Update to Drupal 8.2.0. For more information, see https://www.drupal.org/project/drupal/releases/8.2.0

core/modules/migrate/src/Plugin/MigrateSourcePluginManager.php

@@ -0,0 +1,80 @@
+<?php
+
+namespace Drupal\migrate\Plugin;
+
+use Drupal\Core\Cache\CacheBackendInterface;
+use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\migrate\Plugin\Discovery\AnnotatedClassDiscoveryAutomatedProviders;
+use Drupal\Core\Plugin\Discovery\ContainerDerivativeDiscoveryDecorator;
+use Drupal\migrate\Plugin\Discovery\ProviderFilterDecorator;
+
+/**
+ * Plugin manager for migrate source plugins.
+ *
+ * @see \Drupal\migrate\Plugin\MigrateSourceInterface
+ * @see \Drupal\migrate\Plugin\source\SourcePluginBase
+ * @see \Drupal\migrate\Annotation\MigrateSource
+ * @see plugin_api
+ *
+ * @ingroup migration
+ */
+class MigrateSourcePluginManager extends MigratePluginManager {
+
+  /**
+   * The class loader.
+   *
+   * @var object
+   */
+  protected $classLoader;
+
+  /**
+   * MigrateSourcePluginManager constructor.
+   *
+   * @param string $type
+   *   The type of the plugin: row, source, process, destination, entity_field,
+   *   id_map.
+   * @param \Traversable $namespaces
+   *   An object that implements \Traversable which contains the root paths
+   *   keyed by the corresponding namespace to look for plugin implementations.
+   * @param \Drupal\Core\Cache\CacheBackendInterface $cache_backend
+   *   Cache backend instance to use.
+   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
+   *   The module handler to invoke the alter hook with.
+   */
+  public function __construct($type, \Traversable $namespaces, CacheBackendInterface $cache_backend, ModuleHandlerInterface $module_handler) {
+    parent::__construct($type, $namespaces, $cache_backend, $module_handler, 'Drupal\migrate\Annotation\MigrateSource');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getDiscovery() {
+    if (!$this->discovery) {
+      $discovery = new AnnotatedClassDiscoveryAutomatedProviders($this->subdir, $this->namespaces, $this->pluginDefinitionAnnotationName, $this->additionalAnnotationNamespaces);
+      $this->discovery = new ContainerDerivativeDiscoveryDecorator($discovery);
+    }
+    return $this->discovery;
+  }
+
+  /**
+   * Finds plugin definitions.
+   *
+   * @return array
+   *   List of definitions to store in cache.
+   *
+   * @todo This is a temporary solution to the fact that migration source
+   *   plugins have more than one provider. This functionality will be moved to
+   *   core in https://www.drupal.org/node/2786355.
+   */
+  protected function findDefinitions() {
+    $definitions = $this->getDiscovery()->getDefinitions();
+    foreach ($definitions as $plugin_id => &$definition) {
+      $this->processDefinition($definition, $plugin_id);
+    }
+    $this->alterDefinitions($definitions);
+    return ProviderFilterDecorator::filterDefinitions($definitions, function ($provider) {
+      return $this->providerExists($provider);
+    });
+  }
+
+}