7 @@ bool QgsGeometry::deletePart( int partNum )
 
   if ( !isMultipart() && partNum < 1 )
   {
-    setGeometry( nullptr );
+    set( nullptr );
     return true;
   }
 
@@ -2250,7 +2256,7 @@ QgsGeometry QgsGeometry::polygonize( const QList<QgsGeometry> &geometryList )
   {
     if ( !( g.isNull() ) )
     {
-      geomV2List.append( g.geometry() );
+      geomV2List.append( g.constGet() );
     }
   }
 
@@ -3107,7 +3113,7 @@ QDataStream &operator>>( QDataStream &in, QgsGeometry &geometry )
   in >> byteArray;
   if ( byteArray.isEmpty() )
   {
-    geometry.setGeometry( nullptr );
+    geometry.set( nullptr );
     return in;
   }
 
diff --git a/src/core/geometry/qgsgeometry.h b/src/core/geometry/qgsgeometry.h
index 97f8dddca1c..7eb801f179b 100644
--- a/src/core/geometry/qgsgeometry.h
+++ b/src/core/geometry/qgsgeometry.h
@@ -164,18 +164,42 @@ class CORE_EXPORT QgsGeometry
     ~QgsGeometry();
 
     /**
-     * Returns the underlying geometry store.
-    * \since QGIS 2.10
-    * \see setGeometry
+     * Returns a non-modifiable (const) reference to the underlying abstract geometry primitive.
+     *
+     * This is much faster then calling the non-const get() method.
+     *
+     * \note In QGIS 2.x this method was named geometry().
+     *
+     * \since QGIS 3.0
+     * \see primitive()
+     * \see set()
     */
-    QgsAbstractGeometry *geometry() const;
+    const QgsAbstractGeometry *constGet() const;
+
+    /**
+     * Returns a modifiable (non-const) reference to the underlying abstract geometry primitive.
+     *
+     * This method can be slow to call, as it may trigger a detachment of the geometry
+     * and a deep copy. Where possible, use constGet() instead.
+     *
+     * \note In QGIS 2.x this method was named geometry().
+     *
+     * \since QGIS 3.0
+     * \see constGet()
+     * \see set()
+    */
+    QgsAbstractGeometry *get();
 
     /**
      * Sets the underlying geometry store. Ownership of geometry is transferred.
-     * \since QGIS 2.10
-     * \see geometry
+     *
+     * \note In QGIS 2.x this method was named setGeometry().
+     *
+     * \since QGIS 3.0
+     * \see get()
+     * \see constGet()
      */
-    void setGeometry( QgsAbstractGeometry *geometry SIP_TRANSFER );
+    void set( QgsAbstractGeometry *geometry SIP_TRANSFER );
 
     /**
      * Returns true if the geometry is null (ie, contains no underlying geometry
diff --git a/src/core/geometry/qgsgeometrycollection.cpp b/src/core/geometry/qgsgeometrycollection.cpp
index 02f27b8680a..7db38d2a380 100644
--- a/src/core/geometry/qgsgeometrycollection.cpp
+++ b/src/core/geometry/qgsgeometrycollection.cpp
@@ -80,7 +80,7 @@ QgsAbstractGeometry *QgsGeometryCollection::boundary() const
   return nullptr;
 }
 
-void QgsGeometryCollection::adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex, QgsVertexId &nextVertex )
+void QgsGeometryCollection::adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex, QgsVertexId &nextVertex ) const
 {
   if ( vertex.part < 0 || vertex.part >= mGeometries.count() )
   {
diff --git a/src/core/geometry/qgsgeometrycollection.h b/src/core/geometry/qgsgeometrycollection.h
index 753b8bc6db7..b7d396fc828 100644
--- a/src/core/geometry/qgsgeometrycollection.h
+++ b/src/core/geometry/qgsgeometrycollection.h
@@ -65,7 +65,7 @@ class CORE_EXPORT QgsGeometryCollection: public QgsAbstractGeometry
     QString geometryType() const override;
     void clear() override;
     QgsAbstractGeometry *boundary() const override SIP_FACTORY;
-    void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex SIP_OUT, QgsVertexId &nextVertex SIP_OUT ) override;
+    void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex SIP_OUT, QgsVertexId &nextVertex SIP_OUT ) const override;
     int vertexNumberFromVertexId( QgsVertexId id ) const override;
 
     //! Adds a geometry and takes ownership. Returns true in case of success.
diff --git a/src/core/geometry/qgsgeos.cpp b/src/core/geometry/qgsgeos.cpp
index 1f65f83241f..3cd55733136 100644
--- a/src/core/geometry/qgsgeos.cpp
+++ b/src/core/geometry/qgsgeos.cpp
@@ -341,7 +341,7 @@ QgsAbstractGeometry *QgsGeos::combine( const QList<QgsGeometry> &geomList, QStri
     if ( !g )
       continue;
 
-    geosGeometries << asGeos( g.geometry(), mPrecision ).release();
+    geosGeometries << asGeos( g.constGet(), mPrecision ).release();
   }
 
   geos::unique_ptr geomUnion;
@@ -2043,7 +2043,7 @@ QgsGeometry QgsGeos::closestPoint( const QgsGeometry &other, QString *errorMsg )
     return QgsGeometry();
   }
 
-  geos::unique_ptr otherGeom( asGeos( other.geometry(), mPrecision ) );
+  geos::unique_ptr otherGeom( asGeos( other.constGet(), mPrecision ) );
   if ( !otherGeom )
   {
     return QgsGeometry();
@@ -2077,7 +2077,7 @@ QgsGeometry QgsGeos::shortestLine( const QgsGeometry &other, QString *errorMsg )
     return QgsGeometry();
   }
 
-  geos::unique_ptr otherGeom( asGeos( other.geometry(), mPrecision ) );
+  geos::unique_ptr otherGeom( asGeos( other.constGet(), mPrecision ) );
   if ( !otherGeom )
   {
     return QgsGeometry();
diff --git a/src/core/geometry/qgsinternalgeometryengine.cpp b/src/core/geometry/qgsinternalgeometryengine.cpp
index 4e2e58fc408..6561c6303bf 100644
--- a/src/core/geometry/qgsinternalgeometryengine.cpp
+++ b/src/core/geometry/qgsinternalgeometryengine.cpp
@@ -29,7 +29,7 @@
 #include <queue>
 
 QgsInternalGeometryEngine::QgsInternalGeometryEngine( const QgsGeometry &geometry )
-  : mGeometry( geometry.geometry() )
+  : mGeometry( geometry.constGet() )
 {
 
 }
diff --git a/src/core/geometry/qgspoint.cpp b/src/core/geometry/qgspoint.cpp
index bfefc74ea4f..5543a00fb09 100644
--- a/src/core/geometry/qgspoint.cpp
+++ b/src/core/geometry/qgspoint.cpp
@@ -401,7 +401,7 @@ bool QgsPoint::nextVertex( QgsVertexId &id, QgsPoint &vertex ) const
   }
 }
 
-void QgsPoint::adjacentVertices( QgsVertexId, QgsVertexId &previousVertex, QgsVertexId &nextVertex )
+void QgsPoint::adjacentVertices( QgsVertexId, QgsVertexId &previousVertex, QgsVertexId &nextVertex ) const
 {
   previousVertex = QgsVertexId();
   nextVertex = QgsVertexId();
diff --git a/src/core/geometry/qgspoint.h b/src/core/geometry/qgspoint.h
index 16d8f1581f2..b7744a78af6 100644
--- a/src/core/geometry/qgspoint.h
+++ b/src/core/geometry/qgspoint.h
@@ -415,7 +415,7 @@ class CORE_EXPORT QgsPoint: public QgsAbstractGeometry
 
     double closestSegment( const QgsPoint &pt, QgsPoint &segmentPt SIP_OUT, QgsVertexId &vertexAfter SIP_OUT, bool *leftOf SIP_OUT = nullptr, double epsilon = 4 * DBL_EPSILON ) const override;
     bool nextVertex( QgsVertexId &id, QgsPoint &vertex SIP_OUT ) const override;
-    void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex SIP_OUT, QgsVertexId &nextVertex SIP_OUT ) override;
+    void adjacentVertices( QgsVertexId vertex, QgsVertexId &previousVertex SIP_OUT, QgsVertexId &nextVertex SIP_OUT ) const override;
 
     /**
      * Angle undefined. Always returns 0.0
diff --git a/src/core/providers/memory/qgsmemoryfeatureiterator.cpp b/src/core/providers/memory/qgsmemoryfeatureiterator.cpp
index 117593e345c..f2083276352 100644
--- a/src/core/providers/memory/qgsmemoryfeatureiterator.cpp
+++ b/src/core/providers/memory/qgsmemoryfeatureiterator.cpp
@@ -52,7 +52,7 @@ QgsMemoryFeatureIterator::QgsMemoryFeatureIterator( QgsMemoryFeatureSource *sour
   if ( !mFilterRect.isNull() && mRequest.flags() & QgsFeatureRequest::ExactIntersect )
   {
     mSelectRectGeom = QgsGeometry::fromRect( mFilterRect );
-    mSelectRectEngine.reset( QgsGeometry::createGeometryEngine( mSelectRectGeom.geometry() ) );
+    mSelectRectEngine.reset( QgsGeometry::createGeometryEngine( mSelectRectGeom.constGet() ) );
     mSelectRectEngine->prepareGeometry();
   }
 
@@ -111,7 +111,7 @@ bool QgsMemoryFeatureIterator::nextFeatureUsingList( QgsFeature &feature )
     if ( !mFilterRect.isNull() && mRequest.flags() & QgsFeatureRequest::ExactIntersect )
     {
       // do exact check in case we're doing intersection
-      if ( mSource->mFeatures.value( *mFeatureIdListIterator ).hasGeometry() && mSelectRectEngine->intersects( mSource->mFeatures.value( *mFeatureIdListIterator ).geometry().geometry() ) )
+      if ( mSource->mFeatures.value( *mFeatureIdListIterator ).hasGeometry() && mSelectRectEngine->intersects( mSource->mFeatures.value( *mFeatureIdListIterator ).geometry().constGet() ) )
         hasFeature = true;
     }
     else
@@ -166,7 +166,7 @@ bool QgsMemoryFeatureIterator::nextFeatureTraverseAll( QgsFeature &feature )
       if ( mRequest.flags() & QgsFeatureRequest::ExactIntersect )
       {
         // using exact test when checking for intersection
-        if ( mSelectIterator->hasGeometry() && mSelectRectEngine->intersects( mSelectIterator->geometry().geometry() ) )
+        if ( mSelectIterator->hasGeometry() && mSelectRectEngine->intersects( mSelectIterator->geometry().constGet() ) )
           hasFeature = true;
       }
       else
diff --git a/src/core/qgsdistancearea.cpp b/src/core/qgsdistancearea.cpp
index 9e4cd4fc512..3887a399759 100644
--- a/src/core/qgsdistancearea.cpp
+++ b/src/core/qgsdistancearea.cpp
@@ -180,7 +180,7 @@ double QgsDistanceArea::measureArea( const QgsGeometry &geometry ) const
   if ( geometry.isNull() )
     return 0.0;
 
