PyQt事件处理程序snarf异常 [英] PyQt event handlers snarf exceptions

问题描述

以下是说明问题的代码：

Here's the code that illustrates the problem:

from PyQt4 import QtGui
app = QtGui.QApplication([])
dialog = QtGui.QDialog()
button = QtGui.QPushButton('I crash')
layout = QtGui.QHBoxLayout()
layout.addWidget(button)
dialog.setLayout(layout)
def crash(): raise Exception('Crash!')
button.clicked.connect(crash)
button.click()
print 'I should not happen'

当我运行它，PyQt4处理我的错误。我的控制台在其中显示一个堆栈跟踪，其中包含Crash！等，我看到我不应该发生。

When I run that, PyQt4 handles the error for me. My console displays a stack trace with 'Crash!' etc. in it, and I see 'I should not happen'.

这没有用，因为我被许多处理程序提交了大量的应用程序，我需要将所有的错误强制到我的脸上（并进入我的自动化测试）。每次运行时，错误都会逃离我的网络，而且它们需要过多的无用的尝试：除了每个处理程序中的块之外，只需要抓住它们。

This is not useful, because I've been handed a large application with many handlers, and I need to force all their errors up into my face (and into my - ahem - automated tests). Each time I run, errors escape my nets, and they would require excessive and useless try:except blocks, inside every handler, just to catch them all.

换句话说，我希望好的代码是非常好的，坏的代码是非常糟糕的。不要粉饰。

Put another way, I want good code to be very good, and bad code to be very bad. Not whitewashed.

如果这是已经被问到，抱歉，但是当我搜索它时，我自然会得到成千上万的新手来询问基本的错误处理问题（或者更糟的是，我得到新手询问如何关闭他们的方式异常！;）

Apologies if this is already asked, but when I e-search for it, I naturally get thousands of newbies asking basic error handling questions (or, worse, I get newbies asking how to turn OFF their wayward exceptions!;)

如何覆盖PyQt4的默认错误处理，所以我可以自己传播或记录错误？请不要回答sys.excepthook，它会捕获PyQt4 不会捕获的错误。

How do I override PyQt4's default error handling, so I can propagate or log errors myself? And please don't answer sys.excepthook, either - it catches the errors that PyQt4 doesn't catch.

推荐答案

我认为答案是，这不是 PyQt 的功能，而是让信号/插槽工作的设计所固有的结果（记住信号/插槽通信也正在通过c ++层）。

I think the answer is that this isn't a 'feature' of PyQt, but a consequence inherent to the design that lets signals/slots work (remember that the signal/slot communication is going through a c++ layer as well).

这是丑陋的，但是在您的问题上做了一些并且终止运行

This is ugly, but does a bit of and end-run around your problem

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'

这不会打印不应该发生，并给你一些东西赶上你的自动化测试使用正确的异常类型）。

This will not print 'should not happen' and gives you something to catch with your automated tests (with the correct exception type).

In [11]: Traceback (most recent call last):
  File "/tmp/ipython2-3426rwB.py", line 68, in crash
Exception: Crash!
---------------------------------------------------------------------------
Exception                                 Traceback (most recent call last)
<ipython-input-11-6ef4090ab3de> in <module>()
----> 1 execfile(r'/tmp/ipython2-3426rwB.py') # PYTHON-MODE

/tmp/ipython2-3426rwB.py in <module>()

/tmp/ipython2-3426rwB.py in new_fun(*args, **kwargs)

Exception: Crash!

In [12]: 

堆栈跟踪被提升，但您仍然可以阅读打印出来的第一个。

The stack trace is jacked up, but you can still read the first one that was printed out.

这篇关于PyQt事件处理程序snarf异常的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！