Issue #2639254 by dawehner, heddn: Make it possible to skip empty migration destinations

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

@@ -102,6 +102,10 @@ class Migration extends ProcessPluginBase implements ContainerFactoryPluginInter
       }
     }
 
+    if (!$destination_ids && !empty($this->configuration['no_stub'])) {
+      return NULL;
+    }
+
     if (!$destination_ids && ($self || isset($this->configuration['stub_id']) || count($migrations) == 1)) {
       // If the lookup didn't succeed, figure out which migration will do the
       // stubbing.

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

@@ -0,0 +1,92 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\migrate\Unit\process\MigrationTest.
+ */
+
+namespace Drupal\Tests\migrate\Unit\process;
+
+use Drupal\Core\Entity\EntityStorageInterface;
+use Drupal\migrate\Entity\MigrationInterface;
+use Drupal\migrate\Plugin\migrate\process\Migration;
+use Drupal\migrate\Plugin\migrate\source\SourcePluginBase;
+use Drupal\migrate\Plugin\MigrateDestinationInterface;
+use Drupal\migrate\Plugin\MigrateIdMapInterface;
+use Drupal\migrate\Plugin\MigratePluginManager;
+use Drupal\migrate\Plugin\MigrateSourceInterface;
+use Prophecy\Argument;
+
+/**
+ * @coversDefaultClass \Drupal\migrate\Plugin\migrate\process\Migration
+ * @group migrate
+ */
+class MigrationTest extends MigrateProcessTestCase {
+
+  /**
+   * @covers ::transform
+   */
+  public function testTransformWithStubSkipping() {
+    $migration_entity = $this->prophesize(MigrationInterface::class);
+    $migration_storage = $this->prophesize(EntityStorageInterface::class);
+    $process_plugin_manager = $this->prophesize(MigratePluginManager::class);
+
+    $destination_id_map = $this->prophesize(MigrateIdMapInterface::class);
+    $destination_migration = $this->prophesize(MigrationInterface::class);
+    $destination_migration->getIdMap()->willReturn($destination_id_map->reveal());
+    $migration_storage->loadMultiple(['destination_migration'])
+      ->willReturn(['destination_migration' => $destination_migration->reveal()]);
+    $destination_id_map->lookupDestinationId([1])->willReturn(NULL);
+
+    $configuration = [
+      'no_stub' => TRUE,
+      'migration' => 'destination_migration',
+    ];
+
+    $migration_entity->id()->willReturn('actual_migration');
+    $destination_migration->getDestinationPlugin(TRUE)->shouldNotBeCalled();
+
+    $migration = new Migration($configuration, '', [], $migration_entity->reveal(), $migration_storage->reveal(), $process_plugin_manager->reveal());
+    $result = $migration->transform(1, $this->migrateExecutable, $this->row, '');
+    $this->assertNull($result);
+  }
+
+  /**
+   * @covers ::transform
+   */
+  public function testTransformWithStubbing() {
+    $migration_entity = $this->prophesize(MigrationInterface::class);
+    $migration_storage = $this->prophesize(EntityStorageInterface::class);
+    $process_plugin_manager = $this->prophesize(MigratePluginManager::class);
+
+    $destination_id_map = $this->prophesize(MigrateIdMapInterface::class);
+    $destination_migration = $this->prophesize(MigrationInterface::class);
+    $destination_migration->getIdMap()->willReturn($destination_id_map->reveal());
+    $migration_storage->loadMultiple(['destination_migration'])
+      ->willReturn(['destination_migration' => $destination_migration->reveal()]);
+    $destination_id_map->lookupDestinationId([1])->willReturn(NULL);
+
+    $configuration = [
+      'no_stub' => FALSE,
+      'migration' => 'destination_migration',
+    ];
+
+    $migration_entity->id()->willReturn('actual_migration');
+    $destination_migration->id()->willReturn('destination_migration');
+    $destination_migration->getDestinationPlugin(TRUE)->shouldBeCalled();
+    $destination_migration->get('process')->willReturn([]);
+    $destination_migration->get('source')->willReturn([]);
+
+    $source_plugin = $this->prophesize(MigrateSourceInterface::class);
+    $source_plugin->getIds()->willReturn(['nid']);
+    $destination_migration->getSourcePlugin()->willReturn($source_plugin->reveal());
+    $destination_plugin = $this->prophesize(MigrateDestinationInterface::class);
+    $destination_plugin->import(Argument::any())->willReturn([2]);
+    $destination_migration->getDestinationPlugin(TRUE)->willReturn($destination_plugin->reveal());
+
+    $migration = new Migration($configuration, '', [], $migration_entity->reveal(), $migration_storage->reveal(), $process_plugin_manager->reveal());
+    $result = $migration->transform(1, $this->migrateExecutable, $this->row, '');
+    $this->assertEquals(2, $result);
+  }
+
+}