Issue #2683421 by xjm, alexpott, hussainweb: Remove incremental and rollback...

  use MigrationCreationTrait;

  /**

   * If a migration has previously run, perform an incremental migration.

   */

  const MIGRATE_UPGRADE_INCREMENTAL = 1;

  /**

   * If a migration has previously run, roll it back and start fresh.

   */

  const MIGRATE_UPGRADE_ROLLBACK = 2;

  /**

   * Mapping of known migrations and their source and destination modules.

   *

    $form['#title'] = $this->t('Drupal Upgrade');

    if ($date_performed = $this->state->get('migrate_drupal_ui.performed')) {

      // @todo Add back support for rollbacks and incremental migrations.

      //   https://www.drupal.org/node/2687843

      //   https://www.drupal.org/node/2687849

      $form['upgrade_option_item'] = [

        '#type' => 'item',

        '#prefix' => $this->t('<p>An upgrade has already been performed on this site.</p>'),

        '#prefix' => $this->t('An upgrade has already been performed on this site. To perform a new migration, create a clean and empty new install of Drupal 8. Rollbacks and incremental migrations are not yet supported through the user interface. For more information, see the <a href=":url">upgrading handbook</a>.', [':url' => 'https://www.drupal.org/upgrade/migrate']),

        '#description' => $this->t('<p>Last upgrade: @date</p>', ['@date' => $this->dateFormatter->format($date_performed)]),

      ];

      $form['upgrade_option'] = array(

        '#type' => 'radios',

        '#title' => $this->t('You have two options:'),

        '#default_value' => static::MIGRATE_UPGRADE_INCREMENTAL,

        '#options' => [

          static::MIGRATE_UPGRADE_INCREMENTAL => $this->t('<strong>Rerun</strong>: Import additional configuration and content that was not available when running the upgrade previously.'),

          static::MIGRATE_UPGRADE_ROLLBACK => $this->t('<strong>Rollback</strong>: Remove content and configuration entities (such as fields and node types). Default values of other configuration will not be reverted (such as site name).'),

        ],

      );

      $validate = ['::validateCredentialForm'];

      return $form;

    }

    else {

      $form['info_header'] = [

   *   The current state of the form.

   */

  public function submitOverviewForm(array &$form, FormStateInterface $form_state) {

    switch ($form_state->getValue('upgrade_option')) {

      case static::MIGRATE_UPGRADE_INCREMENTAL:

        $form_state->setValue('step', 'confirm');

        break;

      case static::MIGRATE_UPGRADE_ROLLBACK:

        $form_state->setValue('step', 'confirm');

        break;

      default:

    $form_state->setValue('step', 'credentials');

        break;

    }

    $form_state->setRebuild();

  }

   *   The current state of the form.

   */

  public function validateCredentialForm(array &$form, FormStateInterface $form_state) {

    // Skip if rollback was chosen.

    if ($form_state->getValue('upgrade_option') == static::MIGRATE_UPGRADE_ROLLBACK) {

      return;

    }

    // Retrieve the database driver from the form, use reflection to get the

    // namespace, and then construct a valid database array the same as in

    // settings.php.

    if ($driver = $form_state->getValue('driver')) {

    $driver = $form_state->getValue('driver');

    $drivers = $this->getDatabaseTypes();

    $reflection = new \ReflectionClass($drivers[$driver]);

    $install_namespace = $reflection->getNamespaceName();

      }

      return;

    }

    }

    else {

      $database = [];

      // Migration templates that had matching tags for the source Drupal

      // version where converted to migration entities. Find one of those

      // migrations to be able to look up the matching database credentials

      // from state.

      $definitions = $this->pluginManager->getDefinitions();

      foreach ($definitions as $id => $definition) {

        /** @var \Drupal\migrate\Plugin\MigrationInterface $migration */

        $migration = $this->pluginManager->createInstance($id);

        $is_drupal_migration = FALSE;

        foreach ($migration->get('migration_tags') as $migration_tag) {

          if (substr($migration_tag, 0, 7) === 'Drupal ') {

            $is_drupal_migration = TRUE;

            break;

          }

        }

        if ($is_drupal_migration) {

          $source = $migration->get('source');

          if ($database = $this->state->get($source['database_state_key'])['database']) {

            break;

          }

        }

      }

    }

    try {

      $connection = $this->getConnection($database);

  }

  /**

   * Confirmation form for rollbacks, missing migrations, etc.

   * Confirmation form for missing migrations, etc.

   *

   * @param array $form

   *   An associative array containing the structure of the form.

    $form = parent::buildForm($form, $form_state);

    $form['actions']['submit']['#submit'] = ['::submitConfirmForm'];

    if ($rollback = $form_state->getValue('upgrade_option') == static::MIGRATE_UPGRADE_ROLLBACK) {

      $form_state->setStorage(['upgrade_option' => static::MIGRATE_UPGRADE_ROLLBACK]);

      $form['rollback'] = [

        '#markup' => $this->t('All previously imported content, as well as configuration such as field definitions, will be removed.'),

      ];

      $form['actions']['submit']['#value'] = $this->t('Perform rollback');

    }

    else {

    $form['actions']['submit']['#value'] = $this->t('Perform upgrade');

    $table_data = [];

      '#title' => '<ul><li>' . $this->t('@count available upgrade paths', ['@count' => $available_count]) . '</li><li>' . $this->t('@count missing upgrade paths', ['@count' => $missing_count]) . '</li></ul>',

      '#weight' => -15,

    ];

    }

    return $form;

  }

   */

  public function submitConfirmForm(array &$form, FormStateInterface $form_state) {

    $storage = $form_state->getStorage();

    if (isset($storage['upgrade_option']) && $storage['upgrade_option'] == static::MIGRATE_UPGRADE_ROLLBACK) {

      $migrations = $this->pluginManager->createInstances([]);

      // Assume we want all those tagged 'Drupal %'.

      foreach ($migrations as $migration_id => $migration) {

        $keep = FALSE;

        $tags = $migration->get('migration_tags');

        foreach ($tags as $tag) {

          if (strpos($tag, 'Drupal ') === 0) {

            $keep = TRUE;

            break;

          }

        }

        if (!$keep) {

          unset($migrations[$migration_id]);

        }

      }

      // Roll back in reverse order.

