Merge branch '5.4' into 6.0

* 5.4:
  Add missing files from 5.3
  Remove unneeded files
  Tweak bug report template
  Prevent infinite nesting of lazy `ObjectManager` instances when `ObjectManager` is reset
  [DependencyInjection] Skip parameter attribute configurators in AttributeAutoconfigurationPass if we can't get the constructor reflector
  [HttpKernel] fix sending Vary: Accept-Language when appropriate

Author: fabpot

EventListener/LocaleListener.php

@@ -70,6 +70,7 @@ private function setLocale(Request $request)
             $request->setLocale($locale);
         } elseif ($this->useAcceptLanguageHeader && $this->enabledLocales && ($preferredLanguage = $request->getPreferredLanguage($this->enabledLocales))) {
             $request->setLocale($preferredLanguage);
+            $request->attributes->set('_vary_by_language', true);
         }
     }
 

EventListener/ResponseListener.php

@@ -50,6 +50,9 @@ public function onKernelResponse(ResponseEvent $event)
 
         if ($this->addContentLanguageHeader && !$response->isInformational() && !$response->isEmpty() && !$response->headers->has('Content-Language')) {
             $response->headers->set('Content-Language', $event->getRequest()->getLocale());
+        }
+
+        if ($event->getRequest()->attributes->get('_vary_by_language')) {
             $response->setVary('Accept-Language', false);
         }