PR: More fixes for Qt 6 compatibility and a PySide2 fix

[rear1019]

Description of Changes

Fixes for Qt 6 compatibility, a PySide2 fix and removal of a Qt 4 check.

Note:

• PyQt6: Spyder does not start. It can be fixed either in pyqt or in spyder. I will provide more information later.
• PySide6: Doesn’t work (yet). PySide6 >= 6.5 finally supports super() [1], however, it is flawed (in the sense that it works differently than in PyQt, see [2]). But: I do have some workarounds which allow the GUI to show up, that is, it looks promising after all.

[1] Partially only, in __init__(), which suffices as far as Spyder is concerned.
[2] https://bugreports.qt.io/browse/PYSIDE-2573

Affirmation

By submitting this Pull Request or typing my (user)name below,
I affirm the Developer Certificate of Origin
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and understand I am releasing the same under Spyder's MIT (Expat) license.

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rear10

[pep8speaks]

Hello @rear1019! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2024-01-24 13:51:37 UTC

[rear1019]

PyQt6: Spyder does not start. It can be fixed either in pyqt or in spyder. I will provide more information later.

The same issue also affects PySide6. See spyder-ide/qtpy#473 for details.

[ccordoba12]

Thanks @rear1019 for your help with this!

All my suggestions are related to the style issues found by pep8 speaks. The rest looks good to me.

[ccordoba12]

The same issue also affects PySide6. See spyder-ide/qtpy#473 for details.

I took a look at our git history and it's not clear what's the purpose of FakeApplication. However, we wouldn't need to do any changes in QtPy if we remove its exec_ method, right?

If that's the case, then please only remove that method in this PR to see if our tests pass.

[ccordoba12]

@rear1019, I think the only missing thing here is to remove the FakeApplication.exec_ method.

[rear1019]

@rear1019, I think the only missing thing here is to remove the FakeApplication.exec_ method.

@ccordoba12 Sorry for the late reply. I wanted to check something, and something personal came up. Anyway:

The same issue also affects PySide6. See spyder-ide/qtpy#473 for details.

I took a look at our git history and it's not clear what's the purpose of FakeApplication.

Yes, that’s what I figured as well.

However, we wouldn't need to do any changes in QtPy if we remove its exec_ method, right?

Doing that alone won’t help: During startup, create_application() [1] creates [2] a SpyderApplication (which derives from QApplication), performs the monkey patching [3] and returns the SpyderApplication instance. Note that SpyderApplication is a subclass of the original QApplication, not the monkey patched FakeApplication. Later on the original exec_() is called, which is an alias to possibly_static_exec() [4]. That helper function makes use of isinstance(), which is now confused by the monkey patch.

I have pushed a commit which completely removes FakeApplication and the monkey patch.

[1]

spyder/spyder/app/utils.py

Line 270 in e624b70

def create_application():

[2]

spyder/spyder/app/utils.py

Line 273 in e624b70

app = qapplication()

[3]

spyder/spyder/app/utils.py

Line 314 in e624b70

QtWidgets.QApplication = FakeQApplication

[4] https://github.com/spyder-ide/qtpy/blob/f8f3422a2c8dac3cc235f79d0d1db28d5dd1cf1c/qtpy/_utils.py#L45

[ccordoba12]

Thanks for your thorough investigation @rear1019! Since FakeApplication doesn't seem really necessary, I agree with removing it.

[ccordoba12]

Thank @rear1019 for all your efforts to get us ready for Qt6!