Re-review of Task 6's fix round 1 (plan amendment d6a2d054) found three
items in that diff plus one adjacent pre-existing issue that C1 made
reachable:
- Important (perf): permissionsFor() rebuilt the deny Set on every
entry in the granted set (O(grants x denies) allocations on a
per-request path). Hoisted to build the Set once. Measured
4000x4000: 665.92ms before, 3.90ms after.
- Important (contract accuracy): permissionsFor() only half-agrees
with decide() — a narrow deny under a broad grant (e.g. role editor's
"post:*" plus a deny on "post:delete") can't be represented in a flat
Set, so the set still contains "post:*" while decide() correctly
refuses "post:delete". Documented as NOT authoritative on the
AuthzResolver interface, and pinned with a regression test asserting
the divergence is deliberate.
- Minor: subject.id === "" was audited as subjectId: "" instead of
omitted, so consoleAuditSink printed a blank subject= rather than
subject=anonymous. Reused the same non-empty-string guard as the
decide() path.
- Important (adjacent, advanced.ts): owner() compared subject[key] to
resource[key] with Object.is without checking either side was
present, so two absent ids (Object.is(undefined, undefined) ===
true) satisfied ownership. Unreachable before this task, but C1 now
runs bound policies for anonymous/empty subjects, putting this on a
live path. Fixed to deny whenever either side is undefined or null.
Every fix's regression test was verified by reverting the fix and
confirming the test fails against the pre-fix code before restoring.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>