Iter 13. Lands ADR-121 §2.1 (output event) + ADR-122 §2.1 (field-gating
policy). BfldEvent collapses the GateAction-driven sensing pipeline
into the canonical wire-format publishable on MQTT.
Added:
- serde (workspace, derive feature, optional) + serde_json (workspace, optional) deps
- New crate feature `serde-json` (default-on; requires `std`)
- src/event.rs (gated on `feature = "std"`):
* BfldEvent struct with all sensing + identity-derived fields
* with_privacy_gating(...) constructor that applies field-gating policy:
class < Restricted (3): identity_risk_score + rf_signature_hash kept
class >= Restricted (3): both nulled to None
* apply_privacy_gating() — idempotent in-place masking
* to_json() -> Result<String, serde_json::Error> (gated on serde-json)
* Custom ser_privacy_class serializer emits lowercase names
("anonymous", "restricted", etc.) per the BFLD JSON spec
* skip_serializing_if = "Option::is_none" on identity-derived fields so
privacy-gated events are observationally indistinguishable from
events that never had the field set
- pub use BfldEvent from lib.rs
tests/event_privacy_gating.rs (9 named tests, all green):
anonymous_event_retains_identity_risk_and_hash
restricted_event_strips_identity_fields (class 3 → None)
apply_privacy_gating_is_idempotent
event_type_is_always_bfld_update (parameterized over 3 classes)
json::json_round_trip_emits_type_field_first_or_last_but_present
json::anonymous_json_includes_identity_fields
json::restricted_json_omits_identity_fields_entirely
(asserts the JSON string does NOT contain identity_risk_score or
rf_signature_hash, verifying skip_serializing_if works as intended)
json::privacy_class_serializes_to_lowercase_name
json::zone_id_none_is_omitted_from_json
ACs progressed:
- ADR-121 AC6 (identity_risk score absent at class 3) — structurally
enforced by with_privacy_gating + skip_serializing_if combination.
- ADR-122 AC1 — JSON shape matches the HA-DISCO publishable event
contract; identity fields can be reliably stripped by privacy_class.
- ADR-118 AC5 — privacy_mode = engaged maps to PrivacyClass::Restricted
with no identity fields in the published event.
Test config:
- cargo test --no-default-features → 64 passed (unchanged; event cfg-out)
- cargo test → 102 passed (93 + 9)
Out of scope (next iter target):
- Emitter struct that wires GateAction + privacy class + sensing inputs
into BfldEvent construction (ADR-118 §2.1 pipeline diagram).
- MQTT topic publisher (ADR-122 §2.2) — depends on a runtime (tokio).
Co-Authored-By: claude-flow <ruv@ruv.net>
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