Don’t allow to change type of direct rooms. Add migration

Closes #5808

packages/rocketchat-channel-settings/server/functions/saveRoomType.coffee

@@ -3,7 +3,15 @@ RocketChat.saveRoomType = (rid, roomType, user, sendMessage=true) ->
 		throw new Meteor.Error 'invalid-room', 'Invalid room', { function: 'RocketChat.saveRoomType' }
 
 	if roomType not in ['c', 'p']
-		throw new Meteor.Error 'error-invalid-room-type', 'error-invalid-room-type', { type: roomType }
+		throw new Meteor.Error 'error-invalid-room-type', 'error-invalid-room-type', { function: 'RocketChat.saveRoomType', type: roomType }
+
+	room = RocketChat.models.Rooms.findOneById(rid);
+
+	if not room?
+		throw new Meteor.Error 'error-invalid-room', 'error-invalid-room', { function: 'RocketChat.saveRoomType', _id: rid }
+
+	if room.t is 'd'
+		throw new Meteor.Error 'error-direct-room', 'Can\'t change type of direct rooms', { function: 'RocketChat.saveRoomType' }
 
 	result = RocketChat.models.Rooms.setTypeById(rid, roomType) and RocketChat.models.Subscriptions.updateTypeByRoomId(rid, roomType)
 

server/startup/migrations/v085.js

+RocketChat.Migrations.add({
+	version: 85,
+	up() {
+		const query = {
+			t: 'p',
+			usernames: {$size: 2},
+			u: {$exists: false},
+			name: {$exists: false}
+		};
+
+		const rooms = RocketChat.models.Rooms.find(query).fetch();
+
+		if (rooms.length > 0) {
+			const rids = rooms.map(room => room._id);
+			RocketChat.models.Rooms.update({_id: {$in: rids}}, {$set: {t: 'd'}}, {multi: true});
+			RocketChat.models.Subscriptions.update({rid: {$in: rids}}, {$set: {t: 'd'}}, {multi: true});
+		}
+	}
+});