QSpinBox.setValue doesn't redraw window properly

[laughingrice]

I am using pyqt 5.12.3 from anaconda on osx Catalina
This problem seems to be specific to mac as I do not see it on Linux (do not have a windows system to test)

Updating a QSpinBox by calling setValue does not seem to properly delete previous content which is only partially drawn over. Switching to another desktop and back does seem to force a redraw, also clicking with the mouse inside the box.

Example (set value of 8 over previous 0)

Any ideas if this is a known problem or if I'm doing something wrong in the code?

Thanks

This is a minimal python file:

import sys
from PyQt5 import QtWidgets, QtCore

class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, ):
        super().__init__()

        self.spin = QtWidgets.QSpinBox(self)
        self.spin.move(50,50)

        self.button = QtWidgets.QPushButton('button', self)
        self.button.move(50, 100)
        self.button.clicked.connect(self.on_click)

    def on_click(self):
        v = self.spin.value()
        
        if v == 0:
            self.spin.setValue(8)
        else:
            self.spin.setValue(0)

if __name__ == "__main__":
	app = QtWidgets.QApplication(sys.argv)
	window = MainWindow()
	window.show()
	sys.exit(app.exec_())

[kitchoi]

For anyone who comes across this... I could not reproduce the issue with PyQt 5.12.6 and OSX 10.15.5, but if I add a second button to go after the the spinbox in the layout, then I can reproduce:

import sys
from PyQt5 import QtWidgets, QtCore

print(QtCore.QT_VERSION_STR)


class MainWindow(QtWidgets.QWidget):
    def __init__(self, ):
        super().__init__()

        self.spin = QtWidgets.QSpinBox(self)

        self.button = QtWidgets.QPushButton('button', self)
        self.button.clicked.connect(self.on_click)

        self.button2 = QtWidgets.QPushButton('do nothing', self)

        VBox = QtWidgets.QVBoxLayout()
        VBox.addWidget(self.button)
        VBox.addWidget(self.spin)
        VBox.addWidget(self.button2)
        self.setLayout(VBox)

    def on_click(self):
        v = self.spin.value()
        if v == 0:
            self.spin.setValue(8)
        else:
            self.spin.setValue(0)

if __name__ == "__main__":
	app = QtWidgets.QApplication(sys.argv)
	window = MainWindow()
	window.show()
	sys.exit(app.exec_())

Then I was able to "fix" / "workaround" the issue by adding type=QtCore.Qt.QueuedConnection in the connect call, i.e. this:

        self.button.clicked.connect(self.on_click, type=QtCore.Qt.QueuedConnection)

[jeremy_k]

This might be related to https://bugreports.qt.io/browse/PYSIDE-871