Be explicit on merge request discussion variables

CHANGELOG

@@ -56,6 +56,7 @@ v 8.10.0 (unreleased)
   - Add API endpoint for a group issues !4520 (mahcsig)
   - Add Bugzilla integration !4930 (iamtjg)
   - Instrument Rinku usage
+  - Be explicit to define merge request discussion variables
   - Metrics for Rouge::Plugins::Redcarpet and Rouge::Formatters::HTMLGitlab
   - RailsCache metris now includes fetch_hit/fetch_miss and read_hit/read_miss info.
   - Allow [ci skip] to be in any case and allow [skip ci]. !4785 (simon_w)

app/controllers/projects/merge_requests_controller.rb

@@ -56,7 +56,7 @@ class Projects::MergeRequestsController < Projects::ApplicationController
 
   def show
     respond_to do |format|
-      format.html
+      format.html { define_discussion_vars }
 
       format.json do
         render json: @merge_request
@@ -82,7 +82,7 @@ class Projects::MergeRequestsController < Projects::ApplicationController
     @merge_request_diff = @merge_request.merge_request_diff
 
     respond_to do |format|
-      format.html
+      format.html { define_discussion_vars }
       format.json { render json: { html: view_to_html_string("projects/merge_requests/show/_diffs") } }
     end
   end
@@ -108,7 +108,11 @@ class Projects::MergeRequestsController < Projects::ApplicationController
 
   def commits
     respond_to do |format|
-      format.html { render 'show' }
+      format.html do
+        define_discussion_vars
+
+        render 'show'
+      end
       format.json do
         # Get commits from repository
         # or from cache if already merged
@@ -123,7 +127,11 @@ class Projects::MergeRequestsController < Projects::ApplicationController
 
   def builds
     respond_to do |format|
-      format.html { render 'show' }
+      format.html do
+        define_discussion_vars
+
+        render 'show'
+      end
       format.json { render json: { html: view_to_html_string('projects/merge_requests/show/_builds') } }
     end
   end
@@ -353,14 +361,11 @@ class Projects::MergeRequestsController < Projects::ApplicationController
       @merge_request.unlock_mr
       @merge_request.close
     end
-
-    if request.format == :html || action_name == 'show'
-      define_show_html_vars
-    end
   end
 
-  # Discussion tab data is only required on html requests
-  def define_show_html_vars
+  # Discussion tab data is rendered on html responses of actions
+  # :show, :diff, :commits, :builds. but not when request the data through AJAX
+  def define_discussion_vars
     # Build a note object for comment form
     @note = @project.notes.new(noteable: @noteable)
 

spec/features/merge_requests/diffs_spec.rb

+require 'spec_helper'
+
+feature 'Diffs URL', js: true, feature: true do
+  before do
+    login_as :admin
+    @merge_request = create(:merge_request)
+    @project = @merge_request.source_project
+  end
+
+  context 'when visit with */* as accept header' do
+    before(:each) do
+      page.driver.add_header('Accept', '*/*')
+    end
+
+    it 'renders the notes' do
+      create :note_on_merge_request, project: @project, noteable: @merge_request, note: 'Rebasing with master'
+
+      visit diffs_namespace_project_merge_request_path(@project.namespace, @project, @merge_request)
+
+      # Load notes and diff through AJAX
+      expect(page).to have_css('.note-text', visible: false, text: 'Rebasing with master')
+      expect(page).to have_css('.diffs.tab-pane.active')
+    end
+  end
+end