      $migrations = array_reverse($migrations);

      $batch = [

        'title' => $this->t('Rolling back upgrade'),

        'progress_message' => '',

        'operations' => [

          [

            [MigrateUpgradeRunBatch::class, 'run'],

            [array_keys($migrations), 'rollback', []],

          ],

        ],

        'finished' => [

          MigrateUpgradeRunBatch::class,

          'finished',

        ],

      ];

      batch_set($batch);

      $form_state->setRedirect('migrate_drupal_ui.upgrade');

      $this->state->delete('migrate_drupal_ui.performed');

    }

    else {

    $migrations = $storage['migrations'];

    $config['source_base_path'] = $storage['source_base_path'];

    $batch = [

    $form_state->setRedirect('<front>');

    $this->state->set('migrate_drupal_ui.performed', REQUEST_TIME);

  }

  }

  /**

   * Returns all supported database driver installer objects.

   * @param int[] $initial_ids

   *   The full set of migration IDs to import.

   * @param string $operation

   *   The operation to perform, 'import' or 'rollback'.

   *   The operation to perform. Only 'import' is currently supported.

   * @param array $config

   *   An array of additional configuration from the form.

   * @param array $context

   *   The batch context.

   *

   * @todo Remove the $operation parameter and conditionals for it below, and

   *   refactor this method. https://www.drupal.org/node/2687851

   */

  public static function run($initial_ids, $operation, $config, &$context) {

    if (!static::$listenersAdded) {

        $event_dispatcher->addListener(MigrateEvents::MAP_SAVE, [static::class, 'onMapSave']);

        $event_dispatcher->addListener(MigrateEvents::IDMAP_MESSAGE, [static::class, 'onIdMapMessage']);

      }

      else {

        $event_dispatcher->addListener(MigrateEvents::POST_ROW_DELETE, [static::class, 'onPostRowDelete']);

        $event_dispatcher->addListener(MigrateEvents::MAP_DELETE, [static::class, 'onMapDelete']);

      }

      static::$maxExecTime = ini_get('max_execution_time');

      if (static::$maxExecTime <= 0) {

        static::$maxExecTime = 60;

        if ($operation == 'import') {

          $migration_status = $executable->import();

        }

        else {

          $migration_status = $executable->rollback();

        }

      }

      catch (\Exception $e) {

        static::logger()->error($e->getMessage());

              $context['sandbox']['num_processed'], 'Upgraded @migration (processed 1 item total)', 'Upgraded @migration (processed @num_processed items total)',

              ['@migration' => $migration_name, '@num_processed' => $context['sandbox']['num_processed']]);

          }

          else {

            $message = static::getTranslation()->formatPlural(

              $context['sandbox']['num_processed'], 'Rolled back @migration (processed 1 item total)', 'Rolled back @migration (processed @num_processed items total)',

              ['@migration' => $migration_name, '@num_processed' => $context['sandbox']['num_processed']]);

          }

          $context['sandbox']['messages'][] = $message;

          static::logger()->notice($message);

          $context['sandbox']['num_processed'] = 0;

            '@max' => $context['sandbox']['max'],

          ]) . "<br />\n" . $context['message'];

        }

        else {

          $context['message'] = t('Currently rolling back @migration (@current of @max total tasks)', [

            '@migration' => $migration_name,

            '@current' => $context['sandbox']['current'],

            '@max' => $context['sandbox']['max'],

          ]) . "<br />\n" . $context['message'];

        }

      }

    }

    else {

      if ($results['operation'] == 'import') {

        drupal_set_message(static::getTranslation()->formatPlural($successes, 'Completed 1 upgrade task successfully', 'Completed @count upgrade tasks successfully'));

      }

      else {

        drupal_set_message(static::getTranslation()->formatPlural($successes, 'Completed 1 rollback task successfully', 'Completed @count rollback tasks successfully'));

      }

    }

    // If we had failures, log them and show the migration failed.

        drupal_set_message(static::getTranslation()->formatPlural($failures, '1 upgrade failed', '@count upgrades failed'));

        drupal_set_message(t('Upgrade process not completed'), 'error');

      }

      else {

        drupal_set_message(static::getTranslation()->formatPlural($failures, '1 rollback failed', '@count rollbacks failed'));

        drupal_set_message(t('Rollback process not completed'), 'error');

      }

    }

    else {

      if ($results['operation'] == 'import') {

        // but we didn't have failures so this is fine.

        drupal_set_message(t('Congratulations, you upgraded Drupal!'));

      }

      else {

        drupal_set_message(t('Rollback of the upgrade is complete - you may now start the upgrade process from scratch.'));

      }

    }

    if (\Drupal::moduleHandler()->moduleExists('dblog')) {