Hide variation info from cart item title in WooCommerce 3+

This filter should work returning a false value for $should_include_attributes first argument in woocommerce_product_variation_title_include_attributes filter hook this way:

add_filter( 'woocommerce_product_variation_title_include_attributes', 'custom_product_variation_title', 10, 2 );
function custom_product_variation_title($should_include_attributes, $product){
    $should_include_attributes = false;
    return $should_include_attributes;
}

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

It should just work as you expect.

Update: The shorter way is:

add_filter( 'woocommerce_product_variation_title_include_attributes', '__return_false' );

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

just works too.

Update: Prices are also cached in transient wp_options table.

Let say your product ID is 222, you will have that transients meta_keys in wp_options table (for this product ID):

'_transient_timeout_wc_product_children_22'
'_transient_wc_product_children_22'
'_transient_timeout_wc_var_prices_222' // <=== <=== HERE
'_transient_wc_var_prices_222'    // <=== <=== <=== HERE

What you can try to do is to update expiration date meta_value to an outdated timestamp, this way:

// Set here your product ID
$main_product_id = 222
$transcient_product_meta_key = '_transient_wc_var_prices_'. $main_product_id;
update_option( $transcient_product_meta_key, strtotime("-12 hours") );
wp_cache_delete ( 'alloptions', 'options' ); // Refresh caches

This way you will force the system to rebuild this outdated cached transient.

Additionally you should try to add/update in your parent product ID (the main product where variation are set) these:

// Set here your Main product ID (for example the last variation ID of your product)
$post_id = 22;

// Set here your variation ID (for example the last variation ID of your product)
$variation_id = 24;

// Here your Regular price
$reg_price = 100;
// Here your Sale price
$sale_price = 50;

update_post_meta($post_id, '_min_variation_price', $sale_price);
update_post_meta($post_id, '_max_variation_price', $sale_price);
update_post_meta($post_id, '_min_variation_regular_price', $reg_price);
update_post_meta($post_id, '_max_variation_regular_price', $reg_price);
update_post_meta($post_id, '_min_variation_sale_price', $sale_price);
update_post_meta($post_id, '_max_variation_sale_price', $sale_price); 

update_post_meta($post_id, '_min_price_variation_id', $variation_id);
update_post_meta($post_id, '_max_price_variation_id', $variation_id);
update_post_meta($post_id, '_min_regular_price_variation_id', $variation_id);
update_post_meta($post_id, '_max_regular_price_variation_id', $variation_id);
update_post_meta($post_id, '_min_sale_price_variation_id', $variation_id);
update_post_meta($post_id, '_max_sale_price_variation_id', $variation_id);

// Optionally
wc_delete_product_transients($variation_id);

Update 2021 (Handling mini cart custom item price)

With WooCommerce version 3.0+ you need:

• To use woocommerce_before_calculate_totals hook instead.
• To use WC_Cart get_cart() method instead
• To use WC_product set_price() method instead

Here is the code:

// Set custom cart item price
add_action( 'woocommerce_before_calculate_totals', 'add_custom_price', 1000, 1);
function add_custom_price( $cart ) {
    // This is necessary for WC 3.0+
    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    // Avoiding hook repetition (when using price calculations for example | optional)
    if ( did_action( 'woocommerce_before_calculate_totals' ) >= 2 )
        return;

    // Loop through cart items
    foreach ( $cart->get_cart() as $cart_item ) {
        $cart_item['data']->set_price( 40 );
    }
}

And for mini cart (update):

// Mini cart: Display custom price 
add_filter( 'woocommerce_cart_item_price', 'filter_cart_item_price', 10, 3 );
function filter_cart_item_price( $price_html, $cart_item, $cart_item_key ) {

    if( isset( $cart_item['custom_price'] ) ) {
        $args = array( 'price' => 40 );

        if ( WC()->cart->display_prices_including_tax() ) {
            $product_price = wc_get_price_including_tax( $cart_item['data'], $args );
        } else {
            $product_price = wc_get_price_excluding_tax( $cart_item['data'], $args );
        }
        return wc_price( $product_price );
    }
    return $price_html;
}

Code goes in functions.php file of your active child theme (or active theme).

This code is tested and works (still works on WooCommerce 5.1.x).

Note: you can increase the hook priority from 20 to 1000 (or even 2000) when using some few specific plugins or others customizations.

Related:

• Set cart item price from a hidden input field custom price in Woocommerce 3
• Change cart item prices based on custom cart item data in Woocommerce
• Set a specific product price conditionally on Woocommerce single product page & cart
• Add a select field that will change price in Woocommerce simple products