Bug 427242

ab43b986f3de20ff15b6438e56bfe29428bee3b1 introduced

> +    d->autoSaveGroup.deleteEntry("RestorePositionForNextInstance");

autoSaveGroup can conceivably be a default constructed group, which is an invalid group without dptr by the looks of it

kconfiggroup.cpp:
> KConfigGroup::KConfigGroup() : d()

This leads to, e.g., konsole crashing just about every time when closing any of the instance's windows because the kconfiggroup is invalid.
Supposedly this should either use a different ctor for the group or guard calls to the group.

(gdb) bt
#0  0x00007f872f34c188 in KConfigGroup::config (this=0x557b35522048) at ./src/core/kconfiggroup.cpp:618
#1  0x00007f872f34f01f in KConfigGroup::deleteEntry (this=this@entry=0x557b35522048, key=key@entry=0x7f872f8bcae0 "RestorePositionForNextInstance", flags=flags@entry=...) at ./src/core/kconfiggroup.cpp:1145
#2  0x00007f872f8649e8 in KMainWindow::closeEvent (this=0x557b35520fd0, e=0x7ffd30aec370) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qflags.h:121
#3  0x00007f872ee21db6 in QWidget::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#4  0x00007f872ef3aa18 in QMainWindow::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5                                                                                                      
#5  0x00007f872f864e6b in KMainWindow::event (this=this@entry=0x557b35520fd0, ev=ev@entry=0x7ffd30aec370) at ./src/kmainwindow.cpp:907
#6  0x00007f872f8afafb in KXmlGuiWindow::event (this=0x557b35520fd0, ev=0x7ffd30aec370) at ./src/kxmlguiwindow.cpp:109
#7  0x00007f872eddecc3 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#8  0x00007f872ede7c70 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#9  0x00007f872ff316aa in QCoreApplication::notifyInternal2 (receiver=0x557b35520fd0, event=0x7ffd30aec370) at ../../include/QtCore/5.15.0/QtCore/private/../../../../../src/corelib/thread/qthread_p.h:325
#10 0x00007f872ee1d17e in QWidgetPrivate::close_helper(QWidgetPrivate::CloseMode) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#11 0x00007f872ff685ae in QtPrivate::QSlotObjectBase::call (a=0x7ffd30aec460, r=0x557b35520fd0, this=0x557b35597140) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:398
#12 doActivate<false> (sender=0x557b3556d390, signal_index=3, argv=0x7ffd30aec460) at kernel/qobject.cpp:3886
#13 0x00007f872ff685ae in QtPrivate::QSlotObjectBase::call (a=0x7ffd30aec5a0, r=0x557b3556d390, this=0x557b35595c70) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:398
#14 doActivate<false> (sender=0x557b355240f0, signal_index=11, argv=0x7ffd30aec5a0) at kernel/qobject.cpp:3886
#15 0x00007f872f961f03 in Konsole::TabbedViewContainer::empty(Konsole::TabbedViewContainer*) () from /usr/lib/x86_64-linux-gnu/libkonsoleprivate.so.20
#16 0x00007f872f9e68aa in Konsole::TabbedViewContainer::viewDestroyed(QObject*) () from /usr/lib/x86_64-linux-gnu/libkonsoleprivate.so.20
#17 0x00007f872ff685ae in QtPrivate::QSlotObjectBase::call (a=0x7ffd30aec6f0, r=0x557b355240f0, this=0x557b3567b140) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:398
#18 doActivate<false> (sender=0x557b3570fd90, signal_index=0, argv=0x7ffd30aec6f0) at kernel/qobject.cpp:3886
#19 0x00007f872ff61977 in QMetaObject::activate (sender=<optimized out>, m=m@entry=0x7f873020fbe0 <QObject::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x7ffd30aec6f0) at kernel/qobject.cpp:3946
#20 0x00007f872ff61a33 in QObject::destroyed (this=<optimized out>, _t1=<optimized out>) at .moc/moc_qobject.cpp:219
#21 0x00007f872ee1d8eb in QWidget::~QWidget() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#22 0x00007f872f967735 in ?? () from /usr/lib/x86_64-linux-gnu/libkonsoleprivate.so.20
#23 0x00007f872ff5eec3 in QObject::event (this=0x557b3570fd90, e=0x557b35679160) at kernel/qobject.cpp:1301
#24 0x00007f872ee21d5d in QWidget::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#25 0x00007f872eed2062 in QFrame::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#26 0x00007f872eddecc3 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#27 0x00007f872ede7c70 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#28 0x00007f872ff316aa in QCoreApplication::notifyInternal2 (receiver=0x557b3570fd90, event=0x557b35679160) at ../../include/QtCore/5.15.0/QtCore/private/../../../../../src/corelib/thread/qthread_p.h:325
#29 0x00007f872ff33fa1 in QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x557b3533d5e0) at kernel/qcoreapplication.cpp:1815
#30 0x00007f872ff8c837 in postEventSourceDispatch (s=0x557b354823e0) at kernel/qeventdispatcher_glib.cpp:277
#31 0x00007f872daf1fbd in g_main_context_dispatch () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#32 0x00007f872daf2240 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#33 0x00007f872daf22e3 in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#34 0x00007f872ff8be92 in QEventDispatcherGlib::processEvents (this=0x557b35488d20, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#35 0x00007f872ff301bb in QEventLoop::exec (this=this@entry=0x7ffd30aecdd0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:141
#36 0x00007f872ff38354 in QCoreApplication::exec () at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#37 0x00007f873030901f in kdemain () from /usr/lib/x86_64-linux-gnu/libkdeinit5_konsole.so
#38 0x00007f872fab60b3 in __libc_start_main (main=0x557b3493b320, argc=6, argv=0x7ffd30aed098, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffd30aed088) at ../csu/libc-start.c:308
#39 0x0000557b3493b35e in _start ()
(gdb) p d
$1 = {d = 0x0}