vendor Qt is outdated and doesnt work with PySide6

[hannesdelbeke]

File "...\site-packages\pyblish_lite\vendor\Qt.py", line 1676, in _install
LogPython: Error:     raise ImportError("No Qt binding were found.")
LogPython: Error: ImportError: No Qt binding were found.

[mottosso]

Indeed, it'll need to pop in the new Qt.py and make a few tweaks to make it work. A PR would be lovely!

[aharjunmaa]

I was able to circumvent this error by simply copying the newest Qt.py module (v1.4.1) into the "vendor" directory to overwrite the old one. @mottosso, is this a sufficient solution?

[mottosso]

Yep, that's it!

[aharjunmaa]

Here's the PR:

#134

I'm not sure exactly what "few tweaks" are necessary; I did find one PySide6 bug that I fixed as well, and after that, our custom UI that is based on Pyblish Lite works as before the PySide6 update. More extensive testing may be necessary.

[ArlonSwaders]

@mottosso the vendorized Qt.py is great for studio's and users using Pyblish Lite out of the box. However, we are using Rez to add Qt.py to our environment. In that situation, the vendorized Qt.py module is actually a maintenance burned when moving to for example Maya 2025, as we now would need the vendor\Qt.py module to be updated as well.

Do you have any concerns to add the vendorized module as a fallback for when Qt.py is not in the environment already?

try:
    from Qt import QtCore
except ImportError:
    # Fall back to vendorized Qt.py
    from .vendor.Qt import QtCore

I'd be happy to open an PR for that.

[mottosso]

the vendorized Qt.py module is actually a maintenance burned

It definitely should not be. The vendored Qt.py is an implementation detail of Pyblish Lite and should have no effect on anything outside of it. It's entirely safe to ignore from a pipeline perspective.

[ArlonSwaders]

@mottosso I'm not sure if that means you agree with the above suggestion or not?

---

To demonstrate the problem, I'm loading a Rez environment with the following:

• maya-2025 (ships with PySide6)
• qt_py-1.4.1
• pyblish_lite-0.8.12

I run the following code in Maya to open the Pyblish Lite (normally we would use pyblish-maya):

import pyblish.api
guis = pyblish.api.registered_guis()

for gui in guis:
    __import__(gui).show()

This results in the following error:
# Error: ImportError: file /home/arlon.swaders/packages/pyblish_lite/0.8.13/site-packages/pyblish_lite/vendor/Qt.py line 1676: No Qt binding were found.

This despite the fact that we have Qt.py-1.4 in our environment, which already is compatible with PySide6.

My point here is that, in order for us to move to Maya 2025, we need to wait for this repo (an Pyblish Maya) to update their vendorized Qt.py. This could in my opinion be slowing us down more than needed to roll out a new Maya version.

Hence, my suggestion to allow Pyblish Lite to pick up an external Qt.py, and fall back to the vendorized module when no external one is available.