[Zope-CMF] Re: Delete trouble

[Miles]

Philipp von Weitershausen wrote:
Martin Aspeli wrote:
Traceback (innermost last):
  Module ZPublisher.Publish, line 119, in publish
  Module ZPublisher.mapply, line 88, in mapply
  Module ZPublisher.Publish, line 42, in call_object
  Module OFS.ObjectManager, line 524, in manage_delObjects
  Module OFS.ObjectManager, line 379, in _delObject
  Module zope.event, line 23, in notify
  Module zope.component.event, line 26, in dispatch
  Module zope.component._api, line 130, in subscribers
  Module zope.component.registry, line 290, in subscribers
  Module zope.interface.adapter, line 535, in subscribers
  Module zope.component.event, line 33, in objectEventNotify
  Module zope.component._api, line 130, in subscribers
  Module zope.component.registry, line 290, in subscribers
  Module zope.interface.adapter, line 535, in subscribers
  Module OFS.subscribers, line 108, in dispatchObjectWillBeMovedEvent
  Module zope.app.container.contained, line 182, in 
dispatchToSublocations
  Module zope.component._api, line 130, in subscribers
  Module zope.component.registry, line 290, in subscribers
  Module zope.interface.adapter, line 535, in subscribers
  Module OFS.subscribers, line 108, in dispatchObjectWillBeMovedEvent
  Module zope.app.container.contained, line 182, in 
dispatchToSublocations
  Module zope.component._api, line 130, in subscribers
  Module zope.component.registry, line 290, in subscribers
  Module zope.interface.adapter, line 535, in subscribers
  Module Products.CMFCore.CMFCatalogAware, line 285, in 
dispatchToOpaqueItems
  Module zope.component._api, line 130, in subscribers
  Module zope.component.registry, line 290, in subscribers
  Module zope.interface.adapter, line 535, in subscribers
  Module Products.CMFCore.CMFCatalogAware, line 306, in 
handleOpaqueItemEvent
  Module Products.CMFUid.UniqueIdAnnotationTool, line 87, in 
manage_beforeDelete
  Module zope.component._api, line 207, in getUtility
ComponentLookupError: (<InterfaceClass 
Products.CMFUid.interfaces.IUniqueIdAnnotationManagement>, '')

The UniqueIDAnnotationTool should probably do a *query*Utility (which 
will return None in case the utility can't be found) and simply not do 
anything in such a case. The canonical way of expressing such fail-safe 
routines is therefore:

  component = query{Utility|Adapter|MultiAdapter}(...)
  if component is not None:
      ...



I think I have a patch that will sort this out.  The issue is that the 
UID annotations define a manage_beforeDelete method that is called via 
subscribers to the IOpaqueItemEvents interface, but, being "old zope", 
doesn't know whether it is being deleted or moved and does some lookups 
that are unnecessary when deleted.

Changing this so there is an event subscriber for UIDs that does not use 
manage_beforeDelete will sort the problem, as nothing will be done when 
the item is deleted.

I don't know whether there is a wider issue around BBB and the order 
that events are fired though (manage_beforeDelete looks to have had a 
'children first' approach, whereas it looks as if dispatchToSublocations 
has a 'children last' approach)

Miles

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