When every resource dep of a node re-enters an ancestor's lock, `owned_reqs`
is empty; the old code still called `acquire(vec![])` and stored a no-op
empty guard in `owned`. Gate the acquire + guard insertion on
`!owned_reqs.is_empty()` — one fewer `borrow_mut` + `HashMap` entry per
fully-re-entrant node in the settle loop. `node_owns` already treats a
missing `owned` entry as non-owning, so behaviour is unchanged.
Make the resource lock unmisusable from outside the crate: the public
surface is now purely declarative (build a Graph with Dep::Resource edges,
configure capacities, run the Scheduler), and the scheduler owns every
acquire/release — a consumer never holds a guard, so it cannot hold the
lock wrong.
- `guard` module + `ResourceTable::try_acquire_all`/`release_all` +
`Graph::set_state` are now `pub(crate)`.
- Remove the dead borrowed-guard layer (`ResourceGuard::borrowed`,
`Acq::Borrowed`, `is_owning`): the scheduler tracks re-entrancy via its
own single borrow slot per (holder, resource) and never constructs a
borrowed guard, so re-entrancy lives in exactly one place. `Acq`
collapses into the owning `ResourceGuard` struct.
- `#[must_use]` on `Scheduler::settle` — ignoring its ids silently drops
runnable work.
- `SharedResources::with` (test-only table observability) is `#[cfg(test)]`.
- Drop the moot borrowed-guard tests; retained owning tests are black-box,
and the redundant `set_state` test helper is gone.
Replace the concrete ResourceName(String) with a type parameter
R: Clone + Eq + Hash threaded end-to-end (Dep<R>, Node<N,R>, Graph<N,R>,
ResourceTable<R>, ResourceGuard<R>/SharedResources<R>, Scheduler<N,R>).
The crate no longer hard-codes the resource identity; the consumer picks
the concrete type (a String, or an enum like BuildSlot/Agent(name)) at
the port. Tests use String as the concrete R. Pure type-parameter
thread-through, no logic change. 25 tests green, clippy pedantic clean.
Named counting-semaphore resources — the Dep::Resource side of the v2
model. A ResourceTable tracks per-name capacity + held counts; unconfigured
names default to capacity 1 (created lazily). try_acquire_all grants every
requested unit or none, leaving the table untouched on failure — so a node
never holds one resource while waiting for another, which is what makes the
scheduler deadlock-free without cycle detection. Duplicate names in a
request are summed; over-capacity requests can never acquire. release_all
saturates rather than underflowing. Runtime scheduler state, not persisted:
held counts are rederived from running nodes on restart. Guard objects
(RAII release, recursive re-entrancy) wrap this in a follow-up.
Per mara's direction — validate ids as they enter the graph so internal
iteration can trust every id the graph holds; the generational route for
removal comes later. Adds GraphError; insert() now rejects a dangling
Dep::Node / parent id (it is fallible); validate() checks all internal id
references resolve and that next_id is past the largest existing id;
deserialization runs validate() via #[serde(try_from = "GraphData<N>")], so
a loaded graph can never carry a dangling reference. 5 new tests; serde_json
added as a dev-dependency for the round-trip cases.
argus flagged that `NodeId(pub u64)` contradicted the "opaque" doc — a pub
inner field lets callers fabricate `NodeId(42)`. Make the field `pub(crate)`
so an id can only originate from the graph's monotonic counter or serde
deserialization, never a caller. Tests construct ids in-crate (unaffected);
the derived Serialize/Deserialize round-trips fine. Doc keeps "opaque" — now
accurate — with a line explaining the enforcement.
group_terminal checked only that every child was terminal, never the group
node's own state — so an empty group whose node is still Running returned
true (empty .all()), making a running node that has yet to append its
subgraph look already-finished. Now it requires the group node itself
terminal AND every child recursively terminal. Deciding when to settle a
group node to terminal once its children are done stays a scheduler concern;
this answers the dependents' question — is the whole group, node included,
finished. Adds group-node-pending-with-child-done + empty-running-group tests.
First step of extracting the job-DAG queue into a domain-agnostic
`hive-jobq` library, per the operator's v2 design: one persistent
graph, named-counter resources, recursive node groups, opaque stable
node ids, guard-object locks, a slot-filling scheduler.
This commit lands only the data model, so the shape can be reviewed
before the machinery is built on it:
- NodeId: opaque, stable, monotonic; group membership is a parent
edge, not encoded in the id (the 1/1/2 hierarchy is a derived UI
label).
- ResourceName, Dep (Node | Resource{name,count}), State.
- Node<N>: caller-defined payload N so the library stays
container-agnostic.
- Graph<N>: insert (mints stable ids), node lookup, children,
recursive group-terminal check. Retains completed groups (no
pruning in v1).
The resource-acquisition machinery (atomic all-or-nothing acquire),
the recursive-lock guards, and the scheduler loop are follow-ups.
Tests cover id minting, group terminality, and state terminality;
clippy + rustdoc clean.
