Fix inadequate usage of nullptr

Author: m-kuhn

src/app/composer/qgsattributeselectiondialog.h

@@ -114,10 +114,10 @@ class QgsAttributeSelectionDialog: public QDialog, private Ui::QgsAttributeSelec
 {
     Q_OBJECT
   public:
-    QgsAttributeSelectionDialog( QgsComposerAttributeTableV2* table, QgsVectorLayer* vLayer, QWidget * parent = nullptr, Qt::WindowFlags f = nullptr );
+    QgsAttributeSelectionDialog( QgsComposerAttributeTableV2* table, QgsVectorLayer* vLayer, QWidget * parent = nullptr, Qt::WindowFlags f = 0 );
 
     //todo - remove for QGIS 3.0
-    QgsAttributeSelectionDialog( QgsComposerAttributeTable* table, QgsVectorLayer* vLayer, QWidget * parent = nullptr, Qt::WindowFlags f = nullptr );
+    QgsAttributeSelectionDialog( QgsComposerAttributeTable* table, QgsVectorLayer* vLayer, QWidget * parent = nullptr, Qt::WindowFlags f = 0 );
 
 
     ~QgsAttributeSelectionDialog();

src/app/composer/qgscomposerimageexportoptionsdialog.h

@@ -35,7 +35,7 @@ class QgsComposerImageExportOptionsDialog: public QDialog, private Ui::QgsCompos
      * @param parent parent widget
      * @param flags window flags
      */
-    QgsComposerImageExportOptionsDialog( QWidget* parent = nullptr, Qt::WindowFlags flags = nullptr );
+    QgsComposerImageExportOptionsDialog( QWidget* parent = nullptr, Qt::WindowFlags flags = 0 );
 
     ~QgsComposerImageExportOptionsDialog();
 

src/app/composer/qgscomposermanager.h

@@ -49,7 +49,7 @@ class QgsComposerManager: public QDialog, private Ui::QgsComposerManagerBase
 {
     Q_OBJECT
   public:
-    QgsComposerManager( QWidget * parent = nullptr, Qt::WindowFlags f = nullptr );
+    QgsComposerManager( QWidget * parent = nullptr, Qt::WindowFlags f = 0 );
     ~QgsComposerManager();
 
     void addTemplates( const QMap<QString, QString>& templates );

src/app/composer/qgscomposertablebackgroundcolorsdialog.h

@@ -38,7 +38,7 @@ class QgsComposerTableBackgroundColorsDialog: public QDialog, private Ui::QgsCom
      * @param parent parent widget
      * @param flags window flags
      */
-    QgsComposerTableBackgroundColorsDialog( QgsComposerTableV2* table, QWidget* parent = nullptr, Qt::WindowFlags flags = nullptr );
+    QgsComposerTableBackgroundColorsDialog( QgsComposerTableV2* table, QWidget* parent = nullptr, Qt::WindowFlags flags = 0 );
 
     ~QgsComposerTableBackgroundColorsDialog();
 

src/app/gps/qgsgpsinformationwidget.h

@@ -44,7 +44,7 @@ class QgsGPSInformationWidget: public QWidget, private Ui::QgsGPSInformationWidg
 {
     Q_OBJECT
   public:
-    QgsGPSInformationWidget( QgsMapCanvas * thepCanvas, QWidget * parent = nullptr, Qt::WindowFlags f = nullptr );
+    QgsGPSInformationWidget( QgsMapCanvas * thepCanvas, QWidget * parent = nullptr, Qt::WindowFlags f = 0 );
     ~QgsGPSInformationWidget();
 
   private slots:

src/app/ogr/qgsopenvectorlayerdialog.h

@@ -32,7 +32,7 @@ class QgsOpenVectorLayerDialog : public QDialog, private Ui::QgsOpenVectorLayerD
     Q_OBJECT
 
   public:
-    QgsOpenVectorLayerDialog( QWidget* parent = nullptr, Qt::WindowFlags fl = nullptr );
+    QgsOpenVectorLayerDialog( QWidget* parent = nullptr, Qt::WindowFlags fl = 0 );
     ~QgsOpenVectorLayerDialog();
     //! Opens a dialog to select a file datasource*/
     QStringList openFile();

src/app/ogr/qgsvectorlayersaveasdialog.h

@@ -41,8 +41,8 @@ class APP_EXPORT QgsVectorLayerSaveAsDialog : public QDialog, private Ui::QgsVec
       AllOptions = ~0
     };
 
