From be48a0a3536edc2b2c348dd005658f71860b55ce Mon Sep 17 00:00:00 2001
From: Alessandro Pasotti <elpaso@itopen.it>
Date: Sun, 28 Feb 2021 09:50:39 +0100
Subject: [PATCH] Fix DXF export crash

Folloup #41900

Also hides aspatial layers from export candidates. I'm not sure
if this is correct but thre was an assert that was hit
when aspatial layers were present, now I don't know if the
assert (which is about the size of the layers list and
the layer list from custom layer order, that only contains
spatial layers) has been there forever and no one actually
tested in dev mode with aspatial layers.

In any event, getting aspatial layers back into the list
is easy but then we'd need to alter the logic that builds
the ordered layers list and remove the assert.
---
 src/app/qgsdxfexportdialog.cpp | 30 ++++++++++++------------------
 src/app/qgsdxfexportdialog.h   |  1 +
 2 files changed, 13 insertions(+), 18 deletions(-)

diff --git a/src/app/qgsdxfexportdialog.cpp b/src/app/qgsdxfexportdialog.cpp
index ea8c770c9d32..c9a49a295601 100644
--- a/src/app/qgsdxfexportdialog.cpp
+++ b/src/app/qgsdxfexportdialog.cpp
@@ -410,7 +410,7 @@ void QgsVectorLayerAndAttributeModel::selectAll()
   retrieveAllLayers( rootGroup(), allLayers );
   applyVisibility( allLayers, rootGroup() );
 
-  emit dataChanged( QModelIndex(), QModelIndex() );
+  emit dataChanged( index( 0, 0 ), index( rowCount() - 1, 0 ) );
 }
 
 void QgsVectorLayerAndAttributeModel::deSelectAll()
@@ -420,7 +420,7 @@ void QgsVectorLayerAndAttributeModel::deSelectAll()
   QSet<QString> noLayers;
   applyVisibility( noLayers, rootGroup() );
 
-  emit dataChanged( QModelIndex(), QModelIndex() );
+  emit dataChanged( index( 0, 0 ), index( rowCount() - 1, 0 ) );
 }
 
 QgsDxfExportDialog::QgsDxfExportDialog( QWidget *parent, Qt::WindowFlags f )
@@ -441,9 +441,9 @@ QgsDxfExportDialog::QgsDxfExportDialog( QWidget *parent, Qt::WindowFlags f )
   mTreeView->setEditTriggers( QAbstractItemView::AllEditTriggers );
   mTreeView->setItemDelegate( mFieldSelectorDelegate );
 
-  QgsLayerTreeModel *model = new QgsVectorLayerAndAttributeModel( mLayerTreeGroup, this );
-  model->setFlags( QgsLayerTreeModel::Flags() );
-  mTreeView->setModel( model );
+  mModel = new QgsVectorLayerAndAttributeModel( mLayerTreeGroup, this );
+  mModel->setFlags( QgsLayerTreeModel::Flags() );
+  mTreeView->setModel( mModel );
   mTreeView->resizeColumnToContents( 0 );
   mTreeView->header()->show();
 
@@ -507,9 +507,7 @@ QgsDxfExportDialog::~QgsDxfExportDialog()
 void QgsDxfExportDialog::mVisibilityPresets_currentIndexChanged( int index )
 {
   Q_UNUSED( index )
-  QgsVectorLayerAndAttributeModel *model = qobject_cast< QgsVectorLayerAndAttributeModel * >( mTreeView->model() );
-  Q_ASSERT( model );
-  model->applyVisibilityPreset( mVisibilityPresets->currentText() );
+  mModel->applyVisibilityPreset( mVisibilityPresets->currentText() );
 }
 
 void QgsDxfExportDialog::cleanGroup( QgsLayerTreeNode *node )
@@ -522,7 +520,9 @@ void QgsDxfExportDialog::cleanGroup( QgsLayerTreeNode *node )
   const auto constChildren = node->children();
   for ( QgsLayerTreeNode *child : constChildren )
   {
-    if ( QgsLayerTree::isLayer( child ) && QgsLayerTree::toLayer( child )->layer()->type() != QgsMapLayerType::VectorLayer )
+    if ( QgsLayerTree::isLayer( child ) &&
+         ( QgsLayerTree::toLayer( child )->layer()->type() != QgsMapLayerType::VectorLayer ||
+           ! QgsLayerTree::toLayer( child )->layer()->isSpatial() ) )
     {
       toRemove << child;
       continue;
@@ -542,24 +542,18 @@ void QgsDxfExportDialog::cleanGroup( QgsLayerTreeNode *node )
 
 void QgsDxfExportDialog::selectAll()
 {
-  QgsVectorLayerAndAttributeModel *model = qobject_cast< QgsVectorLayerAndAttributeModel *>( mTreeView->model() );
-  Q_ASSERT( model );
-  model->selectAll();
+  mModel->selectAll();
 }
 
 void QgsDxfExportDialog::deSelectAll()
 {
-  QgsVectorLayerAndAttributeModel *model = qobject_cast< QgsVectorLayerAndAttributeModel *>( mTreeView->model() );
-  Q_ASSERT( model );
-  model->deSelectAll();
+  mModel->deSelectAll();
 }
 
 
 QList< QgsDxfExport::DxfLayer > QgsDxfExportDialog::layers() const
 {
-  const QgsVectorLayerAndAttributeModel *model = qobject_cast< const QgsVectorLayerAndAttributeModel *>( mTreeView->model() );
-  Q_ASSERT( model );
-  return model->layers();
+  return mModel->layers();
 }
 
 
diff --git a/src/app/qgsdxfexportdialog.h b/src/app/qgsdxfexportdialog.h
index ca00084eb2c1..f4e48614c889 100644
--- a/src/app/qgsdxfexportdialog.h
+++ b/src/app/qgsdxfexportdialog.h
@@ -108,6 +108,7 @@ class QgsDxfExportDialog : public QDialog, private Ui::QgsDxfExportDialogBase
     void cleanGroup( QgsLayerTreeNode *node );
     QgsLayerTree *mLayerTreeGroup = nullptr;
     FieldSelectorDelegate *mFieldSelectorDelegate = nullptr;
+    QgsVectorLayerAndAttributeModel *mModel = nullptr;
 
     QgsCoordinateReferenceSystem mCRS;
 };