save_post hook not triggered in WP v3.6.1

Question

I developed a plugin having a custom metabox that is using the save_post hook to store data. The plugin is 18 months old and is used by thousands of customers, so I'm pretty sure everything is good.

Since I updated my testing platform to v3.6.1, I can't get that hook to run on previously created pages/posts. It only works on new ones.

(I am the only WP user in the website. WP DEBUG is enabled)

Has anyone experienced the same? Any clue? I missed some changes?

EDIT:

The code I'm using now to check the hook is this (I've deleted the inner code for privacy reasons):

function saving_metabox($post_id) {
    die('test');

    if(isset($_POST['plugin_noncename'])) {
               ... ...
    }

    return $post_id;
}
add_action('save_post', 'saving_metabox');

Answer 1

Try changing your content and saving again. This will trigger the action. save_post is only called if the content has changed.

To come in before this is checked, you can use the pre_post_update hook.

add_action( 'pre_post_update', 'saving_metabox' );
function saving_metabox( $post_id ) {
    die('test');
}