-    QgsVectorLayerSaveAsDialog( long srsid, QWidget* parent = nullptr, Qt::WindowFlags fl = nullptr );
-    QgsVectorLayerSaveAsDialog( QgsVectorLayer *layer, int options = AllOptions, QWidget* parent = nullptr, Qt::WindowFlags fl = nullptr );
+    QgsVectorLayerSaveAsDialog( long srsid, QWidget* parent = nullptr, Qt::WindowFlags fl = 0 );
+    QgsVectorLayerSaveAsDialog( QgsVectorLayer *layer, int options = AllOptions, QWidget* parent = nullptr, Qt::WindowFlags fl = 0 );
     ~QgsVectorLayerSaveAsDialog();
 
     QString format() const;

src/app/qgisapp.cpp

@@ -1094,7 +1094,7 @@ QgisApp::QgisApp( QSplashScreen *splash, bool restorePlugins, bool skipVersionCh
 } // QgisApp ctor
 
 QgisApp::QgisApp()
-    : QMainWindow( nullptr, nullptr )
+    : QMainWindow( nullptr, 0 )
     , mProfiler( nullptr )
     , mStyleSheetBuilder( nullptr )
     , mActionPluginSeparator1( nullptr )
@@ -5955,7 +5955,7 @@ void QgisApp::saveAsRasterFile()
     fileWriter.setMaxTileHeight( d.maximumTileSizeY() );
   }
 
-  QProgressDialog pd( nullptr, tr( "Abort..." ), 0, 0 );
+  QProgressDialog pd( QString(), tr( "Abort..." ), 0, 0 );
   // Show the dialo immediately because cloning pipe can take some time (WCS)
   pd.setLabelText( tr( "Reading raster" ) );
   pd.setWindowTitle( tr( "Saving raster" ) );

src/app/qgsannotationwidget.h

@@ -29,7 +29,7 @@ class APP_EXPORT QgsAnnotationWidget: public QWidget, private Ui::QgsAnnotationW
 {
     Q_OBJECT
   public:
-    QgsAnnotationWidget( QgsAnnotationItem* item, QWidget * parent = nullptr, Qt::WindowFlags f = nullptr );
+    QgsAnnotationWidget( QgsAnnotationItem* item, QWidget * parent = nullptr, Qt::WindowFlags f = 0 );
     ~QgsAnnotationWidget();
 
     void apply();

src/app/qgsattributetabledialog.cpp

@@ -510,7 +510,7 @@ void QgsAttributeTableDialog::replaceSearchWidget( QWidget* oldw, QWidget* neww
 {
   mFilterLayout->removeWidget( oldw );
   oldw->setVisible( false );
-  mFilterLayout->addWidget( neww, 0, 0, nullptr );
+  mFilterLayout->addWidget( neww, 0, 0, 0 );
   neww->setVisible( true );
 }
 

src/app/qgsattributetabledialog.h

@@ -230,7 +230,7 @@ class QgsAttributeTableDock : public QgsDockWidget
     Q_OBJECT
 
   public:
-    QgsAttributeTableDock( const QString & title, QWidget * parent = nullptr, Qt::WindowFlags flags = nullptr );
+    QgsAttributeTableDock( const QString & title, QWidget * parent = nullptr, Qt::WindowFlags flags = 0 );
 
     virtual void closeEvent( QCloseEvent * ev ) override;
 };

src/app/qgscustomprojectiondialog.h

@@ -33,7 +33,7 @@ class APP_EXPORT QgsCustomProjectionDialog : public QDialog, private Ui::QgsCust
 {
     Q_OBJECT
   public:
-    QgsCustomProjectionDialog( QWidget *parent = nullptr, Qt::WindowFlags fl = nullptr );
+    QgsCustomProjectionDialog( QWidget *parent = nullptr, Qt::WindowFlags fl = 0 );
     ~QgsCustomProjectionDialog();
 
   public slots:

src/app/qgsdisplayangle.h

@@ -26,7 +26,7 @@ class APP_EXPORT QgsDisplayAngle: public QDialog, private Ui::QgsDisplayAngleBas
     Q_OBJECT
 
   public:
-    QgsDisplayAngle( QgsMapToolMeasureAngle * tool = nullptr, Qt::WindowFlags f = nullptr );
+    QgsDisplayAngle( QgsMapToolMeasureAngle * tool = nullptr, Qt::WindowFlags f = 0 );
     ~QgsDisplayAngle();
     /** Sets the measured angle value (in radians). The value is going to
       be converted to degrees / gon automatically if necessary*/

src/app/qgsdxfexportdialog.cpp

@@ -427,8 +427,8 @@ QgsDxfExportDialog::QgsDxfExportDialog( QWidget *parent, Qt::WindowFlags f )
   mTreeView->setEditTriggers( QAbstractItemView::AllEditTriggers );
   mTreeView->setItemDelegate( mFieldSelectorDelegate );
 
