diff --git a/.travis.yml b/.travis.yml
index b5e7eb9ecd..373a61f732 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -190,7 +190,7 @@ install:
           export SYMFONY_DEPRECATIONS_HELPER=weak &&
           cp composer.json composer.json.orig &&
           echo -e '{\n"require":{'"$(grep phpunit-bridge composer.json)"'"php":"*"},"minimum-stability":"dev"}' > composer.json &&
-          php .github/build-packages.php HEAD^ $COMPONENTS &&
+          php .github/build-packages.php HEAD^ $(find src/Symfony -mindepth 3 -type f -name composer.json -printf '%h\n') &&
           mv composer.json composer.json.phpunit &&
           mv composer.json.orig composer.json
       fi
diff --git a/src/Symfony/Bridge/Twig/AppVariable.php b/src/Symfony/Bridge/Twig/AppVariable.php
index 7c1a8f18f2..44fc3d41d5 100644
--- a/src/Symfony/Bridge/Twig/AppVariable.php
+++ b/src/Symfony/Bridge/Twig/AppVariable.php
@@ -112,10 +112,9 @@ class AppVariable
         if (null === $this->requestStack) {
             throw new \RuntimeException('The "app.session" variable is not available.');
         }
+        $request = $this->getRequest();
 
-        if ($request = $this->getRequest()) {
-            return $request->getSession();
-        }
+        return $request && $request->hasSession() ? $request->getSession() : null;
     }
 
     /**
@@ -157,8 +156,7 @@ class AppVariable
     public function getFlashes($types = null)
     {
         try {
-            $session = $this->getSession();
-            if (null === $session) {
+            if (null === $session = $this->getSession()) {
                 return [];
             }
         } catch (\RuntimeException $e) {
diff --git a/src/Symfony/Bridge/Twig/Tests/AppVariableTest.php b/src/Symfony/Bridge/Twig/Tests/AppVariableTest.php
index 53b84b2d1b..b6699e5cdc 100644
--- a/src/Symfony/Bridge/Twig/Tests/AppVariableTest.php
+++ b/src/Symfony/Bridge/Twig/Tests/AppVariableTest.php
@@ -51,6 +51,7 @@ class AppVariableTest extends TestCase
     public function testGetSession()
     {
         $request = $this->getMockBuilder('Symfony\Component\HttpFoundation\Request')->getMock();
+        $request->method('hasSession')->willReturn(true);
         $request->method('getSession')->willReturn($session = new Session());
 
         $this->setRequestStack($request);
@@ -267,6 +268,7 @@ class AppVariableTest extends TestCase
         $session->method('getFlashBag')->willReturn($flashBag);
 
         $request = $this->getMockBuilder('Symfony\Component\HttpFoundation\Request')->getMock();
+        $request->method('hasSession')->willReturn(true);
         $request->method('getSession')->willReturn($session);
         $this->setRequestStack($request);
 
diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php
index 6765f66e6c..b1da089cfd 100644
--- a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php
+++ b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php
@@ -1016,7 +1016,7 @@ class FrameworkExtension extends Extension
         }
         $defaultDir = $container->getParameterBag()->resolveValue($config['default_path']);
         foreach ($container->getParameter('kernel.bundles_metadata') as $name => $bundle) {
-            if (is_dir($dir = $bundle['path'].'/Resources/translations')) {
+            if ($container->fileExists($dir = $bundle['path'].'/Resources/translations')) {
                 $dirs[] = $dir;
             } else {
                 $nonExistingDirs[] = $dir;
@@ -1024,7 +1024,7 @@ class FrameworkExtension extends Extension
         }
 
         foreach ($config['paths'] as $dir) {
-            if (is_dir($dir)) {
+            if ($container->fileExists($dir)) {
                 $dirs[] = $transPaths[] = $dir;
             } else {
                 throw new \UnexpectedValueException(sprintf('%s defined in translator.paths does not exist or is not a directory', $dir));
@@ -1039,7 +1039,7 @@ class FrameworkExtension extends Extension
             $container->getDefinition('console.command.translation_update')->replaceArgument(6, $transPaths);
         }
 