-  const QgsAbstractGeometry *geomV2 = geometry.geometry();
+  const QgsAbstractGeometry *geomV2 = geometry.constGet();
   return measure( geomV2, Area );
 }
 
@@ -189,7 +189,7 @@ double QgsDistanceArea::measureLength( const QgsGeometry &geometry ) const
   if ( geometry.isNull() )
     return 0.0;
 
-  const QgsAbstractGeometry *geomV2 = geometry.geometry();
+  const QgsAbstractGeometry *geomV2 = geometry.constGet();
   return measure( geomV2, Length );
 }
 
@@ -198,7 +198,7 @@ double QgsDistanceArea::measurePerimeter( const QgsGeometry &geometry ) const
   if ( geometry.isNull() )
     return 0.0;
 
-  const QgsAbstractGeometry *geomV2 = geometry.geometry();
+  const QgsAbstractGeometry *geomV2 = geometry.constGet();
   if ( !geomV2 || geomV2->dimension() < 2 )
   {
     return 0.0;
diff --git a/src/core/qgsjsonutils.cpp b/src/core/qgsjsonutils.cpp
index 90455276f80..36d59554da9 100644
--- a/src/core/qgsjsonutils.cpp
+++ b/src/core/qgsjsonutils.cpp
@@ -93,7 +93,7 @@ QString QgsJsonExporter::exportFeature( const QgsFeature &feature, const QVarian
     }
     QgsRectangle box = geom.boundingBox();
 
-    if ( QgsWkbTypes::flatType( geom.geometry()->wkbType() ) != QgsWkbTypes::Point )
+    if ( QgsWkbTypes::flatType( geom.wkbType() ) != QgsWkbTypes::Point )
     {
       s += QStringLiteral( "   \"bbox\":[%1, %2, %3, %4],\n" ).arg( qgsDoubleToString( box.xMinimum(), mPrecision ),
            qgsDoubleToString( box.yMinimum(), mPrecision ),
diff --git a/src/core/qgsmaphittest.cpp b/src/core/qgsmaphittest.cpp
index 6e75c0b55c5..cc4b68d5d69 100644
--- a/src/core/qgsmaphittest.cpp
+++ b/src/core/qgsmaphittest.cpp
@@ -133,7 +133,7 @@ void QgsMapHitTest::runHitTestLayer( QgsVectorLayer *vl, SymbolSet &usedSymbols,
     else
     {
       request.setFilterRect( transformedPolygon.boundingBox() );
-      polygonEngine.reset( QgsGeometry::createGeometryEngine( transformedPolygon.geometry() ) );
+      polygonEngine.reset( QgsGeometry::createGeometryEngine( transformedPolygon.constGet() ) );
       polygonEngine->prepareGeometry();
     }
   }
@@ -155,7 +155,7 @@ void QgsMapHitTest::runHitTestLayer( QgsVectorLayer *vl, SymbolSet &usedSymbols,
     // filter out elements outside of the polygon
     if ( f.geometry() && polygonEngine )
     {
-      if ( !polygonEngine->intersects( f.geometry().geometry() ) )
+      if ( !polygonEngine->intersects( f.geometry().constGet() ) )
       {
         continue;
       }
diff --git a/src/core/qgsmaptopixelgeometrysimplifier.cpp b/src/core/qgsmaptopixelgeometrysimplifier.cpp
index f6f877ba5b0..e4fd2df69c2 100644
--- a/src/core/qgsmaptopixelgeometrysimplifier.cpp
+++ b/src/core/qgsmaptopixelgeometrysimplifier.cpp
@@ -269,11 +269,11 @@ QgsGeometry QgsMapToPixelSimplifier::simplifyGeometry(
   {
     const QgsPolygonV2 &srcPolygon = dynamic_cast<const QgsPolygonV2 &>( geometry );
     std::unique_ptr<QgsPolygonV2> polygon( new QgsPolygonV2() );
-    polygon->setExteriorRing( qgsgeometry_cast<QgsCurve *>( simplifyGeometry( simplifyFlags, simplifyAlgorithm, srcPolygon.exteriorRing()->wkbType(), *srcPolygon.exteriorRing(), envelope, map2pixelTol, true ).geometry()->clone() ) );
+    polygon->setExteriorRing( qgsgeometry_cast<QgsCurve *>( simplifyGeometry( simplifyFlags, simplifyAlgorithm, srcPolygon.exteriorRing()->wkbType(), *srcPolygon.exteriorRing(), envelope, map2pixelTol, true ).constGet()->clone() ) );
     for ( int i = 0; i < srcPolygon.numInteriorRings(); ++i )
     {
       const QgsCurve *sub = srcPolygon.interiorRing( i );
-      polygon->addInteriorRing( qgsgeometry_cast<QgsCurve *>( simplifyGeometry( simplifyFlags, simplifyAlgorithm, sub->wkbType(), *sub, envelope, map2pixelTol, true ).geometry()->clone() ) );
+      polygon->addInteriorRing( qgsgeometry_cast<QgsCurve *>( simplifyGeometry( simplifyFlags, simplifyAlgorithm, sub->wkbType(), *sub, envelope, map2pixelTol, true ).constGet()->clone() ) );
     }
     return QgsGeometry( polygon.release() );
   }
@@ -285,7 +285,7 @@ QgsGeometry QgsMapToPixelSimplifier::simplifyGeometry(
     for ( int i = 0; i < numGeoms; ++i )
     {
       const QgsAbstractGeometry *sub = srcCollection.geometryN( i );
-      collection->addGeometry( simplifyGeometry( simplifyFlags, simplifyAlgorithm, sub->wkbType(), *sub, envelope, map2pixelTol, false ).geometry()->clone() );
+      collection->addGeometry( simplifyGeometry( simplifyFlags, simplifyAlgorithm, sub->wkbType(), *sub, envelope, map2pixelTol, false ).constGet()->clone() );
     }
     return QgsGeometry( collection.release() );
   }
@@ -320,7 +320,7 @@ QgsGeometry QgsMapToPixelSimplifier::simplify( const QgsGeometry &geometry ) con
   }
 
   const bool isaLinearRing = flatType == QgsWkbTypes::Polygon;
-  const int numPoints = geometry.geometry()->nCoordinates();
+  const int numPoints = geometry.constGet()->nCoordinates();
 
   if ( numPoints <= ( isaLinearRing ? 6 : 3 ) )
   {
@@ -335,5 +335,5 @@ QgsGeometry QgsMapToPixelSimplifier::simplify( const QgsGeometry &geometry ) con
     return geometry;
   }
 
-  return simplifyGeometry( mSimplifyFlags, mSimplifyAlgorithm, geometry.wkbType(), *geometry.geometry(), envelope, mTolerance, false );
+  return simplifyGeometry( mSimplifyFlags, mSimplifyAlgorithm, geometry.wkbType(), *geometry.constGet(), envelope, mTolerance, false );
 }
diff --git a/src/core/qgspallabeling.cpp b/src/core/qgspallabeling.cpp
index fc332195fdc..cff1418d906 100644
--- a/src/core/qgspallabeling.cpp
+++ b/src/core/qgspallabeling.cpp
@@ -1494,7 +1494,7 @@ void QgsPalLayerSettings::registerFeature( QgsFeature &f, QgsRenderContext &cont
   if ( ( geom.type() == QgsWkbTypes::PolygonGeometry )
        && ( placement == Line || placement == PerimeterCurved ) )
   {
-    geom = QgsGeometry( geom.geometry()->boundary() );
+    geom = QgsGeometry( geom.constGet()->boundary() );
   }
 
   GEOSGeometry *geos_geom_clone = nullptr;
@@ -1779,8 +1779,8 @@ void QgsPalLayerSettings::registerFeature( QgsFeature &f, QgsRenderContext &cont
         if ( QgsPalLabeling::geometryRequiresPreparation( ddPoint, context, ct ) )
         {
           ddPoint = QgsPalLabeling::prepareGeometry( ddPoint, context, ct );
-          xPos = static_cast< QgsPoint * >( ddPoint.geometry() )->x();
-          yPos = static_cast< QgsPoint * >( ddPoint.geometry() )->y();
+          xPos = static_cast< const QgsPoint * >( ddPoint.constGet() )->x();
+          yPos = static_cast< const QgsPoint * >( ddPoint.constGet() )->y();
         }
 
         xPos += xdiff;
diff --git a/src/core/qgstracer.cpp b/src/core/qgstracer.cpp
index d2e871a0776..702699bd630 100644
--- a/src/core/qgstracer.cpp
+++ b/src/core/qgstracer.cpp
@@ -414,16 +414,16 @@ void extractLinework( const QgsGeometry &g, QgsMultiPolyline &mpl )
   QgsGeometry geom = g;
   // segmentize curved geometries - we will use noding algorithm from GEOS
   // to find all intersections a bit later (so we need them segmentized anyway)
-  if ( QgsWkbTypes::isCurvedType( g.geometry()->wkbType() ) )
+  if ( QgsWkbTypes::isCurvedType( g.wkbType() ) )
   {
-    QgsAbstractGeometry *segmentizedGeomV2 = g.geometry()->segmentize();
+    QgsAbstractGeometry *segmentizedGeomV2 = g.constGet()->segmentize();
     if ( !segmentizedGeomV2 )
       return;
 
     geom = QgsGeometry( segmentizedGeomV2 );
   }
 
-  switch ( QgsWkbTypes::flatType( geom.geometry()->wkbType() ) )
+  switch ( QgsWkbTypes::flatType( geom.wkbType() ) )
   {
     case QgsWkbTypes::LineString:
       mpl << geom.asPolyline();
diff --git a/src/core/qgsvectordataprovider.cpp b/src/core/qgsvectordataprovider.cpp
index a8678f2308f..65e6edf9d76 100644
--- a/src/core/qgsvectordataprovider.cpp
+++ b/src/core/qgsvectordataprovider.cpp
@@ -692,7 +692,7 @@ QgsGeometry QgsVectorDataProvider::convertToProviderType( const QgsGeometry &geo
     return QgsGeometry();
   }
 
