A short example of how to override sys.excepthook to get exception out of pyqt

qt_exception_decorator.py

from PyQt4 import QtGui
import time
#app = QtGui.QApplication([])
class exception_munger(object):
    def __init__(self):
        self.flag = True
        self.txt = ''
        self.type = None

    def indicate_fail(self,etype=None, txt=None):
        self.flag = False
        if txt is not None:
            self.txt = txt
        self.type = etype
    def reset(self):

        tmp_txt = self.txt
        tmp_type = self.type
        tmp_flag = self.flag
        self.flag = True
        self.txt = ''
        self.type = None
        return tmp_flag, tmp_type, tmp_txt

class e_manager():
    def __init__(self):
        self.old_hook = None
        
    def __enter__(self):
        em = exception_munger()
        def my_hook(type, value, tback):
            em.indicate_fail(type, value)
            sys.__excepthook__(type, value, tback) 
        self.old_hook = sys.excepthook
        sys.excepthook = my_hook
        self.em = em
        return self
    
    def __exit__(self,*args,**kwargs):
        sys.excepthook = self.old_hook
    
def mang_fac():
    return e_manager()
    
def assert_dec(original_fun):

    def new_fun(*args,**kwargs):
        with mang_fac() as mf:
            res = original_fun(*args, **kwargs)
            flag, etype, txt = mf.em.reset()
            if not flag:
                raise etype(txt)
            return res
    return new_fun

@assert_dec
def my_test_fun():
    dialog = QtGui.QDialog()
    button = QtGui.QPushButton('I crash')
    layout = QtGui.QHBoxLayout()
    layout.addWidget(button)
    dialog.setLayout(layout)
    def crash(): 
        time.sleep(1)
        raise Exception('Crash!')
    button.clicked.connect(crash)


    button.click()

my_test_fun()
print 'should not happen'