updated core from 8.4 to 8.5 : bug with login_destination

core/modules/migrate/migrate.api.php

@@ -10,78 +10,81 @@ use Drupal\migrate\Plugin\MigrateSourceInterface;
 use Drupal\migrate\Row;
 
 /**
- * @defgroup migration Migration API
+ * @defgroup migration Migrate API
  * @{
- * Overview of the Migration API, which migrates data into Drupal.
+ * Overview of the Migrate API, which migrates data into Drupal.
  *
- * @section overview Overview of migration
+ * @section overview Overview of a migration
  * Migration is an
  * @link http://wikipedia.org/wiki/Extract,_transform,_load Extract, Transform, Load @endlink
- * (ETL) process. In the Drupal migration API the extract phase is called
- * "source", the transform phase is called "process", and the load phase is
- * called "destination". It is important to understand that the "load" in ETL
- * means to load data into storage, while traditionally Drupal uses "load" to
- * mean load data from storage into memory.
+ * (ETL) process. In the Drupal Migrate API, the extract phase is called
+ * 'source', the transform phase is called 'process', and the load phase is
+ * called 'destination'. It is important to understand that the term 'load' in
+ * ETL refers to loading data into the storage while in a typical Drupal context
+ * the term 'load' refers to loading data from storage.
  *
  * In the source phase, a set of data, called the row, is retrieved from the
- * data source, typically a database but it can be a CSV, JSON or XML file. The
- * row is sent to the process phase where it is transformed as needed by the
- * destination, or marked to be skipped. Processing can also determine that a
- * stub needs to be created, for example, if a term has a parent term that does
- * not yet exist. After processing the transformed row is passed to the
- * destination phase where it is loaded (saved) into the Drupal 8 site.
+ * data source. The data can be migrated from a database, loaded from a file
+ * (for example CSV, JSON or XML) or fetched from a web service (for example RSS
+ * or REST). The row is sent to the process phase where it is transformed as
+ * needed or marked to be skipped. Processing can also determine if a 'stub'
+ * needs to be created. For example, if a term has a parent term which hasn't
+ * been migrated yet, a stub term is created so that the parent relation can be
+ * established, and the stub is updated at a later point. After processing, the
+ * transformed row is passed to the destination phase where it is loaded (saved)
+ * into the target Drupal site.
  *
- * The ETL process is configured by the migration plugin. The different phases:
- * source, process, and destination are also plugins, and are managed by the
- * Migration plugin. So there are four types of plugins in the migration
- * process: migration, source, process and destination.
+ * Migrate API uses the Drupal plugin system for many different purposes. Most
+ * importantly, the overall ETL process is defined as a migration plugin and the
+ * three phases (source, process and destination) have their own plugin types.
  *
- * @section sec_migrations Migration plugins
+ * @section sec_migrations Migrate API migration plugins
  * Migration plugin definitions are stored in a module's 'migrations' directory.
- * For backwards compatibility we also scan the 'migration_templates' directory.
- * Examples of migration plugin definitions can be found in
- * 'core/modules/action/migration_templates'. The plugin class is
- * \Drupal\migrate\Plugin\Migration, with interface
+ * The plugin class is \Drupal\migrate\Plugin\Migration, with interface
  * \Drupal\migrate\Plugin\MigrationInterface. Migration plugins are managed by
  * the \Drupal\migrate\Plugin\MigrationPluginManager class. Migration plugins
  * are only available if the providers of their source plugins are installed.
  *
- * @section sec_source Source plugins
- * Migration source plugins implement
+ * @link https://www.drupal.org/docs/8/api/migrate-api/migrate-destination-plugins-examples Example migrations in Migrate API handbook. @endlink
+ *
+ * @section sec_source Migrate API source plugins
+ * Migrate API source plugins implement
  * \Drupal\migrate\Plugin\MigrateSourceInterface and usually extend
  * \Drupal\migrate\Plugin\migrate\source\SourcePluginBase. They are annotated
- * with \Drupal\migrate\Annotation\MigrateSource annotation, and must be in
- * namespace subdirectory Plugin\migrate\source under the namespace of the
- * module that defines them. Migration source plugins are managed by the
- * \Drupal\migrate\Plugin\MigrateSourcePluginManager class. Source plugin
- * providers are determined by their and their parents namespaces.
+ * with \Drupal\migrate\Annotation\MigrateSource annotation and must be in
+ * namespace subdirectory 'Plugin\migrate\source' under the namespace of the
+ * module that defines them. Migrate API source plugins are managed by the
+ * \Drupal\migrate\Plugin\MigrateSourcePluginManager class.
  *
- * @section sec_process Process plugins
- * Migration process plugins implement
+ * @link https://api.drupal.org/api/drupal/namespace/Drupal!migrate!Plugin!migrate!source List of source plugins provided by the core Migrate module. @endlink
+ * @link https://www.drupal.org/docs/8/api/migrate-api/migrate-source-plugins Core and contributed source plugin usage examples in Migrate API handbook. @endlink
+ *
+ * @section sec_process Migrate API process plugins
+ * Migrate API process plugins implement
  * \Drupal\migrate\Plugin\MigrateProcessInterface and usually extend
- * \Drupal\migrate\ProcessPluginBase. They are annotated
- * with \Drupal\migrate\Annotation\MigrateProcessPlugin annotation, and must be
- * in namespace subdirectory Plugin\migrate\process under the namespace of the
- * module that defines them. Migration process plugins are managed by the
- * \Drupal\migrate\Plugin\MigratePluginManager class. The Migrate module
- * provides process plugins for common operations (setting default values,
- * mapping values, etc.).
+ * \Drupal\migrate\ProcessPluginBase. They are annotated with
+ * \Drupal\migrate\Annotation\MigrateProcessPlugin annotation and must be in
+ * namespace subdirectory 'Plugin\migrate\process' under the namespace of the
+ * module that defines them. Migrate API process plugins are managed by the
+ * \Drupal\migrate\Plugin\MigratePluginManager class.
  *
- * @section sec_destination Destination plugins
- * Migration destination plugins implement
+ * @link https://api.drupal.org/api/drupal/namespace/Drupal!migrate!Plugin!migrate!process List of process plugins for common operations provided by the core Migrate module. @endlink
+ *
+ * @section sec_destination Migrate API destination plugins
+ * Migrate API destination plugins implement
  * \Drupal\migrate\Plugin\MigrateDestinationInterface and usually extend
  * \Drupal\migrate\Plugin\migrate\destination\DestinationBase. They are
- * annotated with \Drupal\migrate\Annotation\MigrateDestination annotation, and
- * must be in namespace subdirectory Plugin\migrate\destination under the
- * namespace of the module that defines them. Migration destination plugins
+ * annotated with \Drupal\migrate\Annotation\MigrateDestination annotation and
+ * must be in namespace subdirectory 'Plugin\migrate\destination' under the
+ * namespace of the module that defines them. Migrate API destination plugins
  * are managed by the \Drupal\migrate\Plugin\MigrateDestinationPluginManager
- * class. The Migrate module provides destination plugins for Drupal core
- * objects (configuration and entity).
+ * class.
  *
- * @section sec_more_info More information
- * @link https://www.drupal.org/node/2127611 Migration API documentation. @endlink
+ * @link https://api.drupal.org/api/drupal/namespace/Drupal!migrate!Plugin!migrate!destination List of destination plugins for Drupal configuration and content entities provided by the core Migrate module. @endlink
  *
- * @see update_api
+ * @section sec_more_info Documentation handbooks
+ * @link https://www.drupal.org/docs/8/api/migrate-api Migrate API handbook. @endlink
+ * @link https://www.drupal.org/docs/8/upgrade Upgrading to Drupal 8 handbook. @endlink
  * @}
  */
 
@@ -99,6 +102,13 @@ use Drupal\migrate\Row;
  *
  * hook_migrate_MIGRATION_ID_prepare_row() is also available.
  *
+ * @param \Drupal\migrate\Row $row
+ *   The row being imported.
+ * @param \Drupal\migrate\Plugin\MigrateSourceInterface $source
+ *   The source migration.
+ * @param \Drupal\migrate\Plugin\MigrationInterface $migration
+ *   The current migration.
+ *
  * @ingroup migration
  */
 function hook_migrate_prepare_row(Row $row, MigrateSourceInterface $source, MigrationInterface $migration) {
@@ -110,6 +120,28 @@ function hook_migrate_prepare_row(Row $row, MigrateSourceInterface $source, Migr
   }
 }
 
+/**
+ * Allows adding data to a row for a migration with the specified ID.
+ *
+ * This provides the same functionality as hook_migrate_prepare_row() but
+ * removes the need to check the value of $migration->id().
+ *
+ * @param \Drupal\migrate\Row $row
+ *   The row being imported.
+ * @param \Drupal\migrate\Plugin\MigrateSourceInterface $source
+ *   The source migration.
+ * @param \Drupal\migrate\Plugin\MigrationInterface $migration
+ *   The current migration.
+ *
+ * @ingroup migration
+ */
+function hook_migrate_MIGRATION_ID_prepare_row(Row $row, MigrateSourceInterface $source, MigrationInterface $migration) {
+  $value = $source->getDatabase()->query('SELECT value FROM {variable} WHERE name = :name', [':name' => 'mymodule_filter_foo_' . $row->getSourceProperty('format')])->fetchField();
+  if ($value) {
+    $row->setSourceProperty('settings:mymodule:foo', unserialize($value));
+  }
+}
+
 /**
  * Allows altering the list of discovered migration plugins.
  *

core/modules/migrate/migrate.info.yml

@@ -1,12 +1,12 @@
 name: Migrate
 type: module
 description: 'Handles migrations'
-package: Core (Experimental)
+package: Migration
 # version: VERSION
 # core: 8.x
 
-# Information added by Drupal.org packaging script on 2018-01-03
-version: '8.4.4'
+# Information added by Drupal.org packaging script on 2018-03-07
+version: '8.5.0'
 core: '8.x'
 project: 'drupal'
-datestamp: 1515021228
+datestamp: 1520457825

core/modules/migrate/src/Audit/AuditException.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace Drupal\migrate\Audit;
+
+use Drupal\migrate\Plugin\MigrationInterface;
+
+/**
+ * Defines an exception to throw if an error occurs during a migration audit.
+ */
+class AuditException extends \RuntimeException {
+
+  /**
+   * AuditException constructor.
+   *
+   * @param \Drupal\migrate\Plugin\MigrationInterface $migration
+   *   The migration that caused the exception.
+   * @param string $message
+   *   The reason the audit failed.
+   * @param \Exception $previous
+   *   (optional) The previous exception.
+   */
+  public function __construct(MigrationInterface $migration, $message, \Exception $previous = NULL) {
+    $message = sprintf('Cannot audit migration %s: %s', $migration->id(), $message);
+    parent::__construct($message, 0, $previous);
+  }
+
+}

core/modules/migrate/src/Audit/AuditResult.php

@@ -0,0 +1,146 @@
+<?php
+
+namespace Drupal\migrate\Audit;
+
+use Drupal\Component\Render\MarkupInterface;
+use Drupal\migrate\Plugin\MigrationInterface;
+
+/**
+ * Encapsulates the result of a migration audit.
+ */
+class AuditResult implements MarkupInterface, \Countable {
+
+  /**
+   * The audited migration.
+   *
+   * @var \Drupal\migrate\Plugin\MigrationInterface
+   */
+  protected $migration;
+
+  /**
+   * The result of the audit (TRUE if passed, FALSE otherwise).
+   *
+   * @var bool
+   */
+  protected $status;
+
+  /**
+   * The reasons why the migration passed or failed the audit.
+   *
+   * @var string[]
+   */
+  protected $reasons = [];
+
+  /**
+   * AuditResult constructor.
+   *
+   * @param \Drupal\migrate\Plugin\MigrationInterface $migration
+   *   The audited migration.
+   * @param bool $status
+   *   The result of the audit (TRUE if passed, FALSE otherwise).
+   * @param string[] $reasons
+   *   (optional) The reasons why the migration passed or failed the audit.
+   */
+  public function __construct(MigrationInterface $migration, $status, array $reasons = []) {
+    if (!is_bool($status)) {
+      throw new \InvalidArgumentException('Audit results must have a boolean status.');
+    }
+    $this->migration = $migration;
+    $this->status = $status;
+    array_walk($reasons, [$this, 'addReason']);
+  }
+
+  /**
+   * Returns the audited migration.
+   *
+   * @return \Drupal\migrate\Plugin\MigrationInterface
+   *   The audited migration.
+   */
+  public function getMigration() {
+    return $this->migration;
+  }
+
+  /**
+   * Returns the boolean result of the audit.
+   *
+   * @return bool
+   *   The result of the audit. TRUE if the migration passed the audit, FALSE
+   *   otherwise.
+   */
+  public function passed() {
+    return $this->status;
+  }
+
+  /**
+   * Adds a reason why the migration passed or failed the audit.
+   *
+   * @param string|object $reason
+   *   The reason to add. Can be a string or a string-castable object.
+   *
+   * @return $this
+   */
+  public function addReason($reason) {
+    array_push($this->reasons, (string) $reason);
+    return $this;
+  }
+
+  /**
+   * Creates a passing audit result for a migration.
+   *
+   * @param \Drupal\migrate\Plugin\MigrationInterface $migration
+   *   The audited migration.
+   * @param string[] $reasons
+   *   (optional) The reasons why the migration passed the audit.
+   *
+   * @return static
+   */
+  public static function pass(MigrationInterface $migration, array $reasons = []) {
+    return new static($migration, TRUE, $reasons);
+  }
+
+  /**
+   * Creates a failing audit result for a migration.
+   *
+   * @param \Drupal\migrate\Plugin\MigrationInterface $migration
+   *   The audited migration.
+   * @param array $reasons
+   *   (optional) The reasons why the migration failed the audit.
+   *
+   * @return static
+   */
+  public static function fail(MigrationInterface $migration, array $reasons = []) {
+    return new static($migration, FALSE, $reasons);
+  }
+
+  /**
+   * Implements \Countable::count() for Twig template compatibility.
+   *
+   * @return int
+   *
+   * @see \Drupal\Component\Render\MarkupInterface
+   */
+  public function count() {
+    return count($this->reasons);
+  }
+
+  /**
+   * Returns the reasons the migration passed or failed, as a string.
+   *
+   * @return string
+   *
+   * @see \Drupal\Component\Render\MarkupInterface
+   */
+  public function __toString() {
+    return implode("\n", $this->reasons);
+  }
+
+  /**
+   * Returns the reasons the migration passed or failed, for JSON serialization.
+   *
+   * @return string[]
+   */
+  public function jsonSerialize() {
+    return $this->reasons;
+  }
+
+}

core/modules/migrate/src/Audit/AuditorInterface.php

@@ -0,0 +1,42 @@
+<?php
+
+namespace Drupal\migrate\Audit;
+
+use Drupal\migrate\Plugin\MigrationInterface;
+
+/**
+ * Defines an interface for migration auditors.
+ *
+ * A migration auditor is a class which can examine a migration to determine if
+ * it will cause conflicts with data already existing in the destination system.
+ * What kind of auditing it does, and how it does it, is up to the implementing
+ * class.
+ */
+interface AuditorInterface {
+
+  /**
+   * Audits a migration.
+   *
+   * @param \Drupal\migrate\Plugin\MigrationInterface $migration
+   *   The migration to audit.
+   *
+   * @throws \Drupal\migrate\Audit\AuditException
+   *   If the audit fails.
+   *
+   * @return \Drupal\migrate\Audit\AuditResult
+   *   The result of the audit.
+   */
+  public function audit(MigrationInterface $migration);
+
+  /**
+   * Audits a set of migrations.
+   *
+   * @param \Drupal\migrate\Plugin\MigrationInterface[] $migrations
+   *   The migrations to audit.
+   *
+   * @return \Drupal\migrate\Audit\AuditResult[]
+   *   The audit results, keyed by migration ID.
+   */
+  public function auditMultiple(array $migrations);
+
+}

core/modules/migrate/src/Audit/HighestIdInterface.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace Drupal\migrate\Audit;
+
+/**
+ * Defines an interface for destination and ID maps which track a highest ID.
+ *
+ * When implemented by destination plugins, getHighestId() should return the
+ * highest ID of the destination entity type that exists in the system. So, for
+ * example, the entity:node plugin should return the highest node ID that
+ * exists, regardless of whether it was created by a migration.
+ *
+ * When implemented by an ID map, getHighestId() should return the highest
+ * migrated ID of the destination entity type.
+ */
+interface HighestIdInterface {
+
+  /**
+   * Returns the highest ID tracked by the implementing plugin.
+   *
+   * @return int
+   *   The highest ID.
+   */
+  public function getHighestId();
+
+}

core/modules/migrate/src/Audit/IdAuditor.php

@@ -0,0 +1,58 @@
+<?php
+
+namespace Drupal\migrate\Audit;
+
+use Drupal\Core\StringTranslation\StringTranslationTrait;
+use Drupal\migrate\Plugin\MigrationInterface;
+
+/**
+ * Audits migrations that create content entities in the destination system.
+ */
+class IdAuditor implements AuditorInterface {
+
+  use StringTranslationTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function audit(MigrationInterface $migration) {
+    // If the migration does not opt into auditing, it passes.
+    if (!$migration->isAuditable()) {
+      return AuditResult::pass($migration);
+    }
+
+    $interface = HighestIdInterface::class;
+
+    $destination = $migration->getDestinationPlugin();
+    if (!$destination instanceof HighestIdInterface) {
+      throw new AuditException($migration, "Destination does not implement $interface");
+    }
+
+    $id_map = $migration->getIdMap();
+    if (!$id_map instanceof HighestIdInterface) {
+      throw new AuditException($migration, "ID map does not implement $interface");
+    }
+
+    if ($destination->getHighestId() > $id_map->getHighestId()) {
+      return AuditResult::fail($migration, [
+        $this->t('The destination system contains data which was not created by a migration.'),
+      ]);
+    }
+    return AuditResult::pass($migration);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function auditMultiple(array $migrations) {
+    $conflicts = [];
+
+    foreach ($migrations as $migration) {
+      $migration_id = $migration->getPluginId();
+      $conflicts[$migration_id] = $this->audit($migration);
+    }
+    ksort($conflicts);
+    return $conflicts;
+  }
+
+}

core/modules/migrate/src/Exception/RequirementsException.php

@@ -5,7 +5,7 @@ namespace Drupal\migrate\Exception;
 use Exception;
 
