fix: log error to prevent headers already sent

retry on uniq index fail

src/controllers/topics.js

@@ -3,6 +3,7 @@
 
 var async = require('async');
 var nconf = require('nconf');
+var winston = require('winston');
 
 var user = require('../user');
 var meta = require('../meta');
@@ -172,7 +173,7 @@ topicsController.get = function getTopic(req, res, callback) {
 			if (req.loggedIn) {
 				topics.markAsRead([tid], req.uid, function (err, markedRead) {
 					if (err) {
-						return callback(err);
+						return winston.error(err);
 					}
 					if (markedRead) {
 						topics.pushUnreadCount(req.uid);

src/database/mongo/sets.js

@@ -55,6 +55,9 @@ module.exports = function (db, module) {
 		}
 
 		bulk.execute(function (err) {
+			if (err && err.message.startsWith('E11000 duplicate key error')) {
+				return process.nextTick(module.setsAdd, keys, value, callback);
+			}
 			callback(err);
 		});
 	};