Only show the WooCommerce Barcode on processing (and completed) orders

custom_prevent_barcode.php

<?php

//Add this to your (child-)theme functions.php file

//Before woocommerce_email_after_order_table 1 and woocommerce_order_details_after_order_table 1, because on the woocommerce_order_barcodes_display_barcode filter we don't have access to the $order object
add_action( 'woocommerce_email_after_order_table', 'custom_prevent_barcode', -1, 1 );
add_action( 'woocommerce_order_details_after_order_table', 'custom_prevent_barcode', -1, 1 );
function custom_prevent_barcode( $order ) {
	$allowed_statuses = array(
		'processing',
		//'completed', //Uncomment this if you also want the barcode if the order is completed
	);
	//Status not allowed? Return false to the woocommerce_order_barcodes_display_barcode filter
	if ( ! $order->has_status( $allowed_statuses ) ) {
		add_filter( 'woocommerce_order_barcodes_display_barcode', '__return_false' );
	}
}