---
id: fork-port-connection-watcher
name: Fork port — connection architecture + watcher machinery
status: pending
depends_on: [fork-substrate-scaffold]
scope: broad
risk: medium
impact: component
level: implementation
tags: [wave-2, substrate]
---

## Description

Port the connection/watcher half of honker-core into
`alkstore-sqlite/src/substrate/` — the machinery the quality read
verified clean and ADR-011 §scope inherits near-verbatim. Source:
`/workspace/honker/honker-core/src/` @ `f4e53c6` (`lib.rs` ~4k lines,
`shm_watcher.rs`, `kernel_watcher.rs`).

**Port (the kept half, ADR-011 / quality-read §6):** the PRAGMA/WAL
open posture + `set_journal_mode_wal` retry logic; `Writer`; `Readers`;
the polling watcher + `SharedUpdateWatcher` + `WatcherDeathGuard` +
`stat_identity` dead-man's switch; the `in_savepoint` /
`UnwindUndo` mutation-discipline machinery; the REAL-coercion arg
helpers; the notify scalar + notifications table; stream functions;
lock functions.

**Port deltas (ADR-012 §4 — the only deliberate behavior changes):**

- W-1: bounded reconnect backoff in the watcher loop (no ~1000
  open-attempts/sec on a vanished db file).
- W-2: watcher spawn becomes fallible; callers (the engine, wave 3)
  surface the failure at open time.
- Dead-man's switch: the db-file-identity-change panic is replaced by
  a deliberate watcher-fatal death (log the precise diagnostic, exit
  through the ordinary death path); `WatcherDeathGuard`'s
  death-closes-subscribers behavior unchanged.

**Drops (do not port):** `cron.rs`; the `kernel-watcher` /
`shm-fast-path` experimental watcher backends and their optional deps
(`notify`, `memmap2`, `libc`); the rate-limit and result tables; the
superseded queue functions (the queue half is re-derived in a separate
task).

**Table naming:** `_honker_*` → `__alkstore_*` across the ported
storage surface (ADR-011; ADR-010 §8 authorization). No online
migration machinery — fresh bootstrap only (ADR-012 §5).

**Fidelity posture (ADR-012 §3):** keep upstream's module structure and
internal function names for the kept half, including lineage tokens
(`Writer`, `run_poll_loop`, `in_savepoint`). Renames confined to the
table family and the hygiene deltas. The port is mechanical where
possible — the diff against the lineage must stay reviewable.

**Discipline deltas (family standard, ADR-012 §4):** no comments in
code (doc comments on the substrate's internal public surface fine),
no panics in library code (the dead-man's-switch delta is the big
one), no `unwrap()`/`expect()` outside tests. The substrate stays sync
— no tokio, no asyncification.

**Bootstrap re-keying (ADR-012 §5):** the fork owns the bootstrap;
append-column migrations stay; the duplicate-column race swallow is
re-keyed to `pragma_table_info` verification (present ⇒ benign race,
absent ⇒ propagate) — upstream's error-string matching is not
inherited.

**Tests (the floor, ADR-011):** inherit honker-core's suites for the
ported machinery — PRAGMA/WAL, watcher lifecycle + failure handling,
savepoint + multiprocess pressure — adapted to the new table names and
the three port deltas. These run as engine-crate tests (the substrate
is not separately testable through a public seam).

## Acceptance Criteria

- [ ] Kept machinery ported with upstream names/structure preserved;
      diff vs. lineage reviewable (the wave-2 review checks this)
- [ ] Three watcher deltas applied; dead-man's switch exits without
      panicking; `WatcherDeathGuard` still closes all subscribers
- [ ] Dropped machinery absent (no cron, no experimental watchers, no
      rate-limit/result tables, no superseded queue functions)
- [ ] Table family is `__alkstore_*`; bootstrap fresh-only; race
      swallow re-keyed to `pragma_table_info`
- [ ] Inherited test suites green (adapted); watcher-death-closes-
      subscribers test present
- [ ] Substrate is sync (no tokio imports); no panics/`unwrap()` in
      library code; clippy `-D warnings`, fmt clean

## References

- docs/architecture/decisions/011-sqlite-substrate-fork.md (scope register)
- docs/architecture/decisions/012-forked-substrate-design.md §3–§5
- docs/research/quality-read-honker-core.md §6 (the fork scope), §2 (watcher verdict)
- /workspace/honker @ f4e53c6 (the lineage)

## Notes

> To be filled by implementation agent

## Summary

> To be filled on completion