PHP Notice: Undefined index: content in template_preprocess_node()

Notice: Undefined index: content in template_preprocess_node() (line 1467 of drupal-7.x-dev\modules\node\node.module).

function template_preprocess_node(&$variables) {
...
  // Helpful $content variable for templates.
  foreach (element_children($variables['elements']) as $key) {
    $variables['content'][$key] = $variables['elements'][$key];
  }

  // Make the field variables available with the appropriate language.
  field_attach_preprocess('node', $node, $variables['content'], $variables); //<--line 1467

the content could be empty if links are removed with views module, body is empty and comment module disabled..

solution: add $variables['content'] = array(); before foreach..