I am running into a issue where it looks like SQLAlchemy is not performing
the proper DB update when committing a session after modifying an object.
This happens only when all references to the updated object are lost, and I
update a mutable attribute BEFORE updating another attribute. It seems as
if MutableAttrInstanceState.__resurrect is not properly resurrecting the
object state.
I have code that basically looks like this:
def update_my_model(session, my_model_id):
my_model = session.query(MyModel, id=my_model_id).one()
my_model.mutable_attribute.mutate()
my_model.normal_attribute = 42
return my_model
session = self.logic.session_maker()
update_my_model(session, my_model_id)
session.commit()
The above code does issues the SQL to update mutable_attribute, but not
normal_attribute. Everything works if I move the mutable_attribute change
to after the normal_attribute change, remove it completely, or assign the
return value of the update_my_model call to a variable.
I have been able to determine that in that case that fails (and only in that
case) MutableAttrInstanceState._cleanup is being called as
update_my_modelreturns. However, during the
session.commit(), the call to self.manager.new_instance(state=self) in
MutableAttrInstanceState.__resurrect is not returning an object that has
normal_attribute set. From what I can tell the MutableAttrInstanceState
instance should know about the update to normal_attribute (
InstanceState.modified_event is being called when it is set). But I'm not
sure of the inner-workings of MutableAttrInstanceState,so I haven't been
able to confirm this.
My mutable_attribute is rather complex, so it is entirely possible that it
is behaving badly in some why. However, this seems like a strange failure
mode for an issue with that attribute? Anyone have ideas on what is going
on here, or what my next steps should be to track it down? If any
information I have not provided would be helpful, please let me know.
Thanks for any help!
-Lenza
--
You received this message because you are subscribed to the Google Groups
"sqlalchemy" group.
To post to this group, send email to sqlalch...@googlegroups.com.
To unsubscribe from this group, send email to
sqlalchemy+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/sqlalchemy?hl=en.
