Fix styles not loaded when startup_css is enabled

On the Jira Connect app, custom CSS styles were not
loading. This was due to code related to startup_css.
We are using `add_page_specific_style` to include the CSS
which then calls `stylesheet_link_tag_defer`. When
`startup_css` is enabled, the stylesheet is included as
`media: print` which only applies the styles when page is
printed instead of applying them to "all" or "screen".

This change adds a param to the helper which allows us
to disable the `defer` behaviour when not needed and
use that in the jira_connect app.

I also update the order of includes in the jira_connect
layout to group stylesheets and javascripts properly.

app/helpers/application_helper.rb

@@ -361,9 +361,13 @@ module ApplicationHelper
     }
   end
 
-  def add_page_specific_style(path)
+  def add_page_specific_style(path, defer: true)
     content_for :page_specific_styles do
-      stylesheet_link_tag_defer path
+      if defer
+        stylesheet_link_tag_defer path
+      else
+        stylesheet_link_tag path
+      end
     end
   end
 

app/views/jira_connect/subscriptions/index.html.haml

@@ -63,4 +63,4 @@
 = webpack_bundle_tag 'jira_connect_app'
 
 = page_specific_javascript_tag('jira_connect.js')
-- add_page_specific_style 'page_bundles/jira_connect'
+- add_page_specific_style 'page_bundles/jira_connect', defer: false

app/views/layouts/jira_connect.html.haml

@@ -5,9 +5,10 @@
       GitLab
     = stylesheet_link_tag 'https://unpkg.com/@atlaskit/css-reset@3.0.6/dist/bundle.css'
     = stylesheet_link_tag 'https://unpkg.com/@atlaskit/reduced-ui-pack@10.5.5/dist/bundle.css'
+    = yield :page_specific_styles
+
     = javascript_include_tag 'https://connect-cdn.atl-paas.net/all.js'
     = javascript_include_tag 'https://unpkg.com/jquery@3.3.1/dist/jquery.min.js'
-    = yield :page_specific_styles
     = yield :head
   %body
     .ac-content

changelogs/unreleased/273777-fix-css-not-loading-on-jira-connect-app.yml

+---
+title: Fix Jira Connect styles not loaded when startup_css is enabled
+merge_request: 47043
+author:
+type: fixed