[Zope3-dev] lazy object unregistration in object hub

[Garrett Smith]

A while back I added support for lazily (or implicitly) unregistering 
missing objects from the object hub. I think this is bad and should be 
removed:

- It's generally a bad thing to modify a structure on read operations 
(unexpected behavior)

- Registered object iteration requires that the underlying structure not 
be modified during iteration -- in some cases it will be with the 
current approach.

- An object may not actually be 'missing' -- there may be a problem with 
traversal that prevents the hub from accessing it via its path.

- Magically unregistering objects hides bugs.

I'm holding off on a commit that:

- Removes this implicit unregistration

- Adds UI support for viewing all of the registered objects, 
highlighting those that are 'missing' -- admins/managers still have the 
ability to unregister 'missing' objects, but do so explicitly via a 
button click

Any objections to these changes?

  -- Garrett