Extract the deferred AlknetClient as a new crate alknet-client — the
client-side analogue of AlknetEndpoint. Three dial methods (QUIC +
TCP+TLS via TlsClientConfig, iroh via key) produce a Connection for
CallClient::spawn_dispatch / ChannelClient::from_connection to consume.
The deferral collapsed because ADR-086 gave the native endpoint type
three dial shapes within one endpoint type, ADR-087 broke the circular
hedge, and ADR-083 gave the server-side shape to mirror by symmetry.
Names the three concept layers that were tangled throughout the initial
development (deployment role / establishment side / ALPN-level category)
so the fix is legible. Names alknet/register as a dialable entry-point
ALPN (native registration, parallel to HTTP registration in OQ-58); its
wire protocol is deferred to OQ-66 (blocked on OQ-58's token model).
Cross-references updated across 11 existing docs (README, overview,
open-questions, OQ-55, tls, hub, core, channels README/overview/
channel-client, call client-and-adapters) to reflect OQ-55 resolved and
the new alknet-client crate. Architecture review passed (2 critical, 7
warnings — all addressed).
The channels protocol is transport-agnostic by design (ADR-071 substrate
modes; ADR-065 unwound the server-side QUIC-welding via
Connection::from_stream/from_bidi). ADR-080 had welded the client-side
one-way-door API to QUIC and masked it as a deferral ('QUIC-only
initially', 'can be generalized later') — anti-patterns #8/#9/#11
(door-type-as-deferral + resolved-with-escape-hatch). 'Can be
generalized later' meant 'can be rewritten later' — the expensive
reversal the one-way-door classification exists to prevent.
Fix: split the constructor surface.
- from_connection(connection: Connection) — transport-agnostic primary,
one-way door. Mirrors server-side ChannelsAdapter::handle(Connection)
and the existing CallClient::spawn_dispatch pattern.
- connect_quic(addr, credentials) — QUIC convenience, two-way door,
additive. Future connect_tcp_tls / connect_webtransport join it
without touching the one-way-door surface.
OQ-55 reframed: the deferred thing is the shared dial+TLS seam
(AlknetClient), not a QUIC-welded client API. The client take-over APIs
(CallClient::spawn_dispatch, ChannelClient::from_connection) are
transport-agnostic and decided; only the shared dial across transports
is blocked on a second transport's dial existing.
Files:
- decisions/080-channelclient.md: amendment section, Decision code
block, Transport-agnostic by construction (replaces QUIC-only
initially), Consequences, Door type, subscribe_resources added to
Decision block (was referenced by Door type but missing)
- crates/channels/channel-client.md: from_connection primary API,
Transport-agnostic by construction section, OQ-55 relationship
- crates/channels/overview.md, crates/channels/README.md,
crates/core/README.md, README.md, open-questions.md,
questions/055-...md: cross-reference summaries aligned
Two refinements from the review:
1. Control stream_types (3/4/5) carry ALPN-specific payloads, not
JSON. The channels layer is blind to what control stream_types carry —
it reassembles bytes and delivers them to the handler. TTY happens to
use JSON for its control channel because its control messages map
cleanly to JSON; another ALPN might use a binary format. The channels
layer does not mandate JSON on control stream_types, the same way it
doesn't mandate a format for data stream_types. This prevents the
TTY/PTY JSON constraint from becoming a binding constraint on all
future channel types. (ADR-071, channels-wire.md)
2. Hub and worker are consumers of channels, not sub-crates. The existing
alknet-hub crate IS the channels hub — it depends on channels-call and
uses channels as its substrate, with the relay logic (ADR-079) living
in alknet-hub. A worker is any crate that uses ChannelClient to dial.
There are no channels-hub or channels-worker sub-crates. The dependency
direction is: alknet-hub → channels-call → channels-core → alknet-core;
worker → channels-call → channels-core → alknet-core. The channels
crate has no dependency on alknet-hub or any worker crate. (ADR-081,
overview.md)
Three simplifications to the channels spec, all flowing from the review:
1. Substrate simplification (ADR-071 revised): the 9-byte chunk header is
used in ALL substrates — in-line (TCP+TLS, WebTransport), native (QUIC
bidi streams), and multi-connection. The ChannelsAdapter reads headers
off every bidi stream it accepts; the transport's native multiplexing
is a performance optimization (independent flow-control windows), not a
protocol change. One wire format, one code path, one handler experience.
The channel_id in the header is the correlation key across substrates.
2. Stream_type decomposition (ADR-071 revised): every stream_type is
unidirectional. Bidirectionality is two stream_types (write + read), not
one 'bidirectional' stream_type. Grouped in threes: 0/1/2 = data
write/read/err, 3/4/5 = control write/read/err, % 3 formula. This
resolves the TTY control channel's 'not actually bidirectional' flaw —
control is now 3 (write, client→server) + 4 (read, server→client), each
with its own reassembly buffer and EOF. Channel 0 uses [0,1] (call frames
bidirectional via 0=in, 1=out). TTY uses [0,1,2,3,4]. ADR-072, 073, 074,
077 updated for the new stream_type assignments.
3. Sub-crate decomposition (ADR-081 new): channels-core (pure multiplexer —
wire format, demux/mux, ChannelBidiStreamSource, ChannelManager; depends
on alknet-core only, no call dependency, ALPN-blind) / channels-call
(channel 0 pre-negotiation + lifecycle op registrations; depends on
channels-core + alknet-call) / channels-hub (relay) / channels-worker
(ChannelClient). Isolates the call-protocol coupling from the pure
multiplexer so the dependency graph is honest.
ADR-077 (TTY inside channels) updated: TTY now uses 5 sub-streams [0,1,2,3,4]
with control properly bidirectional via 3/4; amends ADR-052's stream_type
assignments for direct mode too (direct alknet/tty now uses 0-4, not 0-3).
Spec docs updated: channels-wire, channels-connection, channels-adapter,
channel-operations, overview, README.
glm-5.2