-  QgsAbstractGeometry *geometry = geom.geometry();
+  const QgsAbstractGeometry *geometry = geom.constGet();
   if ( !geometry )
   {
     return QgsGeometry();
diff --git a/src/core/qgsvectorfilewriter.cpp b/src/core/qgsvectorfilewriter.cpp
index a2fac302619..c4330c11f9e 100644
--- a/src/core/qgsvectorfilewriter.cpp
+++ b/src/core/qgsvectorfilewriter.cpp
@@ -2109,13 +2109,13 @@ OGRFeatureH QgsVectorFileWriter::createFeature( const QgsFeature &feature )
       QgsGeometry geom = feature.geometry();
 
       // turn single geometry to multi geometry if needed
-      if ( QgsWkbTypes::flatType( geom.geometry()->wkbType() ) != QgsWkbTypes::flatType( mWkbType ) &&
-           QgsWkbTypes::flatType( geom.geometry()->wkbType() ) == QgsWkbTypes::flatType( QgsWkbTypes::singleType( mWkbType ) ) )
+      if ( QgsWkbTypes::flatType( geom.wkbType() ) != QgsWkbTypes::flatType( mWkbType ) &&
+           QgsWkbTypes::flatType( geom.wkbType() ) == QgsWkbTypes::flatType( QgsWkbTypes::singleType( mWkbType ) ) )
       {
         geom.convertToMultiType();
       }
 
-      if ( geom.geometry()->wkbType() != mWkbType )
+      if ( geom.wkbType() != mWkbType )
       {
         OGRGeometryH mGeom2 = nullptr;
 
@@ -2127,10 +2127,10 @@ OGRFeatureH QgsVectorFileWriter::createFeature( const QgsFeature &feature )
           //so the exported WKB has a different type to what the OGRGeometry is expecting.
           //possibly this is handled already in OGR, but it should be fixed regardless by actually converting
           //geom to the correct WKB type
-          QgsWkbTypes::Type wkbType = geom.geometry()->wkbType();
+          QgsWkbTypes::Type wkbType = geom.wkbType();
           if ( wkbType >= QgsWkbTypes::PointZ && wkbType <= QgsWkbTypes::MultiPolygonZ )
           {
-            QgsWkbTypes::Type wkbType25d = static_cast<QgsWkbTypes::Type>( geom.geometry()->wkbType() - QgsWkbTypes::PointZ + QgsWkbTypes::Point25D );
+            QgsWkbTypes::Type wkbType25d = static_cast<QgsWkbTypes::Type>( geom.wkbType() - QgsWkbTypes::PointZ + QgsWkbTypes::Point25D );
             mGeom2 = createEmptyGeometry( wkbType25d );
           }
         }
@@ -2145,7 +2145,7 @@ OGRFeatureH QgsVectorFileWriter::createFeature( const QgsFeature &feature )
           //
           // Btw. OGRGeometry must be exactly of the type of the geometry which it will receive
           // i.e. Polygons can't be imported to OGRMultiPolygon
-          mGeom2 = createEmptyGeometry( geom.geometry()->wkbType() );
+          mGeom2 = createEmptyGeometry( geom.wkbType() );
         }
 
         if ( !mGeom2 )
@@ -2431,7 +2431,7 @@ QgsVectorFileWriter::writeAsVectorFormat( QgsVectorLayer *layer,
           }
         }
 
-        if ( fet.hasGeometry() && QgsWkbTypes::isMultiType( fet.geometry().geometry()->wkbType() ) )
+        if ( fet.hasGeometry() && QgsWkbTypes::isMultiType( fet.geometry().wkbType() ) )
         {
           destWkbType = QgsWkbTypes::multiType( destWkbType );
           break;
@@ -2526,7 +2526,7 @@ QgsVectorFileWriter::writeAsVectorFormat( QgsVectorLayer *layer,
       req.setFilterRect( filterRect );
     }
     filterRectGeometry = QgsGeometry::fromRect( options.filterExtent );
-    filterRectEngine.reset( QgsGeometry::createGeometryEngine( filterRectGeometry.geometry() ) );
+    filterRectEngine.reset( QgsGeometry::createGeometryEngine( filterRectGeometry.constGet() ) );
     filterRectEngine->prepareGeometry();
   }
 
@@ -2613,7 +2613,7 @@ QgsVectorFileWriter::writeAsVectorFormat( QgsVectorLayer *layer,
       }
     }
 
-    if ( fet.hasGeometry() && filterRectEngine && !filterRectEngine->intersects( fet.geometry().geometry() ) )
+    if ( fet.hasGeometry() && filterRectEngine && !filterRectEngine->intersects( fet.geometry().constGet() ) )
       continue;
 
     if ( attributes.empty() && options.skipAttributeCreation )
diff --git a/src/core/qgsvectorlayereditutils.cpp b/src/core/qgsvectorlayereditutils.cpp
index 7e9d7fca2e7..40845aa2a16 100644
--- a/src/core/qgsvectorlayereditutils.cpp
+++ b/src/core/qgsvectorlayereditutils.cpp
@@ -105,10 +105,10 @@ QgsVectorLayer::EditResult QgsVectorLayerEditUtils::deleteVertex( QgsFeatureId f
   if ( !geometry.deleteVertex( vertex ) )
     return QgsVectorLayer::EditFailed;
 
-  if ( geometry.geometry() && geometry.geometry()->nCoordinates() == 0 )
+  if ( geometry.constGet() && geometry.constGet()->nCoordinates() == 0 )
   {
     //last vertex deleted, set geometry to null
-    geometry.setGeometry( nullptr );
+    geometry.set( nullptr );
   }
 
   mLayer->editBuffer()->changeGeometry( featureId, geometry );
diff --git a/src/core/qgsvectorlayerlabelprovider.cpp b/src/core/qgsvectorlayerlabelprovider.cpp
index fde6b9d2b47..f156d466f7d 100644
--- a/src/core/qgsvectorlayerlabelprovider.cpp
+++ b/src/core/qgsvectorlayerlabelprovider.cpp
@@ -266,16 +266,16 @@ QgsGeometry QgsVectorLayerLabelProvider::getPointObstacleGeometry( QgsFeature &f
   if ( !fet.hasGeometry() || fet.geometry().type() != QgsWkbTypes::PointGeometry )
     return QgsGeometry();
 
-  bool isMultiPoint = fet.geometry().geometry()->nCoordinates() > 1;
+  bool isMultiPoint = fet.geometry().constGet()->nCoordinates() > 1;
   QgsAbstractGeometry *obstacleGeom = nullptr;
   if ( isMultiPoint )
     obstacleGeom = new QgsMultiPolygonV2();
 
   // for each point
-  for ( int i = 0; i < fet.geometry().geometry()->nCoordinates(); ++i )
+  for ( int i = 0; i < fet.geometry().constGet()->nCoordinates(); ++i )
   {
     QRectF bounds;
-    QgsPoint p = fet.geometry().geometry()->vertexAt( QgsVertexId( i, 0, 0 ) );
+    QgsPoint p = fet.geometry().constGet()->vertexAt( QgsVertexId( i, 0, 0 ) );
     double x = p.x();
     double y = p.y();
     double z = 0; // dummy variable for coordinate transforms
diff --git a/src/core/symbology/qgsfillsymbollayer.cpp b/src/core/symbology/qgsfillsymbollayer.cpp
index 1433dd5fc42..5d5caef6b93 100644
--- a/src/core/symbology/qgsfillsymbollayer.cpp
+++ b/src/core/symbology/qgsfillsymbollayer.cpp
@@ -3415,8 +3415,8 @@ void QgsCentroidFillSymbolLayer::renderPolygon( const QPolygonF &points, QList<Q
 
         if ( context.geometryPartCount() > 1 )
         {
-          QgsGeometry geom = feature->geometry();
-          const QgsGeometryCollection *geomCollection = static_cast<const QgsGeometryCollection *>( geom.geometry() );
+          const QgsGeometry geom = feature->geometry();
+          const QgsGeometryCollection *geomCollection = static_cast<const QgsGeometryCollection *>( geom.constGet() );
 
           double area = 0;
           double areaBiggest = 0;
diff --git a/src/core/symbology/qgsinvertedpolygonrenderer.cpp b/src/core/symbology/qgsinvertedpolygonrenderer.cpp
index ec094cf6ace..8c8e7b03240 100644
--- a/src/core/symbology/qgsinvertedpolygonrenderer.cpp
+++ b/src/core/symbology/qgsinvertedpolygonrenderer.cpp
@@ -285,7 +285,7 @@ void QgsInvertedPolygonRenderer::stopRender( QgsRenderContext &context )
       Q_FOREACH ( const QgsGeometry &geom, cit.geometries )
       {
         QgsMultiPolygon multi;
-        QgsWkbTypes::Type type = QgsWkbTypes::flatType( geom.geometry()->wkbType() );
+        QgsWkbTypes::Type type = QgsWkbTypes::flatType( geom.constGet()->wkbType() );
 
         if ( ( type == QgsWkbTypes::Polygon ) || ( type == QgsWkbTypes::CurvePolygon ) )
         {
diff --git a/src/core/symbology/qgspointdistancerenderer.cpp b/src/core/symbology/qgspointdistancerenderer.cpp
index 23256f99248..59cd25f8c95 100644
--- a/src/core/symbology/qgspointdistancerenderer.cpp
+++ b/src/core/symbology/qgspointdistancerenderer.cpp
@@ -142,7 +142,7 @@ void QgsPointDistanceRenderer::drawGroup( const ClusteredGroup &group, QgsRender
   QgsMultiPointV2 *groupMultiPoint = new QgsMultiPointV2();
   Q_FOREACH ( const GroupedFeature &f, group )
   {
-    groupMultiPoint->addGeometry( f.feature.geometry().geometry()->clone() );
+    groupMultiPoint->addGeometry( f.feature.geometry().constGet()->clone() );
   }
   QgsGeometry groupGeom( groupMultiPoint );
   QgsGeometry centroid = groupGeom.centroid();
diff --git a/src/core/symbology/qgssymbol.cpp b/src/core/symbology/qgssymbol.cpp
index 6959e0eaf23..1fbba98a886 100644
--- a/src/core/symbology/qgssymbol.cpp
+++ b/src/core/symbology/qgssymbol.cpp
@@ -674,7 +674,7 @@ class ExpressionContextScopePopper
 
 void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &context, int layer, bool selected, bool drawVertexMarker, int currentVertexMarkerType, int currentVertexMarkerSize )
 {
-  QgsGeometry geom = feature.geometry();
+  const QgsGeometry geom = feature.geometry();
   if ( geom.isNull() )
   {
     return;
@@ -682,14 +682,14 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
 
