Invariant 20 checks measure/meter agreement and boundary consistency, and
nothing else: invariant 10 already checks that a measure's signature reference
resolves, so 20 never re-checks it. A None signature avoids only the agreement
clause -- inherited meter still governs distance. Where agreement or delta is
not computable the invariant ABSTAINS rather than failing closed, the deliberate
opposite of create_measure, because base-ingested data may predate the rule.
Pickup first measures are exempt.
epiphany-ops depends on epiphany-core and never the reverse, so invariant 20
cannot reuse packet 1's reducer predicates and implements the comparable
relation and delta a second time over the graph alone. Two implementations of
one normative relation is a divergence hazard, so a cross-crate agreement test
drives a table of anchor pairs through both and a one-sided perturbation signs
it.
SetMetricGrid and SetTimeSignature now refuse writes that would break either
clause for a live measure, and every check precedes the mint -- set_time_signature
previously minted its carried signature before writing the chain, so a refusal
appended afterward would leak a TimeSignature from a non-transactional operation
with no undo to reclaim it.
Undo restoration safety is evaluated in aggregate, because individually-unsafe
restorations can be jointly safe and the reverse. StrictInverse conflicts on the
whole set; BestEffort applies the maximal safe subset under a documented
canonical-order greedy. These are the first callers to pass overlapping
overrides into the grid oracle, so they meet packet 1's tie-break for real.
Both aggregate paths are signed end-to-end as well as by unit test: the measures
are created after the transaction commits, so nothing disagrees on the forward
path and only the restoration of the older grid conflicts. Deleting either call
site was previously invisible to the whole suite.
Executed against spec/CONTRACT_GENESIS_G3B_MEASURE.md, mutations M34-M47.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QjsEnYhm1gPpf6ii2iFxFV
Levi Neuwirth
314cd7a80d