No decrement on order wordpress - wordpress

Question

everybody !
I'm looking for a way to no decrement when an order is completed.
Exemple: I got 1 T-shirt with 20 quantity. When i order, i want the number to be still 20, and not 19.)
here my hook:
add_action( 'woocommerce_order_status_completed', 'action_on_order_completed' , 10, 1 );
function action_on_order_completed( $order_id )
{
// Get an instance of the order object
$order = wc_get_order( $order_id );
// Iterating though each order items
foreach ( $order->get_items() as $item_id => $item_values ) {
// Item quantity
$item_qty = $item_values['qty'];
// getting the product ID (Simple and variable products)
$product_id = $item_values['variation_id'];
if( $product_id == 0 || empty($product_id) ) $product_id = $item_values['product_id'];
// Get an instance of the product object
$product = wc_get_product( $product_id );
// Get the stock quantity of the product
$product_stock = $product->get_stock_quantity();
// Increase back the stock quantity
wc_update_product_stock( $product, $item_qty, 'increase' );
}
}
But when the order is completed, the quantity still decrease. Any idea ?

Answer 1

That is because your hooked function is triggered after stock quantity is decreased.
You are trying to get previous stock quantity with
$product_stock = $product->get_stock_quantity();
But in that case this method returns already decreased value.
So, try this:
wc_update_product_stock( $product, $product_stock + $item_qty, 'increase' );