   QgsGeometry segmentizedGeometry = geom;
   bool usingSegmentizedGeometry = false;
-  context.setGeometry( geom.geometry() );
+  context.setGeometry( geom.constGet() );
 
   bool tileMapRendering = context.testFlag( QgsRenderContext::RenderMapTile );
 
   //convert curve types to normal point/line/polygon ones
-  if ( QgsWkbTypes::isCurvedType( geom.geometry()->wkbType() ) )
+  if ( QgsWkbTypes::isCurvedType( geom.constGet()->wkbType() ) )
   {
-    QgsAbstractGeometry *g = geom.geometry()->segmentize( context.segmentationTolerance(), context.segmentationToleranceType() );
+    QgsAbstractGeometry *g = geom.constGet()->segmentize( context.segmentationTolerance(), context.segmentationToleranceType() );
     if ( !g )
     {
       return;
@@ -698,7 +698,7 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
     usingSegmentizedGeometry = true;
   }
 
-  mSymbolRenderContext->setGeometryPartCount( segmentizedGeometry.geometry()->partCount() );
+  mSymbolRenderContext->setGeometryPartCount( segmentizedGeometry.constGet()->partCount() );
   mSymbolRenderContext->setGeometryPartNum( 1 );
 
   ExpressionContextScopePopper scopePopper;
@@ -729,7 +729,7 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
     segmentizedGeometry = simplifier.simplify( segmentizedGeometry );
   }
 
-  switch ( QgsWkbTypes::flatType( segmentizedGeometry.geometry()->wkbType() ) )
+  switch ( QgsWkbTypes::flatType( segmentizedGeometry.constGet()->wkbType() ) )
   {
     case QgsWkbTypes::Point:
     {
@@ -739,7 +739,7 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
         break;
       }
 
-      const QgsPoint *point = static_cast< const QgsPoint * >( segmentizedGeometry.geometry() );
+      const QgsPoint *point = static_cast< const QgsPoint * >( segmentizedGeometry.constGet() );
       const QPointF pt = _getPoint( context, *point );
       static_cast<QgsMarkerSymbol *>( this )->renderPoint( pt, &feature, context, layer, selected );
 
@@ -764,7 +764,7 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
         QgsDebugMsg( "linestring can be drawn only with line symbol!" );
         break;
       }
-      const QgsCurve &curve = dynamic_cast<const QgsCurve &>( *segmentizedGeometry.geometry() );
+      const QgsCurve &curve = dynamic_cast<const QgsCurve &>( *segmentizedGeometry.constGet() );
       const QPolygonF pts = _getLineString( context, curve, !tileMapRendering && clipFeaturesToExtent() );
       static_cast<QgsLineSymbol *>( this )->renderPolyline( pts, &feature, context, layer, selected );
 
@@ -784,7 +784,7 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
         QgsDebugMsg( "polygon can be drawn only with fill symbol!" );
         break;
       }
-      const QgsPolygonV2 &polygon = dynamic_cast<const QgsPolygonV2 &>( *segmentizedGeometry.geometry() );
+      const QgsPolygonV2 &polygon = dynamic_cast<const QgsPolygonV2 &>( *segmentizedGeometry.constGet() );
       if ( !polygon.exteriorRing() )
       {
         QgsDebugMsg( "cannot render polygon with no exterior ring" );
@@ -813,7 +813,7 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
         break;
       }
 
-      const QgsMultiPointV2 &mp = static_cast< const QgsMultiPointV2 & >( *segmentizedGeometry.geometry() );
+      const QgsMultiPointV2 &mp = static_cast< const QgsMultiPointV2 & >( *segmentizedGeometry.constGet() );
 
       if ( drawVertexMarker && !usingSegmentizedGeometry )
       {
@@ -846,7 +846,7 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
         break;
       }
 
-      const QgsGeometryCollection &geomCollection = dynamic_cast<const QgsGeometryCollection &>( *segmentizedGeometry.geometry() );
+      const QgsGeometryCollection &geomCollection = dynamic_cast<const QgsGeometryCollection &>( *segmentizedGeometry.constGet() );
 
       const unsigned int num = geomCollection.numGeometries();
       for ( unsigned int i = 0; i < num; ++i )
@@ -886,7 +886,7 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
       QPolygonF pts;
       QList<QPolygonF> holes;
 
-      const QgsGeometryCollection &geomCollection = dynamic_cast<const QgsGeometryCollection &>( *segmentizedGeometry.geometry() );
+      const QgsGeometryCollection &geomCollection = dynamic_cast<const QgsGeometryCollection &>( *segmentizedGeometry.constGet() );
       const unsigned int num = geomCollection.numGeometries();
 
       // Sort components by approximate area (probably a bit faster than using
@@ -939,7 +939,7 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
     }
     case QgsWkbTypes::GeometryCollection:
     {
-      const QgsGeometryCollection &geomCollection = dynamic_cast<const QgsGeometryCollection &>( *segmentizedGeometry.geometry() );
+      const QgsGeometryCollection &geomCollection = dynamic_cast<const QgsGeometryCollection &>( *segmentizedGeometry.constGet() );
       if ( geomCollection.numGeometries() == 0 )
       {
         // skip noise from empty geometry collections from simplification
@@ -951,7 +951,7 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
     default:
       QgsDebugMsg( QString( "feature %1: unsupported wkb type %2/%3 for rendering" )
                    .arg( feature.id() )
-                   .arg( QgsWkbTypes::displayString( geom.geometry()->wkbType() ) )
+                   .arg( QgsWkbTypes::displayString( geom.constGet()->wkbType() ) )
                    .arg( geom.wkbType(), 0, 16 ) );
   }
 
@@ -973,7 +973,7 @@ void QgsSymbol::renderFeature( const QgsFeature &feature, QgsRenderContext &cont
       QgsVertexId vertexId;
       double x, y, z;
       QPointF mapPoint;
-      while ( geom.geometry()->nextVertex( vertexId, vertexPoint ) )
+      while ( geom.constGet()->nextVertex( vertexId, vertexPoint ) )
       {
         //transform
         x = vertexPoint.x();
diff --git a/src/gui/qgsexpressionselectiondialog.cpp b/src/gui/qgsexpressionselectiondialog.cpp
index 5ec1b2f7662..0ed1dacbdc3 100644
--- a/src/gui/qgsexpressionselectiondialog.cpp
+++ b/src/gui/qgsexpressionselectiondialog.cpp
@@ -146,7 +146,7 @@ void QgsExpressionSelectionDialog::mButtonZoomToFeatures_clicked()
   while ( features.nextFeature( feat ) )
   {
     QgsGeometry geom = feat.geometry();
-    if ( geom.isNull() || geom.geometry()->isEmpty() )
+    if ( geom.isNull() || geom.constGet()->isEmpty() )
       continue;
 
     QgsRectangle r = mMapCanvas->mapSettings().layerExtentToOutputExtent( mLayer, geom.boundingBox() );
diff --git a/src/gui/qgsmapcanvas.cpp b/src/gui/qgsmapcanvas.cpp
index 045df60dcbb..0012671a14e 100644
--- a/src/gui/qgsmapcanvas.cpp
+++ b/src/gui/qgsmapcanvas.cpp
@@ -1018,7 +1018,7 @@ bool QgsMapCanvas::boundingBoxOfFeatureIds( const QgsFeatureIds &ids, QgsVectorL
     {
       errorMsg = tr( "Feature does not have a geometry" );
     }
-    else if ( geom.geometry()->isEmpty() )
+    else if ( geom.constGet()->isEmpty() )
     {
       errorMsg = tr( "Feature geometry is empty" );
     }
diff --git a/src/gui/qgsmaptoolcapture.cpp b/src/gui/qgsmaptoolcapture.cpp
index cd9c040ba19..2f463e7a18c 100644
--- a/src/gui/qgsmaptoolcapture.cpp
+++ b/src/gui/qgsmaptoolcapture.cpp
@@ -419,7 +419,7 @@ int QgsMapToolCapture::fetchLayerPoint( const QgsPointLocator::Match &match, Qgs
       QgsVertexId vId;
       if ( !f.geometry().vertexIdFromVertexNr( match.vertexIndex(), vId ) )
         return 2;
-      layerPoint = f.geometry().geometry()->vertexAt( vId );
+      layerPoint = f.geometry().constGet()->vertexAt( vId );
       return 0;
     }
     else
diff --git a/src/gui/qgsmaptoolidentify.cpp b/src/gui/qgsmaptoolidentify.cpp
index 92314f9ccbd..a3d71290d9f 100644
--- a/src/gui/qgsmaptoolidentify.cpp
+++ b/src/gui/qgsmaptoolidentify.cpp
@@ -376,14 +376,14 @@ QMap< QString, QString > QgsMapToolIdentify::featureDerivedAttributes( QgsFeatur
   if ( feature->hasGeometry() )
   {
     geometryType = feature->geometry().type();
-    wkbType = feature->geometry().geometry()->wkbType();
+    wkbType = feature->geometry().wkbType();
     //find closest vertex to clicked point
-    closestPoint = QgsGeometryUtils::closestVertex( *feature->geometry().geometry(), QgsPoint( layerPoint.x(), layerPoint.y() ), vId );
+    closestPoint = QgsGeometryUtils::closestVertex( *feature->geometry().constGet(), QgsPoint( layerPoint.x(), layerPoint.y() ), vId );
   }
 
   if ( QgsWkbTypes::isMultiType( wkbType ) )
   {
-    QString str = QLocale::system().toString( static_cast<const QgsGeometryCollection *>( feature->geometry().geometry() )->numGeometries() );
+    QString str = QLocale::system().toString( static_cast<const QgsGeometryCollection *>( feature->geometry().constGet() )->numGeometries() );
     derivedAttributes.insert( tr( "Parts" ), str );
     str = QLocale::system().toString( vId.part + 1 );
     derivedAttributes.insert( tr( "Part number" ), str );
@@ -396,7 +396,7 @@ QMap< QString, QString > QgsMapToolIdentify::featureDerivedAttributes( QgsFeatur
     QString str = formatDistance( dist );
     derivedAttributes.insert( tr( "Length" ), str );
 