 /**
- * Defines an
+ * Defines an exception thrown when a migration does not meet the requirements.
  *
  * @see \Drupal\migrate\Plugin\RequirementsInterface
  */

core/modules/migrate/src/MigrateExecutable.php

@@ -96,16 +96,16 @@ class MigrateExecutable implements MigrateExecutableInterface {
    * @param \Drupal\migrate\Plugin\MigrationInterface $migration
    *   The migration to run.
    * @param \Drupal\migrate\MigrateMessageInterface $message
-   *   The migrate message service.
+   *   (optional) The migrate message service.
    * @param \Symfony\Component\EventDispatcher\EventDispatcherInterface $event_dispatcher
-   *   The event dispatcher.
+   *   (optional) The event dispatcher.
    *
    * @throws \Drupal\migrate\MigrateException
    */
-  public function __construct(MigrationInterface $migration, MigrateMessageInterface $message, EventDispatcherInterface $event_dispatcher = NULL) {
+  public function __construct(MigrationInterface $migration, MigrateMessageInterface $message = NULL, EventDispatcherInterface $event_dispatcher = NULL) {
     $this->migration = $migration;
-    $this->message = $message;
-    $this->migration->getIdMap()->setMessage($message);
+    $this->message = $message ?: new MigrateMessage();
+    $this->migration->getIdMap()->setMessage($this->message);
     $this->eventDispatcher = $event_dispatcher;
     // Record the memory limit in bytes
     $limit = trim(ini_get('memory_limit'));

core/modules/migrate/src/Plugin/Exception/BadPluginDefinitionException.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace Drupal\migrate\Plugin\Exception;
+
+use Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException;
+
+/**
+ * Defines a class for bad plugin definition exceptions.
+ */
+class BadPluginDefinitionException extends InvalidPluginDefinitionException {
+
+  /**
+   * Constructs a BadPluginDefinitionException.
+   *
+   * For the remaining parameters see \Exception.
+   *
+   * @param string $plugin_id
+   *   The plugin ID of the mapper.
+   * @param string $property
+   *   The name of the property that is missing from the plugin.
+   *
+   * @see \Exception
+   */
+  public function __construct($plugin_id, $property, $code = 0, \Exception $previous = NULL) {
+    $message = sprintf('The %s plugin must define the %s property.', $plugin_id, $property);
+    parent::__construct($plugin_id, $message, $code, $previous);
+  }
+
+}

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

@@ -154,6 +154,17 @@ class Migration extends PluginBase implements MigrationInterface, RequirementsIn
    */
   protected $migration_tags = [];
 
+  /**
+   * Whether the migration is auditable.
+   *
+   * If set to TRUE, the migration's IDs will be audited. This means that, if
+   * the highest destination ID is greater than the highest source ID, a warning
+   * will be displayed that entities might be overwritten.
+   *
+   * @var bool
+   */
+  protected $audit = FALSE;
+
   /**
    * These migrations, if run, must be executed before this migration.
    *
@@ -677,4 +688,11 @@ class Migration extends PluginBase implements MigrationInterface, RequirementsIn
     return $this->migration_tags;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function isAuditable() {
+    return (bool) $this->audit;
+  }
+
 }

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

@@ -25,6 +25,9 @@ trait MigrationDeriverTrait {
       'destination' => [
         'plugin' => 'null',
       ],
+      'idMap' => [
+        'plugin' => 'null',
+      ],
     ];
     return \Drupal::service('plugin.manager.migration')->createStubMigration($definition)->getSourcePlugin();
   }

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

@@ -322,4 +322,11 @@ interface MigrationInterface extends PluginInspectionInterface, DerivativeInspec
    */
   public function getMigrationTags();
 
+  /**
+   * Indicates if the migration is auditable.
+   *
+   * @return bool
+   */
+  public function isAuditable();
+
 }

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

@@ -60,11 +60,22 @@ class MigrationPluginManager extends DefaultPluginManager implements MigrationPl
   }
 
   /**
-   * {@inheritdoc}
+   * Gets the plugin discovery.
+   *
+   * This method overrides DefaultPluginManager::getDiscovery() in order to
+   * search for migration configurations in the MODULENAME/migrations and
+   * MODULENAME/migration_templates directories. Throws a deprecation notice if
+   * the MODULENAME/migration_templates directory exists.
    */
   protected function getDiscovery() {
     if (!isset($this->discovery)) {
       $directories = array_map(function ($directory) {
+        // Check for use of the @deprecated /migration_templates directory.
+        // @todo Remove use of /migration_templates in Drupal 9.0.0.
+        if (is_dir($directory . '/migration_templates')) {
+          @trigger_error('Use of the /migration_templates directory to store migration configuration files is deprecated in Drupal 8.1.0 and will be removed before Drupal 9.0.0. See https://www.drupal.org/node/2920988.', E_USER_DEPRECATED);
+        }
+        // But still accept configurations found in /migration_templates.
         return [$directory . '/migration_templates', $directory . '/migrations'];
       }, $this->moduleHandler->getModuleDirectories());
 
@@ -116,13 +127,7 @@ class MigrationPluginManager extends DefaultPluginManager implements MigrationPl
   }
 
   /**
-   * Create migrations given a tag.
-   *
-   * @param string $tag
-   *   A migration tag we want to filter by.
-   *
-   * @return array|\Drupal\migrate\Plugin\MigrationInterface[]
-   *   An array of migration objects with the given tag.
+   * {@inheritdoc}
    */
   public function createInstancesByTag($tag) {
     $migrations = array_filter($this->getDefinitions(), function ($migration) use ($tag) {

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

@@ -40,4 +40,15 @@ interface MigrationPluginManagerInterface extends PluginManagerInterface {
    */
   public function createStubMigration(array $definition);
 
+  /**
+   * Create migrations given a tag.
+   *
+   * @param string $tag
+   *   A migration tag we want to filter by.
+   *
+   * @return array|\Drupal\migrate\Plugin\MigrationInterface[]
+   *   An array of migration objects with the given tag.
+   */
+  public function createInstancesByTag($tag);
+
 }

core/modules/migrate/src/Plugin/migrate/destination/ComponentEntityDisplayBase.php

@@ -6,7 +6,14 @@ use Drupal\migrate\Plugin\MigrationInterface;
 use Drupal\migrate\Row;
 
 /**
- * Defines the base abstract class for component entity display.
+ * Provides a destination plugin for migrating entity display components.
+ *
+ * Display modes provide different presentations for viewing ('view modes') or
+ * editing ('form modes') content. This destination plugin is an abstract base
+ * class for migrating fields and other components into view and form modes.
+ *
+ * @see \Drupal\migrate\Plugin\migrate\destination\PerComponentEntityDisplay
+ * @see \Drupal\migrate\Plugin\migrate\destination\PerComponentEntityFormDisplay
  */
 abstract class ComponentEntityDisplayBase extends DestinationBase {
 

core/modules/migrate/src/Plugin/migrate/destination/DestinationBase.php

@@ -12,7 +12,12 @@ use Drupal\migrate\Plugin\RequirementsInterface;
 /**
  * Base class for migrate destination classes.
  *
- * @see \Drupal\migrate\Plugin\MigrateDestinationInterface
+ * Migrate destination plugins perfom the import operation of the migration.
+ * Destination plugins extend this abstract base class. A destination plugin
+ * must implement at least fields(), getIds() and import() methods. Destination
+ * plugins can also support rollback operations. For more
+ * information, refer to \Drupal\migrate\Plugin\MigrateDestinationInterface.
+ *
  * @see \Drupal\migrate\Plugin\MigrateDestinationPluginManager
  * @see \Drupal\migrate\Annotation\MigrateDestination
  * @see plugin_api

core/modules/migrate/src/Plugin/migrate/destination/Entity.php

@@ -11,7 +11,48 @@ use Drupal\migrate\Row;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
- * Provides entity destination plugin.
+ * Provides a generic destination to import entities.
+ *
+ * Available configuration keys:
+ * - translations: (optional) Boolean, if TRUE, the destination will be
+ *   associated with the langcode provided by the source plugin. Defaults to
+ *   FALSE.
+ *
+ * Examples:
+ *
+ * @code
+ * source:
+ *   plugin: d7_node
+ * process:
+ *   nid: tnid
+ *   vid: vid
+ *   langcode: language
+ *   title: title
+ *   ...
+ *   revision_timestamp: timestamp
+ * destination:
+ *   plugin: entity:node
+ * @endcode
+ *
+ * This will save the processed, migrated row as a node.
+ *
+ * @code
+ * source:
+ *   plugin: d7_node
+ * process:
+ *   nid: tnid
+ *   vid: vid
+ *   langcode: language
+ *   title: title
+ *   ...
+ *   revision_timestamp: timestamp
+ * destination:
+ *   plugin: entity:node
+ *   translations: true
+ * @endcode
+ *
+ * This will save the processed, migrated row as a node with the relevant
+ * langcode because the translations configuration is set to "true".
  *
  * @MigrateDestination(
  *   id = "entity",
@@ -53,6 +94,10 @@ abstract class Entity extends DestinationBase implements ContainerFactoryPluginI
    *   The list of bundles this entity type has.
    */
   public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, EntityStorageInterface $storage, array $bundles) {
+    $plugin_definition += [
+      'label' => $storage->getEntityType()->getPluralLabel(),
+    ];
+
     parent::__construct($configuration, $plugin_id, $plugin_definition, $migration);
     $this->storage = $storage;
     $this->bundles = $bundles;

core/modules/migrate/src/Plugin/migrate/destination/EntityBaseFieldOverride.php

@@ -5,7 +5,42 @@ namespace Drupal\migrate\Plugin\migrate\destination;
 use Drupal\migrate\Row;
 
 /**
- * Provides entity base field override plugin.
+ * Provides entity base field override destination plugin.
+ *
+ * Base fields are non-configurable fields that always exist on a given entity
+ * type, like the 'title', 'created' and 'sticky' fields of the 'node' entity
+ * type. Some entity types can have bundles, for example the node content types.
+ * The base fields exist on all bundles but the bundles can override the
+ * definitions. For example, the label for node 'title' base field can be
+ * different on different content types.
+ *
+ * Example:
+ *
+ * The example below migrates the node 'sticky' settings for each content type.
+ * @code
+ * id: d6_node_setting_sticky
+ * label: Node type 'sticky' setting
+ * migration_tags:
+ *   - Drupal 6
+ * source:
+ *   plugin: d6_node_type
+ *   constants:
+ *     entity_type: node
+ *     field_name: sticky
+ * process:
+ *   entity_type: 'constants/entity_type'
+ *   bundle: type
+ *   field_name: 'constants/field_name'
+ *   label:
+ *     plugin: default_value
+ *     default_value: 'Sticky at the top of lists'
+ *   'default_value/0/value': 'options/sticky'
+ * destination:
+ *   plugin: entity:base_field_override
+ * migration_dependencies:
+ *   required:
+ *     - d6_node_type
+ * @endcode
  *
  * @MigrateDestination(
  *   id = "entity:base_field_override"

core/modules/migrate/src/Plugin/migrate/destination/EntityContentBase.php

@@ -9,6 +9,7 @@ use Drupal\Core\Entity\EntityStorageInterface;
 use Drupal\Core\Field\FieldTypePluginManagerInterface;
 use Drupal\Core\TypedData\TranslatableInterface;
 use Drupal\Core\TypedData\TypedDataInterface;
+use Drupal\migrate\Audit\HighestIdInterface;
 use Drupal\migrate\Plugin\MigrationInterface;
 use Drupal\migrate\MigrateException;
 use Drupal\migrate\Plugin\MigrateIdMapInterface;
@@ -16,9 +17,68 @@ use Drupal\migrate\Row;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
- * The destination class for all content entities lacking a specific class.
+ * Provides destination class for all content entities lacking a specific class.
+ *
+ * Available configuration keys:
+ * - translations: (optional) Boolean, indicates if the entity is translatable,
+ *   defaults to FALSE.
+ * - overwrite_properties: (optional) A list of properties that will be
+ *   overwritten if an entity with the same ID already exists. Any properties
+ *   that are not listed will not be overwritten.
+ *
+ * Example:
+ *
+ * The example below will create a 'node' entity of content type 'article'.
+ *
+ * The language of the source will be used because the configuration
+ * 'translations: true' was set. Without this configuration option the site's
+ * default language would be used.
+ *
+ * The example content type has fields 'title', 'body' and 'field_example'.
+ * The text format of the body field is defaulted to 'basic_html'. The example
+ * uses the EmbeddedDataSource source plugin for the sake of simplicity.
+ *
+ * If the migration is executed again in an update mode, any updates done in the
+ * destination Drupal site to the 'title' and 'body' fields would be overwritten
+ * with the original source values. Updates done to 'field_example' would be
+ * preserved because 'field_example' is not included in 'overwrite_properties'
+ * configuration.
+ * @code
+ * id: custom_article_migration
+ * label: Custom article migration
+ * source:
+ *   plugin: embedded_data
+ *   data_rows:
+ *     -
+ *       id: 1
+ *       langcode: 'fi'
+ *       title: 'Sivun otsikko'
+ *       field_example: 'Huhuu'
+ *       content: '<p>Hoi maailma</p>'
+ *   ids:
+ *     id:
+ *       type: integer
+ * process:
+ *   nid: id
+ *   langcode: langcode
+ *   title: title
+ *   field_example: field_example
+ *   'body/0/value': content
+ *   'body/0/format':
+ *     plugin: default_value
+ *     default_value: basic_html
+ * destination:
+ *   plugin: entity:node
+ *   default_bundle: article
+ *   translations: true
+ *   overwrite_properties:
+ *     - title
+ *     - body
+ * @endcode
+ *
+ * @see \Drupal\migrate\Plugin\migrate\destination\EntityRevision
  */
-class EntityContentBase extends Entity {
+class EntityContentBase extends Entity implements HighestIdInterface {
 
