Failing to start on Linux Fedora 38 - Solved

[ilippert]

Describe the bug
Unfortunately, QualCoder does not start.

Desktop (please complete the following information):

• Fedora Linux 38

Error message
No module named 'vlc'
No module named 'vlc'
No module named 'vlc'
No module named 'vlc'
No module named 'vlc'
No module named 'vlc'
No module named 'vlc'
No module named 'vlc'
No module named 'vlc'
qt.qpa.plugin: Could not find the Qt platform plugin "wayland" in ""
qt.qpa.plugin: Could not find the Qt platform plugin "xcb" in ""
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

[ccbogel]

Hmm.
I wonder if this will fix on of the errors:
sudo dnf install xcb-util*

I saw the suggestion here: https://stackoverflow.com/questions/68036484/qt6-qt-qpa-plugin-could-not-load-the-qt-platform-plugin xcb-in-even-thou

For the other try this:
sudo dnf install qt-wayland

I dont have Fedora to test. But I read there are lots of this type of problem raised with qt5 and qt6 and wayland on Fedora

[ilippert]

Thanks a lot, yes, sudo is used for installing packages via dnf. I have both xcb-util and qt-wayland installed on the system.

as for the vlc module error, this might help: https://stackoverflow.com/questions/38265773/import-vlc-module-in-python

From https://unix.stackexchange.com/questions/598099/could-not-find-the-qt-platform-plugin-wayland I get
Also set QT_QPA_PLATFORM=wayland;xcb if the application misbehaves in wayland

Might these pointers help?

[ccbogel]

The VLC notification is not really an error, and can be ignored, QC should still run. I am presuming you do not have vlc installed.
But you can try:
python3 -m pip install python-vlc
And if that works ok - add this to the Fedora set up shell script

[ccbogel]

To start the program - I presume you use terminal to start qualcoder:
e,g, like this:
python3 -m qualcoder
Can you set the environment variable when starting the program, like this:

QT_QPA_PLATFORM=wayland python3 -m qualcoder
or
set QT_QPA_PLATFORM=wayland python3 -m qualcoder

or

QT_QPA_PLATFORM=wayland;xcb python3 -m qualcoder

or
set QT_QPA_PLATFORM=wayland;xcb python3 -m qualcoder

Please let me know

[ilippert]

Thanks, I comment below in detail.

QT_QPA_PLATFORM=wayland python3 -m qualcoder

results in

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.

QT_QPA_PLATFORM=wayland;xcb python3 -m qualcoder

results in

bash: xcb: command not found...

So, I tried QT_QPA_PLATFORM=xcb python3 -m qualcoder and that results in

qt.qpa.plugin: Could not find the Qt platform plugin "xcb" in ""
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

[frukto]

I had a similar issue, but rerunning install_fedora.sh after upgrading from F36 fixed the issue for me. I am getting the vlc messages though.

[ilippert]

I had a similar issue, but rerunning install_fedora.sh after upgrading from F36 fixed the issue for me. I am getting the vlc messages though.

python3 -m pip install python-vlc should do the work - at least it did for me. And I have now proposed it for the install_fedora.sh file via #795.

Could you check which xcb packages you have installed on your system?

[frukto]

Let me know if you need more info.

$ dnf list --installed | grep xcb
libX11-xcb.x86_64                                    1.8.4-1.fc38                        @fedora                
libxcb.x86_64                                        1.13.1-11.fc38                      @fedora                
libxcb-devel.x86_64                                  1.13.1-11.fc38                      @fedora                
xcb-util.x86_64                                      0.4.1-2.fc38                        @fedora                
xcb-util-cursor.x86_64                               0.1.4-2.fc38                        @fedora                
xcb-util-image.x86_64                                0.4.1-2.fc38                        @fedora                
xcb-util-keysyms.x86_64                              0.4.1-2.fc38                        @fedora                
xcb-util-renderutil.x86_64                           0.3.10-2.fc38                       @fedora                
xcb-util-wm.x86_64                                   0.4.2-2.fc38                        @fedora      

And yes, python3 -m pip install python-vlc let the warinings disapear. Thx.

