summaryrefslogtreecommitdiffstatshomepage
path: root/core/modules/system/src/Controller/DbUpdateController.php
blob: 2f5ae05120403b31658ff892b5fd803224099b0f (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
<?php

namespace Drupal\system\Controller;

use Drupal\Core\Asset\AssetQueryStringInterface;
use Drupal\Core\Batch\BatchBuilder;
use Drupal\Core\Cache\CacheBackendInterface;
use Drupal\Core\Controller\ControllerBase;
use Drupal\Core\Extension\ModuleHandlerInterface;
use Drupal\Core\Extension\Requirement\RequirementSeverity;
use Drupal\Core\KeyValueStore\KeyValueExpirableFactoryInterface;
use Drupal\Core\Render\BareHtmlPageRendererInterface;
use Drupal\Core\Session\AccountInterface;
use Drupal\Core\Site\Settings;
use Drupal\Core\State\StateInterface;
use Drupal\Core\Update\UpdateRegistry;
use Drupal\Core\Url;
use Symfony\Component\DependencyInjection\ContainerInterface;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;

/**
 * Controller routines for database update routes.
 */
class DbUpdateController extends ControllerBase {

  /**
   * The keyvalue expirable factory.
   *
   * @var \Drupal\Core\KeyValueStore\KeyValueExpirableFactoryInterface
   */
  protected $keyValueExpirableFactory;

  /**
   * A cache backend interface.
   *
   * @var \Drupal\Core\Cache\CacheBackendInterface
   */
  protected $cache;

  /**
   * The state service.
   *
   * @var \Drupal\Core\State\StateInterface
   */
  protected $state;

  /**
   * The module handler.
   *
   * @var \Drupal\Core\Extension\ModuleHandlerInterface
   */
  protected $moduleHandler;

  /**
   * The current user.
   *
   * @var \Drupal\Core\Session\AccountInterface
   */
  protected $account;

  /**
   * The bare HTML page renderer.
   *
   * @var \Drupal\Core\Render\BareHtmlPageRendererInterface
   */
  protected $bareHtmlPageRenderer;

  /**
   * The app root.
   *
   * @var string
   */
  protected $root;

  /**
   * The post update registry.
   *
   * @var \Drupal\Core\Update\UpdateRegistry
   */
  protected $postUpdateRegistry;

  /**
   * Constructs a new UpdateController.
   *
   * @param string $root
   *   The app root.
   * @param \Drupal\Core\KeyValueStore\KeyValueExpirableFactoryInterface $key_value_expirable_factory
   *   The keyvalue expirable factory.
   * @param \Drupal\Core\Cache\CacheBackendInterface $cache
   *   A cache backend interface.
   * @param \Drupal\Core\State\StateInterface $state
   *   The state service.
   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
   *   The module handler.
   * @param \Drupal\Core\Session\AccountInterface $account
   *   The current user.
   * @param \Drupal\Core\Render\BareHtmlPageRendererInterface $bare_html_page_renderer
   *   The bare HTML page renderer.
   * @param \Drupal\Core\Update\UpdateRegistry $post_update_registry
   *   The post update registry.
   * @param \Drupal\Core\Asset\AssetQueryStringInterface $assetQueryString
   *   The asset query string.
   */
  public function __construct(
    $root,
    KeyValueExpirableFactoryInterface $key_value_expirable_factory,
    CacheBackendInterface $cache,
    StateInterface $state,
    ModuleHandlerInterface $module_handler,
    AccountInterface $account,
    BareHtmlPageRendererInterface $bare_html_page_renderer,
    UpdateRegistry $post_update_registry,
    protected AssetQueryStringInterface $assetQueryString,
  ) {
    $this->root = $root;
    $this->keyValueExpirableFactory = $key_value_expirable_factory;
    $this->cache = $cache;
    $this->state = $state;
    $this->moduleHandler = $module_handler;
    $this->account = $account;
    $this->bareHtmlPageRenderer = $bare_html_page_renderer;
    $this->postUpdateRegistry = $post_update_registry;
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container) {
    return new static(
      $container->getParameter('app.root'),
      $container->get('keyvalue.expirable'),
      $container->get('cache.default'),
      $container->get('state'),
      $container->get('module_handler'),
      $container->get('current_user'),
      $container->get('bare_html_page_renderer'),
      $container->get('update.post_update_registry'),
      $container->get('asset.query_string')
    );
  }

