使用cython编译代码后无法运行pyqt5 app

Question

Here is a simple PyQt5 application. There is a QCheckBox in it and I connected its clicked signal to foo() function. By clicking on this checkbox I pass two parameters to the foo() function and print those parameters to the console. It works fine however after I compile this code using cython compiler by clicking on this checkbox I get a TypeError .

main.py:

from PyQt5.QtWidgets import QMainWindow, QApplication, QCheckBox
from functools import partial
import sys

class MainWindow(QMainWindow):
    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)
        self.chb = QCheckBox(self)
        self.chb.setText('My CheckBox')
        self.chb.move(10, 10)
        self.chb.clicked.connect(
            partial(self.foo, 'para1', 'para2')
        )

    def foo(self, p1, p2):
        print(p1, p2)


def main():
    app = QApplication(sys.argv)
    win = MainWindow()
    win.show()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

Error:

Traceback (most recent call last):
  File "main.pyx", line 15, in main.MainWindow.foo
    def foo(self, p1, p2):
TypeError: foo() takes exactly 3 positional arguments (4 given)

setup.py:

from setuptools import setup
from Cython.Build import cythonize

setup(ext_modules = cythonize("main.pyx"))

I'm using python 3.7 on a windows 10 machine.

Cython==0.29.24 and PyQt5==5.15.4

Answer 1

It seems that when cythonized the default argument is sent, so a possible solution is to pass that argument to it:

def foo(self, p1, p2, checked):
    print(p1, p2)

Another option is not to use functools.partial but rather nested functions:

class MainWindow(QMainWindow):
    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)
        self.chb = QCheckBox(self)
        self.chb.setText("My CheckBox")
        self.chb.move(10, 10)
        self.chb.clicked.connect(self.foo('para1', 'para2'))

    def foo(self, p1, p2):
        def wrapper():
            print(p1, p2)

        return wrapper