_fullcalendar_update_access() expects entity (object), receives entity id (string) as menu access callback

I think I have this same error. A user with permission to edit own content can drag-and-drop in the calendar, but the item isn't saved. (Rather, the drag-and-drop is treated as a click, and the user is redirected to the item page.)

I'm using this on nodes, and the log says message fullcalendar/ajax/update/drop/438 (where 438 is the NID).

I tried adding this to _fullcalendar_update_access($entity), but with no result:
return entity_access('update', $entity->entity_type, $entity);

Maybe the bug is somewhere else, and the _fullcalendar_update_access($entity) is actually returning the proper access.

The 'fullcalendar/ajax/update/%/%' menu callback uses this function as an access callback but passes it a numerical id instead of an entity object.

Additionally the 'bundle' property is not present on all entities, nodes for example - they use $entity->type. The fullcalendar module prepares entity objects with a 'bundle' property when this function is called elsewhere.

I think we should be using node_load/user_load here to load the object when required and check content (node) and user permissions for now.

Ideally we could call entity_load/entity_access and be done with it but without entity being a dependency of fullcalendar this wont work. Or should we say that entity is the new views and sites that do not have it are the edge case?

I suppose that a lot of refactoring should be done here so we can know what entity is being updated.
For now a workaround is to implement a custom module to alter the menu and populate an entity object in the access callback.
It wouldn't work on other entities though.
Also you can use the api function hook_fullcalendar_editable()

/**
 * Implements hook_menu_alter().
 */
function MY_MODULE_menu_alter(&$items) {
    $items['fullcalendar/ajax/update/%/%']['access callback'] = '_MY_MODULE_update_access';
}

function _MY_MODULE_update_access($entity_id) {
    //For now load the node entity :( and pass it to _fullcalendar_update_access
    $entity = entity_load_single('node', $entity_id);
    if (is_object($entity)) {
        $entity->bundle = $entity->type;
    }
    return _fullcalendar_update_access($entity);
}

The attached patch fixes the problem by reading entity_type from $_POST (as also done in the page callback fullcalendar_update()). I also replaced the node-specific access check with entity_access(), adding a dependency on the entity module.