Closes a bypass surfaced by the 2026-04 audit probe (axis-1 Q2): any
authenticated user could POST /api/v1/subscriptions/subscribe on a paid
plan and receive 201 active without the payment provider ever being
invoked. The resulting row satisfied `checkEligibility()` in the
distribution service via `can_sell_on_marketplace=true` on the Creator
plan — effectively free access to /api/v1/distribution/submit, which
dispatches to external partners.
Fix is centralised in `GetUserSubscription` so there is no code path
that can grant subscription-gated access without routing through the
payment check. Effective-payment = free plan OR unexpired trial OR
invoice with non-empty hyperswitch_payment_id. Migration 980 sweeps
pre-existing fantôme rows into `expired`, preserving the tuple in a
dated audit table for support outreach.
Subscribe and subscribeToFreePlan treat the new ErrSubscriptionNoPayment
as equivalent to ErrNoActiveSubscription so re-subscription works
cleanly post-cleanup. GET /me/subscription surfaces needs_payment=true
with a support-contact message rather than a misleading "you're on
free" or an opaque 500. TODO(v1.0.7-item-G) annotation marks where the
`if s.paymentProvider != nil` short-circuit needs to become a mandatory
pending_payment state.
Probe script `scripts/probes/subscription-unpaid-activation.sh` kept as
a versioned regression test — dry-run by default, --destructive logs in
and attempts the exploit against a live backend with automatic cleanup.
8-case unit test matrix covers the full hasEffectivePayment predicate.
Smoke validated end-to-end against local v1.0.6.2: POST /subscribe
returns 201 (by design — item G closes the creation path), but
GET /me/subscription returns subscription=null + needs_payment=true,
distribution eligibility returns false.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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