Ticket #20564: 20564-new-action.2.diff

src/wp-admin/includes/post.php

@@ -1529 +1529 @@
                 $new_autosave['ID'] = $old_autosave->ID;
                 $new_autosave['post_author'] = $post_author;
 
+                do_action( '_wp_creating_autosave', $new_autosave );
+
                 // If the new autosave has the same content as the post, delete the autosave.
                 $post = get_post( $post_id );
                 $autosave_is_different = false;