Merge branch '4.4' into 5.4

* 4.4:
  Fix return type patching for list and class-string pseudo types
  [HttpKernel] [HttpCache] Don't throw on 304 Not Modified

Author: derrabus

HttpCache/AbstractSurrogate.php

@@ -95,7 +95,7 @@ public function handle(HttpCache $cache, string $uri, string $alt, bool $ignoreE
         try {
             $response = $cache->handle($subRequest, HttpKernelInterface::SUB_REQUEST, true);
 
-            if (!$response->isSuccessful()) {
+            if (!$response->isSuccessful() && Response::HTTP_NOT_MODIFIED !== $response->getStatusCode()) {
                 throw new \RuntimeException(sprintf('Error when rendering "%s" (Status code is %d).', $subRequest->getUri(), $response->getStatusCode()));
             }
 

Tests/HttpCache/EsiTest.php

@@ -221,6 +221,15 @@ public function testHandleWhenResponseIsNot200AndAltIsPresent()
         $this->assertEquals('bar', $esi->handle($cache, '/', '/alt', false));
     }
 
+    public function testHandleWhenResponseIsNotModified()
+    {
+        $esi = new Esi();
+        $response = new Response('');
+        $response->setStatusCode(304);
+        $cache = $this->getCache(Request::create('/'), $response);
+        $this->assertEquals('', $esi->handle($cache, '/', '/alt', true));
+    }
+
     protected function getCache($request, $response)
     {
         $cache = $this->getMockBuilder(HttpCache::class)->setMethods(['getRequest', 'handle'])->disableOriginalConstructor()->getMock();