[Preventing PyQt to silence exceptions occurring in slots] +100 Can create a decorator that wraps PyQt' new signal/slot decorators and provides exception handling for all slots. Can also override QApplication::notify to catch uncaught C++ exceptions.

silence_exception.py

import sys
import traceback
import types
from functools import wraps
from PyQt5 import QtGui, QtCore, QtWidgets

def MyPyQtSlot(*args):
    if len(args) == 0 or isinstance(args[0], types.FunctionType):
        args = []
    @QtCore.pyqtSlot(*args)
    def slotdecorator(func):
        @wraps(func)
        def wrapper(*args, **kwargs):
            try:
                func(*args)
            except:
                print ("Uncaught Exception in slot")
                traceback.print_exc()
        return wrapper

    return slotdecorator

class Test(QtWidgets.QPushButton):
    def __init__(self, parent=None):
        QtWidgets.QWidget.__init__(self, parent)
        self.setText("hello")
        self.clicked.connect(self.buttonClicked)

    @MyPyQtSlot("bool")
    def buttonClicked(self, checked):
        print ("clicked")
        raise Exception("wow")

class MyApp(QtWidgets.QApplication):
    def notify(self, obj, event):
        isex = False
        try:
            return QtWidgets.QApplication.notify(self, obj, event)
        except Exception:
            isex = True
            print ("Unexpected Error")
            print (traceback.format_exception(*sys.exc_info()))
            return False
        finally:
            if isex:
                self.quit()

app = MyApp(sys.argv)

t=Test()
t.show()
try:
    app.exec_()
except:
    print ("exiting")