-  QgsLayerTreeModel *model = new QgsVectorLayerAndAttributeModel( mLayerTreeGroup, this );
-  model->setFlags( nullptr );
+  QgsLayerTreeModel* model = new QgsVectorLayerAndAttributeModel( mLayerTreeGroup, this );
+  model->setFlags( 0 );
   mTreeView->setModel( model );
   mTreeView->resizeColumnToContents( 0 );
   mTreeView->header()->show();

src/app/qgsdxfexportdialog.h

@@ -77,7 +77,7 @@ class QgsDxfExportDialog : public QDialog, private Ui::QgsDxfExportDialogBase
 {
     Q_OBJECT
   public:
-    QgsDxfExportDialog( QWidget * parent = nullptr, Qt::WindowFlags f = nullptr );
+    QgsDxfExportDialog( QWidget * parent = nullptr, Qt::WindowFlags f = 0 );
     ~QgsDxfExportDialog();
 
     QList< QPair<QgsVectorLayer *, int> > layers() const;

src/app/qgsformannotationdialog.h

@@ -24,7 +24,7 @@ class APP_EXPORT QgsFormAnnotationDialog: public QDialog, private Ui::QgsFormAnn
 {
     Q_OBJECT
   public:
-    QgsFormAnnotationDialog( QgsFormAnnotationItem* item, QWidget * parent = nullptr, Qt::WindowFlags f = nullptr );
+    QgsFormAnnotationDialog( QgsFormAnnotationItem* item, QWidget * parent = nullptr, Qt::WindowFlags f = 0 );
     ~QgsFormAnnotationDialog();
 
   private:

src/app/qgshtmlannotationdialog.h

@@ -24,7 +24,7 @@ class APP_EXPORT QgsHtmlAnnotationDialog: public QDialog, private Ui::QgsFormAnn
 {
     Q_OBJECT
   public:
-    QgsHtmlAnnotationDialog( QgsHtmlAnnotationItem* item, QWidget * parent = nullptr, Qt::WindowFlags f = nullptr );
+    QgsHtmlAnnotationDialog( QgsHtmlAnnotationItem* item, QWidget * parent = nullptr, Qt::WindowFlags f = 0 );
     ~QgsHtmlAnnotationDialog();
 
   private:

src/app/qgsidentifyresultsdialog.h

@@ -117,7 +117,7 @@ class APP_EXPORT QgsIdentifyResultsDialog: public QDialog, private Ui::QgsIdenti
 
     //! Constructor - takes it own copy of the QgsAttributeAction so
     // that it is independent of whoever created it.
-    QgsIdentifyResultsDialog( QgsMapCanvas *canvas, QWidget *parent = nullptr, Qt::WindowFlags f = nullptr );
+    QgsIdentifyResultsDialog( QgsMapCanvas *canvas, QWidget *parent = nullptr, Qt::WindowFlags f = 0 );
 
     ~QgsIdentifyResultsDialog();
 

src/app/qgsjoindialog.h

@@ -27,7 +27,7 @@ class APP_EXPORT QgsJoinDialog: public QDialog, private Ui::QgsJoinDialogBase
 {
     Q_OBJECT
   public:
-    QgsJoinDialog( QgsVectorLayer* layer, QList<QgsMapLayer*> alreadyJoinedLayers, QWidget * parent = nullptr, Qt::WindowFlags f = nullptr );
+    QgsJoinDialog( QgsVectorLayer* layer, QList<QgsMapLayer*> alreadyJoinedLayers, QWidget * parent = nullptr, Qt::WindowFlags f = 0 );
     ~QgsJoinDialog();
 
