Core value types: opts structs, Job/JobState, Schedule, StreamEvent, Wake, StopToken, payload encode/decode (ADR-008 §1/§3, ADR-010 §3, ADR-015 §3, ADR-017 §3, ADR-019 §3/§4, ADR-020 §1–§4, ADR-021 §2)

tasks/core-value-types.md

@@ -1,7 +1,7 @@
 ---
 id: core-value-types
 name: Core value types (opts, Job, Schedule, StreamEvent, Wake, StopToken)
-status: pending
+status: completed
 depends_on: [core-errors-and-validation]
 scope: narrow
 risk: low
@@ -68,14 +68,14 @@ part of the contract.
 
 ## Acceptance Criteria
 
-- [ ] All types above with the exact pinned fields/types/derives;
+- [x] All types above with the exact pinned fields/types/derives;
       `#[non_exhaustive]` on read types, absent on opts structs
-- [ ] `Default` impls: `EnqueueOpts` (all-None/0), `QueueOpts`
+- [x] `Default` impls: `EnqueueOpts` (all-None/0), `QueueOpts`
       (300/3/5/None), `ScheduleOpts`
-- [ ] `payload_as<T>` round-trips a serde_json `Value` through encode →
+- [x] `payload_as<T>` round-trips a serde_json `Value` through encode →
       decode; non-serializable target type yields `Codec`
-- [ ] `StopToken`: cancel on a clone flips all clones; unit-tested
-- [ ] `cargo test -p alkstore`, clippy `-D warnings`, fmt clean
+- [x] `StopToken`: cancel on a clone flips all clones; unit-tested
+- [x] `cargo test -p alkstore`, clippy `-D warnings`, fmt clean
 
 ## References
 
@@ -88,8 +88,57 @@ part of the contract.
 
 ## Notes
 
-> To be filled by implementation agent
+- `serde`/`serde_json` added to `alkstore` (ADR-020 §4 names them the
+  core crate's only deps beyond thiserror; used without the `derive`
+  feature — the trait crosses `serde_json::Value`, never generic
+  trait methods, so no derive machinery lives in core).
+- Module layout: `src/opts.rs` (the three opts structs),
+  `src/job.rs` (`Job` + `JobState`), `src/schedule.rs`,
+  `src/stream.rs` (`StreamEvent`), `src/wake.rs`,
+  `src/stop_token.rs`, `src/payload.rs` (the encode/decode helpers),
+  re-exported from `src/lib.rs`.
+- Encode helper named `encode_payload(&Value) -> Vec<u8>` — infallible
+  at the type level (serializing a `serde_json::Value` cannot fail;
+  the `unwrap_or_else` fallback is the unreachable empty vec, and
+  core holds no panic posture to break: it serializes, never
+  constructs, Values in engine paths). `payload_as<T:
+  DeserializeOwned>(bytes)` is the shared decode used by
+  `Job::payload_as` and `StreamEvent::payload_as`;
+  `Error::Codec(e.to_string())` on failure.
+- "Non-serializable target yields Codec" is realized as a
+  runtime-decode failure test (target type statically decodable but
+  structurally mismatched with the stored bytes, plus non-JSON
+  bytes) — a type with no `Deserialize` impl cannot compile through
+  `payload_as`'s `DeserializeOwned` bound, so the Codec error is the
+  runtime arm by construction.
+- ADR-019 §3's `Job` field list carried *as corrected by ADR-021 §2*
+  (`claimed_at` present, `None` pre-claim). `JobState` derives
+  `Copy` (small field-set enum, read-only value). Opts structs derive
+  `Debug/Clone/PartialEq/Eq` (+`Default` per the pinned defaults);
+  read types derive `Debug/Clone/PartialEq/Eq`.
+- `StopToken` = `Arc<AtomicBool>` with `Ordering::SeqCst`; `new()`
+  and `Default` both construct uncancelled; doc text carries the
+  engine-internal watch-channel note (ADR-019 §4) and the
+  clean-stop/LeadershipLost split.
 
 ## Summary
 
-> To be filled on completion
+Core value types implemented in `alkstore`: `EnqueueOpts`/
+`QueueOpts`/`ScheduleOpts` (exact pinned fields, hand-written
+`QueueOpts` `Default` = 300/3/5/None, derived defaults for the other
+two — all-`None`/priority 0); `Job` (ADR-019 §3 field list + ADR-021
+§2's `claimed_at`) and `JobState::{Pending, Processing, Dead}`;
+`Schedule`; `StreamEvent`; `Wake`; all read types `#[non_exhaustive]`,
+none of the opts structs; `Job::payload_as`/`StreamEvent::payload_as`
+over the shared `payload::payload_as` + `encode_payload` helpers
+(ADR-020 §4); `StopToken` (`Arc<AtomicBool>`, clone-flips-all).
+Doc comments carry the pinned semantics text (delay-over-run_at,
+relative expires, stamped QueueOpts, heartbeat is engine-side and
+absent here, wake = channel-only hint, reconnect-wake constant
+reference). Ten new unit tests (20 total in the crate) cover the
+pinned defaults, a full JSON round-trip through
+`encode_payload` → `Job`/`StreamEvent` → `payload_as` for `Value` and
+concrete typed targets, Codec failures, clone-flip stop semantics,
+and independent-token isolation. `cargo test -p alkstore` (20 pass),
+`cargo clippy --all-targets -- -D warnings`, `cargo fmt --check`, and
+workspace `cargo build` all clean.