How to override node comment form template?

Question

I usually override a form template this way.

/**
 * Implementation of hook_theme().
 */
function MODULE_theme() {
  return array(
    'user_login' => array(
      'render element' => 'form',
      'template' => 'user_login',
      'path' => drupal_get_path('module', 'MODULE').'/templates',
    ),
  );
}

I create templates/user_login.tpl.php in my module folder; then, I can override the form.

I tried overriding a node comment form this way, but it didn't work: The node comment form didn't use my custom template file.

I have googled a lot, but I got nothing about overriding a node comment form template.

How can I force Drupal to use a template file for the node comment form?

Answer 1

In Drupal 7, and in the case of the user login form, your trick works because the form doesn't set the #theme property; in that case, Drupal will use the theme function whose machine name is equal to the form ID. (For the login for, that is user_login.)
That is not true for the comment form, for which its form build (comment_form()) sets the #theme property.

$form['#theme'] = array('comment_form__node_' . $node->type, 'comment_form');

There isn't a match between the machine name of the theme the form builder wants to use, and the comment-edit form ID; the latter is comment_node_CONTENT_TYPE_form, not comment_form__node_CONTENT_TYPE. If you were defining a comment_form theme function, that should work.

In Drupal 6, there is no #theme property for comment_form, which is the form ID of the comment edit form.

Answer 2

Following code will allow you to use comment-form--node-forum.tpl.php template:

/**
 * Implements hook_theme().
 */
function hook_theme($existing, $type, $theme, $path) {
  return array(
    "comment_form__node_forum" => array(
      'render element' => 'form',
      'template' => "comment-form--node-forum"
    )
  );
}

Replace 'forum' to your content type.