PyQt6 port might not work on Raspberry Pi

[carlosperate]

After the Mu 1.2 release we are planning to move to PyQt6.

Problem

For the Raspberry Pi we depend on the python3-PyQt5 apt packages being available, for both the deb installer and pip installation.

The python3-PyQt6 pacakges will only be avialble in the next Ubuntu Kinetic 22.10 release and Debian Bookworm, which doesn't have a release date yet:

• Ubuntu Kinetic: https://packages.ubuntu.com/kinetic/python3-pyqt6
  • Doesn't exists for 22.04, this is a 404: https://packages.ubuntu.com/jammy/python3-pyqt6:
• Debian Bookworm: https://packages.debian.org/bookworm/python3-pyqt6
  • Doesn't exists for Buster, this is a 404: https://packages.debian.org/buster/python3-pyqt6

As Riverbank does't provide Python wheels for Arm targets, and pywheels doesn't have a recipe to build PyQt from source, installing in Raspberry Pi is not possible without the debian packages.

There also isn't packages for python3-pyqt5.qsci nor python3-pyqt5.qtchart. Technically QtCharts is options still in the codebase, but QScintilla is essential for Mu.

Possible Solution

The only options I can see right now:

• Not support Raspberry Pi until the Raspberry Pi OS based on Bookworm is released, or the Debian packages are available
  • This can take a few years, so I really hope it doesn't come down to this
• Keep the codebase compatible with PyQt 5 and 6, use PyQt5 in Arm and PyQt6 everywhere else
  • We'll need to keep the environmnetal markers in setup.py to not install either on Arm, and as we currently, we'll depend on the PyQt5 Python package being installed via apt
• Maintain an old branch of v1.2.x, and possible backport important bug fixes.
• Any other ideas?