fix(qgsfeaturepool): better synchronization between cache and spatial…

… index

src/analysis/vector/geometry_checker/qgsfeaturepool.cpp

@@ -66,7 +66,21 @@ bool QgsFeaturePool::getFeature( QgsFeatureId id, QgsFeature &feature )
     }
     locker.changeMode( QgsReadWriteLocker::Write );
     mFeatureCache.insert( id, new QgsFeature( feature ) );
-    mIndex.addFeature( feature );
+
+    QgsGeometry indexGeom = mIndex.geometry( id );
+
+    // feature not in the index: add it
+    if ( indexGeom.isNull() )
+      mIndex.addFeature( feature );
+
+    // feature already in the index but with a different geometry (it has been evicted from the cache and externally modified):
+    // remove the old geometry and add the new one
+    else if ( !mIndex.geometry( id ).equals( feature.geometry() ) )
+    {
+      mIndex.deleteFeature( id, indexGeom.boundingBox() );
+      mIndex.addFeature( feature );
+    }
+
   }
   return true;
 }