Hi again,
After searching further, I found the process_front_end_tickets_form function in event-tickets-plus/src/Tribe/Commerce/WooCommerce/Main.php. Since I didn’t find any hook in there, I attached my function to the same wp_loaded action, but with an earlier priority. It seems to be working fine.
add_action( 'wp_loaded', 'clear_cart_after_submitting_ticket_form', 10 );
function clear_cart_after_submitting_ticket_form() {
global $woocommerce;
if ( empty( $_REQUEST['wootickets_process'] ) || intval( $_REQUEST['wootickets_process'] ) !== 1 || empty( $_POST['product_id'] ) ) {
return;
}
$woocommerce->cart->empty_cart();
}