handleUidAnnotationEvent from Products.CMFUID throws AttributeError

Posted on April 20, 2012
Tags: ,
I stumbled over a weird error during a package setup, which turned out a PEBCAC error. The full traceback: 

[...]
File "/home/roman/.buildout/eggs/zope.interface-3.6.3-py2.6-linux-x86_64.egg/zope/interface/adapter.py", line 583, in subscribers
    subscription(*objects)
File "/home/roman/.buildout/eggs/Products.CMFUid-2.2.1-py2.6.egg/Products/CMFUid/UniqueIdAnnotationTool.py", line 86, in handleUidAnnotationEvent
    uid_handler.unregister(ob)
AttributeError: 'NoneType' object has no attribute 'unregister'
I went throught my whole code and type setup unable to find the mistake I’ve made unless I saw the problem. I imported a configuration module for an ArcheTypes content type declaration from a separate package which was not declared in the setup.py of my new package, e.g.: 

$ cat my.package.event.py
from separate.package.config import PROJECTNAME
from plone.directives.form import Schema

class IMyType(Schema): ...

If you stumble over this error, make sure your imports are sane.