-    const QgsCurve *curve = qgsgeometry_cast< const QgsCurve * >( feature->geometry().geometry() );
+    const QgsCurve *curve = qgsgeometry_cast< const QgsCurve * >( feature->geometry().constGet() );
     if ( curve )
     {
       str = QLocale::system().toString( curve->nCoordinates() );
@@ -431,11 +431,11 @@ QMap< QString, QString > QgsMapToolIdentify::featureDerivedAttributes( QgsFeatur
     str = formatDistance( perimeter );
     derivedAttributes.insert( tr( "Perimeter" ), str );
 
-    str = QLocale::system().toString( feature->geometry().geometry()->nCoordinates() );
+    str = QLocale::system().toString( feature->geometry().constGet()->nCoordinates() );
     derivedAttributes.insert( tr( "Vertices" ), str );
 
     //add details of closest vertex to identify point
-    closestVertexAttributes( *feature->geometry().geometry(), vId, layer, derivedAttributes );
+    closestVertexAttributes( *feature->geometry().constGet(), vId, layer, derivedAttributes );
   }
   else if ( geometryType == QgsWkbTypes::PointGeometry &&
             QgsWkbTypes::flatType( wkbType ) == QgsWkbTypes::Point )
@@ -449,12 +449,12 @@ QMap< QString, QString > QgsMapToolIdentify::featureDerivedAttributes( QgsFeatur
 
     if ( QgsWkbTypes::hasZ( wkbType ) )
     {
-      str = QLocale::system().toString( static_cast<const QgsPoint *>( feature->geometry().geometry() )->z(), 'g', 10 );
+      str = QLocale::system().toString( static_cast<const QgsPoint *>( feature->geometry().constGet() )->z(), 'g', 10 );
       derivedAttributes.insert( QStringLiteral( "Z" ), str );
     }
     if ( QgsWkbTypes::hasM( wkbType ) )
     {
-      str = QLocale::system().toString( static_cast<const QgsPoint *>( feature->geometry().geometry() )->m(), 'g', 10 );
+      str = QLocale::system().toString( static_cast<const QgsPoint *>( feature->geometry().constGet() )->m(), 'g', 10 );
       derivedAttributes.insert( QStringLiteral( "M" ), str );
     }
   }
diff --git a/src/providers/grass/qgsgrassprovider.cpp b/src/providers/grass/qgsgrassprovider.cpp
index d89e761b1fa..a51d4daf93a 100644
--- a/src/providers/grass/qgsgrassprovider.cpp
+++ b/src/providers/grass/qgsgrassprovider.cpp
@@ -1206,7 +1206,7 @@ void QgsGrassProvider::onFeatureAdded( QgsFeatureId fid )
     }
     QgsFeature feature = mEditBuffer->addedFeatures().value( fid );
     QgsGeometry featureGeometry = feature.geometry();
-    geometry = featureGeometry.geometry();
+    geometry = featureGeometry.constGet();
     if ( !geometry )
     {
       QgsDebugMsg( "geometry is null" );
@@ -1222,7 +1222,7 @@ void QgsGrassProvider::onFeatureAdded( QgsFeatureId fid )
     if ( wkbType == QgsWkbTypes::Polygon )
     {
       QgsGeometry addedFeatureGeom = addedFeatures[fid].geometry();
-      const QgsPolygonV2 *polygon = dynamic_cast<const QgsPolygonV2 *>( addedFeatureGeom.geometry() );
+      const QgsPolygonV2 *polygon = dynamic_cast<const QgsPolygonV2 *>( addedFeatureGeom.constGet() );
       if ( polygon )
       {
         QgsLineString *lineString = polygon->exteriorRing()->curveToLine();
@@ -1662,7 +1662,7 @@ void QgsGrassProvider::onGeometryChanged( QgsFeatureId fid, const QgsGeometry &g
     }
   }
 
-  setPoints( mPoints, geom.geometry() );
+  setPoints( mPoints, geom.constGet() );
 
   mLayer->map()->lockReadWrite();
   // Vect_rewrite_line may delete/write the line with a new id
diff --git a/src/server/services/wfs/qgswfsgetfeature.cpp b/src/server/services/wfs/qgswfsgetfeature.cpp
index 487a8a7bbef..18df99fe5f3 100644
--- a/src/server/services/wfs/qgswfsgetfeature.cpp
+++ b/src/server/services/wfs/qgswfsgetfeature.cpp
@@ -1254,7 +1254,7 @@ namespace QgsWfs
         }
         else
         {
-          QgsAbstractGeometry *abstractGeom = geom.geometry();
+          const QgsAbstractGeometry *abstractGeom = geom.constGet();
           if ( abstractGeom )
           {
             gmlElem = abstractGeom->asGML2( doc, prec, "http://www.opengis.net/gml" );
@@ -1355,7 +1355,7 @@ namespace QgsWfs
         }
         else
         {
-          QgsAbstractGeometry *abstractGeom = geom.geometry();
+          const QgsAbstractGeometry *abstractGeom = geom.constGet();
           if ( abstractGeom )
           {
             gmlElem = abstractGeom->asGML3( doc, prec, "http://www.opengis.net/gml" );
diff --git a/src/server/services/wms/qgswmsrenderer.cpp b/src/server/services/wms/qgswmsrenderer.cpp
index 84618b37a39..4a2bab6044e 100644
--- a/src/server/services/wms/qgswmsrenderer.cpp
+++ b/src/server/services/wms/qgswmsrenderer.cpp
@@ -1613,13 +1613,13 @@ namespace QgsWms
 
             if ( segmentizeWktGeometry )
             {
-              QgsAbstractGeometry *abstractGeom = geom.geometry();
+              const QgsAbstractGeometry *abstractGeom = geom.constGet();
               if ( abstractGeom )
               {
                 if ( QgsWkbTypes::isCurvedType( abstractGeom->wkbType() ) )
                 {
                   QgsAbstractGeometry *segmentizedGeom = abstractGeom->segmentize();
-                  geom.setGeometry( segmentizedGeom );
+                  geom.set( segmentizedGeom );
                 }
               }
             }
diff --git a/tests/src/analysis/testqgsprocessing.cpp b/tests/src/analysis/testqgsprocessing.cpp
index 377476ffc3d..acf52cff358 100644
--- a/tests/src/analysis/testqgsprocessing.cpp
+++ b/tests/src/analysis/testqgsprocessing.cpp
@@ -1911,7 +1911,7 @@ void TestQgsProcessing::parameterExtent()
   QGSCOMPARENEAR( ext.yMinimum(),  30.151856, 0.01 );
   QGSCOMPARENEAR( ext.yMaximum(), 30.257289, 0.01 );
   QgsGeometry gExt = QgsProcessingParameters::parameterAsExtentGeometry( def.get(), params, context, QgsCoordinateReferenceSystem( "EPSG:4326" ) );
-  QCOMPARE( gExt.geometry()->vertexCount(), 85 );
+  QCOMPARE( gExt.constGet()->vertexCount(), 85 );
   ext = gExt.boundingBox();
   QGSCOMPARENEAR( ext.xMinimum(), 17.924273, 0.01 );
   QGSCOMPARENEAR( ext.xMaximum(), 18.045658, 0.01 );
@@ -1948,7 +1948,7 @@ void TestQgsProcessing::parameterExtent()
   QGSCOMPARENEAR( ext.yMinimum(),  244963, 100 );
   QGSCOMPARENEAR( ext.yMaximum(), 490287, 100 );
   gExt = QgsProcessingParameters::parameterAsExtentGeometry( def.get(), params, context, QgsCoordinateReferenceSystem( "EPSG:3785" ) );
-  QCOMPARE( gExt.geometry()->vertexCount(), 85 );
+  QCOMPARE( gExt.constGet()->vertexCount(), 85 );
   ext = gExt.boundingBox();
   QGSCOMPARENEAR( ext.xMinimum(), 122451, 100 );
   QGSCOMPARENEAR( ext.xMaximum(), 367354, 100 );
@@ -1998,7 +1998,7 @@ void TestQgsProcessing::parameterExtent()
 
   // as reprojected geometry
   gExt = QgsProcessingParameters::parameterAsExtentGeometry( def.get(), params, context, QgsCoordinateReferenceSystem( "EPSG:3785" ) );
-  QCOMPARE( gExt.geometry()->vertexCount(), 85 );
+  QCOMPARE( gExt.constGet()->vertexCount(), 85 );
   ext = gExt.boundingBox();
   QGSCOMPARENEAR( ext.xMinimum(), 122451, 100 );
   QGSCOMPARENEAR( ext.xMaximum(), 367354, 100 );
diff --git a/tests/src/app/testqgisappclipboard.cpp b/tests/src/app/testqgisappclipboard.cpp
index 9ac8451864a..e662339bc58 100644
--- a/tests/src/app/testqgisappclipboard.cpp
+++ b/tests/src/app/testqgisappclipboard.cpp
@@ -205,14 +205,14 @@ void TestQgisAppClipboard::pasteWkt()
   QgsFeatureList features = mQgisApp->clipboard()->copyOf();
   QCOMPARE( features.length(), 2 );
   QVERIFY( features.at( 0 ).hasGeometry() && !features.at( 0 ).geometry().isNull() );
-  QCOMPARE( features.at( 0 ).geometry().geometry()->wkbType(), QgsWkbTypes::Point );
+  QCOMPARE( features.at( 0 ).geometry().constGet()->wkbType(), QgsWkbTypes::Point );
   QgsGeometry featureGeom = features.at( 0 ).geometry();
-  const QgsPoint *point = dynamic_cast< QgsPoint * >( featureGeom.geometry() );
+  const QgsPoint *point = dynamic_cast< const QgsPoint * >( featureGeom.constGet() );
   QCOMPARE( point->x(), 125.0 );
   QCOMPARE( point->y(), 10.0 );
   QVERIFY( features.at( 1 ).hasGeometry() && !features.at( 1 ).geometry().isNull() );
-  QCOMPARE( features.at( 1 ).geometry().geometry()->wkbType(), QgsWkbTypes::Point );
-  point = dynamic_cast< QgsPoint * >( features.at( 1 ).geometry().geometry() );
+  QCOMPARE( features.at( 1 ).geometry().constGet()->wkbType(), QgsWkbTypes::Point );
+  point = dynamic_cast< const QgsPoint * >( features.at( 1 ).geometry().constGet() );
   QCOMPARE( point->x(), 111.0 );
   QCOMPARE( point->y(), 30.0 );
 
@@ -224,15 +224,15 @@ void TestQgisAppClipboard::pasteWkt()
   QCOMPARE( features.length(), 2 );
 