-        if (is_dir($defaultDir)) {
+        if ($container->fileExists($defaultDir)) {
             $dirs[] = $defaultDir;
         } else {
             $nonExistingDirs[] = $defaultDir;
diff --git a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTest.php b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTest.php
index e75dbf359f..220bff1764 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTest.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTest.php
@@ -26,8 +26,6 @@ use Symfony\Component\Cache\Adapter\FilesystemAdapter;
 use Symfony\Component\Cache\Adapter\ProxyAdapter;
 use Symfony\Component\Cache\Adapter\RedisAdapter;
 use Symfony\Component\Cache\DependencyInjection\CachePoolPass;
-use Symfony\Component\Config\Resource\DirectoryResource;
-use Symfony\Component\Config\Resource\FileExistenceResource;
 use Symfony\Component\DependencyInjection\ChildDefinition;
 use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
 use Symfony\Component\DependencyInjection\Compiler\ResolveInstanceofConditionalsPass;
@@ -745,17 +743,6 @@ abstract class FrameworkExtensionTest extends TestCase
         );
 
         $this->assertNotEmpty($nonExistingDirectories, 'FrameworkBundle should pass non existing directories to Translator');
-
-        $resources = $container->getResources();
-        foreach ($resources as $resource) {
-            if ($resource instanceof DirectoryResource) {
-                $this->assertNotContains('translations', $resource->getResource());
-            }
-
-            if ($resource instanceof FileExistenceResource) {
-                $this->assertNotContains('translations', $resource->getResource());
-            }
-        }
     }
 
     public function testTranslatorMultipleFallbacks()
diff --git a/src/Symfony/Bundle/WebProfilerBundle/Controller/ProfilerController.php b/src/Symfony/Bundle/WebProfilerBundle/Controller/ProfilerController.php
index be067b7af2..fde54c9b65 100644
--- a/src/Symfony/Bundle/WebProfilerBundle/Controller/ProfilerController.php
+++ b/src/Symfony/Bundle/WebProfilerBundle/Controller/ProfilerController.php
@@ -117,7 +117,7 @@ class ProfilerController
             throw new NotFoundHttpException('The profiler must be enabled.');
         }
 
-        if ($request->hasSession() && ($session = $request->getSession()) && $session->isStarted() && $session->getFlashBag() instanceof AutoExpireFlashBag) {
+        if ($request->hasSession() && ($session = $request->getSession())->isStarted() && $session->getFlashBag() instanceof AutoExpireFlashBag) {
             // keep current flashes for one more request if using AutoExpireFlashBag
             $session->getFlashBag()->setAll($session->getFlashBag()->peekAll());
         }
diff --git a/src/Symfony/Bundle/WebProfilerBundle/EventListener/WebDebugToolbarListener.php b/src/Symfony/Bundle/WebProfilerBundle/EventListener/WebDebugToolbarListener.php
index 075891c81d..e960d9b38b 100644
--- a/src/Symfony/Bundle/WebProfilerBundle/EventListener/WebDebugToolbarListener.php
+++ b/src/Symfony/Bundle/WebProfilerBundle/EventListener/WebDebugToolbarListener.php
@@ -88,8 +88,7 @@ class WebDebugToolbarListener implements EventSubscriberInterface
         }
 
         if ($response->headers->has('X-Debug-Token') && $response->isRedirect() && $this->interceptRedirects && 'html' === $request->getRequestFormat()) {
-            $session = $request->getSession();
-            if (null !== $session && $session->isStarted() && $session->getFlashBag() instanceof AutoExpireFlashBag) {
+            if ($request->hasSession() && ($session = $request->getSession())->isStarted() && $session->getFlashBag() instanceof AutoExpireFlashBag) {
                 // keep current flashes for one more request if using AutoExpireFlashBag
                 $session->getFlashBag()->setAll($session->getFlashBag()->peekAll());
             }
diff --git a/src/Symfony/Component/Cache/Adapter/AbstractAdapter.php b/src/Symfony/Component/Cache/Adapter/AbstractAdapter.php
index 7d54922f39..2f91434575 100644
--- a/src/Symfony/Component/Cache/Adapter/AbstractAdapter.php
+++ b/src/Symfony/Component/Cache/Adapter/AbstractAdapter.php
@@ -44,7 +44,7 @@ abstract class AbstractAdapter implements AdapterInterface, CacheInterface, Logg
             throw new InvalidArgumentException(sprintf('Namespace must be %d chars max, %d given ("%s")', $this->maxIdLength - 24, \strlen($namespace), $namespace));
         }
         $this->createCacheItem = \Closure::bind(
-            function ($key, $value, $isHit) use ($defaultLifetime) {
+            static function ($key, $value, $isHit) use ($defaultLifetime) {
                 $item = new CacheItem();
                 $item->key = $key;
                 $item->value = $v = $value;
@@ -67,7 +67,7 @@ abstract class AbstractAdapter implements AdapterInterface, CacheInterface, Logg
         );
         $getId = \Closure::fromCallable([$this, 'getId']);
         $this->mergeByLifetime = \Closure::bind(
-            function ($deferred, $namespace, &$expiredIds) use ($getId) {
+            static function ($deferred, $namespace, &$expiredIds) use ($getId) {
                 $byLifetime = [];
                 $now = microtime(true);
                 $expiredIds = [];
diff --git a/src/Symfony/Component/Cache/Adapter/ArrayAdapter.php b/src/Symfony/Component/Cache/Adapter/ArrayAdapter.php
index 3a237bb30a..b7d7151121 100644
--- a/src/Symfony/Component/Cache/Adapter/ArrayAdapter.php
+++ b/src/Symfony/Component/Cache/Adapter/ArrayAdapter.php
@@ -37,7 +37,7 @@ class ArrayAdapter implements AdapterInterface, CacheInterface, LoggerAwareInter
     {
         $this->storeSerialized = $storeSerialized;
         $this->createCacheItem = \Closure::bind(
-            function ($key, $value, $isHit) use ($defaultLifetime) {
+            static function ($key, $value, $isHit) use ($defaultLifetime) {
                 $item = new CacheItem();
                 $item->key = $key;
                 $item->value = $value;
diff --git a/src/Symfony/Component/Cache/Adapter/ChainAdapter.php b/src/Symfony/Component/Cache/Adapter/ChainAdapter.php
index 2ab47f47ea..d023aeedbd 100644
--- a/src/Symfony/Component/Cache/Adapter/ChainAdapter.php
+++ b/src/Symfony/Component/Cache/Adapter/ChainAdapter.php
@@ -61,7 +61,7 @@ class ChainAdapter implements AdapterInterface, CacheInterface, PruneableInterfa
         $this->adapterCount = \count($this->adapters);
 
