refactor!: outbox dedup + perf cleanup (remove OutboxWorker stack, batch settlement)

[patrickleet]

Summary

Cleanup of the outbox layer from two independent dedup/perf audits. One commit per finding.

refactor!: remove the vestigial OutboxWorker publish stack (7355637)

Deletes src/outbox_worker/worker.rs + publisher.rs (OutboxWorker, DrainResult, ProcessOneResult, OutboxPublisher, LogPublisher, LocalEmitterPublisher) — a complete second publish pipeline with its own degenerate message shape and an in-memory claim→publish→settle state machine without durable settle, duplicating OutboxDispatcher::dispatch_claimed. Only consumer was tests/todos, now ported to OutboxDispatcher + a recording MessagePublisher. LocalEmitterPublisher was not needed by anything else (the emitter feature's real path is the src/emitter enqueue flow), so it is not recreated; the one test that existed purely to exercise it is dropped. README's two stale mentions updated. No deprecation shims (pre-release).

perf: convert outbox rows to transport messages by value (0bcc085)

The immediate-publish path cloned each staged row into the hook, then From<&OutboxMessage> re-cloned payload + every metadata string. Every dispatch path owns its row at map time, so the conversion is now From<OutboxMessage> and payload/metadata/id/event-type all move.

refactor: one shared publish-then-settle path (5120a10)

dispatch_claimed and BusOutboxPublishHook carried the same publish → complete-or-record_failure sequence. Extracted as publish_and_settle, used by both; the hook never re-claims (rows are claimed inside the commit transaction). OutboxPublishHook::publish_claimed now takes the commit's rows as one Vec batch.

perf: batch outbox settlement + bounded publish concurrency (6e9689a)

• OutboxStore::complete_many (default = serial loop): Postgres settles a batch in one UPDATE … FROM unnest(ids, workers, attempts) with the same per-claim predicate as complete (unapplied claims diagnosed to the same NotFound/InvalidState errors); SQLite runs the per-claim UPDATEs in one transaction (one commit/fsync per batch — an IN-list can't carry the per-claim worker/attempt predicate, so the transaction is the honest batching there); hashmap settles under a single write lock. Backend impls are additive-only (new fns, no restructuring) per the parallel repo-internals work.
• publish_and_settle publishes with bounded concurrency (futures-util buffer_unordered) and settles all successes in one complete_many; failures settle individually.
• OutboxDispatcher::with_publish_concurrency(NonZeroUsize) — defaults to 1 because outbox claim order is created-at order and consumers may rely on it; the after-commit hook always uses 1 (a commit's rows are one aggregate's events). Documented on the option.
• If the batched complete fails, published-but-unsettled rows stay in flight and re-publish at lease expiry — the same at-least-once window a crash between publish and settle always leaves.
• New dep: futures-util (no default features) in core; the runtime-agnostic core stays executor-free.
• New conformance case worker_completes_claims_in_one_batch runs complete_many against hashmap, Postgres, and SQLite.

refactor: shared claim_order_key (cf02f7c)

sort_by_claim_order and claim_order_ids each restated the (created-at, id) ordering; one key fn now defines it.

chore: consolidate test block_on (e5fddcd)

The busy-poll test executor was copy-pasted across outbox_worker test modules; now one #[cfg(test)] util. src/bus/ copies untouched (other agent's area).

Test output

• cargo fmt clean, cargo clippy --workspace --all-features --all-targets clean
• cargo test --workspace --all-features --all-targets (DATABASE_URL → dedicated postgres): all 45 suites pass, including todos, enqueue, sourced_enqueue, durable_enqueue_sqlite, postgres/sqlite repository + conformance (incl. new outbox batch case on both real backends), postgres_transport
• lib tests: 270 passed (+5 new: mixed-outcome settle, concurrency>1, claim-order-on-the-wire, hashmap complete_many happy/stale)
• Note: one unrelated flake observed once in a fully parallel run — distributed_read_model_board::board_service_feeds_a_normalized_card_read_model (in-memory bus/projection test; touches none of the changed paths, passes standalone 5/5 and in the full rerun)

🤖 Generated with Claude Code

https://claude.ai/code/session_01DzYSVLas93c7LbgHJWsW7n

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Review details

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: ad386f04-5956-40da-8722-0078726bbd34

📥 Commits

Reviewing files that changed from the base of the PR and between 6d3272c and fd1be28.

📒 Files selected for processing (21)

• Cargo.toml
• README.md
• src/lib.rs
• src/outbox/commit.rs
• src/outbox/message.rs
• src/outbox_worker/bus_publisher.rs
• src/outbox_worker/mod.rs
• src/outbox_worker/outbox_dispatch.rs
• src/outbox_worker/outbox_source.rs
• src/outbox_worker/publish_hook.rs
• src/outbox_worker/publisher.rs
• src/outbox_worker/store.rs
• src/outbox_worker/testing.rs
• src/outbox_worker/worker.rs
• src/postgres_repo/mod.rs
• src/sqlite_repo/mod.rs
• tests/hashmap_repository_conformance/main.rs
• tests/persistent_repository_conformance/outbox.rs
• tests/postgres_repository_conformance/main.rs
• tests/sqlite_repository_conformance/main.rs
• tests/todos/main.rs

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch review/outbox-dedup-perf

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