Product variation and parent variable product objects in WooCommerce hook

I developed a custom delivery time info for variations. But for some reason, I can’t get the parent product id of the variation to use it in my function. I tried the following – if I set $id straight to 51237, my code works, but with using $post to get the id, it doesn’t. Any help appreciated!

// here I am loading special infos for each variation

add_filter( 'woocommerce_available_variation', 'load_variation_products_fields', 1 );
function load_variation_products_fields( $variations ) {
    $variations['variation_cmpzDeliveryTime'] = get_delivery_time( $variations[ 'variation_id' ] ) ;
    return $variations;
}


function get_delivery_time ( $product_id) {
    $product_obj = wc_get_product( $product_id );
    

    // here I want the post ID (so the parent product ID if the product type is variation)
    global $post;
    $id = $post->ID; 

    var_dump ($id); // this outputs "int(51237)" for each variation - that seems to be right!

    switch($product_obj->get_type())    {
        case 'variation':
            if (Helpers::get_product_multi_inventory_status($product_id) == 'no' ) {
                $_pf = new WC_Product_Factory(); 
                $_product = $_pf->get_product($product_id);
                $stock_status = $_product->get_stock_status();
                if ( wc_gzd_get_product( $product_id )->get_delivery_time_html() == '' )    { 
                    if ( ($stock_status == 'instock')   )   {
                        // $id is ignored - if I put here 51237, it works!
                        return set_delivery_text('instock', $id); 
                    } else  {
                        return set_delivery_text('outofstock');
                    }
                }
            }
            elseif (Helpers::get_product_multi_inventory_status($product_id) == 'yes' ) {
                return get_delivery_time_multi_inventory($product_id);
            }
            break;
    }
}

Answer

There are some missing arguments in your function hooked in woocommerce_available_variation… You need to replace it by:

// here I am loading special infos for each variation
add_filter( 'woocommerce_available_variation', 'load_variation_products_fields', 10, 3 );
function load_variation_products_fields( $variation_data, $product, $variation ) {
    $variation_data['variation_cmpzDeliveryTime'] = get_delivery_time( $variation_data, $product, $variation ) ;
    return $variation_data;
}

Now as you can see there is 3 arguments, where $product is the parent variable product object and $variation is the product variation Object.

So you will change you will also have to change get_delivery_time() function code something like:

function get_delivery_time ( $variation_data, $product, $variation ) {
    $variation_id      = $variations['variation_id']; // or $variation->get_id();
    $is_in_stock       = $variation['is_in_stock']; // is variation "in stock"
    $parent_product_id = $product->get_id(); // The parent variable product Id
    // var_dump($parent_product_id);

    if ( Helpers::get_product_multi_inventory_status($variation_id) == 'no' ) { 
        if ( wc_gzd_get_product( $variation_id )->get_delivery_time_html() == '' )    { 
            if ( $is_in_stock ) {
                return set_delivery_text('instock', $parent_product_id); 
            } else  {
                return set_delivery_text('outofstock');
            }
        }
    } else {
        return get_delivery_time_multi_inventory($variation_id);
    }
}

it should work better.