[HttpKernel] Account for Response::getDate() possibly returning a DateTimeImmutable

Author: nicolas-grekas

HttpCache/ResponseCacheStrategy.php

@@ -147,7 +147,7 @@ public function update(Response $response)
 
         if (is_numeric($this->ageDirectives['expires'])) {
             $date = clone $response->getDate();
-            $date->modify('+'.($this->ageDirectives['expires'] + $this->age).' seconds');
+            $date = $date->modify('+'.($this->ageDirectives['expires'] + $this->age).' seconds');
             $response->setExpires($date);
         }
     }

Tests/HttpCache/ResponseCacheStrategyTest.php

@@ -257,7 +257,7 @@ public function testCacheControlMerging(array $expects, array $master, array $su
 
                     case 'expires':
                         $expires = clone $response->getDate();
-                        $expires->modify('+'.$value.' seconds');
+                        $expires = $expires->modify('+'.$value.' seconds');
                         $response->setExpires($expires);
                         break;