Delete users not in D7.

src/Commands/DrushCommands.php

@@ -2,6 +2,7 @@
 
 namespace Drupal\drupalorg_migrate\Commands;
 
+use Drupal\Core\Database\Database;
 use Drush\Commands\DrushCommands as BaseDrushCommands;
 
 /**
@@ -18,7 +19,106 @@ class DrushCommands extends BaseDrushCommands {
    * @usage drush drupalorg_migrate:sync-users
    */
   public function syncUsers() {
-    dd('hi');
+    $db_connection = Database::getConnection();
+    $d7_connection = Database::getConnection('default', 'migrate');
+
+    $count_users_d7 = $d7_connection->select('users')->countQuery()->execute()->fetchField();
+    $count_users = $db_connection->select('users')->countQuery()->execute()->fetchField();
+    if ($count_users !== $count_users_d7) {
+      // Mismatch of users between Drupal 7 and modern Drupal.
+      $this->logger()->warning(\dt('Users counts are different in D7 and the new system. @count (new) vs @count_d7 (D7).', [
+        '@count' => $count_users,
+        '@count_d7' => $count_users_d7,
+      ]));
+
+      // Memory usage around 22MB for 10000.
+      $length = 10000;
+      $offset = 0;
+      $extra_users = [];
+
+      // Users are migrated from D7 to D10+, so any user present on D10+ that
+      // is not in D7, means that the user account was removed.
+      $user_ids = $this->getNextBatch($offset, $length);
+      $this->io()->progressStart($count_users);
+      while (!empty($user_ids)) {
+        $user_ids_not_in_d7 = $this->userIdsNotInD7($user_ids);
+        $extra_users = array_merge($extra_users, $user_ids_not_in_d7);
+
+        $this->io()->progressAdvance($length);
+
+        $offset += $length;
+        $user_ids = $this->getNextBatch($offset, $length);
+      }
+      $this->io()->progressFinish();
+
+      if (empty($extra_users)) {
+        $this->logger()->success('Users are in sync');
+      }
+      else {
+        $this->logger()->warning(\dt('Users are NOT in sync. @count user(s) will be deleted.', [
+          '@count' => count($extra_users),
+        ]));
+        foreach ($extra_users as $extra_user_uid) {
+          // No need for extra logging as the user_cancel function does it.
+          user_cancel([], $extra_user_uid, 'user_cancel_reassign');
+          // Since user_cancel() is not invoked via Form API, batch processing
+          // needs to be invoked manually.
+          $batch =& batch_get();
+          // Mark this batch as non-progressive to bypass the progress bar and
+          // redirect.
+          $batch['progressive'] = FALSE;
+          // Batch it the drush way.
+          // batch_process();
+          drush_backend_batch_process();
+        }
+      }
+    }
+    else {
+      $this->logger()->success('Users are in sync');
+    }
+  }
+
+  /**
+   * Get a batch of user ids to check.
+   *
+   * @param int $offset
+   *   Offset of the records to get.
+   * @param int $length
+   *   Length of the records to get.
+   *
+   * @return array
+   *   Array of user ids.
+   */
+  protected function getNextBatch($offset, $length) {
+    $connection = Database::getConnection();
+    return $connection
+      ->select('users', 'u')
+      ->fields('u', ['uid'])
+      ->range($offset, $length)
+      ->orderBy('u.uid')
+      ->execute()
+      ->fetchCol();
+  }
+
+  /**
+   * Check which user ids are not in D7.
+   *
+   * @param array $uids
+   *   List of user ids to check
+   *
+   * @return array
+   *   Array of user ids not present in D7.
+   */
+  protected function userIdsNotInD7($uids) {
+    $d7_connection = Database::getConnection('default', 'migrate');
+    $matched_uids = $d7_connection
+      ->select('users', 'u')
+      ->fields('u', ['uid'])
+      ->condition('u.uid', $uids, 'IN')
+      ->orderBy('u.uid')
+      ->execute()
+      ->fetchCol();
+    return array_diff($uids, $matched_uids);
   }
 
 }