Merge branch '5.4' into 6.3

* 5.4:
  [FrameworkBundle] Update docblock AbstractController
  [HttpFoundation][FrameworkBundle] Fix default locale is ignored when set_locale_from_accept_language is used
  add missing translations
  [Validator] updated Lithuanian translation
  [Validator] fix some non-sense Lithuanian translations
  [Validator] updated Slovenian translation
  [Validator] updated Finnish translation
  [Validator] Add `Charset` french translation
  [Tests] Streamline CompiledUrlGenerator tests
  [Serializer] Skip uninitialized properties with deep_object_to_populate
  fix Constraints\Email::ERROR_NAMES

Author: nicolas-grekas

EventListener/LocaleListener.php

@@ -69,7 +69,7 @@ private function setLocale(Request $request): void
         if ($locale = $request->attributes->get('_locale')) {
             $request->setLocale($locale);
         } elseif ($this->useAcceptLanguageHeader) {
-            if ($preferredLanguage = $request->getPreferredLanguage($this->enabledLocales)) {
+            if ($request->getLanguages() && $preferredLanguage = $request->getPreferredLanguage($this->enabledLocales)) {
                 $request->setLocale($preferredLanguage);
             }
             $request->attributes->set('_vary_by_language', true);

Tests/EventListener/LocaleListenerTest.php

@@ -130,6 +130,28 @@ public function testRequestPreferredLocaleFromAcceptLanguageHeader()
         $this->assertEquals('fr', $request->getLocale());
     }
 
+    public function testRequestDefaultLocaleIfNoAcceptLanguageHeaderIsPresent()
+    {
+        $request = new Request();
+        $listener = new LocaleListener($this->requestStack, 'de', null, true, ['lt', 'de']);
+        $event = $this->getEvent($request);
+
+        $listener->setDefaultLocale($event);
+        $listener->onKernelRequest($event);
+        $this->assertEquals('de', $request->getLocale());
+    }
+
+    public function testRequestVaryByLanguageAttributeIsSetIfUsingAcceptLanguageHeader()
+    {
+        $request = new Request();
+        $listener = new LocaleListener($this->requestStack, 'de', null, true, ['lt', 'de']);
+        $event = $this->getEvent($request);
+
+        $listener->setDefaultLocale($event);
+        $listener->onKernelRequest($event);
+        $this->assertTrue($request->attributes->get('_vary_by_language'));
+    }
+
     public function testRequestSecondPreferredLocaleFromAcceptLanguageHeader()
     {
         $request = Request::create('/');