     /** Configure the dialog for an existing join */

src/app/qgslabelpropertydialog.h

@@ -29,7 +29,7 @@ class APP_EXPORT QgsLabelPropertyDialog: public QDialog, private Ui::QgsLabelPro
 {
     Q_OBJECT
   public:
-    QgsLabelPropertyDialog( const QString& layerId, const QString& providerId, int featureId, const QFont& labelFont, const QString& labelText, QWidget * parent = nullptr, Qt::WindowFlags f = nullptr );
+    QgsLabelPropertyDialog( const QString& layerId, const QString& providerId, int featureId, const QFont& labelFont, const QString& labelText, QWidget * parent = nullptr, Qt::WindowFlags f = 0 );
     ~QgsLabelPropertyDialog();
 
     /** Returns properties changed by the user*/

src/app/qgsmeasuredialog.h

@@ -33,7 +33,7 @@ class APP_EXPORT QgsMeasureDialog : public QDialog, private Ui::QgsMeasureBase
   public:
 
     //! Constructor
-    QgsMeasureDialog( QgsMeasureTool* tool, Qt::WindowFlags f = nullptr );
+    QgsMeasureDialog( QgsMeasureTool* tool, Qt::WindowFlags f = 0 );
 
     //! Save position
     void saveWindowLocation();

src/app/qgsmergeattributesdialog.h

@@ -42,7 +42,7 @@ class APP_EXPORT QgsMergeAttributesDialog: public QDialog, private Ui::QgsMergeA
     };
 
 
-    QgsMergeAttributesDialog( const QgsFeatureList& features, QgsVectorLayer* vl, QgsMapCanvas* canvas, QWidget * parent = nullptr, Qt::WindowFlags f = nullptr );
+    QgsMergeAttributesDialog( const QgsFeatureList& features, QgsVectorLayer* vl, QgsMapCanvas* canvas, QWidget * parent = nullptr, Qt::WindowFlags f = 0 );
     ~QgsMergeAttributesDialog();
 
     QgsAttributes mergedAttributes() const;

src/app/qgsoptions.cpp

@@ -1571,7 +1571,7 @@ void QgsOptions::editGdalDriver( const QString& driverName )
   if ( driverName.isEmpty() )
     return;
 
-  QgsDialog dlg( this, nullptr, QDialogButtonBox::Ok | QDialogButtonBox::Cancel );
+  QgsDialog dlg( this, 0, QDialogButtonBox::Ok | QDialogButtonBox::Cancel );
   QVBoxLayout *layout = dlg.layout();
   QString title = tr( "Create Options - %1 Driver" ).arg( driverName );
   if ( driverName == "_pyramids" )

src/app/qgsprojectlayergroupdialog.h

@@ -28,7 +28,7 @@ class APP_EXPORT QgsProjectLayerGroupDialog: public QDialog, private Ui::QgsProj
     Q_OBJECT
   public:
     /** Constructor. If a project file is given, the groups/layers are displayed directly and the file selection hidden*/
-    QgsProjectLayerGroupDialog( QWidget * parent = nullptr, const QString& projectFile = QString(), Qt::WindowFlags f = nullptr );
+    QgsProjectLayerGroupDialog( QWidget * parent = nullptr, const QString& projectFile = QString(), Qt::WindowFlags f = 0 );
     ~QgsProjectLayerGroupDialog();
 
     QStringList selectedGroups() const;

src/app/qgsrastercalcdialog.h

@@ -26,7 +26,7 @@ class APP_EXPORT QgsRasterCalcDialog: public QDialog, private Ui::QgsRasterCalcD
 {
     Q_OBJECT
   public:
-    QgsRasterCalcDialog( QWidget * parent = nullptr, Qt::WindowFlags f = nullptr );
+    QgsRasterCalcDialog( QWidget * parent = nullptr, Qt::WindowFlags f = 0 );
     ~QgsRasterCalcDialog();
 
     QString formulaString() const;

src/app/qgsselectbyformdialog.h

@@ -43,7 +43,7 @@ class APP_EXPORT QgsSelectByFormDialog : public QDialog
      */
     QgsSelectByFormDialog( QgsVectorLayer* layer,
                            const QgsAttributeEditorContext& context = QgsAttributeEditorContext(),
-                           QWidget* parent = nullptr, Qt::WindowFlags fl = nullptr );
+                           QWidget* parent = nullptr, Qt::WindowFlags fl = 0 );
 
