91a38dc20b
Scrum iter 11 on crates/vectord/src/index_registry.rs flagged two
concrete field gaps (90% confidence). Both were tagged UnitMismatch
/ missing-invariant.
IndexMeta gains two Optional fields:
last_used: Option<DateTime<Utc>>
PRD 11.3 — when this index was last searched against. Callers
were reading created_at as a liveness proxy, which conflated
"built" with "used." IndexRegistry::touch_used(name) stamps the
field on every hit; incremental re-embed can now skip cold
indexes without misattributing "fresh build" to "recent use."
build_signature: Option<String>
PRD 11.3 — stable SHA-256 of (sorted source files + chunk_size
+ overlap + model_version). compute_build_signature() in the
same module is deterministic: file-order-invariant, changes on
chunk param, changes on model version. Lets incremental re-embed
answer "has anything changed since last build?" without scanning
the source Parquet.
Both fields are #[serde(default)] — the ~40 existing .json meta
files under vectors/meta/ load unchanged. Backward-compat verified
by the explicit `index_meta_deserializes_without_new_fields_backcompat`
test.
7 new tests:
- build_signature_is_deterministic
- build_signature_order_invariant (sorted internally)
- build_signature_changes_on_chunk_param
- build_signature_changes_on_model_version
- touch_used_updates_last_used
- touch_used_is_noop_on_missing_index
- index_meta_deserializes_without_new_fields_backcompat
Call-site fixes: crates/vectord/src/refresh.rs:294 and
crates/vectord/src/service.rs:244 both construct IndexMeta with
fully-literal init, default the new fields to None. One
indentation cleanup on service.rs (a pre-existing visual issue on
id_prefix: None).
Workspace warnings still at 0. touch_used() isn't wired into search
hot-path yet — follow-up commit when the search handlers can
adopt it without a broader refactor.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>