         $this->syncItem = \Closure::bind(
-            function ($sourceItem, $item) use ($defaultLifetime) {
+            static function ($sourceItem, $item) use ($defaultLifetime) {
                 $item->value = $sourceItem->value;
                 $item->expiry = $sourceItem->expiry;
                 $item->isHit = $sourceItem->isHit;
diff --git a/src/Symfony/Component/Cache/Adapter/PhpArrayAdapter.php b/src/Symfony/Component/Cache/Adapter/PhpArrayAdapter.php
index ca4294e646..7b9a4a426a 100644
--- a/src/Symfony/Component/Cache/Adapter/PhpArrayAdapter.php
+++ b/src/Symfony/Component/Cache/Adapter/PhpArrayAdapter.php
@@ -48,7 +48,7 @@ class PhpArrayAdapter implements AdapterInterface, CacheInterface, PruneableInte
         $this->file = $file;
         $this->pool = $fallbackPool;
         $this->createCacheItem = \Closure::bind(
-            function ($key, $value, $isHit) {
+            static function ($key, $value, $isHit) {
                 $item = new CacheItem();
                 $item->key = $key;
                 $item->value = $value;
diff --git a/src/Symfony/Component/Cache/Adapter/ProxyAdapter.php b/src/Symfony/Component/Cache/Adapter/ProxyAdapter.php
index 75d0d60a45..e0404d054a 100644
--- a/src/Symfony/Component/Cache/Adapter/ProxyAdapter.php
+++ b/src/Symfony/Component/Cache/Adapter/ProxyAdapter.php
@@ -41,7 +41,7 @@ class ProxyAdapter implements AdapterInterface, CacheInterface, PruneableInterfa
         $this->namespace = '' === $namespace ? '' : CacheItem::validateKey($namespace);
         $this->namespaceLen = \strlen($namespace);
         $this->createCacheItem = \Closure::bind(
-            function ($key, $innerItem) use ($defaultLifetime, $poolHash) {
+            static function ($key, $innerItem) use ($defaultLifetime, $poolHash) {
                 $item = new CacheItem();
                 $item->key = $key;
 
