From 99ab0ea2de2404e695ce3010aa2a0ce40c594710 Mon Sep 17 00:00:00 2001
From: Sawyer Cutler <sawyer@dirtroad.dev>
Date: Sun, 30 Aug 2026 04:59:36 -0700
Subject: [PATCH 1/2] Add tests for doc/snapshot-listener-only rooms surviving
 teardown

destroyRoomIfEmpty's emptiness check only looks at clientIdByPrincipal
and listeners, so a room kept alive only by a subscribeDocUpdates or
subscribeSnapshots listener is destroyed and silently recreated on the
next empty join/leave cycle, permanently orphaning that listener.
---
 packages/presence/src/room-registry.test.ts | 38 +++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/packages/presence/src/room-registry.test.ts b/packages/presence/src/room-registry.test.ts
index 41f7ea96f..fc7609671 100644
--- a/packages/presence/src/room-registry.test.ts
+++ b/packages/presence/src/room-registry.test.ts
@@ -315,6 +315,44 @@ describe("createPresenceRoomRegistry: doc sync", () => {
 
     expect(seen).toEqual([]);
   });
+
+  test("a room kept alive only by a doc-update listener survives an otherwise-empty join/leave cycle", () => {
+    const registry = createPresenceRoomRegistry();
+    const docUpdates: string[] = [];
+    registry.subscribeDocUpdates(docKey, (_update, author) =>
+      docUpdates.push(author),
+    );
+
+    registry.join(docKey, state("prn_alice"));
+    registry.leave(docKey, "prn_alice"); // no presence `subscribe` listener attached
+
+    // The room must still be alive — proven by a doc update still
+    // reaching the listener registered before the join/leave cycle,
+    // rather than the room having been silently torn down and recreated
+    // out from under it.
+    const alice = clientDoc();
+    alice.getText("content").insert(0, "still here");
+    registry.applyDocUpdate(docKey, Y.encodeStateAsUpdate(alice), "prn_alice2");
+
+    expect(docUpdates).toEqual(["prn_alice2"]);
+  });
+
+  test("a room kept alive only by a snapshot listener survives an otherwise-empty join/leave cycle", () => {
+    const registry = createPresenceRoomRegistry();
+    const notifications: number[] = [];
+    registry.subscribeSnapshots(docKey, (info) =>
+      notifications.push(info.version),
+    );
+
+    registry.join(docKey, state("prn_alice"));
+    registry.leave(docKey, "prn_alice");
+
+    // Proven the same way: the room surviving is what lets a later
+    // `notifySnapshot` still reach the listener.
+    registry.notifySnapshot(docKey, { version: 7, savedAt: 1 });
+
+    expect(notifications).toEqual([7]);
+  });
 });
 
 describe("createPresenceRoomRegistry: deferred destroy", () => {

From a9adb98da43bc493acc1ead6efd5e4e80d4631b9 Mon Sep 17 00:00:00 2001
From: Sawyer Cutler <sawyer@dirtroad.dev>
Date: Sun, 30 Aug 2026 04:59:46 -0700
Subject: [PATCH 2/2] Count doc/snapshot listeners toward a room's emptiness

destroyRoomIfEmpty now treats a room as non-empty while it still has a
subscribeDocUpdates or subscribeSnapshots listener, not just presence
members and subscribe() listeners, and both of those subscriptions'
teardown paths now attempt cleanup themselves so a room kept alive only
by one of them still gets torn down once that listener goes away.
---
 packages/presence/src/room-registry.ts | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/packages/presence/src/room-registry.ts b/packages/presence/src/room-registry.ts
index 2775936c1..8af84096b 100644
--- a/packages/presence/src/room-registry.ts
+++ b/packages/presence/src/room-registry.ts
@@ -277,7 +277,12 @@ export function createPresenceRoomRegistry(): PresenceRoomRegistry {
   }
 
   function isRoomEmpty(room: Room): boolean {
-    return room.clientIdByPrincipal.size === 0 && room.listeners.size === 0;
+    return (
+      room.clientIdByPrincipal.size === 0 &&
+      room.listeners.size === 0 &&
+      room.docListeners.size === 0 &&
+      room.snapshotListeners.size === 0
+    );
   }
 
   function destroyRoomIfEmpty(key: PresenceRoomKey, room: Room): void {
@@ -443,6 +448,7 @@ export function createPresenceRoomRegistry(): PresenceRoomRegistry {
       room.docListeners.add(listener);
       return () => {
         room.docListeners.delete(listener);
+        destroyRoomIfEmpty(key, room);
       };
     },
 
@@ -471,6 +477,7 @@ export function createPresenceRoomRegistry(): PresenceRoomRegistry {
       room.snapshotListeners.add(listener);
       return () => {
         room.snapshotListeners.delete(listener);
+        destroyRoomIfEmpty(key, room);
       };
     },
   };