     ~QgsSelectByFormDialog();
 

src/app/qgssnappingdialog.h

@@ -107,7 +107,7 @@ class QgsSnappingDock : public QgsDockWidget
     Q_OBJECT
 
   public:
-    QgsSnappingDock( const QString & title, QWidget * parent = nullptr, Qt::WindowFlags flags = nullptr );
+    QgsSnappingDock( const QString & title, QWidget * parent = nullptr, Qt::WindowFlags flags = 0 );
 
     virtual void closeEvent( QCloseEvent *e ) override;
 

src/app/qgsstatisticalsummarydockwidget.cpp

@@ -183,7 +183,7 @@ void QgsStatisticalSummaryDockWidget::updateNumericStatistics( bool selectedOnly
   }
 
   QList< QgsStatisticalSummary::Statistic > statsToDisplay;
-  QgsStatisticalSummary::Statistics statsToCalc = nullptr;
+  QgsStatisticalSummary::Statistics statsToCalc = 0;
   Q_FOREACH ( QgsStatisticalSummary::Statistic stat, mDisplayStats )
   {
     if ( mStatsActions.value( stat )->isChecked() )

src/app/qgssvgannotationdialog.h

@@ -27,7 +27,7 @@ class APP_EXPORT QgsSvgAnnotationDialog: public QDialog, private Ui::QgsFormAnno
 {
     Q_OBJECT
   public:
-    QgsSvgAnnotationDialog( QgsSvgAnnotationItem* item, QWidget * parent = nullptr, Qt::WindowFlags f = nullptr );
+    QgsSvgAnnotationDialog( QgsSvgAnnotationItem* item, QWidget * parent = nullptr, Qt::WindowFlags f = 0 );
     ~QgsSvgAnnotationDialog();
 
   private slots:

src/app/qgstextannotationdialog.h

@@ -27,7 +27,7 @@ class APP_EXPORT QgsTextAnnotationDialog: public QDialog, private Ui::QgsTextAnn
 {
     Q_OBJECT
   public:
-    QgsTextAnnotationDialog( QgsTextAnnotationItem* item, QWidget * parent = nullptr, Qt::WindowFlags f = nullptr );
+    QgsTextAnnotationDialog( QgsTextAnnotationItem* item, QWidget * parent = nullptr, Qt::WindowFlags f = 0 );
     ~QgsTextAnnotationDialog();
 
   private:

src/browser/qgsbrowser.h

@@ -30,7 +30,7 @@ class QgsBrowser : public QMainWindow, private Ui::QgsBrowserBase
 {
     Q_OBJECT
   public:
-    QgsBrowser( QWidget *parent = nullptr, const Qt::WindowFlags& flags = nullptr );
+    QgsBrowser( QWidget *parent = nullptr, const Qt::WindowFlags& flags = 0 );
     ~QgsBrowser();
 
     // Expand to given path

src/core/qgis.h

@@ -528,7 +528,7 @@ typedef unsigned long long qgssize;
 #endif
 
 #if defined(__clang__)
-#define FALLTHROUGH [[clang::fallthrough]]
+#define FALLTHROUGH //[[clang::fallthrough]]
 #else
 #define FALLTHROUGH
 #endif

src/core/qgsdiagramrendererv2.cpp

@@ -738,7 +738,7 @@ QList< QgsLayerTreeModelLegendNode* > QgsLinearlyInterpolatedDiagramRenderer::le
     Q_FOREACH ( double v, QgsSymbolLayerV2Utils::prettyBreaks( mInterpolationSettings.lowerValue, mInterpolationSettings.upperValue, 4 ) )
     {
       double size = mDiagram->legendSize( v, mSettings, mInterpolationSettings );
-      QgsLegendSymbolItemV2 si( mSizeLegendSymbol.data(), QString::number( v ), nullptr );
+      QgsLegendSymbolItemV2 si( mSizeLegendSymbol.data(), QString::number( v ), QString() );
       QgsMarkerSymbolV2 * s = static_cast<QgsMarkerSymbolV2 *>( si.symbol() );
       s->setSize( size );
       s->setSizeUnit( mSettings.sizeType );

src/core/qgslabelingenginev2.cpp

@@ -350,7 +350,7 @@ void QgsLabelingEngineV2::readSettingsFromProject()
   mCandLine = prj->readNumEntry( "PAL", "/CandidatesLine", 8, &saved );
   mCandPolygon = prj->readNumEntry( "PAL", "/CandidatesPolygon", 8, &saved );
 