@@ -77,7 +77,7 @@ class ProxyAdapter implements AdapterInterface, CacheInterface, PruneableInterfa
             /**
              * @param array $item A CacheItem cast to (array); accessing protected properties requires adding the "\0*\0" PHP prefix
              */
-            function (CacheItemInterface $innerItem, array $item) {
+            static function (CacheItemInterface $innerItem, array $item) {
                 // Tags are stored separately, no need to account for them when considering this item's newly set metadata
                 if (isset(($metadata = $item["\0*\0newMetadata"])[CacheItem::METADATA_TAGS])) {
                     unset($metadata[CacheItem::METADATA_TAGS]);
diff --git a/src/Symfony/Component/Cache/Adapter/TagAwareAdapter.php b/src/Symfony/Component/Cache/Adapter/TagAwareAdapter.php
index 3a04dc01f1..f17bd3b73c 100644
--- a/src/Symfony/Component/Cache/Adapter/TagAwareAdapter.php
+++ b/src/Symfony/Component/Cache/Adapter/TagAwareAdapter.php
@@ -45,7 +45,7 @@ class TagAwareAdapter implements TagAwareAdapterInterface, TagAwareCacheInterfac
         $this->tags = $tagsPool ?: $itemsPool;
         $this->knownTagVersionsTtl = $knownTagVersionsTtl;
         $this->createCacheItem = \Closure::bind(
-            function ($key, $value, CacheItem $protoItem) {
+            static function ($key, $value, CacheItem $protoItem) {
                 $item = new CacheItem();
                 $item->key = $key;
                 $item->value = $value;
@@ -59,7 +59,7 @@ class TagAwareAdapter implements TagAwareAdapterInterface, TagAwareCacheInterfac
             CacheItem::class
         );
         $this->setCacheItemTags = \Closure::bind(
-            function (CacheItem $item, $key, array &$itemTags) {
+            static function (CacheItem $item, $key, array &$itemTags) {
                 $item->isTaggable = true;
                 if (!$item->isHit) {
                     return $item;
@@ -80,7 +80,7 @@ class TagAwareAdapter implements TagAwareAdapterInterface, TagAwareCacheInterfac
             CacheItem::class
         );
         $this->getTagsByKey = \Closure::bind(
-            function ($deferred) {
+            static function ($deferred) {
                 $tagsByKey = [];
                 foreach ($deferred as $key => $item) {
                     $tagsByKey[$key] = $item->newMetadata[CacheItem::METADATA_TAGS] ?? [];
@@ -92,7 +92,7 @@ class TagAwareAdapter implements TagAwareAdapterInterface, TagAwareCacheInterfac
             CacheItem::class
         );
         $this->invalidateTags = \Closure::bind(
-            function (AdapterInterface $tagsAdapter, array $tags) {
+            static function (AdapterInterface $tagsAdapter, array $tags) {
                 foreach ($tags as $v) {
                     $v->defaultLifetime = 0;
                     $v->expiry = null;
diff --git a/src/Symfony/Component/Cache/Psr16Cache.php b/src/Symfony/Component/Cache/Psr16Cache.php
index 589ffa0d8b..d67615eb77 100644
--- a/src/Symfony/Component/Cache/Psr16Cache.php
+++ b/src/Symfony/Component/Cache/Psr16Cache.php
@@ -42,7 +42,7 @@ class Psr16Cache implements CacheInterface, PruneableInterface, ResettableInterf
         }
         $cacheItemPrototype = &$this->cacheItemPrototype;
         $createCacheItem = \Closure::bind(
-            function ($key, $value, $allowInt = false) use (&$cacheItemPrototype) {
+            static function ($key, $value, $allowInt = false) use (&$cacheItemPrototype) {
                 $item = clone $cacheItemPrototype;
                 $item->key = $allowInt && \is_int($key) ? (string) $key : CacheItem::validateKey($key);
                 $item->value = $value;
diff --git a/src/Symfony/Component/Cache/Traits/ContractsTrait.php b/src/Symfony/Component/Cache/Traits/ContractsTrait.php
index d9514d3965..7f99f65fdf 100644
--- a/src/Symfony/Component/Cache/Traits/ContractsTrait.php
+++ b/src/Symfony/Component/Cache/Traits/ContractsTrait.php
@@ -58,7 +58,7 @@ trait ContractsTrait
         static $setMetadata;
 
         $setMetadata = $setMetadata ?? \Closure::bind(
-            function (CacheItem $item, float $startTime, ?array &$metadata) {
+            static function (CacheItem $item, float $startTime, ?array &$metadata) {
                 if ($item->expiry > $endTime = microtime(true)) {
                     $item->newMetadata[CacheItem::METADATA_EXPIRY] = $metadata[CacheItem::METADATA_EXPIRY] = $item->expiry;
                     $item->newMetadata[CacheItem::METADATA_CTIME] = $metadata[CacheItem::METADATA_CTIME] = 1000 * (int) ($endTime - $startTime);
diff --git a/src/Symfony/Component/Config/Resource/ReflectionClassResource.php b/src/Symfony/Component/Config/Resource/ReflectionClassResource.php
index 78a0abfceb..87b99af749 100644
--- a/src/Symfony/Component/Config/Resource/ReflectionClassResource.php
+++ b/src/Symfony/Component/Config/Resource/ReflectionClassResource.php
@@ -138,7 +138,7 @@ class ReflectionClassResource implements SelfCheckingResourceInterface
 
