# M2a task 14: pass the upstream's close on to the client (review follow-up)

**Branch:** `m2a` (run `git switch m2a`; `git status --short` must be empty, otherwise stop)
**Commit subject:** `Close the client side when the upstream closes, in inferproxy`

## Goal

The M2a review found that `inferproxy` only closes towards the client after the client has stopped
sending. `loopd`'s HTTP client never stops sending on its own: it keeps its side open until it
drops the connection. So when `llama-server` closes, or dies in the middle of an answer, the client
is not told; it sits until its own liveness timeout and reports `Stalled` instead of
`StreamClosedEarly`, thirty seconds late. A body that runs to the close would hang the same way.

Task 02, rule 3, said: "When the server stops sending, the exchange is over: close both." The
current code waits for both copy threads to finish instead. This was partly the plan's fault: every
test client in `forward.rs` half-closed after sending, so the gap could not show. The new test
sends without half-closing.

## Files

- Copy (replacing the old one): `crates/inferproxy/tests/forward.rs`
- Modify: `crates/inferproxy/src/lib.rs`, `docs/implementer-log.md`

## Required behaviour

- When the server-to-client copy ends, for any reason, shut down the client connection (both
  directions) and the server connection, so that the client's read returns 0 at once and the
  client-to-server copy thread ends. Do this **after** releasing the open-connection place, as
  rule 4 of task 02 requires.
- Everything else from task 02 still holds, including the half-close when the client stops
  sending first.

## Steps

- [ ] **1. Copy.** `git switch m2a`, then
  `cp docs/plans/M2a/files/crates/inferproxy/tests/forward.rs crates/inferproxy/tests/`
- [ ] **2. See it fail.** `cargo test -p inferproxy --test forward`. Expected: 1 of 7 fails,
  `the_upstreams_close_reaches_a_client_that_is_still_sending`, with a timeout.
- [ ] **3. Fix `lib.rs`.** Run `cargo fmt --all`.
- [ ] **4. See it pass.** `cargo test -p inferproxy --test forward`, ten times in a row. Expected:
  `7 passed` every time.
- [ ] **5. Run the gate.** `make gate`. Expected last line: `gate: ok`.
- [ ] **6. Log and commit.** `git add crates/inferproxy docs/implementer-log.md && git commit`

## Done when

- `cargo test -p inferproxy --test forward` reports 7 passed, ten runs in a row; `make gate` prints
  `gate: ok`; `cmp crates/inferproxy/tests/forward.rs docs/plans/M2a/files/crates/inferproxy/tests/forward.rs` prints nothing.

## Stop and report if

- Passing the new test breaks `forwards_both_ways_and_passes_the_half_close_on`.