Merge branch '4.1'

* 4.1:
  [appveyor] fix
  [DI] Fix dumping some complex service graphs
  Revert "minor #28321 [Routing] Fixed the interface description of the url generator interface (Toflar)"
  Fixed caching of templates in default path on cache warmup
  added missing LICENSE file
  remove cache warmers when Twig cache is disabled
  [Workflow] Make sure we do not run the next transition on an updated state
  change baseUrl to basePath to fix wrong profiler url
  [HttpKernel][FrameworkBundle] Fix escaping of serialized payloads passed to test clients
  chore: rename Appveyor filename
  Fixed the interface description of the url generator interface
  Format file size in validation message according to binaryFormat option

Author: nicolas-grekas

Client.php

@@ -161,8 +161,8 @@ protected function doRequestInProcess($request)
      */
     protected function getScript($request)
     {
-        $kernel = str_replace("'", "\\'", serialize($this->kernel));
-        $request = str_replace("'", "\\'", serialize($request));
+        $kernel = var_export(serialize($this->kernel), true);
+        $request = var_export(serialize($request), true);
         $errorReporting = error_reporting();
 
         $requires = '';
@@ -171,7 +171,7 @@ protected function getScript($request)
                 $r = new \ReflectionClass($class);
                 $file = \dirname(\dirname($r->getFileName())).'/autoload.php';
                 if (file_exists($file)) {
-                    $requires .= "require_once '".str_replace("'", "\\'", $file)."';\n";
+                    $requires .= 'require_once '.var_export($file, true).";\n";
                 }
             }
         }
@@ -180,7 +180,7 @@ protected function getScript($request)
             throw new \RuntimeException('Composer autoloader not found.');
         }
 
-        $requires .= "require_once '".str_replace("'", "\\'", (new \ReflectionObject($this->kernel))->getFileName())."';\n";
+        $requires .= 'require_once '.var_export((new \ReflectionObject($this->kernel))->getFileName(), true).";\n";
 
         $profilerCode = '';
         if ($this->profiler) {
@@ -194,11 +194,11 @@ protected function getScript($request)
 
 $requires
 
-\$kernel = unserialize('$kernel');
+\$kernel = unserialize($kernel);
 \$kernel->boot();
 $profilerCode
 
-\$request = unserialize('$request');
+\$request = unserialize($request);
 EOF;
 
         return $code.$this->getHandleScript();