Error when adding product with custom pricing to cart - WooCommerce

Question

I have set up a custom user role with a slug of performance_customer. I am checking to see if the current user is a "performance customer" and apply certain price discounts to products in specific categories.

Here is my code:

function return_custom_performance_dealer_price($price, $product) {

    global $woocommerce;
    global $post;
    $terms = wp_get_post_terms( $post->ID, 'product_cat' );
    foreach ( $terms as $term ) $categories[] = $term->slug;

    $origPrice = get_post_meta( get_the_ID(), '_regular_price', true);
    $price = $origPrice;

    //check if user role is performance dealer
    $current_user = wp_get_current_user();
    if( in_array('performance_customer', $current_user->roles)){
        //if is category performance hard parts
        if(in_array( 'new-hard-parts-150', $categories )){
            $price = $origPrice * .85;
        }
        //if is category performance clutches
        elseif(in_array( 'performance-clutches-and-clutch-packs-150', $categories )){
            $price = $origPrice * .75;
        }
        //if is any other category
        else{
            $price = $origPrice * .9;
        }
    }
    return $price;
}
add_filter('woocommerce_get_price', 'return_custom_performance_dealer_price', 10, 2);

The function works perfectly in the product loop, but when I added a product to the cart it blew up and gave me this error for each line containing if(in_array( 'CATEGORY_NAME_HERE', $categories )){.

Error: Warning: in_array() expects parameter 2 to be array, null given in…

I'm guessing this has to do with the 5th line of the code above where I use wp_get_post_terms() to form an array of the categories that each product belongs to. I'm not sure how to make this work.

Answer 1

First, the filter hook woocommerce_product_get_price is now replacing deprecated hook woocommerce_get_price…

To avoid the error you got you should use Wordpress conditional dedicated function has_term()

I have revisited your code a bit, so please try this instead:

add_filter('woocommerce_product_get_price', 'return_custom_performance_dealer_price', 10, 2);
function return_custom_performance_dealer_price( $price, $product ) {

    $price = $product->get_regular_price();

    //check if user role is performance dealer
    $current_user = wp_get_current_user();
    if( in_array('performance_customer', $current_user->roles) ){

        //if is category performance hard parts
        if( has_term( 'new-hard-parts-150', 'product_cat', $product->get_id() ) ){
            $price *= .85;
        }
        //if is category performance clutches
        elseif( has_term( 'performance-clutches-and-clutch-packs-150', 'product_cat', $product->get_id() ) ){
            $price *= .75;
        }
        //if is any other category
        else{
            $price *= .9;
        }
    }
    return $price;
}

Code goes in function.php file of your active child theme (or theme) or also in any plugin file.

Tested for WooCommerce 3+… It should work now…