Fix mention in edit mr

app/controllers/projects/merge_requests_controller.rb

@@ -330,6 +330,7 @@ class Projects::MergeRequestsController < Projects::MergeRequests::ApplicationCo
     @source_project = @merge_request.source_project
     @target_project = @merge_request.target_project
     @target_branches = @merge_request.target_project.repository.branch_names
+    @noteable = @merge_request
   end
 
   def finder_type

changelogs/unreleased/fix-mention-in-edit-mr.yml

+---
+title: Fixed mention autocomplete in edit merge request.
+merge_request:
+author:
+type: fixed

spec/controllers/projects/merge_requests_controller_spec.rb

@@ -885,4 +885,18 @@ describe Projects::MergeRequestsController do
       end
     end
   end
+
+  describe 'GET edit' do
+    it 'responds successfully' do
+      get :edit, namespace_id: project.namespace, project_id: project, id: merge_request
+
+      expect(response).to have_gitlab_http_status(:success)
+    end
+
+    it 'assigns the noteable to make sure autocompletes work' do
+      get :edit, namespace_id: project.namespace, project_id: project, id: merge_request
+
+      expect(assigns(:noteable)).not_to be_nil
+    end
+  end
 end

spec/support/shared_examples/features/editable_merge_request_shared_examples.rb

@@ -73,9 +73,13 @@ RSpec.shared_examples 'an editable merge request' do
 
   it 'description has autocomplete', :js do
     find('#merge_request_description').native.send_keys('')
-    fill_in 'merge_request_description', with: '@'
+    fill_in 'merge_request_description', with: user.to_reference[0..4]
 
-    expect(page).to have_selector('.atwho-view')
+    wait_for_requests
+
+    page.within('.atwho-view') do
+      expect(page).to have_content(user2.name)
+    end
   end
 
   it 'has class js-quick-submit in form' do