[Zope-CMF] ConnectionStateErrors and PersistentComponent in CMF 2.1 b1 on Zope 2.10.3

[Arnar Lundesgaard]

The 3. May. 2007 kl. 13.42, Arnar Lundesgaard wrote:
> Hi, I'm developing a site on CMF 2.1b1 on Zope 2.10.3 and somehow  
> I'm triggering ConnectionStateErrors.
>
> I'm not yet as familiar with the Zope 3 machinery as I would like,  
> but it seems that when certain requests are being closed the event  
> subsystem tries to load the sitemanager that contains references to  
> persistent objects (the portal_* tools mostly) and do some cleanup.
>
> This raises a ConnectionStateError as the Connection has alread  
> been closed. It doesn't happen all the time, and it appears more  
> often when the user is Anonymous.
>
> It seems to be trying to load data on the _components attribute on  
> the portal object as a Site after the connection has been closed.
>
> Anyone know what could be causing this?


Some more digging revealed that switching two lines in  
ZPublisher.BaseRequest.BaseRequest.close ensures that the connection  
is closed _after_ the eventsystem finishes cleaning up.

# Current version
def close(self):
     self.other.clear()
     self._held = None
     notify(EndRequestEvent(None, self))

# Patched version
def close(self):
     self.other.clear()
     notify(EndRequestEvent(None, self))
     self._held = None


self._hold seems to "hold" a ZApplicationWrapper from App/ 
ZApplication.py and calls App.ZApplication.Cleanup.__del__ when the  
last reference is removed. Cleanup.__del__ contains:
     self._jar.close()


I have no idea what sort of ill effects this change might have, but  
it solved the problem I was seeing with persistent components and I  
haven't ѕeen any new problems yet. I'll be monkeypatching this until  
somebody tells me it is a bad idea. :-)

The notify call was added 1.5 year ago:
   <http://svn.zope.org/Zope/trunk/lib/python/ZPublisher/ 
BaseRequest.py?rev=30278&r1=39848&r2=30278>


  Arnar Lundesgaard  |  Consultant
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http://www.bouvet.no  |  arnar.lundesgaard at bouvet.no