Throw a when two objects represent the same document in a session

[sebastienros]

No description provided.

[sebastienros]

With the recent changes on identity map, when SaveChangesAsync() is invoked to commit the transaction we clear the IM such that the next queries get refreshed data from the db.

With that change, if we kept a previously loaded object (and potentially modified) but also did a query that was loading the same identity, we could get two objects with different states. This will throw a meaningful exception now.

This happens in OC where the identity stores call SaveChangesAsync after each operation, committing the transaction, where they should do nothing and let auto-flush "flush" the db (without committing the transaction and clearing the IM), or call FlushAsync(). So in a parallel PR I will remove these calls and replaces them with FlushAsync.

[MikeAlhayek]

How would this code fix the problem we noticed today? Wouldn't this throw a different spin exception but still fails?

[sebastienros]

Yes, this is not fixing the problem "in OC", there is a PR in OC for that. It's just showing a better message such that if someone missuses yessql they will know.