OSCAR hangs on Fedora when importing Wellue O2 data

[desaturator]

Hi folks

I'm running OSCAR 1.3.0, built from source, on Ubuntu 20 and it works just fine. On Fedora 35, however, everything seems to work apart from importing Wellue o2 saturation data. I'm following the same procedure (copy from Android phone onto a local file and import the file) as I do on the Ubuntu machine, where everything is fine. On Fedora, though, as soon as I select the file to import, the file selection dialog bix disappears, and OSCAR hangs. It is completely unresponsive to all keyboard and mouse input.

I've attached a thread dump from gdb. It looks to me as if QXdgDesktopPortalFileDialog is still running, but its window has been closed.

I don't know if this is even a problem in OSCAR -- for all I know the problem might by in the Fedora build of Qt5.

This isn't a show-stopper, because I have a computer that works. I just thought you ought to know.

BW, DS

[sawinglogz]

Weird, thank you for the stack trace. Can you copy/paste the contents of Help > Troubleshooting > System Information? It could be a Qt bug.

[desaturator]

Thanks.

===============================================
OSCAR 1.3.0 (linux x86_64)
Built with Qt 5.15.2 on Jan 8 2022 08:10:09

Operating system: Fedora Linux 35 (Workstation Edition)
Graphics Engine: 4.6 (Compatibility Profile) Mesa 21.3.2
Graphics Engine type: OpenGL
=================================================

If there's a way to run OSCAR with additional logging or anything like that, I'm happy to try.

Best wishes, DS

[sawinglogz]

You can generate a zip of the detailed logs (including from previous launches) via Help > Troubleshooting > Create zip of OSCAR diagnostic logs. Then upload that zip to:

https://www.dropbox.com/request/REp6AH7LCGyeOcXfOokH

Please include your forum name (real name not necessary) so that we know who it's from.

Edit: It looks like it may be this bug: https://bugreports.qt.io/browse/QTBUG-90616 -- we create and destroy QGuiApplication at launch to check whether shift is held down. I don't think we can use QCoreApplication to get around it like that bug suggests, but maybe we could make that a Windows-only check. I'll discuss with the other developers.

[desaturator]

I'm sorry, but the "Create ZIP..." function also fails, and in exactly the same way. So perhaps the problem is in anything that uses the file selection dialog box? I'm happy to zip up whatever logs you need manually, if you tell me where they are. There is a logs/ directory in my main OSCAR data directory, full of files with names like "debug.1.txt". Is that it? There's very little in any of those files -- only repeated copies of this:

10407: Warning: Wayland does not support QWindow::requestActivate()

I have no clue what this means, but I get it from other software as well.

[pholynyk]

Warning: Wayland does not support QWindow::requestActivate()

Thank you, that's the clue we need. Next clue will be which OS an version do you use?

which version of QT are you using?

Wayland is a new display manager, and does not use the same interface as the old standard Xorg display manager. Either Wayland or QT must be modified to make them wotk together, and that's beyond our paygrade. We will investigate alternatives.

[desaturator]

Hi

Changing my desktop to use Xorg instead of Wayland did not fix the problem.

What _did_ fix it (aha!) was to ensure that this line gets compiled:

w.setOption(QFileDialog:ontUseNativeDialog, true);

around line 2924 in mainwindow.cpp.

It's already compiled in for Windows, it seems. Looks like it needs to be called for Fedora as well.

FWIW I note that with the normal configuration, the file dialog box is not properly anchored to the parent window, and sometimes appears behind it. The program hangs whether I select a file or not -- it will hang if I hit Escape, for example.

I think this is a bug either in Qt or Gnome. For my part, I would be perfectly happy to see the Qt open file dialog rather than the Gnome one (which sucks) -- and now I can

For the record:

$ uname -a
Linux fedora 5.14.10-300.fc35.x86_64 #1 SMP Thu Oct 7 20:48:44 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

$ cat /etc/fedora-release
Fedora release 35 (Thirty Five)

$ rpm -q -a |grep qt5-qtbase
qt5-qtbase-5.15.2-30.fc35.x86_64

Shall I log a bug for this in GitLab (or wherever you record bugs) ? It might be worth reporting this behaviour, so other folks can see the workaround.

BW, DS

[pholynyk]

Yes, please log it in our gitlab Issues list. It may be that the best solution is to always set DontUse... to true. We'll have see what it looks like on Macs and other Linuxes that Fedora.

[desaturator]

Done.

https://gitlab.com/pholy/OSCAR-code/-/issues/49

Incidentally, my Ubuntu system, which has Qt 5.12.8 and Gnome 3.36.8 does not have the problem.

[pholynyk]

Thanks for documenting that for us, so it can't be forgotten.

My Debian 11 (Bullseye) system has QT 5.15.2 and Gnome 3.38 and does not have the problem.