QComboBox selection makes computer crash

IgorRecioH

@JonB said in QComboBox selection makes computer crash:

@IgorRecioH
Is the only combobox stuff you do the on_filterByCbx_currentIndexChanged()? What you are describing seems unexpected and not connected to anything in your application. Is that is what is being triggered when it crashes? Does a standalone combobox exhibit this problem? Else edit up/down from there.

That combobox you mention is the only one which has currentIndexChanged signal. The value of the rest of comboboxes are read when clicking a button. Anyway, all of them exhibit this problem, yes.

Quite crazy, must say. When I try one of the examples provided in QtDesigner, they work fine. It is true that this example do not have a .ui file, I mean, they create the objects directly in C++ code.

IgorRecioH

Just as update: I have compiled my Qt app in a Windows10 VM and I cannot reproduce the problem and it's working fine. So maybe it is related to Ubuntu.

Furthermore, exploring /var/log/syslog I found this line when crashing the app:

Feb  9 21:17:27 igorrecio-XXX gnome-shell[53810]: GNOME Shell crashed with signal 11
Feb  9 21:17:27 igorrecio-XXX gnome-shell[53810]: == Stack trace for context 0x56459ff96490 ==

Searching on the internet, seems to be something related to GNOME, specifically in Ubuntu 22.04...

JonB

@IgorRecioH
Since there was nothing in your code changing combobox behaviour it does sound right that any combobox will do it and it is some issue on your platform. But I (and others) use Ubuntu 22.04 with GNOME and have no trouble, though I am Qt5. It would be very serious if what you report happens to everyone, you are saying 22.04/GNOME/Qt6 cannot work with a combobox, I would have expected to hear about this! Maybe try a Qt other than 6.4.2?

SamuelAdesola

I am experiencing same problem now

? Offline

I have also same problem using Qt6 6.4.2. I am waiting for a solution. I don't want to migrate Qt5 because of this problem.

JoeCFD

@Dogukan-Arat I tested the /widgets/painting/basicdrawing example which has a few combo boxes and do not see any crash.
Qt 6.5.0 and LUbuntu 22.04

JonB

@JoeCFD
I seem to remember some recent post on something "similar" to this may have stated that Lubuntu worked but Ubuntu did not?

JoeCFD

@JonB I will check it out later.

JoeCFD

@JoeCFD Tried the same example on Qt 6.4.0 and Ubuntu 22.04. No crash.

iPriyonto

I am having the same problem too. However, in my case, it crashes only when I have the combo box open, and I try to interact with other widgets I have on the window.

Mriv31

Same problem.

Ubuntu 22.04 LTS - Wayland
PyQt6 6.5.0

Li Kui

同样的问题，VMware，Ubuntu-22.04.2，Qt6.5

BosGemiler

I have same issue. When I clicked on combobox, I can see dropdown menu, and everything is fine so far. But when I click on any item in dropdown menu, there appears a crash and I find myself on log in page of ubuntu.

It's not the only bug I faced in ubuntu. There are many others too. Unfortunately, I didn't see any good release of Ubuntu except Ubuntu 14 and 18.

Goodbye Ubuntu, Welcome Debian !

JoeCFD

@BosGemiler It could be a wayland related issue. Switch to Xorg and try it again.
On Login screen, there is a setting icon and click it to switch to Xorg. The default on Ubuntu now is Wayland.

default

I faced the same issue while working with PyQt6 on Ubuntu 22.04

So I ran the following minimal example:-

from PyQt6.QtWidgets import (
  QApplication,
  QWidget,
  QComboBox,
)

import sys


class Window(QWidget):
  def __init__(self):
    super().__init__()

    combobox = QComboBox(self)
    combobox.addItems(['option 1', 'option 2', 'option 3'])

    self.setGeometry(0,0,500,500)
    self.setWindowTitle('Combobox Bug')
    self.show()


if __name__ == '__main__':
  app = QApplication([])
  window = Window()
  sys.exit(app.exec())

Wayland : It crashes and I am sent to login screen where I have to login again.
Xorg: No crash

Same thing happens on PySide6.

JoeCFD

@default run
strace yourapp
to check if any plugin is missing. You may be able to get some hints about the reasons.

Moritz Ulmer

For a fix, see my comment: https://forum.qt.io/post/762082

The cause is a bug in mutter <= 42.5 under Wayland. Upgrade to proposed to get 42.9 which resolves the issue.