Re: Preventing non-superusers from altering session authorization

>> That might be a good change? If the original authenticated role ID no
>> longer exists then we may want to return an error when trying to set
>> your session authorization to that role.
>
> I was curious why we don't block DROP ROLE if there are active sessions for
> the role or terminate any such sessions as part of the command, and I found
> this discussion from 2016:
>
>        https://postgr.es/m/flat/56E87CD8.60007%40ohmu.fi

Ah, that makes sense that we don't prevent DROP ROLE on active roles.
Though, we do error when you try and set your role or session
authorization to a dropped role. So erroring on RESET SESSION
AUTHORIZATION when the original role is dropped makes it consistent
with SET SESSION AUTHORIZATION TO <dropped-original-role>. On the other
hand it makes it inconsistent with RESET ROLE, which does not error on
a dropped role.

- Joe Koshakow