Fix round 1 for Task 7, addressing review findings against the brief's
own memoKey design (now superseded per plan amendment cc8085bc):
- C1: memoKey's String(id) + JSON.stringify-with-catch cross-authorized
distinct resources whenever their ids stringified the same (numeric
vs string ids, object-shaped ids) or whenever JSON.stringify threw
(circular references, BigInt fields, throwing getters all shared one
"<unserialisable>" bucket, so the first verdict computed for any of
them became the cached verdict for all of them in that request).
- C2: filterCan inherited the same bypass, returning rows the subject
could not act on.
- Replaced serialisation-based memoization with identity-based
memoization: object resources are memoised in a WeakMap keyed by the
resource reference itself (never serialised), primitives/absent
resources in a Map keyed by [scope, permission, typeof, String(value)]
so 7 and "7" can never collide.
- I1: scope is now read from ctx.tenant at decision time (currentScope),
not captured once at middleware-install time, so a tenant switch
mid-request is honoured on the next check.
- I2/M1: guardPermission's redirectTo now only fires for non-JSON/API
requests (replicated wantsJson check, since authz may only import
core as types) and only for a validated local path (isLocalPath),
closing an open-redirect and a JSON-caller-follows-303 gap.
- I3: getResource is now wrapped in try/catch; a throw denies with the
standard opaque 403 body instead of propagating the loader's error
(e.g. a SQL string) to the client.
- Added cache-control: private, no-store to both the 303 and 403
responses.
Added 11 regression tests. C1/C2 revert-checked: temporarily restored
the old memoKey design and confirmed the four collision tests fail
against it before restoring the fix.
Installs a per-request authz resolver via authzMiddleware and exposes
can()/decideFor()/guardPermission()/filterCan() as free functions (not
Context members, so @wrnexus/core stays free of an authz dependency).
All four route through resolver.decide(), never permissionsFor(), so
resource-scoped policy denials can't be bypassed via the coarse
permission set. Per-request results are memoised keyed on (permission,
resource) to avoid re-hitting the store within a request without
leaking one resource's verdict onto another.
Clintchiz