             foreach ($class->getProperties(\ReflectionProperty::IS_PUBLIC | \ReflectionProperty::IS_PROTECTED) as $p) {
                 yield $p->getDocComment().$p;
-                yield print_r(isset($defaults[$p->name]) ? $defaults[$p->name] : null, true);
+                yield print_r(isset($defaults[$p->name]) && !\is_object($defaults[$p->name]) ? $defaults[$p->name] : null, true);
             }
         }
 
diff --git a/src/Symfony/Component/Config/Tests/Resource/ReflectionClassResourceTest.php b/src/Symfony/Component/Config/Tests/Resource/ReflectionClassResourceTest.php
index 1cf8398a29..43a077f56c 100644
--- a/src/Symfony/Component/Config/Tests/Resource/ReflectionClassResourceTest.php
+++ b/src/Symfony/Component/Config/Tests/Resource/ReflectionClassResourceTest.php
@@ -185,6 +185,15 @@ EOPHP;
         $res = new ReflectionClassResource(new \ReflectionClass(TestServiceSubscriber::class));
         $this->assertTrue($res->isFresh(0));
     }
+
+    public function testIgnoresObjectsInSignature()
+    {
+        $res = new ReflectionClassResource(new \ReflectionClass(TestServiceWithStaticProperty::class));
+        $this->assertTrue($res->isFresh(0));
+
+        TestServiceWithStaticProperty::$initializedObject = new TestServiceWithStaticProperty();
+        $this->assertTrue($res->isFresh(0));
+    }
 }
 
 interface DummyInterface
@@ -224,3 +233,8 @@ class TestServiceSubscriber implements ServiceSubscriberInterface
         return self::$subscribedServices;
     }
 }
+
+class TestServiceWithStaticProperty
+{
+    public static $initializedObject;
+}
diff --git a/src/Symfony/Component/Console/Input/ArrayInput.php b/src/Symfony/Component/Console/Input/ArrayInput.php
index b409960440..ca51a48502 100644
--- a/src/Symfony/Component/Console/Input/ArrayInput.php
+++ b/src/Symfony/Component/Console/Input/ArrayInput.php
@@ -132,7 +132,7 @@ class ArrayInput extends Input
             }
             if (0 === strpos($key, '--')) {
                 $this->addLongOption(substr($key, 2), $value);
-            } elseif ('-' === $key[0]) {
+            } elseif (0 === strpos($key, '-')) {
                 $this->addShortOption(substr($key, 1), $value);
             } else {
                 $this->addArgument($key, $value);
diff --git a/src/Symfony/Component/DependencyInjection/Compiler/PassConfig.php b/src/Symfony/Component/DependencyInjection/Compiler/PassConfig.php
index f11b148ea4..edb3032090 100644
--- a/src/Symfony/Component/DependencyInjection/Compiler/PassConfig.php
+++ b/src/Symfony/Component/DependencyInjection/Compiler/PassConfig.php
@@ -51,15 +51,15 @@ class PassConfig
         $this->optimizationPasses = [[
             new ValidateEnvPlaceholdersPass(),
             new ResolveChildDefinitionsPass(),
-            new ServiceLocatorTagPass(),
             new RegisterServiceSubscribersPass(),
             new DecoratorServicePass(),
             new ResolveParameterPlaceHoldersPass(false),
             new ResolveFactoryClassPass(),
-            new CheckDefinitionValidityPass(),
             new ResolveNamedArgumentsPass(),
             new AutowireRequiredMethodsPass(),
             new ResolveBindingsPass(),
+            new ServiceLocatorTagPass(),
+            new CheckDefinitionValidityPass(),
             new AutowirePass(false),
             new ResolveTaggedIteratorArgumentPass(),
             new ResolveServiceSubscribersPass(),
diff --git a/src/Symfony/Component/HttpFoundation/File/UploadedFile.php b/src/Symfony/Component/HttpFoundation/File/UploadedFile.php
index baf9c3a449..b7cd6a4e00 100644
--- a/src/Symfony/Component/HttpFoundation/File/UploadedFile.php
+++ b/src/Symfony/Component/HttpFoundation/File/UploadedFile.php
@@ -219,13 +219,26 @@ class UploadedFile extends File
      */
     public static function getMaxFilesize()
     {
-        $iniMax = strtolower(ini_get('upload_max_filesize'));
+        $sizePostMax = self::parseFilesize(ini_get('post_max_size'));
+        $sizeUploadMax = self::parseFilesize(ini_get('upload_max_filesize'));
 
