Adding Module Config Form Leads to WSOD

Question

I am trying to create a configuration form for my test Drupal 8 module. I have followed the instructions from the following tutorials:

https://www.drupal.org/docs/8/api/configuration-api/working-with-configuration-forms https://www.drupal.org/docs/8/api/form-api/configformbase-with-simple-configuration-api

Before I followed the instructions in these guides my module worked fine. However, after adding the form, I now get a WSOD when installing the module, with no error in the logs. I know that error reporting is on because I can make intentional mistakes in my module files and an error will be reported in the logs.

My question is: where have I gone wrong? It's hard to figure out a problem when you don't even have a stack trace to follow.

My company_info.routing.yml file:

company_info.content:
  path: '/company_info'
  defaults:
    _controller: '\Drupal\company_info\Controller\AdminController::content'
    _title: 'Hello World'
  requirements:
    _permission: 'access content'

company_info.admin_settings:
  path: '/admin/config/company_info'
  defaults:
    _form: '\Drupal\company_info\Form\AdminSettingsForm'
    _title: 'example'
  requirements:
    _permission: 'administer site configuration'

AdminSettingsForm.php:

<?php

namespace Drupal\company_info\Controller;

use Drupal\Core\Form\ConfigFormBase;
use Symfony\Component\HttpFoundation\Request;
use Drupal\Core\Form\FormStateInterface;

class AdminSettingsForm extends ConfigFormBase {

  /**
   * {@inheritdoc}
   */
  public function getFormId() {
    return 'company_info_admin_settings';
  }

  /**
   * {@inheritdoc}
   */
  public function getEditableConfigNames() {
    return [
      'company_info.settings',
    ];
  }

  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state, 
Request $request = NULL) {
    $config = $this->config('company_info.settings');

    $form['your_message'] = array(
      '#type' => 'textfield',
      '#title' => $this->t('Your Message!'),
      '#default_value' => $config->get('your_message'),
    );

    return parent::buildForm($form, $form_state);
  }

  /**
   *
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {
    $this->config('company_info.settings')
      ->set('your_message', $form_state->getValues('your_message'))
      ->save();

  }
}

company_info.settings.yml

your_message: 'Default message here'

Answer 1

The namespace on your AdminSettingsForm class is incorrect.
It should be Drupal\company_info\Form;