Segmentation fault of itestserver on new connection

[sibskull]

MainWindow::addClient (this=0x5555557891a0) at server.cpp:703
703	    clientConnection->write(current_db_test.at(0));
(gdb) bt
#0  MainWindow::addClient (this=0x5555557891a0) at server.cpp:703
#1  0x00007ffff6d0a9f4 in doActivate<false> (sender=0x555555cb7290, signal_index=3, argv=0x7fffffffdec0, argv@entry=0x0) at kernel/qobject.cpp:3898
#2  0x00007ffff6d03d60 in QMetaObject::activate (sender=sender@entry=0x555555cb7290, m=m@entry=0x7ffff713e280 <QTcpServer::staticMetaObject>, 
    local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3946
#3  0x00007ffff709c490 in QTcpServer::newConnection (this=this@entry=0x555555cb7290) at .moc/moc_qtcpserver.cpp:155
#4  0x00007ffff709d8fb in QTcpServerPrivate::readNotification (this=0x555555cb7610) at socket/qtcpserver.cpp:224
#5  0x00007ffff70ab291 in QReadNotifier::event (this=<optimized out>, e=<optimized out>) at socket/qnativesocketengine.cpp:1274
#6  0x00007ffff79d44ef in QApplicationPrivate::notify_helper (this=<optimized out>, receiver=0x7fffec006d50, e=0x7fffffffe010)
    at kernel/qapplication.cpp:3632
#7  0x00007ffff6cd441a in QCoreApplication::notifyInternal2 (receiver=0x7fffec006d50, event=0x7fffffffe010) at kernel/qcoreapplication.cpp:1063
#8  0x00007ffff6d2c4e5 in socketNotifierSourceDispatch (source=0x555555755530) at kernel/qeventdispatcher_glib.cpp:107
#9  0x00007ffff56e268b in g_main_dispatch (context=0x7fffec005000) at ../glib/gmain.c:3337
#10 g_main_context_dispatch (context=0x7fffec005000) at ../glib/gmain.c:4055
#11 0x00007ffff56e2938 in g_main_context_iterate (context=context@entry=0x7fffec005000, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>)
    at ../glib/gmain.c:4131
#12 0x00007ffff56e29ef in g_main_context_iteration (context=0x7fffec005000, may_block=may_block@entry=1) at ../glib/gmain.c:4196
#13 0x00007ffff6d2b920 in QEventDispatcherGlib::processEvents (this=0x55555571a2a0, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#14 0x00007ffff6cd2e5b in QEventLoop::exec (this=this@entry=0x7fffffffe220, flags=..., flags@entry=...)
    at ../../include/QtCore/../../src/corelib/global/qflags.h:69
#15 0x00007ffff6cdb050 in QCoreApplication::exec () at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#16 0x000055555557b00f in main (argc=<optimized out>, argv=<optimized out>) at main.cpp:53```