Merge branch '3.4' into 4.0

* 3.4:
  [HttpKernel] Better handling of legacy cache
  modify definitions only if the do exist
  [DI] Prevent a ReflectionException during cache:clear when the parent class doesn't exist
  [FrameworkBundle] Make MicroKernelTraitTest green
  don't override existing verbosity env var
  [HttpKernel] Read $_ENV when checking SHELL_VERBOSITY
  Remove unreachable code
  Automatically enable the CSRF protection if CSRF manager exists
  bumped Symfony version to 3.4.0
  adding checks for the expression language
  updated VERSION for 3.4.0-RC2
  updated CHANGELOG for 3.4.0-RC2

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php

@@ -21,6 +21,7 @@ use Symfony\Component\Config\Definition\ConfigurationInterface;
 use Symfony\Component\Form\Form;
 use Symfony\Component\Lock\Lock;
 use Symfony\Component\Lock\Store\SemaphoreStore;
+use Symfony\Component\Security\Csrf\CsrfTokenManagerInterface;
 use Symfony\Component\Serializer\Serializer;
 use Symfony\Component\Translation\Translator;
 use Symfony\Component\Validator\Validation;
@@ -109,7 +110,7 @@ class Configuration implements ConfigurationInterface
         $rootNode
             ->children()
                 ->arrayNode('csrf_protection')
-                    ->canBeEnabled()
+                    ->{!class_exists(FullStack::class) && class_exists(CsrfTokenManagerInterface::class) ? 'canBeDisabled' : 'canBeEnabled'}()
                 ->end()
             ->end()
         ;

src/Symfony/Bundle/FrameworkBundle/Tests/Kernel/MicroKernelTraitTest.php

@@ -18,7 +18,7 @@ class MicroKernelTraitTest extends TestCase
 {
     public function test()
     {
-        $kernel = new ConcreteMicroKernel('test', true);
+        $kernel = new ConcreteMicroKernel('test', false);
         $kernel->boot();
 
         $request = Request::create('/');
@@ -31,7 +31,7 @@ class MicroKernelTraitTest extends TestCase
 
     public function testAsEventSubscriber()
     {
-        $kernel = new ConcreteMicroKernel('test', true);
+        $kernel = new ConcreteMicroKernel('test', false);
         $kernel->boot();
 
         $request = Request::create('/danger');

src/Symfony/Component/DependencyInjection/Compiler/RegisterServiceSubscribersPass.php

@@ -74,9 +74,6 @@ class RegisterServiceSubscribersPass extends AbstractRecursivePass
             if ($optionalBehavior = '?' === $type[0]) {
                 $type = substr($type, 1);
                 $optionalBehavior = ContainerInterface::IGNORE_ON_INVALID_REFERENCE;
-            } elseif ($optionalBehavior = '!' === $type[0]) {
-                $type = substr($type, 1);
-                $optionalBehavior = ContainerInterface::IGNORE_ON_UNINITIALIZED_REFERENCE;
             }
             if (is_int($key)) {
                 $key = $type;

src/Symfony/Component/DependencyInjection/Dumper/PhpDumper.php

@@ -375,7 +375,7 @@ EOTXT
         if (isset($lineage[$class])) {
             return;
         }
-        if (!$r = $this->container->getReflectionClass($class)) {
+        if (!$r = $this->container->getReflectionClass($class, false)) {
             return;
         }
         if ($this->container instanceof $class) {

src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php

@@ -488,6 +488,10 @@ class XmlFileLoader extends FileLoader
                     $arguments[$key] = new Reference($arg->getAttribute('id'), $invalidBehavior);
                     break;
                 case 'expression':
+                    if (!class_exists(Expression::class)) {
+                        throw new \LogicException(sprintf('The type="expression" attribute cannot be used without the ExpressionLanguage component. Try running "composer require symfony/expression-language".'));
+                    }
+
                     $arguments[$key] = new Expression($arg->nodeValue);
                     break;
                 case 'collection':

src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php

@@ -727,6 +727,10 @@ class YamlFileLoader extends FileLoader
                 $value[$k] = $this->resolveServices($v, $file, $isParameter);
             }
         } elseif (is_string($value) && 0 === strpos($value, '@=')) {
+            if (!class_exists(Expression::class)) {
+                throw new \LogicException(sprintf('The "@=" expression syntax cannot be used without the ExpressionLanguage component. Try running "composer require symfony/expression-language".'));
+            }
+
             return new Expression(substr($value, 2));
         } elseif (is_string($value) && 0 === strpos($value, '@')) {
             if (0 === strpos($value, '@@')) {

src/Symfony/Component/DependencyInjection/Tests/Fixtures/ParentNotExists.php

@@ -0,0 +1,7 @@
+<?php
+
+namespace Symfony\Component\DependencyInjection\Tests\Fixtures;
+
+class ParentNotExists extends \NotExists
+{
+}

src/Symfony/Component/DependencyInjection/Tests/Fixtures/containers/container_inline_requires.php

@@ -7,11 +7,13 @@ use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\Dumper\PhpDumper;
 use Symfony\Component\DependencyInjection\Reference;
 use Symfony\Component\DependencyInjection\Tests\Fixtures\includes\HotPath;
+use Symfony\Component\DependencyInjection\Tests\Fixtures\ParentNotExists;
 
 $container = new ContainerBuilder();
 
