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alkstore/tasks/contract-suite-scaffold.md
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---
id: contract-suite-scaffold
name: Contract-suite crate scaffold + ADR-022 (suite layout decision)
status: completed
depends_on: [core-trait-surface]
scope: narrow
risk: low
impact: phase
level: implementation
tags: [wave-1, contract-suite]
---
## Description
Scaffold the contract suite as a fourth, internal, unpublished crate —
`alkstore-contract-suite` — per the layout decision recorded in
docs/plans/implementation.md (option (a)): property tests
parameterized over a `Store` factory, consumed by each engine crate as
a dev-dependency. This discharges ADR-017 §4.2's "layout decided at
implementation" deferral; the decision gets its own ADR (ADR-022) since
it shapes the pairing instrument ADR-017 §4 names.
The crate:
- Workspace member, `publish = false`, depends on `alkstore` only.
- Exposes a `StoreFactory` trait (or function alias — implementer's
choice, but one shape, documented): something that yields a fresh
`Box<dyn Store>`-shaped store over an isolated backing store (fresh
file / fresh schema), plus teardown. The exact factory shape may
evolve when engines adopt it (wave 3/4 feedback) — the ADR records
the layout decision, not a frozen API.
- A `tests/` harness that runs the property set against a supplied
factory, structured so each backlog row is one named, independently
runnable property with a version-stamp slot (ADR-017 §4.2: each row
version-stamped with the contract change that added it — a
doc-comment or attribute convention, decided here and used by every
later row).
- One exemplar property implemented end-to-end to prove the harness
works — the reserved-name/empty-name validation property (pure
contract, engine-independent, runnable against any factory): every
name-bearing entry point rejects empty with `InvalidName` and
reserved-prefix with `ReservedName`, on auto-commit and tx paths
alike. This row is version-stamped `ADR-008 §4`.
- Engine crates get the dev-dependency edge now (empty suite compiles
against them trivially once they have code; the edge existing early
means wave 3/4 tasks adopt the harness rather than debate it).
## Acceptance Criteria
- [ ] `alkstore-contract-suite` crate exists, `publish = false`,
depends on core only, compiles in the workspace
- [ ] Factory abstraction defined and documented; exemplar property
(name validation) green against a trivial in-crate mock store
- [ ] Version-stamp convention established and documented in the
crate (used by the exemplar row)
- [ ] ADR-022 written (`docs/architecture/decisions/022-contract-suite-layout.md`):
option (a) chosen, rationale (one normative owner per property,
ADR-012 §2 mirror), the factory-shape latitude stated, ADR-017
§4.2 deferral discharged; ADR index tables in
docs/architecture/README.md and overview.md updated
- [ ] Engine crate manifests carry the dev-dependency edge
- [ ] `cargo test` workspace-wide, clippy `-D warnings`, fmt clean
## References
- docs/architecture/decisions/017-contract-versioning.md §4.2
- docs/plans/implementation.md (Decided points)
- docs/architecture/core-contract.md §Verification backlog
## Notes
- **Factory shape (the implementer's choice)**: a named trait,
`StoreFactory { open() -> BoxedFuture<Result<Box<dyn Store>>>;
teardown() -> BoxedFuture<Result<()>> }` — chosen over a function
alias because teardown needs an identity to be idempotent *per
instance* (a bare fn can't carry "this factory's backing store"),
and the async surface rides core's `BoxedFuture` posture so
implementers need no macros. One shape, documented in
`src/factory.rs`; the ADR records the layout, not a frozen API —
wave 3/4 feedback may evolve it.
- **Version-stamp convention (the "decided here" row convention)**:
a row's doc comment carries one `Contract stamp:` item per contract
change pinning the behavior tested, citing ADR § (never bare "v1"
or dates); stamps *accumulate* on amendment; greppable via the
exported `STAMP_MARKER` constant. Normative statement lives in
`src/version_stamp.rs` — every later row cites against it. The
exemplar row is stamped `ADR-008 §4` + `ADR-021 §3` + `ADR-015 §2`
(its assertions span all three changes' behavior).
- **Assertion posture**: rows panic on violation (labeled with the
entry point and expectation) — the test-side-artifact relaxation of
the family no-panic rule, documented in the crate docs as
deliberate.
- **Exemplar scope**: the property runs the full validation surface —
all four `Store` constructor kinds (`listen`/`stream`/`queue`/
`outbox`), `try_lock` (both name and owner), `schedule` (both name
and queue argument — ADR-021 §3), `notify`, and *every* name-bearing
`*_tx` twin on `TxHandle` (all eleven, incl. ADR-015 §2's
non-empty-key rule on `publish_with_key_tx`), plus a `with_tx`
spot-check proving the commit-atomic path can't bypass validation.
Happy-path spot-checks (`stream`/`queue`/`try_lock` with a
reserved-prefixed owner) prove the rejections are the validation's
doing, not store-wide failure.
- **`Schedule` is `#[non_exhaustive]`** (ADR-017 §3): the mock cannot
struct-construct it, so the mock's `schedule()` returns a `Database`
stub after running the row-validation; the row asserts only the
validation outcomes, and `Schedule` construction stays core's own
tests' business. Same for the mock's `subscribe` (never exercised by
the row). Noted so wave 3/4 factory impls copy the posture knowingly.
- **serde_json is a direct dep of the suite** (not just core's): rows
construct payload `Value`s as contract surface (ADR-020 §4's trait
crossing). No driver deps — the ADR-001 §2 mirror holds.
- **Dev-dep edges are path deps** (`path = "../alkstore-contract-suite"`)
with no version: correct for an unpublished internal crate — a
`version` key would be meaningless.
- ADR-017 §4.2's text gained a layout-resolution annotation (dated,
citing ADR-022) at the deferral site — the discharge is visible from
the deferring document itself.
## Summary
The `alkstore-contract-suite` crate is scaffolded per the option-(a)
layout decision: `publish = false`, workspace member, depends on
`alkstore` only (+ serde_json for payload construction). It defines
the `StoreFactory` trait (open/teardown over an isolated backing
store), the version-stamp convention (`Contract stamp:` doc-comment
items, `STAMP_MARKER` constant, normative statement in
version_stamp.rs), and the exemplar property
`name_validation_rejects_empty_and_reserved` — full auto-commit + tx
validation surface, stamped ADR-008 §4 / ADR-021 §3 / ADR-015 §2. A
`tests/suite_harness.rs` runs it green against a trivial in-crate mock
store + factory (3 tests: the exemplar row, happy-path construction,
stamp-marker check). Engine crates carry the dev-dependency edge
(path-dep). ADR-022 written
(docs/architecture/decisions/022-contract-suite-layout.md): option (a)
chosen, one-normative-owner-per-property rationale (ADR-012 §2
mirror), factory-shape latitude stated, ADR-017 §4.2 deferral
discharged (with an annotation added at the deferral site);
ADR index tables in docs/architecture/README.md and overview.md
updated. Workspace `cargo build`, `cargo test` (26 tests workspace
wide), `cargo clippy --all-targets -- -D warnings`, `cargo fmt
--check` all clean.