Allow admin users to be reminded when forms in /admin are likely to alter configuration

Adding link to Config Override Warn as inspiration

Adding an option for the warning to include a custom message.

Playing around with this a little and the following working “pseudo code” (i.e. please don’t actually use this as is - it is just to test ideas) gives the idea of what I’m thinking:

function xx_form_alter(&$form, FormStateInterface $form_state, $form_id) :void {

  // Get out of here if it is not an admin form.
  if (!\Drupal::service('router.admin_context')->isAdminRoute()) {
    return;
  }

  // We need an actual object rather than just a jumble of array items.
  $form_object = $form_state->getFormObject();

  // Assume forms have no config to begin with.
  $has_config = FALSE;

  // Does the getEditableConfigNames method exist on the form?
  if (method_exists($form_object, 'getEditableConfigNames')) {
    $has_config = TRUE;
  }

  // Are we editing an entity that has config form for it's setup?
  if ($form_object instanceof EntityForm) {
    $entity = $form_object->getEntity();
    if ($entity instanceof ConfigEntityInterface && !$entity->isNew()) {
      $has_config = TRUE;
    }
  }

  // Permisions being permissions.
  if ($form_object instanceof UserPermissionsForm) {
    $has_config = TRUE;
  }

  // Blocks being blocks.
  if ($form_object instanceof BlockListBuilder) {
    $has_config = TRUE;
  }
  // Okay, warn people.
  if ($has_config) {
    \Drupal::service('messenger')->addWarning(t("This form is likely to alter the running configuration of the site and, therefore, changes should probably go through the development quality processes."));
  }

}

Note: BlockListBuilder extends ConfigEntityListBuilder and that ’s probably worth looking out for, rather than the special case of blocks.

Isn't this the same as 🐛 Display status message on configuration forms when there are overridden values Fixed ?

Actually, reading again, it's not the same, sorry!