-        if ('' === $iniMax) {
-            return PHP_INT_MAX;
+        return min([$sizePostMax, $sizeUploadMax]);
+    }
+
+    /**
+     * Returns the given size from an ini value in bytes.
+     *
+     * @return int The given size in bytes
+     */
+    private static function parseFilesize($size)
+    {
+        if ('' === $size) {
+            return 0;
         }
 
-        $max = ltrim($iniMax, '+');
+        $size = strtolower($size);
+
+        $max = ltrim($size, '+');
         if (0 === strpos($max, '0x')) {
             $max = \intval($max, 16);
         } elseif (0 === strpos($max, '0')) {
@@ -234,7 +247,7 @@ class UploadedFile extends File
             $max = (int) $max;
         }
 
-        switch (substr($iniMax, -1)) {
+        switch (substr($size, -1)) {
             case 't': $max *= 1024;
             // no break
             case 'g': $max *= 1024;
diff --git a/src/Symfony/Component/HttpKernel/EventListener/AbstractTestSessionListener.php b/src/Symfony/Component/HttpKernel/EventListener/AbstractTestSessionListener.php
index b5d0f148cc..fa1e8a5fda 100644
--- a/src/Symfony/Component/HttpKernel/EventListener/AbstractTestSessionListener.php
+++ b/src/Symfony/Component/HttpKernel/EventListener/AbstractTestSessionListener.php
@@ -46,8 +46,7 @@ abstract class AbstractTestSessionListener implements EventSubscriberInterface
         }
 
         // bootstrap the session
-        $session = $this->getSession();
-        if (!$session) {
+        if (!$session = $this->getSession()) {
             return;
         }
 
diff --git a/src/Symfony/Component/HttpKernel/Fragment/InlineFragmentRenderer.php b/src/Symfony/Component/HttpKernel/Fragment/InlineFragmentRenderer.php
index 6493fc86f6..3bbdbd3ce8 100644
--- a/src/Symfony/Component/HttpKernel/Fragment/InlineFragmentRenderer.php
+++ b/src/Symfony/Component/HttpKernel/Fragment/InlineFragmentRenderer.php
@@ -121,7 +121,7 @@ class InlineFragmentRenderer extends RoutableFragmentRenderer
         static $setSession;
 
         if (null === $setSession) {
-            $setSession = \Closure::bind(function ($subRequest, $request) { $subRequest->session = $request->session; }, null, Request::class);
+            $setSession = \Closure::bind(static function ($subRequest, $request) { $subRequest->session = $request->session; }, null, Request::class);
         }
         $setSession($subRequest, $request);
 
diff --git a/src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php b/src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php
index 982e8cdb9a..eb128b0521 100644
--- a/src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php
+++ b/src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php
@@ -98,8 +98,8 @@ class HttpCache implements HttpKernelInterface, TerminableInterface
             'trace_header' => 'X-Symfony-Cache',
         ], $options);
 
-        if (!isset($options['trace_level']) && $this->options['debug']) {
-            $this->options['trace_level'] = 'full';
+        if (!isset($options['trace_level'])) {
+            $this->options['trace_level'] = $this->options['debug'] ? 'full' : 'none';
         }
     }
 
diff --git a/src/Symfony/Component/Lock/BlockingStoreInterface.php b/src/Symfony/Component/Lock/BlockingStoreInterface.php
index 162c9b3d41..15efaa2bdf 100644
--- a/src/Symfony/Component/Lock/BlockingStoreInterface.php
+++ b/src/Symfony/Component/Lock/BlockingStoreInterface.php
@@ -16,7 +16,7 @@ use Symfony\Component\Lock\Exception\LockConflictedException;
 /**
  * @author Hamza Amrouche <hamza.simperfit@gmail.com>
  */
-interface BlockingStoreInterface
+interface BlockingStoreInterface extends PersistingStoreInterface
 {
     /**
      * Waits until a key becomes free, then stores the resource.
diff --git a/src/Symfony/Component/Lock/Store/RetryTillSaveStore.php b/src/Symfony/Component/Lock/Store/RetryTillSaveStore.php
index 81185f59eb..9a412810c2 100644
--- a/src/Symfony/Component/Lock/Store/RetryTillSaveStore.php
+++ b/src/Symfony/Component/Lock/Store/RetryTillSaveStore.php
@@ -26,7 +26,7 @@ use Symfony\Component\Lock\StoreInterface;
  *
  * @author Jérémy Derussé <jeremy@derusse.com>
  */
-class RetryTillSaveStore implements PersistingStoreInterface, BlockingStoreInterface, StoreInterface, LoggerAwareInterface
+class RetryTillSaveStore implements BlockingStoreInterface, StoreInterface, LoggerAwareInterface
 {
     use LoggerAwareTrait;
 