 $container->register(HotPath\C1::class)->addTag('container.hot_path')->setPublic(true);
 $container->register(HotPath\C2::class)->addArgument(new Reference(HotPath\C3::class))->setPublic(true);
 $container->register(HotPath\C3::class);
+$container->register(ParentNotExists::class)->setPublic(true);
 
 return $container;

src/Symfony/Component/DependencyInjection/Tests/Fixtures/php/container_inline_requires.php

@@ -30,6 +30,7 @@ class ProjectServiceContainer extends Container
 
         $this->services = $this->privates = array();
         $this->methodMap = array(
+            'Symfony\\Component\\DependencyInjection\\Tests\\Fixtures\\ParentNotExists' => 'getParentNotExistsService',
             'Symfony\\Component\\DependencyInjection\\Tests\\Fixtures\\includes\\HotPath\\C1' => 'getC1Service',
             'Symfony\\Component\\DependencyInjection\\Tests\\Fixtures\\includes\\HotPath\\C2' => 'getC2Service',
         );
@@ -67,6 +68,16 @@ class ProjectServiceContainer extends Container
         );
     }
 
+    /**
+     * Gets the public 'Symfony\Component\DependencyInjection\Tests\Fixtures\ParentNotExists' shared service.
+     *
+     * @return \Symfony\Component\DependencyInjection\Tests\Fixtures\ParentNotExists
+     */
+    protected function getParentNotExistsService()
+    {
+        return $this->services['Symfony\Component\DependencyInjection\Tests\Fixtures\ParentNotExists'] = new \Symfony\Component\DependencyInjection\Tests\Fixtures\ParentNotExists();
+    }
+
     /**
      * Gets the public 'Symfony\Component\DependencyInjection\Tests\Fixtures\includes\HotPath\C1' shared service.
      *

src/Symfony/Component/HttpKernel/Kernel.php

@@ -112,7 +112,7 @@ abstract class Kernel implements KernelInterface, RebootableInterface, Terminabl
 
             return;
         }
-        if ($this->debug && !isset($_SERVER['SHELL_VERBOSITY'])) {
+        if ($this->debug && !isset($_ENV['SHELL_VERBOSITY']) && !isset($_SERVER['SHELL_VERBOSITY'])) {
             putenv('SHELL_VERBOSITY=3');
             $_ENV['SHELL_VERBOSITY'] = 3;
             $_SERVER['SHELL_VERBOSITY'] = 3;
@@ -451,8 +451,11 @@ abstract class Kernel implements KernelInterface, RebootableInterface, Terminabl
         $class = $this->getContainerClass();
         $cacheDir = $this->warmupDir ?: $this->getCacheDir();
         $cache = new ConfigCache($cacheDir.'/'.$class.'.php', $this->debug);
-        $fresh = true;
-        if (!$cache->isFresh()) {
+        if ($fresh = $cache->isFresh()) {
+            $this->container = require $cache->getPath();
+            $fresh = \is_object($this->container);
+        }
+        if (!$fresh) {
             if ($this->debug) {
                 $collectedLogs = array();
                 $previousHandler = set_error_handler(function ($type, $message, $file, $line) use (&$collectedLogs, &$previousHandler) {
@@ -502,11 +505,9 @@ abstract class Kernel implements KernelInterface, RebootableInterface, Terminabl
             $oldContainer = file_exists($cache->getPath()) && is_object($oldContainer = @include $cache->getPath()) ? new \ReflectionClass($oldContainer) : false;
 
             $this->dumpContainer($cache, $container, $class, $this->getContainerBaseClass());
-
-            $fresh = false;
+            $this->container = require $cache->getPath();
         }
 
-        $this->container = require $cache->getPath();
         $this->container->set('kernel', $this);
 
         if ($fresh) {

src/Symfony/Component/HttpKernel/Log/Logger.php

@@ -42,8 +42,8 @@ class Logger extends AbstractLogger
         if (null === $minLevel) {
             $minLevel = LogLevel::WARNING;
 
-            if (isset($_SERVER['SHELL_VERBOSITY'])) {
-                switch ((int) $_SERVER['SHELL_VERBOSITY']) {
+            if (isset($_ENV['SHELL_VERBOSITY']) || isset($_SERVER['SHELL_VERBOSITY'])) {
+                switch ((int) (isset($_ENV['SHELL_VERBOSITY']) ? $_ENV['SHELL_VERBOSITY'] : $_SERVER['SHELL_VERBOSITY'])) {
                     case -1: $minLevel = LogLevel::ERROR; break;
                     case 1: $minLevel = LogLevel::NOTICE; break;
                     case 2: $minLevel = LogLevel::INFO; break;

src/Symfony/Component/Translation/DependencyInjection/TranslatorPass.php

@@ -64,8 +64,15 @@ class TranslatorPass implements CompilerPassInterface
             ->replaceArgument(3, $loaders)
         ;
 
-        if ($container->hasParameter('twig.default_path')) {
+        if (!$container->hasParameter('twig.default_path')) {
+            return;
+        }
+
+        if ($container->hasDefinition($this->debugCommandServiceId)) {
             $container->getDefinition($this->debugCommandServiceId)->replaceArgument(4, $container->getParameter('twig.default_path'));
+        }
+
+        if ($container->hasDefinition($this->updateCommandServiceId)) {
             $container->getDefinition($this->updateCommandServiceId)->replaceArgument(5, $container->getParameter('twig.default_path'));
         }
     }