   /**
    * Entity manager.
@@ -111,12 +171,9 @@ class EntityContentBase extends Entity {
   }
 
   /**
-   * Get whether this destination is for translations.
-   *
-   * @return bool
-   *   Whether this destination is for translations.
+   * {@inheritdoc}
    */
-  protected function isTranslationDestination() {
+  public function isTranslationDestination() {
     return !empty($this->configuration['translations']);
   }
 
@@ -218,7 +275,7 @@ class EntityContentBase extends Entity {
       if ($field_definition->isRequired() && is_null($row->getDestinationProperty($field_name))) {
         // Use the configured default value for this specific field, if any.
         if ($default_value = $field_definition->getDefaultValueLiteral()) {
-          $values[] = $default_value;
+          $values = $default_value;
         }
         else {
           // Otherwise, ask the field type to generate a sample value.
@@ -294,4 +351,16 @@ class EntityContentBase extends Entity {
     ] + $field_definition->getSettings();
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function getHighestId() {
+    $values = $this->storage->getQuery()
+      ->accessCheck(FALSE)
+      ->sort($this->getKey('id'), 'DESC')
+      ->range(0, 1)
+      ->execute();
+    return (int) current($values);
+  }
+
 }

core/modules/migrate/src/Plugin/migrate/destination/EntityRevision.php

@@ -3,12 +3,107 @@
 namespace Drupal\migrate\Plugin\migrate\destination;
 
 use Drupal\Core\Entity\ContentEntityInterface;
+use Drupal\Core\Entity\EntityManagerInterface;
+use Drupal\Core\Entity\EntityStorageInterface;
+use Drupal\Core\Field\FieldTypePluginManagerInterface;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
 use Drupal\migrate\MigrateException;
+use Drupal\migrate\Plugin\MigrationInterface;
 use Drupal\migrate\Row;
 
 /**
  * Provides entity revision destination plugin.
  *
+ * Refer to the parent class for configuration keys:
+ * \Drupal\migrate\Plugin\migrate\destination\EntityContentBase
+ *
+ * Entity revisions can only be migrated after the entity to which the revisions
+ * belong has been migrated. For example, revisions of a given content type can
+ * be migrated only after the nodes of that content type have been migrated.
+ *
+ * In order to avoid revision ID conflicts, make sure that the entity migration
+ * also includes the revision ID. If the entity migration did not include the
+ * revision ID, the entity would get the next available revision ID (1 when
+ * migrating to a clean database). Then, when revisions are migrated after the
+ * entities, the revision IDs would almost certainly collide.
+ *
+ * The examples below contain simple node and node revision migrations. The
+ * examples use the EmbeddedDataSource source plugin for the sake of
+ * simplicity. The important part of both examples is the 'vid' property, which
+ * is the revision ID for nodes.
+ *
+ * Example of 'article' node migration, which must be executed before the
+ * 'article' revisions.
+ * @code
+ * id: custom_article_migration
+ * label: 'Custom article migration'
+ * source:
+ *   plugin: embedded_data
+ *   data_rows:
+ *     -
+ *       nid: 1
+ *       vid: 2
+ *       revision_timestamp: 1514661000
+ *       revision_log: 'Second revision'
+ *       title: 'Current title'
+ *       content: '<p>Current content</p>'
+ *   ids:
+ *     nid:
+ *       type: integer
+ * process:
+ *   nid: nid
+ *   vid: vid
+ *   revision_timestamp: revision_timestamp
+ *   revision_log: revision_log
+ *   title: title
+ *   'body/0/value': content
+ *   'body/0/format':
+ *      plugin: default_value
+ *      default_value: basic_html
+ * destination:
+ *   plugin: entity:node
+ *   default_bundle: article
+ * @endcode
+ *
+ * Example of the corresponding node revision migration, which must be executed
+ * after the above migration.
+ * @code
+ * id: custom_article_revision_migration
+ * label: 'Custom article revision migration'
+ * source:
+ *   plugin: embedded_data
+ *   data_rows:
+ *     -
+ *       nid: 1
+ *       vid: 1
+ *       revision_timestamp: 1514660000
+ *       revision_log: 'First revision'
+ *       title: 'Previous title'
+ *       content: '<p>Previous content</p>'
+ *   ids:
+ *     nid:
+ *       type: integer
+ * process:
+ *   nid:
+ *     plugin: migration_lookup
+ *     migration: custom_article_migration
+ *     source: nid
+ *   vid: vid
+ *   revision_timestamp: revision_timestamp
+ *   revision_log: revision_log
+ *   title: title
+ *   'body/0/value': content
+ *   'body/0/format':
+ *      plugin: default_value
+ *      default_value: basic_html
+ * destination:
+ *   plugin: entity_revision:node
+ *   default_bundle: article
+ * migration_dependencies:
+ *   required:
+ *     - custom_article_migration
+ * @endcode
+ *
  * @MigrateDestination(
  *   id = "entity_revision",
  *   deriver = "Drupal\migrate\Plugin\Derivative\MigrateEntityRevision"
@@ -16,6 +111,16 @@ use Drupal\migrate\Row;
  */
 class EntityRevision extends EntityContentBase {
 
+  /**
+   * {@inheritdoc}
+   */
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, EntityStorageInterface $storage, array $bundles, EntityManagerInterface $entity_manager, FieldTypePluginManagerInterface $field_type_manager) {
+    $plugin_definition += [
+      'label' => new TranslatableMarkup('@entity_type revisions', ['@entity_type' => $storage->getEntityType()->getSingularLabel()]),
+    ];
+    parent::__construct($configuration, $plugin_id, $plugin_definition, $migration, $storage, $bundles, $entity_manager, $field_type_manager);
+  }
+
   /**
    * {@inheritdoc}
    */
@@ -78,4 +183,19 @@ class EntityRevision extends EntityContentBase {
     throw new MigrateException('This entity type does not support revisions.');
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function getHighestId() {
+    $values = $this->storage->getQuery()
+      ->accessCheck(FALSE)
+      ->allRevisions()
+      ->sort($this->getKey('revision'), 'DESC')
+      ->range(0, 1)
+      ->execute();
+    // The array keys are the revision IDs.
+    // The array contains only one entry, so we can use key().
+    return (int) key($values);
+  }
+
 }

core/modules/migrate/src/Plugin/migrate/id_map/NullIdMap.php

@@ -0,0 +1,223 @@
+<?php
+
+namespace Drupal\migrate\Plugin\migrate\id_map;
+
+use Drupal\Core\Plugin\PluginBase;
+use Drupal\migrate\MigrateMessageInterface;
+use Drupal\migrate\Plugin\MigrateIdMapInterface;
+use Drupal\migrate\Plugin\MigrationInterface;
+use Drupal\migrate\Row;
+
+/**
+ * Defines the null ID map implementation.
+ *
+ * This serves as a dummy in order to not store anything.
+ *
+ * @PluginID("null")
+ */
+class NullIdMap extends PluginBase implements MigrateIdMapInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setMessage(MigrateMessageInterface $message) {
+    // Do nothing.
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getRowBySource(array $source_id_values) {
+    return [];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getRowByDestination(array $destination_id_values) {
+    return [];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getRowsNeedingUpdate($count) {
+    return 0;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function lookupSourceID(array $destination_id_values) {
+    return [];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function lookupDestinationId(array $source_id_values) {
+    return [];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function lookupDestinationIds(array $source_id_values) {
+    return [];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function saveIdMapping(Row $row, array $destination_id_values, $source_row_status = MigrateIdMapInterface::STATUS_IMPORTED, $rollback_action = MigrateIdMapInterface::ROLLBACK_DELETE) {
+    // Do nothing.
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function saveMessage(array $source_id_values, $message, $level = MigrationInterface::MESSAGE_ERROR) {
+    // Do nothing.
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getMessageIterator(array $source_id_values = [], $level = NULL) {
+    return new \ArrayIterator([]);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function prepareUpdate() {
+    // Do nothing.
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function processedCount() {
+    return 0;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function importedCount() {
+    return 0;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function updateCount() {
+    return 0;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function errorCount() {
+    return 0;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function messageCount() {
+    return 0;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function delete(array $source_id_values, $messages_only = FALSE) {
+    // Do nothing.
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function deleteDestination(array $destination_id_values) {
+    // Do nothing.
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setUpdate(array $source_id_values) {
+    // Do nothing.
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function clearMessages() {
+    // Do nothing.
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function destroy() {
+    // Do nothing.
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function currentDestination() {
+    return NULL;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function currentSource() {
+    return NULL;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getQualifiedMapTableName() {
+    return '';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function rewind() {
+    return NULL;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function current() {
+    return NULL;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function key() {
+    return '';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function next() {
+    return NULL;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function valid() {
+    return FALSE;
+  }
+
+}

core/modules/migrate/src/Plugin/migrate/id_map/Sql.php

@@ -7,6 +7,7 @@ use Drupal\Core\Field\BaseFieldDefinition;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Drupal\Core\Plugin\PluginBase;
 use Drupal\migrate\MigrateMessage;
+use Drupal\migrate\Audit\HighestIdInterface;
 use Drupal\migrate\Plugin\MigrationInterface;
 use Drupal\migrate\Event\MigrateIdMapMessageEvent;
 use Drupal\migrate\MigrateException;
@@ -27,7 +28,7 @@ use Symfony\Component\EventDispatcher\EventDispatcherInterface;
  *
  * @PluginID("sql")
  */
-class Sql extends PluginBase implements MigrateIdMapInterface, ContainerFactoryPluginInterface {
+class Sql extends PluginBase implements MigrateIdMapInterface, ContainerFactoryPluginInterface, HighestIdInterface {
 
   /**
    * Column name of hashed source id values.
@@ -152,6 +153,8 @@ class Sql extends PluginBase implements MigrateIdMapInterface, ContainerFactoryP
    *   The configuration for the plugin.
    * @param \Drupal\migrate\Plugin\MigrationInterface $migration
    *   The migration to do.
+   * @param \Symfony\Component\EventDispatcher\EventDispatcherInterface $event_dispatcher
+   *   The event dispatcher.
    */
   public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, EventDispatcherInterface $event_dispatcher) {
     parent::__construct($configuration, $plugin_id, $plugin_definition);
@@ -693,7 +696,7 @@ class Sql extends PluginBase implements MigrateIdMapInterface, ContainerFactoryP
    * {@inheritdoc}
    */
   public function processedCount() {
-    return $this->getDatabase()->select($this->mapTableName())
+    return (int) $this->getDatabase()->select($this->mapTableName())
       ->countQuery()
       ->execute()
       ->fetchField();
@@ -703,7 +706,7 @@ class Sql extends PluginBase implements MigrateIdMapInterface, ContainerFactoryP
    * {@inheritdoc}
    */
   public function importedCount() {
-    return $this->getDatabase()->select($this->mapTableName())
+    return (int) $this->getDatabase()->select($this->mapTableName())
       ->condition('source_row_status', [MigrateIdMapInterface::STATUS_IMPORTED, MigrateIdMapInterface::STATUS_NEEDS_UPDATE], 'IN')
       ->countQuery()
       ->execute()
@@ -747,7 +750,7 @@ class Sql extends PluginBase implements MigrateIdMapInterface, ContainerFactoryP
     if (isset($status)) {
       $query->condition('source_row_status', $status);
     }
-    return $query->countQuery()->execute()->fetchField();
+    return (int) $query->countQuery()->execute()->fetchField();
   }
 
   /**
@@ -925,4 +928,69 @@ class Sql extends PluginBase implements MigrateIdMapInterface, ContainerFactoryP
     return $this->currentRow !== FALSE;
   }
 
+  /**
+   * Returns the migration plugin manager.
+   *
+   * @todo Inject as a dependency in https://www.drupal.org/node/2919158.
+   *
+   * @return \Drupal\migrate\Plugin\MigrationPluginManagerInterface
+   *   The migration plugin manager.
+   */
+  protected function getMigrationPluginManager() {
+    return \Drupal::service('plugin.manager.migration');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getHighestId() {
+    array_filter(
+      $this->migration->getDestinationPlugin()->getIds(),
+      function (array $id) {
+        if ($id['type'] !== 'integer') {
+          throw new \LogicException('Cannot determine the highest migrated ID without an integer ID column');
+        }
+      }
+    );
+
+    // List of mapping tables to look in for the highest ID.
+    $map_tables = [
+      $this->migration->id() => $this->mapTableName(),
+    ];
+
+    // If there's a bundle, it means we have a derived migration and we need to
+    // find all the mapping tables from the related derived migrations.
+    if ($base_id = substr($this->migration->id(), 0, strpos($this->migration->id(), static::DERIVATIVE_SEPARATOR))) {
+      $migration_manager = $this->getMigrationPluginManager();
+      $migrations = $migration_manager->getDefinitions();
+      foreach ($migrations as $migration_id => $migration) {
+        if ($migration['id'] === $base_id) {
+          // Get this derived migration's mapping table and add it to the list
+          // of mapping tables to look in for the highest ID.
+          $stub = $migration_manager->createInstance($migration_id);
+          $map_tables[$migration_id] = $stub->getIdMap()->mapTableName();
+        }
+      }
+    }
+
+    // Get the highest id from the list of map tables.
+    $ids = [0];
+    foreach ($map_tables as $map_table) {
+      if (!$this->getDatabase()->schema()->tableExists($map_table)) {
+        break;
+      }
+
+      $query = $this->getDatabase()->select($map_table, 'map')
+        ->fields('map', $this->destinationIdFields())
+        ->range(0, 1);
+      foreach (array_values($this->destinationIdFields()) as $order_field) {
+        $query->orderBy($order_field, 'DESC');
+      }
+      $ids[] = $query->execute()->fetchField();
+    }
+
+    // Return the highest of all the mapped IDs.
+    return (int) max($ids);
+  }
+
 }

core/modules/migrate/src/Plugin/migrate/process/FormatDate.php

@@ -15,13 +15,32 @@ use Drupal\migrate\Row;
  * - from_format: The source format string as accepted by
  *   @link http://php.net/manual/datetime.createfromformat.php \DateTime::createFromFormat. @endlink
  * - to_format: The destination format.
- * - timezone: String identifying the required time zone, see
+ * - timezone: (deprecated) String identifying the required time zone, see
+ *   DateTimePlus::__construct(). The timezone configuration key is deprecated
+ *   in Drupal 8.4.x and will be removed before Drupal 9.0.0, use from_timezone
+ *   and to_timezone instead.
+ * - from_timezone: String identifying the required source time zone, see
+ *   DateTimePlus::__construct().
+ * - to_timezone: String identifying the required destination time zone, see
  *   DateTimePlus::__construct().
  * - settings: keyed array of settings, see DateTimePlus::__construct().
  *
+ * Configuration keys from_timezone and to_timezone are both optional. Possible
+ * input variants:
+ * - Both from_timezone and to_timezone are empty. Date will not be converted
+ *   and be treated as date in default timezone.
+ * - Only from_timezone is set. Date will be converted from timezone specified
+ *   in from_timezone key to the default timezone.
+ * - Only to_timezone is set. Date will be converted from the default timezone
+ *   to the timezone specified in to_timezone key.
+ * - Both from_timezone and to_timezone are set. Date will be converted from
+ *   timezone specified in from_timezone key to the timezone specified in
+ *   to_timezone key.
+ *
  * Examples:
  *
- * Example usage for date only fields (DATETIME_DATE_STORAGE_FORMAT):
+ * Example usage for date only fields
+ * (DateTimeItemInterface::DATE_STORAGE_FORMAT):
  * @code
  * process:
  *   field_date:
@@ -34,7 +53,8 @@ use Drupal\migrate\Row;
  * If the source value was '01/05/1955' the transformed value would be
  * 1955-01-05.
  *
- * Example usage for datetime fields (DATETIME_DATETIME_STORAGE_FORMAT):
+ * Example usage for datetime fields
+ * (DateTimeItemInterface::DATETIME_STORAGE_FORMAT):
  * @code
  * process:
  *   field_time:
@@ -54,7 +74,8 @@ use Drupal\migrate\Row;
  *     plugin: format_date
  *     from_format: 'Y-m-d\TH:i:sO'
  *     to_format: 'Y-m-d\TH:i:s'
- *     timezone: 'America/Managua'
+ *     from_timezone: 'America/Managua'
+ *     to_timezone: 'UTC'
  *     settings:
  *       validate_format: false
  *     source: event_time
@@ -65,6 +86,7 @@ use Drupal\migrate\Row;
  *
  * @see \DateTime::createFromFormat()
  * @see \Drupal\Component\Datetime\DateTimePlus::__construct()
+ * @see \Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface
  * @see \Drupal\migrate\Plugin\MigrateProcessInterface
  *
  * @MigrateProcessPlugin(
@@ -91,14 +113,24 @@ class FormatDate extends ProcessPluginBase {
 
