Merge branch 'cs-async-branch-dropdown' into 'master'

Load branch dropdowns asynchronously for cherry pick and revert dialogs

## Why was this MR needed and what does it do?

Previously every commit page was loading every branch onto the page twice, once each for the Cherry Pick and Revert modal dialogs. Most of the time they're never used, so that's a bit of a waste.

This loads them asynchronously by modifying the existing ref switcher code to also work for the branch selectors. This is better for performance.

## Are there points in the code the reviewer needs to double check?

Make sure Cherry Picking and Reverting still work (from my tests they seem to be fine).

## What are the relevant issue numbers?

Fixes #20108.

## Screenshots (if relevant)

Before:

![Screen_Shot_2016-08-01_at_4.35.21_PM](/uploads/6b76ea656fd00df52ab56df5309976dc/Screen_Shot_2016-08-01_at_4.35.21_PM.png)

![Screen_Shot_2016-08-01_at_4.35.52_PM](/uploads/d2699a4bfc4ad1a4d414429e7c50e60f/Screen_Shot_2016-08-01_at_4.35.52_PM.png)

After:

![Screen_Shot_2016-08-01_at_4.32.49_PM](/uploads/5faa6494b10dd9ac5e8850763a0c4018/Screen_Shot_2016-08-01_at_4.32.49_PM.png)

![Screen_Shot_2016-08-01_at_4.32.56_PM](/uploads/87c490bb375244e7d72421fd55e13e3f/Screen_Shot_2016-08-01_at_4.32.56_PM.png)

![Screen_Shot_2016-08-01_at_4.33.02_PM](/uploads/59ae65c0afc39d8939a9f36431815854/Screen_Shot_2016-08-01_at_4.33.02_PM.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [x] Added for this feature/bug
  - [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)

cc: @iamphill @jschatz1 

See merge request !5607

2 files changed, 27 insertions, 6 deletions

diff --git a/spec/features/projects/branches_spec.rb b/spec/features/projects/branches_spec.rb
index 79abba21854..1b14945bf0a 100644
--- a/spec/features/projects/branches_spec.rb
+++ b/spec/features/projects/branches_spec.rb
@@ -20,7 +20,7 @@ describe 'Branches', feature: true do
 
   describe 'Find branches' do
     it 'shows filtered branches', js: true do
-      visit namespace_project_branches_path(project.namespace, project, project.id)
+      visit namespace_project_branches_path(project.namespace, project)
 
       fill_in 'branch-search', with: 'fix'
       find('#branch-search').native.send_keys(:enter)
diff --git a/spec/features/projects/commits/cherry_pick_spec.rb b/spec/features/projects/commits/cherry_pick_spec.rb
index 1b4ff6b6f1b..e45e3a36d01 100644
--- a/spec/features/projects/commits/cherry_pick_spec.rb
+++ b/spec/features/projects/commits/cherry_pick_spec.rb
@@ -1,4 +1,5 @@
 require 'spec_helper'
+include WaitForAjax
 
 describe 'Cherry-pick Commits' do
   let(:project) { create(:project) }
@@ -8,12 +9,11 @@ describe 'Cherry-pick Commits' do
   before do
     login_as :user
     project.team << [@user, :master]
-    visit namespace_project_commits_path(project.namespace, project, project.repository.root_ref, { limit: 5 })
+    visit namespace_project_commit_path(project.namespace, project, master_pickable_commit.id)
   end
 
   context "I cherry-pick a commit" do
     it do
-      visit namespace_project_commit_path(project.namespace, project, master_pickable_commit.id)
       find("a[href='#modal-cherry-pick-commit']").click
       expect(page).not_to have_content('v1.0.0') # Only branches, not tags
       page.within('#modal-cherry-pick-commit') do
@@ -26,7 +26,6 @@ describe 'Cherry-pick Commits' do
 
   context "I cherry-pick a merge commit" do
     it do
-      visit namespace_project_commit_path(project.namespace, project, master_pickable_merge.id)
       find("a[href='#modal-cherry-pick-commit']").click
       page.within('#modal-cherry-pick-commit') do
         uncheck 'create_merge_request'
@@ -38,7 +37,6 @@ describe 'Cherry-pick Commits' do
 
   context "I cherry-pick a commit that was previously cherry-picked" do
     it do
-      visit namespace_project_commit_path(project.namespace, project, master_pickable_commit.id)
       find("a[href='#modal-cherry-pick-commit']").click
       page.within('#modal-cherry-pick-commit') do
         uncheck 'create_merge_request'
@@ -56,7 +54,6 @@ describe 'Cherry-pick Commits' do
 
   context "I cherry-pick a commit in a new merge request" do
     it do
-      visit namespace_project_commit_path(project.namespace, project, master_pickable_commit.id)
       find("a[href='#modal-cherry-pick-commit']").click
       page.within('#modal-cherry-pick-commit') do
         click_button 'Cherry-pick'
@@ -64,4 +61,28 @@ describe 'Cherry-pick Commits' do
       expect(page).to have_content('The commit has been successfully cherry-picked. You can now submit a merge request to get this change into the original branch.')
     end
   end
+
+  context "I cherry-pick a commit from a different branch", js: true do
+    it do
+      find('.commit-action-buttons a.dropdown-toggle').click
+      find(:css, "a[href='#modal-cherry-pick-commit']").click
+
+      page.within('#modal-cherry-pick-commit') do
+        click_button 'master'
+      end
+
+      wait_for_ajax
+
+      page.within('#modal-cherry-pick-commit .dropdown-menu .dropdown-content') do
+        click_link 'feature'
+      end
+
+      page.within('#modal-cherry-pick-commit') do
+        uncheck 'create_merge_request'
+        click_button 'Cherry-pick'
+      end
+
+      expect(page).to have_content('The commit has been successfully cherry-picked.')
+    end
+  end
 end