Use quitter to shut down tabbed browser

Before this change, we did shut down TabbedBrowser (and thus all the tabs) from
the closeEvent of MainWindow. However, this has (at least) two problems:

1) When starting with --nowindow, we never get a window close event when
shutting down. Since Qt 5.14 (or probably since the new PyQt exit scheme), this
leads to various segfaults around QStyleSheetStyle:

  [...]
  QStyleSheetStyle::event(QEvent*) (this=0x5640dfe08940, e=0x7ffe8b8f5eb0) at styles/qstylesheetstyle.cpp:6040
  [...]
  QCoreApplication::notifyInternal2(QObject*, QEvent*) (receiver=0x5640dfe08940, event=0x7ffe8b8f5eb0) at ../../include/QtCore/../../src/corelib/kernel/qobject.h:153
  QApplicationPrivate::setFocusWidget(QWidget*, Qt::FocusReason) (reason=Qt::OtherFocusReason, focus=<optimized out>) at /usr/include/c++/9.2.0/bits/atomic_base.h:413
  QApplicationPrivate::setFocusWidget(QWidget*, Qt::FocusReason) (focus=focus@entry=0x0, reason=reason@entry=Qt::OtherFocusReason) at kernel/qapplication.cpp:1691
  QWidget::clearFocus() (this=this@entry=0x5640dff74640) at kernel/qwidget.cpp:6514
  QWidget::~QWidget() (this=0x5640dff74640, __in_chrg=<optimized out>) at kernel/qwidget.cpp:1467
  sipQWidget::~sipQWidget() (this=0x5640dff74640, __in_chrg=<optimized out>) at sipQtWidgetsQWidget.cpp:355
  sipQWidget::~sipQWidget() (this=0x5640dff74640, __in_chrg=<optimized out>) at sipQtWidgetsQWidget.cpp:358
  QObjectPrivate::deleteChildren() (this=this@entry=0x5640dfee2ed0) at kernel/qobject.cpp:2123
  QWidget::~QWidget() (this=0x5640dff57f10, __in_chrg=<optimized out>) at kernel/qwidget.cpp:1530
  QStackedWidget::~QStackedWidget() (this=0x5640dff57f10, __in_chrg=<optimized out>) at widgets/qstackedwidget.cpp:145
  QObjectPrivate::deleteChildren() (this=this@entry=0x5640e006f7d0) at kernel/qobject.cpp:2123
  QWidget::~QWidget() (this=0x7fb6a0005b50, __in_chrg=<optimized out>) at kernel/qwidget.cpp:1530
  sipQTabWidget::~sipQTabWidget() (this=0x7fb6a0005b50, __in_chrg=<optimized out>) at sipQtWidgetsQTabWidget.cpp:326
  sipQTabWidget::~sipQTabWidget() (this=0x7fb6a0005b50, __in_chrg=<optimized out>) at sipQtWidgetsQTabWidget.cpp:329
  QObjectPrivate::deleteChildren() (this=this@entry=0x5640df3d3030) at kernel/qobject.cpp:2123
  QWidget::~QWidget() (this=0x5640df86e200, __in_chrg=<optimized out>) at kernel/qwidget.cpp:1530
  sipQWidget::~sipQWidget() (this=0x5640df86e200, __in_chrg=<optimized out>) at sipQtWidgetsQWidget.cpp:355
  sipQWidget::~sipQWidget() (this=0x5640df86e200, __in_chrg=<optimized out>) at sipQtWidgetsQWidget.cpp:358
  cleanup_qobject(sipSimpleWrapper*, void*) (sw=0x7fb694fb38b0, closure=0x5640df761b80) at ../../qpy/QtCore/qpycore_public_api.cpp:66
  sip_api_visit_wrappers (visitor=0x7fb6bdae33ab <cleanup_qobject(sipSimpleWrapper*, void*)>, closure=0x5640df761b80) at siplib.c:13227
  pyqt5_cleanup_qobjects() () at ../../qpy/QtCore/qpycore_public_api.cpp:78
  cleanup_on_exit(PyObject*, PyObject*) () at ../../qpy/QtCore/qpycore_init.cpp:37
  [...]

