[match] fix issue where private room subroom join was not marked as private

apps/match/src/match.app.ts

@@ -750,6 +750,17 @@ function persistenceVersionRefusal(
  */
 const ROOM_IS_PRIVATE = MatchmakingErrorCode.RoomIsPrivate
 
+/**
+ * Whether a room is PUBLISHED — Public, or Unlisted (reachable by whoever holds the id,
+ * just not listed). Every other accessibility (Private, and the two Dev_ ones) is a room
+ * its owner hasn't released.
+ */
+function isPublished(room: Room): boolean {
+	return (
+		room.Accessibility === Accessibility.Public || room.Accessibility === Accessibility.Unlisted
+	)
+}
+
 /**
  * Whether a room MATCHMAKE may enter this room at all, before any instance is found or
  * made. A PUBLISHED room — Public, or Unlisted (reachable by whoever holds the id, just
@@ -768,12 +779,7 @@ const ROOM_IS_PRIVATE = MatchmakingErrorCode.RoomIsPrivate
  * their guests through the invite routes, not this one.
  */
 async function canEnterRoom(db: D1Database, room: Room, accountId: number): Promise<boolean> {
-	if (
+	if (isPublished(room)) return true
-		room.Accessibility === Accessibility.Public ||
-		room.Accessibility === Accessibility.Unlisted
-	) {
-		return true
-	}
 	if (room.CreatorAccountId === accountId) return true
 	if (roomRoles(room).some((r) => r.AccountId === accountId && r.Role !== Role.None)) return true
 	return hasRoomInviteTo(db, accountId, Number(room.RoomId))
@@ -1468,6 +1474,16 @@ async function resolveRoomInstance(
 		return { instance: null, errorCode: ROOM_IS_PRIVATE }
 	}
 
+	// An unpublished room has no PUBLIC instances, whatever `JoinMode` asked for. The gate
+	// above only decides who may START a session; a public one is then a door for everyone
+	// it never admitted — a friend follows the owner in, and `IsPrivate: false` tells every
+	// client the session is open. The owner walking through their own room's subroom door
+	// posts `JoinMode` 0, so this has to be decided here rather than trusted from the body.
+	// Private means a fresh instance each time, as `JoinMode` 2 always has: the room's
+	// people reach each other by invite. Room routes only, like the gate — an event or a
+	// clubhouse held in a private room is a session its own guest list shares.
+	const privateInstance = isPrivate || (gateOnAccessibility && !isPublished(room))
+
 	// The build this player is on, from their token. A 2023 client can't load a scene
 	// saved at a newer persistence version, so it is refused the room outright (see
 	// persistenceVersionRefusal) before any instance is created or reused.
@@ -1489,7 +1505,7 @@ async function resolveRoomInstance(
 	// search, which pushes them to another live instance if one exists or forces a
 	// fresh one below. (Only the public path reuses instances, so only it needs the
 	// read; a private matchmake always gets a fresh instance.)
-	const currentInstanceId = isPrivate
+	const currentInstanceId = privateInstance
 		? undefined
 		: (await getPresence<RoomInstance>(c.env.DB, ownerId))?.roomInstance?.roomInstanceId
 	// The same build, with GAME_VERSION standing in for a token that names none. It scopes
@@ -1501,7 +1517,7 @@ async function resolveRoomInstance(
 	// another, and neither must a session running a different version of the room.
 	// Private matchmakes always get a fresh instance. Create one when there's nothing
 	// to join.
-	let instance = isPrivate
+	let instance = privateInstance
 		? null
 		: await getJoinableInstance(c.env.DB, f.roomId, gameVersion, f.subRoomId, currentInstanceId)
 	if (!instance) {
@@ -1514,7 +1530,7 @@ async function resolveRoomInstance(
 			photonRoomId: crypto.randomUUID(),
 			name: f.name,
 			maxCapacity: f.maxCapacity,
-			isPrivate: isPrivate || f.isDorm,
+			isPrivate: privateInstance || f.isDorm,
 			roomInstanceType: f.roomInstanceType,
 			gameVersion,
 		})
@@ -1523,7 +1539,7 @@ async function resolveRoomInstance(
 		instance: roomInstanceFromRoom(
 			c.env,
 			room,
-			isPrivate,
+			privateInstance,
 			instance.roomInstanceId,
 			instance.photonRoomId,
 			f.subRoomId
@@ -1542,7 +1558,8 @@ async function resolveRoomInstance(
  * The one gate that is these routes' alone is the room's ACCESSIBILITY (see
  * {@link canEnterRoom}): a room that isn't published answers `RoomIsPrivate` (25) to anyone
  * but its creator, its role holders and its invitees, in either join mode — a private
- * instance of an unpublished room is still a way into it.
+ * instance of an unpublished room is still a way into it. Those it does admit always get
+ * a PRIVATE instance of it, whatever `JoinMode` they posted.
  *
  * `subRoomId` is optional: absent, `resolveRoomInstance` falls back to the room's first
  * subroom (its default entrance).
@@ -2317,6 +2334,21 @@ const app = new Hono<App>()
 				return matchmakeResult(c, BANNED_FROM_ROOM, null)
 			}
 
