Code review comment for lp:~nick-dedekind/mir/trusted_sessions

> > There's a misuse of smart pointers - shared_ptr is about "ownership" and
> this
> > needs to be a directed *acyclic* graph to correctly manage memory. Having
> the
> > parent and child both "own" each other is wrong. At least one of these smart
> > pointers should be a raw pointer.
>
> I've not checked the required semantics, but another solution that might be
> evaluated is to use weak_ptr.

Would have liked to use weak_ptr, but it wouldn't work for setting child parents from within Session::begin_trust_session.