  /**
   * Returns a database update page.
   *
   * @param string $op
   *   The update operation to perform. Can be any of the below:
   *    - "info".
   *    - "selection".
   *    - "run".
   *    - "results".
   * @param \Symfony\Component\HttpFoundation\Request $request
   *   The current request object.
   *
   * @return \Symfony\Component\HttpFoundation\Response
   *   A response object.
   */
  public function handle($op, Request $request) {
    require_once $this->root . '/core/includes/install.inc';
    require_once $this->root . '/core/includes/update.inc';

    drupal_load_updates();

    if ($request->query->get('continue')) {
      $request->getSession()->set('update_ignore_warnings', TRUE);
    }

    $regions = [];
    $requirements = update_check_requirements();
    $severity = RequirementSeverity::maxSeverityFromRequirements($requirements);
    if ($severity === RequirementSeverity::Error || ($severity === RequirementSeverity::Warning && !$request->getSession()->has('update_ignore_warnings'))) {
      $regions['sidebar_first'] = $this->updateTasksList('requirements');
      $output = $this->requirements($severity, $requirements, $request);
    }
    else {
      switch ($op) {
        case 'selection':
          $regions['sidebar_first'] = $this->updateTasksList('selection');
          $output = $this->selection($request);
          break;

        case 'run':
          $regions['sidebar_first'] = $this->updateTasksList('run');
          $output = $this->triggerBatch($request);
          break;

        case 'info':
          $regions['sidebar_first'] = $this->updateTasksList('info');
          $output = $this->info($request);
          break;

        case 'results':
          $regions['sidebar_first'] = $this->updateTasksList('results');
          $output = $this->results($request);
          break;

        // Regular batch ops : defer to batch processing API.
        default:
          require_once $this->root . '/core/includes/batch.inc';
          $regions['sidebar_first'] = $this->updateTasksList('run');
          $output = _batch_page($request);
          break;
      }
    }

    if ($output instanceof Response) {
      return $output;
    }
    $title = $output['#title'] ?? $this->t('Drupal database update');

    return $this->bareHtmlPageRenderer->renderBarePage($output, $title, 'maintenance_page', $regions);
  }

  /**
   * Returns the info database update page.
   *
   * @param \Symfony\Component\HttpFoundation\Request $request
   *   The current request.
   *
   * @return array
   *   A render array.
   */
  protected function info(Request $request) {
    // Change query-strings on css/js files to enforce reload for all users.
    $this->assetQueryString->reset();
    // Flush the cache of all data for the update status module.
    $this->keyValueExpirableFactory->get('update')->deleteAll();
    $this->keyValueExpirableFactory->get('update_available_release')->deleteAll();

    $build['info_header'] = [
      '#markup' => '<p>' . $this->t('Use this utility to update your database whenever a module, theme, or the core software is updated.') . '</p><p>' . $this->t('For more detailed information, see the <a href="https://www.drupal.org/upgrade">upgrading handbook</a>. If you are unsure what these terms mean you should probably contact your hosting provider.') . '</p>',
    ];

    $info[] = $this->t("<strong>Back up your code</strong>. Hint: when backing up module code, do not leave that backup in the 'modules' or 'sites/*/modules' directories as this may confuse Drupal's auto-discovery mechanism.");
    // @todo Simplify with https://www.drupal.org/node/2548095
    $base_url = str_replace('/update.php', '', $request->getBaseUrl());
    $info[] = $this->t('Put your site into <a href=":url">maintenance mode</a>.', [
      ':url' => Url::fromRoute('system.site_maintenance_mode')->setOption('base_url', $base_url)->toString(TRUE)->getGeneratedUrl(),
    ]);
    $info[] = $this->t('<strong>Back up your database</strong>. This process will change your database values and in case of emergency you may need to revert to a backup.');
    $info[] = $this->t('Update your files (as described in the handbook page linked above).');
    $build['info'] = [
      '#theme' => 'item_list',
      '#list_type' => 'ol',
      '#items' => $info,
    ];
    $build['info_footer'] = [
      '#markup' => '<p>' . $this->t('When you have performed the steps above, you may proceed.') . '</p>',
    ];

