3-lineage scrum on 434f466..0d4f033 surfaced one convergent finding
(Opus + Kimi) and 3 Opus-only real bugs. All actioned in this
commit. Two false positives (Kimi rollback misreading, Opus stale-
comment claim) verified + rejected — both required manual control-
flow inspection to refute, matching the documented Kimi-truncation
behavior in feedback_cross_lineage_review.md.
Convergent fix — DecodeIndex lost nil-meta items:
- Envelope version bumped 1 → 2.
- New v2 field: IDs []string carries the canonical ID set
explicitly, independent of meta map's nil-vs-{} sparseness.
- DecodeIndex accepts both versions: v2 reads from env.IDs; v1
falls back to meta-key inference (with the documented
limitation that nil-meta items are invisible — preserved for
backward-compat with already-persisted indexes).
- Encode emits v2 going forward.
- 2 new regression tests:
- TestEncodeDecode_NilMetaItemsSurviveRoundTrip: items added
with nil metadata MUST survive Encode → Decode and remain
visible to IDs(). Pre-fix would have yielded IDs() == [].
- TestDecodeIndex_V1BackwardCompat: hand-crafted v1 envelope
still decodes (proves the fallback path).
Opus-only fixes:
- handleMerge: non-ErrIndexNotFound errors at h.reg.Get(name) /
h.reg.Get(req.Dest) now return 500 + log instead of falling
through with nil src/dest pointers (which would panic on the
next deref). Real bug — only the sentinel error was handled.
- internal/drift/drift.go: mathLog wrapper removed; math.Log
inlined. Wrapper added no value (math was already imported).
- internal/distillation/audit_baseline.go: BuildAuditDriftTable's
bubble sort replaced with sort.Slice. Idiomatic + shorter.
Rejected after verification:
- Kimi WARN "missing rollback on partial merge": misread the
control flow. Code at cmd/vectord/main.go:404-414 does NOT
delete from src when dest.Add fails (continue before reaching
src.Delete). Only successful Adds trigger Deletes.
- Opus INFO "TimestampUnixNano comment references missing field":
field exists at scripts/multi_coord_stress/main.go:128. Opus
saw only the diff context, not the full file.
Deferred (no fired trigger):
- Opus WARN "no per-index lock during merge": no concurrent merge
callers today (operators run merge as deliberate one-shot job).
Worth a lock if/when matrixd or chatd start auto-triggering.
Disposition: reports/scrum/_evidence/2026-05-01/verdicts/post_role_gate_v1_disposition.md.
Build + vet + tests green; 2 new regression tests + all prior tests
unchanged.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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