The 14-to-15 state migration was released in urbit-os-v2.142
so we add a new ames-state-16 to account for the removal of
.num-live from $pump-metrics.
This also adds several `$+` shorthand type name for better
prettyprinting in nest-fails situations, all related to the types in
$ames-state.
(note: ames states 14 and 15 are the same, ane tha migration
just re-retrieved our own %rift—first introduced in state-12-to-13)
The guest identities (#6561) and EAuth (#6598) features will both be
released as part of Zuse 412K, so their +load logic can be collapsed
into a single step.
Keeping a queue of nonces to match the outgoing %pleas we send lets us
recover the nonce for the %done we receive in response. This is
important in the nack case, where we may want to eagerly serve the HTTP
client an error page response, instead of waiting for the timeout timer
to fire.
We probably want something slightly fancier, like a banner or something,
that also shows up on the login page (and perhaps other "system" pages),
but for now this should suffice.
Instead of doing formal network traffic on the host-side whenever a
login attempt gets initiated, we now do it no earlier than when we're on
the client-side. This has the important property that network traffic
can only be initiated by authenticated HTTP requests. The previous
implementation, where hosts sent pleas when an unauthenticated HTTP
client said then wanted to log in, was vulnerable to abuse.
So now, formally, the eauth flow starts at the client's confirmation
screen. There is an optional step preceding this, where an attempt is
started on the host (and data is still stored for this), but to get the
redirect target, the host uses remote scry to get the eauth URL out of
the client ship.
Hosts now also give attempt-specific return URLs, useful in case they
are accessible (or even serving different content) from different
hostnames.
