Don't crash when deleting last vertex

Fix #12867

Backported to 2.8.3

Also preserves NULL rectangles in QgsRectangle::normalize()

Author: m-kuhn

src/core/qgspointlocator.cpp

@@ -632,11 +632,14 @@ bool QgsPointLocator::rebuildIndex( int maxFeaturesToIndex )
     QgsRectangle rect = *mExtent;
     if ( mTransform )
     {
-      try {
+      try
+      {
         rect = mTransform->transformBoundingBox( rect, QgsCoordinateTransform::ReverseTransform );
-      } catch (const QgsException& e) {
+      }
+      catch ( const QgsException& e )
+      {
         // See http://hub.qgis.org/issues/12634
-        QgsDebugMsg( QString("could not transform bounding box to map, skipping the snap filter (%1)").arg(e.what()) );
+        QgsDebugMsg( QString( "could not transform bounding box to map, skipping the snap filter (%1)" ).arg( e.what() ) );
       }
     }
     request.setFilterRect( rect );
@@ -650,11 +653,14 @@ bool QgsPointLocator::rebuildIndex( int maxFeaturesToIndex )
 
     if ( mTransform )
     {
-      try {
+      try
+      {
         f.geometry()->transform( *mTransform );
-      } catch (const QgsException& e) {
+      }
+      catch ( const QgsException& e )
+      {
         // See http://hub.qgis.org/issues/12634
-        QgsDebugMsg( QString("could not transform geometry to map, skipping the snap for it (%1)").arg(e.what()) );
+        QgsDebugMsg( QString( "could not transform geometry to map, skipping the snap for it (%1)" ).arg( e.what() ) );
         continue;
       }
     }
@@ -700,8 +706,8 @@ void QgsPointLocator::destroyIndex()
 
   mIsEmptyLayer = false;
 
-  foreach ( QgsGeometry* g, mGeoms )
-    delete g;
+  qDeleteAll( mGeoms );
+
   mGeoms.clear();
 }
 
@@ -722,18 +728,25 @@ void QgsPointLocator::onFeatureAdded( QgsFeatureId fid )
 
     if ( mTransform )
     {
-      try {
+      try
+      {
         f.geometry()->transform( *mTransform );
-      } catch (const QgsException& e) {
+      }
+      catch ( const QgsException& e )
+      {
         // See http://hub.qgis.org/issues/12634
-        QgsDebugMsg( QString("could not transform geometry to map, skipping the snap for it (%1)").arg(e.what()) );
+        QgsDebugMsg( QString( "could not transform geometry to map, skipping the snap for it (%1)" ).arg( e.what() ) );
         return;
       }
     }
 
-    SpatialIndex::Region r( rect2region( f.geometry()->boundingBox() ) );
-    mRTree->insertData( 0, 0, r, f.id() );
-    mGeoms[fid] = new QgsGeometry( *f.geometry() );
+    QgsRectangle bbox = f.geometry()->boundingBox();
+    if ( !bbox.isNull() )
+    {
+      SpatialIndex::Region r( rect2region( bbox ) );
+      mRTree->insertData( 0, 0, r, f.id() );
+      mGeoms[fid] = new QgsGeometry( *f.geometry() );
+    }
   }
 }
 

src/core/qgsrectangle.cpp

@@ -77,6 +77,9 @@ void QgsRectangle::set( double xmin_, double ymin_, double xmax_, double ymax_ )
 
 void QgsRectangle::normalize()
 {
+  if ( isNull() )
+    return;
+
   if ( xmin > xmax )
   {
     std::swap( xmin, xmax );