  [...]
  QObject::inherits(char const*) const (classname=0x7ffff30723cb "QMacStyle", this=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qobject.h:428
  QStyleSheetStyle::getDefaultStyleSheet() const (this=this@entry=0x5555564b8b70) at styles/qstylesheetstyle_default.cpp:157
  QStyleSheetStyle::styleRules(QObject const*) const (this=0x5555564b8b70, obj=<optimized out>) at styles/qstylesheetstyle.cpp:1607
  QStyleSheetStyle::renderRule(QObject const*, int, unsigned long long) const (this=this@entry=0x5555564b8b70, obj=<optimized out>, obj@entry=0x555556637bb0, element=element@entry=0, state=<optimized out>) at styles/qstylesheetstyle.cpp:1803
  QStyleSheetStyle::setGeometry(QWidget*) (this=this@entry=0x5555564b8b70, w=w@entry=0x555556637bb0) at styles/qstylesheetstyle.cpp:2518
  QStyleSheetStyle::unpolish(QWidget*) (w=0x555556637bb0, this=0x5555564b8b70) at styles/qstylesheetstyle.cpp:2948
  QStyleSheetStyle::unpolish(QWidget*) (this=0x5555564b8b70, w=0x555556637bb0) at styles/qstylesheetstyle.cpp:2936
  QWidgetPrivate::setStyle_helper(QStyle*, bool) (this=this@entry=0x5555565ae550, newStyle=newStyle@entry=0x0, propagate=propagate@entry=true) at kernel/qwidget.cpp:2639
  QWidgetPrivate::inheritStyle() (this=this@entry=0x5555565ae550) at kernel/qwidget.cpp:2714
  QWidget::setParent(QWidget*, QFlags<Qt::WindowType>) (this=this@entry=0x555556637bb0, parent=<optimized out>, parent@entry=0x0, f=...) at kernel/qwidget.cpp:10457
  QWidget::setParent(QWidget*) (parent=0x0, this=0x555556637bb0) at ../../include/QtCore/../../src/corelib/global/qflags.h:140
  QWidget::setParent(QWidget*) (this=this@entry=0x555556637bb0, parent=parent@entry=0x0) at kernel/qwidget.cpp:10322
  QtWebEngineCore::RenderWidgetHostViewQtDelegateWidget::removeParentBeforeParentDelete() (this=0x555556637bb0) at /tmp/makepkg/qt5-webengine-debug/src/qtwebengine-everywhere-src-5.14.0/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.cpp:192
  QtPrivate::QSlotObjectBase::call(QObject*, void**) (a=0x7fffffffd570, r=0x555556637bb0, this=0x5555566326a0) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:394
  doActivate<false>(QObject*, int, void**) (sender=0x555556644a00, signal_index=0, argv=0x7fffffffd570) at kernel/qobject.cpp:3870
  QMetaObject::activate(QObject*, QMetaObject const*, int, void**) (sender=sender@entry=0x555556644a00, m=m@entry=0x7ffff62fe320 <QObject::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x7fffffffd570) at kernel/qobject.cpp:3930
  QObject::destroyed(QObject*) (this=this@entry=0x555556644a00, _t1=<optimized out>, _t1@entry=0x555556644a00) at .moc/moc_qobject.cpp:219
  QWidget::~QWidget() (this=0x555556644a00, __in_chrg=<optimized out>) at kernel/qwidget.cpp:1505
  sipQWebEngineView::~sipQWebEngineView() () at /usr/lib/python3.8/site-packages/PyQt5/QtWebEngineWidgets.abi3.so
  QObjectPrivate::deleteChildren() (this=this@entry=0x555556671b40) at kernel/qobject.cpp:2123
  QWidget::~QWidget() (this=0x55555663cd90, __in_chrg=<optimized out>) at kernel/qwidget.cpp:1530
  sipQWidget::~sipQWidget() (this=0x55555663cd90, __in_chrg=<optimized out>) at sipQtWidgetsQWidget.cpp:355
  sipQWidget::~sipQWidget() (this=0x55555663cd90, __in_chrg=<optimized out>) at sipQtWidgetsQWidget.cpp:358
  QObjectPrivate::deleteChildren() (this=this@entry=0x5555565fbab0) at kernel/qobject.cpp:2123
  QWidget::~QWidget() (this=0x5555565bbb80, __in_chrg=<optimized out>) at kernel/qwidget.cpp:1530
  QStackedWidget::~QStackedWidget() (this=0x5555565bbb80, __in_chrg=<optimized out>) at widgets/qstackedwidget.cpp:145
  QObjectPrivate::deleteChildren() (this=this@entry=0x55555669aa80) at kernel/qobject.cpp:2123
  QWidget::~QWidget() (this=0x7fffd8005a90, __in_chrg=<optimized out>) at kernel/qwidget.cpp:1530
  sipQTabWidget::~sipQTabWidget() (this=0x7fffd8005a90, __in_chrg=<optimized out>) at sipQtWidgetsQTabWidget.cpp:326
  sipQTabWidget::~sipQTabWidget() (this=0x7fffd8005a90, __in_chrg=<optimized out>) at sipQtWidgetsQTabWidget.cpp:329
  QObjectPrivate::deleteChildren() (this=this@entry=0x555555b5f8b0) at kernel/qobject.cpp:2123
  QWidget::~QWidget() (this=0x5555565fc9f0, __in_chrg=<optimized out>) at kernel/qwidget.cpp:1530
  sipQWidget::~sipQWidget() (this=0x5555565fc9f0, __in_chrg=<optimized out>) at sipQtWidgetsQWidget.cpp:355
  sipQWidget::~sipQWidget() (this=0x5555565fc9f0, __in_chrg=<optimized out>) at sipQtWidgetsQWidget.cpp:358
  cleanup_qobject(sipSimpleWrapper*, void*) (sw=0x7fffc42bb8b0, closure=0x555555e45d20) at ../../qpy/QtCore/qpycore_public_api.cpp:66
  sip_api_visit_wrappers (visitor=0x7ffff65e83ab <cleanup_qobject(sipSimpleWrapper*, void*)>, closure=0x555555e45d20) at siplib.c:13227
  pyqt5_cleanup_qobjects() () at ../../qpy/QtCore/qpycore_public_api.cpp:78
  cleanup_on_exit(PyObject*, PyObject*) () at ../../qpy/QtCore/qpycore_init.cpp:37
  [...]

