We've had a concept of "persistence by reachability" for a long time. When a
relationship is established between 2 objects, if one of them is in an
ObjectContext and another one is not, we'd automatically register the transient
object using the context of the persistent objects.
Now consider a different case... If a relationship is established between 2
objects that are both registered, but in 2 different contexts, the current
behavior is to throw an exception. I am trying to decide whether it is wise to
resolve cross-context conflict quietly instead, replacing the target object
with a copy local to the source ObjectContext by calling
ObjectContext.localObject(..). This should remove a fair amount of boilerplate
if you are using multiple contexts throughout the app as I do.
It doesn't come free though. The the code then becomes more obscure and
error-prone. E.g.:
A a = ; // in c1
B b = ; // in c2
a.setB(b); // equivalent to a.setB(c1.localObject(b))
// i.e. we are attaching a different copy of B now.
b.setProp("newValue"); // we may not realize that we are changing the wrong
copy...
c1.commitChanges(); // "b" changes are not committed. oops...
I am leaning towards leaving things as they are, but maybe someone has better
ideas on how to keep it both convenient and robust at the same time :)
Thanks,
Andrus