   QVERIFY( features.at( 0 ).hasGeometry() && !features.at( 0 ).geometry().isNull() );
-  QCOMPARE( features.at( 0 ).geometry().geometry()->wkbType(), QgsWkbTypes::Point );
+  QCOMPARE( features.at( 0 ).geometry().constGet()->wkbType(), QgsWkbTypes::Point );
   featureGeom = features.at( 0 ).geometry();
-  point = dynamic_cast< QgsPoint * >( featureGeom.geometry() );
+  point = dynamic_cast< const QgsPoint * >( featureGeom.constGet() );
   QCOMPARE( point->x(), 111.0 );
   QCOMPARE( point->y(), 30.0 );
 
   QVERIFY( features.at( 1 ).hasGeometry() && !features.at( 1 ).geometry().isNull() );
-  QCOMPARE( features.at( 1 ).geometry().geometry()->wkbType(), QgsWkbTypes::Point );
-  point = dynamic_cast< QgsPoint * >( features.at( 1 ).geometry().geometry() );
+  QCOMPARE( features.at( 1 ).geometry().constGet()->wkbType(), QgsWkbTypes::Point );
+  point = dynamic_cast< const QgsPoint * >( features.at( 1 ).geometry().constGet() );
   QCOMPARE( point->x(), 125.0 );
   QCOMPARE( point->y(), 10.0 );
 
@@ -251,9 +251,9 @@ void TestQgisAppClipboard::pasteGeoJson()
   QgsFeatureList features = mQgisApp->clipboard()->copyOf( fields );
   QCOMPARE( features.length(), 1 );
   QVERIFY( features.at( 0 ).hasGeometry() && !features.at( 0 ).geometry().isNull() );
-  QCOMPARE( features.at( 0 ).geometry().geometry()->wkbType(), QgsWkbTypes::Point );
+  QCOMPARE( features.at( 0 ).geometry().constGet()->wkbType(), QgsWkbTypes::Point );
   QgsGeometry featureGeom = features.at( 0 ).geometry();
-  const QgsPoint *point = dynamic_cast< QgsPoint * >( featureGeom.geometry() );
+  const QgsPoint *point = dynamic_cast< const QgsPoint * >( featureGeom.constGet() );
   QCOMPARE( point->x(), 125.0 );
   QCOMPARE( point->y(), 10.0 );
   QCOMPARE( features.at( 0 ).attribute( "name" ).toString(), QString( "Dinagat Islands" ) );
diff --git a/tests/src/core/testqgsconnectionpool.cpp b/tests/src/core/testqgsconnectionpool.cpp
index 57c604132a5..df4f528e909 100644
--- a/tests/src/core/testqgsconnectionpool.cpp
+++ b/tests/src/core/testqgsconnectionpool.cpp
@@ -116,7 +116,7 @@ void TestQgsConnectionPool::layersFromSameDatasetGPX()
   for ( int i = 0, n = layer1Features.count(); i < n; ++i )
   {
     QgsGeometry featureGeom = layer1Features[i].geometry();
-    const QgsPoint *geom = dynamic_cast<const QgsPoint *>( featureGeom.geometry() );
+    const QgsPoint *geom = dynamic_cast<const QgsPoint *>( featureGeom.constGet() );
     QVERIFY( geom );
     QVERIFY( qFuzzyCompare( geom->x(), i ) );
     QVERIFY( qFuzzyCompare( geom->y(), i ) );
@@ -124,7 +124,7 @@ void TestQgsConnectionPool::layersFromSameDatasetGPX()
   for ( int i = 0, n = layer2Features.count(); i < n; ++i )
   {
     QgsGeometry featureGeom = layer2Features[i].geometry();
-    const QgsLineString *geom = dynamic_cast<const QgsLineString *>( featureGeom.geometry() );
+    const QgsLineString *geom = dynamic_cast<const QgsLineString *>( featureGeom.constGet() );
     QVERIFY( geom );
     int nVtx = geom->vertexCount();
     QVERIFY( nVtx == nRoutePts );
diff --git a/tests/src/core/testqgsgeometry.cpp b/tests/src/core/testqgsgeometry.cpp
index b23aab44572..63514bfb57c 100644
--- a/tests/src/core/testqgsgeometry.cpp
+++ b/tests/src/core/testqgsgeometry.cpp
@@ -322,74 +322,74 @@ void TestQgsGeometry::copy()
 {
   //create a point geometry
   QgsGeometry original( new QgsPoint( 1.0, 2.0 ) );
-  QCOMPARE( original.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
-  QCOMPARE( original.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
+  QCOMPARE( original.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
+  QCOMPARE( original.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
 
   //implicitly shared copy
   QgsGeometry copy( original );
-  QCOMPARE( copy.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
-  QCOMPARE( copy.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
+  QCOMPARE( copy.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
+  QCOMPARE( copy.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
 
   //trigger a detach
-  copy.setGeometry( new QgsPoint( 3.0, 4.0 ) );
-  QCOMPARE( copy.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 3.0 );
-  QCOMPARE( copy.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 4.0 );
+  copy.set( new QgsPoint( 3.0, 4.0 ) );
+  QCOMPARE( copy.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 3.0 );
+  QCOMPARE( copy.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 4.0 );
 
   //make sure original was untouched
-  QCOMPARE( original.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
-  QCOMPARE( original.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
+  QCOMPARE( original.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
+  QCOMPARE( original.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
 }
 
 void TestQgsGeometry::assignment()
 {
   //create a point geometry
   QgsGeometry original( new QgsPoint( 1.0, 2.0 ) );
-  QCOMPARE( original.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
-  QCOMPARE( original.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
+  QCOMPARE( original.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
+  QCOMPARE( original.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
 
   //assign to implicitly shared copy
   QgsGeometry copy;
   copy = original;
-  QCOMPARE( copy.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
-  QCOMPARE( copy.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
+  QCOMPARE( copy.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
+  QCOMPARE( copy.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
 
   //trigger a detach
-  copy.setGeometry( new QgsPoint( 3.0, 4.0 ) );
-  QCOMPARE( copy.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 3.0 );
-  QCOMPARE( copy.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 4.0 );
+  copy.set( new QgsPoint( 3.0, 4.0 ) );
+  QCOMPARE( copy.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 3.0 );
+  QCOMPARE( copy.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 4.0 );
 
   //make sure original was untouched
-  QCOMPARE( original.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
-  QCOMPARE( original.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
+  QCOMPARE( original.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
+  QCOMPARE( original.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
 }
 
 void TestQgsGeometry::asVariant()
 {
   //create a point geometry
   QgsGeometry original( new QgsPoint( 1.0, 2.0 ) );
-  QCOMPARE( original.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
-  QCOMPARE( original.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
+  QCOMPARE( original.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
+  QCOMPARE( original.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
 
   //convert to and from a QVariant
   QVariant var = QVariant::fromValue( original );
   QVERIFY( var.isValid() );
 
   QgsGeometry fromVar = qvariant_cast<QgsGeometry>( var );
-  QCOMPARE( fromVar.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
-  QCOMPARE( fromVar.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
+  QCOMPARE( fromVar.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
+  QCOMPARE( fromVar.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
 
   //also check copying variant
   QVariant var2 = var;
   QVERIFY( var2.isValid() );
   QgsGeometry fromVar2 = qvariant_cast<QgsGeometry>( var2 );
-  QCOMPARE( fromVar2.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
-  QCOMPARE( fromVar2.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
+  QCOMPARE( fromVar2.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
+  QCOMPARE( fromVar2.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
 
   //modify original and check detachment
-  original.setGeometry( new QgsPoint( 3.0, 4.0 ) );
+  original.set( new QgsPoint( 3.0, 4.0 ) );
   QgsGeometry fromVar3 = qvariant_cast<QgsGeometry>( var );
-  QCOMPARE( fromVar3.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
-  QCOMPARE( fromVar3.geometry()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
+  QCOMPARE( fromVar3.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).x(), 1.0 );
+  QCOMPARE( fromVar3.constGet()->vertexAt( QgsVertexId( 0, 0, 0 ) ).y(), 2.0 );
 }
 
 void TestQgsGeometry::isEmpty()
@@ -397,10 +397,10 @@ void TestQgsGeometry::isEmpty()
   QgsGeometry geom;
   QVERIFY( geom.isNull() );
 
-  geom.setGeometry( new QgsPoint( 1.0, 2.0 ) );
+  geom.set( new QgsPoint( 1.0, 2.0 ) );
   QVERIFY( !geom.isNull() );
 
-  geom.setGeometry( 0 );
+  geom.set( 0 );
   QVERIFY( geom.isNull() );
 
   QgsGeometryCollection collection;
@@ -412,10 +412,10 @@ void TestQgsGeometry::operatorBool()
   QgsGeometry geom;
   QVERIFY( !geom );
 
-  geom.setGeometry( new QgsPoint( 1.0, 2.0 ) );
+  geom.set( new QgsPoint( 1.0, 2.0 ) );
   QVERIFY( geom );
 
-  geom.setGeometry( 0 );
+  geom.set( 0 );
   QVERIFY( !geom );
 }
 
@@ -15099,10 +15099,10 @@ void TestQgsGeometry::intersectionCheck1()
 {
   QVERIFY( mpPolygonGeometryA.intersects( mpPolygonGeometryB ) );
 
-  std::unique_ptr< QgsGeometryEngine > engine( QgsGeometry::createGeometryEngine( mpPolygonGeometryA.geometry() ) );
-  QVERIFY( engine->intersects( mpPolygonGeometryB.geometry() ) );
+  std::unique_ptr< QgsGeometryEngine > engine( QgsGeometry::createGeometryEngine( mpPolygonGeometryA.constGet() ) );
+  QVERIFY( engine->intersects( mpPolygonGeometryB.constGet() ) );
   engine->prepareGeometry();
-  QVERIFY( engine->intersects( mpPolygonGeometryB.geometry() ) );
+  QVERIFY( engine->intersects( mpPolygonGeometryB.constGet() ) );
 
   // should be a single polygon as A intersect B
   QgsGeometry mypIntersectionGeometry  =  mpPolygonGeometryA.intersection( mpPolygonGeometryB );
@@ -15389,7 +15389,7 @@ void TestQgsGeometry::dataStream()
   ds.device()->seek( 0 );
   ds >> resultGeometry;
 
-  QCOMPARE( geom.geometry()->asWkt(), resultGeometry.geometry()->asWkt() );
+  QCOMPARE( geom.constGet()->asWkt(), resultGeometry.constGet()->asWkt() );
 
