Merge branch '5.4' into 6.4

* 5.4:
  Update serializer.rst
  [HttpClient] Fix how cookies are defined and sent

Author: javiereguiluz

components/serializer.rst

@@ -752,7 +752,7 @@ When serializing, you can set a callback to format a specific object property::
 
     // all callback parameters are optional (you can omit the ones you don't use)
     $dateCallback = function (object $innerObject, object $outerObject, string $attributeName, ?string $format = null, array $context = []): string {
-        return $innerObject instanceof \DateTime ? $innerObject->format(\DateTime::ISO8601) : '';
+        return $innerObject instanceof \DateTime ? $innerObject->format(\DateTime::ATOM) : '';
     };
 
     $defaultContext = [

http_client.rst

@@ -686,17 +686,21 @@ cookies automatically.
 
 You can either :ref:`send cookies with the BrowserKit component <component-browserkit-sending-cookies>`,
 which integrates seamlessly with the HttpClient component, or manually setting
-the ``Cookie`` HTTP header as follows::
+`the Cookie HTTP request header`_ as follows::
 
     use Symfony\Component\HttpClient\HttpClient;
     use Symfony\Component\HttpFoundation\Cookie;
 
     $client = HttpClient::create([
         'headers' => [
-            'Cookie' => new Cookie('flavor', 'chocolate', strtotime('+1 day')),
+            // set one cookie as a name=value pair
+            'Cookie' => 'flavor=chocolate',
 
-            // you can also pass the cookie contents as a string
-            'Cookie' => 'flavor=chocolate; expires=Sat, 11 Feb 2023 12:18:13 GMT; Max-Age=86400; path=/'
+            // you can set multiple cookies at once separating them with a ;
+            'Cookie' => 'flavor=chocolate; size=medium',
+
+            // if needed, encode the cookie value to ensure that it contains valid characters
+            'Cookie' => sprintf("%s=%s", 'foo', rawurlencode('...')),
         ],
     ]);
 
@@ -2337,3 +2341,4 @@ you to do so, by yielding the exception from its body::
 .. _`SSRF`: https://portswigger.net/web-security/ssrf
 .. _`RFC 6570`: https://www.rfc-editor.org/rfc/rfc6570
 .. _`HAR`: https://w3c.github.io/web-performance/specs/HAR/Overview.html
+.. _`the Cookie HTTP request header`: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cookie