Issue #3275474: Update README instructions for testing the module

automatic_updates_extensions/src/Form/UpdateReady.php

+<?php
+
+namespace Drupal\automatic_updates_extensions\Form;
+
+use Drupal\automatic_updates_extensions\BatchProcessor;
+use Drupal\automatic_updates\BatchProcessor as AutoUpdatesBatchProcessor;
+use Drupal\automatic_updates_extensions\ExtensionUpdater;
+use Drupal\Core\Batch\BatchBuilder;
+use Drupal\Core\Extension\ModuleExtensionList;
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Messenger\MessengerInterface;
+use Drupal\Core\State\StateInterface;
+use Drupal\package_manager\Exception\StageException;
+use Drupal\package_manager\Exception\StageOwnershipException;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Defines a form to commit staged updates.
+ *
+ * @internal
+ *   Form classes are internal.
+ */
+class UpdateReady extends FormBase {
+
+  /**
+   * The updater service.
+   *
+   * @var \Drupal\automatic_updates_extensions\ExtensionUpdater
+   */
+  protected $updater;
+
+  /**
+   * The state service.
+   *
+   * @var \Drupal\Core\State\StateInterface
+   */
+  protected $state;
+
+  /**
+   * The module list service.
+   *
+   * @var \Drupal\Core\Extension\ModuleExtensionList
+   */
+  protected $moduleList;
+
+  /**
+   * Constructs a new UpdateReady object.
+   *
+   * @param \Drupal\automatic_updates_extensions\ExtensionUpdater $updater
+   *   The updater service.
+   * @param \Drupal\Core\Messenger\MessengerInterface $messenger
+   *   The messenger service.
+   * @param \Drupal\Core\State\StateInterface $state
+   *   The state service.
+   * @param \Drupal\Core\Extension\ModuleExtensionList $module_list
+   *   The module list service.
+   */
+  public function __construct(ExtensionUpdater $updater, MessengerInterface $messenger, StateInterface $state, ModuleExtensionList $module_list) {
+    $this->updater = $updater;
+    $this->setMessenger($messenger);
+    $this->state = $state;
+    $this->moduleList = $module_list;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'automatic_updates_update_ready_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('automatic_updates_extensions.updater'),
+      $container->get('messenger'),
+      $container->get('state'),
+      $container->get('extension.list.module'),
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state, string $stage_id = NULL) {
+    try {
+      $this->updater->claim($stage_id);
+    }
+    catch (StageOwnershipException $e) {
+      $this->messenger()->addError($this->t('Cannot continue the update because another Composer operation is currently in progress.'));
+      return $form;
+    }
+
+    $messages = [];
+
+    // @todo Add logic to warn about possible new database updates. Determine if
+    //   \Drupal\automatic_updates\Validator\StagedDatabaseUpdateValidator
+    //   should be duplicated or changed so that it can work with other stages.
+    // @see \Drupal\automatic_updates\Validator\StagedDatabaseUpdateValidator
+    // @see \Drupal\automatic_updates\Form\UpdateReady::buildForm()
+
+    // Don't set any messages if the form has been submitted, because we don't
+    // want them to be set during form submit.
+    if (!$form_state->getUserInput()) {
+      foreach ($messages as $type => $messages_of_type) {
+        foreach ($messages_of_type as $message) {
+          $this->messenger()->addMessage($message, $type);
+        }
+      }
+    }
+
+    $form['actions'] = [
+      'cancel' => [
+        '#type' => 'submit',
+        '#value' => $this->t('Cancel update'),
+        '#submit' => ['::cancel'],
+      ],
+      '#type' => 'actions',
+    ];
+    $form['stage_id'] = [
+      '#type' => 'value',
+      '#value' => $stage_id,
+    ];
+
+    // @todo Display the project versions that will be update including any
+    //   dependencies that are Drupal projects.
+    $form['backup'] = [
+      '#prefix' => '<strong>',
+      '#markup' => $this->t('Back up your database and site before you continue. <a href=":backup_url">Learn how</a>.', [':backup_url' => 'https://www.drupal.org/node/22281']),
+      '#suffix' => '</strong>',
+    ];
+    $form['maintenance_mode'] = [
+      '#title' => $this->t('Perform updates with site in maintenance mode (strongly recommended)'),
+      '#type' => 'checkbox',
+      '#default_value' => TRUE,
+    ];
+    $form['actions']['submit'] = [
+      '#type' => 'submit',
+      '#value' => $this->t('Continue'),
+    ];
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    // Store maintenance_mode setting so we can restore it when done.
+    $this->getRequest()
+      ->getSession()
+      ->set(AutoUpdatesBatchProcessor::MAINTENANCE_MODE_SESSION_KEY, $this->state->get('system.maintenance_mode'));
+
+    if ($form_state->getValue('maintenance_mode')) {
+      $this->state->set('system.maintenance_mode', TRUE);
+    }
+    $stage_id = $form_state->getValue('stage_id');
+    $batch = (new BatchBuilder())
+      ->setTitle($this->t('Apply updates'))
+      ->setInitMessage($this->t('Preparing to apply updates'))
+      ->addOperation([BatchProcessor::class, 'commit'], [$stage_id])
+      ->addOperation([BatchProcessor::class, 'clean'], [$stage_id])
+      ->setFinishCallback([BatchProcessor::class, 'finishCommit'])
+      ->toArray();
+
+    batch_set($batch);
+  }
+
+  /**
+   * Cancels the in-progress update.
+   */
+  public function cancel(array &$form, FormStateInterface $form_state): void {
+    try {
+      $this->updater->destroy();
+      $this->messenger()->addStatus($this->t('The update was successfully cancelled.'));
+      $form_state->setRedirect('automatic_updates_extensions.report_update');
+    }
+    catch (StageException $e) {
+      $this->messenger()->addError($e->getMessage());
+    }
+  }
+
+}