changes from review

crates/core/src/host/host_controller.rs

@@ -534,7 +534,7 @@ async fn make_replica_ctx(
 ) -> anyhow::Result<ReplicaContext> {
     let logger = tokio::task::block_in_place(move || Arc::new(DatabaseLogger::open_today(path.module_logs())));
     let subscriptions = Arc::new(RwLock::new(SubscriptionManager::default()));
-    let manager = subscriptions.clone();
+    let downgraded = Arc::downgrade(&subscriptions);
     let subscriptions = ModuleSubscriptions::new(relational_db.clone(), subscriptions, database.owner_identity);
 
     // If an error occurs when evaluating a subscription,
@@ -543,7 +543,9 @@ async fn make_replica_ctx(
     tokio::spawn(async move {
         loop {
             tokio::time::sleep(Duration::from_secs(10)).await;
-            let subscriptions = manager.clone();
+            let Some(subscriptions) = downgraded.upgrade() else {
+                break;
+            };
             tokio::task::spawn_blocking(move || {
                 subscriptions.write().remove_dropped_clients();
             })

crates/core/src/subscription/module_subscription_manager.rs

@@ -222,12 +222,13 @@ impl SubscriptionManager {
     /// This will return an error if the client does not have a subscription with the given query id.
     pub fn remove_subscription(&mut self, client_id: ClientId, query_id: ClientQueryId) -> Result<Query, DBError> {
         let subscription_id = (client_id, query_id);
-        let Some(ci) = self.clients.get_mut(&client_id) else {
+        let Some(ci) = self
+            .clients
+            .get_mut(&client_id)
+            .filter(|ci| !ci.dropped.load(Ordering::Acquire))
+        else {
             return Err(anyhow::anyhow!("Client not found: {:?}", client_id).into());
         };
-        if ci.dropped.load(Ordering::Acquire) {
-            return Err(anyhow::anyhow!("Client not found: {:?}", client_id).into());
-        }
         let Some(query_hash) = ci.subscriptions.remove(&subscription_id) else {
             return Err(anyhow::anyhow!("Subscription not found: {:?}", subscription_id).into());
         };