[Zope3-Users] Own packages corrupts ZODB

[Florian Lindner]

Hello,
I've created a new package which causes a system error very time the ZMI 
folder listing of the folder which contains an instance of the object is 
listed:

The traceback is:

Traceback (innermost last):
   Module zope.publisher.publish, line 138, in publish
     result = publication.callObject(request, object)
   Module zope.app.publication.zopepublication, line 153, in callObject
     return mapply(ob, request.getPositionalArguments(), request)
   Module zope.publisher.publish, line 113, in mapply
     return debug_call(object, args)
    - __traceback_info__: <bound method 
ReadContainerXmlObjectView.singleBranchTree of 
<zope.app.publisher.browser.viewmeta.ReadContainerXmlObjectView object 
at 0x00E2AEB0>>
   Module zope.publisher.publish, line 119, in debug_call
     return object(*args)
   Module zope.app.rotterdam.xmlobject, line 133, in singleBranchTree
     name, len(subItem), iconUrl))
ForbiddenAttribute: ('__len__', <CS.centershock.centershock.Centershock 
object at 0x01212EF0>)


I have no idea what can cause this.
The only special thing is that the interface has no members:


from zope.interface import Interface
from zope.app.container.interfaces import IContained

class ICentershock(IContained):
     """Main component"""

     def __setitem__(name, object):
         """Add a ICentershock object."""


The registration:



<configure xmlns="http://namespaces.zope.org/zope">
	<include package=".browser" />
	
	<interface interface=".interfaces.ICentershock" 
type="zope.app.content.interfaces.IContentType" />
	<content class=".centershock.Centershock">
		<implements 
interface="zope.app.annotation.interfaces.IAttributeAnnotatable" />
		<implements interface="zope.app.container.interfaces.IContentContainer" />
		<factory description="centershock.net"/>
		<require permission="zope.Public" interface=".interfaces.ICentershock" />
		<require permission="zope.Public" set_schema=".interfaces.ICentershock" />
	</content>
	
</configure>

the package browser registration:

<configure xmlns="http://namespaces.zope.org/browser">
	<addMenuItem
		class="..centershock.Centershock"
		title="centershock.net"
		description="A centershock.net object"
		permission="zope.ManageContent"
	/>

	<editform
		schema="..interfaces.ICentershock"
		label="Change centershock.net information"
		name="edit.html"
		permission="zope.ManageContent"
		menu="zmi_views" title="Edit"
	/>

	<containerViews
		for="..interfaces.ICentershock"
		index="zope.Public"
		contents="zope.Public"
		add="zope.ManageContent"
	/>
</configure>


what is wrong with that?

Thanks,

Florian