Issue #3167733 by Spokje, vishnukumar, bkosborne, surya.s, kndr, alexpott: PHP...

        $widget = $display->getComponent($field_name);

        // We define "tag-like" taxonomy fields as ones that use the

        // "Autocomplete (Tags style)" widget.

        if ($widget['type'] == 'entity_reference_autocomplete_tags') {

        if (!empty($widget) && $widget['type'] == 'entity_reference_autocomplete_tags') {

          $tag_fields[$field_name] = $field;

        }

      }

<?php

namespace Drupal\Tests\node\Functional\Views\Wizard;

use Drupal\Core\Field\FieldStorageDefinitionInterface;

use Drupal\field\Entity\FieldConfig;

use Drupal\field\Entity\FieldStorageConfig;

use Drupal\Tests\views\Functional\Wizard\WizardTestBase;

/**

 * Tests node wizard and content type with hidden Taxonomy Term Reference field.

 *

 * @group Views

 * @group node

 */

class HiddenTaxonomyTermReferenceFieldWizardTest extends WizardTestBase {

  /**

   * {@inheritdoc}

   */

  protected $defaultTheme = 'stark';

  /**

   * Modules to enable.

   *

   * @var array

   */

  protected static $modules = ['taxonomy'];

  /**

   * Tests content type with a hidden Taxonomy Term Reference field.

   */

  public function testHiddenTaxonomyTermReferenceField() {

    // Create Article node type.

    $this->drupalCreateContentType(['type' => 'article', 'name' => 'Article']);

    // Create a taxonomy_term_reference field on the article Content Type. By

    // not assigning a widget to that field we make sure it is hidden on the

    // Form Display.

    $this->fieldName = mb_strtolower($this->randomMachineName());

    FieldStorageConfig::create([

      'field_name' => $this->fieldName,

      'entity_type' => 'node',

      'type' => 'entity_reference',

      'cardinality' => FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED,

      'settings' => [

        'target_type' => 'taxonomy_term',

      ],

    ])->save();

    FieldConfig::create([

      'field_name' => $this->fieldName,

      'bundle' => 'article',

      'entity_type' => 'node',

      'settings' => [

        'handler' => 'default',

      ],

    ])->save();

    $this->drupalGet('admin/structure/views/add');

    $this->assertSession()->statusCodeEquals(200);

  }

}

<?php

namespace Drupal\Tests\node\Functional\Views;

namespace Drupal\Tests\node\Functional\Views\Wizard;

use Drupal\Tests\views\Functional\Wizard\WizardTestBase;

use Drupal\views\Views;