    $build['link'] = [
      '#type' => 'link',
      '#title' => $this->t('Continue'),
      '#attributes' => ['class' => ['button', 'button--primary']],
      // @todo Revisit once https://www.drupal.org/node/2548095 is in.
      '#url' => Url::fromUri('base://selection'),
    ];
    return $build;
  }

  /**
   * Renders a list of available database updates.
   *
   * @param \Symfony\Component\HttpFoundation\Request $request
   *   The current request.
   *
   * @return array
   *   A render array.
   */
  protected function selection(Request $request) {
    // Make sure there is no stale theme registry.
    $this->cache->deleteAll();

    $count = 0;
    $incompatible_count = 0;
    $build['start'] = [
      '#tree' => TRUE,
      '#type' => 'details',
    ];

    // Ensure system.module's updates appear first.
    $build['start']['system'] = [];

    $starting_updates = [];
    $incompatible_updates_exist = FALSE;
    $updates_per_extension = [];
    foreach (['update', 'post_update'] as $update_type) {
      switch ($update_type) {
        case 'update':
          $updates = update_get_update_list();
          break;

        case 'post_update':
          $updates = $this->postUpdateRegistry->getPendingUpdateInformation();
          break;
      }
      foreach ($updates as $extension => $update) {
        if (!isset($update['start'])) {
          $build['start'][$extension] = [
            '#type' => 'item',
            '#title' => $extension . ($this->moduleHandler->moduleExists($extension) ? ' module' : ' theme'),
            '#markup' => $update['warning'],
            '#prefix' => '<div class="messages messages--warning">',
            '#suffix' => '</div>',
          ];
          $incompatible_updates_exist = TRUE;
          continue;
        }
        if (!empty($update['pending'])) {
          $updates_per_extension += [$extension => []];
          $updates_per_extension[$extension] = array_merge($updates_per_extension[$extension], $update['pending']);
          $build['start'][$extension] = [
            '#type' => 'hidden',
            '#value' => $update['start'],
          ];
          // Store the previous items in order to merge normal updates and
          // post_update functions together.
          $build['start'][$extension] = [
            '#theme' => 'item_list',
            '#items' => $updates_per_extension[$extension],
            '#title' => $extension . ($this->moduleHandler->moduleExists($extension) ? ' module' : ' theme'),
          ];

          if ($update_type === 'update') {
            $starting_updates[$extension] = $update['start'];
          }
        }
        if (isset($update['pending'])) {
          $count = $count + count($update['pending']);
        }
      }
    }

    // Find and label any incompatible updates.
    foreach (update_resolve_dependencies($starting_updates) as $data) {
      if (!$data['allowed']) {
        $incompatible_updates_exist = TRUE;
        $incompatible_count++;
        $module_update_key = $data['module'] . '_updates';
        if (isset($build['start'][$module_update_key]['#items'][$data['number']])) {
          if ($data['missing_dependencies']) {
            $text = $this->t('This update will been skipped due to the following missing dependencies:') . '<em>' . implode(', ', $data['missing_dependencies']) . '</em>';
          }
          else {
            $text = $this->t("This update will be skipped due to an error in the module's code.");
          }
          $build['start'][$module_update_key]['#items'][$data['number']] .= '<div class="warning">' . $text . '</div>';
        }
        // Move the module containing this update to the top of the list.
        $build['start'] = [$module_update_key => $build['start'][$module_update_key]] + $build['start'];
      }
    }

    // Warn the user if any updates were incompatible.
    if ($incompatible_updates_exist) {
      $this->messenger()->addWarning($this->t('Some of the pending updates cannot be applied because their dependencies were not met.'));
    }

    if (empty($count)) {
      $this->messenger()->addStatus($this->t('No pending updates.'));
      unset($build);
      $build['links'] = [
        '#theme' => 'links',
        '#links' => $this->helpfulLinks($request),
      ];

