fix: client trying to subscribe to streams before completing the login process

.changeset/cold-mangos-impress.md

@@ -0,0 +1,5 @@
+---
+'@rocket.chat/meteor': patch
+---
+
+Fixed an issue that caused clients to not properly receive certain server notifications right after login

apps/meteor/client/meteorOverrides/ddpOverREST.ts

@@ -57,13 +57,35 @@ const withDDPOverREST = (_send: (this: Meteor.IMeteorConnection, message: Meteor
 		sdk.rest
 			.post(`/v1/${endpoint}/${method}`, restParams)
 			.then(({ message: _message }) => {
-				processResult(_message);
+				// Calling Meteor.loginWithToken before processing the result of the first login will ensure that the new login request
+				// is added to the top of the list of methodInvokers.
+				// The request itself will only be sent after the first login result is processed, but
+				// the Accounts.onLogin callbacks will be called before this request is effectively sent;
+				// This way, any requests done inside of onLogin callbacks will be added to the list
+				// and processed only after the Meteor.loginWithToken request is done
+				// So, the effective order is:
+				//   1. regular login with password is sent
+				//   2. result of the password login is received
+				//   3. login with token is added to the list of pending requests
+				//   4. result of the password login is processed
+				//   5. Accounts.onLogin callbacks are triggered, Meteor.userId is set
+				//   6. the request for the login with token is effectively sent
+				//   7. login with token result is processed
+				//   8. requests initiated inside of the Accounts.onLogin callback are then finally sent
+				//
+				// Keep in mind that there's a difference in how meteor3 processes the request results, compared to older meteor versions
+				// On meteor3, any collection writes triggered by a request result are done async, which means that the `processResult` call
+				// will not immediatelly trigger the callbacks, like it used to in older versions.
+				// That means that on meteor3+, it doesn't really make a difference if processResult is called before or after the Meteor.loginWithToken here
+				// as the result will be processed async, the loginWithToken call will be initiated before it is effectively processed anyway.
 				if (message.method === 'login') {
 					const parsedMessage = DDPCommon.parseDDP(_message) as { result?: { token?: string } };
 					if (parsedMessage.result?.token) {
 						Meteor.loginWithToken(parsedMessage.result.token);
 					}
 				}
+
+				processResult(_message);
 			})
 			.catch((error) => {
 				console.error(error);