Merge branch '2.8' into 3.0

* 2.8:
  [TwigBundle] Removed redundant return statement.
  [DependencyInjection] Fixed deprecated default message template with XML
  [TwigBridge] Removed extra arguments in 2 places.
  [Process] Fix write access check for pipes on Windows
  [HttpKernel] Use flock() for HttpCache's lock files

Author: nicolas-grekas

Loader/XmlFileLoader.php

@@ -164,7 +164,7 @@ private function parseDefinition(\DOMElement $service, $file)
         }
 
         if ($deprecated = $this->getChildren($service, 'deprecated')) {
-            $definition->setDeprecated(true, $deprecated[0]->nodeValue);
+            $definition->setDeprecated(true, $deprecated[0]->nodeValue ?: null);
         }
 
         $definition->setArguments($this->getArgumentsAsPhp($service, 'argument'));

Tests/Fixtures/xml/services_deprecated.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<container xmlns="http://symfony.com/schema/dic/services" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">
+  <services>
+    <service id="foo" class="Foo">
+      <deprecated />
+    </service>
+    <service id="bar" class="Bar">
+      <deprecated>The "%service_id%" service is deprecated.</deprecated>
+    </service>
+  </services>
+</container>

Tests/Loader/XmlFileLoaderTest.php

@@ -301,6 +301,21 @@ public function testParseTagWithEmptyNameThrowsException()
         $loader->load('tag_with_empty_name.xml');
     }
 
+    public function testDeprecated()
+    {
+        $container = new ContainerBuilder();
+        $loader = new XmlFileLoader($container, new FileLocator(self::$fixturesPath.'/xml'));
+        $loader->load('services_deprecated.xml');
+
+        $this->assertTrue($container->getDefinition('foo')->isDeprecated());
+        $message = 'The "foo" service is deprecated. You should stop using it, as it will soon be removed.';
+        $this->assertSame($message, $container->getDefinition('foo')->getDeprecationMessage('foo'));
+
+        $this->assertTrue($container->getDefinition('bar')->isDeprecated());
+        $message = 'The "bar" service is deprecated.';
+        $this->assertSame($message, $container->getDefinition('bar')->getDeprecationMessage('bar'));
+    }
+
     public function testConvertDomElementToArray()
     {
         $doc = new \DOMDocument('1.0');