BaseFormIdInterface.php

<?php

namespace Drupal\Core\Form;


/**
 * Provides an interface for a Form that has a base form ID.
 *
 * This will become the $form_state->getBuildInfo()['base_form_id'] used to
 * generate the name of hook_form_BASE_FORM_ID_alter().
 */
interface BaseFormIdInterface extends FormInterface {
    
    /**
     * Returns a string identifying the base form.
     *
     * @return string|null
     *   The string identifying the base form or NULL if this is not a base form.
     */
    public function getBaseFormId();

}