fixed #2704

src/controllers/groups.js

@@ -27,6 +27,8 @@ groupsController.list = function(req, res, next) {
 groupsController.details = function(req, res, next) {
 	var uid = req.user ? parseInt(req.user.uid, 10) : 0;
 
+	groups.existsBySlug(req.params.slug, function(err, exists) {
+		if (exists) {
 			async.parallel({
 				group: function(next) {
 					groups.getByGroupslug(req.params.slug, {
@@ -48,6 +50,10 @@ groupsController.details = function(req, res, next) {
 
 				res.render('groups/details', results);
 			});
+		} else {
+			return res.locals.isAPI ? res.status(302).json('/groups') : res.redirect('/groups');
+		}
+	});
 };
 
 groupsController.members = function(req, res, next) {

src/groups.js

@@ -422,6 +422,10 @@ var async = require('async'),
 		}
 	};
 
+	Groups.existsBySlug = function(slug, callback) {
+		db.isObjectField('groupslug:groupname', slug, callback);
+	};
+
 	Groups.create = function(data, callback) {
 		if (data.name.length === 0) {
 			return callback(new Error('[[error:group-name-too-short]]'));