On Mar 29, 2012, at 6:48 AM, lars van gemerden wrote:
> I think I have an odd case of the first possibility you mentioned:
>
> I am generating XML from SAclass objects opdating these objects from
> XML. To detect cyclic references and double objects, I maintain a
> registry of objects based on id() (reg[str(id(obj))] = obj). The id is
> stored as the attribute "ID" in the XML tag. When updating the objects
> I first look them up in the registry obj = reg[etree.get("ID")] and
> update them afterwards. I do this as well with relationships/
> InstrumentedLists (but not with database fields like Integer).
>
> What I noticed was that InstrumentedList changes id() after a commit
> (with a = Address(), Address.persons = relationship(...) ):
>
> print id(a), id(a.persons), id(a.persons[0])
> session.commit()
> print id(a), id(a.persons), id(a.persons[0])
>
> gives:
>
> 47148168 47174264 47114112
> 47148168 47175784 47114112 (the middle id has changed)
>
> So I assume that after a commit a new InstrumentedList is created.
that's only because commit() expires all attributes and collections, so you get
a new one on next access.
>
> - Could it be conceivable that is causes the warning mentioned
> above(an old version of the InstrumentedList being updated with an
> valid SAclass object)?
the InstrumentedList itself is not something that's tracked by the session,
it's only a container stuck on the parent object. Somehow a.persons[0] or
some other element is being expunged from the session, or is not being placed
inside to start with.
As always, if you could demonstrate the warning with a small test case I can
quickly determine what the exact cause is.
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