     $fromFormat = $this->configuration['from_format'];
     $toFormat = $this->configuration['to_format'];
-    $timezone = isset($this->configuration['timezone']) ? $this->configuration['timezone'] : NULL;
+    if (isset($this->configuration['timezone'])) {
+      @trigger_error('Configuration key "timezone" is deprecated in 8.4.x and will be removed before Drupal 9.0.0, use "from_timezone" and "to_timezone" instead. See https://www.drupal.org/node/2885746', E_USER_DEPRECATED);
+      $from_timezone = $this->configuration['timezone'];
+      $to_timezone = isset($this->configuration['to_timezone']) ? $this->configuration['to_timezone'] : NULL;
+    }
+    else {
+      $system_timezone = date_default_timezone_get();
+      $default_timezone = !empty($system_timezone) ? $system_timezone : 'UTC';
+      $from_timezone = isset($this->configuration['from_timezone']) ? $this->configuration['from_timezone'] : $default_timezone;
+      $to_timezone = isset($this->configuration['to_timezone']) ? $this->configuration['to_timezone'] : $default_timezone;
+    }
     $settings = isset($this->configuration['settings']) ? $this->configuration['settings'] : [];
 
     // Attempts to transform the supplied date using the defined input format.
     // DateTimePlus::createFromFormat can throw exceptions, so we need to
     // explicitly check for problems.
     try {
-      $transformed = DateTimePlus::createFromFormat($fromFormat, $value, $timezone, $settings)->format($toFormat);
+      $transformed = DateTimePlus::createFromFormat($fromFormat, $value, $from_timezone, $settings)->format($toFormat, ['timezone' => $to_timezone]);
     }
     catch (\InvalidArgumentException $e) {
       throw new MigrateException(sprintf('Format date plugin could not transform "%s" using the format "%s". Error: %s', $value, $fromFormat, $e->getMessage()), $e->getCode(), $e);

core/modules/migrate/src/Plugin/migrate/process/Get.php

@@ -33,7 +33,7 @@ use Drupal\migrate\Row;
  *   bar: foo
  * @endcode
  *
- * get also supports a list of source properties.
+ * Get also supports a list of source properties.
  *
  * Example:
  *
@@ -53,7 +53,7 @@ use Drupal\migrate\Row;
  * value will be used. This makes it impossible to reach a source property with
  * an empty string as its name.
  *
- * get also supports copying destination values. These are indicated by a
+ * Get also supports copying destination values. These are indicated by a
  * starting @ sign. Values using @ must be wrapped in quotes.
  *
  * @code
@@ -69,20 +69,18 @@ use Drupal\migrate\Row;
  * This will simply copy the destination value of foo to the destination
  * property bar. foo configuration is included for illustration purposes.
  *
- * Because of this, if your source or destination property actually starts with
- * a @ you need to double those starting characters up. This means that if a
- * destination property happens to start with a @ and you want to refer it,
- * you'll need to start with three @ characters -- one to indicate the
- * destination and two for escaping the real @.
+ * Because of this, if the source or destination property actually starts with a
+ * @, that character must be escaped with @@.
+ * The referenced property becomes, for example, @@@foo.
  *
  * @code
  * process:
- * @foo:
- *   plugin: machine_name
- *   source: baz
- * bar:
- *   plugin: get
- *   source: '@@@foo'
+ *   '@foo':
+ *     plugin: machine_name
+ *     source: baz
+ *   bar:
+ *     plugin: get
+ *     source: '@@@foo'
  * @endcode
  *
  * This should occur extremely rarely.

core/modules/migrate/src/Plugin/migrate/process/Iterator.php

@@ -2,8 +2,7 @@
 
 namespace Drupal\migrate\Plugin\migrate\process;
 
-@trigger_error('The ' . __NAMESPACE__ . '\Iterator is deprecated in
-Drupal 8.4.x and will be removed before Drupal 9.0.0. Instead, use ' . __NAMESPACE__ . '\SubProcess', E_USER_DEPRECATED);
+@trigger_error('The ' . __NAMESPACE__ . '\Iterator is deprecated in Drupal 8.4.x and will be removed before Drupal 9.0.0. Instead, use ' . __NAMESPACE__ . '\SubProcess', E_USER_DEPRECATED);
 
 /**
  * Iterates and processes an associative array.

core/modules/migrate/src/Plugin/migrate/process/Migration.php

@@ -2,8 +2,7 @@
 
 namespace Drupal\migrate\Plugin\migrate\process;
 
-@trigger_error('The ' . __NAMESPACE__ . '\Migration is deprecated in
-Drupal 8.4.0 and will be removed before Drupal 9.0.0. Instead, use ' . __NAMESPACE__ . '\MigrationLookup', E_USER_DEPRECATED);
+@trigger_error('The ' . __NAMESPACE__ . '\Migration is deprecated in Drupal 8.4.0 and will be removed before Drupal 9.0.0. Instead, use ' . __NAMESPACE__ . '\MigrationLookup', E_USER_DEPRECATED);
 
 /**
  * Calculates the value of a property based on a previous migration.

core/modules/migrate/src/Plugin/migrate/process/MigrationLookup.php

@@ -34,10 +34,12 @@ use Symfony\Component\DependencyInjection\ContainerInterface;
  *
  * Examples:
  *
- * Consider a node migration, where you want to maintain authorship. If you have
- * migrated the user accounts in a migration named "users", you would specify
- * the following:
- *
+ * Consider a node migration, where you want to maintain authorship. Let's
+ * assume that users are previously migrated in a migration named 'users'. The
+ * 'users' migration saved the mapping between the source and destination IDs in
+ * a map table. The node migration example below maps the node 'uid' property so
+ * that we first take the source 'author' value and then do a lookup for the
+ * corresponding Drupal user ID from the map table.
  * @code
  * process:
  *   uid:
@@ -46,15 +48,10 @@ use Symfony\Component\DependencyInjection\ContainerInterface;
  *     source: author
  * @endcode
  *
- * This takes the value of the author property in the source data, and looks it
- * up in the map table associated with the users migration, returning the
- * resulting user ID and assigning it to the destination uid property.
- *
  * The value of 'migration' can be a list of migration IDs. When using multiple
  * migrations it is possible each use different source identifiers. In this
  * case one can use source_ids which is an array keyed by the migration IDs
- * and the value is a list of source properties.
- *
+ * and the value is a list of source properties. See example below.
  * @code
  * process:
  *   uid:
@@ -73,8 +70,8 @@ use Symfony\Component\DependencyInjection\ContainerInterface;
  * map it will create a stub entity for the relationship to use. This stub is
  * generated by the migration provided. In the case of multiple migrations the
  * first value of the migration list will be used, but you can select the
- * migration you wish to use by using the stub_id configuration key:
- *
+ * migration you wish to use by using the stub_id configuration key. The example
+ * below uses 'members' migration to create stub entities.
  * @code
  * process:
  *   uid:
@@ -85,12 +82,8 @@ use Symfony\Component\DependencyInjection\ContainerInterface;
  *     stub_id: members
  * @endcode
  *
- * In the above example, the value of stub_id selects the members migration to
- * create any stub entities.
- *
  * To prevent the creation of a stub entity when no relationship is found in the
- * migration map, use no_stub:
- *
+ * migration map, 'no_stub' configuration can be used as shown below.
  * @code
  * process:
  *   uid:
@@ -161,10 +154,6 @@ class MigrationLookup extends ProcessPluginBase implements ContainerFactoryPlugi
     if (!is_array($migration_ids)) {
       $migration_ids = [$migration_ids];
     }
-    if (!is_array($value)) {
-      $value = [$value];
-    }
-    $this->skipOnEmpty($value);
     $self = FALSE;
     /** @var \Drupal\migrate\Plugin\MigrationInterface[] $migrations */
     $destination_ids = NULL;
@@ -176,13 +165,15 @@ class MigrationLookup extends ProcessPluginBase implements ContainerFactoryPlugi
       }
       if (isset($this->configuration['source_ids'][$migration_id])) {
         $configuration = ['source' => $this->configuration['source_ids'][$migration_id]];
-        $source_id_values[$migration_id] = $this->processPluginManager
+        $value = $this->processPluginManager
           ->createInstance('get', $configuration, $this->migration)
           ->transform(NULL, $migrate_executable, $row, $destination_property);
       }
-      else {
-        $source_id_values[$migration_id] = $value;
+      if (!is_array($value)) {
+        $value = [$value];
       }
+      $this->skipOnEmpty($value);
+      $source_id_values[$migration_id] = $value;
       // Break out of the loop as soon as a destination ID is found.
       if ($destination_ids = $migration->getIdMap()->lookupDestinationId($source_id_values[$migration_id])) {
         break;

core/modules/migrate/src/Plugin/migrate/process/SkipOnEmpty.php

@@ -22,8 +22,8 @@ use Drupal\migrate\MigrateSkipRowException;
  *   - process: Prevents further processing of the input property when the value
  *     is empty.
  * - message: (optional) A message to be logged in the {migrate_message_*} table
- *   for this row. Messages are only logged for the 'row' skip level. If not
- *   set, nothing is logged in the message table.
+ *   for this row. Messages are only logged for the 'row' method. If not set,
+ *   nothing is logged in the message table.
  *
  * Examples:
  *
@@ -33,11 +33,10 @@ use Drupal\migrate\MigrateSkipRowException;
  *     plugin: skip_on_empty
  *     method: row
  *     source: field_name
- *     message: 'Field field_name is missed'
+ *     message: 'Field field_name is missing'
  * @endcode
- *
- * If field_name is empty, skips the entire row and the message 'Field
- * field_name is missed' is logged in the message table.
+ * If 'field_name' is empty, the entire row is skipped and the message 'Field
+ * field_name is missing' is logged in the message table.
  *
  * @code
  * process:
@@ -47,12 +46,13 @@ use Drupal\migrate\MigrateSkipRowException;
  *       method: process
  *       source: parent
  *     -
- *       plugin: migration
+ *       plugin: migration_lookup
  *       migration: d6_taxonomy_term
  * @endcode
- *
- * If parent is empty, any further processing of the property is skipped - thus,
- * the next plugin (migration) will not be run.
+ * If 'parent' is empty, any further processing of the property is skipped and
+ * the next process plugin (migration_lookup) will not be run. Combining
+ * skip_on_empty and migration_lookup is a typical process pipeline combination
+ * for hierarchical entities where the root entity does not have a parent.
  *
  * @see \Drupal\migrate\Plugin\MigrateProcessInterface
  *

core/modules/migrate/src/Plugin/migrate/process/StaticMap.php

@@ -17,10 +17,10 @@ use Drupal\migrate\MigrateSkipRowException;
  *
  * Available configuration keys:
  * - source: The input value - either a scalar or an array.
- * - map: An array (of 1 or more dimensions) that identifies the mapping between
+ * - map: An array (of 1 or more dimensions) that defines the mapping between
  *   source values and destination values.
  * - bypass: (optional) Whether the plugin should proceed when the source is not
- *   found in the map array. Defaults to FALSE.
+ *   found in the map array, defaults to FALSE.
  *   - TRUE: Return the unmodified input value, or another default value, if one
  *     is specified.
  *   - FALSE: Throw a MigrateSkipRowException.
@@ -29,6 +29,8 @@ use Drupal\migrate\MigrateSkipRowException;
  *
  * Examples:
  *
+ * If the value of the source property 'foo' is 'from' then the value of the
+ * destination property bar will be 'to'. Similarly 'this' becomes 'that'.
  * @code
  * process:
  *   bar:
@@ -39,68 +41,75 @@ use Drupal\migrate\MigrateSkipRowException;
  *       this: that
  * @endcode
  *
- * If the value of the source property foo was "from" then the value of the
- * destination property bar will be "to". Similarly "this" becomes "that".
- * static_map can do a lot more than this: it supports a list of source
- * properties. This is super useful in module-delta to machine name conversions.
- *
+ * The static_map process plugin supports a list of source properties. This is
+ * useful in module-delta to machine name conversions. In the example below,
+ * value 'filter_url' is returned if the source property 'module' is 'filter'
+ * and the source property 'delta' is '2'.
  * @code
  * process:
  *   id:
  *     plugin: static_map
- *       source:
- *         - module
- *         - delta
- *        map:
- *          filter:
- *            0: filter_html_escape
- *            1: filter_autop
- *            2: filter_url
- *            3: filter_htmlcorrector
- *            4: filter_html_escape
- *          php:
- *            0: php_code
+ *     source:
+ *       - module
+ *       - delta
+ *     map:
+ *       filter:
+ *         0: filter_html_escape
+ *         1: filter_autop
+ *         2: filter_url
+ *         3: filter_htmlcorrector
+ *         4: filter_html_escape
+ *       php:
+ *         0: php_code
  * @endcode
  *
- * If the value of the source properties module and delta are "filter" and "2"
- * respectively, then the returned value will be "filter_url". By default, if a
- * value is not found in the map, an exception is thrown.
- *
- * When static_map is used to just rename a few things and leave the others, a
- * "bypass: true" option can be added. In this case, the source value is used
- * unchanged, e.g.:
- *
+ * When static_map is used to just rename a few values and leave the others
+ * unchanged, a 'bypass: true' option can be used. See the example below. If the
+ * value of the source property 'foo' is 'from', 'to' will be returned. If the
+ * value of the source property 'foo' is 'another' (a value that is not in the
+ * map), 'another' will be returned unchanged.
  * @code
  * process:
  *   bar:
  *     plugin: static_map
  *     source: foo
- *       map:
- *         from: to
- *         this: that
- *       bypass: TRUE
+ *     map:
+ *       from: to
+ *       this: that
+ *     bypass: TRUE
  * @endcode
  *
- * If the value of the source property "foo" is "from" then the returned value
- * will be "to", but if the value of "foo" is "another" (a value that is not in
- * the map) then the source value is used unchanged so the returned value will
- * be "from" because "bypass" is set to TRUE.
- *
+ * A default value can be defined for all values that are not included in the
+ * map. See the example below. If the value of the source property 'foo' is
+ * 'yet_another' (a value that is not in the map), 'bar' will be returned.
  * @code
  * process:
  *   bar:
  *     plugin: static_map
  *     source: foo
- *       map:
- *         from: to
- *         this: that
- *       default_value: bar
+ *     map:
+ *       from: to
+ *       this: that
+ *     default_value: bar
  * @endcode
  *
- * If the value of the source property "foo" is "yet_another" (a value that is
- * not in the map) then the default_value is used so the returned value will
- * be "bar".
+ * If your source data has boolean values as strings, you need to use single
+ * quotes in the map. See the example below.
+ * @code
+ * process:
+ *   bar:
+ *     plugin: static_map
+ *     source: foo
+ *     map:
+ *       'TRUE': to
+ * @endcode
  *
+ * Mapping from a string which contains a period is not supported. A custom
+ * process plugin can be written to handle this kind of a transformation.
+ * Another option which may be feasible in certain use cases is to first pass
+ * the value through the machine_name process plugin.
+ *
+ * @see https://www.drupal.org/project/drupal/issues/2827897
  * @see \Drupal\migrate\Plugin\MigrateProcessInterface
  *
  * @MigrateProcessPlugin(

