Fix infinite loop on NEW_CHATROOM_UNREAD_POSITION

frontend/controller/service-worker.js

@@ -211,12 +211,18 @@ sbp('sbp/selectors/register', {
 })
 
 // Events that need to be relayed to the SW
-;[LOGIN_COMPLETE, NEW_CHATROOM_UNREAD_POSITION, SET_APP_LOGS_FILTER].forEach((event) =>
+;[LOGIN_COMPLETE, SET_APP_LOGS_FILTER].forEach((event) =>
   sbp('okTurtles.events/on', event, (...data) => {
     navigator.serviceWorker.controller?.postMessage({ type: 'event', subtype: event, data })
   })
 )
 
+sbp('okTurtles.events/on', NEW_CHATROOM_UNREAD_POSITION, (obj: Object) => {
+  // Don't send messages from the SW back to the SW to prevent infinite loops
+  if (obj.from === 'sw') return
+  navigator.serviceWorker.controller?.postMessage({ type: 'event', subtype: event, data: [obj] })
+})
+
 const swRpc = (() => {
   if (!navigator.serviceWorker) {
     throw new Error('Missing service worker object')

frontend/controller/serviceworkers/sw-primary.js

@@ -87,7 +87,7 @@ sbp('okTurtles.events/on', CHELONIA_RESET, setupRootState)
   LOGIN_ERROR, LOGOUT, ACCEPTED_GROUP, CHATROOM_USER_STOP_TYPING,
   CHATROOM_USER_TYPING, DELETED_CHATROOM, LEFT_CHATROOM, LEFT_GROUP,
   JOINED_CHATROOM, JOINED_GROUP, KV_EVENT, MESSAGE_RECEIVE, MESSAGE_SEND,
-  NAMESPACE_REGISTRATION, NEW_CHATROOM_UNREAD_POSITION, NEW_LAST_LOGGED_IN,
+  NAMESPACE_REGISTRATION, NEW_LAST_LOGGED_IN,
   NEW_PREFERENCES, NEW_UNREAD_MESSAGES, NOTIFICATION_EMITTED,
   NOTIFICATION_REMOVED, NOTIFICATION_STATUS_LOADED, OFFLINE, ONLINE,
   PROPOSAL_ARCHIVED, SERIOUS_ERROR, SWITCH_GROUP
@@ -108,6 +108,26 @@ sbp('okTurtles.events/on', CHELONIA_RESET, setupRootState)
   })
 })
 
+// This event (`NEW_CHATROOM_UNREAD_POSITION`) requires special handling because
+// it can be sent from the SW to clients or from clients to the SW. Handling it
+// the normal way (in the forwarding logic above) would result in event loops.
+sbp('okTurtles.events/on', NEW_CHATROOM_UNREAD_POSITION, (args) => {
+  // Set a 'from' parameter to signal it comes from the SW
+  const argsCopy = { ...args, from: 'sw' }
+  const { data } = serializer(argsCopy)
+  const message = {
+    type: 'event',
+    subtype: NEW_CHATROOM_UNREAD_POSITION,
+    data
+  }
+  self.clients.matchAll()
+    .then((clientList) => {
+      clientList.forEach((client) => {
+        client.postMessage(message)
+      })
+    })
+})
+
 // Logs are treated especially to avoid spamming logs with event emitted
 // entries
 sbp('okTurtles.events/on', CAPTURED_LOGS, (...args) => {