Issue #2827656 by maxocub, aditya.n: Once a process plugin returns multiple...

Issue #2827656 by maxocub, aditya.n: Once a process plugin returns multiple values, all following plugins are expected to handle multiple values

core/modules/migrate/src/MigrateExecutable.php

@@ -398,7 +398,7 @@ public function processRow(Row $row, array $process = NULL, $value = NULL) {
             $value = NULL;
             break;
           }
-          $multiple = $multiple || $plugin->multiple();
+          $multiple = $plugin->multiple();
         }
       }
       // No plugins or no value means do not set.

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

+<?php
+
+namespace Drupal\Tests\migrate\Kernel\process;
+
+use Drupal\KernelTests\KernelTestBase;
+use Drupal\migrate\MigrateExecutable;
+use Drupal\migrate\MigrateMessage;
+use Drupal\migrate\Plugin\MigrationInterface;
+
+/**
+ * Tests process pipelines with scalar and multiple values handling.
+ *
+ * @group migrate
+ */
+class HandleMultiplesTest extends KernelTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['migrate'];
+
+  /**
+   * Provides the test migration definition.
+   *
+   * @return array
+   */
+  public function getDefinition() {
+    return [
+      'source' => [
+        'plugin' => 'embedded_data',
+        'data_rows' => [],
+        'ids' => [
+          'id' => ['type' => 'string'],
+        ],
+      ],
+      'process' => [
+        // Process pipeline for testing values from string to array to string.
+        'first' => [
+          // Expects a string and returns an array.
+          [
+            'plugin' => 'explode',
+            'source' => 'scalar',
+            'delimiter' => '/',
+          ],
+          // Expects an array and returns a string.
+          [
+            'plugin' => 'extract',
+            'index' => [1],
+          ],
+          // Expects a string and returns a string.
+          [
+            'plugin' => 'callback',
+            'callable' => 'strtoupper',
+          ],
+        ],
+        // Process pipeline for testing values from array to string to array.
+        'second' => [
+          // Expects an array and returns a string.
+          [
+            'plugin' => 'extract',
+            'source' => 'multiple',
+            'index' => [1],
+          ],
+          // Expects a string and returns a string.
+          [
+            'plugin' => 'callback',
+            'callable' => 'strtoupper',
+          ],
+          // Expects a string and returns an array.
+          [
+            'plugin' => 'explode',
+            'delimiter' => '/',
+          ],
+        ],
+      ],
+      'destination' => [
+        'plugin' => 'config',
+        'config_name' => 'migrate_test.settings',
+      ],
+    ];
+  }
+
+  /**
+   * Tests process pipelines with scalar and multiple values handling.
+   *
+   * @dataProvider scalarAndMultipleValuesProviderSource
+   *
+   * @param array $source_data
+   * @param array $expected_data
+   */
+  public function testScalarAndMultipleValues(array $source_data, array $expected_data) {
+    $definition = $this->getDefinition();
+    $definition['source']['data_rows'] = [$source_data];
+
+    $migration = \Drupal::service('plugin.manager.migration')->createStubMigration($definition);
+
+    $executable = new MigrateExecutable($migration, new MigrateMessage());
+    $result = $executable->import();
+
+    // Migration needs to succeed before further assertions are made.
+    $this->assertSame(MigrationInterface::RESULT_COMPLETED, $result);
+
+    // Compare with expected data.
+    $this->assertEquals($expected_data, \Drupal::config('migrate_test.settings')->get());
+  }
+
+  /**
+   * Provides the source data with scalar and multiple values.
+   *
+   * @return array
+   */
+  public function scalarAndMultipleValuesProviderSource() {
+    return [
+      [
+        'source_data' => [
+          'id' => '1',
+          // Source value for the first pipeline.
+          'scalar' => 'foo/bar',
+          // Source value for the second pipeline.
+          'multiple' => [
+            'foo',
+            'bar/baz',
+          ],
+        ],
+        'expected_data' => [
+          // Expected value from the first pipeline.
+          'first' => 'BAR',
+          // Expected value from the second pipeline.
+          'second' => [
+            'BAR',
+            'BAZ',
+          ],
+        ],
+      ],
+    ];
+  }
+
+}