Merge branch '4.3' into 4.4

* 4.3:
  [Config] Disable default alphabet sorting in glob function due of unstable sort
  [HttpClient] always return the empty string when the response cannot have a body
  [TwigBundle][exception] Added missing css variable to highlight line in trace
  [Serializer] Improve messages for unexpected resources values
  [SecurityBundle] correct types for default arguments for firewall configs

Author: nicolas-grekas

Response/ResponseTrait.php

@@ -117,11 +117,15 @@ public function getContent(bool $throw = true): string
                 }
             }
 
-            if (null === $content) {
-                throw new TransportException('Cannot get the content of the response twice: buffering is disabled.');
+            if (null !== $content) {
+                return $content;
             }
 
-            return $content;
+            if ('HEAD' === $this->info['http_method'] || \in_array($this->info['http_code'], [204, 304], true)) {
+                return '';
+            }
+
+            throw new TransportException('Cannot get the content of the response twice: buffering is disabled.');
         }
 
         foreach (self::stream([$this]) as $chunk) {

Tests/HttpClientTestCase.php

@@ -75,34 +75,4 @@ public function testToStream404()
         $response = $client->request('GET', 'http://localhost:8057/404');
         $stream = $response->toStream();
     }
-
-    public function testInfoOnCanceledResponse()
-    {
-        $this->markTestSkipped('Implemented as of version 4.4');
-    }
-
-    public function testBufferSink()
-    {
-        $this->markTestSkipped('Implemented as of version 4.4');
-    }
-
-    public function testConditionalBuffering()
-    {
-        $this->markTestSkipped('Implemented as of version 4.4');
-    }
-
-    public function testReentrantBufferCallback()
-    {
-        $this->markTestSkipped('Implemented as of version 4.4');
-    }
-
-    public function testThrowingBufferCallback()
-    {
-        $this->markTestSkipped('Implemented as of version 4.4');
-    }
-
-    public function testMaxDuration()
-    {
-        $this->markTestSkipped('Implemented as of version 4.4');
-    }
 }