---
id: review-002-con18-wss-sweep-exit
name: Dead-connection fast-fail + bounded from_wss sweep exit (CON-18)
status: completed
depends_on: []
scope: narrow
risk: low
impact: component
level: implementation
tags: [adapters, review-002, from-wss]
---

## Description

Review 002 CON-18 [minor]. The review-001 CON-02 fix added a 1 s
pending-map sweep to `from_wss`'s drop monitor — but it never exits:
once `eof_observed` holds, the sweep branch runs `fail_all` every
second **forever** (`from_wss.rs:254-272`). Each fire-and-forget
`import()` whose peer dies leaves a spawned task + pending map + watch
receiver alive for the process lifetime (a true task/allocator leak
scaling with import count). Note the naive fix is wrong: the sweep
test proves post-EOF registrations race `fail_all` and hang without
the sweep — so exit requires making post-EOF registration fail fast
*first*.

## Acceptance Criteria

- [ ] Post-EOF (dead connection) registration fails fast: calls
      registered after the observed EOF resolve immediately with
      `CONNECTION_CLOSED` (retryable, matching the established
      mapping) instead of relying on the next sweep tick
- [ ] The sweep then exits after a bounded grace period following EOF
      (long enough that the fast-fail path is exercised; not forever)
      — no per-dead-session permanent task remains
- [ ] Re-verify the existing race tests still pass (pre-drop,
      forgotten/held drop-during-registration, post-EOF sweep —
      from_wss.rs:809-1001) and tighten assertions where the fast-fail
      makes timing deterministic
- [ ] A task-lifecycle test (or task-count assertion) proving the
      monitor ends after teardown
- [ ] `cargo test --features wss`, `cargo clippy --features wss --all-targets -- -D warnings`,
      `cargo fmt --check` pass

## References

- docs/reviews/002-post-remediation-review.md (Part B', CON-18 / CON-16-withdrawn merge note)
- src/adapters/from_wss.rs:244-273 (the monitor loop), :75 (interval), :305 (fire-and-forget import)
- tasks/adapters/review-001-ws-eof-signal.md (the WS-02/CON-02 fix this bounds)
- alkcall/docs/reviews/consumer-findings-ledger.md CF-001 (the retryability classification — keep consistent)

## Notes

Implementation shape suggestion: an `AtomicBool`/watch-dead flag on
the call connection consulted in the registration path (fail-fast)
plus a sweep-generation counter (exit after N idle sweeps post-EOF).
The alkcall-side CF-001 note matters: if/when the dead-mux write
mapping changes, the fail-fast class here should match. Keep the
WS-02 losslessness invariant intact — fast-fail is an *additional*
resolution path, not a replacement for the watch signal.

## Summary

50ms drain interval + monitor return after 8 consecutive empty post-EOF drains (~400ms grace); post-EOF registrations fail fast with retryable CONNECTION_CLOSED; fixed a busy-spin in the old select's eof branch. ADR-070 updated. No public API change.