   //also test with geometry without data
   std::unique_ptr<QgsGeometry> emptyGeom( new QgsGeometry() );
@@ -15863,7 +15863,7 @@ void TestQgsGeometry::minimalEnclosingCircle()
   result = geomTest.minimalEnclosingCircle( center, radius );
   QCOMPARE( center, QgsPointXY( 5, 5 ) );
   QCOMPARE( radius, 0.0 );
-  resultTest.setGeometry( QgsCircle( QgsPoint( center ), radius ).toPolygon( 36 ) );
+  resultTest.set( QgsCircle( QgsPoint( center ), radius ).toPolygon( 36 ) );
   QCOMPARE( result, resultTest );
 
   // case 2
@@ -15871,35 +15871,35 @@ void TestQgsGeometry::minimalEnclosingCircle()
   result = geomTest.minimalEnclosingCircle( center, radius );
   QGSCOMPARENEARPOINT( center, QgsPointXY( 5, 6 ), 0.0001 );
   QGSCOMPARENEAR( radius, sqrt( 2 ) * 2, 0.0001 );
-  resultTest.setGeometry( QgsCircle( QgsPoint( center ), radius ).toPolygon( 36 ) );
+  resultTest.set( QgsCircle( QgsPoint( center ), radius ).toPolygon( 36 ) );
   QCOMPARE( result, resultTest );
 
   geomTest = QgsGeometry::fromWkt( QStringLiteral( "LINESTRING( 0 5, 2 2, 0 -5, -1 -1 )" ) );
   result = geomTest.minimalEnclosingCircle( center, radius );
   QGSCOMPARENEARPOINT( center, QgsPointXY( 0, 0 ), 0.0001 );
   QGSCOMPARENEAR( radius, 5, 0.0001 );
-  resultTest.setGeometry( QgsCircle( QgsPoint( center ), radius ).toPolygon( 36 ) );
+  resultTest.set( QgsCircle( QgsPoint( center ), radius ).toPolygon( 36 ) );
   QCOMPARE( result, resultTest );
 
   geomTest = QgsGeometry::fromWkt( QStringLiteral( "MULTIPOINT( 0 5, 2 2, 0 -5, -1 -1 )" ) );
   result = geomTest.minimalEnclosingCircle( center, radius );
   QGSCOMPARENEARPOINT( center, QgsPointXY( 0, 0 ), 0.0001 );
   QGSCOMPARENEAR( radius, 5, 0.0001 );
-  resultTest.setGeometry( QgsCircle( QgsPoint( center ), radius ).toPolygon( 36 ) );
+  resultTest.set( QgsCircle( QgsPoint( center ), radius ).toPolygon( 36 ) );
   QCOMPARE( result, resultTest );
 
   geomTest = QgsGeometry::fromWkt( QStringLiteral( "POLYGON(( 0 5, 2 2, 0 -5, -1 -1 ))" ) );
   result = geomTest.minimalEnclosingCircle( center, radius );
   QGSCOMPARENEARPOINT( center, QgsPointXY( 0, 0 ), 0.0001 );
   QGSCOMPARENEAR( radius, 5, 0.0001 );
-  resultTest.setGeometry( QgsCircle( QgsPoint( center ), radius ).toPolygon( 36 ) );
+  resultTest.set( QgsCircle( QgsPoint( center ), radius ).toPolygon( 36 ) );
   QCOMPARE( result, resultTest );
 
   geomTest = QgsGeometry::fromWkt( QStringLiteral( "MULTIPOINT( 0 5, 0 -5, 0 0 )" ) );
   result = geomTest.minimalEnclosingCircle( center, radius );
   QGSCOMPARENEARPOINT( center, QgsPointXY( 0, 0 ), 0.0001 );
   QGSCOMPARENEAR( radius, 5, 0.0001 );
-  resultTest.setGeometry( QgsCircle( QgsPoint( center ), radius ).toPolygon( 36 ) );
+  resultTest.set( QgsCircle( QgsPoint( center ), radius ).toPolygon( 36 ) );
   QCOMPARE( result, resultTest );
 
   // case 3
@@ -15907,7 +15907,7 @@ void TestQgsGeometry::minimalEnclosingCircle()
   result = geomTest.minimalEnclosingCircle( center, radius );
   QGSCOMPARENEARPOINT( center, QgsPointXY( 0.8333, 0.8333 ), 0.0001 );
   QGSCOMPARENEAR( radius, 5.8926, 0.0001 );
-  resultTest.setGeometry( QgsCircle( QgsPoint( center ), radius ).toPolygon( 36 ) );
+  resultTest.set( QgsCircle( QgsPoint( center ), radius ).toPolygon( 36 ) );
   QCOMPARE( result, resultTest );
 
 }
diff --git a/tests/src/core/testqgsogrutils.cpp b/tests/src/core/testqgsogrutils.cpp
index 8376dfebbdf..228862f936f 100644
--- a/tests/src/core/testqgsogrutils.cpp
+++ b/tests/src/core/testqgsogrutils.cpp
@@ -97,8 +97,8 @@ void TestQgsOgrUtils::ogrGeometryToQgsGeometry()
 
   QgsGeometry geom = QgsOgrUtils::ogrGeometryToQgsGeometry( ogrGeom );
   QVERIFY( !geom.isNull() );
-  QCOMPARE( geom.geometry()->wkbType(), QgsWkbTypes::LineString );
-  QCOMPARE( geom.geometry()->nCoordinates(), 71 );
+  QCOMPARE( geom.constGet()->wkbType(), QgsWkbTypes::LineString );
+  QCOMPARE( geom.constGet()->nCoordinates(), 71 );
 
   OGR_F_Destroy( oFeat );
   OGR_DS_Destroy( hDS );
@@ -124,8 +124,8 @@ void TestQgsOgrUtils::readOgrFeatureGeometry()
 
   QgsOgrUtils::readOgrFeatureGeometry( oFeat, f );
   QVERIFY( f.hasGeometry() );
-  QCOMPARE( f.geometry().geometry()->wkbType(), QgsWkbTypes::LineString );
-  QCOMPARE( f.geometry().geometry()->nCoordinates(), 71 );
+  QCOMPARE( f.geometry().constGet()->wkbType(), QgsWkbTypes::LineString );
+  QCOMPARE( f.geometry().constGet()->nCoordinates(), 71 );
 
   OGR_F_Destroy( oFeat );
   OGR_DS_Destroy( hDS );
@@ -273,8 +273,8 @@ void TestQgsOgrUtils::readOgrFeature()
   QCOMPARE( f.attribute( "datetime_field" ), QVariant( QDateTime( QDate( 2005, 3, 5 ), QTime( 6, 45, 0 ) ) ) );
   QCOMPARE( f.attribute( "string_field" ), QVariant( "a string" ) );
   QVERIFY( f.hasGeometry() );
-  QCOMPARE( f.geometry().geometry()->wkbType(), QgsWkbTypes::LineString );
-  QCOMPARE( f.geometry().geometry()->nCoordinates(), 71 );
+  QCOMPARE( f.geometry().constGet()->wkbType(), QgsWkbTypes::LineString );
+  QCOMPARE( f.geometry().constGet()->nCoordinates(), 71 );
 
   OGR_F_Destroy( oFeat );
   OGR_DS_Destroy( hDS );
@@ -331,9 +331,9 @@ void TestQgsOgrUtils::stringToFeatureList()
   features = QgsOgrUtils::stringToFeatureList( QStringLiteral( "{\n\"type\": \"Feature\",\"geometry\": {\"type\": \"Point\",\"coordinates\": [125, 10]},\"properties\": {\"name\": \"Dinagat Islands\"}}" ), fields, QTextCodec::codecForName( "System" ) );
   QCOMPARE( features.length(), 1 );
   QVERIFY( features.at( 0 ).hasGeometry() && !features.at( 0 ).geometry().isNull() );
-  QCOMPARE( features.at( 0 ).geometry().geometry()->wkbType(), QgsWkbTypes::Point );
+  QCOMPARE( features.at( 0 ).geometry().constGet()->wkbType(), QgsWkbTypes::Point );
   QgsGeometry featureGeom = features.at( 0 ).geometry();
-  const QgsPoint *point = dynamic_cast< QgsPoint * >( featureGeom.geometry() );
+  const QgsPoint *point = dynamic_cast< const QgsPoint * >( featureGeom.constGet() );
   QCOMPARE( point->x(), 125.0 );
   QCOMPARE( point->y(), 10.0 );
   QCOMPARE( features.at( 0 ).attribute( "name" ).toString(), QString( "Dinagat Islands" ) );
@@ -343,16 +343,16 @@ void TestQgsOgrUtils::stringToFeatureList()
              " {\n\"type\": \"Feature\",\"geometry\": {\"type\": \"Point\",\"coordinates\": [110, 20]},\"properties\": {\"name\": \"Henry Gale Island\"}}]}", fields, QTextCodec::codecForName( "System" ) );
   QCOMPARE( features.length(), 2 );
   QVERIFY( features.at( 0 ).hasGeometry() && !features.at( 0 ).geometry().isNull() );
-  QCOMPARE( features.at( 0 ).geometry().geometry()->wkbType(), QgsWkbTypes::Point );
+  QCOMPARE( features.at( 0 ).geometry().constGet()->wkbType(), QgsWkbTypes::Point );
   featureGeom = features.at( 0 ).geometry();
-  point = dynamic_cast< QgsPoint * >( featureGeom.geometry() );
+  point = dynamic_cast< const QgsPoint * >( featureGeom.constGet() );
   QCOMPARE( point->x(), 125.0 );
   QCOMPARE( point->y(), 10.0 );
   QCOMPARE( features.at( 0 ).attribute( "name" ).toString(), QString( "Dinagat Islands" ) );
   QVERIFY( features.at( 1 ).hasGeometry() && !features.at( 1 ).geometry().isNull() );
-  QCOMPARE( features.at( 1 ).geometry().geometry()->wkbType(), QgsWkbTypes::Point );
+  QCOMPARE( features.at( 1 ).geometry().constGet()->wkbType(), QgsWkbTypes::Point );
   featureGeom = features.at( 1 ).geometry();
-  point = dynamic_cast< QgsPoint * >( featureGeom.geometry() );
+  point = dynamic_cast< const QgsPoint * >( featureGeom.constGet() );
   QCOMPARE( point->x(), 110.0 );
   QCOMPARE( point->y(), 20.0 );
   QCOMPARE( features.at( 1 ).attribute( "name" ).toString(), QString( "Henry Gale Island" ) );
diff --git a/tests/src/core/testqgspointlocator.cpp b/tests/src/core/testqgspointlocator.cpp
index 93272539387..8513f81951a 100644
--- a/tests/src/core/testqgspointlocator.cpp
+++ b/tests/src/core/testqgspointlocator.cpp
@@ -286,7 +286,7 @@ class TestQgsPointLocator : public QObject
       QgsVectorLayer *vlEmptyGeom = new QgsVectorLayer( QStringLiteral( "Polygon" ), QStringLiteral( "x" ), QStringLiteral( "memory" ) );
       QgsFeature ff( 0 );
       QgsGeometry g;
-      g.setGeometry( new QgsPolygonV2() );
+      g.set( new QgsPolygonV2() );
       ff.setGeometry( g );
       QgsFeatureList flist;
       flist << ff;
diff --git a/tests/src/geometry_checker/testqgsgeometrychecks.cpp b/tests/src/geometry_checker/testqgsgeometrychecks.cpp
index 4741ba0ebe1..89281b8108d 100644
--- a/tests/src/geometry_checker/testqgsgeometrychecks.cpp
+++ b/tests/src/geometry_checker/testqgsgeometrychecks.cpp
@@ -141,21 +141,21 @@ void TestQgsGeometryChecks::testAngleCheck()
   int n1, n2;
 
