The establisher can now contribute to the open-op success reply — the
establisher → opener direction amendment 2 left empty. First consumer:
alktunnels ADR-008's bind-first listen establisher, whose observed
OS-chosen bound address rides the reply as an additive `bound` field
(the SOCKS5 BIND reply#1 BND.ADDR fidelity ask).
- Establishment gains reply_fields (private, builder-constructed):
with_reply_field / with_reply_fields / reply_fields. The map shape
generalizes beyond `bound` without a fourth amendment; the
#[non_exhaustive] carrier (amendment 2) makes the extension additive
— no construction-site break.
- run_open_wrapper merges contributed fields into the success output
after reserving `channel_id`. The key is wrapper-owned: an
establisher supplying it fails the open loudly
(channel:open_failed, reason handler_error, message naming the
reserved key), tearing the just-allocated channel down — never
shadowing. Absent fields leave the reply byte-identical to the
pre-amendment shape (asserted exactly).
- ChannelClient::open_channel_with_reply returns
(channel_id, reply, send, recv) — the full success output — so
consumers read `bound` first-class; open_channel delegates and
discards the fields, signature unchanged.
Tests (all gates from the review + plan):
- projection produces { channel_id, bound } on the wire; no-fields
replies are byte-identical (establisher and no-establisher shapes)
- reserved-key establisher fails with reason handler_error; channel
torn down, ledger decremented, pump handler never spawned
- registry-level register_openable_with_establisher projects fields
- e2e over a real channels connection: bound reaches
open_channel_with_reply; open_channel unchanged against the same
accept side
- existing establishment tests (establisher-success round-trip,
plan-flow, no-establisher compat) pass unchanged
Docs: ADR-049 amendment 3 (projection, reservation, read path,
compatibility posture, door type).
Verification: cargo test 637 passed; clippy -D warnings clean;
cargo fmt --check clean; cargo doc --no-deps clean.
glm-5.3-flash
82ddddf986