-  mFlags = nullptr;
+  mFlags = 0;
   if ( prj->readBoolEntry( "PAL", "/ShowingCandidates", false, &saved ) ) mFlags |= DrawCandidates;
   if ( prj->readBoolEntry( "PAL", "/DrawRectOnly", false, &saved ) ) mFlags |= DrawLabelRectOnly;
   if ( prj->readBoolEntry( "PAL", "/ShowingShadowRects", false, &saved ) ) mFlags |= DrawShadowRects;

src/core/qgspaintenginehack.cpp

@@ -20,7 +20,7 @@
 // Hack to workaround Qt #5114 by disabling PatternTransform
 void QgsPaintEngineHack::fixFlags()
 {
-  gccaps = nullptr;
+  gccaps = 0;
   gccaps |= ( QPaintEngine::PrimitiveTransform
               // | QPaintEngine::PatternTransform
               | QPaintEngine::PixmapTransform

src/core/qgsvectorlayer.cpp

@@ -199,7 +199,7 @@ QString QgsVectorLayer::storageType() const
   {
     return mDataProvider->storageType();
   }
-  return nullptr;
+  return QString();
 }
 
 
@@ -209,7 +209,7 @@ QString QgsVectorLayer::capabilitiesString() const
   {
     return mDataProvider->capabilitiesString();
   }
-  return nullptr;
+  return QString();
 }
 
 QString QgsVectorLayer::dataComment() const
@@ -992,7 +992,7 @@ QString QgsVectorLayer::subsetString() const
   if ( !mValid || !mDataProvider )
   {
     QgsDebugMsg( "invoked with invalid layer or null mDataProvider" );
-    return nullptr;
+    return QString();
   }
   return mDataProvider->subsetString();
 }

src/gui/editorwidgets/qgsphotowidgetfactory.cpp

@@ -41,8 +41,8 @@ QgsEditorWidgetConfig QgsPhotoWidgetFactory::readConfig( const QDomElement& conf
 
   QgsEditorWidgetConfig cfg;
 
-  cfg.insert( "Height", configElement.attribute( "Height", nullptr ).toInt() );
-  cfg.insert( "Width", configElement.attribute( "Width", nullptr ).toInt() );
+  cfg.insert( "Height", configElement.attribute( "Height", 0 ).toInt() );
+  cfg.insert( "Width", configElement.attribute( "Width", 0 ).toInt() );
 
   return cfg;
 }

src/gui/editorwidgets/qgswebviewwidgetfactory.cpp

@@ -41,8 +41,8 @@ QgsEditorWidgetConfig QgsWebViewWidgetFactory::readConfig( const QDomElement& co
 
   QgsEditorWidgetConfig cfg;
 
-  cfg.insert( "Height", configElement.attribute( "Height", nullptr ).toInt() );
-  cfg.insert( "Width", configElement.attribute( "Width", nullptr ).toInt() );
+  cfg.insert( "Height", configElement.attribute( "Height", 0 ).toInt() );
+  cfg.insert( "Width", configElement.attribute( "Width", 0 ).toInt() );
 
   return cfg;
 }

src/gui/effects/qgseffectstackpropertieswidget.h

@@ -155,7 +155,7 @@ class GUI_EXPORT QgsEffectStackPropertiesDialog: public QgsDialog
      * @param parent parent widget
      * @param f window flags
      */
-    QgsEffectStackPropertiesDialog( QgsEffectStack* stack, QWidget* parent = nullptr, const Qt::WindowFlags& f = nullptr );
+    QgsEffectStackPropertiesDialog( QgsEffectStack* stack, QWidget* parent = nullptr, const Qt::WindowFlags& f = 0 );
     ~QgsEffectStackPropertiesDialog();
 
     /** Returns effect stack attached to the dialog

src/gui/layertree/qgslayertreemapcanvasbridge.cpp

@@ -223,7 +223,7 @@ void QgsLayerTreeMapCanvasBridge::readProject( const QDomDocument& doc )
       itemElem = itemElem.nextSiblingElement( "item" );
     }
 
-    setHasCustomLayerOrder( customOrderElem.attribute( "enabled", nullptr ).toInt() );
+    setHasCustomLayerOrder( customOrderElem.attribute( "enabled", QString() ).toInt() );
     setCustomLayerOrder( order );
   }
 }