[ccbogel]

The Fedora shell script has updated that line, thx ilippiert

[ilippert]

Let me know if you need more info.

Hmm, I also have all these packages installed. Will have to install a freh Fedora version and see whether QualCoder runs then.

[ilippert]

Hi, hmm, still problem, now with this trouble:

Traceback (most recent call last):
  File "/usr/local/bin/qualcoder", line 33, in <module>
    sys.exit(load_entry_point('Qualcoder==3.4', 'console_scripts', 'qualcoder')())
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/bin/qualcoder", line 25, in importlib_load_entry_point
    return next(matches).load()
           ^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib64/python3.11/importlib/metadata/__init__.py", line 202, in load
    module = import_module(match.group('module'))
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib64/python3.11/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1204, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1176, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1147, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 690, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 940, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "/usr/local/lib/python3.11/site-packages/Qualcoder-3.4-py3.11.egg/qualcoder/__main__.py", line 48, in <module>
    from PyQt6 import QtCore, QtGui, QtWidgets
ImportError: /lib64/libQt6Core.so.6: version `Qt_6_PRIVATE_API' not found (required by /usr/local/lib/python3.11/site-packages/PyQt6-6.5.1-py3.11-linux-x86_64.egg/PyQt6/QtCore.abi3.so)

Do you have any idea what is wrong here?

[ccbogel]

I don't know why this is happening. It happened to me when I upgraded from one version of Ubuntu to the next. What I did was a complete re-install of the newer Ubuntu version. Then install all the python bits I needed, to make it work.

[bzwierz]

Hi, hmm, still problem, now with this trouble:

Traceback (most recent call last):
  File "/usr/local/bin/qualcoder", line 33, in <module>
    sys.exit(load_entry_point('Qualcoder==3.4', 'console_scripts', 'qualcoder')())
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/bin/qualcoder", line 25, in importlib_load_entry_point
    return next(matches).load()
           ^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib64/python3.11/importlib/metadata/__init__.py", line 202, in load
    module = import_module(match.group('module'))
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib64/python3.11/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1204, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1176, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1147, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 690, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 940, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "/usr/local/lib/python3.11/site-packages/Qualcoder-3.4-py3.11.egg/qualcoder/__main__.py", line 48, in <module>
    from PyQt6 import QtCore, QtGui, QtWidgets
ImportError: /lib64/libQt6Core.so.6: version `Qt_6_PRIVATE_API' not found (required by /usr/local/lib/python3.11/site-packages/PyQt6-6.5.1-py3.11-linux-x86_64.egg/PyQt6/QtCore.abi3.so)

Do you have any odea what is wrong here?

Same here. Have you found any solutions?

[ccbogel]

I don't know how to fix this in Fedora. I did have a similar issue when I upgraded Ubuntu. The solution for me was anew install of Ubuntu.

[ilippert]

Hmm, I reinstalled Fedora and that did not help.

[ilippert]

Now, following https://stackoverflow.com/questions/70677148/sudden-importerror-cannot-import-name-qtcore-from-pyqt5, as a normal user I executed python3 -m pip install --upgrade --force-reinstall PyQt6. Then reran the Qualcoder Fedora install script. Then it worked.

well, and before I ran sudo dnf install ffmpeg --allowerasing because the ffmpeg installation did not succeed.

[ccbogel]

Oh that;s good. Thank you for solving the problem. I will leave this post here so others can see it. and I might add to the instructions also.

[ilippert]

Hi, I checked the issue and solution on another Fedora system, too.
I confirm the #794 (comment) solution:

1. as a normal user, execute python3 -m pip install --upgrade --force-reinstall PyQt6.
2. Then run the QualCoder Fedora install script.