alkstore/docs/architecture/decisions/005-dependency-ownership.md

ADR-005: Dependency ownership — published libraries by default, named fork triggers

Status

Accepted (posture); fork triggers are live assessments tracked in OQ-06

Context

The crate's reactive machinery sits on third-party work: honker (SQLite side) and, conceptually, pgboss-rs (Postgres queue family). Neither is adopted-by-adjacency — per guiding principle 3, ownership of each subsystem is a deliberate per-question decision. The workspace precedent is the targeted fork (alksocks' fast-socks5 extraction), but a fork is expensive (especially when the forked code is sync and the family standard is tokio — a fork of honker-rs is already a serious port).

Two POCs (2026-10-04) measured the relevant postures per subsystem; each carries its own record. This ADR fixes the default calculus and the per-subsystem resolutions so Phase 1 design work starts from stable ground.

Decision

Default posture: consume published libraries. Fork or vendor only when a named trigger fires. Per subsystem:

Subsystem	Posture	Notes
honker-core (SQLite engine machinery)	published library, honker-core = 0.5 — trigger fired 2026-10-05: forked per [ADR-011]	Fork trigger: the Phase 1 quality read of the watcher/transactional core finds a defect, OR a needed change upstream won't take. OQ-06 tracked the read; the read fired the trigger (published 0.5.0 carries the unreleased-fix-train defect class + ADR-010's queue depth requires engine-owned queue SQL in any posture).
rusqlite	published, riding honker-core's pin	Pin movement is honker-core's; we ride it ([ADR-003]).
tokio-postgres + deadpool-postgres	published library, as-is	Clean, zero conflicts, actively maintained (POC #2).
postgres-notify	not adopted (derive-not-adopt)	Lazy reconnect, connect_script skipped at initial connect, unquoted-identifier LISTENs, single maintainer. Hand-rolled forwarder instead ([ADR-004]). Fallback if upstream improves materially.
pg-boss queue machinery (pgboss-rs / node pg-boss)	re-derived on our driver; schema family as design reference only	pgboss-rs brings sqlx (second driver per binary) and has no LISTEN/NOTIFY (verified); the push half is ours either way, so queue-machinery reuse value is the honest comparison point and it loses on that arithmetic. Semantics depth: [queues.md], OQ-05.
honker-rs interface shape	design reference, not a dependency	Sync-only (no tokio); the surface is prior art for contract pinning ([ADR-006]), not code to ship.

If any fork fires, forking is normal work we own (license/provenance recorded per AGENTS.md §3 at adoption time) — it is not an exception to this posture.

Consequences

Positive

• Zero vendored code in the tree by default; upgrades are cargo update work, not patch-management work. (Exception now live: the [ADR-011] fork is a vendored family crate — the named trigger, not a posture change.)
• The fork triggers are concrete and named before the quality read, so the read produces a decision, not a debate.
• Per-subsystem votes are recorded with evidence, so no future discussion re-litigates from scratch.

Negative

• honker-core 0.5 remains alpha-quality software per its own README in the link graph; the quality read (OQ-06) is the mitigation gate. (Resolved 2026-10-05: the read fired the trigger — [ADR-011]. This row's negative consequence is retired with it; the "zero vendored code" positive consequence now carries ADR-011's named exception.)
• The pg queue machinery is written by us — the pg-boss family's battle-tested edge cases must be re-earned by design + tests ([queues.md]).

References

• docs/research/poc-sqlite-posture-findings.md §"What feeds where" (posture votes), docs/research/poc-pg-posture-findings.md §"Dependency postures".
• OQ-ST-05, OQ-ST-06 (docs/research/phase-0.md) — the resolution records.
• ADR-003, ADR-004 — the per-engine driver decisions applying this posture.
• OQ-06 (docs/architecture/open-questions.md) — the quality-read tracker.