dx EventBasic swallows exception

[zopyx]

The 'start' property implementation of EventBasics swallows somehow exceptions.

Accessing the start property fails internally

(Pdb) self._prepare_dt_get(self.context.start)
*** AttributeError: timezone

self.context.start is cleary a datetime instance with a timezone

(Pdb) print self.context.start.tzinfo
<plone.app.event.dx.behaviors.FakeZone object at 0x9327590>

The start property has been created as recommended in the other ticket through the behavior interface with pytz.timezone('CET').

Why is this exception swallowed and obviously somewhere transformed into None instead of dealing with the error properly? The call stack is:

/home/ajung/.buildout/eggs/zope.tal-3.5.2-py2.7.egg/zope/tal/talinterpreter.py(518)do_optTag()
-> return self.no_tag(start, program)
/home/ajung/.buildout/eggs/zope.tal-3.5.2-py2.7.egg/zope/tal/talinterpreter.py(513)no_tag()
-> self.interpret(program)
/home/ajung/.buildout/eggs/zope.tal-3.5.2-py2.7.egg/zope/tal/talinterpreter.py(343)interpret()
-> handlers[opcode](self, args)
/home/ajung/.buildout/eggs/zope.tal-3.5.2-py2.7.egg/zope/tal/talinterpreter.py(620)do_insertText_tal()
-> text = self.engine.evaluateText(stuff[0])
/home/ajung/.buildout/eggs/Zope2-2.13.21-py2.7.egg/Products/PageTemplates/Expressions.py(225)evaluateText()
-> text = self.evaluate(expr)
/home/ajung/.buildout/eggs/zope.tales-3.5.3-py2.7.egg/zope/tales/tales.py(696)evaluate()
-> return expression(self)
/home/ajung/.buildout/eggs/zope.tales-3.5.3-py2.7.egg/zope/tales/expressions.py(217)call()
-> return self._eval(econtext)
/home/ajung/.buildout/eggs/Zope2-2.13.21-py2.7.egg/Products/PageTemplates/Expressions.py(147)_eval()
-> ob = self._subexprs-1
/home/ajung/.buildout/eggs/zope.tales-3.5.3-py2.7.egg/zope/tales/expressions.py(124)_eval()
-> ob = self._traverser(ob, element, econtext)
/home/ajung/.buildout/eggs/Zope2-2.13.21-py2.7.egg/Products/PageTemplates/Expressions.py(97)trustedBoboAwareZopeTraverse()
-> request=request)
/home/ajung/.buildout/eggs/zope.traversing-3.13.2-py2.7.egg/zope/traversing/adapters.py(136)traversePathElement()
-> return traversable.traverse(nm, further_path)
/home/ajung/.buildout/eggs/zope.traversing-3.13.2-py2.7.egg/zope/traversing/adapters.py(42)traverse()
-> attr = getattr(subject, name, _marker)
/home/ajung/.buildout/eggs/plone.app.event-1.2-py2.7.egg/plone/app/event/dx/behaviors.py(611)getattr()
-> return safe_unicode(getattr(behavior, name, None))

/home/ajung/.buildout/eggs/plone.app.event-1.2-py2.7.egg/plone/app/event/dx/behaviors.py(347)start()
-> return None