Distributing a Qt app in a flatpak with WebEngine

I am attempting to package my Qt app as a flatpak.
It relies heavily on QtWebEngine, so I used this as a base app: GitHub - flathub/io.qt.qtwebengine.BaseApp

I am using qt6 with org.kde.Sdk and org.kde.Platform.
It packages successfully but then I get this error immediately when the app opens: module “QtWebEngine” plugin “qtwebenginequickplugin” not found.

The line in question is simply “import QtWebEngine” (QML).
The reason I am posting this here is because when the app is run on the host system (without flatpak) it works completely fine.

Hey, while I haven’t experienced this problem, it’s usually easier, if you can share your manifest etc. if that’s possible for your application.

Here is the manifest:

app-id: ca.stevestudios.Swirl
runtime: org.kde.Platform
runtime-version: ‘6.5’
sdk: org.kde.Sdk
base: io.qt.qtwebengine.BaseApp
base-version: ‘6.5’
command: swirl

  • –share=ipc
  • –socket=x11
  • –socket=wayland
  • –filesystem=host
  • –device=dri
  • –env=QTWEBENGINEPROCESS_PATH=/app/bin/QtWebEngineProcess
  • /app/cleanup-BaseApp.sh
  • name: swirl
    buildsystem: simple
    • install -D ca.stevestudios.Swirl.appdata.xml /app/share/metainfo/ca.stevestudios.Swirl.appdata.xml
    • install -D ca.stevestudios.Swirl.desktop /app/share/applications/ca.stevestudios.Swirl.desktop
    • install -D ca.stevestudios.Swirl.svg /app/share/icons/hicolor/scalable/apps/ca.stevestudios.Swirl.svg
    • install -D ca.stevestudios.Swirl-symbolic.svg /app/share/icons/hicolor/symbolic/apps/ca.stevestudios.Swirl-symbolic.svg
    • type: file
      path: ca.stevestudios.Swirl.desktop
    • type: file
      path: ca.stevestudios.Swirl.svg
    • type: file
      path: ca.stevestudios.Swirl-symbolic.svg
    • type: file
      path: ca.stevestudios.Swirl.appdata.xml
  • name: swirl-bin
    buildsystem: cmake-ninja
    • -DCMAKE_BUILD_TYPE=Release
    • type: archive
      path: swirl-bin.tar.gz

…where swirl-bin is the Qt app source code.

qt.qpa.qgnomeplatform: Could not find color scheme “”
QQmlApplicationEngine failed to load component

It’s also worth mentioning that these errors (or maybe warnings) appear right before the main problem I have just described.

I am starting to think it is a bug with the base app (Not only am I sure I’ve tried everything in my power, but there is zero info on the web about this issue). I made an issue here: QtWebEngine import not found in QML · Issue #290 · flathub/io.qt.qtwebengine.BaseApp · GitHub

Also, it seems to only be a problem in QML, the C++ headers work fine.