Fix NewFileDialog leaking MainWindow

This also fixes segfaults on quitting when using plugins

src/core/MainWindow.cpp

@@ -472,7 +472,7 @@ void MainWindow::displayWelcomeDialog()
 
 void MainWindow::displayNewFileDialog()
 {
-    NewFileDialog *n = new NewFileDialog();
+    NewFileDialog *n = new NewFileDialog(this);
     newFileDialog = n;
     n->setAttribute(Qt::WA_DeleteOnClose);
     n->show();

src/dialogs/InitialOptionsDialog.cpp

@@ -423,6 +423,5 @@ void InitialOptionsDialog::on_scriptSelectButton_clicked()
 void InitialOptionsDialog::reject()
 {
     done(0);
-    NewFileDialog *n = new NewFileDialog(nullptr);
-    n->show();
+    main->displayNewFileDialog();
 }

src/dialogs/NewFileDialog.cpp

@@ -50,9 +50,10 @@ static QIcon getIconFor(const QString &str, int pos)
     return QIcon(pixmap);
 }
 
-NewFileDialog::NewFileDialog(QWidget *parent) :
-    QDialog(parent),
-    ui(new Ui::NewFileDialog)
+NewFileDialog::NewFileDialog(MainWindow *main) :
+    QDialog(main),
+    ui(new Ui::NewFileDialog),
+    main(main)
 {
     ui->setupUi(this);
     setWindowFlags(windowFlags() & (~Qt::WindowContextHelpButtonHint));
@@ -359,7 +360,6 @@ void NewFileDialog::loadFile(const QString &filename)
     settings.setValue("recentFileList", files);
 
     // Close dialog and open MainWindow/InitialOptionsDialog
-    MainWindow *main = new MainWindow();
     QString ioFile = "";
     if (ui->ioPlugin->currentIndex()) {
         ioFile = ui->ioPlugin->currentText() + "://";

src/dialogs/NewFileDialog.h

@@ -9,12 +9,14 @@ namespace Ui {
 class NewFileDialog;
 }
 
+class MainWindow;
+
 class NewFileDialog : public QDialog
 {
     Q_OBJECT
 
 public:
-    explicit NewFileDialog(QWidget *parent = nullptr);
+    explicit NewFileDialog(MainWindow *main);
     ~NewFileDialog();
 
 private slots:
@@ -46,6 +48,8 @@ protected:
 private:
     std::unique_ptr<Ui::NewFileDialog> ui;
 
+    MainWindow *main;
+
     /**
      * @return true if list is not empty
      */

src/plugins/sample-python/sample_python.py

@@ -6,8 +6,8 @@ from PySide2.QtWidgets import QAction, QVBoxLayout, QLabel, QWidget, QSizePolicy
 
 
 class FortuneWidget(cutter.CutterDockWidget):
-    def __init__(self, main, action):
-        super(FortuneWidget, self).__init__(main, action)
+    def __init__(self, parent, action):
+        super(FortuneWidget, self).__init__(parent, action)
         self.setObjectName("FancyDockWidgetFromCoolPlugin")
         self.setWindowTitle("Sample Python Plugin")
 
@@ -54,10 +54,10 @@ class CutterSamplePlugin(cutter.CutterPlugin):
         pass
 
     def setupInterface(self, main):
-        self.action = QAction("Sample Python Plugin", main)
-        self.action.setCheckable(True)
-        self.widget = FortuneWidget(main, self.action) # we MUST keep a reference to this!
-        main.addPluginDockWidget(self.widget, self.action)
+        action = QAction("Sample Python Plugin", main)
+        action.setCheckable(True)
+        widget = FortuneWidget(main, action)
+        main.addPluginDockWidget(widget, action)
 
 
 # This function will be called by Cutter and should return an instance of the plugin.

src/widgets/CutterDockWidget.cpp

@@ -2,13 +2,13 @@
 #include "core/MainWindow.h"
 
 
-CutterDockWidget::CutterDockWidget(MainWindow *main, QAction *action) :
-    QDockWidget(main),
+CutterDockWidget::CutterDockWidget(MainWindow *parent, QAction *action) :
+    QDockWidget(parent),
     action(action)
 {
     if (action) {
-        main->addToDockWidgetList(this);
-        main->addDockWidgetAction(this, action);
+        parent->addToDockWidgetList(this);
+        parent->addDockWidgetAction(this, action);
         connect(action, &QAction::triggered, this, &CutterDockWidget::toggleDockWidget);
     }
 

src/widgets/CutterDockWidget.h

@@ -12,7 +12,7 @@ class CutterDockWidget : public QDockWidget
     Q_OBJECT
 
 public:
-    explicit CutterDockWidget(MainWindow *main, QAction *action = nullptr);
+    explicit CutterDockWidget(MainWindow *parent, QAction *action = nullptr);
     ~CutterDockWidget() override;
     bool eventFilter(QObject *object, QEvent *event) override;
     bool isVisibleToUser()      { return isVisibleToUserCurrent; }