Merge pull request #15656 from RocketChat/read-receipts-ignore-subscr…

…iptions-without-ls

[FIX] Read Receipts were not working properly with subscriptions without ls

app/models/server/models/Subscriptions.js

@@ -644,6 +644,9 @@ export class Subscriptions extends Base {
 	getMinimumLastSeenByRoomId(rid) {
 		return this.db.findOne({
 			rid,
+			ls: {
+				$exists: true,
+			},
 		}, {
 			sort: {
 				ls: 1,

imports/message-read-receipt/server/lib/ReadReceipt.js

@@ -19,6 +19,10 @@ const debounceByRoomId = function(fn) {
 const updateMessages = debounceByRoomId(Meteor.bindEnvironment(({ _id, lm }) => {
 	// @TODO maybe store firstSubscription in room object so we don't need to call the above update method
 	const firstSubscription = Subscriptions.getMinimumLastSeenByRoomId(_id);
+	if (!firstSubscription) {
+		return;
+	}
+
 	Messages.setAsRead(_id, firstSubscription.ls);
 
 	if (lm <= firstSubscription.ls) {
@@ -53,7 +57,7 @@ export const ReadReceipt = {
 
 		// this will usually happens if the message sender is the only one on the room
 		const firstSubscription = Subscriptions.getMinimumLastSeenByRoomId(roomId);
-		if (message.unread && message.ts < firstSubscription.ls) {
+		if (firstSubscription && message.unread && message.ts < firstSubscription.ls) {
 			Messages.setAsReadById(message._id, firstSubscription.ls);
 		}