[ZODB-Dev] know the state of an object

[Tim Peters]

 [Victor Safronovich]
>>>       invalidate

[Dieter Maurer]
>> I think, this is not easily available, but
>> "obj._p_changed = None" might work

[Victor]
>     What about obj._p_invalidate()?

I don't think _p_invalidate() existed before ZODB 3.3.

At and after 3.3,

    obj._p_invalidate()

is the same as

    del obj._p_changed

and

    obj._p_deactivate()

is the same as

    obj._p_changed = None

I wish the latter spellings could go away.

Ah, fudge.  The docs (persistent/interfaces.py) claim that _p_invalidate()
is the same as del'ing _p_changed, but it's not clear that that's always
true (the implementation of _p_invalidate does more than the implementation
of del'ing _p_changed) .  I'm not sure what the intent was.