2) We sometimes get a "RuntimeError: wrapped C/C++ object of type QCommonStyle
has been deleted" on exit, with this C++ stacktrace:

  pyqt5_err_print() () at ../../qpy/QtCore/qpycore_public_api.cpp:116
  sipVEH_QtCore_PyQt5(_sipSimpleWrapper*, PyGILState_STATE) () at /tmp/makepkg/pyqt5-debug/src/PyQt5-5.14.0/sip/QtCore/qpycore_virtual_error_handler.sip:22
  sip_api_call_error_handler (sipGILState=PyGILState_UNLOCKED, py_self=0x7f1c94711820, error_handler=0x7f1cb9044f4c <sipVEH_QtCore_PyQt5(_sipSimpleWrapper*, PyGILState_STATE)>) at siplib.c:12416
  sip_api_call_procedure_method (gil_state=PyGILState_UNLOCKED, error_handler=0x7f1cb9044f4c <sipVEH_QtCore_PyQt5(_sipSimpleWrapper*, PyGILState_STATE)>, py_self=0x7f1c94711820, method=0x7f1ca116e220, fmt=<optimized out>) at siplib.c:2303
  sipVH_QtWidgets_47(PyGILState_STATE, void (*)(_sipSimpleWrapper*, PyGILState_STATE), _sipSimpleWrapper*, _object*, QWidget*) (sipGILState=PyGILState_UNLOCKED, sipErrorHandler=0x7f1cb9044f4c <sipVEH_QtCore_PyQt5(_sipSimpleWrapper*, PyGILState_STATE)>, sipPySelf=0x7f1c94711820, sipMethod=0x7f1ca116e220, a0=0x55fd39c06df0) at sipQtWidgetscmodule.cpp:6200
  sipQCommonStyle::unpolish(QWidget*) (this=0x55fd39b4bbd0, a0=0x55fd39c06df0) at sipQtWidgetsQCommonStyle.cpp:380
  QStyleSheetStyle::unpolish(QWidget*) (this=0x55fd39baacc0, w=0x55fd39c06df0) at styles/qstylesheetstyle.cpp:2960
  QWidgetPrivate::setStyle_helper(QStyle*, bool) (this=this@entry=0x55fd398b5380, newStyle=newStyle@entry=0x0, propagate=propagate@entry=true) at kernel/qwidget.cpp:2639
  QWidgetPrivate::inheritStyle() (this=this@entry=0x55fd398b5380) at kernel/qwidget.cpp:2714
  QWidget::setParent(QWidget*, QFlags<Qt::WindowType>) (this=this@entry=0x55fd39c06df0, parent=<optimized out>, parent@entry=0x0, f=...) at kernel/qwidget.cpp:10457
  QWidget::setParent(QWidget*) (parent=0x0, this=0x55fd39c06df0) at ../../include/QtCore/../../src/corelib/global/qflags.h:140
  QWidget::setParent(QWidget*) (this=this@entry=0x55fd39c06df0, parent=parent@entry=0x0) at kernel/qwidget.cpp:10322
  QtWebEngineCore::RenderWidgetHostViewQtDelegateWidget::removeParentBeforeParentDelete() (this=0x55fd39c06df0) at /tmp/makepkg/qt5-webengine-debug/src/qtwebengine-everywhere-src-5.14.0/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.cpp:192
  QtPrivate::QSlotObjectBase::call(QObject*, void**) (a=0x7ffff40c2340, r=0x55fd39c06df0, this=0x55fd39c022c0) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:394
  doActivate<false>(QObject*, int, void**) (sender=0x55fd39c1e700, signal_index=0, argv=0x7ffff40c2340) at kernel/qobject.cpp:3870
  QMetaObject::activate(QObject*, QMetaObject const*, int, void**) (sender=sender@entry=0x55fd39c1e700, m=m@entry=0x7f1cb8f22320 <QObject::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x7ffff40c2340) at kernel/qobject.cpp:3930
  QObject::destroyed(QObject*) (this=this@entry=0x55fd39c1e700, _t1=<optimized out>, _t1@entry=0x55fd39c1e700) at .moc/moc_qobject.cpp:219
  QWidget::~QWidget() (this=0x55fd39c1e700, __in_chrg=<optimized out>) at kernel/qwidget.cpp:1505
  sipQWebEngineView::~sipQWebEngineView() () at /usr/lib/python3.8/site-packages/PyQt5/QtWebEngineWidgets.abi3.so
  QObjectPrivate::deleteChildren() (this=this@entry=0x55fd39c1e4a0) at kernel/qobject.cpp:2123
  QWidget::~QWidget() (this=0x55fd39bc1430, __in_chrg=<optimized out>) at kernel/qwidget.cpp:1530
  sipQWidget::~sipQWidget() (this=0x55fd39bc1430, __in_chrg=<optimized out>) at sipQtWidgetsQWidget.cpp:355
  sipQWidget::~sipQWidget() (this=0x55fd39bc1430, __in_chrg=<optimized out>) at sipQtWidgetsQWidget.cpp:358
  QObjectPrivate::deleteChildren() (this=this@entry=0x55fd39b7aa60) at kernel/qobject.cpp:2123
  QWidget::~QWidget() (this=0x55fd39b9e3c0, __in_chrg=<optimized out>) at kernel/qwidget.cpp:1530
  QStackedWidget::~QStackedWidget() (this=0x55fd39b9e3c0, __in_chrg=<optimized out>) at widgets/qstackedwidget.cpp:145
  QObjectPrivate::deleteChildren() (this=this@entry=0x55fd39c68ba0) at kernel/qobject.cpp:2123
  QWidget::~QWidget() (this=0x7f1c98005a70, __in_chrg=<optimized out>) at kernel/qwidget.cpp:1530
  sipQTabWidget::~sipQTabWidget() (this=0x7f1c98005a70, __in_chrg=<optimized out>) at sipQtWidgetsQTabWidget.cpp:326
  sipQTabWidget::~sipQTabWidget() (this=0x7f1c98005a70, __in_chrg=<optimized out>) at sipQtWidgetsQTabWidget.cpp:329
  QObjectPrivate::deleteChildren() (this=this@entry=0x55fd39481760) at kernel/qobject.cpp:2123
  QWidget::~QWidget() (this=0x55fd394c90d0, __in_chrg=<optimized out>) at kernel/qwidget.cpp:1530
  sipQWidget::~sipQWidget() (this=0x55fd394c90d0, __in_chrg=<optimized out>) at sipQtWidgetsQWidget.cpp:355
  sipQWidget::~sipQWidget() (this=0x55fd394c90d0, __in_chrg=<optimized out>) at sipQtWidgetsQWidget.cpp:358
  cleanup_qobject(sipSimpleWrapper*, void*) (sw=0x7f1c946dc940, closure=0x55fd3939f9a0) at ../../qpy/QtCore/qpycore_public_api.cpp:66
  sip_api_visit_wrappers (visitor=0x7f1cb920c3ab <cleanup_qobject(sipSimpleWrapper*, void*)>, closure=0x55fd3939f9a0) at siplib.c:13227
  pyqt5_cleanup_qobjects() () at ../../qpy/QtCore/qpycore_public_api.cpp:78
  cleanup_on_exit(PyObject*, PyObject*) () at ../../qpy/QtCore/qpycore_init.cpp:37
  [...]

