Merge branch '4.4'

* 4.4:
  [HttpFoundation][FrameworkBundle] allow configuring the session handler with a DSN
  [Validator] Add AutoMapping constraint to enable or disable auto-validation
  [DI] Fix "!tagged" related upgrade/changelog notes

Author: fabpot

CHANGELOG.md

@@ -38,6 +38,7 @@ CHANGELOG
  * Added sort option for `translation:update` command.
  * [BC Break] The `framework.messenger.routing.senders` config key is not deep merged anymore.
  * Added `secrets:*` commands and `%env(secret:...)%` processor to deal with secrets seamlessly.
+ * Made `framework.session.handler_id` accept a DSN
 
 4.3.0
 -----

DependencyInjection/FrameworkExtension.php

@@ -248,6 +248,9 @@ public function load(array $configs, ContainerBuilder $container)
             }
         }
 
+        // register cache before session so both can share the connection services
+        $this->registerCacheConfiguration($config['cache'], $container);
+
         if ($this->isConfigEnabled($container, $config['session'])) {
             if (!\extension_loaded('session')) {
                 throw new LogicException('Session support cannot be enabled as the session extension is not installed. See https://php.net/session.installation for instructions.');
@@ -328,7 +331,6 @@ public function load(array $configs, ContainerBuilder $container)
         $this->registerFragmentsConfiguration($config['fragments'], $container, $loader);
         $this->registerTranslatorConfiguration($config['translator'], $container, $loader, $config['default_locale']);
         $this->registerProfilerConfiguration($config['profiler'], $container, $loader);
-        $this->registerCacheConfiguration($config['cache'], $container);
         $this->registerWorkflowConfiguration($config['workflows'], $container, $loader);
         $this->registerDebugConfiguration($config['php_errors'], $container, $loader);
         $this->registerRouterConfiguration($config['router'], $container, $loader);
@@ -902,7 +904,18 @@ private function registerSessionConfiguration(array $config, ContainerBuilder $c
             $container->getDefinition('session.storage.native')->replaceArgument(1, null);
             $container->getDefinition('session.storage.php_bridge')->replaceArgument(0, null);
         } else {
-            $container->setAlias('session.handler', $config['handler_id'])->setPrivate(true);
+            $container->resolveEnvPlaceholders($config['handler_id'], null, $usedEnvs);
+
+            if ($usedEnvs || preg_match('#^[a-z]++://#', $config['handler_id'])) {
+                $id = '.cache_connection.'.ContainerBuilder::hash($config['handler_id']);
+
+                $container->getDefinition('session.abstract_handler')
+                    ->replaceArgument(0, $container->hasDefinition($id) ? new Reference($id) : $config['handler_id']);
+
+                $container->setAlias('session.handler', 'session.abstract_handler')->setPrivate(true);
+            } else {
+                $container->setAlias('session.handler', $config['handler_id'])->setPrivate(true);
+            }
         }
 
         $container->setParameter('session.save_path', $config['save_path']);

Resources/config/session.xml

@@ -56,6 +56,11 @@
             </argument>
         </service>
 
+        <service id="session.abstract_handler" class="Symfony\Component\HttpFoundation\Session\Storage\Handler\AbstractSessionHandler">
+            <factory class="Symfony\Component\HttpFoundation\Session\Storage\Handler\SessionHandlerFactory" method="createHandler" />
+            <argument />
+        </service>
+
         <service id="session_listener" class="Symfony\Component\HttpKernel\EventListener\SessionListener">
             <tag name="kernel.event_subscriber" />
             <argument type="service_locator">