Merge branch 'fix-already-selected-activity-link' into 'master'

Fix inconsistent highlighting of already selected activity nav-links

## What does this MR do?

*  Remove edge case where user could deselect an activity nav-link (which seems to be returning all the events)
*  Explicitly add an `All` tab to return all the events

## Are there points in the code the reviewer needs to double check?
Shouldn't be

## Why was this MR needed?
Resolves existing UI inconsistency

## Screenshots (if relevant)
Before:
![4OzkoQVJYc](/uploads/fd2a7fdbde2159e875482ec7b828fe60/4OzkoQVJYc.gif)

After:
![E0lj8UhEUU](/uploads/7eb5155861eb79d72957de04c9f172c9/E0lj8UhEUU.gif)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

*  Closes #21631
*  Closes #21452


See merge request !6091

3 files changed, 8 insertions, 8 deletions

diff --git a/app/assets/javascripts/activities.js b/app/assets/javascripts/activities.js
index d5e11e22be5..f4f8cf04184 100644
--- a/app/assets/javascripts/activities.js
+++ b/app/assets/javascripts/activities.js
@@ -21,16 +21,14 @@
     };
 
     Activities.prototype.toggleFilter = function(sender) {
-      var event_filters, filter;
+      var filter = sender.attr("id").split("_")[0];
+
       $('.event-filter .active').removeClass("active");
-      event_filters = $.cookie("event_filter");
-      filter = sender.attr("id").split("_")[0];
-      $.cookie("event_filter", (event_filters !== filter ? filter : ""), {
+      $.cookie("event_filter", filter, {
         path: gon.relative_url_root || '/'
       });
-      if (event_filters !== filter) {
-        return sender.closest('li').toggleClass("active");
-      }
+
+      sender.closest('li').toggleClass("active");
     };
 
     return Activities;
diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index bd4ba384b29..b3455e04c29 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -173,7 +173,8 @@ class ApplicationController < ActionController::Base
   end
 
   def event_filter
-    filters = cookies['event_filter'].split(',') if cookies['event_filter'].present?
+    # Split using comma to maintain backward compatibility Ex/ "filter1,filter2"
+    filters = cookies['event_filter'].split(',')[0] if cookies['event_filter'].present?
     @event_filter ||= EventFilter.new(filters)
   end
 
diff --git a/app/views/shared/_event_filter.html.haml b/app/views/shared/_event_filter.html.haml
index 8824bcc158e..3480800369a 100644
--- a/app/views/shared/_event_filter.html.haml
+++ b/app/views/shared/_event_filter.html.haml
@@ -1,4 +1,5 @@
 %ul.nav-links.event-filter.scrolling-tabs
+  = event_filter_link EventFilter.all, 'All'
   = event_filter_link EventFilter.push, 'Push events'
   = event_filter_link EventFilter.merged, 'Merge events'
   = event_filter_link EventFilter.comments, 'Comments'