Instead, let's use the shutting_down signal we have already to shut down all
the TabbedBrowsers (and their children). I'm not exactly sure why, but this
results in a clean exit.

Fixes #5124
Fixes #5187

1 files changed, 2 insertions, 0 deletions

diff --git a/qutebrowser/mainwindow/tabbedbrowser.py b/qutebrowser/mainwindow/tabbedbrowser.py
index 8c9d1ba9d..f5dc3277b 100644
--- a/qutebrowser/mainwindow/tabbedbrowser.py
+++ b/qutebrowser/mainwindow/tabbedbrowser.py
@@ -35,6 +35,7 @@ from qutebrowser.mainwindow import tabwidget, mainwindow
 from qutebrowser.browser import signalfilter, browsertab, history
 from qutebrowser.utils import (log, usertypes, utils, qtutils, objreg,
                                urlutils, message, jinja)
+from qutebrowser.misc import quitter
 
 
 @attr.s
@@ -235,6 +236,7 @@ class TabbedBrowser(QWidget):
         self.is_private = private
         self.tab_deque = TabDeque()
         config.instance.changed.connect(self._on_config_changed)
+        quitter.instance.shutting_down.connect(self.shutdown)
 
     def _update_stack_size(self):
         newsize = config.instance.get('tabs.undo_stack_size')