core/modules/migrate/src/Plugin/migrate/process/SubProcess.php

@@ -18,8 +18,10 @@ use Drupal\migrate\Row;
  *   - key: runs the process pipeline for the key to determine a new dynamic
  *     name.
  *
- * Examples:
+ * Example 1:
  *
+ * This example demonstrates how migration_lookup process plugin can be applied
+ * on the following source data.
  * @code
  * source: Array
  * (
@@ -41,10 +43,8 @@ use Drupal\migrate\Row;
  * )
  * ...
  * @endcode
- *
  * The sub_process process plugin will take these arrays one at a time and run
- * its own process over each one:
- *
+ * its own process for each of them:
  * @code
  * process:
  *   upload:
@@ -58,16 +58,17 @@ use Drupal\migrate\Row;
  *       display: list
  *       description: description
  * @endcode
- *
  * In this case, each item in the upload array will be processed by the
  * sub_process process plugin. The target_id will be found by looking up the
- * destination value from a previous migration. The display and description
- * fields will simply be mapped.
+ * destination value from a previous migration using the migration_lookup
+ * process plugin. The display and description fields will be mapped directly.
  *
- * In the next example, normally the array returned from sub_process will have
- * its original keys. If you need to change the key, it is possible for the
- * returned array to be keyed by one of the transformed values in the sub-array.
+ * Example 2.
  *
+ * Drupal 6 filter formats contain a list of filters belonging to that format
+ * identified by a numeric delta. A delta of 1 indicates automatic linebreaks,
+ * delta of 2 indicates the URL filter and so on. This example demonstrates how
+ * static_map process plugin can be applied on the following source data.
  * @code
  * source: Array
  * (
@@ -91,7 +92,52 @@ use Drupal\migrate\Row;
  *    )
  * )
  * ...
+ * @endcode
+ * The sub_process will take these arrays one at a time and run its own process
+ * for each of them:
+ * @code
+ * process:
+ *   filters:
+ *     plugin: sub_process
+ *     source: filters
+ *     process:
+ *       id:
+ *         plugin: static_map
+ *         source:
+ *           - module
+ *           - delta
+ *         map:
+ *           filter:
+ *             0: filter_html_escape
+ *             1: filter_autop
+ *             2: filter_url
+ *             3: filter_htmlcorrector
+ *             4: filter_html_escape
+ *           php:
+ *             0: php_code
+ * @endcode
+ * The example above means that we take each array element ([0], [1], etc.) from
+ * the source filters field and apply the static_map plugin on it. Let's have a
+ * closer look at the first array at index 0:
+ * @code
+ * Array
+ * (
+ *    [module] => filter
+ *    [delta] => 2
+ *    [weight] => 0
+ * )
+ * @endcode
+ * The static_map process plugin results to value 'filter_url' for this input
+ * based on the 'module' and 'delta' map.
  *
+ * Example 3.
+ *
+ * Normally the array returned from sub_process will have its original keys. If
+ * you need to change the key, it is possible for the returned array to be keyed
+ * by one of the transformed values in the sub-array. For the same source data
+ * used in the previous example, the migration below would result to keys
+ * 'filter_2' and 'filter_0'.
+ * @code
  * process:
  *   filters:
  *     plugin: sub_process
@@ -106,9 +152,8 @@ use Drupal\migrate\Row;
  *         delimiter: _
  * @endcode
  *
- * In the above example, the keys of the returned array would be filter_2 and
- * filter_0
- *
+ * @see \Drupal\migrate\Plugin\migrate\process\MigrationLookup
+ * @see \Drupal\migrate\Plugin\migrate\process\StaticMap
  * @see \Drupal\migrate\Plugin\MigrateProcessInterface
  *
  * @MigrateProcessPlugin(

core/modules/migrate/src/Plugin/migrate/process/Substr.php

@@ -12,19 +12,19 @@ use Drupal\Component\Utility\Unicode;
  * Returns a substring of the input value.
  *
  * The substr process plugin returns the portion of the input value specified by
- * the start and length parameters. This is a wrapper around the PHP substr()
- * function.
+ * the start and length parameters. This is a wrapper around
+ * \Drupal\Component\Utility\Unicode::substr().
  *
  * Available configuration keys:
  * - start: (optional) The returned string will start this many characters after
- *   the beginning of the string. Defaults to NULL.
+ *   the beginning of the string, defaults to 0.
  * - length: (optional) The maximum number of characters in the returned
- *   string. Defaults to NULL.
+ *   string, defaults to NULL.
  *
- * If start is NULL and length is an integer, the start position is the
+ * If start is 0 and length is an integer, the start position is the
  * beginning of the string. If start is an integer and length is NULL, the
  * substring starting from the start position until the end of the string will
- * be returned. If both start and length are NULL the entire string is returned.
+ * be returned. If start is 0 and length is NULL the entire string is returned.
  *
  * Example:
  *
@@ -33,19 +33,33 @@ use Drupal\Component\Utility\Unicode;
  *   new_text_field:
  *     plugin: substr
  *     source: some_text_field
- *       start: 6
- *       length: 10
+ *     start: 6
+ *     length: 10
  * @endcode
- *
  * If some_text_field was 'Marie Skłodowska Curie' then
  * $destination['new_text_field'] would be 'Skłodowska'.
  *
  * The PHP equivalent of this is:
- *
  * @code
  * $destination['new_text_field'] = substr($source['some_text_field'], 6, 10);
  * @endcode
  *
+ * The substr plugin requires that the source value is not empty. If empty
+ * values are expected, combine skip_on_empty process plugin to the pipeline:
+ * @code
+ * process:
+ *   new_text_field:
+ *    -
+ *      plugin: skip_on_empty
+ *      method: process
+ *      source: some_text_field
+ *    -
+ *      plugin: substr
+ *      source: some_text_field
+ *      start: 6
+ *      length: 10
+ * @endcode
+ *
  * @see \Drupal\migrate\Plugin\MigrateProcessInterface
  *
  * @MigrateProcessPlugin(

core/modules/migrate/src/Plugin/migrate/source/EmbeddedDataSource.php

@@ -38,7 +38,8 @@ use Drupal\migrate\Plugin\MigrationInterface;
  * @see \Drupal\migrate\Plugin\MigrateSourceInterface
  *
  * @MigrateSource(
- *   id = "embedded_data"
+ *   id = "embedded_data",
+ *   source_module = "migrate"
  * )
  */
 class EmbeddedDataSource extends SourcePluginBase {
@@ -108,7 +109,7 @@ class EmbeddedDataSource extends SourcePluginBase {
   /**
    * {@inheritdoc}
    */
-  public function count() {
+  public function count($refresh = FALSE) {
     return count($this->dataRows);
   }
 

core/modules/migrate/src/Plugin/migrate/source/EmptySource.php

@@ -58,7 +58,7 @@ class EmptySource extends SourcePluginBase {
   /**
    * {@inheritdoc}
    */
-  public function count() {
+  public function count($refresh = FALSE) {
     return 1;
   }
 

core/modules/migrate/src/Plugin/migrate/source/SourcePluginBase.php

@@ -216,8 +216,8 @@ abstract class SourcePluginBase extends PluginBase implements MigrateSourceInter
   /**
    * Initializes the iterator with the source data.
    *
-   * @return array
-   *   An array of the data for this source.
+   * @return \Iterator
+   *   Returns an iteratable object of data for this source.
    */
   abstract protected function initializeIterator();
 

core/modules/migrate/src/Plugin/migrate/source/SqlBase.php

@@ -346,7 +346,9 @@ abstract class SqlBase extends SourcePluginBase implements ContainerFactoryPlugi
     if (($this->batchSize > 0)) {
       $this->query->range($this->batch * $this->batchSize, $this->batchSize);
     }
-    return new \IteratorIterator($this->query->execute());
+    $statement = $this->query->execute();
+    $statement->setFetchMode(\PDO::FETCH_ASSOC);
+    return new \IteratorIterator($statement);
   }
 
   /**
@@ -379,7 +381,7 @@ abstract class SqlBase extends SourcePluginBase implements ContainerFactoryPlugi
    * {@inheritdoc}
    */
   public function count($refresh = FALSE) {
-    return $this->query()->countQuery()->execute()->fetchField();
+    return (int) $this->query()->countQuery()->execute()->fetchField();
   }
 
   /**

core/modules/migrate/src/Row.php

@@ -104,7 +104,7 @@ class Row {
     $this->isStub = $is_stub;
     foreach (array_keys($source_ids) as $id) {
       if (!$this->hasSourceProperty($id)) {
-        throw new \InvalidArgumentException("$id has no value");
+        throw new \InvalidArgumentException("$id is defined as a source ID but has no value.");
       }
     }
   }

core/modules/migrate/tests/modules/migrate_entity_test/migrate_entity_test.info.yml

@@ -5,8 +5,8 @@ package: Testing
 # version: VERSION
 # core: 8.x
 
-# Information added by Drupal.org packaging script on 2018-01-03
-version: '8.4.4'
+# Information added by Drupal.org packaging script on 2018-03-07
+version: '8.5.0'
 core: '8.x'
 project: 'drupal'
-datestamp: 1515021228
+datestamp: 1520457825

core/modules/migrate/tests/modules/migrate_events_test/migrate_events_test.info.yml

@@ -4,8 +4,8 @@ package: Testing
 # version: VERSION
 # core: 8.x
 
-# Information added by Drupal.org packaging script on 2018-01-03
-version: '8.4.4'
+# Information added by Drupal.org packaging script on 2018-03-07
+version: '8.5.0'
 core: '8.x'
 project: 'drupal'
-datestamp: 1515021228
+datestamp: 1520457825

core/modules/migrate/tests/modules/migrate_external_translated_test/migrate_external_translated_test.info.yml

@@ -7,8 +7,8 @@ dependencies:
   - node
   - migrate
 
-# Information added by Drupal.org packaging script on 2018-01-03
-version: '8.4.4'
+# Information added by Drupal.org packaging script on 2018-03-07
+version: '8.5.0'
 core: '8.x'
 project: 'drupal'
-datestamp: 1515021228
+datestamp: 1520457825

core/modules/migrate/tests/modules/migrate_high_water_test/migrate_high_water_test.info.yml

@@ -6,8 +6,8 @@ package: Testing
 dependencies:
   - migrate
 
-# Information added by Drupal.org packaging script on 2018-01-03
-version: '8.4.4'
+# Information added by Drupal.org packaging script on 2018-03-07
+version: '8.5.0'
 core: '8.x'
 project: 'drupal'
-datestamp: 1515021228
+datestamp: 1520457825

core/modules/migrate/tests/modules/migrate_prepare_row_test/migrate_prepare_row_test.info.yml

@@ -5,8 +5,8 @@ package: Testing
 # version: VERSION
 # core: 8.x
 
-# Information added by Drupal.org packaging script on 2018-01-03
-version: '8.4.4'
+# Information added by Drupal.org packaging script on 2018-03-07
+version: '8.5.0'
 core: '8.x'
 project: 'drupal'
-datestamp: 1515021228
+datestamp: 1520457825

core/modules/migrate/tests/modules/migrate_query_batch_test/migrate_query_batch_test.info.yml

@@ -6,8 +6,8 @@ package: Testing
 dependencies:
   - migrate
 
-# Information added by Drupal.org packaging script on 2018-01-03
-version: '8.4.4'
+# Information added by Drupal.org packaging script on 2018-03-07
+version: '8.5.0'
 core: '8.x'
 project: 'drupal'
-datestamp: 1515021228
+datestamp: 1520457825

core/modules/migrate/tests/modules/migration_directory_test/migration_directory_test.info.yml

@@ -0,0 +1,13 @@
+name: 'Migration directory test'
+type: module
+package: Testing
+# version: VERSION
+# core: 8.x
+dependencies:
+  - migrate
+
+# Information added by Drupal.org packaging script on 2018-03-07
+version: '8.5.0'
+core: '8.x'
+project: 'drupal'
+datestamp: 1520457825

core/modules/migrate/tests/modules/migration_directory_test/migration_templates/migration_templates_test.yml

@@ -0,0 +1,8 @@
+id: migration_templates_test
+label: Migration templates test
+source:
+  plugin: embedded_data
+process:
+  id: id
+destination:
+  plugin: null

core/modules/migrate/tests/src/Functional/process/DownloadFunctionalTest.php

@@ -3,7 +3,6 @@
 namespace Drupal\Tests\migrate\Functional\process;
 
 use Drupal\migrate\MigrateExecutable;
-use Drupal\migrate\MigrateMessage;
 use Drupal\migrate\Plugin\MigrateIdMapInterface;
 use Drupal\migrate\Plugin\MigrationInterface;
 use Drupal\Tests\BrowserTestBase;
@@ -51,7 +50,7 @@ class DownloadFunctionalTest extends BrowserTestBase {
 
     $migration = \Drupal::service('plugin.manager.migration')->createStubMigration($definition);
 
-    $executable = new MigrateExecutable($migration, new MigrateMessage());
+    $executable = new MigrateExecutable($migration);
     $result = $executable->import();
 
     // Check that the migration has completed.

core/modules/migrate/tests/src/Kernel/MigrateEntityContentBaseTest.php

@@ -2,10 +2,10 @@
 
 namespace Drupal\Tests\migrate\Kernel;
 
+use Drupal\entity_test\Entity\EntityTestMul;
 use Drupal\KernelTests\KernelTestBase;
 use Drupal\language\Entity\ConfigurableLanguage;
 use Drupal\migrate\MigrateExecutable;
-use Drupal\migrate\MigrateMessage;
 use Drupal\migrate\Plugin\migrate\destination\EntityContentBase;
 use Drupal\migrate\Plugin\MigrateIdMapInterface;
 use Drupal\migrate\Plugin\MigrationInterface;
@@ -45,6 +45,11 @@ class MigrateEntityContentBaseTest extends KernelTestBase {
    */
   protected function setUp() {
     parent::setUp();
+
+    // Enable two required fields with default values: a single-value field and
+    // a multi-value field.
+    \Drupal::state()->set('entity_test.required_default_field', TRUE);
+    \Drupal::state()->set('entity_test.required_multi_default_field', TRUE);
     $this->installEntitySchema('entity_test_mul');
 
     ConfigurableLanguage::createFromLangcode('en')->save();
@@ -191,7 +196,7 @@ class MigrateEntityContentBaseTest extends KernelTestBase {
     ];
 
     $migration = \Drupal::service('plugin.manager.migration')->createStubMigration($definition);
-    $executable = new MigrateExecutable($migration, new MigrateMessage());
+    $executable = new MigrateExecutable($migration);
     $result = $executable->import();
     $this->assertEquals(MigrationInterface::RESULT_COMPLETED, $result);
 
@@ -239,7 +244,7 @@ class MigrateEntityContentBaseTest extends KernelTestBase {
 
     $migration = \Drupal::service('plugin.manager.migration')
       ->createStubMigration($definition);
-    $executable = new MigrateExecutable($migration, new MigrateMessage());
+    $executable = new MigrateExecutable($migration);
     $executable->import();
 
     /** @var \Drupal\migrate_entity_test\Entity\StringIdEntityTest $entity */
@@ -256,7 +261,7 @@ class MigrateEntityContentBaseTest extends KernelTestBase {
 
     $migration = \Drupal::service('plugin.manager.migration')
       ->createStubMigration($definition);
-    $executable = new MigrateExecutable($migration, new MigrateMessage());
+    $executable = new MigrateExecutable($migration);
     $executable->import();
 
     /** @var \Drupal\migrate_entity_test\Entity\StringIdEntityTest $entity */
@@ -266,4 +271,34 @@ class MigrateEntityContentBaseTest extends KernelTestBase {
     $this->assertNull($entity->version->value);
   }
 
