+<?php
+
+namespace Drupal\inline_form_errors;
+
+use Drupal\Core\Form\FormElementHelper;
+use Drupal\Core\Form\FormErrorHandler as CoreFormErrorHandler;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Render\Element;
+use Drupal\Core\Routing\LinkGeneratorTrait;
+use Drupal\Core\Render\RendererInterface;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
+use Drupal\Core\StringTranslation\TranslationInterface;
+use Drupal\Core\Url;
+use Drupal\Core\Utility\LinkGeneratorInterface;
+
+/**
+ * Produces inline form errors.
+ */
+class FormErrorHandler extends CoreFormErrorHandler {
+
+ use StringTranslationTrait;
+ use LinkGeneratorTrait;
+
+ /**
+ * The renderer service.
+ *
+ * @var \Drupal\Core\Render\RendererInterface
+ */
+ protected $renderer;
+
+ /**
+ * Constructs a new FormErrorHandler.
+ *
+ * @param \Drupal\Core\StringTranslation\TranslationInterface $string_translation
+ * The string translation service.
+ * @param \Drupal\Core\Utility\LinkGeneratorInterface $link_generator
+ * The link generation service.
+ * @param \Drupal\Core\Render\RendererInterface $renderer
+ * The renderer service.
+ */
+ public function __construct(TranslationInterface $string_translation, LinkGeneratorInterface $link_generator, RendererInterface $renderer) {
+ $this->stringTranslation = $string_translation;
+ $this->linkGenerator = $link_generator;
+ $this->renderer = $renderer;
+ }
+
+ /**
+ * Loops through and displays all form errors.
+ *
+ * @param array $form
+ * An associative array containing the structure of the form.
+ * @param \Drupal\Core\Form\FormStateInterface $form_state
+ * The current state of the form.
+ */
+ protected function displayErrorMessages(array $form, FormStateInterface $form_state) {
+ // Use the original error display for Quick Edit forms, because in this case
+ // the errors are already near the form element.
+ if ($form['#form_id'] === 'quickedit_field_form') {
+ parent::displayErrorMessages($form, $form_state);
+ return;
+ }
+
+ $error_links = [];
+ $errors = $form_state->getErrors();
+ // Loop through all form errors and check if we need to display a link.
+ foreach ($errors as $name => $error) {
+ $form_element = FormElementHelper::getElementByName($name, $form);
+ $title = FormElementHelper::getElementTitle($form_element);
+
+ // Only show links to erroneous elements that are visible.
+ $is_visible_element = Element::isVisibleElement($form_element);
+ // Only show links for elements that have a title themselves or have
+ // children with a title.
+ $has_title = !empty($title);
+ // Only show links for elements with an ID.
+ $has_id = !empty($form_element['#id']);
+
+ // Do not show links to elements with suppressed messages. Most often
+ // their parent element is used for inline errors.
+ if (!empty($form_element['#error_no_message'])) {
+ unset($errors[$name]);
+ }
+ elseif ($is_visible_element && $has_title && $has_id) {
+ $error_links[] = $this->l($title, Url::fromRoute('<none>', [], ['fragment' => $form_element['#id'], 'external' => TRUE]));
+ unset($errors[$name]);
+ }
+ }
+
+ // Set normal error messages for all remaining errors.
+ foreach ($errors as $error) {
+ $this->drupalSetMessage($error, 'error');
+ }
+
+ if (!empty($error_links)) {
+ $render_array = [
+ [
+ '#markup' => $this->formatPlural(count($error_links), '1 error has been found: ', '@count errors have been found: '),
+ ],
+ [
+ '#theme' => 'item_list',
+ '#items' => $error_links,
+ '#context' => ['list_style' => 'comma-list'],
+ ],
+ ];
+ $message = $this->renderer->renderPlain($render_array);
+ $this->drupalSetMessage($message, 'error');
+ }
+ }
+
+}