      // No updates to run, so caches won't get flushed later.  Clear them now.
      drupal_flush_all_caches();
    }
    else {
      $build['help'] = [
        '#markup' => '<p>' . $this->t('The version of Drupal you are updating from has been automatically detected.') . '</p>',
        '#weight' => -5,
      ];
      if ($incompatible_count) {
        $build['start']['#title'] = $this->formatPlural(
          $count,
          '1 pending update (@number_applied to be applied, @number_incompatible skipped)',
          '@count pending updates (@number_applied to be applied, @number_incompatible skipped)',
          ['@number_applied' => $count - $incompatible_count, '@number_incompatible' => $incompatible_count]
        );
      }
      else {
        $build['start']['#title'] = $this->formatPlural($count, '1 pending update', '@count pending updates');
      }
      // @todo Simplify with https://www.drupal.org/node/2548095
      $base_url = str_replace('/update.php', '', $request->getBaseUrl());
      $url = (new Url('system.db_update', ['op' => 'run']))->setOption('base_url', $base_url);
      $build['link'] = [
        '#type' => 'link',
        '#title' => $this->t('Apply pending updates'),
        '#attributes' => ['class' => ['button', 'button--primary']],
        '#weight' => 5,
        '#url' => $url,
        '#access' => $url->access($this->currentUser()),
      ];
    }

    return $build;
  }

  /**
   * Displays results of the update script with any accompanying errors.
   *
   * @param \Symfony\Component\HttpFoundation\Request $request
   *   The current request.
   *
   * @return array
   *   A render array.
   */
  protected function results(Request $request) {
    // @todo Simplify with https://www.drupal.org/node/2548095
    $base_url = str_replace('/update.php', '', $request->getBaseUrl());

    // Retrieve and remove session information.
    $session = $request->getSession();
    $update_results = $session->remove('update_results');
    $update_success = $session->remove('update_success');
    $session->remove('update_ignore_warnings');

    // Report end result.
    $dblog_exists = $this->moduleHandler->moduleExists('dblog');
    if ($dblog_exists && $this->account->hasPermission('access site reports')) {
      $log_message = $this->t('All errors have been <a href=":url">logged</a>.', [
        ':url' => Url::fromRoute('dblog.overview')->setOption('base_url', $base_url)->toString(TRUE)->getGeneratedUrl(),
      ]);
    }
    else {
      $log_message = $this->t('All errors have been logged.');
    }

    if ($update_success) {
      $message = '<p>' . $this->t('Updates were attempted. If you see no failures below, you may proceed happily back to your <a href=":url">site</a>. Otherwise, you may need to update your database manually.', [':url' => Url::fromRoute('<front>')->setOption('base_url', $base_url)->toString(TRUE)->getGeneratedUrl()]) . ' ' . $log_message . '</p>';
    }
    else {
      $last = $session->get('updates_remaining');
      $last = reset($last);
      [$module, $version] = array_pop($last);
      $message = '<p class="error">' . $this->t('The update process was aborted prematurely while running <strong>update #@version in @module.module</strong>.', [
        '@version' => $version,
        '@module' => $module,
      ]) . ' ' . $log_message;
      if ($dblog_exists) {
        $message .= ' ' . $this->t('You may need to check the <code>watchdog</code> database table manually.');
      }
      $message .= '</p>';
    }

    if (Settings::get('update_free_access')) {
      $message .= '<p>' . $this->t("<strong>Reminder: don't forget to set the <code>\$settings['update_free_access']</code> value in your <code>settings.php</code> file back to <code>FALSE</code>.</strong>") . '</p>';
    }

    $build['message'] = [
      '#markup' => $message,
    ];
    $build['links'] = [
      '#theme' => 'links',
      '#links' => $this->helpfulLinks($request),
    ];

    // Output a list of info messages.
    if (!empty($update_results)) {
      $all_messages = [];
      foreach ($update_results as $extension => $updates) {
        if ($extension != '#abort') {
          $extension_has_message = FALSE;
          $info_messages = [];
          foreach ($updates as $name => $queries) {
            $messages = [];
            foreach ($queries as $query) {
              // If there is no message for this update, don't show anything.
              if (empty($query['query'])) {
                continue;
              }

              if ($query['success']) {
                $messages[] = [
                  '#wrapper_attributes' => ['class' => ['success']],
                  '#markup' => $query['query'],
                ];
              }
              else {
                $messages[] = [
                  '#wrapper_attributes' => ['class' => ['failure']],
                  '#markup' => '<strong>' . $this->t('Failed:') . '</strong> ' . $query['query'],
                ];
              }
            }

            if ($messages) {
              $extension_has_message = TRUE;
              if (is_numeric($name)) {
                $title = $this->t('Update #@count', ['@count' => $name]);
              }
              else {
                $title = $this->t('Update @name', ['@name' => trim($name, '_')]);
              }
              $info_messages[] = [
                '#theme' => 'item_list',
                '#items' => $messages,
                '#title' => $title,
              ];
            }
          }