+  /**
+   * Tests stub rows.
+   */
+  public function testStubRows() {
+    // Create a destination.
+    $this->createDestination([]);
+
+    // Import a stub row.
+    $row = new Row([], [], TRUE);
+    $row->setDestinationProperty('type', 'test');
+    $ids = $this->destination->import($row);
+    $this->assertCount(1, $ids);
+
+    // Make sure the entity was saved.
+    $entity = EntityTestMul::load(reset($ids));
+    $this->assertInstanceOf(EntityTestMul::class, $entity);
+    // Make sure the default value was applied to the required fields.
+    $single_field_name = 'required_default_field';
+    $single_default_value = $entity->getFieldDefinition($single_field_name)->getDefaultValueLiteral();
+    $this->assertSame($single_default_value, $entity->get($single_field_name)->getValue());
+
+    $multi_field_name = 'required_multi_default_field';
+    $multi_default_value = $entity->getFieldDefinition($multi_field_name)->getDefaultValueLiteral();
+    $count = 3;
+    $this->assertCount($count, $multi_default_value);
+    for ($i = 0; $i < $count; ++$i) {
+      $this->assertSame($multi_default_value[$i], $entity->get($multi_field_name)->get($i)->getValue());
+    }
+  }
+
 }

core/modules/migrate/tests/src/Kernel/MigrateEventsTest.php

@@ -7,7 +7,6 @@ use Drupal\migrate\Event\MigrateMapDeleteEvent;
 use Drupal\migrate\Event\MigrateMapSaveEvent;
 use Drupal\migrate\Event\MigratePostRowSaveEvent;
 use Drupal\migrate\Event\MigratePreRowSaveEvent;
-use Drupal\migrate\MigrateMessage;
 use Drupal\migrate\Event\MigrateEvents;
 use Drupal\migrate\MigrateExecutable;
 use Drupal\KernelTests\KernelTestBase;
@@ -76,7 +75,7 @@ class MigrateEventsTest extends KernelTestBase {
 
     $migration = \Drupal::service('plugin.manager.migration')->createStubMigration($definition);
 
-    $executable = new MigrateExecutable($migration, new MigrateMessage());
+    $executable = new MigrateExecutable($migration);
     // As the import runs, events will be dispatched, recording the received
     // information in state.
     $executable->import();

core/modules/migrate/tests/src/Kernel/MigrateInterruptionTest.php

@@ -3,7 +3,6 @@
 namespace Drupal\Tests\migrate\Kernel;
 
 use Drupal\migrate\Event\MigratePostRowSaveEvent;
-use Drupal\migrate\MigrateMessage;
 use Drupal\migrate\Plugin\MigrationInterface;
 use Drupal\migrate\Event\MigrateEvents;
 use Drupal\migrate\MigrateExecutable;
@@ -56,7 +55,7 @@ class MigrateInterruptionTest extends KernelTestBase {
 
     $migration = \Drupal::service('plugin.manager.migration')->createStubMigration($definition);
 
-    $executable = new MigrateExecutable($migration, new MigrateMessage());
+    $executable = new MigrateExecutable($migration);
     // When the import runs, the first row imported will trigger an
     // interruption.
     $result = $executable->import();

core/modules/migrate/tests/src/Kernel/MigrateSkipRowTest.php

@@ -3,7 +3,6 @@
 namespace Drupal\Tests\migrate\Kernel;
 
 use Drupal\KernelTests\KernelTestBase;
-use Drupal\migrate\MigrateMessage;
 use Drupal\migrate\Plugin\MigrationInterface;
 use Drupal\migrate\MigrateExecutable;
 use Drupal\migrate\Plugin\MigrateIdMapInterface;
@@ -50,7 +49,7 @@ class MigrateSkipRowTest extends KernelTestBase {
 
     $migration = \Drupal::service('plugin.manager.migration')->createStubMigration($definition);
 
-    $executable = new MigrateExecutable($migration, new MigrateMessage());
+    $executable = new MigrateExecutable($migration);
     $result = $executable->import();
     $this->assertEqual($result, MigrationInterface::RESULT_COMPLETED);
 
@@ -85,7 +84,7 @@ class MigrateSkipRowTest extends KernelTestBase {
     ];
     $migration = \Drupal::service('plugin.manager.migration')->createStubMigration($definition);
 
-    $executable = new MigrateExecutable($migration, new MigrateMessage());
+    $executable = new MigrateExecutable($migration);
     $result = $executable->import();
     $this->assertEquals($result, MigrationInterface::RESULT_COMPLETED);
 

core/modules/migrate/tests/src/Kernel/Plugin/MigrationDirectoryTest.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace Drupal\Tests\migrate\Kernel\Plugin;
+
+use Drupal\Tests\migrate_drupal\Kernel\MigrateDrupalTestBase;
+
+/**
+ * Tests that migrations exist in the migration_templates directory.
+ *
+ * @group migrate
+ * @group legacy
+ */
+class MigrationDirectoryTest extends MigrateDrupalTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['migration_directory_test'];
+
+  /**
+   * Tests that migrations in the migration_templates directory are created.
+   *
+   * @expectedDeprecationMessage Use of the /migration_templates directory to store migration configuration files is deprecated in Drupal 8.1.0 and will be removed before Drupal 9.0.0.
+   */
+  public function testMigrationDirectory() {
+    /** @var \Drupal\migrate\Plugin\MigrationPluginManager $plugin_manager */
+    $plugin_manager = $this->container->get('plugin.manager.migration');
+    // Tests that a migration in directory 'migration_templates' is discovered.
+    $this->assertTrue($plugin_manager->hasDefinition('migration_templates_test'));
+  }
+
+}

core/modules/migrate/tests/src/Kernel/Plugin/MigrationProvidersExistTest.php

@@ -2,8 +2,9 @@
 
 namespace Drupal\Tests\migrate\Kernel\Plugin;
 
-use Drupal\Component\Render\FormattableMarkup;
 use Drupal\KernelTests\FileSystemModuleDiscoveryDataProviderTrait;
+use Drupal\migrate\Plugin\Exception\BadPluginDefinitionException;
+use Drupal\migrate_drupal\Plugin\MigrateFieldPluginManager;
 use Drupal\Tests\migrate_drupal\Kernel\MigrateDrupalTestBase;
 
 /**
@@ -16,49 +17,215 @@ class MigrationProvidersExistTest extends MigrateDrupalTestBase {
   use FileSystemModuleDiscoveryDataProviderTrait;
 
   /**
-   * {@inheritdoc}
+   * Tests that a missing source_module property raises an exception.
    */
-  public static $modules = ['migration_provider_test'];
+  public function testSourceProvider() {
+    $this->enableModules(['migration_provider_test']);
+    $this->setExpectedException(BadPluginDefinitionException::class, 'The no_source_module plugin must define the source_module property.');
+    $this->container->get('plugin.manager.migration')->getDefinition('migration_provider_no_annotation');
+  }
 
   /**
-   * Tests that modules exist for all source and destination plugins.
+   * Tests that modules exist for all source plugins.
    */
   public function testProvidersExist() {
+    $this->enableAllModules();
+
+    /** @var \Drupal\migrate\Plugin\MigrationPluginManager $plugin_manager */
+    $plugin_manager = $this->container->get('plugin.manager.migration');
+
+    // Instantiate all migrations.
+    $migrations = array_keys($plugin_manager->getDefinitions());
+    $migrations = $plugin_manager->createInstances($migrations);
+
+    /** @var \Drupal\migrate\Plugin\MigrationInterface $migration */
+    foreach ($migrations as $migration) {
+      $this->assertInternalType('string', $migration->getSourcePlugin()->getSourceModule());
+    }
+  }
+
+  /**
+   * Enable all available modules.
+   */
+  protected function enableAllModules() {
     // Install all available modules.
     $module_handler = $this->container->get('module_handler');
     $modules = $this->coreModuleListDataProvider();
     $modules_enabled = $module_handler->getModuleList();
     $modules_to_enable = array_keys(array_diff_key($modules, $modules_enabled));
     $this->enableModules($modules_to_enable);
+  }
 
-    /** @var \Drupal\migrate\Plugin\MigrationPluginManager $plugin_manager */
-    $plugin_manager = $this->container->get('plugin.manager.migration');
-    // Get all the migrations
-    $migrations = $plugin_manager->createInstances(array_keys($plugin_manager->getDefinitions()));
-    // Ensure the test module was enabled.
-    $this->assertTrue(array_key_exists('migration_provider_test', $migrations));
-    $this->assertTrue(array_key_exists('migration_provider_no_annotation', $migrations));
-    /** @var \Drupal\migrate\Plugin\Migration $migration */
-    foreach ($migrations as $migration) {
-      $source_module = $migration->getSourcePlugin()->getSourceModule();
-      $destination_module = $migration->getDestinationPlugin()->getDestinationModule();
-      $migration_id = $migration->getPluginId();
-      if ($migration_id == 'migration_provider_test') {
-        $this->assertFalse($source_module, new FormattableMarkup('Source module not found for @migration_id.', ['@migration_id' => $migration_id]));
-        $this->assertFalse($destination_module, new FormattableMarkup('Destination module not found for @migration_id.', ['@migration_id' => $migration_id]));
-      }
-      elseif ($migration_id == 'migration_provider_no_annotation') {
-        $this->assertFalse($source_module, new FormattableMarkup('Source module not found for @migration_id.', ['@migration_id' => $migration_id]));
-        $this->assertTrue($destination_module, new FormattableMarkup('Destination module found for @migration_id.', ['@migration_id' => $migration_id]));
-      }
-      else {
-        $this->assertTrue($source_module, new FormattableMarkup('Source module found for @migration_id.', ['@migration_id' => $migration_id]));
-        $this->assertTrue($destination_module, new FormattableMarkup('Destination module found for @migration_id.', ['@migration_id' => $migration_id]));
-      }
-      // Destination module can't be migrate or migrate_drupal or migrate_drupal_ui
-      $invalid_destinations = ['migrate', 'migrate_drupal', 'migrate_drupal_ui'];
-      $this->assertNotContains($destination_module, $invalid_destinations, new FormattableMarkup('Invalid destination for @migration_id.', ['@migration_id' => $migration_id]));
+  /**
+   * Tests that modules exist for all field plugins.
+   */
+  public function testFieldProvidersExist() {
+    $expected_mappings = [
+      'userreference' => [
+        'source_module' => 'userreference',
+        'destination_module' => 'core',
+      ],
+      'nodereference' => [
+        'source_module' => 'nodereference',
+        'destination_module' => 'core',
+      ],
+      'optionwidgets' => [
+        'source_module' => 'optionwidgets',
+        'destination_module' => 'options',
+      ],
+      'list' => [
+        'source_module' => 'list',
+        'destination_module' => 'options',
+      ],
+      'options' => [
+        'source_module' => 'options',
+        'destination_module' => 'options',
+      ],
+      'filefield' => [
+        'source_module' => 'filefield',
+        'destination_module' => 'file',
+      ],
+      'imagefield' => [
+        'source_module' => 'imagefield',
+        'destination_module' => 'image',
+      ],
+      'file' => [
+        'source_module' => 'file',
+        'destination_module' => 'file',
+      ],
+      'image' => [
+        'source_module' => 'image',
+        'destination_module' => 'image',
+      ],
+      'phone' => [
+        'source_module' => 'phone',
+        'destination_module' => 'telephone',
+      ],
+      'link' => [
+        'source_module' => 'link',
+        'destination_module' => 'link',
+      ],
+      'link_field' => [
+        'source_module' => 'link',
+        'destination_module' => 'link',
+      ],
+      'd6_text' => [
+        'source_module' => 'text',
+        'destination_module' => 'text',
+      ],
+      'd7_text' => [
+        'source_module' => 'text',
+        'destination_module' => 'text',
+      ],
+      'taxonomy_term_reference' => [
+        'source_module' => 'taxonomy',
+        'destination_module' => 'core',
+      ],
+      'date' => [
+        'source_module' => 'date',
+        'destination_module' => 'datetime',
+      ],
+      'datetime' => [
+        'source_module' => 'date',
+        'destination_module' => 'datetime',
+      ],
+      'email' => [
+        'source_module' => 'email',
+        'destination_module' => 'core',
+      ],
+      'number_default' => [
+        'source_module' => 'number',
+        'destination_module' => 'core',
+      ],
+      'entityreference' => [
+        'source_module' => 'entityreference',
+        'destination_module' => 'core',
+      ],
+    ];
+    $this->enableAllModules();
+
+    $definitions = $this->container->get('plugin.manager.migrate.field')->getDefinitions();
+    foreach ($definitions as $key => $definition) {
+      $this->assertArrayHasKey($key, $expected_mappings);
+      $this->assertEquals($expected_mappings[$key]['source_module'], $definition['source_module']);
+      $this->assertEquals($expected_mappings[$key]['destination_module'], $definition['destination_module']);
     }
   }
 
+  /**
+   * Test a missing required definition.
+   *
+   * @param array $definitions
+   *   A field plugin definition.
+   * @param string $missing_property
+   *   The name of the property missing from the definition.
+   *
+   * @dataProvider fieldPluginDefinitionsProvider
+   */
+  public function testFieldProviderMissingRequiredProperty(array $definitions, $missing_property) {
+    $discovery = $this->getMockBuilder(MigrateFieldPluginManager::class)
+      ->disableOriginalConstructor()
+      ->setMethods(['getDefinitions'])
+      ->getMock();
+    $discovery->method('getDefinitions')
+      ->willReturn($definitions);
+
+    $plugin_manager = $this->getMockBuilder(MigrateFieldPluginManager::class)
+      ->disableOriginalConstructor()
+      ->setMethods(['getDiscovery'])
+      ->getMock();
+    $plugin_manager->method('getDiscovery')
+      ->willReturn($discovery);
+
+    $this->setExpectedException(BadPluginDefinitionException::class, "The missing_{$missing_property} plugin must define the $missing_property property.");
+    $plugin_manager->getDefinitions();
+  }
+
+  /**
+   * Data provider for field plugin definitions.
+   *
+   * @return array
+   *   Array of plugin definitions.
+   */
+  public function fieldPluginDefinitionsProvider() {
+    return [
+      'missing_core_scenario' => [
+        'definitions' => [
+          'missing_core' => [
+            'source_module' => 'migrate',
+            'destination_module' => 'migrate',
+            'id' => 'missing_core',
+            'class' => 'foo',
+            'provider' => 'foo',
+          ],
+        ],
+        'missing_property' => 'core',
+      ],
+      'missing_source_scenario' => [
+        'definitions' => [
+          'missing_source_module' => [
+            'core' => [6, 7],
+            'destination_module' => 'migrate',
+            'id' => 'missing_source_module',
+            'class' => 'foo',
+            'provider' => 'foo',
+          ],
+        ],
+        'missing_property' => 'source_module',
+      ],
+      'missing_destination_scenario' => [
+        'definitions' => [
+          'missing_destination_module' => [
+            'core' => [6, 7],
+            'source_module' => 'migrate',
+            'id' => 'missing_destination_module',
+            'class' => 'foo',
+            'provider' => 'foo',
+          ],
+        ],
+        'missing_property' => 'destination_module',
+      ],
+    ];
+  }
+
 }

core/modules/migrate/tests/src/Kernel/SqlBaseTest.php

@@ -9,6 +9,7 @@ namespace Drupal\Tests\migrate\Kernel;
 
 use Drupal\Core\Database\Query\ConditionInterface;
 use Drupal\Core\Database\Query\SelectInterface;
+use Drupal\Core\Database\StatementInterface;
 use Drupal\migrate\Exception\RequirementsException;
 use Drupal\Core\Database\Database;
 use Drupal\migrate\Plugin\migrate\source\SqlBase;
@@ -46,8 +47,8 @@ class SqlBaseTest extends MigrateTestBase {
 
     // Verify that falling back to the default 'migrate' connection (defined in
     // the base class) works.
-    $this->assertSame($sql_base->getDatabase()->getTarget(), 'default');
-    $this->assertSame($sql_base->getDatabase()->getKey(), 'migrate');
+    $this->assertSame('default', $sql_base->getDatabase()->getTarget());
+    $this->assertSame('migrate', $sql_base->getDatabase()->getKey());
 
     // Verify the fallback state key overrides the 'migrate' connection.
     $target = 'test_fallback_target';
@@ -149,10 +150,10 @@ class SqlBaseTest extends MigrateTestBase {
       $source->getHighWaterStorage()->set($this->migration->id(), $high_water);
     }
 
