Fix Vary headers not being set on some redirects (#27272)

app/controllers/concerns/web_app_controller_concern.rb

@@ -4,10 +4,10 @@ module WebAppControllerConcern
   extend ActiveSupport::Concern
 
   included do
-    prepend_before_action :redirect_unauthenticated_to_permalinks!
-    before_action :set_app_body_class
-
     vary_by 'Accept, Accept-Language, Cookie'
+
+    before_action :redirect_unauthenticated_to_permalinks!
+    before_action :set_app_body_class
   end
 
   def skip_csrf_meta_tags?
@@ -22,7 +22,9 @@ module WebAppControllerConcern
     return if user_signed_in? && current_account.moved_to_account_id.nil?
 
     redirect_path = PermalinkRedirector.new(request.path).redirect_path
+    return if redirect_path.blank?
 
-    redirect_to(redirect_path) if redirect_path.present?
+    expires_in(15.seconds, public: true, stale_while_revalidate: 30.seconds, stale_if_error: 1.day) unless user_signed_in?
+    redirect_to(redirect_path)
   end
 end

app/controllers/follower_accounts_controller.rb

@@ -3,7 +3,6 @@
 class FollowerAccountsController < ApplicationController
   include AccountControllerConcern
   include SignatureVerification
-  include WebAppControllerConcern
 
   vary_by -> { public_fetch_mode? ? 'Accept, Accept-Language, Cookie' : 'Accept, Accept-Language, Cookie, Signature' }
 

app/controllers/following_accounts_controller.rb

@@ -3,7 +3,6 @@
 class FollowingAccountsController < ApplicationController
   include AccountControllerConcern
   include SignatureVerification
-  include WebAppControllerConcern
 
   vary_by -> { public_fetch_mode? ? 'Accept, Accept-Language, Cookie' : 'Accept, Accept-Language, Cookie, Signature' }
 

spec/requests/cache_spec.rb

@@ -30,6 +30,7 @@ module TestEndpoints
     /directory
     /@alice
     /@alice/110224538612341312
+    /deck/home
   ).freeze
 
   # Endpoints that should be cachable when accessed anonymously but have a Vary