Correctly loads gfm autocomplete source on pages where it is required

CHANGELOG

@@ -57,6 +57,8 @@ v 8.12.0 (unreleased)
   - Optimistic locking for Issues and Merge Requests (title and description overriding prevention)
   - Add `wiki_page_events` to project hook APIs (Ben Boeckel)
   - Remove Gitorious import
+  - Loads GFM autocomplete source only when required
+  - Fix issue with slash commands not loading on new issue page
   - Fix inconsistent background color for filter input field (ClemMakesApps)
   - Remove prefixes from transition CSS property (ClemMakesApps)
   - Add Sentry logging to API calls

app/views/layouts/_init_auto_complete.html.haml

 - project = @target_project || @project
 - noteable_type = @noteable.class if @noteable.present?
 
-- if noteable_type
-  :javascript
-    GitLab.GfmAutoComplete.dataLoading = false;
-
 :javascript
   GitLab.GfmAutoComplete.dataSource = "#{autocomplete_sources_namespace_project_path(project.namespace, project, type: noteable_type, type_id: params[:id])}"
   GitLab.GfmAutoComplete.cachedData = undefined;

app/views/layouts/application.html.haml

@@ -10,4 +10,5 @@
     = render "layouts/header/default", title: header_title
     = render 'layouts/page', sidebar: sidebar, nav: nav
 
+    = render "layouts/init_auto_complete" if current_user && @load_gfm
     = yield :scripts_body

app/views/layouts/project.html.haml

@@ -14,9 +14,6 @@
       window.project_uploads_path = "#{namespace_project_uploads_path project.namespace,project}";
       window.preview_markdown_path = "#{preview_markdown_path}";
 
-- content_for :scripts_body do
-  = render "layouts/init_auto_complete" if current_user
-
 - content_for :header_content do
   .js-dropdown-menu-projects
     .dropdown-menu.dropdown-select.dropdown-menu-projects

app/views/projects/_zen.html.haml

+- @load_gfm = true
 - supports_slash_commands = local_assigns.fetch(:supports_slash_commands, false)
 .zen-backdrop
   - classes << ' js-gfm-input js-autosize markdown-area'

spec/features/projects/gfm_autocomplete_load_spec.rb

+require 'spec_helper'
+
+describe 'GFM autocomplete loading', feature: true, js: true do
+  let(:user)      { create(:user) }
+  let(:project)   { create(:project) }
+
+  before do
+    project.team << [user, :master]
+    login_as user
+
+    visit namespace_project_path(project.namespace, project)
+  end
+
+  it 'does not load on project#show' do
+    expect(evaluate_script('GitLab.GfmAutoComplete.dataSource')).to eq('')
+  end
+
+  it 'loads on new issue page' do
+    visit new_namespace_project_issue_path(project.namespace, project)
+
+    expect(evaluate_script('GitLab.GfmAutoComplete.dataSource')).not_to eq('')
+  end
+end