C24 first cut (#155): a blueprint — the param-generic, named graph-as-data a
Rust builder produces — is now a first-class serializable data value with a
canonical, versioned format, and the engine has the missing load path
(data -> blueprint -> FlatGraph), not only the Rust-builder construction path.
What ships:
- `blueprint_to_json` / `blueprint_from_json` in a new `aura-engine`
blueprint_serde module: a faithful serde DTO projection (the build closures
dropped; re-derived on load), top-level `format_version` envelope, canonical
compact JSON (struct field order, defaults omitted via skip_serializing_if).
- A resolver seam: the loader is generic over an injected
`Fn(&str) -> Option<PrimitiveBuilder>`; the concrete closed `match` over the
aura-std vocabulary lives in aura-std (`std_vocabulary`), never in the engine
(the engine stays domain-free: lib deps aura-core + aura-analysis only, never
the node-vocabulary crate). This is C24's compiled-in closed-set referenced by
type identity, NOT a dynamic/marketplace node registry (domain invariant 9).
- serde derives on the serialized plain types (Edge, Target, OutField, Role,
BoundParam, ScalarKind); BoundParam additionally re-exported from aura-core's
root (an additive fix the plan's file list missed).
Load-bearing scope decisions (derived, logged on #155):
- Sinks are excluded from the serialized blueprint — a recording sink captures an
mpsc::Sender (runtime identity, not param/topology, C19 value-empty); sink
addressing is the C18-registry / #101 concern. The round-trip test attaches
identical sinks post-load to both twins.
- Construction-arg builders (LinComb(arity), CostSum(n), SimBroker(pip),
Session(..)) are out of the round-trippable set: their structural args are a
C20 structural-axis concern the param-generic format does not yet encode; an
absent type_id fails the load cleanly (UnknownNodeType), never a silent wrong
graph. #155's vocabulary is the 22 zero-arg aura-std builders. Additively
extensible later (#156).
Orchestrator hardening on review: the serializer now emits bound params in
ascending original-slot order (mirroring the loader), so the canonical form is
bind-order-independent — a precondition for content-addressing (#158). Identity
today (every #155 node has <=1 param); holds by construction for future
multi-param nodes.
Acceptance (all green): a serialized blueprint runs bit-identical (C1) to its
Rust-built twin; serializer/loader are inverse (canonical idempotence, incl. a
recursive nested composite); unknown-type and unsupported-version fail named,
never panicking. cargo test --workspace 748 passed; clippy --all-targets
-D warnings clean.
closes#155
Brummel
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