Computed field module: value of field when creating new content

Question

for my content type I have this computed field code and when I update existing node everything is ok, but when I create new node, menu_get_object return empty values and drupal display this error message "EntityMalformedException: Missing bundle property on entity of type node. in entity_extract_ids() (line 7562 of /var/www/dev/testpage/includes/common.inc)." and nothing was saved. When I used dpm() in devel it show me that after creating new content $node is empty, but when I update node created before everything is OK.

$node = menu_get_object();
$start_time = field_get_items('node', $node, 'field_start_time');
$start_time = $start_time[0]['value'];
$entity_field[0]['value'] = '$start_time';

thanks a lot for your reply

Answer 1

menu_get_object() provides access to objects loaded by the current router item. For example, on the page node/%node, the router loads the %node object, and calling menu_get_object() will return that.

From: http://api.drupal.org/api/drupal/includes!menu.inc/function/menu_get_object/7

It returns empty upon creation because you add the node from "node/add/[content-type]" page but update it from "node/[nid]" and it can use the nid to load the node.

If you need just to duplicate the value from the start_time field of the same node, use this:

$entity_field[0]['value'] = $entity->field_start_time[0]['value'];