+			// Nor through the room's accessibility gate: friendship is not a key to a room its
+			// owner hasn't published, so the friend must be someone that room admits on their
+			// own account (canEnterRoom). The same opaque refusal as "not in a room" — a
+			// distinct code would tell the caller where their friend is. An instance naming no
+			// stored room (a dorm's synthetic one) has nothing to gate on.
+			const followedRoom = await getRoomById(c.env.DB, instance.roomId)
+			if (followedRoom && !(await canEnterRoom(c.env.DB, followedRoom, id))) {
+				logger.info('follow refused: friend is in an unpublished room', {
+					roomId: instance.roomId,
+					targetId,
+					id,
+				})
+				return matchmakeResult(c, NO_SUCH_ROOM, null)
+			}
+
 			// Nor does it go through the build scoping the room matchmakes get by
 			// construction, so a player on another build could otherwise follow their way
 			// into a session that can't render them. Compared against the FRIEND's presence

apps/match/src/test/integration/api.test.ts

@@ -3032,6 +3032,105 @@ describe('auth-gated endpoints', () => {
 		expect((await v2('/matchmake/v2/room/2', '9880', 2)).RoomInstance?.RoomId).toBe(2)
 	})
 
+	test('an unpublished room’s instances are always PRIVATE, whatever JoinMode asked for', async () => {
+		type V2 = {
+			ErrorCode: number
+			RoomInstance: { RoomInstanceId: number; RoomId: number; IsPrivate: boolean } | null
+		}
+		const v2 = async (path: string, sub: string, joinMode: number) =>
+			(await (
+				await exports.default.fetch(`${ORIGIN}${path}`, {
+					method: 'POST',
+					headers: { ...(await bearer(sub)), 'Content-Type': 'application/json' },
+					body: JSON.stringify({ JoinMode: joinMode }),
+				})
+			).json()) as V2
+		const stored = async (instanceId: number | undefined) =>
+			(
+				await env.DB.prepare('SELECT is_private FROM room_instance WHERE id = ?1')
+					.bind(instanceId ?? 0)
+					.first<{ is_private: number }>()
+			)?.is_private
+
+		// The creator walking through their own room's subroom door posts JoinMode 0 — the
+		// body the client was seen sending. Room 6 is Private, so the session is too: in the
+		// answer, and in the row every other route reads.
+		const own = await v2('/matchmake/v2/room/6/6', '42', 0)
+		expect(own.ErrorCode).toBe(0)
+		expect(own.RoomInstance).toMatchObject({ RoomId: 6, IsPrivate: true })
+		expect(await stored(own.RoomInstance?.RoomInstanceId)).toBe(1)
+		// The 2023 spelling, and JoinMode 1, are the same.
+		const v1 = (await (
+			await exports.default.fetch(`${ORIGIN}/matchmake/room/6`, {
+				method: 'POST',
+				headers: { ...(await bearer('42')), 'Content-Type': 'application/x-www-form-urlencoded' },
+				body: 'JoinMode=1',
+			})
+		).json()) as { roomInstance: { roomInstanceId: number; isPrivate: boolean } | null }
+		expect(v1.roomInstance?.isPrivate).toBe(true)
+		expect(await stored(v1.roomInstance?.roomInstanceId)).toBe(1)
+
+		// Nothing public to reuse: a role holder asking for a public session gets a private
+		// one of their own rather than joining the creator's.
+		const host = await v2('/matchmake/v2/room/6', '44', 0)
+		expect(host.RoomInstance?.IsPrivate).toBe(true)
+		expect(host.RoomInstance?.RoomInstanceId).not.toBe(v1.roomInstance?.roomInstanceId)
+		expect(
+			await env.DB.prepare(
+				'SELECT COUNT(*) AS n FROM room_instance WHERE room_id = 6 AND is_private = 0'
+			).first<{ n: number }>()
+		).toEqual({ n: 0 })
+
+		// A FRIEND of the creator is not one of the room's people: neither follow gets them
+		// in — the 2023 route by the room's gate, the v2 route because the session is private.
+		await env.DB.prepare(
+			'INSERT INTO relationship (requester_id, target_id, relationship_type) VALUES (42, 9885, 3)'
+		).run()
+		try {
+			const follow = (await (
+				await exports.default.fetch(`${ORIGIN}/matchmake/player/42`, {
+					method: 'POST',
+					headers: await bearer('9885'),
+				})
+			).json()) as { errorCode: number; roomInstance: unknown }
+			expect(follow).toEqual(refused(20))
+			const followV2 = (await (
+				await exports.default.fetch(`${ORIGIN}/matchmake/v2/player/42`, {
+					method: 'POST',
+					headers: { ...(await bearer('9885')), 'Content-Type': 'application/json' },
+					body: '{}',
+				})
+			).json()) as V2
+			expect(followV2.ErrorCode).not.toBe(0)
+			expect(followV2.RoomInstance).toBeNull()
+			expect(
+				await env.DB.prepare('SELECT 1 AS hit FROM presence WHERE account_id = 9885').first()
+			).toBeNull()
+
+			// One of the room's own people who is also a friend may follow: the room admits
+			// them itself. Here the creator follows the Host into the Host's session.
+			await env.DB.prepare(
+				'INSERT INTO relationship (requester_id, target_id, relationship_type) VALUES (42, 44, 3)'
+			).run()
+			const ownFollow = (await (
+				await exports.default.fetch(`${ORIGIN}/matchmake/player/44`, {
+					method: 'POST',
+					headers: await bearer('42'),
+				})
+			).json()) as { errorCode: number; roomInstance: { roomInstanceId: number } | null }
+			expect(ownFollow.errorCode).toBe(0)
+			expect(ownFollow.roomInstance?.roomInstanceId).toBe(host.RoomInstance?.RoomInstanceId)
+		} finally {
+			await env.DB.prepare(
+				'DELETE FROM relationship WHERE requester_id = 42 AND target_id IN (9885, 44)'
+			).run()
+		}
+
+		// A published room still hands out a public session for the same request.
+		const open = await v2('/matchmake/v2/room/2', '9885', 0)
+		expect(open.RoomInstance?.IsPrivate).toBe(false)
+	})
+
 	test('POST /matchmake/room/:roomId refuses a player banned from the room', async () => {
 		const matchmake = async (sub: string) =>
 			(await (