From investigation of WT-14542, a bug has been encountered when fetching a dhandle using session_get_dhandle. After __session_get_dhandle, we need to check if we want to lock the dhandle using __wt_session_lock_dhandle. In this case we can return early and leave the dhandle in an incomplete state, here is the code:

        /*
         * If the handle is already open for a special operation, give up.
         */
        if (btree != NULL && F_ISSET(btree, WT_BTREE_SPECIAL_FLAGS))
            return (__wt_set_return(session, EBUSY));

In this case, if the handle has the WT_BTREE_SPECIAL_FLAGS set, we return back EBUSY but never set session->dhandle to NULL. Users are still allowed to access this dhandle and potentially create a race condition when not allowed.