[addlayerbutton] Prevent a crash when the layer list is rebuilt after a change in the layer tree

elpaso · elpaso · commit 01b4eebceaa0 · 2017-06-02T16:57:45.000+02:00
diff --git a/src/providers/virtual/qgsvirtuallayersourceselect.cpp b/src/providers/virtual/qgsvirtuallayersourceselect.cpp
@@ -82,12 +82,14 @@ QgsVirtualLayerSourceSelect::QgsVirtualLayerSourceSelect( QWidget *parent, Qt::W
   connect( mLayerNameCombo, static_cast<void ( QComboBox::* )( int )>( &QComboBox::currentIndexChanged ), this, &QgsVirtualLayerSourceSelect::onLayerComboChanged );
   onLayerComboChanged( mLayerNameCombo->currentIndex() );
 
-  // prepare embedded layer selection dialog and
+  // Prepare embedded layer selection dialog and
   // connect to model changes in the treeview
   if ( mTreeView )
   {
     mEmbeddedSelectionDialog = new QgsEmbeddedLayerSelectDialog( this, mTreeView );
-    connect( mTreeView->model(), &QAbstractItemModel::rowsInserted, this, &QgsVirtualLayerSourceSelect::updateLayersList );
+    // Queued connection here prevents the updateLayerList to run before the tree layer
+    // pointer points to the effective layer.
+    connect( mTreeView->model(), &QAbstractItemModel::rowsInserted, this, &QgsVirtualLayerSourceSelect::updateLayersList, Qt::QueuedConnection );
     connect( mTreeView->model(), &QAbstractItemModel::rowsRemoved, this, &QgsVirtualLayerSourceSelect::updateLayersList );
     connect( mTreeView->model(), &QAbstractItemModel::dataChanged, this, &QgsVirtualLayerSourceSelect::updateLayersList );
   }
@@ -247,6 +249,7 @@ void QgsVirtualLayerSourceSelect::updateLayersList()
     QgsLayerTreeModel *model = qobject_cast<QgsLayerTreeModel *>( mTreeView->model() );
     Q_FOREACH ( QgsLayerTreeLayer *layer, model->rootGroup()->findLayers() )
     {
+      Q_ASSERT( layer->layer() );
       if ( layer->layer()->type() == QgsMapLayer::VectorLayer && static_cast<QgsVectorLayer *>( layer->layer() )->providerType() == QLatin1String( "virtual" ) )
       {
         // store layer's id as user data

Original file line number	Diff line number	Diff line change
`@@ -82,12 +82,14 @@ QgsVirtualLayerSourceSelect::QgsVirtualLayerSourceSelect( QWidget *parent, Qt::W`
`82`	`82`	`connect( mLayerNameCombo, static_cast<void ( QComboBox::* )( int )>( &QComboBox::currentIndexChanged ), this, &QgsVirtualLayerSourceSelect::onLayerComboChanged );`
`83`	`83`	`onLayerComboChanged( mLayerNameCombo->currentIndex() );`
`84`	`84`
`85`		`- // prepare embedded layer selection dialog and`
	`85`	`+ // Prepare embedded layer selection dialog and`
`86`	`86`	`// connect to model changes in the treeview`
`87`	`87`	`if ( mTreeView )`
`88`	`88`	`{`
`89`	`89`	`mEmbeddedSelectionDialog = new QgsEmbeddedLayerSelectDialog( this, mTreeView );`
`90`		`- connect( mTreeView->model(), &QAbstractItemModel::rowsInserted, this, &QgsVirtualLayerSourceSelect::updateLayersList );`
	`90`	`+ // Queued connection here prevents the updateLayerList to run before the tree layer`
	`91`	`+ // pointer points to the effective layer.`
	`92`	`+ connect( mTreeView->model(), &QAbstractItemModel::rowsInserted, this, &QgsVirtualLayerSourceSelect::updateLayersList, Qt::QueuedConnection );`
`91`	`93`	`connect( mTreeView->model(), &QAbstractItemModel::rowsRemoved, this, &QgsVirtualLayerSourceSelect::updateLayersList );`
`92`	`94`	`connect( mTreeView->model(), &QAbstractItemModel::dataChanged, this, &QgsVirtualLayerSourceSelect::updateLayersList );`
`93`	`95`	`}`
`@@ -247,6 +249,7 @@ void QgsVirtualLayerSourceSelect::updateLayersList()`
`247`	`249`	`QgsLayerTreeModel model = qobject_cast<QgsLayerTreeModel >( mTreeView->model() );`
`248`	`250`	`Q_FOREACH ( QgsLayerTreeLayer *layer, model->rootGroup()->findLayers() )`
`249`	`251`	`{`
	`252`	`+ Q_ASSERT( layer->layer() );`
`250`	`253`	`if ( layer->layer()->type() == QgsMapLayer::VectorLayer && static_cast<QgsVectorLayer *>( layer->layer() )->providerType() == QLatin1String( "virtual" ) )`
`251`	`254`	`{`
`252`	`255`	`// store layer's id as user data`