Add assertions for the redirect URL in the unit test for the stateful
authentication flow Callback() method. Remove a commented-out line of
debug logging.
The identity manager expects to be able to read session ID and user ID
from any deleted databroker session records. The session.Delete()
wrapper method is not compatible with this expectation, as it calls
Put() with a record containing an empty session. The stateful
authentication flow currently calls session.Delete() from its
RevokeSession() method.
The result is that the identity manager will not correctly track
sessions deleted by the the stateful authentication flow, and will still
try to use them during session refresh and user info refresh.
Instead, let's change the stateful authentication flow RevokeSession()
method to perform deletions in a way that is compatible with the current
identity manager code. That is, include the existing session data in the
Put() call to delete the revoked session.
Add a new Stateful type implementing the stateful authentication flow
from Pomerium v0.20 and earlier.
This consists mainly of logic from authenticate/handlers.go prior to
commits 57217af and 539fd51.
One significant change is to set the default IdP ID when an IdP ID is
not provided in the request URL (e.g. when signing in directly at the
authenticate service domain). Otherwise, if session state is stored with
an empty IdP ID, it won't be valid for any route.