          // If there were any messages then prefix them with the extension name
          // and add it to the global message list.
          if ($extension_has_message) {
            $header = $this->moduleHandler->moduleExists($extension) ?
              $this->t('@module module', ['@module' => $extension]) :
              $this->t('@theme theme', ['@theme' => $extension]);
            $all_messages[] = [
              '#type' => 'container',
              '#prefix' => '<h3>' . $header . '</h3>',
              '#children' => $info_messages,
            ];
          }
        }
      }
      if ($all_messages) {
        $build['query_messages'] = [
          '#type' => 'container',
          '#children' => $all_messages,
          '#attributes' => ['class' => ['update-results']],
          '#prefix' => '<h2>' . $this->t('The following updates returned messages:') . '</h2>',
        ];
      }
    }

    return $build;
  }

  /**
   * Renders a list of requirement errors or warnings.
   *
   * @param int $severity
   *   The severity of the message, as per RFC 3164.
   * @param array $requirements
   *   The array of requirement values.
   * @param \Symfony\Component\HttpFoundation\Request $request
   *   The current request.
   *
   * @return array
   *   A render array.
   */
  public function requirements($severity, array $requirements, Request $request) {
    $options = $severity === RequirementSeverity::Warning ? ['continue' => 1] : [];
    // @todo Revisit once https://www.drupal.org/node/2548095 is in. Something
    // like Url::fromRoute('system.db_update')->setOptions() should then be
    // possible.
    $try_again_url = Url::fromUri($request->getUriForPath(''))->setOptions(['query' => $options])->toString(TRUE)->getGeneratedUrl();

    $build['status_report'] = [
      '#type' => 'status_report',
      '#requirements' => $requirements,
      '#suffix' => $this->t('Check the messages and <a href=":url">try again</a>.', [':url' => $try_again_url]),
    ];

    $build['#title'] = $this->t('Requirements problem');
    return $build;
  }

  /**
   * Provides the update task list render array.
   *
   * @param string $active
   *   The active task.
   *   Can be one of 'requirements', 'info', 'selection', 'run', 'results'.
   *
   * @return array
   *   A render array.
   */
  protected function updateTasksList($active = NULL) {
    // Default list of tasks.
    $tasks = [
      'requirements' => $this->t('Verify requirements'),
      'info' => $this->t('Overview'),
      'selection' => $this->t('Review updates'),
      'run' => $this->t('Run updates'),
      'results' => $this->t('Review log'),
    ];

    $task_list = [
      '#theme' => 'maintenance_task_list',
      '#items' => $tasks,
      '#active' => $active,
    ];
    return $task_list;
  }

  /**
   * Starts the database update batch process.
   *
   * @param \Symfony\Component\HttpFoundation\Request $request
   *   The current request object.
   */
  protected function triggerBatch(Request $request) {
    $maintenance_mode = $this->state->get('system.maintenance_mode', FALSE);
    // Store the current maintenance mode status in the session so that it can
    // be restored at the end of the batch.
    $request->getSession()->set('maintenance_mode', $maintenance_mode);
    // During the update, always put the site into maintenance mode so that
    // in-progress schema changes do not affect visiting users.
    if (empty($maintenance_mode)) {
      $this->state->set('system.maintenance_mode', TRUE);
    }

    /** @var \Drupal\Core\Batch\BatchBuilder $batch_builder */
    $batch_builder = (new BatchBuilder())
      ->setTitle($this->t('Updating'))
      ->setInitMessage($this->t('Starting updates'))
      ->setErrorMessage($this->t('An unrecoverable error has occurred. You can find the error message below. It is advised to copy it to the clipboard for reference.'))
      ->setFinishCallback([DbUpdateController::class, 'batchFinished']);