-    $query_result = new \ArrayIterator($query_result);
-
-    $query = $this->getMock(SelectInterface::class);
-    $query->method('execute')->willReturn($query_result);
+    $statement = $this->createMock(StatementInterface::class);
+    $statement->expects($this->atLeastOnce())->method('setFetchMode')->with(\PDO::FETCH_ASSOC);
+    $query = $this->createMock(SelectInterface::class);
+    $query->method('execute')->willReturn($statement);
     $query->expects($this->atLeastOnce())->method('orderBy')->with('order', 'ASC');
 
     $condition_group = $this->getMock(ConditionInterface::class);

core/modules/migrate/tests/src/Kernel/process/DownloadTest.php

@@ -9,7 +9,6 @@ use Drupal\migrate\Plugin\migrate\process\Download;
 use Drupal\migrate\MigrateExecutableInterface;
 use Drupal\migrate\Row;
 use GuzzleHttp\Client;
-use GuzzleHttp\Psr7\Response;
 
 /**
  * Tests the download process plugin.
@@ -100,14 +99,8 @@ class DownloadTest extends FileTestBase {
    *   The local URI of the downloaded file.
    */
   protected function doTransform($destination_uri, $configuration = []) {
-    // The HTTP client will return a file with contents 'It worked!'
-    $body = fopen('data://text/plain;base64,SXQgd29ya2VkIQ==', 'r');
-
     // Prepare a mock HTTP client.
     $this->container->set('http_client', $this->getMock(Client::class));
-    $this->container->get('http_client')
-      ->method('get')
-      ->willReturn(new Response(200, [], $body));
 
     // Instantiate the plugin statically so it can pull dependencies out of
     // the container.

core/modules/migrate/tests/src/Kernel/process/ExtractTest.php

@@ -4,7 +4,6 @@ namespace Drupal\Tests\migrate\Kernel\process;
 
 use Drupal\KernelTests\KernelTestBase;
 use Drupal\migrate\MigrateExecutable;
-use Drupal\migrate\MigrateMessage;
 use Drupal\migrate\Plugin\MigrationInterface;
 
 /**
@@ -66,7 +65,7 @@ class ExtractTest extends KernelTestBase {
 
     $migration = \Drupal::service('plugin.manager.migration')->createStubMigration($definition);
 
-    $executable = new MigrateExecutable($migration, new MigrateMessage());
+    $executable = new MigrateExecutable($migration);
     $result = $executable->import();
 
     // Migration needs to succeed before further assertions are made.

core/modules/migrate/tests/src/Kernel/process/HandleMultiplesTest.php

@@ -4,7 +4,6 @@ namespace Drupal\Tests\migrate\Kernel\process;
 
 use Drupal\KernelTests\KernelTestBase;
 use Drupal\migrate\MigrateExecutable;
-use Drupal\migrate\MigrateMessage;
 use Drupal\migrate\Plugin\MigrationInterface;
 
 /**
@@ -94,7 +93,7 @@ class HandleMultiplesTest extends KernelTestBase {
 
     $migration = \Drupal::service('plugin.manager.migration')->createStubMigration($definition);
 
-    $executable = new MigrateExecutable($migration, new MigrateMessage());
+    $executable = new MigrateExecutable($migration);
     $result = $executable->import();
 
     // Migration needs to succeed before further assertions are made.

core/modules/migrate/tests/src/Unit/Exception/RequirementsExceptionTest.php

@@ -7,7 +7,7 @@ use Drupal\Tests\UnitTestCase;
 
 /**
  * @coversDefaultClass \Drupal\migrate\Exception\RequirementsException
- * @group migration
+ * @group migrate
  */
 class RequirementsExceptionTest extends UnitTestCase {
 

core/modules/migrate/tests/src/Unit/MigrateSqlIdMapTest.php

@@ -211,10 +211,10 @@ class MigrateSqlIdMapTest extends MigrateTestCase {
     }
 
     // Truncate and check that 4 messages were deleted.
-    $this->assertEquals($id_map->messageCount(), 4);
+    $this->assertSame($id_map->messageCount(), 4);
     $id_map->clearMessages();
     $count = $id_map->messageCount();
-    $this->assertEquals($count, 0);
+    $this->assertSame($count, 0);
   }
 
   /**
@@ -284,7 +284,7 @@ class MigrateSqlIdMapTest extends MigrateTestCase {
     // Test count message multiple times starting from 0.
     foreach ($expected_results as $key => $expected_result) {
       $count = $id_map->messageCount();
-      $this->assertEquals($expected_result, $count);
+      $this->assertSame($expected_result, $count);
       $id_map->saveMessage(['source_id_property' => $key], $message);
     }
   }
@@ -684,21 +684,21 @@ class MigrateSqlIdMapTest extends MigrateTestCase {
     $row = new Row($source, ['source_id_property' => []]);
     $destination = ['destination_id_property' => 'destination_value_failed'];
     $id_map->saveIdMapping($row, $destination, MigrateIdMapInterface::STATUS_FAILED);
-    $this->assertSame(0, (int) $id_map->importedCount());
+    $this->assertSame(0, $id_map->importedCount());
 
     // Add an imported row and assert single count.
     $source = ['source_id_property' => 'source_value_imported'];
     $row = new Row($source, ['source_id_property' => []]);
     $destination = ['destination_id_property' => 'destination_value_imported'];
     $id_map->saveIdMapping($row, $destination, MigrateIdMapInterface::STATUS_IMPORTED);
-    $this->assertSame(1, (int) $id_map->importedCount());
+    $this->assertSame(1, $id_map->importedCount());
 
     // Add a row needing update and assert multiple imported rows.
     $source = ['source_id_property' => 'source_value_update'];
     $row = new Row($source, ['source_id_property' => []]);
     $destination = ['destination_id_property' => 'destination_value_update'];
     $id_map->saveIdMapping($row, $destination, MigrateIdMapInterface::STATUS_NEEDS_UPDATE);
-    $this->assertSame(2, (int) $id_map->importedCount());
+    $this->assertSame(2, $id_map->importedCount());
   }
 
   /**
@@ -712,7 +712,7 @@ class MigrateSqlIdMapTest extends MigrateTestCase {
   public function testProcessedCount() {
     $id_map = $this->getIdMap();
     // Assert zero rows have been processed before adding rows.
-    $this->assertSame(0, (int) $id_map->processedCount());
+    $this->assertSame(0, $id_map->processedCount());
     $row_statuses = [
       MigrateIdMapInterface::STATUS_IMPORTED,
       MigrateIdMapInterface::STATUS_NEEDS_UPDATE,
@@ -727,11 +727,11 @@ class MigrateSqlIdMapTest extends MigrateTestCase {
       $id_map->saveIdMapping($row, $destination, $status);
       if ($status == MigrateIdMapInterface::STATUS_IMPORTED) {
         // Assert a single row has been processed.
-        $this->assertSame(1, (int) $id_map->processedCount());
+        $this->assertSame(1, $id_map->processedCount());
       }
     }
     // Assert multiple rows have been processed.
-    $this->assertSame(count($row_statuses), (int) $id_map->processedCount());
+    $this->assertSame(count($row_statuses), $id_map->processedCount());
   }
 
   /**
@@ -779,7 +779,7 @@ class MigrateSqlIdMapTest extends MigrateTestCase {
       $this->saveMap($row);
     }
     $id_map = $this->getIdMap();
-    $this->assertSame($num_update_rows, (int) $id_map->updateCount());
+    $this->assertSame($num_update_rows, $id_map->updateCount());
   }
 
   /**
@@ -827,7 +827,7 @@ class MigrateSqlIdMapTest extends MigrateTestCase {
       $this->saveMap($row);
     }
 
-    $this->assertSame($num_error_rows, (int) $this->getIdMap()->errorCount());
+    $this->assertSame($num_error_rows, $this->getIdMap()->errorCount());
   }
 
   /**

core/modules/migrate/tests/src/Unit/MigrateTestCase.php

@@ -78,11 +78,6 @@ abstract class MigrateTestCase extends UnitTestCase {
 
     $configuration = &$this->migrationConfiguration;
 
-    $migration->method('getHighWaterProperty')
-      ->willReturnCallback(function () use ($configuration) {
-        return isset($configuration['high_water_property']) ? $configuration['high_water_property'] : '';
-      });
-
     $migration->method('set')
       ->willReturnCallback(function ($argument, $value) use (&$configuration) {
         $configuration[$argument] = $value;

core/modules/migrate/tests/src/Unit/MigrationTest.php

@@ -19,7 +19,7 @@ use Drupal\Tests\UnitTestCase;
 /**
  * @coversDefaultClass \Drupal\migrate\Plugin\Migration
  *
- * @group Migration
+ * @group migrate
  */
 class MigrationTest extends UnitTestCase {
 

core/modules/migrate/tests/src/Unit/Plugin/migrate/destination/EntityContentBaseTest.php

@@ -8,9 +8,9 @@
 namespace Drupal\Tests\migrate\Unit\Plugin\migrate\destination;
 
 use Drupal\Core\Entity\ContentEntityInterface;
-use Drupal\Core\Entity\ContentEntityType;
 use Drupal\Core\Entity\EntityManagerInterface;
 use Drupal\Core\Entity\EntityStorageInterface;
+use Drupal\Core\Entity\EntityTypeInterface;
 use Drupal\Core\Field\BaseFieldDefinition;
 use Drupal\Core\Field\FieldTypePluginManagerInterface;
 use Drupal\migrate\MigrateException;
@@ -38,6 +38,11 @@ class EntityContentBaseTest extends UnitTestCase {
    */
   protected $storage;
 
+  /**
+   * @var \Drupal\Core\Entity\EntityTypeInterface
+   */
+  protected $entityType;
+
   /**
    * @var \Drupal\Core\Entity\EntityManagerInterface
    */
@@ -51,6 +56,11 @@ class EntityContentBaseTest extends UnitTestCase {
 
     $this->migration = $this->prophesize(MigrationInterface::class);
     $this->storage = $this->prophesize(EntityStorageInterface::class);
+
+    $this->entityType = $this->prophesize(EntityTypeInterface::class);
+    $this->entityType->getPluralLabel()->willReturn('wonkiness');
+    $this->storage->getEntityType()->willReturn($this->entityType->reveal());
+
     $this->entityManager = $this->prophesize(EntityManagerInterface::class);
   }
 
@@ -104,14 +114,11 @@ class EntityContentBaseTest extends UnitTestCase {
    */
   public function testUntranslatable() {
     // An entity type without a language.
-    $entity_type = $this->prophesize(ContentEntityType::class);
-    $entity_type->getKey('langcode')->willReturn('');
-    $entity_type->getKey('id')->willReturn('id');
+    $this->entityType->getKey('langcode')->willReturn('');
+    $this->entityType->getKey('id')->willReturn('id');
     $this->entityManager->getBaseFieldDefinitions('foo')
       ->willReturn(['id' => BaseFieldDefinitionTest::create('integer')]);
 
-    $this->storage->getEntityType()->willReturn($entity_type->reveal());
-
     $destination = new EntityTestDestination(
       ['translations' => TRUE],
       '',

core/modules/migrate/tests/src/Unit/destination/EntityRevisionTest.php

@@ -9,6 +9,7 @@ namespace Drupal\Tests\migrate\Unit\destination;
 
 use Drupal\Core\Entity\ContentEntityInterface;
 use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Entity\EntityTypeInterface;
 use Drupal\migrate\Plugin\MigrationInterface;
 use Drupal\migrate\Plugin\migrate\destination\EntityRevision as RealEntityRevision;
 use Drupal\migrate\Row;
@@ -48,6 +49,12 @@ class EntityRevisionTest extends UnitTestCase {
     // Setup mocks to be used when creating a revision destination.
     $this->migration = $this->prophesize(MigrationInterface::class);
     $this->storage = $this->prophesize('\Drupal\Core\Entity\EntityStorageInterface');
+
+    $entity_type = $this->prophesize(EntityTypeInterface::class);
+    $entity_type->getSingularLabel()->willReturn('crazy');
+    $entity_type->getPluralLabel()->willReturn('craziness');
+    $this->storage->getEntityType()->willReturn($entity_type->reveal());
+
     $this->entityManager = $this->prophesize('\Drupal\Core\Entity\EntityManagerInterface');
     $this->fieldTypeManager = $this->prophesize('\Drupal\Core\Field\FieldTypePluginManagerInterface');
   }

core/modules/migrate/tests/src/Unit/destination/PerComponentEntityDisplayTest.php

@@ -44,8 +44,8 @@ class PerComponentEntityDisplayTest extends MigrateTestCase {
       ->method('save')
       ->with();
     $plugin = new TestPerComponentEntityDisplay($entity);
-    $this->assertSame($plugin->import($row), ['entity_type_test', 'bundle_test', 'view_mode_test', 'field_name_test']);
-    $this->assertSame($plugin->getTestValues(), ['entity_type_test', 'bundle_test', 'view_mode_test']);
+    $this->assertSame(['entity_type_test', 'bundle_test', 'view_mode_test', 'field_name_test'], $plugin->import($row));
+    $this->assertSame(['entity_type_test', 'bundle_test', 'view_mode_test'], $plugin->getTestValues());
   }
 
 }

core/modules/migrate/tests/src/Unit/destination/PerComponentEntityFormDisplayTest.php

@@ -44,8 +44,8 @@ class PerComponentEntityFormDisplayTest extends MigrateTestCase {
       ->method('save')
       ->with();
     $plugin = new TestPerComponentEntityFormDisplay($entity);
-    $this->assertSame($plugin->import($row), ['entity_type_test', 'bundle_test', 'form_mode_test', 'field_name_test']);
-    $this->assertSame($plugin->getTestValues(), ['entity_type_test', 'bundle_test', 'form_mode_test']);
+    $this->assertSame(['entity_type_test', 'bundle_test', 'form_mode_test', 'field_name_test'], $plugin->import($row));
+    $this->assertSame(['entity_type_test', 'bundle_test', 'form_mode_test'], $plugin->getTestValues());
   }
 
 }

core/modules/migrate/tests/src/Unit/process/CallbackTest.php

@@ -30,7 +30,7 @@ class CallbackTest extends MigrateProcessTestCase {
   public function testCallbackWithFunction() {
     $this->plugin->setCallable('strtolower');
     $value = $this->plugin->transform('FooBar', $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, 'foobar');
+    $this->assertSame('foobar', $value);
   }
 
   /**
@@ -39,7 +39,7 @@ class CallbackTest extends MigrateProcessTestCase {
   public function testCallbackWithClassMethod() {
     $this->plugin->setCallable(['\Drupal\Component\Utility\Unicode', 'strtolower']);
     $value = $this->plugin->transform('FooBar', $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, 'foobar');
+    $this->assertSame('foobar', $value);
   }
 
 }

core/modules/migrate/tests/src/Unit/process/ConcatTest.php

@@ -30,7 +30,7 @@ class ConcatTest extends MigrateProcessTestCase {
    */
   public function testConcatWithoutDelimiter() {
     $value = $this->plugin->transform(['foo', 'bar'], $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, 'foobar');
+    $this->assertSame('foobar', $value);
   }
 
   /**
@@ -47,7 +47,7 @@ class ConcatTest extends MigrateProcessTestCase {
   public function testConcatWithDelimiter() {
     $this->plugin->setDelimiter('_');
     $value = $this->plugin->transform(['foo', 'bar'], $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, 'foo_bar');
+    $this->assertSame('foo_bar', $value);
   }
 
 }

core/modules/migrate/tests/src/Unit/process/ExplodeTest.php

@@ -29,7 +29,7 @@ class ExplodeTest extends MigrateProcessTestCase {
    */
   public function testTransform() {
     $value = $this->plugin->transform('foo,bar,tik', $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, ['foo', 'bar', 'tik']);
+    $this->assertSame(['foo', 'bar', 'tik'], $value);
   }
 
   /**
@@ -38,7 +38,7 @@ class ExplodeTest extends MigrateProcessTestCase {
   public function testTransformLimit() {
     $plugin = new Explode(['delimiter' => '_', 'limit' => 2], 'map', []);
     $value = $plugin->transform('foo_bar_tik', $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, ['foo', 'bar_tik']);
+    $this->assertSame(['foo', 'bar_tik'], $value);
   }
 
