Woocommerce change tax rate on coupon use

Question

I'm trying to update my Woocommerce tax rate when a certain coupon is used. For this I'm using this code in my functions.php:

function apply_matched_coupons() {
global $woocommerce;

$coupon_code = '123456'; 

if ( $woocommerce->cart->has_discount( $coupon_code ) ) {

$tax_class = 'Reduced rate';
}
return $tax_class;
}
add_action( 'woocommerce_product_tax_class','apply_matched_coupons' );

This works perfectly on the frontend, HOWEVER after I put this code in my child theme functions.php I'm getting the following error in the backend when I open the "Products" page in wp-admin:

Fatal error: Call to a member function has_discount() on a non-object in xxxx/xxxx/xxxxx/xxxx/functions.php on line 57

Now I suddenly can't seem to get a list of my products in the backend. The loading of the products is broken after the first product's price.

Any idea how I should modify this code so both the frontend and backend works like it should? I'm a noob at coding so sorry if this is a stupid question!

I searched Google and Stackoverflow and came up with similar code that worked on the frontend but always gave the same error on the backend.

Thanks for the help!

Reigel Reigel · Accepted Answer · 2017-05-12T07:04:10

well, first let's tweak your code a bit.

You don't need global $woocommerce; use WC() in place of $woocommerce. And let's add !is_admin() on your if. So it should just work on the frontend.

function apply_matched_coupons() {

    $coupon_code = '123456'; 

    if ( !is_admin() && WC()->cart->has_discount( $coupon_code ) ) {
        $tax_class = 'Reduced rate';
    }
    return $tax_class;
}
add_action( 'woocommerce_product_tax_class','apply_matched_coupons' );

Woocommerce change tax rate on coupon use

1 Answers