[Zope-CMF] Re: Weird error

[Laurence Rowe]

.implementedBy is for classes (is this interface implemented by 
instances of a class), .providedBy is for instances (is this interface 
provided by this object).

The only way I can think that you may trigger this error during 
unpickling is if you have somehow managed to get an __implemented__ 
attribute on the object itself. Not sure how you would manage that.

Probably the best bet is to truncate your filestorage to a transaction 
before the change was persisted. Otherwise, you'll need to provide some 
more information, i.e. the pickle and the class definition. PDBDebugMode 
may be of help.

Laurence


Charlie Clark wrote:
> Hi,
> 
> whilst trying out some Zope 3 stuff (implementedBy, providedBy) I 
> managed to screw up some portal objects but I'm not quite sure how and 
> I've no idea how to fix them.
> 
> I effectively did something like:
> 
> for obj in folder.contentValues:
>     if IMyInterface.implementedBy(obj):
>         do_something_with_object()
> 
> If I understand things correctly this should not affect the objects 
> themselves at all but it does and leads to the following error when I 
> subsequently try and access them.
> 
> Traceback (most recent call last):
>   File "/opt/Zope-2.10/lib/python/ZODB/Connection.py", line 761, in 
> setstate
>     self._setstate(obj)
>   File "/opt/Zope-2.10/lib/python/ZODB/Connection.py", line 819, in 
> _setstate
>     self._reader.setGhostState(obj, p)
>   File "/opt/Zope-2.10/lib/python/ZODB/serialize.py", line 604, in 
> setGhostState
>     state = self.getState(pickle)
>   File "/opt/Zope-2.10/lib/python/ZODB/serialize.py", line 597, in getState
>     return unpickler.load()
>   File "/opt/Zope-2.10/lib/python/zope/interface/declarations.py", line 
> 352, in implementedByFallback
>     raise TypeError("ImplementedBy called for non-factory", cls)
> TypeError: (<exceptions.TypeError instance at 0x348cc88>, <built-in 
> function implementedBy>, (<Container at >,))
> 
> Any idea how I can fix this?
> 
> It turns out that I need to use .providedBy() rather than 
> .implementedBy() although I'm not too clear of the distinction.
> 
> Charlie
> -- 
> Charlie Clark
> Helmholtzstr. 20
> Düsseldorf
> D- 40215
> Tel: +49-211-938-5360
> GSM: +49-178-782-6226
> 
> 
> 
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