Bug 435514

SUMMARY
After this upstream commit (which is not in 5.15.2, but is in the KDE maintenance branch and, presumably, in the commercial 5.15.3), kbibtex crashes immediately at startup

https://code.qt.io/cgit/qt/qtbase.git/commit/?h=5.15&id=4796296ed6d7b05e2ba94e5a8a28c48350a3c492

Backtrace:

(gdb) bt
#0  0x00007ffff77bf75c in FileModel::element(int) const (this=0x0, row=0) at /usr/src/debug/kbibtex-0.9.2/src/data/models/filemodel.cpp:399
#1  0x00007ffff7f14f78 in SortFilterFileModel::filterAcceptsRow(int, QModelIndex const&) const
    (this=0x55555803cbe0, source_row=<optimized out>, source_parent=<optimized out>)
    at /usr/src/debug/kbibtex-0.9.2/src/gui/file/sortfilterfilemodel.cpp:151
#2  0x00007ffff62d95f7 in QSortFilterProxyModelPrivate::filterAcceptsRowInternal(int, QModelIndex const&) const
    (this=this@entry=0x555557eae3c0, source_row=<optimized out>, source_parent=...) at itemmodels/qsortfilterproxymodel.cpp:446
#3  0x00007ffff62dd4aa in QSortFilterProxyModelPrivate::create_mapping(QModelIndex const&) const (this=this@entry=0x555557eae3c0, source_parent=...)
    at itemmodels/qsortfilterproxymodel.cpp:504
#4  0x00007ffff62e4a0c in QSortFilterProxyModel::setSourceModel(QAbstractItemModel*) (this=0x55555803cbe0, sourceModel=0x7fffffffd700)
    at itemmodels/qsortfilterproxymodel.cpp:2149
#5  0x00007ffff7f16012 in SortFilterFileModel::setSourceModel(QAbstractItemModel*) (this=this@entry=0x55555803cbe0, model=0x555557eaf190)
    at /usr/src/debug/kbibtex-0.9.2/src/gui/file/sortfilterfilemodel.cpp:43
#6  0x00007fffc4015543 in KBibTeXPart::KBibTeXPartPrivate::openFile(QUrl const&, QString const&) (this=this@entry=
    0x555557dd8310, url=..., localFilePath=...) at /usr/src/debug/kbibtex-0.9.2/src/parts/part.cpp:391
#7  0x00007fffc400e1e2 in KBibTeXPart::openFile() (this=0x555557e4d430) at /usr/src/debug/kbibtex-0.9.2/src/parts/part.cpp:964
#8  0x00007ffff7c4a315 in  () at /usr/lib/libKF5Parts.so.5
#9  0x00007ffff7c4b0e4 in KParts::ReadOnlyPart::openUrl(QUrl const&) () at /usr/lib/libKF5Parts.so.5
#10 0x000055555559cb54 in OpenFileInfo::OpenFileInfoPrivate::createPart(QWidget*, QExplicitlySharedDataPointer<KService>)
    (this=0x555555b839c0, newWidgetParent=0x555555a791a0, newServicePtr=...) at /usr/src/debug/kbibtex-0.9.2/src/program/openfileinfo.cpp:139
#11 0x000055555559bd67 in OpenFileInfo::part(QWidget*, QExplicitlySharedDataPointer<KService>)
    (this=this@entry=0x555555b844c0, parent=parent@entry=0x555555a791a0, servicePtr=...) at /usr/src/debug/kbibtex-0.9.2/src/program/openfileinfo.cpp:263
#12 0x00005555555809cf in MDIWidget::setFile(OpenFileInfo*, QExplicitlySharedDataPointer<KService>)
    (this=0x555555a791a0, openFileInfo=0x555555b844c0, servicePtr=...) at /usr/src/debug/kbibtex-0.9.2/src/program/mdiwidget.cpp:242
#13 0x000055555557c766 in QtPrivate::FunctorCall<QtPrivate::IndexesList<0, 1>, QtPrivate::List<OpenFileInfo*, QExplicitlySharedDataPointer<KService> >, void, void (MDIWidget::*)(OpenFileInfo*, QExplicitlySharedDataPointer<KService>)>::call(void (MDIWidget::*)(OpenFileInfo*, QExplicitlySharedDataPointer<KSer--Type <RET> for more, q to quit, c to continue without paging--
vice>), MDIWidget*, void**) (arg=<optimized out>, o=<optimized out>, f=<optimized out>) at /usr/include/qt/QtCore/qobjectdefs_impl.h:152
#14 QtPrivate::FunctionPointer<void (MDIWidget::*)(OpenFileInfo*, QExplicitlySharedDataPointer<KService>)>::call<QtPrivate::List<OpenFileInfo*, QExplicitlySharedDataPointer<KService> >, void>(void (MDIWidget::*)(OpenFileInfo*, QExplicitlySharedDataPointer<KService>), MDIWidget*, void**)
    (arg=<optimized out>, o=<optimized out>, f=<optimized out>) at /usr/include/qt/QtCore/qobjectdefs_impl.h:185
#15 QtPrivate::QSlotObject<void (MDIWidget::*)(OpenFileInfo*, QExplicitlySharedDataPointer<KService>), QtPrivate::List<OpenFileInfo*, QExplicitlySharedDataPointer<KService> >, void>::impl(int, QtPrivate::QSlotObjectBase*, QObject*, void**, bool*)
    (which=<optimized out>, this_=<optimized out>, r=<optimized out>, a=<optimized out>, ret=<optimized out>)
    at /usr/include/qt/QtCore/qobjectdefs_impl.h:418
#16 0x00007ffff6349a0c in QtPrivate::QSlotObjectBase::call(QObject*, void**) (a=0x7fffffffdc50, r=0x555555a791a0, this=0x555557ddc120)
    at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:398
#17 doActivate<false>(QObject*, int, void**) (sender=0x555555c3cdb0, signal_index=3, argv=0x7fffffffdc50) at kernel/qobject.cpp:3886
#18 0x00007ffff6340df5 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**)
