vspreview not compatible with PyQt5 >=5.15.4

[Ichunjo]

Here is the tracelog

run script.py
Traceback (most recent call last):
  File "C:\Users\Varde\AppData\Roaming\Python\Python39\Scripts\vapoursynth-preview\run.py", line 2, in <module>
    from vspreview import main
  File "C:\Users\Varde\AppData\Roaming\Python\Python39\Scripts\vapoursynth-preview\vspreview\__init__.py", line 1, in <module>
    from .main import main
  File "C:\Users\Varde\AppData\Roaming\Python\Python39\Scripts\vapoursynth-preview\vspreview\main.py", line 12, in <module>
    from vspreview.core import (
  File "C:\Users\Varde\AppData\Roaming\Python\Python39\Scripts\vapoursynth-preview\vspreview\core\__init__.py", line 1, in <module>
    from .abstracts import (
  File "C:\Users\Varde\AppData\Roaming\Python\Python39\Scripts\vapoursynth-preview\vspreview\core\abstracts.py", line 19, in <module>
    class AbstractMainWindow(Qt.QMainWindow, QAbstractYAMLObjectSingleton):
AttributeError: module 'PyQt5.Qt' has no attribute 'QMainWindow

Maybe because it's deprecated? I took a look at the doc and it seems to be PyQt5.QtWidgets.QMainWindow now.

[Endilll]

Are there any symbols present in PyQt5.Qt?
I've been using 5.15.4 myself, and I never ran into such issue.
I can't find anything about it being deprecated in PyQt5 documentation, too.

[Ichunjo]

Are there any symbols present in PyQt5.Qt?

Hum, I don't know... I can't open Qt.pyd nor find it in the docs.

I can't find anything about it being deprecated in PyQt5 documentation, too.

I can't find anything about QMainWindow implemented in PyQt5.Qt though. All the examples I find on internet use PyQt5.QtWidgets.QMainWindow.

[Endilll]

I mean output of dir(PyQt5.Qt) after importing PyQt5.Qt.
Qt is a convenience module that supposed to just import everything from QtCore, QtGui, QtWidgets and so on, so users don't have to remember which part of the Qt every class belongs to.

[Ichunjo]

dir(PyQt5.Qt)
Same error with 5.15.4
5.15.3 import all components correctly.

Also, I'm not sure if it can be related but doing clean installs give me this:

pip install PyQt5==5.15.3
Installing collected packages: PyQt5-sip, PyQt5-Qt, PyQt5
Successfully installed PyQt5-5.15.3 PyQt5-Qt-5.15.2 PyQt5-sip-12.9.0

pip install PyQt5==5.15.4
Installing collected packages: PyQt5-sip, PyQt5
Successfully installed PyQt5-5.15.4 PyQt5-sip-12.9.0

PyQt5-Qt isn't installed with 5.15.4 and even installing it manually afterward doesn't fix it...

[Ichunjo]

Okay, when installing the lastest version of PyQt5, pip3.9 checks on python38 folder too

C:\>pip install PyQt5 --user
Collecting PyQt5
  Downloading PyQt5-5.15.4-cp36.cp37.cp38.cp39-none-win_amd64.whl (6.8 MB)
     |████████████████████████████████| 6.8 MB 6.8 MB/s
Requirement already satisfied: PyQt5-Qt5>=5.15 in c:\program files\python38\lib\site-packages (from PyQt5) (5.15.2)
Collecting PyQt5-sip<13,>=12.8
  Downloading PyQt5_sip-12.9.0-cp39-cp39-win_amd64.whl (63 kB)
     |████████████████████████████████| 63 kB 938 kB/s
Installing collected packages: PyQt5-sip, PyQt5
Successfully installed PyQt5-5.15.4 PyQt5-sip-12.9.0

See the line Requirement already satisfied: PyQt5-Qt5>=5.15 in c:\program files\python38\lib\site-packages (from PyQt5) (5.15.2)

I deleted the folders and it works now. Sorry about that

[Endilll]

I ran pip install -r requirements.txt on a machine with almost clean python 3.9 installation (no traces of Qt), and got all three PyQt5-5.15.4, PyQt5_Qt5-5.15.2, and QtPy-1.9.0. VSP runs just fine on that machine now.