Refactor to mark Changes tab as active on new MR page.

app/controllers/projects/application_controller.rb

@@ -83,6 +83,7 @@ class Projects::ApplicationController < ApplicationController
   end
 
   def apply_diff_view_cookie!
+    @show_changes_tab = params[:view].present?
     cookies.permanent[:diff_view] = params.delete(:view) if params[:view].present?
   end
 

app/controllers/projects/merge_requests_controller.rb

@@ -216,7 +216,6 @@ class Projects::MergeRequestsController < Projects::ApplicationController
     @base_commit = @merge_request.diff_base_commit
     @diffs = @merge_request.diffs(diff_options) if @merge_request.compare
     @diff_notes_disabled = true
-    @show_diff_tab = check_diff_tab
     @pipeline = @merge_request.pipeline
     @statuses = @pipeline.statuses.relevant if @pipeline
 
@@ -520,10 +519,4 @@ class Projects::MergeRequestsController < Projects::ApplicationController
     params[:merge_request] ||= ActionController::Parameters.new(source_project: @project)
     @merge_request = MergeRequests::BuildService.new(project, current_user, merge_request_params).execute
   end
-
-  private
-
-  def check_diff_tab
-    request.query_parameters[:view].present?
-  end
 end

app/views/projects/merge_requests/_new_submit.html.haml

@@ -54,6 +54,6 @@
   });
 :javascript
   var merge_request = new MergeRequest({
-    action: "#{(@show_diff_tab ? 'diffs' : 'new')}",
+    action: "#{(@show_changes_tab ? 'diffs' : 'new')}",
     setUrl: false
   });

spec/features/merge_requests/create_new_mr_spec.rb

 require 'spec_helper'
 
 feature 'Create New Merge Request', feature: true, js: true do
-  include WaitForAjax
-
   let(:user) { create(:user) }
   let(:project) { create(:project, :public) }
 
@@ -51,11 +49,10 @@ feature 'Create New Merge Request', feature: true, js: true do
 
     click_link 'Changes'
 
-    expect(page.find_link('Inline')[:class]).to match(/\bactive\b/)
-    expect(page.find_link('Side-by-side')[:class]).not_to match(/\bactive\b/)
+    expect(page).to have_css('a.btn.active', text: 'Inline')
+    expect(page).not_to have_css('a.btn.active', text: 'Side-by-side')
 
     click_link 'Side-by-side'
-    wait_for_ajax
 
     within '.merge-request' do
       expect(page).not_to have_css('a.btn.active', text: 'Inline')