Woocommerce Is_Purchasable cause ajax error - php

Question

I'm using the code below to modify the WooCommerce Is_Purchasable option so that, item Y is purchasable if item X is added to the cart.
But it gives ajax error when trying to add item Y to the cart.
Here's the code:
function aelia_get_cart_contents() {
$cart_contents = array();
/**
* Load the cart object. This defaults to the persistant cart if null.
*/
$cart = WC()->session->get( 'cart', null );
if ( is_null( $cart ) && ( $saved_cart = get_user_meta( get_current_user_id(), '_woocommerce_persistent_cart', true ) ) ) {
$cart = $saved_cart['cart'];
} elseif ( is_null( $cart ) ) {
$cart = array();
}
if ( is_array( $cart ) ) {
foreach ( $cart as $key => $values ) {
$_product = wc_get_product( $values['variation_id'] ? $values['variation_id'] : $values['product_id'] );
if ( ! empty( $_product ) && $_product->exists() && $values['quantity'] > 0 ) {
if ( $_product->is_purchasable() ) {
// Put session data into array. Run through filter so other plugins can load their own session data
$session_data = array_merge( $values, array( 'data' => $_product ) );
$cart_contents[ $key ] = apply_filters( 'woocommerce_get_cart_item_from_session', $session_data, $values, $key );
}
}
}
}
return $cart_contents;
}
// Step 1 - Keep track of cart contents
add_action('wp_loaded', function() {
// If there is no session, then we don't have a cart and we should not take
// any action
if(!is_object(WC()->session)) {
return;
}
// Product Y
global $y_cart_items;
$y_cart_items = 2986;
//Product X
global $x_cart_items;
$x_cart_items = array(
'297'
);
// Step 2
add_filter('woocommerce_is_purchasable', function($is_purchasable, $product) {
global $y_cart_items;
global $x_cart_items;
if( $product->id == $y_cart_items ) {
// make it false
$is_purchasable = false;
// get the cart items object
foreach ( aelia_get_cart_contents() as $key => $item ) {
// do your condition
if( in_array( $item['product_id'], $x_cart_items ) ) {
// Eligible product found on the cart
$is_purchasable = true;
break;
}
}
}
return $is_purchasable;
}, 10, 2);
}, 10);
// Step 3 - Explain customers why they can't add some products to the cart
add_filter('woocommerce_get_price_html', function($price_html, $product) {
if(!$product->is_purchasable() && is_product()) {
$price_html .= '<p>' . __('Add Product X to be able to purchase Product Y.', 'woocommerce') . '</p>';
}
return $price_html;
}, 10, 2);
How do I fix this? Thank you.