Tell the bridge to update when a bad layer was fixed

This fixes an unreported issue: when a bad layer is fixed
it does not appear in the layer order panel.

The reason why it does not appear is that a bad layer
has no geometry information, and the layer order
model does not list geometryless layers.

But after a bad layer has been fixed, it has a geometry
and the panel should show it.

cherry-pick b45ab5d

Author: elpaso

src/app/qgisapp.cpp

@@ -6934,6 +6934,83 @@ void QgisApp::refreshFeatureActions()
   updateDefaultFeatureAction( mFeatureActionMenu->activeAction() );
 }
 
+void QgisApp::changeDataSource( QgsMapLayer *layer )
+{
+  // Get provider type
+  QString providerType( layer->providerType() );
+  QgsMapLayer::LayerType layerType( layer->type() );
+
+  QgsDataSourceSelectDialog dlg( mBrowserModel, true, layerType );
+
+  if ( dlg.exec() == QDialog::Accepted )
+  {
+    QgsMimeDataUtils::Uri uri( dlg.uri() );
+    if ( uri.isValid() )
+    {
+      bool layerWasValid( layer->isValid() );
+      // Store subset string form vlayer if we are fixing a bad layer
+      QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( layer );
+      QString subsetString;
+      // Get the subset string directly from the data provider because
+      // layer's method will return a null string from invalid layers
+      if ( !layerWasValid && vlayer && vlayer->dataProvider() &&
+           vlayer->dataProvider()->supportsSubsetString() &&
+           !vlayer->dataProvider()->subsetString( ).isEmpty() )
+      {
+        subsetString = vlayer->dataProvider()->subsetString();
+      }
+      layer->setDataSource( uri.uri, layer->name(), uri.providerKey, QgsDataProvider::ProviderOptions() );
+      // Re-apply original style and subset string  when fixing bad layers
+      if ( !( layerWasValid || layer->originalXmlProperties().isEmpty() ) )
+      {
+        if ( ! subsetString.isEmpty() )
+        {
+          vlayer->setSubsetString( subsetString );
+        }
+        QgsReadWriteContext context;
+        context.setPathResolver( QgsProject::instance()->pathResolver() );
+        context.setProjectTranslator( QgsProject::instance() );
+        QString errorMsg;
+        QDomDocument doc;
+        if ( doc.setContent( layer->originalXmlProperties() ) )
+        {
+          QDomNode layer_node( doc.firstChild( ) );
+          if ( ! layer->readSymbology( layer_node, errorMsg, context ) )
+          {
+            QgsDebugMsg( QStringLiteral( "Failed to restore original layer style from stored XML for layer %1: %2" )
+                         .arg( layer->name( ) )
+                         .arg( errorMsg ) );
+          }
+        }
+        else
+        {
+          QgsDebugMsg( QStringLiteral( "Failed to create XML QDomDocument for layer %1: %2" )
+                       .arg( layer->name( ) )
+                       .arg( errorMsg ) );
+        }
+      }
+
+      // All the following code is necessary to refresh the layer
+      QgsLayerTreeModel *model = qobject_cast<QgsLayerTreeModel *>( mLayerTreeView->model() );
+      if ( model )
+      {
+        QgsLayerTreeLayer *tl( model->rootGroup()->findLayer( layer->id() ) );
+        if ( tl && tl->itemVisibilityChecked() )
+        {
+          tl->setItemVisibilityChecked( false );
+          tl->setItemVisibilityChecked( true );
+        }
+      }
+
+      // Tell the bridge that we have fixed a layer
+      if ( ! layerWasValid && layer->isValid() )
+      {
+        QgsProject::instance()->layerTreeRoot()->customLayerOrderChanged( );
+      }
+    }
+  }
+}
+
 void QgisApp::measure()
 {
   mMapCanvas->setMapTool( mMapTools.mMeasureDist );