diff --git a/src/Symfony/Component/Lock/Tests/LockTest.php b/src/Symfony/Component/Lock/Tests/LockTest.php
index 87331a64cf..1239ddba0f 100644
--- a/src/Symfony/Component/Lock/Tests/LockTest.php
+++ b/src/Symfony/Component/Lock/Tests/LockTest.php
@@ -97,7 +97,7 @@ class LockTest extends TestCase
     public function testAcquireBlocking()
     {
         $key = new Key(uniqid(__METHOD__, true));
-        $store = $this->getMockBuilder([PersistingStoreInterface::class, BlockingStoreInterface::class])->getMock();
+        $store = $this->createMock(BlockingStoreInterface::class);
         $lock = new Lock($key, $store);
 
         $store
@@ -213,7 +213,7 @@ class LockTest extends TestCase
     public function testReleaseOnDestruction()
     {
         $key = new Key(uniqid(__METHOD__, true));
-        $store = $this->getMockBuilder([PersistingStoreInterface::class, BlockingStoreInterface::class])->getMock();
+        $store = $this->createMock(BlockingStoreInterface::class);
         $lock = new Lock($key, $store, 10);
 
         $store
@@ -232,7 +232,7 @@ class LockTest extends TestCase
     public function testNoAutoReleaseWhenNotConfigured()
     {
         $key = new Key(uniqid(__METHOD__, true));
-        $store = $this->getMockBuilder([PersistingStoreInterface::class, BlockingStoreInterface::class])->getMock();
+        $store = $this->createMock(BlockingStoreInterface::class);
         $lock = new Lock($key, $store, 10, false);
 
         $store
diff --git a/src/Symfony/Component/Lock/Tests/Store/CombinedStoreTest.php b/src/Symfony/Component/Lock/Tests/Store/CombinedStoreTest.php
index 0f77d103d5..15ceb42bb5 100644
--- a/src/Symfony/Component/Lock/Tests/Store/CombinedStoreTest.php
+++ b/src/Symfony/Component/Lock/Tests/Store/CombinedStoreTest.php
@@ -62,8 +62,8 @@ class CombinedStoreTest extends AbstractStoreTest
     protected function setUp()
     {
         $this->strategy = $this->getMockBuilder(StrategyInterface::class)->getMock();
-        $this->store1 = $this->getMockBuilder([PersistingStoreInterface::class, BlockingStoreInterface::class])->getMock();
-        $this->store2 = $this->getMockBuilder([PersistingStoreInterface::class, BlockingStoreInterface::class])->getMock();
+        $this->store1 = $this->createMock(BlockingStoreInterface::class);
+        $this->store2 = $this->createMock(BlockingStoreInterface::class);
 
         $this->store = new CombinedStore([$this->store1, $this->store2], $this->strategy);
     }
diff --git a/src/Symfony/Component/Routing/Loader/PhpFileLoader.php b/src/Symfony/Component/Routing/Loader/PhpFileLoader.php
index 7af543744e..31fe88ddd8 100644
--- a/src/Symfony/Component/Routing/Loader/PhpFileLoader.php
+++ b/src/Symfony/Component/Routing/Loader/PhpFileLoader.php
@@ -40,7 +40,7 @@ class PhpFileLoader extends FileLoader
 
         // the closure forbids access to the private scope in the included file
         $loader = $this;
-        $load = \Closure::bind(function ($file) use ($loader) {
+        $load = \Closure::bind(static function ($file) use ($loader) {
             return include $file;
         }, null, ProtectedPhpFileLoader::class);
 
diff --git a/src/Symfony/Component/Security/Http/Authentication/AuthenticationUtils.php b/src/Symfony/Component/Security/Http/Authentication/AuthenticationUtils.php
index fbdc0bc5eb..af7e4919c3 100644
--- a/src/Symfony/Component/Security/Http/Authentication/AuthenticationUtils.php
+++ b/src/Symfony/Component/Security/Http/Authentication/AuthenticationUtils.php
@@ -38,12 +38,11 @@ class AuthenticationUtils
     public function getLastAuthenticationError($clearSession = true)
     {
         $request = $this->getRequest();
-        $session = $request->getSession();
         $authenticationException = null;
 
         if ($request->attributes->has(Security::AUTHENTICATION_ERROR)) {
             $authenticationException = $request->attributes->get(Security::AUTHENTICATION_ERROR);
-        } elseif (null !== $session && $session->has(Security::AUTHENTICATION_ERROR)) {
+        } elseif ($request->hasSession() && ($session = $request->getSession())->has(Security::AUTHENTICATION_ERROR)) {
             $authenticationException = $session->get(Security::AUTHENTICATION_ERROR);
 
             if ($clearSession) {
@@ -65,9 +64,7 @@ class AuthenticationUtils
             return $request->attributes->get(Security::LAST_USERNAME, '');
         }
 
