Various Issues with PyQt6

[Phil Thompson]

On 26/02/2021 04:13, RoadrunnerWMC wrote:
> Hi again Phil,
> 
> I just installed PyQt 6.0.2. The problems from my previous email are 
> fixed
> now (thanks!) and my application is able to launch. I am having a few 
> new
> issues now, though.
> 
> Here's the main one:
> 
>     from PyQt6 import QtCore, QtGui, QtWidgets
>     app = QtWidgets.QApplication([])
> 
>     mbox = QtWidgets.QMessageBox()
>     mbox.setStandardButtons(QtWidgets.QMessageBox.StandardButtons.Yes |
> QtWidgets.QMessageBox.StandardButtons.No)
>     ret = mbox.exec()
> 
>     # The return value is an integer, but
> QtWidgets.QMessageBox.StandardButtons
>     # can't be converted or compared to integers.
> 
>     # This prints False no matter which button you clicked:
>     print(ret == QtWidgets.QMessageBox.StandardButtons.Yes)
> 
>     # TypeError: int() argument must be a string, a bytes-like object 
> or a
> number, not 'StandardButtons'
>     int(QtWidgets.QMessageBox.StandardButtons.Yes)
> 
>     # TypeError: unsupported operand type(s) for &: 'int' and
> 'StandardButtons'
>     print(ret & QtWidgets.QMessageBox.StandardButtons.Yes)
> 
> As far as I can tell, there's no way to check the return value of
> `QtWidgets.QMessageBox.exec()` without hardcoding integer values 
> (yuck).
> One way to fix it would be to change `.exec()`'s return type to
> `QtWidgets.QMessageBox.StandardButtons`, but since the integer values 
> of
> the enum are officially publicly documented (
> https://doc.qt.io/qt-6/qmessagebox.html#StandardButton-enum), my guess 
> is
> that adding support for int comparisons to the `StandardButtons` class
> would be a better solution. Or maybe there already is a way to do this
> comparison and I just don't see it?

That will be fixed in the next snapshot.

> A second issue:
> 
>     from PyQt6 import QtCore, QtGui, QtWidgets
>     app = QtWidgets.QApplication([])
>     folder = QtWidgets.QFileDialog.getExistingDirectory(None, 'Select a
> folder')
>     print(folder)
> 
> For whatever reason, this actually creates a *file*-selection dialog, 
> which
> doesn't let me choose a folder. (Platform is KDE Neon (Ubuntu 20.04), 
> if it
> helps.)

I've only tested on macOS but that puts up the correct dialog so it is 
unlikely to be a PyQt issue.

> One more issue I found on 6.0.1 after my previous email -- though
> unfortunately without a way to trigger it consistently -- is that 
> sometimes
> `QMainWindow.restoreState()` or `QMainWindow.restoreGeometry()` (not 
> sure
> which) crashes if the pre-existing state (or geometry) was saved by 
> PyQt5.
> 
> The best workaround I can think of is to append the PyQt version name
> ("PyQt5"/"PyQt6") to the application name passed to the QSettings
> constructor, thus preventing PyQt6 from ever trying to read PyQt5's
> settings and vice versa. Luckily, my application has very few settings 
> and
> I don't expect anyone to switch back and forth between PyQt versions, 
> so
> this won't be a big problem. It's still not really ideal, though.
> 
> Is this crash considered a bug? If not, is there a better way for me to
> handle this situation?

Again I can't see how that is a PyQt issue rather than a Qt issue.

Phil