[Zope-dev] Help: __getstate__ overriding

[Tim Peters]

[Dieter Maurer]
> I think, this is a ZODB buglet:
>
>   It should set "_p_changed = 0" before it calls "__setstate__"
>   and not afterwards...

I don't know; Jim (or Jeremy) may know the reasoning here, but I don't.

Activation currently sets the state to changed *before* calling __setstate__
too.  A comment says this is to prevent recursively calling _PyPersist_Load,
and that makes sense to me, else unbounded recursion could occur.

Given this abuse of _p_changed, and that the purpose of activating a ghost
is to transition it to the up-to-date state, making mutations to the
persistent state inside __setstate__ seems hard to accommodate.

On ZODB head, Jeremy also documented that __setstate__ can't affect the
persistent state (in persistent/interfaces.py's IPersistent).  Whether this
is deliberate design, or a consequence of the current implementation, I
can't say.