    (sender=sender@entry=0x555555c3cdb0, m=m@entry=0x5555555b9aa0 <OpenFileInfoManager::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x7fffffffdc50) at kernel/qobject.cpp:3946
#19 0x0000555555574cd5 in OpenFileInfoManager::currentChanged(OpenFileInfo*, QExplicitlySharedDataPointer<KService>)
    (this=this@entry=0x555555c3cdb0, _t1=<optimized out>, _t1@entry=0x555555b844c0, _t2=...)
    at /usr/src/debug/build/src/program/kbibtex_autogen/EWIEGA46WW/moc_openfileinfo.cpp:280
#20 0x0000555555599d61 in OpenFileInfoManager::setCurrentFile(OpenFileInfo*, QExplicitlySharedDataPointer<KService>)
    (this=0x555555c3cdb0, openFileInfo=openFileInfo@entry=0x555555b844c0, servicePtr=...)
    at /usr/src/debug/kbibtex-0.9.2/src/program/openfileinfo.cpp:714
#21 0x000055555559a04e in operator() (__closure=0x7fffffffdcf0) at /usr/include/qt/QtCore/qshareddata.h:183
#22 QtPrivate::FunctorCall<QtPrivate::IndexesList<>, QtPrivate::List<>, void, OpenFileInfoManager::OpenFileInfoManager(QObject*)::<lambda()> >::call
    (arg=<optimized out>, f=...) at /usr/include/qt/QtCore/qobjectdefs_impl.h:146
#23 QtPrivate::Functor<OpenFileInfoManager::OpenFileInfoManager(QObject*)::<lambda()>, 0>::call<QtPrivate::List<>, void> (arg=<optimized out>, f=...)
    at /usr/include/qt/QtCore/qobjectdefs_impl.h:256
--Type <RET> for more, q to quit, c to continue without paging--
#24 QtPrivate::QFunctorSlotObject<OpenFileInfoManager::OpenFileInfoManager(QObject*)::<lambda()>, 0, QtPrivate::List<>, void>::impl(int, QtPrivate::QSlotObjectBase *, QObject *, void **, bool *) (which=<optimized out>, this_=0x7fffffffdce0, r=<optimized out>, a=<optimized out>, ret=<optimized out>)
    at /usr/include/qt/QtCore/qobjectdefs_impl.h:443
#25 0x00007ffff634f9c3 in QtPrivate::QSlotObjectBase::call(QObject*, void**) (a=0x7fffffffdd30, r=<optimized out>, this=<optimized out>)
    at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:398
#26 QSingleShotTimer::timerEvent(QTimerEvent*) (this=0x555555a803d0) at kernel/qtimer.cpp:320
#27 0x00007ffff634185d in QObject::event(QEvent*) (this=0x555555a803d0, e=0x7fffffffe080) at kernel/qobject.cpp:1291
#28 0x00007ffff6dc9c26 in QApplicationPrivate::notify_helper(QObject*, QEvent*) (this=this@entry=
    0x5555555bf000, receiver=receiver@entry=0x555555a803d0, e=e@entry=0x7fffffffe080) at kernel/qapplication.cpp:3632
#29 0x00007ffff6dd24ee in QApplication::notify(QObject*, QEvent*) (this=0x7fffffffe3d0, receiver=0x555555a803d0, e=0x7fffffffe080)
    at kernel/qapplication.cpp:2972
#30 0x00007ffff6307338 in QCoreApplication::notifyInternal2(QObject*, QEvent*) (receiver=0x555555a803d0, event=0x7fffffffe080)
    at kernel/qcoreapplication.cpp:1064
#31 0x00007ffff630754c in QCoreApplication::sendEvent(QObject*, QEvent*) (receiver=<optimized out>, event=<optimized out>)
    at kernel/qcoreapplication.cpp:1462
#32 0x00007ffff63709d3 in QTimerInfoList::activateTimers() (this=0x55555561df50) at kernel/qtimerinfo_unix.cpp:643
#33 0x00007ffff637121a in timerSourceDispatch(GSource*, GSourceFunc, gpointer) (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:183
#34 0x00007fffea3b4f9c in g_main_context_dispatch () at /usr/lib/libglib-2.0.so.0
#35 0x00007fffea408a49 in  () at /usr/lib/libglib-2.0.so.0
#36 0x00007fffea3b26f1 in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#37 0x00007ffff63715b4 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x5555556ff670, flags=...)
    at kernel/qeventdispatcher_glib.cpp:423
#38 0x00007fffe2d61e06 in QXcbGlibEventDispatcher::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=<optimized out>, flags=...)
    at qxcbeventdispatcher.cpp:143
#39 0x00007ffff6304df1 in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7fffffffe2e0, flags=..., flags@entry=...)
--Type <RET> for more, q to quit, c to continue without paging--
    at kernel/qeventloop.cpp:139
#40 0x00007ffff6305435 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7fffffffe2e0, flags=flags@entry=...)
    at ../../include/QtCore/../../src/corelib/global/qflags.h:69
#41 0x00007ffff630fa2e in QCoreApplication::exec() () at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#42 0x00007ffff66dabbe in QGuiApplication::exec() () at kernel/qguiapplication.cpp:1867
#43 0x00007ffff6dc9b9b in QApplication::exec() () at kernel/qapplication.cpp:2824
#44 0x00005555555734a3 in main(int, char**) (argc=<optimized out>, argv=<optimized out>) at /usr/src/debug/kbibtex-0.9.2/src/program/program.cpp:124