Qt6 (QGIS 4) compatibility

[signedav]

Qt6 upgrade performed by pyqgis4-checker:

docker run -it --rm -v /home/dave/dev/opengisch/QgisModelBaker:/home/pyqgisdev/ registry.gitlab.com/oslandia/qgis/pyqgis-4-checker/pyqgis-qt-checker:latest pyqt5_to_pyqt6.py --logfile /home/pyqgisdev/pyqt6_checker.log .

See https://github.com/qgis/QGIS/wiki/Plugin-migration-to-be-compatible-with-Qt5-and-Qt6 and https://github.com/qgis/pyqgis4-checker

Requires opengisch/QgisModelBakerLibrary#144

For big parts this resolves #985

Manual checks

• Removed Modules in Qt 6.0
• Changes to Qt Modules in Qt 6
• Qt Namespace, all enums in Qt
• overview of the differences between PyQt6 and PyQt5 (https://www.riverbankcomputing.com/static/Docs/PyQt6/pyqt5_differences.html)

Test manually

Docker approach

docker build --pull --rm -f qgis-qt6-unstable.dockerfile     --progress=plain     --build-arg QGIS_GIT_VERSION=master     -t qgis-qt6-unstable:local .

and:

xhost +local:docker

and:

docker run -it --rm   -e DISPLAY=$DISPLAY   -e LC_ALL=C.utf8   -e LANG=C.utf8   -v /tmp/.X11-unix:/tmp/.X11-unix     -v /home/dave/.local/share/QGIS/QGIS3/profiles/modelbaker:/home/quser/.local/share/QGIS/QGIS3/profiles/default qgis-qt6-unstable:local   qgis

with:

-v /home/dave/.local/share/QGIS/QGIS3/profiles/modelbaker:/home/quser/.local/share/QGIS/QGIS3/profiles/default

but does not work

Flatpack approach

Got flatpack from http://duif.net/qgis-qt6.flatpak

And this works...

Results

• Deprecated FollowREdirectsattribute mode -> could be skipped when Qt6 (but not with Qt5)

• setFilterRegularExpression replaces setFilterRegExp

• The gui is f... up. Sizes are not correct. (Test here on the other computer)

• Could not test Java interaction with flat pack (it says no java is installed)

• Do we need to support Qt < 5.12? (if so,then we need setFilterRegExp)