gistfile1.php

<?php

add_filter( 'woocommerce_payment_complete_order_status', 'subscription_order_payment_onhold_order_status', 10, 2 );

/**
 * Catch new subscription orders, and put the order on-hold by default.
 */
function subscription_order_payment_onhold_order_status( $order_status, $order_id ) {
	$order = new WC_Order( $order_id );
	if ( 'processing' != $order_status || ( 'on-hold' != $order->status && 'pending' != $order->status && 'failed' != $order->status ) )
		return $order_status;
	 
	$subscription_order = false;
	
	// If for some reason there are no items in the order, bail.
	if ( empty( $order->get_items() ) )
		return $order_status;
	
	foreach( $order->get_items() as $item ) {
		if ( 'line_item' != $item['type'] )
			continue;
		$_product = $order->get_product_from_item( $item );
		if ( $_product->is_subscription() ) {
			// once we've found one subscription product we know we're done, break out of the loop
			return 'on-hold';
			break;
		}
	}

	// non-subscription order, return original status
	return $order_status;
}