From af3dc4e53736e87c198707dc74c85a77f305ef47 Mon Sep 17 00:00:00 2001
From: Guo Xiang Tan <tgx_world@hotmail.com>
Date: Fri, 2 Jun 2017 17:38:14 +0900
Subject: [PATCH] FIX: Publish group's categories to user when adding user to
 group.

https://meta.discourse.org/t/joining-a-group-doesnt-take-effect-unless-the-browser-is-hard-refreshed/57357/11?u=tgxworld
---
 app/models/group.rb       |  5 +++++
 spec/models/group_spec.rb | 17 +++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/app/models/group.rb b/app/models/group.rb
index 1c185cc7912..dc4de2d1338 100644
--- a/app/models/group.rb
+++ b/app/models/group.rb
@@ -371,6 +371,11 @@ class Group < ActiveRecord::Base
 
   def add(user)
     self.users.push(user) unless self.users.include?(user)
+
+    MessageBus.publish('/categories', {
+      categories: ActiveModel::ArraySerializer.new(self.categories).as_json
+    }, user_ids: [user.id])
+
     self
   end
 
diff --git a/spec/models/group_spec.rb b/spec/models/group_spec.rb
index c70426e04c9..1455f098157 100644
--- a/spec/models/group_spec.rb
+++ b/spec/models/group_spec.rb
@@ -3,6 +3,7 @@ require 'rails_helper'
 describe Group do
   let(:admin) { Fabricate(:admin) }
   let(:user) { Fabricate(:user) }
+  let(:group) { Fabricate(:group) }
 
   describe '#builtin' do
     context "verify enum sequence" do
@@ -450,4 +451,20 @@ describe Group do
       end
     end
   end
+
+  describe '#add' do
+    context 'when adding a user into a public group' do
+      let(:category) { Fabricate(:category) }
+
+      it "should publish the group's categories to the client" do
+        group.update!(public: true, categories: [category])
+
+        message = MessageBus.track_publish { group.add(user) }.first
+
+        expect(message.data[:categories].count).to eq(1)
+        expect(message.data[:categories].first[:id]).to eq(category.id)
+        expect(message.user_ids).to eq([user.id])
+      end
+    end
+  end
 end