[Twisted-Python] Hanging test cases (Was: Evangelism notes...)

[Bob Ippolito]

On May 5, 2005, at 3:05 PM, Grant Baillie wrote:

>
> On May 5, 2005, at 11:49 AM, Grant Baillie wrote:
>
>
>> So far as I can tell, the python threading module has an atexit  
>> handler that's hanging. Also, if I replace the deferToThread()  
>> with a twisted.web.client.getPage(), I still get the same hang.
>>
>
> Er, I'd already replaced the deferToThread() in an earlier version  
> of that file with twisted.web.client.getPage(), for anyone  
> following along at home.
>
> I also found a hackaround, which is to insert the following before  
> the call to getPage:
>
> #---------------
> import threading
> # threading seems to install an atexit() handler that
> # can wedge if you've run the reactor. So, we import it
> # first....
>
> import atexit
>
> def runAndStop():
>     if not reactor.running:
>         reactor.callLater(0, reactor.stop)
>         reactor.run()
>
> # ... then our handler will be called before threading's.
> atexit.register(runAndStop)
> #---------------
>
> I'm not sure if this is a problem in python, in twisted's use of  
> threading, or in trial.deferredResult, though.

Almost definitely a combination of 2 and 3, with 3 being the one  
really at fault.  Trial is horribly, horribly broken by design and  
it's really just an accident that it works at all.  The expectations  
a lot of the tests have about the reactor are also broken, but that's  
mostly just a consequence of trial sucking.

-bob