-        $session = $request->getSession();
-
-        return null === $session ? '' : $session->get(Security::LAST_USERNAME, '');
+        return $request->hasSession() ? $request->getSession()->get(Security::LAST_USERNAME, '') : '';
     }
 
     /**
diff --git a/src/Symfony/Component/Security/Http/Firewall/ContextListener.php b/src/Symfony/Component/Security/Http/Firewall/ContextListener.php
index 470d2a8dc4..09f170bf45 100644
--- a/src/Symfony/Component/Security/Http/Firewall/ContextListener.php
+++ b/src/Symfony/Component/Security/Http/Firewall/ContextListener.php
@@ -75,7 +75,7 @@ class ContextListener
         }
 
         $request = $event->getRequest();
-        $session = $request->hasPreviousSession() ? $request->getSession() : null;
+        $session = $request->hasPreviousSession() && $request->hasSession() ? $request->getSession() : null;
 
         if (null === $session || null === $token = $session->get($this->sessionKey)) {
             $this->tokenStorage->setToken(null);
@@ -122,14 +122,14 @@ class ContextListener
 
         $this->dispatcher->removeListener(KernelEvents::RESPONSE, [$this, 'onKernelResponse']);
         $this->registered = false;
-        $session = $request->getSession();
+        $token = $this->tokenStorage->getToken();
 
-        if ((null === $token = $this->tokenStorage->getToken()) || $this->trustResolver->isAnonymous($token)) {
-            if ($request->hasPreviousSession()) {
-                $session->remove($this->sessionKey);
+        if (null === $token || $this->trustResolver->isAnonymous($token)) {
+            if ($request->hasPreviousSession() && $request->hasSession()) {
+                $request->getSession()->remove($this->sessionKey);
             }
         } else {
-            $session->set($this->sessionKey, serialize($token));
+            $request->getSession()->set($this->sessionKey, serialize($token));
 
             if (null !== $this->logger) {
                 $this->logger->debug('Stored the security token in the session.', ['key' => $this->sessionKey]);
diff --git a/src/Symfony/Component/Security/Http/HttpUtils.php b/src/Symfony/Component/Security/Http/HttpUtils.php
index b70ba80b78..b31117a06f 100644
--- a/src/Symfony/Component/Security/Http/HttpUtils.php
+++ b/src/Symfony/Component/Security/Http/HttpUtils.php
@@ -87,7 +87,7 @@ class HttpUtils
         static $setSession;
 
         if (null === $setSession) {
-            $setSession = \Closure::bind(function ($newRequest, $request) { $newRequest->session = $request->session; }, null, Request::class);
+            $setSession = \Closure::bind(static function ($newRequest, $request) { $newRequest->session = $request->session; }, null, Request::class);
         }
         $setSession($newRequest, $request);
 
diff --git a/src/Symfony/Component/Yaml/Parser.php b/src/Symfony/Component/Yaml/Parser.php
index 4a84b39521..c117ee470f 100644
--- a/src/Symfony/Component/Yaml/Parser.php
+++ b/src/Symfony/Component/Yaml/Parser.php
@@ -386,6 +386,9 @@ class Parser
                     $value = '';
 
                     foreach ($this->lines as $line) {
+                        if ('' !== ltrim($line) && '#' === ltrim($line)[0]) {
+                            continue;
+                        }
                         // If the indentation is not consistent at offset 0, it is to be considered as a ParseError
                         if (0 === $this->offset && !$deprecatedUsage && isset($line[0]) && ' ' === $line[0]) {
                             throw new ParseException('Unable to parse.', $this->getRealCurrentLineNb() + 1, $this->currentLine, $this->filename);
diff --git a/src/Symfony/Component/Yaml/Tests/ParserTest.php b/src/Symfony/Component/Yaml/Tests/ParserTest.php
index 1bfd22cfe3..1626b54cd3 100644
--- a/src/Symfony/Component/Yaml/Tests/ParserTest.php
+++ b/src/Symfony/Component/Yaml/Tests/ParserTest.php
@@ -2152,6 +2152,18 @@ YAML;
 
         return $tests;
     }
+
+    public function testMultiLineComment()
+    {
+        $yaml = <<<YAML
+parameters:
+    abc
+
+# Comment 
+YAML;
+
+        $this->assertSame(['parameters' => 'abc'], $this->parser->parse($yaml));
+    }
 }
 
 class B