    // Resolve any update dependencies to determine the actual updates that will
    // be run and the order they will be run in.
    $start = $this->getModuleUpdates();
    $updates = update_resolve_dependencies($start);

    // Store the dependencies for each update function in an array which the
    // batch API can pass in to the batch operation each time it is called. (We
    // do not store the entire update dependency array here because it is
    // potentially very large.)
    $dependency_map = [];
    foreach ($updates as $function => $update) {
      $dependency_map[$function] = !empty($update['reverse_paths']) ? array_keys($update['reverse_paths']) : [];
    }

    // Determine updates to be performed.
    foreach ($updates as $function => $update) {
      if ($update['allowed']) {
        // Set the installed version of each module so updates will start at the
        // correct place. (The updates are already sorted, so we can simply base
        // this on the first one we come across in the above foreach loop.)
        if (isset($start[$update['module']])) {
          \Drupal::service('update.update_hook_registry')->setInstalledVersion($update['module'], $update['number'] - 1);
          unset($start[$update['module']]);
        }
        $batch_builder->addOperation('update_do_one', [$update['module'], $update['number'], $dependency_map[$function]]);
      }
    }

    $post_updates = $this->postUpdateRegistry->getPendingUpdateFunctions();

    if ($post_updates) {
      // Now we rebuild all caches and after that execute the hook_post_update()
      // functions.
      $batch_builder->addOperation('drupal_flush_all_caches', []);
      foreach ($post_updates as $function) {
        $batch_builder->addOperation('update_invoke_post_update', [$function]);
      }
    }

    batch_set($batch_builder->toArray());

    // @todo Revisit once https://www.drupal.org/node/2548095 is in.
    return batch_process(Url::fromUri('base://results'), Url::fromUri('base://start'));
  }

  /**
   * Finishes the update process and stores the results for eventual display.
   *
   * After the updates run, all caches are flushed. The update results are
   * stored into the session (for example, to be displayed on the update results
   * page in update.php). Additionally, if the site was off-line, now that the
   * update process is completed, the site is set back online.
   *
   * @param bool $success
   *   Indicate that the batch API tasks were all completed successfully.
   * @param array $results
   *   An array of all the results that were updated in update_do_one().
   * @param array $operations
   *   A list of all the operations that had not been completed by the batch
   *   API.
   */
  public static function batchFinished($success, $results, $operations) {
    // No updates to run, so caches won't get flushed later.  Clear them now.
    drupal_flush_all_caches();

    $session = \Drupal::request()->getSession();
    $session->set('update_results', $results);
    $session->set('update_success', $success);
    $session->set('updates_remaining', $operations);

    // Now that the update is done, we can put the site back online if it was
    // previously not in maintenance mode.
    if (!$session->remove('maintenance_mode')) {
      \Drupal::state()->set('system.maintenance_mode', FALSE);
    }
  }

  /**
   * Provides links to the homepage and administration pages.
   *
   * @param \Symfony\Component\HttpFoundation\Request $request
   *   The current request.
   *
   * @return array
   *   An array of links.
   */
  protected function helpfulLinks(Request $request) {
    // @todo Simplify with https://www.drupal.org/node/2548095
    $base_url = str_replace('/update.php', '', $request->getBaseUrl());
    $links['front'] = [
      'title' => $this->t('Front page'),
      'url' => Url::fromRoute('<front>')->setOption('base_url', $base_url),
    ];
    if ($this->account->hasPermission('access administration pages')) {
      $links['admin-pages'] = [
        'title' => $this->t('Administration pages'),
        'url' => Url::fromRoute('system.admin')->setOption('base_url', $base_url),
      ];
    }
    if ($this->account->hasPermission('administer site configuration')) {
      $links['status-report'] = [
        'title' => $this->t('Status report'),
        'url' => Url::fromRoute('system.status')->setOption('base_url', $base_url),
      ];
    }
    return $links;
  }

  /**
   * Retrieves module updates.
   *
   * @return array
   *   The module updates that can be performed.
   */
  protected function getModuleUpdates() {
    $return = [];
    $updates = update_get_update_list();
    foreach ($updates as $module => $update) {
      $return[$module] = $update['start'];
    }

    return $return;
  }

}