#3123 - Global D8 container is not available during container rebuild.

src/Drupal/DrupalKernel.php

@@ -1,6 +1,7 @@
 <?php
 namespace Drush\Drupal;
 
+use Drupal\Core\Site\Settings;
 use Drush\Log\LogLevel;
 use Drupal\Core\DrupalKernel as DrupalDrupalKernel;
 use Drupal\Core\DependencyInjection\ServiceModifierInterface;
@@ -45,6 +46,19 @@ protected function initializeContainer()
         $container_definition = $this->getCachedContainerDefinition();
 
         if ($this->shouldDrushInvalidateContainer()) {
+            // Normally when the container is being rebuilt, the existing
+            // container is still available for use until the newly built one
+            // replaces it. Certain contrib modules rely on services (like State
+            // or the config factory) being available for things like defining
+            // event subscriptions.
+            // @see https://github.com/drush-ops/drush/issues/3123
+            if (isset($container_definition)) {
+                $class = Settings::get('container_base_class', '\Drupal\Core\DependencyInjection\Container');
+                $container = new $class($container_definition);
+                $this->attachSynthetic($container);
+                \Drupal::setContainer($container);
+            }
+
             $this->invalidateContainer();
         }
         return parent::initializeContainer();

tests/containerTest.php

@@ -0,0 +1,63 @@
+<?php
+
+namespace Unish;
+
+use Webmozart\PathUtil\Path;
+
+/**
+ * Tests the Drush override of DrupalKernel.
+ *
+ * @group base
+ *
+ * @see https://github.com/drush-ops/drush/issues/3123
+ */
+class containerTest extends CommandUnishTestCase {
+
+    /**
+     * Tests that the existing container is available while Drush rebuilds it.
+     */
+    public function testContainer() {
+        $this->setUpDrupal(1, TRUE);
+        $root = $this->webroot();
+        $options = array(
+            'root' => $root,
+            'uri' => $this->getUri(),
+            'yes' => NULL,
+        );
+
+      // Copy the 'woot' module over to the Drupal site we just set up.
+      $this->setupModulesForTests($root);
+
+      // Enable our module.
+      $this->drush('pm-enable', ['woot'], $options);
+
+      // Set up for a config import with just one small piece.
+      $this->drush('config-export', array(), $options);
+      $this->drush('config-set', array('system.site', 'name', 'config_test'), $options);
+
+      // Trigger the container rebuild we need.
+      $this->drush('cr', [], $options);
+      $this->drush('cron', [], $options);
+
+      // If the event was registered successfully, then upon a config import, we
+      // should get the error message.
+      $this->drush('config-import', [], $options, NULL, NULL, CommandUnishTestCase::EXIT_ERROR);
+      $this->assertContains("woot config error", $this->getErrorOutput(), 'Event was successfully registered.');
+    }
+
+    /**
+     * Sets up the woot module for the test.
+     *
+     * @param string $root
+     *   The web root.
+     */
+    public function setupModulesForTests($root) {
+        $wootModule = Path::join(__DIR__, '/resources/modules/d8/woot');
+        // We install into Unish so that we aren't cleaned up. That causes
+        // container to go invalid after tearDownAfterClass().
+        $targetDir = Path::join($root, 'modules/unish/woot');
+        $this->mkdir($targetDir);
+        $this->recursive_copy($wootModule, $targetDir);
+    }
+
+}

tests/resources/modules/d8/woot/src/EventSubscriber/ConfigSubscriber.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace Drupal\woot\EventSubscriber;
+
+use Drupal\Core\Config\ConfigEvents;
+use Drupal\Core\Config\ConfigImporterEvent;
+use Drupal\Core\Config\ConfigImportValidateEventSubscriberBase;
+
+/**
+ * Subscribes to Symfony events and maps them to Rules events.
+ */
+class ConfigSubscriber extends ConfigImportValidateEventSubscriberBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getSubscribedEvents() {
+    $events = [];
+
+    // In this example, we would use information from the State API to determine
+    // what events we should subscribe to. Suffice it to say we trust that the
+    // State API works correctly, so we're only going to check if the service is
+    // available here to make our point.
+    if (\Drupal::hasService('state')) {
+      $events[ConfigEvents::IMPORT_VALIDATE][] = 'onConfigImporterValidate';
+    }
+
+    return $events;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function onConfigImporterValidate(ConfigImporterEvent $event) {
+    // Always log an error.
+    $importer = $event->getConfigImporter();
+    $importer->logError($this->t('woot config error'));
+  }
+
+}

tests/resources/modules/d8/woot/woot.services.yml

@@ -0,0 +1,5 @@
+services:
+  config.config_subscriber:
+    class: Drupal\woot\EventSubscriber\ConfigSubscriber
+    tags:
+      - { name: event_subscriber }