Qt AppImages broken on Wayland

After upgrading to TAILS 5.8, a couple of Qt based apps I use on TAILS in AppImage form fail to load. Both apps fail with similar error messages.

One of the apps is the latest release of Feather Wallet. Ironically I discovered this bug when attempting to make a donation to TAILS after the release of 5.8 😂

Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on Wayland anyway.
qt.qpa.plugin: Could not find the Qt platform plugin "wayland" in ""
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: xcb, xcb.

I did a number of web searches, came to the conclusion that qtwayland5 is already installed.

Set environment variable QT_QPA_PLATFORM=wayland, it had no effect.

Expected behavior

Apps based on Qt and distributed as AppImage which worked on TAILS pre-5.8 should continue to work on TAILS 5.8+.

Observed behavior

Apps based on Qt and distributed as AppImage which worked on TAILS pre-5.8 do not work on TAILS 5.8.

In 5.8, we forced Qt applications to use Wayland and this broke some features. This workaround makes the application run with XWayland. Using XWayland remove some of the security benefits of Wayland on these applications, for example other X applications can sniff on them like before Wayland.

Related issues

• #19279 (closed)

Workaround

1. Navigate to your AppImage in the Files browser.

2. Do right-click (on Mac, click with two fingers) in the folder and choose Open in Terminal.

3. Execute the following command in the terminal to start your AppImage.

   Replace application.AppImage by the file name of your AppImage.

   unset QT_QPA_PLATFORM ; ./application.AppImage

   For example, to start the Feather wallet version 2.1.2, execute:

   unset QT_QPA_PLATFORM ; ./feather-2.1.2.AppImage