fix(billing): let a catalog price decide the product, and check the session lookup key

CodeRabbit follow-up. Stripe updates a subscription's price and its metadata
independently, so when the plan sits on a catalog price (ever_<any>_...) that
price now decides, and ever_product metadata may only agree with it. Metadata
alone decides only when the plan has no catalog lookup key. A Checkout
Session's metadata.ever_lookup_key, when present, must be one of this
product's ever_<product>_cloud_ prices.

A read-only live check found every ever.co session stamps a consistent
ever_lookup_key, and all 63 Gauzy subscriptions sit on ever_gauzy_cloud_
prices, so no current buyer is affected. 7 suites, 161 tests pass locally.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/core/src/lib/shared/billing/billing-product.ts

@@ -137,6 +137,11 @@ export interface ProductScopedCheckoutSession {
  *
  * A self-hosted license of the same product is refused on either signal: `ever_hosting` other than
  * `cloud`, or a plan price of this product that is not an `ever_<product>_cloud_` price.
+ *
+ * When the plan sits on a catalog price (`ever_<any>_...`), the price decides and the metadata may
+ * only agree with it. Stripe updates a subscription's price and its metadata independently, so a
+ * Teams price under `ever_product: 'gauzy'` metadata (or the reverse) is not this product's plan.
+ * The metadata alone decides only when the plan has no catalog lookup key.
  */
 export function subscriptionIsForProduct(
 	subscription: ProductScopedSubscription | null | undefined,
@@ -145,36 +150,40 @@ export function subscriptionIsForProduct(
 	if (!subscription || !product) return false;
 	if (!hostingIsCloud(subscription.metadata)) return false;
 	const lookupKey = subscription.items?.data?.[0]?.price?.lookup_key;
-	const cloudPrefix = cloudLookupKeyPrefix(product);
-	if (
-		typeof lookupKey === 'string' &&
-		lookupKey.startsWith(lookupKeyPrefix(product)) &&
-		!lookupKey.startsWith(cloudPrefix)
-	) {
-		return false;
+	const metadataProduct = subscription.metadata?.ever_product;
+	if (typeof lookupKey === 'string' && CATALOG_LOOKUP_KEY.test(lookupKey)) {
+		return lookupKey.startsWith(cloudLookupKeyPrefix(product)) && (!metadataProduct || metadataProduct === product);
 	}
-	if (subscription.metadata?.ever_product === product) return true;
-	return typeof lookupKey === 'string' && lookupKey.startsWith(cloudPrefix);
+	return metadataProduct === product;
 }
 
+/** Any catalog lookup key: `ever_<product>_<hosting>_...`. */
+const CATALOG_LOOKUP_KEY = /^ever_[a-z0-9]+_/;
+
 /**
  * Whether a completed Checkout Session is a purchase of `product`'s HOSTED plan that can establish a
  * tenant link.
  *
- * All three are required. `mode === 'subscription'` excludes payment-mode sessions (lifetime
- * licenses, Ever Works credit packs) and setup-mode card saves, none of which buys a hosted plan;
- * the hosting check excludes self-hosted license subscriptions (`ever_hosting: 'selfhosted'`).
+ * All are required. `mode === 'subscription'` excludes payment-mode sessions (lifetime licenses,
+ * Ever Works credit packs) and setup-mode card saves, none of which buys a hosted plan; the hosting
+ * check excludes self-hosted license subscriptions (`ever_hosting: 'selfhosted'`); and a
+ * `metadata.ever_lookup_key`, which the shared checkout stamps on every session, must be one of this
+ * product's cloud prices when it is present.
  */
 export function checkoutSessionIsForProduct(
 	session: ProductScopedCheckoutSession | null | undefined,
 	product: string | null | undefined
 ): boolean {
 	if (!session || !product) return false;
-	return (
-		session.metadata?.ever_product === product &&
-		session.mode === 'subscription' &&
-		hostingIsCloud(session.metadata)
-	);
+	if (
+		session.metadata?.ever_product !== product ||
+		session.mode !== 'subscription' ||
+		!hostingIsCloud(session.metadata)
+	) {
+		return false;
+	}
+	const lookupKey = session.metadata?.ever_lookup_key;
+	return !lookupKey || lookupKey.startsWith(cloudLookupKeyPrefix(product));
 }
 
 /**

packages/core/src/lib/shared/billing/stripe-subscription.service.spec.ts

@@ -163,6 +163,15 @@ describe('billing-product predicates', () => {
 				'gauzy'
 			)
 		).toBe(false);
+		// The price decides when it is a catalog price; metadata may only agree with it.
+		expect(
+			subscriptionIsForProduct(teamsSub({ metadata: { ever_product: 'gauzy', ever_hosting: 'cloud' } }), 'gauzy')
+		).toBe(false);
+		expect(subscriptionIsForProduct(gauzySub({ metadata: { ever_product: 'teams' } }), 'gauzy')).toBe(false);
+		// Metadata alone decides only when there is no catalog price.
+		expect(
+			subscriptionIsForProduct(gauzySub({ items: { data: [{ price: { lookup_key: null } }] } }), 'gauzy')
+		).toBe(true);
 		// A catalog price of this product that is not a cloud price.
 		expect(
 			subscriptionIsForProduct(
@@ -198,6 +207,14 @@ describe('billing-product predicates', () => {
 				'gauzy'
 			)
 		).toBe(false);
+		// A stamped lookup key must be one of this product's cloud prices.
+		const withKey = (ever_lookup_key: string) => ({
+			mode: 'subscription',
+			metadata: { ever_product: 'gauzy', ever_hosting: 'cloud', ever_lookup_key }
+		});
+		expect(checkoutSessionIsForProduct(withKey('ever_gauzy_cloud_starter_annual'), 'gauzy')).toBe(true);
+		expect(checkoutSessionIsForProduct(withKey('ever_gauzy_selfhosted_enterprise_annual'), 'gauzy')).toBe(false);
+		expect(checkoutSessionIsForProduct(withKey('ever_teams_cloud_starter_monthly'), 'gauzy')).toBe(false);
 	});
 
 	it('recognizes Checkout Session ids and nothing else', () => {

packages/core/src/lib/shared/billing/stripe-webhook.controller.spec.ts

@@ -397,6 +397,28 @@ describe('StripeWebhookController — foreign events are acknowledged with no DB
 				}
 			})
 		],
+		[
+			'Gauzy-stamped session whose lookup key is a self-hosted price',
+			'checkout.session.completed',
+			session({
+				metadata: {
+					ever_product: 'gauzy',
+					ever_hosting: 'cloud',
+					ever_lookup_key: 'ever_gauzy_selfhosted_enterprise_annual'
+				}
+			})
+		],
+		[
+			'ever_product=gauzy metadata on a Teams price',
+			'customer.subscription.created',
+			subscription({
+				status: 'active',
+				metadata: { ever_product: 'gauzy' },
+				items: {
+					data: [{ id: 'si_t', price: { id: 'price_t', lookup_key: 'ever_teams_cloud_starter_monthly' } }]
+				}
+			})
+		],
 		[
 			'subscription with neither metadata nor a lookup key',
 			'customer.subscription.created',