Stage 11 · L48

Integrate and review the final Equipment Rental feature

Optional supplement · original Session 10

Optional resource implementation checked in isolated PostgreSQL/HTTP fixtures.

Native checkpoint 09

Use the starter for this stage's focused examples. The cumulative transfer and solution belong at the stage-end capstone. Baseline checks pass; transfer checks initially fail. Downloads contain the matching native starter and solution for this stage.

The final handover exercise connects earlier boundaries rather than adding an unrelated endpoint. Check-in authenticates the current actor, checks action permission, coordinates the equipment/rental locks, changes active state and creates one audit fact in the same transaction. Repeated check-in does not produce another audit.

Use the final snapshot's starter and write only the missing atomic audit behavior. Preserve the public RentalOut shape and repeat semantics. The successful branch must flush the state change, add the audit and finish both before returning success. A forbidden actor must be rejected before any stored effect.

The second-write failure test intentionally violates the audit CHECK after the first UPDATE. An independent session then reads active state and zero audits. That is real rollback evidence across the full operation, not a mocked method call. Expected public uniqueness/reference conflicts remain409; an internal audit defect is a safe500.

Prepare a handover that names the checkpoint/revision, actual suite and scope limits. The final optional resource checks exercise real async PostgreSQL and an in-process background task; the captured mailbox does not send mail, the provider is local, and debugger/quality/hosted-CI/federation checks are not certified.

Do not convert this local handover into a production deployment. Current progress IDs/downloads remain v1; revision progress migration is a proposal without automatic completion credit. Audit retention, real provider/mail adapters, release compatibility and publication approvals remain explicit decisions.

Current actor + permitted action; Shared lock + state transition; Audit in the same transaction; Real failure + fresh-session proof; Release review remains separate

Follow the running code

Focused lesson example; see the end-of-stage capstone for the cumulative app · stage 09

Handover: exact changed revision/checkpoint
Success, denial, repeat and second-write rollback evidence
Actual passed/failed/not-run checks
Content/progress/adapter/privacy/deployment decisions still pending

Predict and observe this focused example using the concepts explained above. Its boundary is stated in the focused answer.

Guided lab

Read the explanation and predict the focused example’s outcome.
Write a handover for the already-completed core audit feature. Do not implement a new untaught endpoint.
Compare the observed outcome with the focused answer and state its boundary.

Expected: Describe the state+audit operation and matching revision, distinguish real PostgreSQL effects from mocked wiring, and name optional/manual/concept limits. Include no automatic v1 completion credit, no production deployment claim and no invented legal/retention approval. The integration answer summarizes previously taught work.

A private handover does not deploy; audit retention and progress migration are not silently decided.

Focused exercise and answer

Complete this focused exercise before reading its answer. The full native transfer is introduced only at the end of the stage.

Your transfer task: Write a handover for the already-completed core audit feature. Do not implement a new untaught endpoint.

Write a handover for the already-completed core audit feature. Do not implement a new untaught endpoint.

Inspect the matching answer

This answer addresses the focused exercise above; the cumulative implementation is shown only after the stage prerequisites.

Describe the state+audit operation and matching revision, distinguish real PostgreSQL effects from mocked wiring, and name optional/manual/concept limits. Include no automatic v1 completion credit, no production deployment claim and no invented legal/retention approval. The integration answer summarizes previously taught work.

Check your reasoning

What belongs in the final evidence?

Show the explanation

The exact changed operation and revision, real passed/failed/not-run checks, protected effects and remaining release decisions.

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