Error when trying to view revisions

Question

Using Drupal 8/9. When trying to view previous revisions I am getting the following error:

Error: Call to a member function getType() on string in clc_d8_theme_theme_suggestions_page_alter() (line 13 of /var/www/html/wrc/web/themes/clc_d8_theme/clc_d8_theme.theme)

It refers to this code:

function clc_d8_theme_theme_suggestions_page_alter(array &$suggestions, array $variables) {
  // Add content type suggestions.
  if ($node = \Drupal::request()->attributes->get('node')) {
    array_splice($suggestions, 1, 0, 'page__node__' . $node->getType()); <-- error at this line
  }
}

I need the type suggestions for my theme. How do I fix this? I thought the check on the node would be enough to avoid issues.

Answer 1

"$node" can vary a bit by context, but here are some ways to set $node:

$routeName = \Drupal::routeMatch()->getRouteName();

$node = NULL;

// $variables['node'].
if (isset($variables['node'])) {
  $node = $variables['node'];
  if (is_numeric($variables['node'])) {
    $node = \Drupal::entityTypeManager()->getStorage('node')->load($variables['node']);
  }
}

// $variables['row'].
if (isset($variables['row']) && !empty($variables['row']->nid)) {
  $node = \Drupal::entityTypeManager()->getStorage('node')->load($variables['row']->nid);
}

// $routeName === 'entity.node.canonical'.
if ($routeName === 'entity.node.canonical') {
  $node = \Drupal::routeMatch()->getParameter('node');
}

// $routeName === 'entity.node.revision'.
if ($routeName === 'entity.node.revision') {
  $revisionId = \Drupal::routeMatch()->getParameter('node_revision')->getRevisionId();
  $node = node_revision_load($revisionId);
}

// $routeName === 'entity.node.preview'.
if ($routeName === 'entity.node.preview') {
  $node = \Drupal::routeMatch()->getParameter('node_preview');
}

if ($node) {
  // run your code...
}

Specifically, it looks like you're after:

// Get route name.
$routeName = \Drupal::routeMatch()->getRouteName();

// Check if route is node revision.
if ($routeName === 'entity.node.revision') {
  $revisionId = \Drupal::routeMatch()->getParameter('node_revision')->getRevisionId();
  $node = node_revision_load($revisionId);
}

This will fully load your node object and ->getType() should work without error.