   /**
@@ -49,7 +49,7 @@ class ExplodeTest extends MigrateProcessTestCase {
 
     $concat = new Concat([], 'map', []);
     $concatenated = $concat->transform($exploded, $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($concatenated, 'foobartik');
+    $this->assertSame('foobartik', $concatenated);
   }
 
   /**

core/modules/migrate/tests/src/Unit/process/ExtractTest.php

@@ -25,7 +25,7 @@ class ExtractTest extends MigrateProcessTestCase {
    */
   public function testExtract() {
     $value = $this->plugin->transform(['foo' => 'bar'], $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, 'bar');
+    $this->assertSame('bar', $value);
   }
 
   /**
@@ -50,7 +50,7 @@ class ExtractTest extends MigrateProcessTestCase {
   public function testExtractFailDefault() {
     $plugin = new Extract(['index' => ['foo'], 'default' => 'test'], 'map', []);
     $value = $plugin->transform(['bar' => 'foo'], $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, 'test', '');
+    $this->assertSame('test', $value, '');
   }
 
 }

core/modules/migrate/tests/src/Unit/process/FlattenTest.php

@@ -17,7 +17,7 @@ class FlattenTest extends MigrateProcessTestCase {
   public function testFlatten() {
     $plugin = new Flatten([], 'flatten', []);
     $flattened = $plugin->transform([1, 2, [3, 4, [5]], [], [7, 8]], $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($flattened, [1, 2, 3, 4, 5, 7, 8]);
+    $this->assertSame([1, 2, 3, 4, 5, 7, 8], $flattened);
   }
 
 }

core/modules/migrate/tests/src/Unit/process/FormatDateTest.php

@@ -56,6 +56,40 @@ class FormatDateTest extends MigrateProcessTestCase {
     $this->plugin->transform('January 5, 1955', $this->migrateExecutable, $this->row, 'field_date');
   }
 
+  /**
+   * Tests that "timezone" configuration key triggers deprecation error.
+   *
+   * @covers ::transform
+   *
+   * @dataProvider providerTestDeprecatedTimezoneConfigurationKey
+   *
+   * @group legacy
+   * @expectedDeprecation Configuration key "timezone" is deprecated in 8.4.x and will be removed before Drupal 9.0.0, use "from_timezone" and "to_timezone" instead. See https://www.drupal.org/node/2885746
+   */
+  public function testDeprecatedTimezoneConfigurationKey($configuration, $value, $expected) {
+    $this->plugin = new FormatDate($configuration, 'test_format_date', []);
+    $actual = $this->plugin->transform($value, $this->migrateExecutable, $this->row, 'field_date');
+
+    $this->assertEquals($expected, $actual);
+  }
+
+  /**
+   * Data provider for testDeprecatedTimezoneConfigurationKey.
+   */
+  public function providerTestDeprecatedTimezoneConfigurationKey() {
+    return [
+      [
+        'configuration' => [
+          'from_format' => 'Y-m-d\TH:i:sO',
+          'to_format' => 'c e',
+          'timezone' => 'America/Managua',
+        ],
+        'value' => '2004-12-19T10:19:42-0600',
+        'expected' => '2004-12-19T10:19:42-06:00 -06:00'
+      ],
+    ];
+  }
+
   /**
    * Tests transformation.
    *
@@ -96,10 +130,10 @@ class FormatDateTest extends MigrateProcessTestCase {
       'datetime_datetime' => [
         'configuration' => [
           'from_format' => 'm/d/Y H:i:s',
-          'to_format' => 'Y-m-d\TH:i:s',
+          'to_format' => 'Y-m-d\TH:i:s e',
         ],
         'value' => '01/05/1955 10:43:22',
-        'expected' => '1955-01-05T10:43:22',
+        'expected' => '1955-01-05T10:43:22 Australia/Sydney',
       ],
       'empty_values' => [
         'configuration' => [
@@ -109,14 +143,37 @@ class FormatDateTest extends MigrateProcessTestCase {
         'value' => '',
         'expected' => '',
       ],
-      'timezone' => [
+      'timezone_from_to' => [
         'configuration' => [
-          'from_format' => 'Y-m-d\TH:i:sO',
-          'to_format' => 'Y-m-d\TH:i:s',
-          'timezone' => 'America/Managua',
+          'from_format' => 'Y-m-d H:i:s',
+          'to_format' => 'Y-m-d H:i:s e',
+          'from_timezone' => 'America/Managua',
+          'to_timezone' => 'UTC',
         ],
-        'value' => '2004-12-19T10:19:42-0600',
-        'expected' => '2004-12-19T10:19:42',
+        'value' => '2004-12-19 10:19:42',
+        'expected' => '2004-12-19 16:19:42 UTC',
+      ],
+      'timezone_from' => [
+        'configuration' => [
+          'from_format' => 'Y-m-d h:i:s',
+          'to_format' => 'Y-m-d h:i:s e',
+          'from_timezone' => 'America/Managua',
+        ],
+        'value' => '2004-11-19 10:25:33',
+        // Unit tests use Australia/Sydney timezone, so date value will be
+        // converted from America/Managua to Australia/Sydney timezone.
+        'expected' => '2004-11-20 03:25:33 Australia/Sydney',
+      ],
+      'timezone_to' => [
+        'configuration' => [
+          'from_format' => 'Y-m-d H:i:s',
+          'to_format' => 'Y-m-d H:i:s e',
+          'to_timezone' => 'America/Managua',
+        ],
+        'value' => '2004-12-19 10:19:42',
+        // Unit tests use Australia/Sydney timezone, so date value will be
+        // converted from Australia/Sydney to America/Managua timezone.
+        'expected' => '2004-12-18 17:19:42 America/Managua',
       ],
     ];
   }

core/modules/migrate/tests/src/Unit/process/GetTest.php

@@ -34,7 +34,7 @@ class GetTest extends MigrateProcessTestCase {
       ->will($this->returnValue('source_value'));
     $this->plugin->setSource('test');
     $value = $this->plugin->transform(NULL, $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, 'source_value');
+    $this->assertSame('source_value', $value);
   }
 
   /**
@@ -52,7 +52,7 @@ class GetTest extends MigrateProcessTestCase {
         return $map[$argument];
       }));
     $value = $this->plugin->transform(NULL, $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, ['source_value1', 'source_value2']);
+    $this->assertSame(['source_value1', 'source_value2'], $value);
   }
 
   /**
@@ -65,7 +65,7 @@ class GetTest extends MigrateProcessTestCase {
       ->will($this->returnValue('source_value'));
     $this->plugin->setSource('@@test');
     $value = $this->plugin->transform(NULL, $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, 'source_value');
+    $this->assertSame('source_value', $value);
   }
 
   /**
@@ -85,7 +85,7 @@ class GetTest extends MigrateProcessTestCase {
         return $map[$argument];
       }));
     $value = $this->plugin->transform(NULL, $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, ['source_value1', 'source_value2', 'source_value3', 'source_value4']);
+    $this->assertSame(['source_value1', 'source_value2', 'source_value3', 'source_value4'], $value);
   }
 
   /**

core/modules/migrate/tests/src/Unit/process/IteratorTest.php

@@ -75,10 +75,10 @@ class IteratorTest extends MigrateTestCase {
     // values ended up in the proper destinations, and that the value of the
     // key (@id) is the same as the destination ID (42).
     $new_value = $plugin->transform($current_value, $migrate_executable, $row, 'test');
-    $this->assertSame(count($new_value), 1);
-    $this->assertSame(count($new_value[42]), 2);
-    $this->assertSame($new_value[42]['foo'], 'test');
-    $this->assertSame($new_value[42]['id'], 42);
+    $this->assertSame(1, count($new_value));
+    $this->assertSame(2, count($new_value[42]));
+    $this->assertSame('test', $new_value[42]['foo']);
+    $this->assertSame(42, $new_value[42]['id']);
   }
 
 }

core/modules/migrate/tests/src/Unit/process/MigrationLookupTest.php

@@ -11,6 +11,7 @@ use Drupal\migrate\Plugin\MigrateIdMapInterface;
 use Drupal\migrate\Plugin\MigratePluginManager;
 use Drupal\migrate\Plugin\MigrateSourceInterface;
 use Drupal\migrate\Plugin\MigrationPluginManagerInterface;
+use Drupal\migrate\Row;
 use Prophecy\Argument;
 
 /**
@@ -100,6 +101,8 @@ class MigrationLookupTest extends MigrateProcessTestCase {
       'migration' => 'foobaz',
     ];
     $migration_plugin->id()->willReturn(uniqid());
+    $migration_plugin_manager->createInstances(['foobaz'])
+      ->willReturn(['foobaz' => $migration_plugin->reveal()]);
     $migration = new MigrationLookup($configuration, 'migration_lookup', [], $migration_plugin->reveal(), $migration_plugin_manager->reveal(), $process_plugin_manager->reveal());
     $this->setExpectedException(MigrateSkipProcessException::class);
     $migration->transform(0, $this->migrateExecutable, $this->row, 'foo');
@@ -238,4 +241,61 @@ class MigrationLookupTest extends MigrateProcessTestCase {
     $migration->transform(1, $this->migrateExecutable, $this->row, '');
   }
 
+  /**
+   * Tests processing multiple source IDs.
+   */
+  public function testMultipleSourceIds() {
+    $migration_plugin = $this->prophesize(MigrationInterface::class);
+    $migration_plugin_manager = $this->prophesize(MigrationPluginManagerInterface::class);
+    $process_plugin_manager = $this->prophesize(MigratePluginManager::class);
+    $foobaz_migration = $this->prophesize(MigrationInterface::class);
+    $get_migration = $this->prophesize(MigrationLookup::class);
+    $id_map = $this->prophesize(MigrateIdMapInterface::class);
+    $destination_plugin = $this->prophesize(MigrateDestinationInterface::class);
+    $source_plugin = $this->prophesize(MigrateSourceInterface::class);
+
+    $migration_plugin_manager->createInstances(['foobaz'])
+      ->willReturn(['foobaz' => $foobaz_migration->reveal()]);
+
+    $process_plugin_manager->createInstance('get', ['source' => ['string_id', 'integer_id']], $migration_plugin->reveal())
+      ->willReturn($get_migration->reveal());
+
+    $foobaz_migration->getIdMap()->willReturn($id_map->reveal());
+    $foobaz_migration->getDestinationPlugin(TRUE)->willReturn($destination_plugin->reveal());
+    $foobaz_migration->getProcess()->willReturn([]);
+    $foobaz_migration->getSourcePlugin()->willReturn($source_plugin->reveal());
+    $foobaz_migration->id()->willReturn('foobaz');
+    $foobaz_migration->getSourceConfiguration()->willReturn([]);
+
+    $get_migration->transform(NULL, $this->migrateExecutable, $this->row, 'foo')
+      ->willReturn(['example_string', 99]);
+
+    $source_plugin_ids = [
+      'string_id' => [
+        'type' => 'string',
+        'max_length' => 128,
+        'is_ascii' => TRUE,
+        'alias' => 'wpt',
+      ],
+      'integer_id' => [
+        'type' => 'integer',
+        'unsigned' => FALSE,
+        'alias' => 'wpt',
+      ],
+    ];
+
+    $stub_row = new Row(['string_id' => 'example_string', 'integer_id' => 99], $source_plugin_ids, TRUE);
+    $destination_plugin->import($stub_row)->willReturn([2]);
+
+    $source_plugin->getIds()->willReturn($source_plugin_ids);
+
+    $configuration = [
+      'migration' => 'foobaz',
+      'source_ids' => ['foobaz' => ['string_id', 'integer_id']],
+    ];
+    $migration = new MigrationLookup($configuration, 'migration', [], $migration_plugin->reveal(), $migration_plugin_manager->reveal(), $process_plugin_manager->reveal());
+    $result = $migration->transform(NULL, $this->migrateExecutable, $this->row, 'foo');
+    $this->assertEquals(2, $result);
+  }
+
 }

core/modules/migrate/tests/src/Unit/process/MigrationTest.php

@@ -124,6 +124,8 @@ class MigrationTest extends MigrateProcessTestCase {
       'migration' => 'foobaz',
     ];
     $this->migration_plugin->id()->willReturn(uniqid());
+    $this->migration_plugin_manager->createInstances(['foobaz'])
+      ->willReturn(['foobaz' => $this->migration_plugin->reveal()]);
     $migration = new Migration($configuration, 'migration', [], $this->migration_plugin->reveal(), $this->migration_plugin_manager->reveal(), $this->process_plugin_manager->reveal());
     $this->setExpectedException(MigrateSkipProcessException::class);
     $migration->transform(0, $this->migrateExecutable, $this->row, 'foo');

core/modules/migrate/tests/src/Unit/process/SkipOnEmptyTest.php

@@ -31,7 +31,7 @@ class SkipOnEmptyTest extends MigrateProcessTestCase {
     $configuration['method'] = 'process';
     $value = (new SkipOnEmpty($configuration, 'skip_on_empty', []))
       ->transform(' ', $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, ' ');
+    $this->assertSame(' ', $value);
   }
 
   /**
@@ -51,7 +51,7 @@ class SkipOnEmptyTest extends MigrateProcessTestCase {
     $configuration['method'] = 'row';
     $value = (new SkipOnEmpty($configuration, 'skip_on_empty', []))
       ->transform(' ', $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, ' ');
+    $this->assertSame(' ', $value);
   }
 
   /**

core/modules/migrate/tests/src/Unit/process/StaticMapTest.php

@@ -27,7 +27,7 @@ class StaticMapTest extends MigrateProcessTestCase {
    */
   public function testMapWithSourceString() {
     $value = $this->plugin->transform('foo', $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, ['bar' => 'baz']);
+    $this->assertSame(['bar' => 'baz'], $value);
   }
 
   /**
@@ -35,7 +35,7 @@ class StaticMapTest extends MigrateProcessTestCase {
    */
   public function testMapWithSourceList() {
     $value = $this->plugin->transform(['foo', 'bar'], $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, 'baz');
+    $this->assertSame('baz', $value);
   }
 
   /**
@@ -62,7 +62,7 @@ class StaticMapTest extends MigrateProcessTestCase {
     $configuration['default_value'] = 'test';
     $this->plugin = new StaticMap($configuration, 'map', []);
     $value = $this->plugin->transform(['bar'], $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, 'test');
+    $this->assertSame('test', $value);
   }
 
   /**

core/modules/migrate/tests/src/Unit/process/SubProcessTest.php

@@ -73,10 +73,10 @@ class SubProcessTest extends MigrateTestCase {
     // values ended up in the proper destinations, and that the value of the
     // key (@id) is the same as the destination ID (42).
     $new_value = $plugin->transform($current_value, $migrate_executable, $row, 'test');
-    $this->assertSame(count($new_value), 1);
-    $this->assertSame(count($new_value[42]), 2);
-    $this->assertSame($new_value[42]['foo'], 'test');
-    $this->assertSame($new_value[42]['id'], 42);
+    $this->assertSame(1, count($new_value));
+    $this->assertSame(2, count($new_value[42]));
+    $this->assertSame('test', $new_value[42]['foo']);
+    $this->assertSame(42, $new_value[42]['id']);
   }
 
 }

core/modules/migrate/tests/src/Unit/process/UrlEncodeTest.php

@@ -4,7 +4,6 @@ namespace Drupal\Tests\migrate\Unit\process;
 
 use Drupal\migrate\Plugin\migrate\process\UrlEncode;
 use Drupal\migrate\MigrateExecutable;
-use Drupal\migrate\MigrateMessage;
 use Drupal\migrate\Row;
 use Drupal\Tests\migrate\Unit\MigrateTestCase;
 
@@ -56,7 +55,7 @@ class UrlEncodeTest extends MigrateTestCase {
    *   Encoded URL.
    */
   protected function doTransform($value) {
-    $executable = new MigrateExecutable($this->getMigration(), new MigrateMessage());
+    $executable = new MigrateExecutable($this->getMigration());
     $row = new Row();
 
     return (new UrlEncode([], 'urlencode', []))