   context->featurePools[errs1[0]->layerId()]->get( errs1[0]->featureId(), f );
-  n1 = f.geometry().geometry()->vertexCount( errs1[0]->vidx().part, errs1[0]->vidx().ring );
+  n1 = f.geometry().constGet()->vertexCount( errs1[0]->vidx().part, errs1[0]->vidx().ring );
   QVERIFY( fixCheckError( errs1[0],
                           QgsGeometryAngleCheck::DeleteNode, QgsGeometryCheckError::StatusFixed,
   {{errs1[0]->layerId(), errs1[0]->featureId(), QgsGeometryCheck::ChangeNode, QgsGeometryCheck::ChangeRemoved, errs1[0]->vidx()}} ) );
   context->featurePools[errs1[0]->layerId()]->get( errs1[0]->featureId(), f );
-  n2 = f.geometry().geometry()->vertexCount( errs1[0]->vidx().part, errs1[0]->vidx().ring );
+  n2 = f.geometry().constGet()->vertexCount( errs1[0]->vidx().part, errs1[0]->vidx().ring );
   QCOMPARE( n1, n2 + 1 );
 
   context->featurePools[errs2[0]->layerId()]->get( errs2[0]->featureId(), f );
-  n1 = f.geometry().geometry()->vertexCount( errs2[0]->vidx().part, errs2[0]->vidx().ring );
+  n1 = f.geometry().constGet()->vertexCount( errs2[0]->vidx().part, errs2[0]->vidx().ring );
   QVERIFY( fixCheckError( errs2[0],
                           QgsGeometryAngleCheck::DeleteNode, QgsGeometryCheckError::StatusFixed,
   {{errs2[0]->layerId(), errs2[0]->featureId(), QgsGeometryCheck::ChangeNode, QgsGeometryCheck::ChangeRemoved, errs2[0]->vidx()}} ) );
   context->featurePools[errs2[0]->layerId()]->get( errs2[0]->featureId(), f );
-  n2 = f.geometry().geometry()->vertexCount( errs2[0]->vidx().part, errs2[0]->vidx().ring );
+  n2 = f.geometry().constGet()->vertexCount( errs2[0]->vidx().part, errs2[0]->vidx().ring );
   QCOMPARE( n1, n2 + 1 );
 
   // Test change tracking
@@ -455,12 +455,12 @@ void TestQgsGeometryChecks::testDuplicateNodesCheck()
   QgsFeature f;
 
   context->featurePools[errs1[0]->layerId()]->get( errs1[0]->featureId(), f );
-  int n1 = f.geometry().geometry()->vertexCount( errs1[0]->vidx().part, errs1[0]->vidx().ring );
+  int n1 = f.geometry().constGet()->vertexCount( errs1[0]->vidx().part, errs1[0]->vidx().ring );
   QVERIFY( fixCheckError( errs1[0],
                           QgsGeometryDuplicateNodesCheck::RemoveDuplicates, QgsGeometryCheckError::StatusFixed,
   {{errs1[0]->layerId(), errs1[0]->featureId(), QgsGeometryCheck::ChangeNode, QgsGeometryCheck::ChangeRemoved, errs1[0]->vidx()}} ) );
   context->featurePools[errs1[0]->layerId()]->get( errs1[0]->featureId(), f );
-  int n2 = f.geometry().geometry()->vertexCount( errs1[0]->vidx().part, errs1[0]->vidx().ring );
+  int n2 = f.geometry().constGet()->vertexCount( errs1[0]->vidx().part, errs1[0]->vidx().ring );
   QCOMPARE( n1, n2 + 1 );
 
   cleanupTestContext( context );
@@ -562,7 +562,7 @@ void TestQgsGeometryChecks::testHoleCheck()
     {errs1[0]->layerId(), errs1[0]->featureId(), QgsGeometryCheck::ChangeRing, QgsGeometryCheck::ChangeRemoved, QgsVertexId( 0, 1 )}
   } ) );
   context->featurePools[errs1[0]->layerId()]->get( errs1[0]->featureId(), f );
-  QVERIFY( f.geometry().geometry()->ringCount( 0 ) == 1 );
+  QVERIFY( f.geometry().constGet()->ringCount( 0 ) == 1 );
 
   cleanupTestContext( context );
 }
@@ -867,11 +867,11 @@ void TestQgsGeometryChecks::testSelfIntersectionCheck()
     {errs1[0]->layerId(), nextId, QgsGeometryCheck::ChangeFeature, QgsGeometryCheck::ChangeAdded, QgsVertexId()}
   } ) );
   context->featurePools[errs1[0]->layerId()]->get( errs1[0]->featureId(), f );
-  QCOMPARE( f.geometry().geometry()->partCount(), 1 );
-  QCOMPARE( f.geometry().geometry()->vertexCount(), 4 );
+  QCOMPARE( f.geometry().constGet()->partCount(), 1 );
+  QCOMPARE( f.geometry().constGet()->vertexCount(), 4 );
   context->featurePools[errs1[0]->layerId()]->get( nextId, f );
-  QCOMPARE( f.geometry().geometry()->partCount(), 1 );
-  QCOMPARE( f.geometry().geometry()->vertexCount(), 6 );
+  QCOMPARE( f.geometry().constGet()->partCount(), 1 );
+  QCOMPARE( f.geometry().constGet()->vertexCount(), 6 );
 
   QVERIFY( fixCheckError( errs2[0],
                           QgsGeometrySelfIntersectionCheck::ToMultiObject, QgsGeometryCheckError::StatusFixed,
@@ -881,9 +881,9 @@ void TestQgsGeometryChecks::testSelfIntersectionCheck()
     {errs2[0]->layerId(), errs2[0]->featureId(), QgsGeometryCheck::ChangePart, QgsGeometryCheck::ChangeAdded, QgsVertexId( 1 )}
   } ) );
   context->featurePools[errs2[0]->layerId()]->get( errs2[0]->featureId(), f );
-  QCOMPARE( f.geometry().geometry()->partCount(), 2 );
-  QCOMPARE( f.geometry().geometry()->vertexCount( 0 ), 4 );
-  QCOMPARE( f.geometry().geometry()->vertexCount( 1 ), 5 );
+  QCOMPARE( f.geometry().constGet()->partCount(), 2 );
+  QCOMPARE( f.geometry().constGet()->vertexCount( 0 ), 4 );
+  QCOMPARE( f.geometry().constGet()->vertexCount( 1 ), 5 );
 
   nextId = context->featurePools[errs3[0]->layerId()]->getLayer()->featureCount();
   QVERIFY( fixCheckError( errs3[0],
@@ -893,11 +893,11 @@ void TestQgsGeometryChecks::testSelfIntersectionCheck()
     {errs3[0]->layerId(), nextId, QgsGeometryCheck::ChangeFeature, QgsGeometryCheck::ChangeAdded, QgsVertexId()}
   } ) );
   context->featurePools[errs3[0]->layerId()]->get( errs3[0]->featureId(), f );
-  QCOMPARE( f.geometry().geometry()->partCount(), 1 );
-  QCOMPARE( f.geometry().geometry()->vertexCount(), 6 );
+  QCOMPARE( f.geometry().constGet()->partCount(), 1 );
+  QCOMPARE( f.geometry().constGet()->vertexCount(), 6 );
   context->featurePools[errs3[0]->layerId()]->get( nextId, f );
-  QCOMPARE( f.geometry().geometry()->partCount(), 1 );
-  QCOMPARE( f.geometry().geometry()->vertexCount(), 4 );
+  QCOMPARE( f.geometry().constGet()->partCount(), 1 );
+  QCOMPARE( f.geometry().constGet()->vertexCount(), 4 );
 
   QVERIFY( fixCheckError( errs4[0],
                           QgsGeometrySelfIntersectionCheck::ToMultiObject, QgsGeometryCheckError::StatusFixed,
@@ -907,12 +907,12 @@ void TestQgsGeometryChecks::testSelfIntersectionCheck()
     {errs4[0]->layerId(), errs4[0]->featureId(), QgsGeometryCheck::ChangePart, QgsGeometryCheck::ChangeAdded, QgsVertexId( 1 )}
   } ) );
   context->featurePools[errs4[0]->layerId()]->get( errs4[0]->featureId(), f );
-  QCOMPARE( f.geometry().geometry()->partCount(), 2 );
-  QCOMPARE( f.geometry().geometry()->ringCount( 0 ), 1 );
-  QCOMPARE( f.geometry().geometry()->vertexCount( 0, 0 ), 5 );
-  QCOMPARE( f.geometry().geometry()->ringCount( 1 ), 2 );
-  QCOMPARE( f.geometry().geometry()->vertexCount( 1, 0 ), 5 );
-  QCOMPARE( f.geometry().geometry()->vertexCount( 1, 1 ), 5 );
+  QCOMPARE( f.geometry().constGet()->partCount(), 2 );
+  QCOMPARE( f.geometry().constGet()->ringCount( 0 ), 1 );
+  QCOMPARE( f.geometry().constGet()->vertexCount( 0, 0 ), 5 );
+  QCOMPARE( f.geometry().constGet()->ringCount( 1 ), 2 );
+  QCOMPARE( f.geometry().constGet()->vertexCount( 1, 0 ), 5 );
+  QCOMPARE( f.geometry().constGet()->vertexCount( 1, 1 ), 5 );
 
   // Test change tracking
   QgsGeometrySelfIntersectionCheckError *err = static_cast<QgsGeometrySelfIntersectionCheckError *>( errs4[0] );