Apparently it is a bug to be using qtwebkit.

https://doc.qt.io/qt-5/qtwebenginewidgets-qtwebkitportingguide.html

@gdt what QGIS version are you running there ?

QGIS 3.34.13-Prizren 'Prizren' (exported)

@gdt I tried to check where we are using qtwebkit and did a PR, could you check if that resolves the issue for you? If not could you please install the https://plugins.qgis.org/plugins/firstaid/ and share with me the stack trace you get when you try to start the plugin

I uninstalled the released version of the plugin. I cloned the repo and checked out the webkit branch. i zipped it up, and did install plugin from zip. It still fails, but with firstaid I have more insight.

In utilities.py, get_ui_class, the try/except around the import

from PyQt5.QtWebEngineWidgets import QWebEngineView

ends up setting the variables according to the else branch. That seems wrong, but I edited the code to not import and just use the webengine tokens, so I/we can debug why the import fails separately.

After forcing to QWebEngineView, I still got an import error:

cannot import name 'QtWebKitWidgets' from 'PyQt5' (/usr/pkg/lib/python3.12/site-packages/PyQt5/__init__.py)

and looking at local variables I see that nothing was substituted into ui_file_path and I don't understand how that is supposed to work.

ui_file_path = {str} '/home/gdt/.local/share/QGIS/QGIS3/profiles/default/python/plugins/parcel_plugin/ui_crsselector.ui

In ui_crsselector.ui I still find

 <customwidgets>
  <customwidget>
    <class>QWebView</class>
    <extends>QWidget</extends>
    <header>PyQt4.QtWebKit</header>
  </customwidget>

@gdt Can you please make sure that the QWebEngineView is installed. Try the following:

• Delete the old ./__pycache__ folder

• Open the QGIS console and type the following

import pip
pip.main(['install', 'PyQtWebEngine'])

Then you can run the import

from PyQt5.QtWebEngineWidgets import QWebEngineView

I did not explicitly clear pycache (in the parcel_plugin dir) but the mod times all track the sources.

I can run that import from system python with no errors. I am using qgis packaged in pkgsrc, where all the python modules are in the system load path.

$ ls -l /usr/pkg/lib/python3.12/site-packages/PyQt5/QtWebEngine*
-rwxr-xr-x  1 root  wheel   92072 Dec 29 08:53 /usr/pkg/lib/python3.12/site-packages/PyQt5/QtWebEngine.abi3.so
-rwxr-xr-x  1 root  wheel  178920 Dec 29 08:53 /usr/pkg/lib/python3.12/site-packages/PyQt5/QtWebEngineCore.abi3.so
-rwxr-xr-x  1 root  wheel  417008 Dec 29 08:53 /usr/pkg/lib/python3.12/site-packages/PyQt5/QtWebEngineWidgets.abi3.so

I see lots of (c++ mangled) symbols that make sense.

But, progress in diagnosing: I opened the python console and pasted it, and got:

# Python Console
# Use iface to access QGIS API interface or type '?' for more info
# Security warning: typing commands from an untrusted source can harm your computer
>>> from PyQt5.QtWebEngineWidgets import QWebEngineView
Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "/usr/pkg/share/qgis/python/qgis/utils.py", line 892, in _import
    mod = _builtin_import(name, globals, locals, fromlist, level)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ImportError: QtWebEngineWidgets must be imported or Qt.AA_ShareOpenGLContexts must be set before a QCoreApplication instance is created

qgis/QGIS#49512 seems relevant.

I did not explicitly clear pycache (in the parcel_plugin dir) but the mod times all track the sources.

I can run that import from system python with no errors. I am using qgis packaged in pkgsrc, where all the python modules are in the system load path.

$ ls -l /usr/pkg/lib/python3.12/site-packages/PyQt5/QtWebEngine*
-rwxr-xr-x  1 root  wheel   92072 Dec 29 08:53 /usr/pkg/lib/python3.12/site-packages/PyQt5/QtWebEngine.abi3.so
-rwxr-xr-x  1 root  wheel  178920 Dec 29 08:53 /usr/pkg/lib/python3.12/site-packages/PyQt5/QtWebEngineCore.abi3.so
-rwxr-xr-x  1 root  wheel  417008 Dec 29 08:53 /usr/pkg/lib/python3.12/site-packages/PyQt5/QtWebEngineWidgets.abi3.so

I see lots of (c++ mangled) symbols that make sense.

But, progress in diagnosing: I opened the python console and pasted it, and got:

# Python Console
# Use iface to access QGIS API interface or type '?' for more info
# Security warning: typing commands from an untrusted source can harm your computer
>>> from PyQt5.QtWebEngineWidgets import QWebEngineView
Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "/usr/pkg/share/qgis/python/qgis/utils.py", line 892, in _import
    mod = _builtin_import(name, globals, locals, fromlist, level)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

I also had the same issue before I installed it with pip. I haven't tested the 3D stuff to see if it still works after my pip install.

ImportError: QtWebEngineWidgets must be imported or Qt.AA_ShareOpenGLContexts must be set before a QCoreApplication instance is created

The other solution would be extensive to refactor the UI selector to use something else if QtWebEngineView and Qt 3d cannot be used at the same time.

I'm not sure if there is anything else that I should be testing for you, guessing not at this point. It looks like this will be difficult to fix, and I get it things get fixed when someone has enough time and spends it -- so I'm guessing this issue will just remain open until that happens. I'm subscribed to the ticket of course, so feel free to ask me to test if that's helpful.